First Commonwealth Financial (FCF) 10-K 1 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 25, 2021	Jun. 30, 2020
Document and Entity Information [Abstract]
Document Transition Report	false
Entity Incorporation, State or Country Code	PA
Document Annual Report	true
Title of 12(b) Security	COMMON STOCK, $1 PAR VALUE
Security Exchange Name	NYSE
Entity Tax Identification Number	25-1428528
Entity Address, Address Line One	601 PHILADELPHIA STREET
Entity Address, Postal Zip Code	15701
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Entity File Number	001-11138
City Area Code	724
Local Phone Number	349-7220
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	FCF
Entity Registrant Name	FIRST COMMONWEALTH FINANCIAL CORP /PA/
Entity Central Index Key	0000712537
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		96,162,202
Entity Public Float			$ 799,866,969
Entity Shell Company	false
Entity Small Business	false
Entity Address, City or Town	INDIANA,
Entity Address, State or Province	PA

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Cash and due from banks	$ 100,009	$ 102,346
Interest-bearing bank deposits	256,572	19,510
Securities available for sale, at fair value	(831,223)	(902,292)
Securities held to maturity, at amortized cost, (Fair value $369,851 at December 31, 2020 and $338,718 at December 31, 2019)	361,844	337,123
Other investments	12,227	16,761
Loans held for sale	33,436	15,989
Loans:
Portfolio loans	6,761,183	6,189,148
Allowance for credit losses	(101,309)	(51,637)
Net loans	6,659,874	6,137,511
Premises and equipment, net	125,517	137,268
Other real estate owned	1,215	2,228
Goodwill	303,328	303,328
Amortizing intangibles, net	13,492	16,366
Bank owned life insurance	225,952	220,723
Other assets	143,415	97,328
Total assets	9,068,104	8,308,773
Deposits (all domestic):
Noninterest-bearing	2,319,958	1,690,247
Interest-bearing	5,118,708	4,987,368
Total deposits	7,438,666	6,677,615
Short-term borrowings	117,373	201,853
Subordinated debentures	170,612	170,450
Other long-term debt	56,258	56,917
Capital lease obligation	6,385	6,815
Total long-term debt	233,255	234,182
Other liabilities	210,193	139,458
Total liabilities	7,999,487	7,253,108
Shareholders’ Equity
Preferred stock, $1 par value per share, 3,000,000 shares authorized, none issued	0	0
Common stock, $1 par value per share, 200,000,000 shares authorized; 113,914,902 shares issued as of December 31, 2020 and 2019; and 96,130,751 and 98,311,840 shares outstanding at December 31, 2020 and 2019, respectively	113,915	113,915
Additional paid-in capital	494,683	493,737
Retained earnings	596,614	577,348
Accumulated other comprehensive (loss) income, net	17,233	5,579
Treasury stock (17,784,151 and 15,603,062 shares at December 31, 2020 and 2019, respectively)	(153,828)	(134,914)
Total shareholders’ equity	1,068,617	1,055,665
Total liabilities and shareholders’ equity	$ 9,068,104	$ 8,308,773

CONSOLIDATED STATEMENTS OF FI_2

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Securities held to maturity, fair value	$ 369,851	$ 338,718
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	3,000,000	3,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	113,914,902	113,914,902
Common stock, shares outstanding (in shares)	96,130,751	98,311,840
Treasury stock, shares (in shares)	17,784,151	15,603,062

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest Income
Interest and fees on loans	$ 275,189	$ 291,889	$ 257,316
Interest and dividends on investments:
Taxable interest	24,063	29,773	31,264
Interest exempt from federal income taxes	1,053	1,591	1,646
Dividends	686	1,608	1,859
Interest on bank deposits	218	403	172
Total interest income	301,209	325,264	292,257
Interest Expense
Interest on deposits	21,972	36,725	21,713
Interest on short-term borrowings	704	8,298	10,741
Interest on subordinated debentures	8,580	9,084	6,987
Interest on other long-term debt	1,419	1,016	300
Interest Expense, Lessee, Assets under Capital Lease	263	279	294
Total interest expense	32,938	55,402	40,035
Net Interest Income	268,271	269,862	252,222
Provision for credit losses	56,718	14,533	12,531
Net Interest Income after Provision for Credit Losses	211,553	255,329	239,691
Noninterest Income
Net securities gains	70	22	8,102
Trust income	9,101	8,321	7,901
Service charges on deposit accounts	16,387	18,926	18,175
Insurance and retail brokerage commissions	7,850	7,583	7,426
Income from bank owned life insurance	6,552	6,002	6,686
Gain on sale of mortgage loans	18,764	7,765	5,436
Gain on sale of other loans and assets	(4,827)	(4,793)	(5,273)
Card related interchange income	23,966	21,677	20,187
Derivative, Gain (Loss) on Derivative, Net	(2,521)	(269)	787
Swap Fee Income	1,588	3,397	1,874
Other income	7,892	7,268	6,790
Total noninterest income	94,476	85,485	88,637
Noninterest Expense
Salaries and employee benefits	118,961	112,237	105,115
Net occupancy	17,647	18,923	17,219
Furniture and equipment	15,393	15,160	14,247
Data processing	10,543	10,692	10,470
Advertising and promotion	4,679	4,250	3,956
Pennsylvania shares tax	4,500	4,602	4,875
Intangible amortization	3,689	3,344	3,217
Other professional fees and services	3,886	4,631	4,473
FDIC insurance	2,699	1,219	2,007
Asset Impairment Charges	680	1,724	1,080
Litigation and operational losses	1,411	1,687	1,162
Merger and acquisition related	0	3,536	1,637
COVID-19 related expenses	874	0	0
Voluntary retirement plan expenses	3,422	0	0
Branch consolidation expense	2,672	0	0
Other operating expenses	24,770	27,960	26,098
Total noninterest expense	215,826	209,965	195,556
Income before income taxes	90,203	130,849	132,772
Income tax provision	16,756	25,516	25,274
Net Income	$ 73,447	$ 105,333	$ 107,498
Average Shares Outstanding (in shares)	97,499,586	98,317,787	99,036,163
Average Shares Outstanding Assuming Dilution (in shares)	97,758,965	98,588,164	99,223,513
Per Share Data:
Basic Earnings Per Share (in dollars per share)	$ 0.75	$ 1.07	$ 1.09
Diluted Earnings Per Share (in dollars per share)	0.75	1.07	1.08
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.44	$ 0.40	$ 0.35
Securities held to maturity, fair value	$ 369,851	$ 338,718

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 73,447	$ 105,333	$ 107,498
Other comprehensive income (loss), before tax expense (benefit):
Unrealized holding gains on securities arising during the period	19,981	20,625	2,783
Less: reclassification adjustment for gains on securities included in net income	(70)	(22)	(8,102)
Unrealized holding (losses) gains on derivatives arising during the period	(4,467)	935	326
Reclassification adjustment for losses on derivatives included in net income	0	0	10
Unrealized (losses) gains for postretirement obligations:
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), after Reclassification Adjustment, before Tax	(537)	0	0
Net (loss) gain	(155)	(121)	144
Total other comprehensive income (loss), before income tax expense (benefit)	14,752	21,417	(4,839)
Income tax expense (benefit) related to items of other comprehensive income (loss)	3,098	4,497	(1,015)
Comprehensive Income	$ 85,101	$ 122,253	$ 103,674

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]	Treasury Stock [Member]	Previously Reported [Member]	Previously Reported [Member]Common Stock [Member]	Previously Reported [Member]Additional Paid-in-Capital [Member]	Previously Reported [Member]Retained Earnings [Member]	Previously Reported [Member]Accumulated Other Comprehensive Income (Loss), net [Member]	Previously Reported [Member]Treasury Stock [Member]	Accounting Standards Update 2018-02 [Member]	Accounting Standards Update 2018-02 [Member]Common Stock [Member]	Accounting Standards Update 2018-02 [Member]Additional Paid-in-Capital [Member]	Accounting Standards Update 2018-02 [Member]Retained Earnings [Member]	Accounting Standards Update 2018-02 [Member]Accumulated Other Comprehensive Income (Loss), net [Member]	Accounting Standards Update 2018-02 [Member]Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,344)												$ 0			$ 1,344	$ (1,344)
Beginning balance at Dec. 31, 2017	888,127	$ 113,915	$ 470,123	$ 437,416	$ (6,173)	$ (127,154)							$ 888,127	$ 113,915	$ 470,123	$ 438,760	$ (7,517)	$ (127,154)
Beginning balance, Shares Outstanding at Dec. 31, 2017		97,456,478												97,456,478
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	107,498			107,498
Total other comprehensive (loss) Income	(3,824)				(3,824)
Cash dividends declared	(34,849)			(34,849)
Treasury stock acquired	(26,189)					(26,189)
Treasury stock acquired		(1,920,544)
Treasury stock reissued	44,026		21,579	0		22,447
Treasury stock reissued, Shares Outstanding		2,908,234
Restricted stock, Shares Outstanding		74,500
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	600	$ 0	571	0		29
Ending balance at Dec. 31, 2018	975,389	$ 113,915	492,273	511,409	(11,341)	(130,867)
Ending balance, Shares Outstanding at Dec. 31, 2018		98,518,668
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	105,333			105,333
Total other comprehensive (loss) Income	16,920				16,920
Cash dividends declared	(39,394)			(39,394)
Treasury stock acquired	(6,259)					(6,259)
Treasury stock acquired		(486,849)
Treasury stock reissued	2,744		1,014	0		1,730
Treasury stock reissued, Shares Outstanding		205,021
Restricted stock, Shares Outstanding		75,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	932	$ 0	450	0		482
Ending balance at Dec. 31, 2019	$ 1,055,665						$ 1,055,665	$ 113,915	$ 493,737	$ 577,348	$ 5,579	$ (134,914)
Ending balance, Shares Outstanding at Dec. 31, 2019	98,311,840							98,311,840
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 73,447			73,447
Total other comprehensive (loss) Income	11,654				11,654
Cash dividends declared	(42,982)			(42,982)
Treasury stock acquired	(20,905)					(20,905)
Treasury stock acquired		(2,430,842)
Treasury stock reissued	1,817		459	0		1,358
Treasury stock reissued, Shares Outstanding		158,453
Restricted stock, Shares Outstanding		91,300
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	1,120	$ 0	487	0		633
Ending balance at Dec. 31, 2020	$ 1,068,617	$ 113,915	$ 494,683	596,614	$ 17,233	$ (153,828)
Ending balance, Shares Outstanding at Dec. 31, 2020	96,130,751	96,130,751
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 11,199			$ 11,199

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.44	$ 0.40	$ 0.35

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net Income	$ 73,447	$ 105,333	$ 107,498
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	56,718	14,533	12,531
Deferred Income Taxes and Tax Credits	(8,217)	2,292	3,473
Depreciation and amortization	11,653	10,370	8,046
Net gains on securities and other assets	(18,807)	(10,671)	(21,540)
Net amortization of premiums and discounts on securities	6,183	3,892	3,083
Income from increase in cash surrender value of bank owned life insurance	(6,288)	(5,998)	(5,808)
Mortgage loans originated for sale	(410,715)	(251,428)	(165,898)
Proceeds from Sale of Mortgage Loans Held-for-sale	408,877	251,968	177,287
Increase in interest receivable	(10,735)	423	(2,561)
Increase (decrease) in interest payable	(879)	(256)	383
(Increase) decrease in income taxes payable	(887)	1,484	(1,926)
Distribution from unconsolidated subsidiary	0	0	9,000
Other—net	5,349	(14,310)	11,695
Net cash provided by operating activities	105,699	107,632	135,263
Transactions with securities held to maturity:
Proceeds from Sale and Maturity of Held-to-maturity Securities	0	948	0
Proceeds from maturities and redemptions	118,905	54,632	47,614
Purchases	(85,679)	(200)	(20,650)
Transactions with securities available for sale:
Proceeds from sales	0	0	15,939
Proceeds from maturities and redemptions	472,282	189,194	140,707
Purchases	(411,178)	(138,670)	(331,969)
Purchases of FHLB stock	(22,231)	(36,850)	(52,107)
Proceeds from the redemption of FHLB stock	26,766	52,215	51,488
Proceeds from bank owned life insurance	1,444	557	2,140
Proceeds from the sale of loans	41,141	37,534	40,783
Proceeds from sales of other assets	5,531	6,822	4,477
Acquisition, net of cash acquired	0	332,468	705
Net increase in loans	(622,504)	(358,328)	(237,276)
Purchases of premises and equipment	(7,615)	(17,380)	(9,599)
Net cash (used in) provided by investing activities	(483,138)	122,942	(347,748)
Financing Activities
Net increase (decrease) in federal funds purchased	0	(11,000)	11,000
Net (decrease) increase in other short-term borrowings	(84,480)	(508,970)	3,357
Net increase in deposits	761,398	308,783	176,558
Repayments of other long-term debt	(659)	(634)	(23,598)
Proceeds from Issuance of Long-term Debt	0	50,000	98,026
Repayments of Long-term Capital Lease Obligations	430	402	373
Dividends paid	(42,982)	(39,394)	(34,849)
Proceeds from reissuance of treasury stock	222	211	208
Purchase of treasury stock	(20,905)	(6,259)	(26,189)
Net cash provided by (used in) financing activities	612,164	(207,665)	204,140
Net (decrease) increase in cash and cash equivalents	234,725	22,909	(8,345)
Cash and cash equivalents at January 1	121,856	98,947	107,292
Cash and cash equivalents at December 31	$ 356,581	$ 121,856	$ 98,947

Statement of Accounting Policie

Statement of Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Statement of Accounting Policies	Statement of Accounting Policies General The following summary of accounting and reporting policies is presented to aid the reader in obtaining a better understanding of the consolidated financial statements of First Commonwealth Financial Corporation and its subsidiaries (“First Commonwealth”) contained in this report. First Commonwealth's subsidiaries include, First Commonwealth Bank ("FCB" or the "Bank"), First Commonwealth Insurance Agency, Inc. ("FCIA"), FRAMAL and First Commonwealth Financial Advisors, Inc ("FCFA"). The financial information is presented in accordance with generally accepted accounting principles and general practice for financial institutions in the United States of America. In preparing financial statements, management is required to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. In addition, these estimates and assumptions affect revenues and expenses in the financial statements and as such, actual results could differ from those estimates. Through its subsidiaries, which include a commercial bank and an insurance agency, First Commonwealth provides a full range of loan, deposit, trust, insurance and personal financial planning services primarily to individuals and small to middle market businesses in 26 counties in central and western Pennsylvania as well as throughout Ohio. First Commonwealth has determined that it has one business segment. First Commonwealth is subject to regulations of certain state and federal agencies. These regulatory agencies periodically examine First Commonwealth for adherence to laws and regulations. Basis of Presentation The accompanying Consolidated Financial Statements include the accounts of First Commonwealth previously defined above. All material intercompany transactions have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current period's presentation. Equity investments of less than a majority but at least 20% ownership are accounted for by the equity method and classified as “Other assets.” Earnings on these investments are reflected in “Other income” on the Consolidated Statements of Income, as appropriate, in the period earned. Investment Securities Debt securities that First Commonwealth has the positive intent and ability to hold to maturity are classified as securities held to maturity and are reported at amortized cost adjusted for amortization of premium and accretion of discount on a level yield basis. Debt and equity securities that are bought and held principally for the purpose of selling them in the near term are to be classified as trading securities and reported at fair value, with unrealized gains and losses included in earnings. Debt securities not classified as either held-to-maturity securities or trading securities are classified as securities available for sale and are reported at fair value, with unrealized gains and losses that are not related to impairment excluded from earnings and reported as a component of other comprehensive income, which is included in shareholders’ equity, net of deferred taxes. First Commonwealth has securities classified as held to maturity and available for sale and does not engage in trading activities. First Commonwealth utilizes the specific identification method to determine the net gain or loss on debt securities and the average cost method to determine the net gain or loss on the equity securities. First Commonwealth conducts a comprehensive review of the investment portfolio on a quarterly basis to evaluate for expected credit losses. When evaluating available-for-sale securities, management first considers whether we intend to sell the security, or if it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis. If there is intent to sell, the security's amortized cost is written down to fair value through income. Otherwise, available-for-sale securities whose market values have fallen below their book value are evaluated at the issuer-specific level to determine if the decline in value is a result of credit losses. Issuer-specific securities include obligations of U.S. Government agencies and sponsored enterprises, single issue trust preferred securities, corporate debentures and obligations of states and political subdivisions. Further analysis of these securities includes a review of research reports, analysts’ recommendations, credit rating changes, news stories, annual reports, impact of interest rate changes and any other relevant information pertaining to the affected security. Any loss not determined to be a credit loss is recorded as a reduction to shareholders equity, through other comprehensive income. Held-to-maturity securities are evaluated for impairment on a quarterly basis using historical probability of default and loss given default information specific to the investment category. If this evaluation determines that credit losses exist an allowance for credit loss is recorded and included in earnings as a component of credit loss expense. Mortgage Loans Held for Sale Certain residential mortgage loans are originated for sale in the secondary mortgage loan market with the majority sold with servicing rights released. These loans are classified as loans held for sale and are carried at the estimated market value on an aggregate basis. Market value is determined on the basis of rates obtained in the respective secondary market for the type of loan held for sale. Loans are generally sold at a premium or discount from the carrying amount of the loan. Such premium or discount is recognized at the date of sale. Gain or loss on the sale of loans is recorded in non-interest income at the time consideration is received and all other criteria for sales treatment have been met. Loans Loans are carried at the principal amount outstanding. Interest is accrued as earned. Loans held for sale are carried at the lower of cost or fair market value determined on an individual basis. First Commonwealth considers a loan to be past due and still accruing interest when payment of interest or principal is contractually past due but the loan is both well secured and in the process of collection. For installment, mortgage, term and other loans with amortizing payments that are scheduled monthly, 90 days past due is reached when four monthly payments are due and unpaid. For demand, time and other multi-payment obligations with payments scheduled other than monthly, delinquency status is calculated using number of days instead of number of payments. Revolving credit loans, including personal credit lines and home equity lines, are considered to be 90 days past due when the borrower has not made the minimum payment for four monthly cycles. A loan is placed in nonaccrual status when, based on current information and events, it is probable that First Commonwealth will be unable to fully collect principal or interest due according to the contractual terms of the loan. A loan is also placed in nonaccrual status when, based on regulatory definitions, the loan is maintained on a “cash basis” due to the weakened financial condition of the borrower. When a determination is made to place a loan in nonaccrual status, all accrued and unpaid interest is reversed. Nonaccrual loans are restored to accrual status when, based on a sustained period of repayment by the borrower in accordance with the contractual terms of the loan, First Commonwealth expects repayment of the remaining contractual principal and interest or when the loan otherwise becomes well-secured and in the process of collection. First Commonwealth considers a loan to be a troubled debt restructured loan when the loan terms have been renegotiated to provide a reduction or deferral of principal or interest as a result of the financial difficulties experienced by the borrower, who could not obtain comparable terms from alternate financing sources. Troubled debt restructured loans are considered to be nonperforming loans. A loan is considered to be nonperforming when, based on current information and events, it is expected that First Commonwealth will be unable to collect principal or interest that is due in accordance with contractual terms of the loan. Nonperforming loans include nonaccrual loans and troubled debt restructured loans. Loan impairment is measured based on the present value of expected cash flows discounted at the loan’s effective interest rate or, as a practical expedient, at the loan’s observable market price or the fair value of the collateral if the loan is collateral dependent. For loans other than those that First Commonwealth expects repayment through liquidation of the collateral, when the remaining recorded investment in the loan is less than or equal to the present value of the expected cash flows, income is applied as a reduction to loan principal rather than interest income. Loans deemed uncollectible are charged off through the allowance for credit losses. Factors considered in assessing ultimate collectability include past due status, financial condition of the borrower, collateral values and debt covenants including secondary sources of repayment by guarantors. Payments received on previously charged off loans are recorded as recoveries in the allowance for credit losses. Acquired loans are recorded at estimated fair value on the date of acquisition with no carryover of the related allowance for credit losses. The fair value of acquired loans is determined by estimating the principal and interest cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. The estimated fair value considers factors such as loan term, internal risk rating, delinquency status, prepayment rates, estimated value of the underlying collateral and the current interest rate environment. Loan Fees Loan origination and commitment fees, net of associated direct costs, are deferred and the net amount is amortized as an adjustment to the related loan yield on the interest method, generally over the contractual life of the related loans or commitments. Other Real Estate Owned Real estate, other than bank premises, is recorded at fair value less estimated selling costs at the time of acquisition. After that time, other real estate is carried at the lower of cost or fair value less estimated costs to sell. Fair value is determined based on an independent appraisal. Expenses related to holding the property and rental income earned on the property are generally reflected in earnings in the current period. Depreciation is not recorded on the other real estate owned properties. Allowance for Credit Losses for Loans On January 1, 2020, First Commonwealth adopted ASU 2016-13 Financial Instruments - Credit Losses ("Topic 326"), which replaces the incurred loss methodology for determining our allowance for credit losses and related provision for credit losses with an expected loss methodology that is referred to as the Current Expected Credit Loss ("CECL") model. The measurement of expected credit losses under the CECL methodology is applicable to financial assets measured at amortized cost, including our loans. We adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost and off-balance sheet credit exposures and recognized a cumulative effect adjustment reducing retained earnings by $11.2 million, net of tax. First Commonwealth made the accounting policy election to exclude accrued interest from the allowance for credit loss calculation because these balances are written off or reversed when a loan is placed in non-accrual status. In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments, as compared to loan segments under the incurred model, to align with the methodology applied in determining the allowance under CECL. Refer to Note 9, " Loans and Allowance for Credit Losses" for further discussion of these portfolio segments. Under CECL, the allowance for credit losses is calculated by pooling loans of similar credit risk characteristics and applying a discounted cash flow methodology after incorporating probability of default and loss given default estimates. Probability of default represents an estimate of the likelihood of default and loss given default measures the expected loss upon default. Inputs impacting the expected losses includes a forecast of macroeconomic factors, using a weighted forecast from a nationally recognized firm. Our model incorporates a one-year forecast of macroeconomic factors, after which the factors revert back to the historical mean over a one-year period. Results for reporting periods beginning after January 1, 2020 are presented under ASU 2016-13 while prior period amounts continue to be reported in accordance with previously applicable GAAP. Prior to January 1, 2020, the allowance for credit losses was estimated based on managements assessment of probable estimated losses. In addition to loan category, the major loan classifications used in the allowance for credit losses calculation include pass, other assets especially mentioned (“OAEM”), substandard and doubtful. Additional information related to these credit quality categories is provided in Note 9, "Loans and Allowance for Credit Losses." Under this incurred methodology, the allowance calculation uses net historical charge-off trends to estimate probable unconfirmed losses for each loan category. A multiplier known as the emergence factor is applied to the historical loss rates for non-criticized loans. The emergence factor is calculated by loan category and represents the average time period from when a loss is incurred until the bank experiences a charge-off against the loan. Before applying the adjusted historical loss experience percentages, loan balances are reduced by the portion of the loan balances which are subject to guarantee by a government agency. Under the incurred model, loans acquired with evidence of credit deterioration were evaluated and not considered to be significant. The premium or discount estimated through the loan fair value calculation is recognized in interest income on a level yield or straight-line basis over the remaining contractual life of the loans. Additional credit deterioration on acquired loans, in excess of the original credit discount embedded in the fair value determination on the date of acquisition, was recognized in the allowance for credit losses through the provision for loan losses. As part of both CECL and the incurred methodology, all nonperforming credits, which includes nonaccrual loans and all troubled debt restructurings ("TDRs"), in excess of $250 thousand are individually evaluated on a quarterly basis. A specific reserve is established for individually evaluated loans in an amount equal to the total amount of estimated losses for the loans that are reviewed. Based on this reserve as a percentage of reviewed loan balances, a reserve is also established for the nonperforming loan balances that are not individually reviewed. An additional component of the allowance is determined by management based on a qualitative analysis of certain factors related to portfolio risks that are not incorporated in the calculated model. Factors considered by management include lending practices, ability and experience of the credit staff, the overall lending environment and external factors such as the regulatory environment and competition. Portfolio risks include unusual changes or recent trends in specific portfolios such as unexpected changes in the trends or levels of delinquency. No matter how detailed an analysis of potential credit losses is performed, these estimates are inherently imprecise. Management must make estimates using assumptions and information that is often subjective and changes rapidly. Allowance for Off-Balance Sheet Credit Exposures First Commonwealth maintains an allowance for off-balance sheet credit exposure at a level deemed sufficient to absorb losses that are inherent to off-balance sheet credit risk. Off-balance sheet credit exposure includes commitments to extend credit, standby letters of credit and commercial letters of credit. The Company’s methodology for assessing the appropriateness of the allowance for off-balance sheet credit exposure consists of analysis of historical usage trends. The calculation begins with historical usage trends related to lines of credit as well as letters of credit and then utilizes those figures to determine the probable usage of available lines. These values are then adjusted by the expected loss percentage calculated for comparable loan categories as part of the allowance for credit losses for loans. This amount is adjusted quarterly and any change to the allowance is reported as part of provision expense on the Consolidated Statements of Income. The allowance for off-balance sheet credit exposures is reflected in "Other Liabilities" in the Consolidated Statements of Finance Condition. Bank Owned Life Insurance First Commonwealth and the banks that First Commonwealth has acquired have purchased insurance on the lives of certain groups of employees. The policies accumulate asset values to meet future liabilities, including the payment of employee benefits such as health care. Increases in the cash surrender value are recorded as non-interest income in the Consolidated Statements of Income and cash receipts and disbursements are included in "Operating Activities" in the Consolidated Statements of Cash Flows. Under some of these policies, the beneficiaries receive a portion of the death benefit. The net present value of the future death benefits scheduled to be paid to the beneficiaries was $4.6 million and $4.2 million as of December 31, 2020 and 2019, respectively, and is reflected in "Other Liabilities" on the Consolidated Statements of Financial Condition. Premises, Equipment and Lease Commitments Premises and equipment are carried at cost less accumulated depreciation on First Commonwealth’s Consolidated Statements of Financial Condition. Depreciation is computed on the straight-line and accelerated methods over the estimated useful life of the asset. A straight-line depreciation method was used for substantially all furniture and equipment. The straight-line depreciation method was used for buildings and improvements. Charges for maintenance and repairs are expensed as incurred. Leasehold improvements are expensed over the term of the lease or the estimated useful life of the improvement, whichever is shorter. Software costs are amortized on a straight-line basis over a period not to exceed 7 years. A right-of-use asset and related lease liability is recognized on the Consolidated Statements of Financial Condition for operating leases First Commonwealth has entered to lease certain office facilities. These amounts are reported as components of premises and equipment and other liabilities. Short-term operating leases, which are leases with an original term of 12 months or less and do not have a purchase option that is likely to be exercised, are not recognized as part of the right-of-use asset or lease liability. First Commonwealth has no material leasing arrangements for which it is the lessor of property or equipment. Business Combinations Business combinations are accounted for by using the acquisition method of accounting. Under the acquisition method, identifiable assets acquired and liabilities assumed at the acquisition date are measured at their fair values as of that date, and are recognized separately from goodwill. The difference between the purchase price and the fair value of the net assets acquired is recorded as goodwill. Results of operations of the acquired entities are included in the consolidated statement of income from the date of acquisition. Acquisition costs are expensed when incurred. Goodwill Intangible assets resulting from acquisitions under the purchase method of accounting consist of goodwill and other intangible assets (see “Other Intangible Assets” section below). Goodwill is not amortized and is subject to at least annual assessments for impairment. First Commonwealth reviews goodwill annually and again at any quarter-end if a material event occurs during the quarter that may affect goodwill. When circumstances indicate that it is more likely than not that fair value is less than carrying value, a triggering event has occurred and a quantitative impairment test is performed. Goodwill is evaluated for potential impairment by determining if our fair value has fallen below carrying value. Other Intangible Assets Other intangible assets consist of core deposits and customer lists obtained through acquisitions. Core deposit intangibles are amortized over their estimated lives using the present value of the benefit of the core deposits and straight-line methods of amortization. Customer list intangibles are amortized over the expected lives using expected cash flows based on retention of the customer base. These intangibles are evaluated for impairment on an annual basis and when events or changes in circumstances indicate that the carrying amount may not be recoverable. Accounting for the Impairment of Long-Lived Assets First Commonwealth reviews long-lived assets, such as premises and equipment and intangibles, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. These changes in circumstances may include a significant decrease in the market value of an asset or the extent or manner in which an asset is used. If there is an indication that the carrying amount of an asset may not be recoverable, future undiscounted cash flows expected to result from the use of the asset are estimated. If the sum of the expected cash flows is less than the carrying value of the asset, a loss is recognized for the difference between the carrying value and fair value of the asset. Long-lived assets classified as held for sale are measured at the lower of their carrying amount or fair value less cost to sell. Depreciation or amortization is discontinued on long-lived assets classified as held for sale. Income Taxes First Commonwealth records taxes in accordance with the asset and liability method of FASB ASC Topic 740, “Income Taxes,” whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amount of existing assets and liabilities and their respective tax bases given the provisions of the enacted tax laws. Deferred tax assets are reduced, if necessary, by the amount of such benefits that are more likely than not expected to be realized based upon available evidence. In accordance with FASB ASC Topic 740, interest or penalties incurred for taxes will be recorded as a component of noninterest expense. Comprehensive Income Disclosures “Other Comprehensive Income” (comprehensive income, excluding net income) includes the after-tax effect of changes in unrealized holding gains and losses on available-for-sale securities, changes in the funded status of defined benefit postretirement plans and changes in the fair value of cash flow hedges. Comprehensive income is reported in the accompanying Consolidated Statements of Comprehensive Income, net of tax. Cash and Cash Equivalents For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, federal funds sold and interest-bearing bank deposits. Generally, federal funds are sold for one-day periods. Derivatives and Hedging Activities First Commonwealth accounts for derivative instruments and hedging activities in accordance with FASB ASC Topic 815, “Derivatives and Hedging.” All derivatives are evaluated at inception as to whether or not they are hedging or non-hedging activities, and appropriate documentation is maintained to support the final determination. First Commonwealth recognizes all derivatives as either assets or liabilities on the Consolidated Statements of Financial Condition and measures those instruments at fair value. For derivatives designated as fair value hedges, changes in the fair value of the derivative and the hedged item related to the hedged risk are recognized in earnings. Any hedge ineffectiveness would be recognized in the income statement line item pertaining to the hedged item. For derivatives designated as cash flow hedges, changes in fair value of the effective portion of the cash flow hedges are reported in other comprehensive income ("OCI"). When the cash flows associated with the hedged item are realized, the gain or loss included in OCI is recognized in the Consolidated Statement of Income. When First Commonwealth purchases a portion of a commercial loan that has an existing interest rate swap, it enters a Risk Participation Agreement with the counterparty and assumes the credit risk of the loan customer related to the swap. Any fee paid to First Commonwealth as a result of the risk participation agreement is offset by credit risk of the counterparties and is recognized in the income statement. Credit risk on the risk participation agreements is determined after considering the risk rating, probability of default and loss given default of the counterparties. Management periodically reviews contracts from various functional areas of First Commonwealth to identify potential derivatives embedded within selected contracts. As of December 31, 2020, First Commonwealth has interest rate derivative positions that are designated as hedging instruments and others that are not designated as hedging instruments. See Note 7, “Derivatives,” for a description of these instruments. Earnings Per Common Share Basic earnings per share excludes dilution and is computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted earnings per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of the entity. For all periods presented, the dilutive effect on average shares outstanding is the result of unvested restricted stock grants. Fair Value Measurements In accordance with FASB ASC Topic 820, “Fair Value Measurements and Disclosures,” First Commonwealth groups financial assets and financial liabilities measured at fair value into three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: • Level 1—Valuations for assets and liabilities traded in active exchange markets, such as the New York Stock Exchange. Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities. • Level 2—Valuations for assets and liabilities traded in less active dealer or broker markets. Valuations are obtained for identical or comparable assets or liabilities from alternative pricing sources with reasonable levels of price transparency. Level 2 securities include U.S. Government securities issued by Agencies and Sponsored Enterprises, Obligations of States and Political Subdivisions, certain corporate securities, FHLB stock, loans held for sale, interest rate derivatives that include interest rate swaps, risk participation agreements and foreign currency contracts, certain other real estate owned and certain nonperforming loans. • Level 3—Valuations for assets and liabilities that are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. If the inputs used to provide the evaluation are unobservable and/or there is very little, if any, market activity for the security or similar securities, the securities would be considered Level 3 securities. Level 3 valuations incorporate certain assumptions and projections in determining the fair value assigned to such assets or liabilities. The assets included in Level 3 are nonmarketable equity investments, certain other real estate owned and certain nonperforming loans. In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon pricing models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. See Note 17 “Fair Values of Assets and Liabilities” for additional information. Revenue from Contracts with Customers First Commonwealth records revenue from contracts with customers in accordance with ASC Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. A significant component of the Company's revenue, net interest earned on financial assets and liabilities, is excluded from the scope of Topic 606. First Commonwealth generally fully satisfies its performance obligations on its contracts with customers as services are rendered and the transaction prices are typically fixed; charged either on a periodic basis or based on activity. Because performance obligations are satisfied as services are rendered and the transaction prices are fixed, the Company has made no significant judgments in applying the revenue guidance prescribed in Topic 606 that affect the determination of the amount and timing of revenue from contracts with customers.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisition	Acquisition Santander Branch Acquisition On September 6, 2019, the Company's banking subsidiary, First Commonwealth Bank, completed its acquisition of 14 full service branches from Santander Bank N.A. ("Santander") receiving $329.5 million in cash. This acquisition further expands the Company's market into State College, Lock Haven, Williamsport and Lewisburg, Pennsylvania and included the purchase of $100.0 million in loans and $471.4 million in deposits. The table below summarizes the final purchase price allocation and the net assets acquired (at fair value) and consideration received in connection with the Santander acquisition (dollars in thousands): Consideration Received Cash received $ 329,533 Fair Value of Assets Acquired Cash and cash equivalents 2,935 Loans 99,956 Premises and other equipment 3,637 Core deposit intangible 5,615 Other assets 770 Total assets acquired 112,913 Fair Value of Liabilities Assumed Deposits 471,386 Other liabilities 186 Total liabilities assumed 471,572 Total Fair Value of Identifiable Net Assets (358,659) Goodwill $ 29,126 The goodwill of $29.1 million arising from the acquisition represents the value of synergies and economies of scale expected from combining the operations of the Company with the branches acquired from Santander. The goodwill for this transaction is expected to be deducted over a 15-year period for income tax purposes. The Company determined that this acquisition constitutes a business combination as defined in FASB ASC Topic 805, “Business Combinations.” Accordingly, as of the date of the acquisition, the Company recorded the assets acquired and liabilities assumed at fair value. The Company determined fair values in accordance with the guidance provided in FASB ASC Topic 820, “Fair Value Measurements and Disclosures.” Acquired loans were recorded at fair value with no carryover of the related allowance for loan losses. At the date of acquisition, none of the loans were accounted for under the guidance of ASC Topic 310-30, “Receivables-Loans and Debt Securities Acquired with Deteriorated Credit Quality.” The fair value of acquired loans and certificate of deposits is established by discounting the expected future cash flows with a market discount rate for like maturities and risk instruments. The $100.0 million fair value of acquired loans is the result of $101.2 million in loans acquired from Santander and the recognition of a net combined yield and credit mark adjstment of $1.2 million. The $471.4 million fair value of acquired deposits is the result of $471.0 million in deposits acquired and the recognition of a yield mark adjustment of $0.4 million on the certificate of deposits. A $5.6 million core deposit intangible was recognized for core deposits acquired. Costs related to the acquisition totaled $3.7 million in 2019. These amounts were expensed as incurred and are recorded as a merger and acquisition related expense in the Consolidated Statements of Income.

Supplemental Comprehensive Inco

Supplemental Comprehensive Income Disclosures	12 Months Ended
	Dec. 31, 2020
Supplemental Comprehensive Income Disclosures [Abstract]
Supplemental Comprehensive Income Disclosures	Supplemental Comprehensive Income Disclosures The following table identifies the related tax effects allocated to each component of other comprehensive income in the Consolidated Statements of Comprehensive Income as of December 31. Reclassification adjustments related to securities available for sale are included in the “ Net securities gains ” line in the Consolidated Statements of Income and reclassification adjustments related to losses on derivatives are included in the "Other operating expenses" line in the Consolidated Statements of Income. 2020 2019 2018 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains (losses) on securities: Unrealized holding gains on securities arising during the period $ 19,981 $ (4,196) $ 15,785 $ 20,625 $ (4,331) $ 16,294 $ 2,783 $ (585) $ 2,198 Reclassification adjustment for gains on securities included in net income (70) 15 (55) (22) 5 (17) (8,102) 1,701 (6,401) Total unrealized gains (losses) on securities 19,911 (4,181) 15,730 20,603 (4,326) 16,277 (5,319) 1,116 (4,203) Unrealized gains (losses) on derivatives: Unrealized holding (losses) gains on derivatives arising during the period (4,467) 938 (3,529) 935 (196) 739 326 (68) 258 Reclassification adjustment for losses on derivatives included in net income — — — — — — 10 (3) 7 Total unrealized (losses) gains on derivatives (4,467) 938 (3,529) 935 (196) 739 336 (71) 265 Unrealized (losses) gains for postretirement obligations: Prior service cost (537) 113 (424) — — — — — — Net (loss) gain (155) 32 (123) (121) 25 (96) 144 (30) 114 Total unrealized (losses) gains for postretirement obligations (692) 145 (547) (121) 25 (96) 144 (30) 114 Total other comprehensive income (loss) $ 14,752 $ (3,098) $ 11,654 $ 21,417 $ (4,497) $ 16,920 $ (4,839) $ 1,015 $ (3,824) The following table details the change in components of OCI for the year-ended December 31: 2020 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at December 31 $ 4,580 $ 634 $ 365 $ 5,579 Other comprehensive income before reclassification adjustment 15,785 (3,529) 12,256 Amounts reclassified from accumulated other comprehensive income (loss) (55) — (55) Prior service cost (424) (424) Net gain (123) (123) Net other comprehensive income during the period 15,730 (3,529) (547) 11,654 Balance at December 31 $ 20,310 $ (2,895) $ (182) $ 17,233 2019 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (11,697) $ (105) $ 461 $ (11,341) Other comprehensive income before reclassification adjustment 16,294 739 17,033 Amounts reclassified from accumulated other comprehensive income (loss) (17) — (17) Net gain (96) (96) Net other comprehensive income during the period 16,277 739 (96) 16,920 Balance at December 31 $ 4,580 $ 634 $ 365 $ 5,579 2018 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (6,166) $ (306) $ 299 $ (6,173) Cumulative effect of adoption of ASU 2018-02 (1,328) (64) 48 (1,344) Balance at January 1 (7,494) (370) 347 (7,517) Other comprehensive income before reclassification adjustment 2,198 258 2,456 Amounts reclassified from accumulated other comprehensive income (loss) (6,401) 7 (6,394) Net gain 114 114 Net other comprehensive income during the period (4,203) 265 114 (3,824) Balance at December 31 $ (11,697) $ (105) $ 461 $ (11,341)

Supplemental Cash Flow Disclosu

Supplemental Cash Flow Disclosures	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Disclosures	Supplemental Cash Flow Disclosures The following table presents information related to cash paid during the year for interest and income taxes as well as detail on non-cash investing and financing activities for the years ended December 31: 2020 2019 2018 (dollars in thousands) Cash paid during the period for: Interest $ 33,964 $ 56,005 $ 40,071 Income taxes 25,914 21,787 23,826 Non-cash investing and financing activities: Loans transferred to other real estate owned and repossessed assets 3,865 4,723 4,334 Fair value of loans transferred from held to maturity to available for sale 37,305 30,359 37,367 Loans transferred from available for sale to held to maturity 4,335 482 — Gross increase (decrease) in market value adjustment to securities available for sale 19,911 20,604 (5,319) Gross (decrease) increase in market value adjustment to derivatives (4,467) 935 336 Investments committed to purchase, not settled (34,185) 25,484 — Increase in limited partnership investment unfunded commitment — 1,469 — Net assets (liabilities) acquired through acquisition — (361,595) 21,834 Proceeds from death benefit on bank-owned life insurance not received (384) 484 — Treasury shares issued 1,594 2,531 2,257

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share The following table summarizes the composition of the weighted-average common shares (denominator) used in the basic and diluted earnings per share computation for the years ending December 31: 2020 2019 2018 Weighted average common shares issued 113,914,902 113,914,902 113,914,902 Average treasury shares (16,254,304) (15,447,299) (14,747,687) Average deferred compensation shares (42,751) (37,496) (37,411) Average unearned nonvested shares (118,261) (112,320) (93,641) Weighted average common shares and common stock equivalents used to calculate basic earnings per share 97,499,586 98,317,787 99,036,163 Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share 203,836 231,957 149,939 Additional common stock equivalents (deferred compensation) used to calculated diluted earnings per share 55,543 38,420 37,411 Weighted average common shares and common stock equivalents used to calculate diluted earnings per share 97,758,965 98,588,164 99,223,513 Per Share Data Basic Earnings Per Share $ 0.75 $ 1.07 $ 1.09 Diluted Earnings Per Share $ 0.75 $ 1.07 $ 1.08 The following table shows the number of shares and the price per share related to common stock equivalents that were not included in the computation of diluted earnings per share for the years ended December 31, because to do so would have been anti-dilutive. 12/31/2020 12/31/2019 12/31/2018 Price Range Price Range Price Range Shares From To Shares From To Shares From To Restricted Stock 92,499 $ 13.72 $ 15.44 81,730 $ 12.99 $ 15.44 71,560 $ 8.84 $ 14.49 Restricted Stock Units 106,931 $ 12.43 $ 15.37 26,217 $ 16.62 $ 16.62 — $ — $ —

Cash and Due from Banks

Cash and Due from Banks	12 Months Ended
	Dec. 31, 2020
Cash and Due from Banks [Abstract]
Cash and Due from Banks	Cash and Due from BanksRegulations of the Board of Governors of the Federal Reserve System impose uniform reserve requirements on all depository institutions with transaction accounts, such as checking accounts and NOW accounts. Reserves are maintained in the form of vault cash or balances held with the local Federal Reserve Bank. First Commonwealth Bank maintained average balances of $173.2 million during 2020 and $14.7 million during 2019 with the Federal Reserve Bank of Cleveland.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives Derivatives Not Designated as Hedging Instruments First Commonwealth is a party to interest rate derivatives that are not designated as hedging instruments. These derivatives relate to interest rate swaps that First Commonwealth enters into with customers to allow customers to convert variable rate loans to a fixed rate. First Commonwealth pays interest to the customer at a floating rate on the notional amount and receives interest from the customer at a fixed rate for the same notional amount. At the same time the interest rate swap is entered into with the customer, an offsetting interest rate swap is entered into with another financial institution. First Commonwealth pays the other financial institution interest at the same fixed rate on the same notional amount as the swap entered into with the customer, and receives interest from the financial institution for the same floating rate on the same notional amount. The changes in the fair value of the swaps offset each other, except for the credit risk of the counterparties, which is determined by taking into consideration the risk rating, probability of default and loss given default for all counterparties. We have 36 risk participation agreements with financial institution counterparties for interest rate swaps related to loans in which we are a participant. The risk participation agreements provide credit protection to the financial institution should the borrower fail to perform on its interest rate derivative contract with the financial institution. We have 14 risk participation agreements with financial institution counterparties for interest rate swaps related to loans in which we are the lead bank. The risk participation agreement provides credit protection to us should the borrower fail to perform on its interest rate derivative contract with us. First Commonwealth is also party to interest rate caps and collars that are not designated as hedging instruments. The interest rate caps relate to contracts that First Commonwealth enters into with loan customers that provide a maximum interest rate on their variable rate loan. At the same time the interest rate cap is entered into with the customer, First Commonwealth enters into an offsetting interest rate cap with another financial institution. The notional amount and maximum interest rate on both interest cap contracts are identical. The interest rate collars relate to contracts that First Commonwealth enters into with loan customers that provides both a maximum and minimum interest rate on their variable rate loan. At the same time the interest rate collar is entered into with the customer, First Commonwealth enters into an offsetting interest rate collar with another financial institution. The notional amount and the maximum and minimum interest rates on both interest collar contracts are identical. The fee received, less the estimate of the loss for the credit exposure, was recognized in earnings at the time of the transaction. Derivatives Designated as Hedging Instruments In 2015, the Company entered into an interest rate swap contract, which was designated as a cash flow hedge. This contract, which had a total notional amount of $70.0 million, matured on March 4, 2019. The periodic net settlement of interest rate swaps was an adjustment to "Interest and fees on loans" in the Consolidated Statements of Income. For the year ended December 31, 2019 and 2018, there was a negative impact of $0.1 million and $0.6 million, respectively, on interest income as a result of these interest rate swaps. In August 2019, the Company entered into two interest rate swap contracts that are designated as cash flow hedges. These contracts mature on August 15, 2024 and August 15, 2026 and have notional amounts of $30.0 million and $40.0 million, respectively. The Company's risk management objective for these hedges is to reduce its exposure to variability in expected future cash flows related to interest payments made on subordinated debentures benchmarked to the 3-month LIBOR rate. Therefore, the interest rate swaps convert the interest rate benchmark on the first $70.0 million of 3-month LIBOR based subordinated debentures to a fixed rate. The periodic net settlement of these interest rate swaps are recorded as an adjustment to "Interest on subordinated debentures" in the Consolidated Statement of Income. For the year ended December 31, 2020, interest expense increased by $0.4 million as a result of these interest rate swaps. Changes in the fair value of the cash flow hedges are reported on the balance sheet and in OCI. When the cash flows associated with the hedged item are realized, the gain or loss included in OCI is recognized in "Interest on subordinated debentures," the same line item in the Consolidated Statements of Income as the income on the hedged items. The cash flow hedges were highly effective at December 31, 2020 and changes in the fair value attributed to hedge ineffectiveness were not material. The Company also enters into interest rate lock commitments in conjunction with its mortgage origination business. These are commitments to originate loans whereby the interest rate on the loan is determined prior to funding and the customers have locked into that interest rate. The Company locks in the rate with an investor and commits to deliver the loan if settlement occurs (“best efforts”) or commits to deliver the locked loan in a binding (“mandatory”) delivery program with an investor. Loans under mandatory rate lock commitments are covered under forward sales contracts of mortgage-backed securities (“MBS”). Forward sales contracts of MBS are recorded at fair value with changes in fair value recorded in "Noninterest income" in the Consolidated Statements of Income. The impact to noninterest income for the years ended December 31, 2020 and 2019 was an increase of $0.4 million and $0.1 million, respectively, and the impact to noninterest expense for the year ended December 31, 2018 was a decrease of $0.2 million. Interest rate lock commitments and commitments to deliver loans to investors are considered derivatives. The market value of interest rate lock commitments and best efforts contracts are not readily ascertainable with precision because they are not actively traded in stand-alone markets. We determine the fair value of rate lock commitments and delivery contracts by measuring the fair value of the underlying asset, which is impacted by current interest rates and taking into consideration the probability that the rate lock commitments will close or will be funded. At December 31, 2020, the underlying funded mortgage loan commitments had a carrying value of $25.0 million and a fair value of $28.4 million, while the underlying unfunded mortgage loan commitments had a notional amount of $47.9 million. At December 31, 2019, the underlying funded mortgage loan commitments had a carrying value of $9.8 million and a fair value of $10.7 million, while the underlying unfunded mortgage loan commitments had a notional amount of $25.5 million. In addition, a small amount of interest income on loans is exposed to changes in foreign exchange rates. Several commercial borrowers have a portion of their operations outside of the United States and borrow funds on a short-term basis to fund those operations. In order to reduce the risk related to the translation of foreign denominated transactions into U.S. dollars, the Company enters into foreign exchange forward contracts. These contracts relate principally to the Euro and the Canadian dollar. The contracts are recorded at fair value with changes in fair value recorded in "Other operating expenses" in the Consolidated Statements of Income. The impact on other noninterest expense for the year ended December 31, 2020 totaled $18 thousand. At December 31, 2020, the underlying loans had both a carrying value and a fair value of $2.1 million. At December 31, 2019, the underlying loans had both a carrying value and a fair value of $4.8 million. The following table depicts the credit value adjustment recorded relative to the notional amount of derivatives outstanding as well as the notional amount of risk participation agreements participated to other banks at December 31: 2020 2019 (dollars in thousands) Derivatives not Designated as Hedging Instruments Credit value adjustment $ (2,792) $ (272) Notional Amount: Interest rate derivatives 631,446 587,275 Interest rate caps 66,527 87,188 Interest rate collars 35,354 35,354 Risk participation agreements 220,280 164,632 Sold credit protection on risk participation agreements (78,522) (69,011) Interest rate options 47,874 25,460 Derivatives Designated as Hedging Instruments Interest rate swaps: Fair value adjustment (3,665) 801 Notional Amount 70,000 70,000 Interest rate forwards: Fair value adjustment (483) (63) Notional Amount 65,000 30,000 Foreign exchange forwards: Fair value adjustment (5) (41) Notional Amount 2,119 4,789 The table below presents the amount representing the change in the fair value of derivative assets and derivative liabilities attributable to credit risk included in “Other income” on the Consolidated Statements of Income for the years ended December 31: 2020 2019 2018 (dollars in thousands) Non-hedging interest rate derivatives: (Decrease) increase in other income $ (981) $ (269) $ 787 Decrease in other expense — (352) (332) Hedging interest rate derivatives: Decrease in interest and fees on loans — (118) (590) Increase (decrease) in interest from subordinated debentures 449 (159) — Increase in other expense — 7 10 Hedging interest rate forwards: Increase in other income 420 106 — Decrease in other expense — — (189) Hedging interest rate derivatives: Increase in other expense 18 5 15 The fair value of our derivatives is included in a table in Note 17, “Fair Values of Assets and Liabilities,” in the line items “Other assets” and “Other liabilities.”

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities Securities Available for Sale Below is an analysis of the amortized cost and fair values of securities available for sale at December 31: 2020 2019 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 6,492 $ 738 $ — $ 7,230 $ 7,745 $ 596 $ — $ 8,341 Mortgage-Backed Securities – Commercial 182,823 8,357 — 191,180 186,316 2,983 (166) 189,133 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 481,109 14,924 — 496,033 660,777 4,113 (2,943) 661,947 Other Government-Sponsored Enterprises 100,996 2 — 100,998 1,000 — — 1,000 Obligations of States and Political Subdivisions 11,154 243 — 11,397 17,738 171 — 17,909 Corporate Securities 22,941 1,444 — 24,385 22,919 1,043 — 23,962 Total Securities Available for Sale $ 805,515 $ 25,708 $ — $ 831,223 $ 896,495 $ 8,906 $ (3,109) $ 902,292 Mortgage backed securities include mortgage backed obligations of U.S. Government agencies and obligations of U.S. Government-sponsored enterprises. These obligations have contractual maturities ranging from less than one year to approximately 30 years with lower anticipated lives to maturity due to prepayments. All mortgage backed securities contain a certain amount of risk related to the uncertainty of prepayments of the underlying mortgages. Interest rate changes have a direct impact upon prepayment speeds; therefore, First Commonwealth uses computer simulation models to test the average life and yield volatility of all mortgage backed securities under various interest rate scenarios to monitor the potential impact on earnings and interest rate risk positions. Expected maturities will differ from contractual maturities because issuers may have the right to call or repay obligations with or without call or prepayment penalties. Other fixed income securities within the portfolio also contain prepayment risk. The amortized cost and estimated fair value of debt securities available for sale at December 31, 2020, by contractual maturity, are shown below: Amortized Estimated (dollars in thousands) Due within 1 year $ 104,995 $ 105,015 Due after 1 but within 5 years 19,349 20,395 Due after 5 but within 10 years 10,747 11,370 Due after 10 years — — 135,091 136,780 Mortgage-Backed Securities (a) 670,424 694,443 Total Debt Securities $ 805,515 $ 831,223 (a) Mortgage Backed Securities include an amortized cost of $189.3 million and a fair value of $198.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $481.1 million and a fair value of $496.0 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac. Proceeds from sales of securities and gross gains (losses) realized on sales, calls and maturities of securities available for sale were as follows for the years ended December 31: 2020 2019 2018 (dollars in thousands) Proceeds from sales $ — $ 948 $ 15,939 Gross (losses) gains realized: Sales Transactions: Gross gains $ — $ — $ 4,719 Gross losses — (7) — — (7) 4,719 Maturities Gross gains 70 29 3,383 Gross losses — — — 70 29 3,383 Net gains $ 70 $ 22 $ 8,102 Gross gains from maturities recognized in 2020 were the result of calls on municipal securities. Gross losses on sales transactions recognized in 2019 were the result of the sale of one municipal security after its credit rating was withdrawn. Gross gains from maturities recognized in 2019 were the result of calls on municipal securities. Gross gains from sales transactions of $4.7 million were recognized in 2018 as a result of the sale of the remaining pooled trust preferred security portfolio. Gross gains from maturities of $3.4 million were recognized in 2018 as a result of successful auction calls on PreSTL XIV and PreSTL IX, two of our pooled trust preferred securities. Securities available for sale with an approximate fair value of $792.1 million and $584.8 million were pledged as of December 31, 2020 and 2019, respectively, to secure public deposits and for other purposes required or permitted by law. Securities Held to Maturity Below is an analysis of the amortized cost and fair values of debt securities held to maturity at December 31: 2020 2019 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 2,766 $ 138 $ — $ 2,904 $ 3,392 $ 57 $ — $ 3,449 Mortgage-Backed Securities – Commercial 36,799 1,441 — 38,240 51,291 18 (184) 51,125 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 277,351 5,389 (10) 282,730 229,667 1,377 (294) 230,750 Mortgage-Backed Securities – Commercial 9,737 344 — 10,081 12,081 67 — 12,148 Obligations of States and Political Subdivisions 34,391 705 — 35,096 40,092 554 — 40,646 Debt Securities Issued by Foreign Governments 800 — — 800 600 — — 600 Total Securities Held to Maturity $ 361,844 $ 8,017 $ (10) $ 369,851 $ 337,123 $ 2,073 $ (478) $ 338,718 The amortized cost and estimated fair value of debt securities held to maturity at December 31, 2020, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Amortized Estimated (dollars in thousands) Due within 1 year $ 2,500 $ 2,525 Due after 1 but within 5 years 7,669 7,742 Due after 5 but within 10 years 20,126 20,689 Due after 10 years 4,896 4,940 35,191 35,896 Mortgage-Backed Securities (a) 326,653 333,955 Total Debt Securities $ 361,844 $ 369,851 (a) Mortgage Backed Securities include an amortized cost of $39.6 million and a fair value of $41.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $287.1 million and a fair value of $292.8 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac. Securities held to maturity with an amortized cost of $228.1 million and $306.8 million were pledged as of December 31, 2020 and 2019, respectively, to secure public deposits for other purposes required or permitted by law. Other Investments As a member of the Federal Home Loan Bank ("FHLB"), First Commonwealth is required to purchase and hold stock in the FHLB to satisfy membership and borrowing requirements. The level of stock required to be held is dependent on the amount of First Commonwealth's mortgage related assets and outstanding borrowings with the FHLB. This stock is restricted in that it can only be sold to the FHLB or to another member institution, and all sales of FHLB stock must be at par. As a result of these restrictions, FHLB stock is unlike other investment securities insofar as there is no trading market for FHLB stock and the transfer price is determined by FHLB membership rules and not by market participants. As of December 31, 2020 and 2019, our FHLB stock totaled $10.6 million and $15.1 million, respectively and is included in “Other investments” on the Consolidated Statements of Financial Condition. FHLB stock is held as a long-term investment and its value is determined based on the ultimate recoverability of the par value. First Commonwealth evaluates impairment quarterly and has concluded that the par value of its investment in FHLB stock will be recovered. Accordingly, no impairment charge was recorded on these securities for the year ended December 31, 2020. At both December 31, 2020 and 2019, Other Investments also includes $1.7 million in equity securities. These securities do not have a readily determinable fair value and are carried at cost. For the years ended December 31, 2020 and 2019, there were no gains or losses recognized through earnings on equity securities. On a quarterly basis, management evaluates equity securities by reviewing research reports, analysts’ recommendations, credit rating changes, news stories, annual reports, regulatory filings, impact of interest rate changes and other relevant information. Impairment of Investment Securities On January 1, 2020, First Commonwealth adopted ASU 2016-13 Financial Instruments - Credit Losses (Topic 326), which requires estimated credit losses on held to maturity securities be recorded as an allowance for credit loss instead of a reduction in the amortized cost of the securities. Prior to the adoption of ASU 2016-13, credit related other-than-temporary impairment on debt securities was recognized in earnings while non-credit related other-than-temporary impairment on debt securities not expected to be sold was recognized in OCI. There were no estimated credit losses recorded during the year ended December 31, 2020. During the years ended December 31, 2019 and 2018, no other-than-temporary impairment charges were recognized. First Commonwealth utilizes the specific identification method to determine the net gain or loss on debt securities and the average cost method to determine the net gain or loss on equity securities. We review our investment portfolio on a quarterly basis for indications of impairment. For available for sale securities the review includes analyzing the financial condition and near-term prospects of the issuer, including any specific events which may influence the operations of the issuer and whether we are more likely than not to sell the security. We evaluate whether we are more likely than not to sell debt securities based upon our investment strategy for the particular type of security and our cash flow needs, liquidity position, capital adequacy, tax position and interest rate risk position. Held-to-maturity securities are evaluated for impairment on a quarterly basis using historical probability of default and loss given default information specific to the investment category. If this evaluation determines that credit losses exist an allowance for credit loss is recorded and included in earnings as a component of credit loss expense. The following table presents the gross unrealized losses and estimated fair values at December 31, 2020 for available for sale securities for which an allowance for credit losses has not been recorded and held to maturity securities by investment category and time frame for which the securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 3,755 (10) — — 3,755 (10) Total Securities $ 3,755 $ (10) $ — $ — $ 3,755 $ (10) At December 31, 2020, fixed income securities issued by U.S. Government-sponsored enterprises comprised 100% of total unrealized losses. All unrealized losses are a result of changes in market interest rates. At December 31, 2020, there were 2 debt securities in an unrealized loss position, all of which related to residential mortgage-backed securities with an unrealized loss of less than 12 months. There were no equity securities in an unrealized loss position at December 31, 2020. The following table presents the gross unrealized losses and estimated fair value at December 31, 2019 for both available for sale and held to maturity securities by investment category and time frame for which the securities had been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Commercial $ 54,501 $ (201) $ 16,365 $ (149) $ 70,866 $ (350) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 111,969 (436) 219,015 (2,801) 330,984 (3,237) Total Securities $ 166,470 $ (637) $ 235,380 $ (2,950) $ 401,850 $ (3,587) As of December 31, 2020, our corporate securities had an amortized cost and estimated fair value of $22.9 million and $24.4 million, respectively, and were comprised of debt for large regional banks. At December 31, 2019, these securities had an amortized cost of $22.9 million and estimated fair value of $24.0 million. When unrealized losses exist, management reviews each of the issuer’s asset quality, earnings trend and capital position, to determine whether the unrealized loss position is a result of credit losses. All interest payments on the corporate securities are being made as contractually required. There was no expected credit related impairment recognized on investment securities during the twelve months ended December 31, 2020. Prior to 2020, investment securities were evaluated for other-than-temporary impairment. During 2018, all of our pooled trust preferred collateralized debt obligations were liquidated either through a successful auction call or sale. Other-than-temporary impairment charges were recognized on the pooled trust preferred securities in 2008, 2009 and 2010. The following table provides a cumulative roll forward of credit losses recognized in earnings for the trust preferred securities for the years ended December 31: 2019 2018 (dollars in thousands) Balance, beginning (a) $ — $ 12,208 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — Increases in cash flows expected to be collected, recognized over the remaining life of the securities (b) — (223) Reduction for debt securities sold during the period — (9,164) Reduction for debt securities called during the period — (2,821) Balance, ending $ — $ — (a) The beginning balance represents credit related losses included in other-than-temporary impairment charges recognized on debt securities in prior periods. (b) Represents the increase in cash flows recognized either as principal payments or interest income during the period.

Loans and Allowance for Credit

Loans and Allowance for Credit Losses	12 Months Ended
	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Abstract]
Loans and Allowance for Credit Losses	Loans and Allowance for Credit Losses Loans are presented in the Consolidated Statements of Financial Condition net of deferred loan fees and costs, and discounts related to purchased loans. Net deferred fees were $6.0 million as of December 31, 2020 and net deferred costs were $2.8 million as of December 31, 2019 and discounts on purchased loans were $7.0 million and $8.5 million at December 31, 2020 and 2019, respectively. The following table provides outstanding balances related to each of our loan types as of December 31: 2020 2019 Total Loans Originated Loans Acquired Loans Total Loans (dollars in thousands) Commercial, financial, agricultural and other $ 1,555,986 $ 1,212,026 $ 29,827 $ 1,241,853 Time and demand 1,541,382 Commercial credit cards 14,604 Real estate construction 427,221 442,777 6,262 449,039 Residential real estate 1,750,592 1,415,808 265,554 1,681,362 Residential first lien 1,144,323 Residential junior lien/home equity 606,269 Commercial real estate 2,211,569 1,958,346 159,173 2,117,519 Multifamily 371,239 Nonowner occupied 1,421,151 Owner occupied 419,179 Loans to individuals 815,815 685,416 13,959 699,375 Automobile 712,800 Consumer credit cards 12,360 Consumer other 90,655 Total loans $ 6,761,183 $ 5,714,373 $ 474,775 $ 6,189,148 The above table reflects loan categories used in the calculation of the allowance for credit losses. With the adoption of CECL in 2020, eleven categories with similar risk characteristics were identified. The totals provided for 2019 reflect the categories used in 2019 under the incurred methodology. Commercial, financial, agricultural and other loans at December 31, 2020 includes $478.9 million in PPP loans for small businesses who meet the necessary eligibility requirements. PPP loans are 100% guaranteed by the SBA under the CARES Act and are forgivable, in whole or in part, if the proceeds are used for payroll and other permitted purposes in accordance with the PPP requirements. Because PPP loans are fully guaranteed by the SBA, there is no allowance for credit losses recognized for these loans. Although the Company believes that the majority of these loans will ultimately be forgiven by the SBA in accordance with the terms of the program, there could be risks and liability to the Company associated with participation in the program. First Commonwealth’s loan portfolio includes five primary loan categories. When calculating the allowance for credit losses these categories are classified into eleven portfolio segments. The composition of loans by portfolio segment includes; Commercial, financial, agricultural and other Time & Demand - Consists primarily of commercial and industrial loans. This category consists of loans that are typically cash flow dependent and therefore have different risk and loss characteristics than other commercial loans. Loans in this category include revolving and term structures with fixed and variable interest rates. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and economic conditions measured by GDP. Commercial Credit Cards - Consists of unsecured credit cards for commercial customers. These commercial credit cards have separate characteristics outside of normal commercial non-real estate loans, as they tend to have shorter overall duration. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and economic conditions measured by GDP. Real estate construction Includes both 1-4 family and commercial construction loans. The risk and loss characteristics of the construction category are different than other real estate secured categories due to the collateral being at various stages of completion. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and measures of completed construction projects. Residential real estate Residential first lien - Consists of loans with collateral of 1-4 family residencies with a senior lien position. The risk and loss characteristics are unique for this group because the collateral for these loans are the borrower’s primary residence. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and residential property values. Residential Junior Lien/Home Equity - Consists of loans with collateral of 1-4 family residencies with an open end line of credit or junior lien position. The junior lien position for the majority of these loans provides a higher risk of loss than other residential real estate loans. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and residential property values. Commercial real estate Multifamily - Consists of loans secured by commercial multifamily properties. Real estate related to rentals to consumers could provide unique risk and loss characteristics. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of commercial real estate values and rental vacancy. Nonowner Occupied - Consists of loans secured by commercial real estate non-owner occupied and provides different loss characteristics than other real estate categories. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and economic conditions measured by GDP. Owner Occupied - Consists of loans secured by commercial real estate owner occupied properties. The risk and loss characteristics of this category were considered different than other real estate categories because it is owner occupied and would impact the ability to conduct business. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of national unemployment and economic conditions measured by GDP. Loans to individuals Automobile - Consists of both direct and indirect loans with automobiles and recreational vehicles held as collateral. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of consumer sentiment and automobile retention value. Consumer Credit Cards – Consists of unsecured consumer credit cards The primary macroeconomic drivers for estimating credit losses for this category include forecasts of consumer sentiment and economic conditions measured by GDP. Other Consumer - Consists of lines of credit, student loans and other consumer loans, not secured by real estate or autos. The primary macroeconomic drivers for estimating credit losses for this category include forecasts of consumer sentiment and the level of household debt. The allowance for credit losses is calculated by pooling loans of similar credit risk characteristics and applying a discounted cash flow methodology after incorporating probability of default and loss given default estimates. Probability of default represents an estimate of the likelihood of default and loss given default measures the expected loss upon default. Inputs impacting the expected losses include a forecast of macroeconomic factors, using a weighted forecast from a nationally recognized firm. Our model incorporates a one-year forecast of macroeconomic factors, after which the factors revert back to the historical mean over a one-year period. The most significant macroeconomic factor used in estimating credit losses is the national unemployment rate. The forecasted value for national unemployment at December 31, 2020 was 6.68% and during the one-year forecast period it was projected to average 7.25%, with a peak of 7.48%. Credit Quality Information As part of the on-going monitoring of credit quality within the loan portfolio, the following credit worthiness categories are used in grading our commercial loans: Pass Acceptable levels of risk exist in the relationship. Includes all loans not classified as OAEM, substandard or doubtful. Other Assets Especially Mentioned (OAEM) Potential weaknesses that deserve management’s close attention. The potential weaknesses may result in deterioration of the repayment prospects or weaken the Bank’s credit position at some future date. The credit risk may be relatively minor, yet constitute an undesirable risk in light of the circumstances surrounding the specific credit. No loss of principal or interest is expected. Substandard Well-defined weakness or a weakness that jeopardizes the repayment of the debt. A loan may be classified as substandard as a result of deterioration of the borrower’s financial condition and repayment capacity. Loans for which repayment plans have not been met or collateral equity margins do not protect the Company may also be classified as substandard. Doubtful Loans with the characteristics of substandard loans with the added characteristic that collection or liquidation in full, on the basis of presently existing facts and conditions, is highly improbable. The Company’s internal creditworthiness grading system provides a measurement of credit risk based primarily on an evaluation of the borrower’s cash flow and collateral. Category ratings are reviewed each quarter, at which time management analyzes the results, as well as other external statistics and factors related to loan performance. The following tables represent our credit risk profile by creditworthiness category for the years ended December 31: 2020 Non-Pass Pass OAEM Substandard Doubtful Loss Total Non-Pass Total (dollars in thousands) Commercial, financial, agricultural and other $ 1,491,916 $ 48,233 $ 15,837 $ — $ — $ 64,070 $ 1,555,986 Time and demand 1,477,312 48,233 15,837 — — 64,070 1,541,382 Commercial credit cards 14,604 — — — — — 14,604 Real estate construction 426,663 504 54 — — 558 427,221 Residential real estate 1,740,992 1,902 7,698 — — 9,600 1,750,592 Residential first lien 1,138,409 1,780 4,134 — — 5,914 1,144,323 Residential junior lien/home equity 602,583 122 3,564 — — 3,686 606,269 Commercial real estate 1,983,258 175,995 52,316 — — 228,311 2,211,569 Multifamily 369,883 131 1,225 — — 1,356 371,239 Nonowner occupied 1,216,252 161,336 43,563 — — 204,899 1,421,151 Owner occupied 397,123 14,528 7,528 — — 22,056 419,179 Loans to individuals 815,541 — 274 — — 274 815,815 Automobile 712,539 — 261 — — 261 712,800 Consumer credit cards 12,360 — — — — — 12,360 Consumer other 90,642 — 13 — — 13 90,655 Total $ 6,458,370 $ 226,634 $ 76,179 $ — $ — $ 302,813 $ 6,761,183 2019 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Originated Loans Pass $ 1,171,363 $ 442,751 $ 1,406,845 $ 1,918,690 $ 685,108 $ 5,624,757 Non-Pass OAEM 29,359 26 475 13,533 — 43,393 Substandard 11,304 — 8,488 26,123 308 46,223 Doubtful — — — — — — Total Non-Pass 40,663 26 8,963 39,656 308 89,616 Total $ 1,212,026 $ 442,777 $ 1,415,808 $ 1,958,346 $ 685,416 $ 5,714,373 Acquired Loans Pass $ 27,696 $ 5,697 $ 262,630 $ 153,814 $ 13,947 $ 463,784 Non-Pass OAEM 2,009 565 537 2,072 — 5,183 Substandard 122 — 2,387 3,287 12 5,808 Doubtful — — — — — — Total Non-Pass 2,131 565 2,924 5,359 12 10,991 Total $ 29,827 $ 6,262 $ 265,554 $ 159,173 $ 13,959 $ 474,775 The following table summarizes the loan risk rating category by loan type including term loans on an amortized cost basis by origination year as of December 31, 2020: Term Loans Revolving Loans 2020 2019 2018 2017 2016 Prior Total (dollars in thousands) Time and demand $ 598,053 $ 193,601 $ 142,224 $ 72,277 $ 74,228 $ 83,313 $ 377,686 $ 1,541,382 Pass 597,405 189,834 140,473 63,137 68,007 65,418 353,038 1,477,312 OAEM 93 3,373 972 8,820 6,182 8,043 20,750 48,233 Substandard 555 394 779 320 39 9,852 3,898 15,837 Commercial credit cards — — — — — — 14,604 14,604 Pass — — — — — — 14,604 14,604 Real estate construction 150,493 133,195 104,167 34,803 389 1,009 3,165 427,221 Pass 150,493 133,195 104,167 34,803 389 709 2,907 426,663 OAEM — — — — — 246 258 504 Substandard — — — — — 54 — 54 Residential first lien 316,052 184,550 142,823 110,365 91,495 297,057 1,981 1,144,323 Pass 316,028 184,533 142,467 110,260 91,059 292,158 1,904 1,138,409 OAEM — — 83 — 100 1,520 77 1,780 Substandard 24 17 273 105 336 3,379 — 4,134 Residential junior lien/home equity 3,055 5,783 4,545 2,005 1,303 7,127 582,451 606,269 Pass 3,055 5,698 4,545 2,005 1,303 6,909 579,068 602,583 OAEM — — — — — 112 10 122 Substandard — 85 — — — 106 3,373 3,564 Multifamily 76,249 16,287 69,439 66,963 34,383 106,328 1,590 371,239 Pass 76,249 16,287 69,439 66,963 34,383 104,972 1,590 369,883 OAEM — — — — — 131 — 131 Substandard — — — — — 1,225 — 1,225 Nonowner occupied 105,861 199,280 161,018 214,915 217,883 518,052 4,142 1,421,151 Pass 105,861 190,301 139,643 181,659 175,148 419,900 3,740 1,216,252 OAEM — 8,979 21,375 26,339 37,762 66,752 129 161,336 Substandard — — — 6,917 4,973 31,400 273 43,563 Owner occupied 59,519 72,313 61,079 40,796 27,415 152,555 5,502 419,179 Pass 58,551 70,726 55,478 39,351 26,359 141,376 5,282 397,123 OAEM 968 684 4,736 1,421 114 6,572 33 14,528 Substandard — 903 865 24 942 4,607 187 7,528 Automobile 350,293 202,923 96,355 45,218 14,285 3,726 — 712,800 Pass 350,293 202,827 96,336 45,187 14,255 3,641 — 712,539 Substandard — 96 19 31 30 85 — 261 Consumer credit cards — — — — — — 12,360 12,360 Pass — — — — — — 12,360 12,360 Consumer other 7,814 14,464 10,752 1,965 711 6,383 48,566 90,655 Pass 7,814 14,464 10,752 1,965 711 6,373 48,563 90,642 Substandard — — — — — 10 3 13 Total $ 1,667,389 $ 1,022,396 $ 792,402 $ 589,307 $ 462,092 $ 1,175,550 $ 1,052,047 $ 6,761,183 Portfolio Risks The credit quality of our loan portfolio can potentially represent significant risk to our earnings, capital and liquidity. First Commonwealth devotes a substantial amount of resources managing this risk primarily through our credit administration department that develops and administers policies and procedures for underwriting, maintaining, monitoring and collecting loans. Credit administration is independent of lending departments and oversight is provided by the credit committee of the First Commonwealth Board of Directors. Total gross charge-offs for the years ended December 31, 2020 and 2019 were $19.3 million and $12.3 million, respectively. Age Analysis of Past Due Loans by Segment The following tables delineate the aging analysis of the recorded investments in past due loans as of December 31. Also included in these tables are loans that are 90 days or more past due and still accruing because they are well-secured and in the process of collection. 2020 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 146 $ 62 $ 112 $ 3,317 $ 3,637 $ 1,552,349 $ 1,555,986 Time and demand 97 28 23 3,317 3,465 1,537,917 1,541,382 Commercial credit cards 49 34 89 — 172 14,432 14,604 Real estate construction 936 — — 54 990 426,231 427,221 Residential real estate 3,883 1,492 769 6,824 12,968 1,737,624 1,750,592 Residential first lien 1,775 660 267 3,489 6,191 1,138,132 1,144,323 Residential junior lien/home equity 2,108 832 502 3,335 6,777 599,492 606,269 Commercial real estate 237 160 3 35,072 35,472 2,176,097 2,211,569 Multifamily — — — 460 460 370,779 371,239 Nonowner occupied 18 104 — 31,822 31,944 1,389,207 1,421,151 Owner occupied 219 56 3 2,790 3,068 416,111 419,179 Loans to individuals 2,870 852 639 274 4,635 811,180 815,815 Automobile 2,090 417 94 261 2,862 709,938 712,800 Consumer credit cards 52 39 123 — 214 12,146 12,360 Consumer other 728 396 422 13 1,559 89,096 90,655 Total $ 8,072 $ 2,566 $ 1,523 $ 45,541 $ 57,702 $ 6,703,481 $ 6,761,183 2019 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Originated Loans Commercial, financial, agricultural and other $ 391 $ 57 $ 140 $ 8,780 $ 9,368 $ 1,202,658 $ 1,212,026 Real estate construction 198 — 9 — 207 442,570 442,777 Residential real estate 3,757 749 736 6,646 11,888 1,403,920 1,415,808 Commercial real estate 227 114 — 6,609 6,950 1,951,396 1,958,346 Loans to individuals 4,070 1,020 931 307 6,328 679,088 685,416 Total $ 8,643 $ 1,940 $ 1,816 $ 22,342 $ 34,741 $ 5,679,632 $ 5,714,373 Acquired Loans Commercial, financial, agricultural and other $ 1 $ — $ 1 $ 74 $ 76 $ 29,751 $ 29,827 Real estate construction — — — — — 6,262 6,262 Residential real estate 304 207 221 1,949 2,681 262,873 265,554 Commercial real estate — 107 — 298 405 158,768 159,173 Loans to individuals 87 89 35 12 223 13,736 13,959 Total $ 392 $ 403 $ 257 $ 2,333 $ 3,385 $ 471,390 $ 474,775 Nonaccrual Loans The previous tables summarize nonaccrual loans by loan segment. The Company generally places loans on nonaccrual status when the full and timely collection of interest or principal becomes uncertain, when part of the principal balance has been charged off and no restructuring has occurred, or the loans reach a certain number of days past due. Generally, loans 90 days or more past due are placed on nonaccrual status, except for consumer loans which are placed in nonaccrual status at 150 days past due. When a loan is placed on nonaccrual, the accrued unpaid interest receivable is reversed against interest income and all future payments received are applied as a reduction to the loan principal. Generally, the loan is returned to accrual status when (a) all delinquent interest and principal become current under the terms of the loan agreement or (b) the loan is both well-secured and in the process of collection and collectability is no longer in doubt. Nonperforming Loans Management considers loans to be nonperforming when, based on current information and events, it is determined that the Company will not be able to collect all amounts due according to the loan contract, including scheduled interest payments. Nonperforming loans includes nonaccrual loans and all troubled debt restructured loans. When management identifies a loan as nonperforming, the credit loss is measured based on the present value of expected future cash flows, discounted at the loan’s effective interest rate, except when the sole source or repayment for the loan is the operation or liquidation of collateral. When the loan is collateral dependent, the appraised value less estimated cost to sell is utilized. If management determines the value of the loan is less than the recorded investment in the loan, a credit loss is recognized through an allowance or a charge-off to the allowance for credit losses. When the ultimate collectability of the total principal of a nonperforming loan is in doubt and the loan is on nonaccrual status, all payments are applied to principal, under the cost recovery method. When the ultimate collectability of the total principal of a nonperforming loan is not in doubt and the loan is on nonaccrual status, contractual interest is credited to interest income when received under the cash basis method. There was one nonperforming loan totaling $13 thousand held for sale at December 31, 2020 and no nonperforming loans held for sale as of December 31, 2019. There were no gains on nonperforming loans held for sale during the year ended December 31, 2020. Total gains of $0.4 million and $1.8 million were recognized on sales of nonperforming loans during the years ended December 31, 2019, and 2018 respectively. The following tables include the recorded investment and unpaid principal balance for nonperforming loans with the associated allowance amount, if applicable, as of December 31, 2020 and 2019. Also presented are the average recorded investment in nonperforming loans and the related amount of interest recognized while the loan was considered nonperforming for the years ended December 31, 2020, 2019 and 2018. Average balances are calculated based on month-end balances of the loans for the period reported and are included in the table below based on its period end allowance position. 2020 Recorded Unpaid Related Average Interest (dollars in thousands) With no related specific allowance recorded: Commercial, financial, agricultural and other $ 2,025 $ 2,725 $ 6,371 $ 80 Time and demand 2,025 2,725 6,371 80 Real estate construction 54 53 146 14 Residential real estate 10,939 13,258 11,913 335 Residential first lien 6,062 7,575 6,605 241 Residential junior lien/home equity 4,877 5,683 5,308 94 Commercial real estate 20,650 23,641 22,287 184 Multifamily 1 82 1 — Nonowner occupied 16,786 19,459 18,536 82 Owner occupied 3,863 4,100 3,750 102 Loans to individuals 418 447 470 13 Automobile 405 430 447 13 Consumer other 13 17 23 — Subtotal 34,086 40,124 41,187 626 With a specific allowance recorded: Commercial, financial, agricultural and other 4,210 9,377 1,268 1,544 3 Time and demand 4,210 9,377 1,268 1,544 3 Real estate construction — — — — — Residential real estate — — — — — Residential first lien — — — — — Residential junior lien/home equity — — — — — Commercial real estate 15,757 15,830 3,638 7,997 10 Multifamily 459 470 116 395 — Nonowner occupied 15,060 15,122 3,508 7,363 — Owner occupied 238 238 14 239 10 Loans to individuals — — — — — Automobile — — — — — Consumer other — — — — — Subtotal 19,967 25,207 4,906 9,541 13 Total $ 54,053 $ 65,331 $ 4,906 $ 50,728 $ 639 2019 Recorded Unpaid Related Average Interest (dollars in thousands) Originated Loans: With no related specific allowance recorded: Commercial, financial, agricultural and other $ 1,848 $ 6,997 $ 2,411 $ 66 Real estate construction — — — — Residential real estate 10,372 12,437 10,819 365 Commercial real estate 3,015 3,210 7,455 156 Loans to individuals 406 640 371 17 Subtotal 15,641 23,284 21,056 604 With a specific allowance recorded: Commercial, financial, agricultural and other 8,290 10,032 $ 1,580 4,110 77 Real estate construction — — — — — Residential real estate 474 498 1 241 — Commercial real estate 5,293 5,308 851 1,747 3 Loans to individuals — — — — — Subtotal 14,057 15,838 2,432 6,098 80 Total $ 29,698 $ 39,122 $ 2,432 $ 27,154 $ 684 Acquired Loans: With no related specific allowance recorded: Commercial, financial, agricultural and other $ 73 $ 73 $ 2,479 $ — Real estate construction — — — — Residential real estate 2,136 2,585 1,986 8 Commercial real estate 298 320 747 18 Loans to individuals 12 15 13 — Subtotal 2,519 2,993 5,225 26 With a specific allowance recorded: Commercial, financial, agricultural and other — — $ — — — Real estate construction — — — — — Residential real estate — — — — — Commercial real estate — — — — — Loans to individuals — — — — — Subtotal — — — — — Total $ 2,519 $ 2,993 $ — $ 5,225 $ 26 2018 Originated Acquired Average Interest Average Interest (dollars in thousands) With no related specific allowance recorded: Commercial, financial, agricultural and other $ 18,480 $ 602 $ 214 $ 10 Real estate construction — — — — Residential real estate 10,651 271 1,906 5 Commercial real estate 7,919 177 1,565 — Loans to individuals 310 11 16 — Subtotal 37,360 1,061 3,701 15 With a specific allowance recorded: Commercial, financial, agricultural and other 2,531 20 11 — Real estate construction — — — — Residential real estate 504 13 — — Commercial real estate 991 4 — — Loans to individuals — — — — Subtotal 4,026 37 11 — Total $ 41,386 $ 1,098 $ 3,712 $ 15 Unfunded commitments related to nonperforming loans were $0.2 million and $1.7 million at December 31, 2020 and 2019, respectively. After considering the collateral related to these commitments, a reserve of $26 thousand and $12 thousand was established for these off balance sheet exposures at December 31, 2020 and 2019, respectively. Troubled debt restructured loans are those loans whose terms have been renegotiated to provide a reduction or deferral of principal or interest as a result of the financial difficulties experienced by the borrower, who could not obtain comparable terms from alternate financing sources. Troubled debt restructured loans are considered to be nonperforming loans. In March 2020, the Company began offering short-term loan modifications to assist borrowers during the COVID-19 national emergency. These modifications typically provide for the deferral of both principal and interest for 90 days. The CARES Act, along with a joint agency statement issued by banking regulators, provides that short-term modifications, meeting certain criteria and in response to COVID-19, do not need to be accounted for as a troubled debt restructured loans. Additionally, short-term loan modifications that are not accounted for as a troubled debt restructured loan, in accordance with the CARES Act, would remain classified as current during the deferral period and therefore are not reflected in the past due loan tables provided on the prior page. During the year ended December 31, 2020, the Company granted approximately 6,800 short-term loan modifications to its customers with aggregate principal balances of $1.4 billion. Most of these deferrals were for a 90-day period, which expired before year end. As of December 31, 2020, the balance of loans in deferral status had fallen to $113.8 million. It is likely that some customers that are no longer in the deferral period will be granted an additional 90 day deferral in order to provide support for the continued impact of COVID-19. The decision to grant an additional forbearance will be credit driven and will be based on a complete evaluation of the customer's financial circumstances. The following table provides detail as to the total troubled debt restructured loans and total commitments outstanding on troubled debt restructured loans as of December 31: 2020 2019 2018 (dollars in thousands) Troubled debt restructured loans Accrual status $ 8,512 $ 7,542 $ 8,757 Nonaccrual status 14,740 6,037 11,761 Total $ 23,252 $ 13,579 $ 20,518 Commitments Letters of credit $ 60 $ 60 $ 60 Unused lines of credit 11 163 1,027 Total $ 71 $ 223 $ 1,087 The following tables provide detail, including specific reserve and reasons for modification, related to loans identified as troubled debt restructurings during the years ending December 31: 2020 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 4 $ — $ 629 $ 2,176 $ 2,805 $ 2,196 $ 636 Time and demand 4 — 629 2,176 2,805 2,196 636 Residential real estate 18 — 33 917 950 791 — Residential first lien 9 — 33 513 546 411 — Residential junior lien/home equity 9 — — 404 404 380 — Commercial real estate 5 — — 10,857 10,857 10,758 — Nonowner occupied 4 — — 10,289 10,289 10,263 — Owner occupied 1 — — 568 568 495 — Loans to individuals 14 — 114 148 262 224 — Automobile 14 $ — $ 114 $ 148 262 $ 224 $ — Total 41 $ — $ 776 $ 14,098 $ 14,874 $ 13,969 $ 636 2019 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 2 $ — $ — $ 156 $ 156 $ 154 $ — Residential real estate 20 17 204 965 1,186 1,059 — Commercial real estate 5 — 556 6,261 6,817 594 — Loans to individuals 11 — — 143 143 121 — Total 38 $ 17 $ 760 $ 7,525 $ 8,302 $ 1,928 $ — 2018 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 3 $ 74 $ — $ 8,250 $ 8,324 $ 6,104 $ — Residential real estate 37 242 241 1,316 1,799 1,638 — Commercial real estate 3 — — 1,016 1,016 975 — Loans to individuals 15 — 89 53 142 112 — Total 58 $ 316 $ 330 $ 10,635 $ 11,281 $ 8,829 $ — The troubled debt restructurings included in the above tables are also included in the nonperforming loan tables provided earlier in this footnote. Loans defined as modified due to a change in rate include loans that were modified for a change in rate as well as a reamortization of the principal and an extension of the maturity. For the years ended December 31, 2020, 2019 and 2018, $0.8 million, $0.8 million and $0.3 million, respectively, of total rate modifications represent loans with modifications to the rate as well as payment due to reamortization. For 2020, 2019 and 2018, the changes in loan balances between the pre-modification balance and post-modification balance are due to customer payments. In 2020, the change between the pre-modification and post-modification balance for commercial real estate loans is primarily due to the payoff of one large commercial relationship that restructured during the year. A troubled debt restructuring is considered to be in default when a restructured loan is 90 days or more past due. The following table provides information related to loans that were restructured within the past twelve months and that were considered to be in default during the year ending December 31: 2020 2019 2018 Number of Recorded Number of Recorded Number of Recorded (dollars in thousands) Residential real estate 1 $ 34 — $ — 1 $ 49 Residential junior lien/home equity 1 34 Loans to individuals 2 74 — — — — Automobile 2 74 Total 3 $ 108 — $ — 1 $ 49 The following tables provide detail related to the allowance for credit losses for the years ended December 31. 2020 Beginning balance Impact of adoption of CECL Charge-offs Recoveries Provision (credit) a Ending balance (dollars in thousands) Commercial, financial, agricultural and other $ 20,234 $ 1,478 $ (6,318) $ 314 $ 1,479 $ 17,187 Time and demand — 21,242 (6,220) 301 1,515 16,838 Commercial credit cards — 470 (98) 13 (36) 349 Real estate construction 2,558 562 — 26 4,820 7,966 Residential real estate 4,093 7,276 (1,040) 414 3,615 14,358 Residential first liens — 7,326 (550) 296 847 7,919 Residential junior liens/home equity — 4,043 (490) 118 2,768 6,439 Commercial real estate 19,768 (207) (4,939) 312 27,019 41,953 Multifamily — 1,647 — — 4,593 6,240 Nownowner occupied — 12,317 (4,678) 187 20,588 28,414 Owner occupied — 5,597 (261) 125 1,838 7,299 Loans to individuals 4,984 4,284 (6,953) 991 16,539 19,845 Automobile — 6,106 (3,954) 745 13,236 16,133 Consumer credit cards — 221 (595) 36 973 635 Consumer other — 2,941 (2,404) 210 2,330 3,077 Total $ 51,637 $ 13,393 $ (19,250) $ 2,057 $ 53,472 $ 101,309 a) The provision (credit) shown here excludes the provision for off-balance sheet credit exposure included in the income statement. December 31, 2020 Loans Ending balance Ending balance: individually evaluated for credit losses Ending balance: collectively evaluated for credit losses Ending balance Ending balance: individually evaluated for credit losses Ending balance: collectively evaluated for credit losses (dollars in thousands) Commercial, financial, agricultural and other $ 17,187 $ 1,268 $ 15,919 $ 1,555,986 $ 5,411 $ 1,550,575 Time and demand 16,838 1,268 15,570 1,541,382 5,411 1,535,971 Commercial credit cards 349 — 349 14,604 — 14,604 Real estate construction 7,966 — 7,966 427,221 — 427,221 Residential real estate 14,358 — 14,358 1,750,592 1,105 1,749,487 Residential first liens 7,919 — 7,919 1,144,323 528 1,143,795 Residential junior liens/home equity 6,439 — 6,439 606,269 577 605,692 Commercial real estate 41,953 3,638 38,315 2,211,569 34,947 2,176,622 Multifamily 6,240 116 6,124 371,239 459 370,780 Nownowner occupied 28,414 3,508 24,906 1,421,151 31,450 1,389,701 Owner occupied 7,299 14 7,285 419,179 3,038 416,141 Loans to individuals 19,845 — 19,845 815,815 — 815,815 Automobile 16,133 — 16,133 712,800 — 712,800 Consumer credit cards 635 — 635 12,360 — 12,360 Consumer other 3,077 — 3,077 90,655 — 90,655 Total $ 101,309 $ 4,906 $ 96,403 $ 6,761,183 $ 41,463 $ 6,719,720 2019 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Originated Loans: Beginning balance $ 19,235 $ 2,002 $ 3,934 $ 18,382 $ 4,033 $ 47,586 Charge-offs (2,667) — (986) (632) (5,747) (10,032) Recoveries 245 158 246 189 611 1,449 Provision (credit) 3,408 398 897 1,792 6,087 12,582 Ending balance 20,221 2,558 4,091 19,731 4,984 51,585 Acquired Loans: Beginning balance $ 139 $ — $ 35 $ 4 $ — $ 178 Charge-offs (726) — (56) (1,376) (84) (2,242) Recoveries 81 — 69 — 15 165 Provision (credit) 519 — (46) 1,409 69 1,951 Ending balance 13 — 2 37 — 52 Total ending balance $ 20,234 $ 2,558 $ 4,093 $ 19,768 $ 4,984 $ 51,637 Ending balance: individually evaluated for impairment $ 1,580 $ — $ 1 $ 851 $ — $ 2,432 Ending balance: collectively evaluated for impairment 18,654 2,558 4,092 18,917 4,984 49,205 Loans: Ending balance 1,241,853 449,039 1,681,362 2,117,519 699,375 6,189,148 Ending balance: individually evaluated for impairment 9,246 — 1,741 6,846 — 17,833 Ending balance: collectively evaluated for impairment 1,232,607 449,039 1,679,621 2,110,673 699,375 6,171,315 2018 Commercial, Real estate Resident

Commitments and Letters of Cred

Commitments and Letters of Credit	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Letters of Credit	Commitments and Letters of Credit First Commonwealth is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financial needs of its customers. These financial instruments include commitments to extend credit, standby letters of credit and commercial letters of credit. Those instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the Consolidated Statements of Financial Condition. First Commonwealth’s exposure to credit loss in the event of nonperformance by the other party of the financial instrument for commitments to extend credit, standby letters of credit and commercial letters of credit is represented by the contract or notional amount of those instruments. First Commonwealth uses the same credit policies for underwriting all loans, including these commitments and conditional obligations. As of December 31, 2020 and 2019, First Commonwealth did not own or trade other financial instruments with significant off-balance sheet risk including derivatives such as futures, forwards, option contracts and the like, although such instruments may be appropriate to use in the future to manage interest rate risk. See Note 7, “Derivatives,” for a description of interest rate derivatives entered into by First Commonwealth. Standby letters of credit and commercial letters of credit are conditional commitments issued by First Commonwealth to guarantee the performance of a customer to a third party. The contract or notional amount of these instruments reflects the maximum amount of future payments that First Commonwealth could be required to pay under the guarantees if there were a total default by the guaranteed parties, without consideration for possible recoveries under recourse provisions or from collateral held or pledged. In addition, many of these commitments are expected to expire without being drawn upon; therefore, the total commitment amounts do not necessarily represent future cash requirements. The following table identifies the notional amount of those instruments at December 31: 2020 2019 (dollars in thousands) Financial instruments whose contract amounts represent credit risk: Commitments to extend credit $ 2,097,628 $ 1,981,275 Financial standby letters of credit 15,988 16,630 Performance standby letters of credit 16,864 23,293 Commercial letters of credit 783 783 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. First Commonwealth evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by First Commonwealth upon extension of credit, is based on management’s credit evaluation of the counterparty. Collateral that is held varies but may include accounts receivable, inventory, property, plant and equipment, and residential and income-producing commercial properties. The notional amounts outstanding at December 31, 2020 include amounts issued in 2020 of $2.6 million in financial standby letters of credit and $0.3 million in performance standby letters of credit. There were no commercial letters of credit issued during 2020. A liability of $0.1 million has been recorded as of December 31, 2020 and 2019, which represents the estimated fair value of letters of credit issued. The fair value of letters of credit is estimated based on the unrecognized portion of fees received at the time the commitment was issued. Unused commitments and letters of credit provide exposure to future credit loss in the event of nonperformance by the borrower or guaranteed parties. Management’s evaluation of the credit risk in these commitments resulted in the recording of a liability of $7.4 million and $4.5 million as of December 31, 2020 and 2019, respectively. This liability is reflected in “ Other liabilities ” in the Consolidated Statements of Financial Condition. The credit risk evaluation incorporates the expected loss percentage calculated for comparable loan categories as part of the allowance for credit losses for loans.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises, Equipment and Lease Commitments Premises and Equipment Premises and equipment are described as follows: Estimated Useful Life 2020 2019 (dollars in thousands) Land Indefinite $ 15,441 $ 15,446 Buildings and improvements 10-50 years 77,003 76,965 Operating lease right of use asset 1-25 years 48,642 52,114 Leasehold improvements 5-40 years 35,347 37,716 Furniture and equipment 3-7 years 73,150 71,548 Software 3-7 years 41,681 40,399 Subtotal 291,264 294,188 Less accumulated depreciation and amortization 165,747 156,920 Total premises and equipment, net $ 125,517 $ 137,268 Depreciation related to premises and equipment included in noninterest expense for the years ended December 31, 2020, 2019 and 2018 amounted to $10.9 million, $10.5 million and $9.5 million, respectively. Amortization of lease right-of-use assets totaled $2.6 million in 2020 and $3.5 million in 2019. At December 31, 2020, $2.6 million in premise and equipment assets are considered available for sale as a result of the branch consolidation initiative. Lease Commitments On January 1, 2019, the Company adopted ASU 2016-02 “Leases” (Topic 842) and all subsequent ASUs that modified Topic 842 using the transition option provided in ASU 2018-11, which provides for the modified retrospective approach. Under this approach, comparative periods were not restated and no cumulative effect adjustment to the opening balance of retained earnings was required. First Commonwealth has elected to apply certain practical expedients provided under the standard including (i) to not apply the requirements in the new standard to short-term leases (ii) to not reassess the lease classification for any expired or existing lease (iii) to account for lease and non-lease components separately (iv) to not reassess initial direct costs for any existing leases. The impact of this standard primarily relates to operating leases of certain real estate properties, primarily certain branch and ATM locations and office space. First Commonwealth has no material leasing arrangements for which it is the lessor of property or equipment. Adoption of this standard resulted in the Company recognizing an ROU asset of $38.5 million and a lease liability of $41.8 million on January 1, 2019. The following table represents the lease costs and other lease information for the years ended December 31. 2020 2019 (dollars in thousands) Balance sheet: Operating lease asset classified as premises and equipment $ 42,617 $ 48,642 Operating lease liability classified as other liabilities 46,819 52,894 Income statement: Operating lease cost classified as occupancy and equipment expense $ 5,930 $ 5,328 Weighted average lease term, in years 14.83 15.27 Weighted average discount rate 3.42 % 3.43 % Operating cash flows $ 5,979 $ 4,656 The ROU assets and lease liabilities are impacted by the length of the lease term and the discount rate used to present value the minimum lease payments. First Commonwealth's lease agreements often include one or more options to renew at the Company's discretion. If we consider the renewal option to be reasonably certain, we include the extended term in the calculation of the ROU asset and lease liability. First Commonwealth uses incremental borrowing rates when calculating the lease liability because the rate implicit in the lease is not readily determinable. The incremental borrowing rate used by First Commonwealth is an amortizing loan rate obtained from the Federal Home Loan Bank ("FHLB") of Pittsburgh. This rate is consistent with a collateralized borrowing rate and is available for terms similar to the lease payment schedules. In July 2020, the Company announced the consolidation of 29 branch locations, including 12 leased locations, into nearby offices prior to December 31, 2020. As a result, during the third quarter, the Company paid $0.7 million in lease termination fees and decreased the ROU asset and lease liability by $3.8 million and $3.6 million, respectively. The following table reconciles future minimum lease payments due under non-cancelable operating leases (those amounts subject to recognition) to the lease liability a s of December 31, 2020 (dollars in thousands): For the twelve months ended 2021 $ 4,765 2022 4,653 2023 4,533 2024 4,399 2025 4,174 Thereafter 38,325 Total future minimum lease payments 60,849 Less remaining imputed interest 14,030 Operating lease liability $ 46,819 Rent expense, net of rental income, for all operating leases totaled $6.7 million in 2020, $4.9 million in 2019 and $4.1 million in 2018 . Rent expense includes amounts related to items that are not included in the determination of lease right-of-use assets

Goodwill and Other Amortizing I

Goodwill and Other Amortizing Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill Disclosure [Abstract]
Goodwill and Other Amortizing Intangible Assets	Goodwill and Other Intangible Assets FASB ASC Topic 350-20, “Intangibles—Goodwill and Other,” requires an annual valuation of the fair value of a reporting unit that has goodwill and a comparison of the fair value to the book value of equity to determine whether the goodwill has been impaired. Goodwill is also required to be tested on an interim basis if an event or circumstance indicates that it is more likely than not that an impairment loss has been incurred. When circumstances indicate that it is more likely than not that fair value is less than carrying value, a triggering event has occurred and a quantitative impairment test would be performed. We consider First Commonwealth to be one reporting unit. The carrying amount of goodwill as of December 31, 2020 and 2019 was $303.3 million. No impairment charges on goodwill or other intangible assets were incurred in 2020, 2019 or 2018. We test goodwill for impairment as of November 30th each year and again at any quarter-end if any material events occur during a quarter that may affect goodwill. As of December 31, 2020, goodwill was not considered impaired; however, changing economic conditions that may adversely affect our performance, the fair value of our assets and liabilities, or our stock price could result in impairment, which could adversely affect earnings in future periods. Management will continue to monitor events that could impact this conclusion in the future. FASB ASC Topic 350, “Intangibles—Other,” also requires that an acquired intangible asset be separately recognized if the benefit of the intangible asset is obtained through contractual or other legal rights, or if the asset can be sold, transferred, licensed, rented or exchanged, regardless of the acquirer’s intent to do so. The following table summarizes other intangible assets: Gross Accumulated Net (dollars in thousands) December 31, 2020 Customer deposit intangibles $ 22,573 $ (11,653) $ 10,920 Customer list intangible 2,283 (1,570) 713 Total other intangible assets $ 24,856 $ (13,223) $ 11,633 December 31, 2019 Customer deposit intangibles $ 25,843 $ (11,760) $ 14,083 Customer list intangible 2,283 (1,340) 943 Total other intangible assets $ 28,126 $ (13,100) $ 15,026 Core deposits are amortized over their expected lives using the present value of the benefit of the core deposits and straight-line methods of amortization. The core deposits have a remaining amortization period of 8.7 years and a weighted average amortization period of approximately 7.1 years. The customer list intangible represents the estimated value of the customer base for an insurance agency acquired in 2014 and the wealth management business acquired as part of the DCB acquisition in 2017. These amounts are amortized over their expected lives using expected cash flows based on retention of the customer base. The customer list intangible has a remaining amortization period of 8.7 years and a weighted average amortization period of 6.8 years. First Commonwealth recognized amortization expense on other intangible assets of $3.4 million, $3.2 million, and $3.1 million for the years ended December 31, 2020, 2019 and 2018, respectively. In addition to customer deposit intangibles and customer list intangibles, First Commonwealth has servicing rights on mortgage loans as well as certain commercial loans totaling $1.9 million and $1.3 million as of December 31, 2020 and 2019, respectively. These servicing rights relate to loans sold to third parties on which the Company retains servicing responsibilities. The Company recognized amortization expense on these servicing assets of $0.3 million and $0.2 million for the years ended December 31, 2020 and 2019, respectively. The following presents the estimated amortization expense of core deposit and customer list intangibles: Core Deposit Intangibles Customer List Intangible Total (dollars in thousands) 2021 $ 2,753 $ 193 $ 2,946 2022 2,343 159 2,502 2023 1,933 127 2,060 2024 1,522 97 1,619 2025 1,112 69 1,181 Thereafter 1,257 68 1,325 Total $ 10,920 $ 713 $ 11,633

Interest-Bearing Deposits

Interest-Bearing Deposits	12 Months Ended
	Dec. 31, 2020
Deposits [Abstract]
Interest-Bearing Deposits	Interest-Bearing Deposits Components of interest-bearing deposits at December 31 were as follows: 2020 2019 (dollars in thousands) Interest-bearing demand deposits $ 250,353 $ 254,981 Savings deposits 4,305,391 3,896,536 Time deposits 562,964 835,851 Total interest-bearing deposits $ 5,118,708 $ 4,987,368 Interest-bearing deposits at December 31, 2020 and 2019 include allocations from interest-bearing demand deposit accounts of $1.2 billion and $1.1 billion, respectively, into savings, which includes money market accounts. These allocations are based on a formula and were made in 2019 to reduce First Commonwealth’s reserve requirement in compliance with regulatory guidelines. Deposits totaling $0.7 million and $0.9 million at December 31, 2020 and 2019, respectively, were reclassified from deposits to loan due to their overdrawn status. Included in time deposits at December 31, 2020 and 2019 were certificates of deposit in denominations of $250 thousand or more of $93.1 million and $143.9 million, respectively. Interest expense related to certificates of deposit in denominations of $250 thousand or greater amounted to $2.0 million in 2020, $3.3 million in 2019 and $1.6 million in 2018. Included in time deposits at December 31, 2020, were certificates of deposit with the following scheduled maturities (dollars in thousands): 2021 $ 419,197 2022 88,783 2023 22,997 2024 16,222 2025 and thereafter 15,765 Total $ 562,964

Short-term Borrowings

Short-term Borrowings	12 Months Ended
	Dec. 31, 2020
Short-term Debt [Abstract]
Short-term Borrowings	Short-term Borrowings Short-term borrowings at December 31 were as follows: 2020 2019 2018 Ending Average Average Ending Average Average Ending Average Average (dollars in thousands) Federal funds purchased $ — $ 4,147 1.06 % $ — $ 8,069 2.53 % $ 11,000 $ 8,801 2.05 % Borrowings from FHLB — 28,252 1.54 136,200 278,930 2.62 565,000 467,594 2.12 Securities sold under agreements to repurchase 117,373 110,235 0.21 65,653 104,548 0.75 145,823 142,562 0.44 Total $ 117,373 $ 142,634 0.49 $ 201,853 $ 391,547 2.12 $ 721,823 $ 618,957 1.74 Maximum total at any month-end $ 248,471 $ 670,831 $ 811,026 Weighted average rate at year-end 0.10 % 1.41 % 2.17 % Interest expense on short-term borrowings for the years ended December 31 is detailed below: 2020 2019 2018 (dollars in thousands) Federal funds purchased $ 44 $ 204 $ 180 Borrowings from FHLB 434 7,313 9,929 Securities sold under agreements to repurchase 226 781 632 Total interest on short-term borrowings $ 704 $ 8,298 $ 10,741

Subordinated Debentures

Subordinated Debentures	12 Months Ended
	Dec. 31, 2020
Disclosure Subordinated Debentures [Abstract]
Subordinated Debentures	Subordinated Debentures Subordinated debentures outstanding at December 31 are as follows: 2020 2019 Due Amount Rate Amount Rate (dollars in thousands) Owed to: First Commonwealth Bank 06/01/2028 $ 49,314 4.875% until June 1, 2023, then LIBOR + 1.845% $ 49,222 4.875% until June 1, 2023, then LIBOR + 1.845% First Commonwealth Bank 06/01/2033 49,131 5.50% until June 1, 2028, 49,061 5.50% until June 1, 2028, First Commonwealth Capital Trust II 01/23/2034 30,929 LIBOR + 2.85 30,929 LIBOR + 2.85 First Commonwealth Capital Trust III 04/06/2034 41,238 LIBOR + 2.85 41,238 LIBOR + 2.85 Total $ 170,612 $ 170,450 On May 21, 2018, First Commonwealth Bank issued ten-year subordinated notes with an aggregate principal amount of $50.0 million and a fixed-to-floating rate of 4.88%. The rate remains fixed until June 1, 2023, then adjusts on a quarterly basis to LIBOR + 1.845%. The Bank may redeem the notes, beginning with the interest payment due on June 1, 2023, in whole or in part at a redemption price equal to 100% of the principal amount of the subordinated notes, plus accrued and unpaid interest to the date of redemption. Deferred issuance costs of $0.9 million are being amortized on a straight-line basis over the term of the notes. On May 21, 2018, First Commonwealth Bank also issued fifteen-year subordinated notes with an aggregate principal amount of $50.0 million and a fixed-to-floating rate of 5.50%. The rate remains fixed until June 1, 2028, then adjusts on a quarterly basis to LIBOR + 2.37%. The Bank may redeem the notes, beginning with the interest payment due on June 1, 2028, in whole or in part at a redemption price equal to 100% of the principal amount of the subordinated notes, plus accrued and unpaid interest to the date of redemption. Deferred issuance costs of $1.1 million are being amortized on a straight-line basis over the term of the notes. First Commonwealth currently has two trusts, First Commonwealth Capital Trust II and First Commonwealth Capital Trust III, of which 100% of the common equity is owned by First Commonwealth. The trusts were formed for the purpose of issuing company obligated mandatorily redeemable capital securities to third-party investors and investing the proceeds from the sale of the capital securities solely in junior subordinated debt securities (“subordinated debentures”) of First Commonwealth. The subordinated debentures held by each trust are the sole assets of the trust. Interest on the debentures issued to First Commonwealth Capital Trust III is paid quarterly at a floating rate of LIBOR + 2.85% which is reset quarterly. Subject to regulatory approval, First Commonwealth may redeem the debentures, in whole or in part, at its option on any interest payment date at a redemption price equal to 100% of the principal amount of the debentures, plus accrued and unpaid interest to the date of the redemption. Deferred issuance costs of $630 thousand are being amortized on a straight-line basis over the term of the securities. Interest on the debentures issued to First Commonwealth Capital Trust II is paid quarterly at a floating rate of LIBOR + 2.85%, which is reset quarterly. Subject to regulatory approval, First Commonwealth may redeem the debentures, in whole or in part, at its option at a redemption price equal to 100% of the principal amount of the debentures, plus accrued and unpaid interest to the date of the redemption. Deferred issuance costs of $471 thousand are being amortized on a straight-line basis over the term of the securities.

Other Long-term Debt

Other Long-term Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Other Long-term Debt	Other Long-term Debt Other long-term debt at December 31 follows: 2020 2019 Amount Weighted Amount Weighted (dollars in thousands) Borrowings from FHLB due: 2020 $ 659 3.84 % 2021 $ 50,685 2.32 % 50,685 2.32 2022 712 3.85 712 3.85 2023 739 3.86 739 3.86 2024 769 3.86 769 3.86 2025 799 3.86 Thereafter 2,554 3.74 3,353 3.77 Total $ 56,258 $ 56,917 The weighted average contractual rate reflects the rate due to creditors. There are no purchase accounting adjustments related to long-term debt in 2020 or 2019. Therefore, the weighted average effective rate of long-term debt is equal to the weighted average contractual rate of long-term debt. All of First Commonwealth’s Federal Home Loan Bank stock, along with an interest in mortgage loans and residential mortgage backed securities, has been pledged as collateral with the Federal Home Loan Bank of Pittsburgh. Capital securities included in total long-term debt on the Consolidated Statements of Financial Condition are excluded from the above, but are described in Note 15, “Subordinated Debentures.”

Fair Values of Assets and Liabi

Fair Values of Assets and Liabilities	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Values of Assets and Liabilities	Fair Values of Assets and Liabilities FASB ASC Topic 820, “Fair Value Measurements and Disclosures,” requires disclosures for non-financial assets and non-financial liabilities, except for items that are recognized or disclosed at fair value in the financial statements on a recurring basis (at least annually). All non-financial assets are included either as a separate line item on the Consolidated Statements of Financial Condition or in the “Other assets” category of the Consolidated Statements of Financial Condition. Currently, First Commonwealth does not have any non-financial liabilities to disclose. FASB ASC Topic 825, “Financial Instruments,” permits entities to irrevocably elect to measure select financial instruments and certain other items at fair value. The unrealized gains and losses are required to be included in earnings each reporting period for the items that fair value measurement is elected. First Commonwealth has elected not to measure any existing financial instruments at fair value under FASB ASC Topic 825; however, in the future we may elect to adopt this guidance for select financial instruments. In accordance with FASB ASC Topic 820, First Commonwealth groups financial assets and financial liabilities measured at fair value in three levels, based on the principal markets in which the assets and liabilities are transacted and the observability of the data points used to determine fair value. These levels are: • Level 1—Valuations for assets and liabilities traded in active exchange markets, such as the New York Stock Exchange (“NYSE”). Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities. • Level 2—Valuations for assets and liabilities traded in less active dealer or broker markets. Valuations are obtained for observable inputs for identical or comparable assets or liabilities from alternative pricing sources with reasonable levels of price transparency. Level 2 includes Obligations of U.S. Government securities issued by Agencies and Sponsored Enterprises, Obligations of States and Political Subdivisions, corporate securities, FHLB stock, loans held for sale, interest rate derivatives (including interest rate swaps, interest rate caps, interest rate collars and risk participation agreements), certain other real estate owned and certain nonperforming loans. Level 2 investment securities are valued by a recognized third party pricing service using observable inputs. The model used by the pricing service varies by asset class and incorporates available market, trade and bid information as well as cash flow information when applicable. Because many fixed-income investment securities do not trade on a daily basis, the model uses available information such as benchmark yield curves, benchmarking of like investment securities, sector groupings and matrix pricing. The model will also use processes such as an option-adjusted spread to assess the impact of interest rates and to develop prepayment estimates. Market inputs normally used in the pricing model include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including market research publications. Management validates the market values provided by the third party service by having another source price 100% of the securities on a monthly basis, monthly monitoring of variances from prior period pricing and, on a monthly basis, evaluating pricing changes compared to expectations based on changes in the financial markets. Other Investments include FHLB stock whose estimated fair value is based on its par value. Additional information on FHLB stock is provided in Note 8, “Investment Securities.” Loans held for sale include residential mortgage loans originated for sale in the secondary mortgage market. The estimated fair value for these loans was determined on the basis of rates obtained in the respective secondary market. Loans held for sale could also include the Small Business Administration guaranteed portion of small business loans. The estimated fair value of these loans is based on the contract with the third party investor. During the third quarter of 2020, the company announced the consolidation of 29 branch locations into nearby offices prior to December 31, 2020. As a result, 17 owned locations were moved to held for sale and are being carried at the lower of cost or fair value. Four of these locations are carried at fair value, determined by an independent market-based appraisal less estimated costs to sell, and are classified as Level 2. Interest rate derivatives are reported at estimated fair value utilizing Level 2 inputs and are included in "Other assets" and "Other liabilities" in the Consolidated Statements of Financial Condition. These consist of interest rate swaps where there is no significant deterioration in the counterparties' (loan customers') credit risk since origination of the interest rate swap as well as interest rate caps, interest rate collars and risk participation agreements. First Commonwealth values its interest rate swap and cap positions using a yield curve by taking market prices/rates for an appropriate set of instruments. The set of instruments currently used to determine the U.S. Dollar yield curve includes cash LIBOR rates from overnight to one year, Eurodollar futures contracts and swap rates from one year to thirty years. These yield curves determine the valuations of interest rate swaps. Interest rate derivatives are further described in Note 7, “Derivatives.” For purposes of potential valuation adjustments to our derivative positions, First Commonwealth evaluates the credit risk of its counterparties as well as our own credit risk. Accordingly, we have considered factors such as the likelihood of default, expected loss given default, net exposures and remaining contractual life, among other things, in determining if any estimated fair value adjustments related to credit risk are required. We review our counterparty exposure quarterly, and when necessary, appropriate adjustments are made to reflect the exposure. We also utilize this approach to estimate our own credit risk on derivative liability positions. In 2020 and 2019, we have not realized any losses due to a counterparty's inability to pay any net uncollateralized position. Interest rate derivatives also include interest rate forwards entered into to hedge residential mortgage loans held for sale and the related interest-rate lock commitments. This includes forward commitments to sell mortgage loans. The fair value of these derivative financial instruments are based on derivative market data inputs as of the valuation date and the underlying value of mortgage loans for rate lock commitments. In addition, the Company hedges foreign currency risk through the use of foreign exchange forward contracts. The fair value of foreign exchange forward contracts is based on the differential between the contract price and the market-based forward rate. The estimated fair value for other real estate owned included in Level 2 is determined by either an independent market based appraisal less estimated costs to sell or an executed sales agreement. • Level 3—Valuations for assets and liabilities that are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. If the inputs used to provide the valuation are unobservable and/or there is very little, if any, market activity for the security or similar securities, the securities would be considered Level 3 securities. Level 3 valuations incorporate certain assumptions and projections in determining the fair value assigned to such assets or liabilities. The assets included in Level 3 are non-marketable equity investments, certain interest rate derivatives, certain nonperforming loans and certain other real estate. The estimated fair value of the other investments included in Level 3 is based on carrying value as these securities do not have a readily determinable fair value. The estimated fair value of limited partnership investments included in Level 3 is based on par value. For interest rate derivatives included in Level 3, the fair value incorporates credit risk by considering such factors as likelihood of default and expected loss given default based on credit quality of the underlying counterparties (loan customers). In accordance with ASU 2011-4, the following table provides information related to quantitative inputs and assumptions used in Level 3 fair value measurements. Fair Value Valuation Technique Unobservable Inputs Range / (weighted December 31, 2020 Other Investments $ 1,670 Carrying Value N/A N/A Nonperforming Loans 798 (a) Gas Reserve study Discount rate 10.00% Gas per MMBTU $1.46 - $1.48 (b) Oil per BBL/d $36 - $36 (b) Limited Partnership Investments 6,619 Par Value N/A N/A December 31, 2019 Other Investments 1,670 Carrying Value N/A N/A Nonperforming Loans 884 (a) Gas Reserve study Discount rate 10.00% Gas per MMBTU $2.61 - $3.49 (b) Oil per BBL/d $47.09 - $53.14 (b) 2,239 (a) Discounted Cash Flow Discount Rate 3.84% - 9.50% Limited Partnership Investments 5,795 Par Value N/A N/A (a) the remainder of nonperforming loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation. (b) unobservable inputs are defined as follows: MMBTU—one million British thermal units; BBL/d—barrels per day. The discount rate is the significant unobservable input used in the fair value measurement of nonperforming loans. Significant increases in this rate would result in a decrease in the estimated fair value of the loans, while a decrease in this rate would result in a higher fair value measurement. Other unobservable inputs in the fair value measurement of nonperforming loans relate to gas, oil and natural gas prices. Increases in these prices would result in an increase in the estimated fair value of the loans, while a decrease in these prices would result in a lower fair value measurement. The tables below present the balances of assets and liabilities measured at fair value on a recurring basis at December 31: 2020 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 7,230 $ — $ 7,230 Mortgage-Backed Securities—Commercial — 191,180 — 191,180 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 496,033 — 496,033 Other Government-Sponsored Enterprises — 100,998 — 100,998 Obligations of States and Political Subdivisions — 11,397 — 11,397 Corporate Securities — 24,385 — 24,385 Total Securities Available for Sale — 831,223 — 831,223 Other Investments — 10,557 1,670 12,227 Loans Held for Sale — 33,436 — 33,436 Premises and Equipment — 442 — 442 Other Assets (a) — 54,362 6,619 60,981 Total Assets $ — $ 930,020 $ 8,289 $ 938,309 Other Liabilities (a) $ — $ 61,308 $ — $ 61,308 Total Liabilities $ — $ 61,308 $ — $ 61,308 (a) Hedging and non-hedging interest rate derivatives and limited partnership investments 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 8,341 $ — $ 8,341 Mortgage-Backed Securities—Commercial — 189,133 — 189,133 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 661,947 — 661,947 Other Government-Sponsored Enterprises — 1,000 — 1,000 Obligations of States and Political Subdivisions — 17,909 — 17,909 Corporate Securities — 23,962 — 23,962 Total Securities Available for Sale — 902,292 — 902,292 Other Investments — 15,091 1,670 16,761 Loans Held for Sale — 15,989 — 15,989 Other Assets (a) — 21,894 5,795 27,689 Total Assets $ — $ 955,266 $ 7,465 $ 962,731 Other Liabilities (a) $ — $ 21,469 $ — $ 21,469 Total Liabilities $ — $ 21,469 $ — $ 21,469 (a) Hedging and non-hedging interest rate derivatives and limited partnership investments The changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows for the year ended December 31, 2020: Other Investments Other Assets Total (dollars in thousands) Balance, beginning of year $ 1,670 $ 5,795 $ 7,465 Total gains or losses Included in earnings — — — Included in other comprehensive income — — — Purchases, issuances, sales, and settlements Purchases — 824 824 Issuances — — — Sales — — — Settlements — — — Transfers from Level 3 — — — Transfers into Level 3 — — — Balance, end of year $ 1,670 $ 6,619 $ 8,289 There are no gains or losses included in earnings for the period that are attributable to the change in realized gains (losses) relating to assets held at December 31, 2020. During the year ended December 31, 2020, there were no transfers between fair value Levels 1, 2 or 3. The changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows for the year ended December 31, 2019: Other Investments Other Assets Total (dollars in thousands) Balance, beginning of year $ 1,670 $ 2,696 $ 4,366 Total gains or losses Included in earnings — 198 198 Included in other comprehensive income — — — Purchases, issuances, sales, and settlements Purchases — 2,956 2,956 Issuances — — — Sales — — — Settlements — (55) (55) Transfers from Level 3 — — — Transfers into Level 3 — — — Balance, end of year $ 1,670 $ 5,795 $ 7,465 There are no gains or losses included in earnings for the period that are attributable to the change in realized gains (losses) relating to assets held at December 31, 2019. During the year ended December 31, 2019, there were no transfers between fair value Levels 1, 2 or 3. The tables below present the balances of assets measured at fair value on a nonrecurring basis at December 31 and total gains and losses realized on these assets during the year ended December 31: 2020 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Nonperforming loans $ — $ 35,543 $ 13,604 $ 49,147 $ (7,905) Other real estate owned — 1,319 — 1,319 (30) Total Assets $ — $ 36,862 $ 13,604 $ 50,466 $ (7,935) 2019 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Nonperforming loans $ — $ 12,267 $ 17,518 $ 29,785 $ (2,667) Other real estate owned — 2,608 — 2,608 (196) Total Assets $ — $ 14,875 $ 17,518 $ 32,393 $ (2,863) Nonperforming loans over $250 thousand are individually reviewed to determine the amount of each loan considered to be at risk of noncollection. The fair value for nonperfomring loans that are collateral based is determined by reviewing real property appraisals, equipment valuations, accounts receivable listings and other financial information. A discounted cash flow analysis is performed to determine fair value for nonperforming loans when an observable market price or a current appraisal is not available. For real estate secured loans, First Commonwealth’s loan policy requires updated appraisals be obtained at least every twelve months on all nonperforming loans with balances of $250 thousand and over. For real estate secured loans with balances under $250 thousand, we rely on broker price opinions. For non-real estate secured assets, the Company normally relies on third party valuations specific to the collateral type. The fair value for other real estate owned, determined by either an independent market based appraisal less estimated costs to sell or an executed sales agreement, is classified as Level 2. The fair value for other real estate owned determined using an internal valuation is classified as Level 3. Other real estate owned has a current carrying value of $1.2 million as of December 31, 2020 and consisted primarily of commercial real estate properties in Pennsylvania. We review whether events and circumstances subsequent to a transfer to other real estate owned have occurred that indicate the balance of those assets may not be recoverable. If events and circumstances indicate further impairment, we will record a charge to the extent that the carrying value of the assets exceed their fair values, less estimated costs to sell, as determined by valuation techniques appropriate in the circumstances. Certain other assets and liabilities, including goodwill, core deposit intangibles and customer list intangibles are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. Additional information related to this measurement is provided in Note 12 “Goodwill and Other Amortizing Intangible Assets.” There were no other assets or liabilities measured at fair value on a nonrecurring basis during 2020. FASB ASC Topic 825-10, “Transition Related to FSP FAS 107-1” and APB 28-1, “Interim Disclosures about Fair Value of Financial Instruments,” requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or nonrecurring basis. The methodologies for estimating the fair value of financial assets and financial liabilities that are measured at fair value on a recurring or nonrecurring basis are as discussed above. The methodologies for other financial assets and financial liabilities are discussed below. Cash and due from banks and interest bearing bank deposits : The carrying amounts for cash and due from banks and interest-bearing bank deposits approximate the estimated fair values of such assets. Securities : Fair values for available for sale and held to maturity securities are based on quoted market prices, if available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments. The carrying value of other investments, which includes FHLB stock, is considered a reasonable estimate of fair value. Loans held for sale : The estimated fair value of loans held for sale is based on market bids obtained from potential buyers. Loans: The fair values of all loans are estimated by discounting the estimated future cash flows using interest rates currently offered for loans with similar terms to borrowers of similar credit quality adjusted for past due and nonperforming loans. Off-balance sheet instruments : Many of First Commonwealth’s off-balance sheet instruments, primarily loan commitments and standby letters of credit, are expected to expire without being drawn upon; therefore, the commitment amounts do not necessarily represent future cash requirements. FASB ASC Topic 460, “Guarantees,” clarified that a guarantor is required to recognize, at the inception of a guarantee, a liability for the fair value of the obligation undertaken in issuing the guarantee. The carrying amount and estimated fair value for standby letters of credit was $0.1 million at both December 31, 2020 and 2019. See Note 10, “Commitments and Letters of Credit,” for additional information. Deposit liabilities : The estimated fair value of demand deposits, savings accounts and money market deposits is the amount payable on demand at the reporting date because of the customers' ability to withdraw funds immediately. The carrying value of variable rate time deposit accounts and certificates of deposit approximate the fair value at the report date. Also, fair values of fixed rate time deposits for both periods are estimated by discounting the future cash flows using interest rates currently being offered and a schedule of aggregated expected maturities. Short-term borrowings : The fair values of borrowings from the FHLB were estimated based on the estimated incremental borrowing rate for similar types of borrowings. The carrying amounts of other short-term borrowings, such as federal funds purchased and securities sold under agreement to repurchase, were used to approximate fair value due to the short-term nature of the borrowings. Subordinated debt and long-term debt : The fair value of long-term debt and subordinated debt is estimated by discounting the future cash flows using First Commonwealth’s estimate of the current market rate for similar types of borrowing arrangements. The following table presents carrying amounts and estimated fair values of First Commonwealth’s financial instruments at December 31: 2020 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 100,009 $ 100,009 $ 100,009 $ — $ — Interest-bearing deposits 256,572 256,572 256,572 — — Securities available for sale 831,223 831,223 — 831,223 — Securities held to maturity 361,844 369,851 — 369,851 — Other investments 12,227 12,227 — 10,557 1,670 Loans held for sale 33,436 33,436 — 33,436 — Loans 6,761,183 7,202,763 — 35,543 7,167,220 Financial liabilities Deposits 7,438,666 7,440,906 — 7,440,906 — Short-term borrowings 117,373 117,037 — 117,037 — Long-term debt 56,258 57,881 — 57,881 — Subordinated debt 170,612 165,665 — — 165,665 Capital lease obligation 6,385 6,385 — 6,385 — 2019 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 102,346 $ 102,346 $ 102,346 $ — $ — Interest-bearing deposits 19,510 19,510 19,510 — — Securities available for sale 902,292 902,292 — 902,292 — Securities held to maturity 337,123 338,718 — 338,718 — Other investments 16,761 16,761 — 15,091 1,670 Loans held for sale 15,989 15,989 — 15,989 — Loans 6,189,148 6,393,872 — 12,267 6,381,605 Financial liabilities Deposits 6,677,615 6,677,595 — 6,677,595 — Short-term borrowings 201,853 201,151 — 201,151 — Long-term debt 56,917 58,051 — 58,051 — Subordinated debt 170,450 171,772 — — 171,772 Capital lease obligation 6,815 6,815 — 6,815 —

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The income tax provision for the years ended December 31 is as follows: 2020 2019 2018 (dollars in thousands) Current tax provision: Federal $ 21,629 $ 22,942 $ 21,330 State 329 282 298 Total current tax provision 21,958 23,224 21,628 Deferred tax provision (benefit): Federal (5,070) 2,284 3,666 State (132) 8 (20) Total deferred tax provision (5,202) 2,292 3,646 Total tax provision $ 16,756 $ 25,516 $ 25,274 The statutory to effective tax rate reconciliation for the years ended December 31 is as follows: 2020 2019 2018 Amount % of Amount % of Amount % of (dollars in thousands) Tax at statutory rate $ 18,943 21 % $ 27,478 21 % $ 27,882 21 % Increase (decrease) resulting from: State income tax, net of federal benefit 155 — 229 — 220 — Income from bank owned life insurance (1,376) (1) (1,260) (1) (1,404) (1) Tax-exempt interest income, net (1,117) (1) (1,298) (1) (1,473) (1) Tax credits (44) — (7) — (5) — Enactment of federal tax reform — — — — (346) — Other 195 — 374 — 400 — Total tax provision $ 16,756 19 % $ 25,516 19 % $ 25,274 19 % The total tax provision for financial reporting differs from the amount computed by applying the statutory federal income tax rate to income before taxes. First Commonwealth ordinarily generates an annual effective tax rate that is less than the statutory rate of 21% due to benefits resulting from tax-exempt interest, income from bank owned life insurance, and tax benefits associated with low-income housing tax credits. The consistent level of tax benefits that reduce First Commonwealth’s tax rate below the statutory rate produced an annual effective tax rate of 19% for each of the years ended December 31, 2020, 2019 and 2018. On December 22, 2017, H.R.1, commonly known as the Tax Cuts and Jobs Act (the “Act”) was signed into law. The Act reduced the corporate federal tax rate from 35% to 21% effective January 1, 2018. As a result, we are required to re-measure, through income tax expense, our deferred tax assets and liabilities using the enacted rate at which we expected them to be recovered or settled. Also on December 22, 2017, the U.S. Securities and Exchange Commission (“SEC”) released Staff Accounting Bulletin No. 118 (“SAB 118”) to address any uncertainty or diversity of views in practice in accounting for the income tax effects of the Act in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete this accounting in the reporting period that includes the enactment date. SAB 118 allowed for a measurement period not to extend beyond one year from the Act’s enactment date to complete the necessary accounting. In accordance with SAB 118, the accounting for the income tax effects of the Act has been completed as of the year ended December 31, 2018. The completion of the accounting resulted in an immaterial change to the previously recorded re-measurement. The tax effects of temporary differences between the financial statement carrying amounts and the tax bases of assets and liabilities that represent significant portions of the deferred tax assets and liabilities at December 31 are presented below: 2020 2019 (dollars in thousands) Deferred tax assets: Lease liability $ 9,928 $ 11,203 Allowance for credit losses 21,483 10,937 Postretirement benefits other than pensions 242 275 Alternative minimum tax credit carryforward — 216 Net operating loss carryforward 385 2,017 Deferred compensation 1,723 1,720 Accrued interest on nonaccrual loans 644 710 Accrued incentives 2,182 2,185 Unfunded loan commitments & other reserves 1,576 964 Other 1,831 1,032 Total deferred tax assets 39,994 31,259 Deferred tax liabilities: Loan origination fees and costs (1,280) (626) Right of use asset $ (9,037) $ (10,302) Unrealized gain on securities available for sale (4,629) (1,386) Depreciation of assets (2,103) (1,470) Section 197 intangibles (540) (45) Other (424) (568) Total deferred tax liabilities (18,013) (14,397) Net deferred tax asset $ 21,981 $ 16,862 The Company has approximately $1.5 million of federal net operating losses which are subject to an annual limitation under IRC Section 382. The net operating losses expire in 2034 and the Company expects to utilize the losses prior to expiration. Management assesses all available positive and negative evidence to estimate if sufficient future taxable income will be generated to utilize the existing deferred tax assets. Based on our evaluation, as of December 31, 2020, management has determined that no valuation allowance is necessary for the deferred tax assets because it is more likely than not that these assets will be realized through future reversals of existing temporary differences and future taxable income. In accordance with FASB ASC Topic 740-10, “Accounting for Uncertainty in Income Taxes,” the Company has no material unrecognized tax benefits or accrued interest and penalties as of December 31, 2020. We do not expect the total amount of unrecognized tax benefits to significantly increase in the next twelve months. The Company records interest and penalties on unrecognized tax benefits as a component of noninterest expense. First Commonwealth is subject to routine audits of our tax returns by the Internal Revenue Service (“IRS”) as well as all states in which we conduct business. Generally, tax years prior to the year ended December 31, 2017 are no longer open to examination by federal and state taxing authorities.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans First Commonwealth has a savings plan pursuant to the provisions of section 401(k) of the Internal Revenue code. Effective January 1, 2013, a participating employee can receive a maximum matching contribution of 6% of their compensation. In addition, each participating employee may contribute up to 80% of their eligible compensation to the plan. The 401(k) plan expense was $3.9 million in 2020, $3.6 million in 2019, and $3.2 million in 2018. First Commonwealth maintains a Non-Qualified Deferred Compensation Plan ( “ NQDC Plan ” ) to provide deferred compensation for those employees who are in the top 7% of full-time employees, as determined on the basis of base compensation. The NQDC Plan provides participants whose maximum retirement contribution is limited by IRS rules to defer additional compensation. Participants in the NQDC Plan are eligible to defer (on a pre-tax basis) from 1% to 25% of their eligible Plan compensation. Participants are also eligible to defer all or a portion of the Annual Incentive Plan (on a pre-tax basis) from 10% to 100% of their annual cash incentive earned. There was no NQDC Plan expense in 2020, 2019 and 2018. Select employees from former acquisitions were covered by postretirement benefit plans which provide medical and life insurance coverage. The measurement date for these plans was December 31. Postretirement Benefits Other than Pensions from Prior Acquisitions Net periodic benefit cost of these plans for the years ended December 31, was as follows: 2020 2019 2018 (dollars in thousands) Service cost $ — $ — $ — Interest cost on projected benefit obligation 23 34 38 Amortization of transition obligation — — — Gain amortization (52) (60) (35) Net periodic benefit cost $ (29) $ (26) $ 3 The following table sets forth the change in the benefit obligation and plan assets as of December 31: 2020 2019 (dollars in thousands) Change in Benefit Obligation Benefit obligation at beginning of year $ 834 $ 883 Service cost — — Interest cost 23 34 Amendments 537 — Actuarial gain 102 61 Net benefits paid (124) (144) Benefit obligation at end of year 1,372 834 Change in Plan Assets Fair value of plan assets at beginning of year — — Actual return on plan assets — — Employer contributions 124 144 Net benefits paid (124) (144) Fair value of plan assets at end of year — — Funded Status at End of Year 1,372 834 Unrecognized prior service cost (537) — Unrecognized net gain 308 463 Amounts recognized in retained earnings $ 1,143 $ 1,297 As of December 31, the funded status of the plan is: 2020 2019 (dollars in thousands) Amounts Recognized in the Statement of Financial Condition as Other liabilities $ 1,372 $ 834 The following table sets forth the amounts recognized in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit costs as of December 31: 2020 2019 2018 (dollars in thousands) Amounts recognized in accumulated other comprehensive income, net of tax: Net (gain) loss $ (243) $ (366) $ (461) Prior service cost 424 — — Total $ 181 $ (366) $ (461) Weighted-average assumptions used to determine the benefit obligation as of December 31 are as follows: 2020 2019 2018 Weighted-Average Assumptions Discount rate 1.83 % 2.88 % 4.11 % Health care cost trend: Initial 5.95 % 5.55 % 6.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2026 2025 2024 Weighted-average assumptions used to determine the net benefit costs as of December 31 are as follows: 2020 2019 2018 Weighted-Average Assumptions for Net Periodic Cost Discount rate 2.88 % 4.11 % 3.37 % Health care cost trend: Initial 5.55 % 6.00 % 6.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2025 2024 2023 Corridor 10.00 % 10.00 % 10.00 % Recognition period for gains and losses 10.9 12.1 12.1 The Medicare Prescription Drug, Improvement and Modernization Act of 2003 (the “Act”) introduced a prescription drug benefit under Medicare Part D and a federal subsidy to sponsors of retiree health care benefit plans that provide a prescription drug benefit that is at least actuarially equivalent to Medicare Part D. The postretirement plans of First Commonwealth are provided through insurance coverage; therefore, First Commonwealth will not receive a direct federal subsidy. The preceding measures of the accumulated postretirement benefit cost assume that First Commonwealth will not receive the subsidy due to the relatively small number of retirees. The health care cost trend rate assumption can have a significant impact on the amounts reported for this plan. A one-percentage-point change in assumed health care cost trend rates would have the following effects: One-Percentage- One-Percentage- (dollars in thousands) Effect on postretirement benefit obligation $ 30 $ (29) Effect on total of service and interest cost components 1 — As of December 31, 2020, the projected benefit payments for the next ten years are as follows: Projected Benefit (dollars in thousands) 2021 $ 165 2022 157 2023 147 2024 136 2025 124 2026 - 2030 455 The projected payments were calculated using the same assumptions as those used to calculate the benefit obligations included in this note. The estimated costs that will be amortized from accumulated other comprehensive income into net periodic cost for 2021 are as follows (dollars in thousands): Postretirement (dollars in thousands) Net gain $ (27) Prior service cost 76 Total $ 49

Incentive Compensation Plan

Incentive Compensation Plan	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Incentive Compensation Plan	Incentive Compensation PlanOn January 20, 2009, the Board of Directors of the Company adopted, with shareholder approval, the First Commonwealth Financial Corporation Incentive Compensation Plan. This plan allows for shares of common stock to be issued to employees, directors, and consultants of the Company and its subsidiaries as an incentive to aid in the financial success of the Company. The shares can be issued as options, stock appreciation rights, performance share or unit awards, dividend or dividend equivalent rights, stock awards, restricted stock awards, or other annual incentive awards. Up to 5,000,000 shares of stock can be awarded under this plan, of which 2,689,027 shares were still eligible for awards as of December 31, 2020. Restricted Stock The following provides detail on the restricted stock awards which were issued and outstanding in 2020, 2019 and 2018 in order to retain and attract key employees. The grant date fair value of the restricted stock awards is equal to the price of First Commonwealth’s common stock on grant date. Grant Date Shares issued Grant Price Vesting Date Number of Equal Vesting Periods February 20, 2020 95,300 $ 13.72 February 20, 2023 1 February 21, 2019 63,000 14.22 February 22, 2022 1 February 21, 2019 15,000 14.22 February 22, 2022 1 November 26, 2018 2,000 13.82 November 26, 2021 1 May 29, 2018 3,000 15.44 May 29, 2021 1 March 26, 2018 2,000 14.08 March 26, 2021 1 February 26, 2018 77,500 14.49 February 26, 2021 1 March 24, 2017 5,000 12.99 March 24, 2020 1 March 24, 2017 7,000 12.99 March 24, 2020 1 December 19, 2016 15,000 13.96 December 19, 2019 3 September 30, 2016 10,000 10.09 September 30, 2019 1 September 19, 2016 33,000 10.02 September 19, 2019 3 June 7, 2016 10,000 9.34 June 7, 2019 1 March 1, 2016 10,000 8.84 March 1, 2019 1 March 1, 2016 5,000 8.84 March 1, 2019 1 June 26, 2015 1,000 9.84 June 26, 2018 1 February 5, 2015 50,000 8.55 February 5, 2018 1 Compensation expense related to restricted stock was $2.9 million, $2.7 million and $2.6 million in 2020, 2019 and 2018, respectively. As of December 31, 2020, there was $3.2 million of unrecognized compensation cost related to unvested restricted stock awards granted. A summary of the status of First Commonwealth’s unvested service-based restricted stock awards as of December 31 and changes for the years ended on those dates is presented below: 2020 2019 2018 Shares Weighted Shares Weighted Shares Weighted Outstanding, beginning of the year 171,500 $ 14.27 137,500 $ 13.05 117,000 $ 9.99 Granted 95,300 13.72 78,000 14.22 84,500 14.50 Vested (12,000) — (41,000) 10.09 (54,000) 9.37 Forfeited (4,000) 13.85 (3,000) 14.40 (10,000) 9.34 Outstanding, end of the year 250,800 14.13 171,500 14.27 137,500 13.05 The following provides detail on restricted stock awards estimated to be granted on a performance award basis during 2020, 2019 and 2018. These plans were previously approved by the Board of Directors. Grant Date Target Share Award Performance Period (years) Award if threshold met Award if targets are met Award if superior met Award if threshold not achieved Vesting After Performance Period (years) Final vesting December 30, 2015 60,000 5 0 December 31, 2020 February 18, 2016 160,650 3 40 % 100 % 200 % — % 0 December 31, 2018 February 23, 2017 93,500 3 40 % 100 % 200 % — % 0 December 31, 2019 February 22, 2018 102,000 3 40 % 100 % 200 % — % 0 December 31, 2020 February 21, 2019 121,900 3 40 % 100 % 200 % — % 0 December 31, 2021 February 20, 2020 188,700 3 40 % 100 % 200 % — % 0 December 31, 2022 The following table summarizes the estimated unvested target share awards for the Plans as of December 31: 2020 2019 2018 Outstanding, beginning of the year 442,832 496,603 525,045 Granted 188,700 134,929 130,995 Issued (134,452) (188,700) (149,480) Forfeited — — (9,957) Outstanding, end of the year 497,080 442,832 496,603 The December 30, 2015 grant has a fair value of $9.18 based the closing stock price when the shares were granted. Based on a Monte Carlo simulation, the February 23, 2017 grant has a fair value of $13.29 per share for 75% of the grant and $15.09 per share for 25% of the grant, the February 22, 2018 grant has a fair value of $14.17 for 50% of the grant, $13.25 for 25% of the grant and $15.83 for the remaining 25% of the grant, the February 21, 2019 grant has a fair value of $14.22 for 50% of the grant, $16.62 for 25% of the grant and $13.07 for the remaining 25% of the grant and the February 20, 2020 grant has a fair value of $13.72 for 50% of the grant, $15.37 for 25% of the grant and $12.43 for the remaining 25% of the grant.

Contingent Liabilities

Contingent Liabilities	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities	Contingent Liabilities Legal proceedings First Commonwealth and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings in which claims for monetary damages are asserted. As of December 31, 2020, management, after consultation with legal counsel, does not anticipate that the aggregate ultimate liability arising out of litigation pending or threatened against First Commonwealth or its subsidiaries will be material to First Commonwealth’s consolidated financial position. On at least a quarterly basis, First Commonwealth assesses its liabilities and contingencies in connection with such legal proceedings. For those matters where it is probable that First Commonwealth will incur losses and the amounts of the losses can be reasonably estimated, First Commonwealth records an expense and corresponding liability in its consolidated financial statements. To the extent the pending or threatened litigation could result in exposure in excess of that liability, the amount of such excess is not currently estimable. Although not considered probable, the range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability (if any), is between $0 and $1 million. Although First Commonwealth does not believe that the outcome of pending litigation will be material to First Commonwealth’s consolidated financial position, it cannot rule out the possibility that such outcomes will be material to the consolidated results of operations and cash flows for a particular reporting period in the future. First Commonwealth Bank was named a defendant in an action that commenced on October 14, 2020 in the Court of Common Pleas of Allegheny County, Pennsylvania. The plaintiffs allege that the Bank violated the Pennsylvania Commercial Code by failing to provide accurate and complete notices of repossession and post-sale notices to certain Pennsylvania customers whose motor vehicles were repossessed and later sold at public sales. Plaintiffs seek to pursue the action as a statewide class action on behalf of themselves and other allegedly similarly situated defaulting borrowers who had their motor vehicles repossessed and seeks to recover statutory damages. The Bank intends to vigorously defend against the plaintiffs’ claims and any request for class certification. The plaintiffs have not made any formal or specific financial demand and due to the preliminary status of this case any possible loss cannot be reasonably estimated at this time and is not included in the range set forth in the preceding paragraph.

Revenue Recognition (Notes)

Revenue Recognition (Notes)	12 Months Ended
	Dec. 31, 2020
Revenue Recognition and Deferred Revenue [Abstract]
Revenue Recognition	Revenue Recognition On January 1, 2018, the Company adopted ASU No. 2014-09 “Revenue from Contracts with Customers” (Topic 606) and all subsequent ASUs that modified Topic 606. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, First Commonwealth will generally be required to use more judgment and make more estimates than under current guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The Company adopted ASC 606 using the modified retrospective method applied to all contracts not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts were not adjusted and continue to be reported in accordance with our historic accounting under Topic 605. The implementation of the new standard did not have a material impact on the measurement or recognition of revenue, therefore a cumulative effect adjustment to opening retained earnings was not necessary. In connection with the adoption of Topic 606, First Commonwealth is required to capitalize, and subsequently amortize into expense, certain incremental costs of obtaining a contract with a customer if these costs are expected to be recovered. The incremental costs of obtaining a contract are those costs that an entity incurs to obtain a contract with a customer that it would not have incurred if the contract had not been obtained, for example, sales commission. The Company utilizes the practical expedient which allows entities to immediately expense contract acquisition costs when the asset that would have resulted from capitalizing these costs would have been amortized in one year or less. Upon adoption of Topic 606, the Company did not capitalize any contract acquisition cost. The Company also evaluated whether it has any significant contract balances. A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration resulting in a contract receivable or before payment is due resulting in a contract asset. A contract liability balance is an entity’s obligation to transfer a service to a customer for which the Company has already received payment from the customer. First Commonwealth’s noninterest revenue streams are largely based on transactional activity, or standard month-end revenue accruals such as trust income which is based on month-end market values. Consideration is often received immediately or shortly after the Company satisfies its performance obligation and revenue is recognized. The Company does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of December 31, 2020 and 2019, the Company did not have any significant contract balances. Topic 606 does not apply to revenue associated with financial instruments, including revenue from loans and securities. In addition, certain noninterest income streams such as fees associated with derivatives are not in scope of the new guidance. Topic 606 is applicable to noninterest revenue streams such as trust income, service charges on deposits, insurance and retail brokerage commissions, card related interchange income and gain (loss) on sale of OREO. The recognition of these revenue streams did not change significantly upon adoption of Topic 606. Substantially all of the Company’s revenue is generated from contracts with customers. Noninterest revenue streams in-scope of Topic 606 are discussed below: Trust Income Trust income is primarily comprised of fees earned from the management and administration of trusts and other customer assets. The Company’s performance obligation is generally satisfied over time and the resulting fees are recognized monthly, based upon a tiered scale of market value of the assets under management at month-end. Payment is generally received a few days after month end through a direct charge to customers’ accounts. The Company does not earn performance-based incentives. Optional services such as financial planning or tax return preparation services are also available to trust customers. The Company’s performance obligation for these transactional-based services is generally satisfied and related revenue recognized, at a point in time. Payment is received shortly after services are rendered. Service Charges on Deposit Accounts Service charges on deposit accounts consist of fees earned from its deposit customers for transaction-based, account maintenance, overdraft services and account analysis fees. Transaction-based fees, which include services such as ATM use fees, stop payment fees, statement rendering and ACH fees, are recognized at the time the transaction is executed which is the point in time the Company fulfills the customer’s request. Monthly account maintenance fees are earned over the course of the month, representing the period over which the Company satisfies the performance obligation. Overdraft fees are recognized at the point in time that the overdraft occurs. The Company’s performance obligation for account analysis fees is generally satisfied, and the related revenue recognized, during the month the service is provided. Payment for service charges on deposit accounts is primarily received immediately or in the following month through a direct charge to customers’ accounts. Insurance and Retail Brokerage Commissions Insurance income primarily consists of commissions received from execution of personal, business and health insurance policies when acting as an agent on behalf of insurance carriers. The Company’s performance obligation is generally satisfied upon the issuance of the insurance policy. Because the Company’s contracts with the insurance carriers are generally cancellable by either party, with minimal notice, insurance commissions are recognized during the policy period as received. Also, the majority of insurance commissions are received on a monthly basis during the policy period, however some carriers pay the full annual commission to First Commonwealth at the time of policy issuance or renewal. In these cases, First Commonwealth would be required to refund any commissions it would not be entitled to as a result of cancelled or terminated policies. The Company has established a refund liability for the remaining term of the policies expected to be cancelled. The Company also receives incentive-based contingency fees from the insurance carriers. Contingency fee revenue, which totals approximately $0.5 million per year, is recognized as received due to the immaterial amount. Retail brokerage income primarily consists of commissions received on annuity and investment product sales through a third-party service provider. The Company’s performance obligation is generally satisfied upon the issuance of the annuity policy or the execution of an investment transaction. The Company does not earn a significant amount of trailer fees on annuity sales. However, after considering the factors impacting these trailer fees, such as the uncertainty of investor behavior and changes in the market value of assets, First Commonwealth determined that it would recognize trailing fees as received because it could not reasonably estimate an amount of future trailing commissions for which collection is probable. Commissions from the third-party service provider are received on a monthly basis based upon customer activity for the month. The fees are recognized monthly with a receivable until commissions are received from the third-party service provider the following month. Because the Company acts as an agent in arranging the relationship between the customer and the third-party service provider and does not control the services rendered to the customers, retail brokerage fees are presented net of related costs, including $3.0 million in commission expense as of December 31, 2020 and 2019. Card Related Interchange Income Card related interchange income is primarily comprised of debit and credit card income, ATM fees and merchant services income. Debit and credit card income is primarily comprised of interchange fees earned whenever the Company’s debit and credit cards are processed through card payment networks such as Mastercard. ATM fees are primarily generated when a Company cardholder uses a non-Company ATM or a non-Company cardholder uses a Company ATM. Merchant services income mainly represents fees charged to merchants to process their debit and credit card transactions, in addition to account management fees. Card related interchange income is recognized at the point in time as the customer transactions are settled. Other Income Other income includes service revenue from processing wire transfers, bill pay service, cashier’s checks, and other services. The Company’s performance obligation for these services are largely satisfied, and related revenue recognized, when the services are rendered or upon completion. Payment is typically received immediately or in the following month. Gains(losses) on sales of OREO First Commonwealth records a gain or loss from the sale of OREO when control of the property transfers to the buyer, which generally occurs at the time of an executed deed. When First Commonwealth finances the sale of OREO to the buyer, an assessment of whether the buyer is committed to perform their obligations under the contract is completed along with an evaluation of whether collectability of the transaction price is probable. Once these criteria are met, the OREO asset is derecognized and the gain or loss on sale is recorded upon transfer of control of the property to the buyer. In determining the gain or loss on the sale, First Commonwealth adjusts the transaction price and related gain(loss) on sale if a significant financing component is present. The following presents noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606 for the year ended December 31: 2020 2019 2018 (dollars in thousands) Noninterest Income In-scope of Topic 606: Trust income $ 9,101 $ 8,321 $ 7,901 Service charges on deposit accounts 16,387 18,926 18,175 Insurance and retail brokerage commissions 7,850 7,583 7,426 Card-related interchange income 23,966 21,677 20,187 Gain on sale of other loans and assets 967 1,062 982 Other income 3,675 3,837 3,708 Noninterest Income (in-scope of Topic 606) 61,946 61,406 58,379 Noninterest Income (out-of-scope of Topic 606) 32,530 24,079 30,258 Total Noninterest Income $ 94,476 $ 85,485 $ 88,637

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Some of First Commonwealth’s directors, executive officers, principal shareholders and their related interests had transactions with the subsidiary bank in the ordinary course of business. All deposit and loan transactions were made on substantially the same terms, such as collateral and interest rates, as those prevailing at the time for comparable transactions. In the opinion of management, these transactions do not involve more than the normal risk of collectability nor do they present other unfavorable features. It is anticipated that similar transactions will be entered into in the future. The following is an analysis of loans to related parties (dollars in thousands): December 31, 2019 $ 19,246 Advances 4,258 Repayments (3,931) December 31, 2020 $ 19,573

Regulatory Restrictions and Cap

Regulatory Restrictions and Capital Adequacy	12 Months Ended
	Dec. 31, 2020
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Regulatory Restrictions and Capital Adequacy	Regulatory Restrictions and Capital Adequacy The amount of funds available to the parent from its subsidiary bank is limited by restrictions imposed on all depository institutions by banking regulation that restricts and limits the payment of dividends and the ability of depository institutions to engage in transactions, including lending transactions and asset purchases, with affiliates. First Commonwealth and First Commonwealth Bank are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators which, if undertaken, could have a direct material effect on First Commonwealth’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, First Commonwealth and First Commonwealth Bank must meet specific capital guidelines that involve quantitative measures of First Commonwealth’s assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. First Commonwealth’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weighting and other factors. Effective January 1, 2015, First Commonwealth became subject to regulatory risk-based capital rules adopted by the federal banking agencies implementing Basel III. The capital rules require First Commonwealth to maintain the following minimum capital levels: • a minimum Tier I capital to risk-weighted assets of at least 6.0%, plus a capital conservation buffer of 2.5%, resulting in a required minimum ratio of 8.5% • a minimum Common Equity Tier 1 to risk weighted assets of at lest 4.5%, plus the capital conservation buffer of 2.5%, resulting in a required minimum ratio of 7%. • a minimum Total Capital to risk weighted assets of at least 8.0%, plus the 2.5% capital conservation buffer, resulting in a required minimum of 10.5% • a minimum Leverage ratio, which is Tier 1 capital to adjusted average assets, of 4.0% The capital conservation buffer may only include capital that qualifies as Common Equity Tier 1. The Basel III Rules also permit banking organizations with less than $15.0 billion in assets to retain, through a one-time election, the exclusion of accumulated other comprehensive income from regulatory capital. The Company elected to retain this treatment, which reduces the volatility of regulatory capital levels. During the second quarter of 2018, First Commonwealth Bank, the Company's banking subsidiary, issued $100 million in subordinated debt, which under regulatory rules qualifies as Tier II capital. This subordinated debt issuance increased the total risk-based capital ratio by 160 basis points. As of December 31, 2020 and 2019, First Commonwealth and First Commonwealth Bank met all capital adequacy requirements to which they are subject and were considered well-capitalized under the regulatory rules as set forth in the tables below: Actual Minimum Capital Required Required to be Considered Well Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2020 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 1,010,608 14.88 % $ 713,289 10.50 % $ 679,323 10.00 % First Commonwealth Bank 974,911 14.36 712,995 10.50 679,043 10.00 Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 827,231 12.18 % $ 577,424 8.50 % $ 543,458 8.00 % First Commonwealth Bank 791,568 11.66 577,186 8.50 543,234 8.00 Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 827,231 9.40 % $ 352,023 4.00 % $ 440,029 5.00 % First Commonwealth Bank 791,568 9.01 351,244 4.00 439,055 5.00 Common Equity Tier I to Risk Weighted Assets First Commonwealth Financial Corporation $ 757,231 11.15 % $ 475,526 7.00 % $ 441,560 6.50 % First Commonwealth Bank 791,568 11.66 475,330 7.00 441,378 6.50 Actual Minimum Capital Required Required to be Considered Well Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2019 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 954,991 14.26 % $ 703,370 10.50 % $ 669,877 10.00 % First Commonwealth Bank 913,863 13.67 702,006 10.50 668,577 10.00 Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 800,526 11.95 % $ 569,395 8.50 % $ 535,901 8.00 % First Commonwealth Bank 759,398 11.36 568,291 8.50 534,862 8.00 Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 800,526 10.17 % $ 314,963 4.00 % $ 393,704 5.00 % First Commonwealth Bank 759,398 9.66 314,338 4.00 392,922 5.00 Common Equity Tier I to Risk Weighted Assets First Commonwealth Financial Corporation $ 730,526 10.91 % $ 468,914 7.00 % $ 435,420 6.50 % First Commonwealth Bank 759,398 11.36 468,004 7.00 434,575 6.50

Capital

Capital	12 Months Ended
	Dec. 31, 2020
Disclosure Capital Additional Information [Abstract]
Capital	Capital At December 31, 2020, shareholders’ equity was $1.1 billion, an increase of $13.0 million from December 31, 2019. The increase was primarily the result of $73.4 million in net income, $1.8 million in treasury stock sales and an increase of $11.7 million in the fair value of available for sale investments. These increases were partially offset by $43.0 million of dividends paid to shareholders, $20.9 million of common stock repurchases and an $11.2 million charge related to the adoption of CECL. Cash dividends declared per common share were $0.44 and $0.40 for the years ended December 31, 2020 and 2019, respectively. As part of the Company's capital management, First Commonwealth's Board of Directors will periodically authorize stock repurchase plans. In 2018, First Commonwealth announced a $25.0 million common stock repurchase program. This program was completed prior to the end of 2018 and resulted in a total of 1,843,373 shares repurchased at an average price of $13.58. On March 4, 2019, a share repurchase program was authorized for up to $25.0 million in shares of the Company's common stock. This program completed prior to December 31, 2020, and resulted in the repurchase of 2,761,504 shares at an average price of $9.07. In January 2021, the Board of Directors authorized a new $25.0 million share repurchase program of the Company's common stock. First Commonwealth may suspend or discontinue the program at any time.

Condensed Financial Information

Condensed Financial Information of First Commonwealth Financial Corporation (parent company only)	12 Months Ended
	Dec. 31, 2020
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of First Commonwealth Financial Corporation (parent company only)	Condensed Financial Information of First Commonwealth Financial Corporation (parent company only) Statements of Financial Condition December 31, 2020 2019 (dollars in thousands) Assets Cash $ 34,427 $ 22,889 Loans 11 13 Investment in subsidiaries 1,108,801 1,086,844 Investment in unconsolidated subsidiary trusts 2,182 2,190 Investment in jointly-owned company 338 306 Premises and equipment, net 3,476 3,801 Receivable from subsidiaries — 4,750 Dividends receivable from subsidiaries 3,038 5,097 Other assets 7,307 6,924 Total assets $ 1,159,580 $ 1,132,814 Liabilities and Shareholders’ Equity Accrued expenses and other liabilities $ 18,796 $ 4,983 Subordinated debentures payable 72,167 72,167 Shareholders’ equity 1,068,617 1,055,664 Total liabilities and shareholders’ equity $ 1,159,580 $ 1,132,814 Statements of Income For the years ended December 31, 2020 2019 2018 (dollars in thousands) Interest and dividends $ 8 $ 8 $ 1 Dividends from subsidiaries 61,708 55,964 81,851 Interest expense (3,229) (3,735) (3,722) Other income 3 6 14 Operating expense (4,687) (4,525) (4,047) Income before taxes and equity in undistributed earnings of subsidiaries 53,803 47,718 74,097 Applicable income tax benefits 1,648 1,720 1,324 Income before equity in undistributed earnings of subsidiaries 55,451 49,438 75,421 Equity in undistributed earnings of subsidiaries 17,996 55,895 32,077 Net income $ 73,447 $ 105,333 $ 107,498 For the years ended December 31, Statements of Cash Flow 2020 2019 2018 (dollars in thousands) Operating Activities Net income $ 73,447 $ 105,333 $ 107,498 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 383 340 320 Net gains on sales of assets — (2) (7) Decrease (increase) in prepaid income taxes (317) 629 37 Undistributed equity in subsidiaries (17,996) (55,895) (32,077) Distribution from unconsolidated subsidiary — — 9,000 Other net 19,705 (2,957) (1,628) Net cash provided by operating activities 75,222 47,448 83,143 Investing Activities Net change in loans 1 1 3 Purchases of premises and equipment (20) (586) (87) Proceeds from sale of other assets — 2 7 Investment in subsidiaries — — (17,202) Net cash used in by investing activities (19) (583) (17,279) Financing Activities Dividends paid (42,982) (39,394) (34,849) Proceeds from reissuance of treasury stock 222 211 208 Purchase of treasury stock (20,905) (6,259) (26,189) Net cash used in financing activities (63,665) (45,442) (60,830) Net increase (decrease) in cash 11,538 1,423 5,034 Cash at beginning of year 22,889 21,466 16,432 Cash at end of year $ 34,427 $ 22,889 $ 21,466 Cash dividends declared per common share were $0.44 for 2020, $0.40 in 2019 and $0.35 in 2018. First Commonwealth Financial Corporation has an unsecured $20.0 million line of credit with another financial institution. As of December 31, 2020, there are no amounts outstanding on this line and we are in compliance with all debt covenants related to the line of credit.

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent EventOn January 25, 2021, the Board of Directors authorized a new $25.0 million share repurchase program of the Company’s common stock. Under the new program, management is authorized to repurchase shares through Rule 10b5-1 plans, open market purchases, privately negotiated transactions, block purchases or otherwise in a manner that is intended to comply with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934. First Commonwealth may suspend or discontinue the program at any time.

Statement of Accounting Polic_2

Statement of Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Business Combinations Policy [Policy Text Block]	Business Combinations Business combinations are accounted for by using the acquisition method of accounting. Under the acquisition method, identifiable assets acquired and liabilities assumed at the acquisition date are measured at their fair values as of that date, and are recognized separately from goodwill. The difference between the purchase price and the fair value of the net assets acquired is recorded as goodwill. Results of operations of the acquired entities are included in the consolidated statement of income from the date of acquisition. Acquisition costs are expensed when incurred.
General	General The following summary of accounting and reporting policies is presented to aid the reader in obtaining a better understanding of the consolidated financial statements of First Commonwealth Financial Corporation and its subsidiaries (“First Commonwealth”) contained in this report. First Commonwealth's subsidiaries include, First Commonwealth Bank ("FCB" or the "Bank"), First Commonwealth Insurance Agency, Inc. ("FCIA"), FRAMAL and First Commonwealth Financial Advisors, Inc ("FCFA"). The financial information is presented in accordance with generally accepted accounting principles and general practice for financial institutions in the United States of America. In preparing financial statements, management is required to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. In addition, these estimates and assumptions affect revenues and expenses in the financial statements and as such, actual results could differ from those estimates. Through its subsidiaries, which include a commercial bank and an insurance agency, First Commonwealth provides a full range of loan, deposit, trust, insurance and personal financial planning services primarily to individuals and small to middle market businesses in 26 counties in central and western Pennsylvania as well as throughout Ohio. First Commonwealth has determined that it has one business segment. First Commonwealth is subject to regulations of certain state and federal agencies. These regulatory agencies periodically examine First Commonwealth for adherence to laws and regulations.
Basis of Presentation	Basis of Presentation The accompanying Consolidated Financial Statements include the accounts of First Commonwealth previously defined above. All material intercompany transactions have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current period's presentation. Equity investments of less than a majority but at least 20% ownership are accounted for by the equity method and classified as “Other assets.” Earnings on these investments are reflected in “Other income” on the Consolidated Statements of Income, as appropriate, in the period earned.
Securities	Securities Debt securities that First Commonwealth has the positive intent and ability to hold to maturity are classified as securities held to maturity and are reported at amortized cost adjusted for amortization of premium and accretion of discount on a level yield basis. Debt and equity securities that are bought and held principally for the purpose of selling them in the near term are to be classified as trading securities and reported at fair value, with unrealized gains and losses included in earnings. Debt securities not classified as either held-to-maturity securities or trading securities are classified as securities available for sale and are reported at fair value, with unrealized gains and losses that are not related to impairment excluded from earnings and reported as a component of other comprehensive income, which is included in shareholders’ equity, net of deferred taxes. First Commonwealth has securities classified as held to maturity and available for sale and does not engage in trading activities. First Commonwealth utilizes the specific identification method to determine the net gain or loss on debt securities and the average cost method to determine the net gain or loss on the equity securities. First Commonwealth conducts a comprehensive review of the investment portfolio on a quarterly basis to evaluate for expected credit losses. When evaluating available-for-sale securities, management first considers whether we intend to sell the security, or if it is more likely than not that we will be required to sell the security before recovery of its amortized cost basis. If there is intent to sell, the security's amortized cost is written down to fair value through income. Otherwise, available-for-sale securities whose market values have fallen below their book value are evaluated at the issuer-specific level to determine if the decline in value is a result of credit losses. Issuer-specific securities include obligations of U.S. Government agencies and sponsored enterprises, single issue trust preferred securities, corporate debentures and obligations of states and political subdivisions. Further analysis of these securities includes a review of research reports, analysts’ recommendations, credit rating changes, news stories, annual reports, impact of interest rate changes and any other relevant information pertaining to the affected security. Any loss not determined to be a credit loss is recorded as a reduction to shareholders equity, through other comprehensive income. Held-to-maturity securities are evaluated for impairment on a quarterly basis using historical probability of default and loss given default information specific to the investment category. If this evaluation determines that credit losses exist an allowance for credit loss is recorded and included in earnings as a component of credit loss expense.
Financing Receivable, Held-for-sale [Policy Text Block]	Mortgage Loans Held for SaleCertain residential mortgage loans are originated for sale in the secondary mortgage loan market with the majority sold with servicing rights released. These loans are classified as loans held for sale and are carried at the estimated market value on an aggregate basis. Market value is determined on the basis of rates obtained in the respective secondary market for the type of loan held for sale. Loans are generally sold at a premium or discount from the carrying amount of the loan. Such premium or discount is recognized at the date of sale. Gain or loss on the sale of loans is recorded in non-interest income at the time consideration is received and all other criteria for sales treatment have been met.
Loans	Loans Loans are carried at the principal amount outstanding. Interest is accrued as earned. Loans held for sale are carried at the lower of cost or fair market value determined on an individual basis. First Commonwealth considers a loan to be past due and still accruing interest when payment of interest or principal is contractually past due but the loan is both well secured and in the process of collection. For installment, mortgage, term and other loans with amortizing payments that are scheduled monthly, 90 days past due is reached when four monthly payments are due and unpaid. For demand, time and other multi-payment obligations with payments scheduled other than monthly, delinquency status is calculated using number of days instead of number of payments. Revolving credit loans, including personal credit lines and home equity lines, are considered to be 90 days past due when the borrower has not made the minimum payment for four monthly cycles. A loan is placed in nonaccrual status when, based on current information and events, it is probable that First Commonwealth will be unable to fully collect principal or interest due according to the contractual terms of the loan. A loan is also placed in nonaccrual status when, based on regulatory definitions, the loan is maintained on a “cash basis” due to the weakened financial condition of the borrower. When a determination is made to place a loan in nonaccrual status, all accrued and unpaid interest is reversed. Nonaccrual loans are restored to accrual status when, based on a sustained period of repayment by the borrower in accordance with the contractual terms of the loan, First Commonwealth expects repayment of the remaining contractual principal and interest or when the loan otherwise becomes well-secured and in the process of collection. First Commonwealth considers a loan to be a troubled debt restructured loan when the loan terms have been renegotiated to provide a reduction or deferral of principal or interest as a result of the financial difficulties experienced by the borrower, who could not obtain comparable terms from alternate financing sources. Troubled debt restructured loans are considered to be nonperforming loans. A loan is considered to be nonperforming when, based on current information and events, it is expected that First Commonwealth will be unable to collect principal or interest that is due in accordance with contractual terms of the loan. Nonperforming loans include nonaccrual loans and troubled debt restructured loans. Loan impairment is measured based on the present value of expected cash flows discounted at the loan’s effective interest rate or, as a practical expedient, at the loan’s observable market price or the fair value of the collateral if the loan is collateral dependent. For loans other than those that First Commonwealth expects repayment through liquidation of the collateral, when the remaining recorded investment in the loan is less than or equal to the present value of the expected cash flows, income is applied as a reduction to loan principal rather than interest income. Loans deemed uncollectible are charged off through the allowance for credit losses. Factors considered in assessing ultimate collectability include past due status, financial condition of the borrower, collateral values and debt covenants including secondary sources of repayment by guarantors. Payments received on previously charged off loans are recorded as recoveries in the allowance for credit losses. Acquired loans are recorded at estimated fair value on the date of acquisition with no carryover of the related allowance for credit losses. The fair value of acquired loans is determined by estimating the principal and interest cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. The estimated fair value considers factors such as loan term, internal risk rating, delinquency status, prepayment rates, estimated value of the underlying collateral and the current interest rate environment.
Loan Fees	Loan Fees Loan origination and commitment fees, net of associated direct costs, are deferred and the net amount is amortized as an adjustment to the related loan yield on the interest method, generally over the contractual life of the related loans or commitments.
Other Real Estate Owned	Other Real Estate OwnedReal estate, other than bank premises, is recorded at fair value less estimated selling costs at the time of acquisition.   After that time, other real estate is carried at the lower of cost or fair value less estimated costs to sell. Fair value is determined based on an independent appraisal. Expenses related to holding the property and rental income earned on the property are generally reflected in earnings in the current period. Depreciation is not recorded on the other real estate owned properties.
Allowance for Credit Losses	Allowance for Credit Losses for Loans On January 1, 2020, First Commonwealth adopted ASU 2016-13 Financial Instruments - Credit Losses ("Topic 326"), which replaces the incurred loss methodology for determining our allowance for credit losses and related provision for credit losses with an expected loss methodology that is referred to as the Current Expected Credit Loss ("CECL") model. The measurement of expected credit losses under the CECL methodology is applicable to financial assets measured at amortized cost, including our loans. We adopted ASU 2016-13 using the modified retrospective method for all financial assets measured at amortized cost and off-balance sheet credit exposures and recognized a cumulative effect adjustment reducing retained earnings by $11.2 million, net of tax. First Commonwealth made the accounting policy election to exclude accrued interest from the allowance for credit loss calculation because these balances are written off or reversed when a loan is placed in non-accrual status. In connection with our adoption of ASU 2016-13, we made changes to our loan portfolio segments, as compared to loan segments under the incurred model, to align with the methodology applied in determining the allowance under CECL. Refer to Note 9, " Loans and Allowance for Credit Losses" for further discussion of these portfolio segments. Under CECL, the allowance for credit losses is calculated by pooling loans of similar credit risk characteristics and applying a discounted cash flow methodology after incorporating probability of default and loss given default estimates. Probability of default represents an estimate of the likelihood of default and loss given default measures the expected loss upon default. Inputs impacting the expected losses includes a forecast of macroeconomic factors, using a weighted forecast from a nationally recognized firm. Our model incorporates a one-year forecast of macroeconomic factors, after which the factors revert back to the historical mean over a one-year period. Results for reporting periods beginning after January 1, 2020 are presented under ASU 2016-13 while prior period amounts continue to be reported in accordance with previously applicable GAAP. Prior to January 1, 2020, the allowance for credit losses was estimated based on managements assessment of probable estimated losses. In addition to loan category, the major loan classifications used in the allowance for credit losses calculation include pass, other assets especially mentioned (“OAEM”), substandard and doubtful. Additional information related to these credit quality categories is provided in Note 9, "Loans and Allowance for Credit Losses." Under this incurred methodology, the allowance calculation uses net historical charge-off trends to estimate probable unconfirmed losses for each loan category. A multiplier known as the emergence factor is applied to the historical loss rates for non-criticized loans. The emergence factor is calculated by loan category and represents the average time period from when a loss is incurred until the bank experiences a charge-off against the loan. Before applying the adjusted historical loss experience percentages, loan balances are reduced by the portion of the loan balances which are subject to guarantee by a government agency. Under the incurred model, loans acquired with evidence of credit deterioration were evaluated and not considered to be significant. The premium or discount estimated through the loan fair value calculation is recognized in interest income on a level yield or straight-line basis over the remaining contractual life of the loans. Additional credit deterioration on acquired loans, in excess of the original credit discount embedded in the fair value determination on the date of acquisition, was recognized in the allowance for credit losses through the provision for loan losses. As part of both CECL and the incurred methodology, all nonperforming credits, which includes nonaccrual loans and all troubled debt restructurings ("TDRs"), in excess of $250 thousand are individually evaluated on a quarterly basis. A specific reserve is established for individually evaluated loans in an amount equal to the total amount of estimated losses for the loans that are reviewed. Based on this reserve as a percentage of reviewed loan balances, a reserve is also established for the nonperforming loan balances that are not individually reviewed. An additional component of the allowance is determined by management based on a qualitative analysis of certain factors related to portfolio risks that are not incorporated in the calculated model. Factors considered by management include lending practices, ability and experience of the credit staff, the overall lending environment and external factors such as the regulatory environment and competition. Portfolio risks include unusual changes or recent trends in specific portfolios such as unexpected changes in the trends or levels of delinquency. No matter how detailed an analysis of potential credit losses is performed, these estimates are inherently imprecise. Management must make estimates using assumptions and information that is often subjective and changes rapidly.
Allowance for Off-Balance Sheet Credit Exposures	Allowance for Off-Balance Sheet Credit ExposuresFirst Commonwealth maintains an allowance for off-balance sheet credit exposure at a level deemed sufficient to absorb losses that are inherent to off-balance sheet credit risk. Off-balance sheet credit exposure includes commitments to extend credit, standby letters of credit and commercial letters of credit. The Company’s methodology for assessing the appropriateness of the allowance for off-balance sheet credit exposure consists of analysis of historical usage trends. The calculation begins with historical usage trends related to lines of credit as well as letters of credit and then utilizes those figures to determine the probable usage of available lines. These values are then adjusted by the expected loss percentage calculated for comparable loan categories as part of the allowance for credit losses for loans. This amount is adjusted quarterly and any change to the allowance is reported as part of provision expense on the Consolidated Statements of Income. The allowance for off-balance sheet credit exposures is reflected in "Other Liabilities" in the Consolidated Statements of Finance Condition.
Bank Owned Life Insurance	Bank Owned Life InsuranceFirst Commonwealth and the banks that First Commonwealth has acquired have purchased insurance on the lives of certain groups of employees. The policies accumulate asset values to meet future liabilities, including the payment of employee benefits such as health care. Increases in the cash surrender value are recorded as non-interest income in the Consolidated Statements of Income and cash receipts and disbursements are included in "Operating Activities" in the Consolidated Statements of Cash Flows. Under some of these policies, the beneficiaries receive a portion of the death benefit.
Premises and Equipment	Premises, Equipment and Lease Commitments Premises and equipment are carried at cost less accumulated depreciation on First Commonwealth’s Consolidated Statements of Financial Condition. Depreciation is computed on the straight-line and accelerated methods over the estimated useful life of the asset. A straight-line depreciation method was used for substantially all furniture and equipment. The straight-line depreciation method was used for buildings and improvements. Charges for maintenance and repairs are expensed as incurred. Leasehold improvements are expensed over the term of the lease or the estimated useful life of the improvement, whichever is shorter.
Goodwill	Goodwill Intangible assets resulting from acquisitions under the purchase method of accounting consist of goodwill and other intangible assets (see “Other Intangible Assets” section below). Goodwill is not amortized and is subject to at least annual assessments for impairment. First Commonwealth reviews goodwill annually and again at any quarter-end if a material event occurs during the quarter that may affect goodwill. When circumstances indicate that it is more likely than not that fair value is less than carrying value, a triggering event has occurred and a quantitative impairment test is performed. Goodwill is evaluated for potential impairment by determining if our fair value has fallen below carrying value.
Other Intangible Assets	Other Intangible Assets Other intangible assets consist of core deposits and customer lists obtained through acquisitions. Core deposit intangibles are amortized over their estimated lives using the present value of the benefit of the core deposits and straight-line methods of amortization. Customer list intangibles are amortized over the expected lives using expected cash flows based on retention of the customer base. These intangibles are evaluated for impairment on an annual basis and when events or changes in circumstances indicate that the carrying amount may not be recoverable.
Accounting for the Impairment of Long-Lived Assets	Accounting for the Impairment of Long-Lived Assets First Commonwealth reviews long-lived assets, such as premises and equipment and intangibles, for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. These changes in circumstances may include a significant decrease in the market value of an asset or the extent or manner in which an asset is used. If there is an indication that the carrying amount of an asset may not be recoverable, future undiscounted cash flows expected to result from the use of the asset are estimated. If the sum of the expected cash flows is less than the carrying value of the asset, a loss is recognized for the difference between the carrying value and fair value of the asset. Long-lived assets classified as held for sale are measured at the lower of their carrying amount or fair value less cost to sell. Depreciation or amortization is discontinued on long-lived assets classified as held for sale.
Income Taxes	Income TaxesFirst Commonwealth records taxes in accordance with the asset and liability method of FASB ASC Topic 740, “Income Taxes,” whereby deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amount of existing assets and liabilities and their respective tax bases given the provisions of the enacted tax laws. Deferred tax assets are reduced, if necessary, by the amount of such benefits that are more likely than not expected to be realized based upon available evidence. In accordance with FASB ASC Topic 740, interest or penalties incurred for taxes will be recorded as a component of noninterest expense.
Comprehensive Income Disclosures	Comprehensive Income Disclosures“Other Comprehensive Income” (comprehensive income, excluding net income) includes the after-tax effect of changes in unrealized holding gains and losses on available-for-sale securities, changes in the funded status of defined benefit postretirement plans and changes in the fair value of cash flow hedges. Comprehensive income is reported in the accompanying Consolidated Statements of Comprehensive Income, net of tax.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, federal funds sold and interest-bearing bank deposits. Generally, federal funds are sold for one-day periods.
Derivatives and Hedging Activities	Derivatives and Hedging Activities First Commonwealth accounts for derivative instruments and hedging activities in accordance with FASB ASC Topic 815, “Derivatives and Hedging.” All derivatives are evaluated at inception as to whether or not they are hedging or non-hedging activities, and appropriate documentation is maintained to support the final determination. First Commonwealth recognizes all derivatives as either assets or liabilities on the Consolidated Statements of Financial Condition and measures those instruments at fair value. For derivatives designated as fair value hedges, changes in the fair value of the derivative and the hedged item related to the hedged risk are recognized in earnings. Any hedge ineffectiveness would be recognized in the income statement line item pertaining to the hedged item. For derivatives designated as cash flow hedges, changes in fair value of the effective portion of the cash flow hedges are reported in other comprehensive income ("OCI"). When the cash flows associated with the hedged item are realized, the gain or loss included in OCI is recognized in the Consolidated Statement of Income. When First Commonwealth purchases a portion of a commercial loan that has an existing interest rate swap, it enters a Risk Participation Agreement with the counterparty and assumes the credit risk of the loan customer related to the swap. Any fee paid to First Commonwealth as a result of the risk participation agreement is offset by credit risk of the counterparties and is recognized in the income statement. Credit risk on the risk participation agreements is determined after considering the risk rating, probability of default and loss given default of the counterparties. Management periodically reviews contracts from various functional areas of First Commonwealth to identify potential derivatives embedded within selected contracts. As of December 31, 2020, First Commonwealth has interest rate derivative positions that are designated as hedging instruments and others that are not designated as hedging instruments. See Note 7, “Derivatives,” for a description of these instruments.
Earnings Per Common Share	Earnings Per Common Share Basic earnings per share excludes dilution and is computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted earnings per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in the earnings of
Fair Value Measurements	Fair Value Measurements In accordance with FASB ASC Topic 820, “Fair Value Measurements and Disclosures,” First Commonwealth groups financial assets and financial liabilities measured at fair value into three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are: • Level 1—Valuations for assets and liabilities traded in active exchange markets, such as the New York Stock Exchange. Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities. • Level 2—Valuations for assets and liabilities traded in less active dealer or broker markets. Valuations are obtained for identical or comparable assets or liabilities from alternative pricing sources with reasonable levels of price transparency. Level 2 securities include U.S. Government securities issued by Agencies and Sponsored Enterprises, Obligations of States and Political Subdivisions, certain corporate securities, FHLB stock, loans held for sale, interest rate derivatives that include interest rate swaps, risk participation agreements and foreign currency contracts, certain other real estate owned and certain nonperforming loans. • Level 3—Valuations for assets and liabilities that are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. If the inputs used to provide the evaluation are unobservable and/or there is very little, if any, market activity for the security or similar securities, the securities would be considered Level 3 securities. Level 3 valuations incorporate certain assumptions and projections in determining the fair value assigned to such assets or liabilities. The assets included in Level 3 are nonmarketable equity investments, certain other real estate owned and certain nonperforming loans. In general, fair values of financial instruments are based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon pricing models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality and our creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. See Note 17 “Fair Values of Assets and Liabilities” for additional information.
Revenue from Contract with Customer [Policy Text Block]	Revenue from Contracts with Customers First Commonwealth records revenue from contracts with customers in accordance with ASC Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. A significant component of the Company's revenue, net interest earned on financial assets and liabilities, is excluded from the scope of Topic 606. First Commonwealth generally fully satisfies its performance obligations on its contracts with customers as services are rendered and the transaction prices are typically fixed; charged either on a periodic basis or based on activity. Because performance obligations are satisfied as services are rendered and the transaction prices are fixed, the Company has made no significant judgments in applying the revenue guidance prescribed in Topic 606 that affect the determination of the amount and timing of revenue from contracts with customers.

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Summary of Net Assets Acquired and Consideration Transferred	The table below summarizes the final purchase price allocation and the net assets acquired (at fair value) and consideration received in connection with the Santander acquisition (dollars in thousands): Consideration Received Cash received $ 329,533 Fair Value of Assets Acquired Cash and cash equivalents 2,935 Loans 99,956 Premises and other equipment 3,637 Core deposit intangible 5,615 Other assets 770 Total assets acquired 112,913 Fair Value of Liabilities Assumed Deposits 471,386 Other liabilities 186 Total liabilities assumed 471,572 Total Fair Value of Identifiable Net Assets (358,659) Goodwill $ 29,126

Supplemental Comprehensive In_2

Supplemental Comprehensive Income Disclosures (Tables)	12 Months Ended
	Dec. 31, 2020
Supplemental Comprehensive Income Disclosures [Abstract]
Schedule of Amounts Recognized in Accumulated Other Comprehensive Income	The following table identifies the related tax effects allocated to each component of other comprehensive income in the Consolidated Statements of Comprehensive Income as of December 31. Reclassification adjustments related to securities available for sale are included in the “ Net securities gains ” line in the Consolidated Statements of Income and reclassification adjustments related to losses on derivatives are included in the "Other operating expenses" line in the Consolidated Statements of Income. 2020 2019 2018 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains (losses) on securities: Unrealized holding gains on securities arising during the period $ 19,981 $ (4,196) $ 15,785 $ 20,625 $ (4,331) $ 16,294 $ 2,783 $ (585) $ 2,198 Reclassification adjustment for gains on securities included in net income (70) 15 (55) (22) 5 (17) (8,102) 1,701 (6,401) Total unrealized gains (losses) on securities 19,911 (4,181) 15,730 20,603 (4,326) 16,277 (5,319) 1,116 (4,203) Unrealized gains (losses) on derivatives: Unrealized holding (losses) gains on derivatives arising during the period (4,467) 938 (3,529) 935 (196) 739 326 (68) 258 Reclassification adjustment for losses on derivatives included in net income — — — — — — 10 (3) 7 Total unrealized (losses) gains on derivatives (4,467) 938 (3,529) 935 (196) 739 336 (71) 265 Unrealized (losses) gains for postretirement obligations: Prior service cost (537) 113 (424) — — — — — — Net (loss) gain (155) 32 (123) (121) 25 (96) 144 (30) 114 Total unrealized (losses) gains for postretirement obligations (692) 145 (547) (121) 25 (96) 144 (30) 114 Total other comprehensive income (loss) $ 14,752 $ (3,098) $ 11,654 $ 21,417 $ (4,497) $ 16,920 $ (4,839) $ 1,015 $ (3,824) The following table sets forth the amounts recognized in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit costs as of December 31: 2020 2019 2018 (dollars in thousands) Amounts recognized in accumulated other comprehensive income, net of tax: Net (gain) loss $ (243) $ (366) $ (461) Prior service cost 424 — — Total $ 181 $ (366) $ (461)
Related Tax Effects Allocated to Each Component of Other Comprehensive Income	The following table details the change in components of OCI for the year-ended December 31: 2020 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at December 31 $ 4,580 $ 634 $ 365 $ 5,579 Other comprehensive income before reclassification adjustment 15,785 (3,529) 12,256 Amounts reclassified from accumulated other comprehensive income (loss) (55) — (55) Prior service cost (424) (424) Net gain (123) (123) Net other comprehensive income during the period 15,730 (3,529) (547) 11,654 Balance at December 31 $ 20,310 $ (2,895) $ (182) $ 17,233 2019 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (11,697) $ (105) $ 461 $ (11,341) Other comprehensive income before reclassification adjustment 16,294 739 17,033 Amounts reclassified from accumulated other comprehensive income (loss) (17) — (17) Net gain (96) (96) Net other comprehensive income during the period 16,277 739 (96) 16,920 Balance at December 31 $ 4,580 $ 634 $ 365 $ 5,579 2018 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (6,166) $ (306) $ 299 $ (6,173) Cumulative effect of adoption of ASU 2018-02 (1,328) (64) 48 (1,344) Balance at January 1 (7,494) (370) 347 (7,517) Other comprehensive income before reclassification adjustment 2,198 258 2,456 Amounts reclassified from accumulated other comprehensive income (loss) (6,401) 7 (6,394) Net gain 114 114 Net other comprehensive income during the period (4,203) 265 114 (3,824) Balance at December 31 $ (11,697) $ (105) $ 461 $ (11,341)

Supplemental Cash Flow Disclo_2

Supplemental Cash Flow Disclosures (Tables)	12 Months Ended
	Dec. 31, 2020
Supplemental Cash Flow Information [Abstract]
Non-cash Investing and Financing Activities	The following table presents information related to cash paid during the year for interest and income taxes as well as detail on non-cash investing and financing activities for the years ended December 31: 2020 2019 2018 (dollars in thousands) Cash paid during the period for: Interest $ 33,964 $ 56,005 $ 40,071 Income taxes 25,914 21,787 23,826 Non-cash investing and financing activities: Loans transferred to other real estate owned and repossessed assets 3,865 4,723 4,334 Fair value of loans transferred from held to maturity to available for sale 37,305 30,359 37,367 Loans transferred from available for sale to held to maturity 4,335 482 — Gross increase (decrease) in market value adjustment to securities available for sale 19,911 20,604 (5,319) Gross (decrease) increase in market value adjustment to derivatives (4,467) 935 336 Investments committed to purchase, not settled (34,185) 25,484 — Increase in limited partnership investment unfunded commitment — 1,469 — Net assets (liabilities) acquired through acquisition — (361,595) 21,834 Proceeds from death benefit on bank-owned life insurance not received (384) 484 — Treasury shares issued 1,594 2,531 2,257

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Composition of Weighted-Average Common Shares (Denominator) Used in Basic and Diluted Earnings Per Share	The following table summarizes the composition of the weighted-average common shares (denominator) used in the basic and diluted earnings per share computation for the years ending December 31: 2020 2019 2018 Weighted average common shares issued 113,914,902 113,914,902 113,914,902 Average treasury shares (16,254,304) (15,447,299) (14,747,687) Average deferred compensation shares (42,751) (37,496) (37,411) Average unearned nonvested shares (118,261) (112,320) (93,641) Weighted average common shares and common stock equivalents used to calculate basic earnings per share 97,499,586 98,317,787 99,036,163 Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share 203,836 231,957 149,939 Additional common stock equivalents (deferred compensation) used to calculated diluted earnings per share 55,543 38,420 37,411 Weighted average common shares and common stock equivalents used to calculate diluted earnings per share 97,758,965 98,588,164 99,223,513 Per Share Data Basic Earnings Per Share $ 0.75 $ 1.07 $ 1.09 Diluted Earnings Per Share $ 0.75 $ 1.07 $ 1.08
Common Stock Equivalents Not Included in Computation of Diluted Earnings Per Share	The following table shows the number of shares and the price per share related to common stock equivalents that were not included in the computation of diluted earnings per share for the years ended December 31, because to do so would have been anti-dilutive. 12/31/2020 12/31/2019 12/31/2018 Price Range Price Range Price Range Shares From To Shares From To Shares From To Restricted Stock 92,499 $ 13.72 $ 15.44 81,730 $ 12.99 $ 15.44 71,560 $ 8.84 $ 14.49 Restricted Stock Units 106,931 $ 12.43 $ 15.37 26,217 $ 16.62 $ 16.62 — $ — $ —

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Credit Value Adjustment Recorded Related to Notional Amount of Derivatives Outstanding	The following table depicts the credit value adjustment recorded relative to the notional amount of derivatives outstanding as well as the notional amount of risk participation agreements participated to other banks at December 31: 2020 2019 (dollars in thousands) Derivatives not Designated as Hedging Instruments Credit value adjustment $ (2,792) $ (272) Notional Amount: Interest rate derivatives 631,446 587,275 Interest rate caps 66,527 87,188 Interest rate collars 35,354 35,354 Risk participation agreements 220,280 164,632 Sold credit protection on risk participation agreements (78,522) (69,011) Interest rate options 47,874 25,460 Derivatives Designated as Hedging Instruments Interest rate swaps: Fair value adjustment (3,665) 801 Notional Amount 70,000 70,000 Interest rate forwards: Fair value adjustment (483) (63) Notional Amount 65,000 30,000 Foreign exchange forwards: Fair value adjustment (5) (41) Notional Amount 2,119 4,789
Schedule of Change in Fair Value of Derivative Assets and Liabilities	The table below presents the amount representing the change in the fair value of derivative assets and derivative liabilities attributable to credit risk included in “Other income” on the Consolidated Statements of Income for the years ended December 31: 2020 2019 2018 (dollars in thousands) Non-hedging interest rate derivatives: (Decrease) increase in other income $ (981) $ (269) $ 787 Decrease in other expense — (352) (332) Hedging interest rate derivatives: Decrease in interest and fees on loans — (118) (590) Increase (decrease) in interest from subordinated debentures 449 (159) — Increase in other expense — 7 10 Hedging interest rate forwards: Increase in other income 420 106 — Decrease in other expense — — (189) Hedging interest rate derivatives: Increase in other expense 18 5 15

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Cumulative Roll Forward of Credit Losses Recognized in Earnings for Debt Securities Held and Not Intended to be Sold	There was no expected credit related impairment recognized on investment securities during the twelve months ended December 31, 2020. Prior to 2020, investment securities were evaluated for other-than-temporary impairment. During 2018, all of our pooled trust preferred collateralized debt obligations were liquidated either through a successful auction call or sale. Other-than-temporary impairment charges were recognized on the pooled trust preferred securities in 2008, 2009 and 2010. The following table provides a cumulative roll forward of credit losses recognized in earnings for the trust preferred securities for the years ended December 31: 2019 2018 (dollars in thousands) Balance, beginning (a) $ — $ 12,208 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — Increases in cash flows expected to be collected, recognized over the remaining life of the securities (b) — (223) Reduction for debt securities sold during the period — (9,164) Reduction for debt securities called during the period — (2,821) Balance, ending $ — $ — (a) The beginning balance represents credit related losses included in other-than-temporary impairment charges recognized on debt securities in prior periods. (b) Represents the increase in cash flows recognized either as principal payments or interest income during the period.
Held-to-maturity Securities	Below is an analysis of the amortized cost and fair values of debt securities held to maturity at December 31: 2020 2019 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 2,766 $ 138 $ — $ 2,904 $ 3,392 $ 57 $ — $ 3,449 Mortgage-Backed Securities – Commercial 36,799 1,441 — 38,240 51,291 18 (184) 51,125 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 277,351 5,389 (10) 282,730 229,667 1,377 (294) 230,750 Mortgage-Backed Securities – Commercial 9,737 344 — 10,081 12,081 67 — 12,148 Obligations of States and Political Subdivisions 34,391 705 — 35,096 40,092 554 — 40,646 Debt Securities Issued by Foreign Governments 800 — — 800 600 — — 600 Total Securities Held to Maturity $ 361,844 $ 8,017 $ (10) $ 369,851 $ 337,123 $ 2,073 $ (478) $ 338,718
Analysis of Amortized Cost and Estimated Fair Values of Securities Available for Sale	Below is an analysis of the amortized cost and fair values of securities available for sale at December 31: 2020 2019 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 6,492 $ 738 $ — $ 7,230 $ 7,745 $ 596 $ — $ 8,341 Mortgage-Backed Securities – Commercial 182,823 8,357 — 191,180 186,316 2,983 (166) 189,133 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 481,109 14,924 — 496,033 660,777 4,113 (2,943) 661,947 Other Government-Sponsored Enterprises 100,996 2 — 100,998 1,000 — — 1,000 Obligations of States and Political Subdivisions 11,154 243 — 11,397 17,738 171 — 17,909 Corporate Securities 22,941 1,444 — 24,385 22,919 1,043 — 23,962 Total Securities Available for Sale $ 805,515 $ 25,708 $ — $ 831,223 $ 896,495 $ 8,906 $ (3,109) $ 902,292 The amortized cost and estimated fair value of debt securities available for sale at December 31, 2020, by contractual maturity, are shown below: Amortized Estimated (dollars in thousands) Due within 1 year $ 104,995 $ 105,015 Due after 1 but within 5 years 19,349 20,395 Due after 5 but within 10 years 10,747 11,370 Due after 10 years — — 135,091 136,780 Mortgage-Backed Securities (a) 670,424 694,443 Total Debt Securities $ 805,515 $ 831,223 (a) Mortgage Backed Securities include an amortized cost of $189.3 million and a fair value of $198.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $481.1 million and a fair value of $496.0 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.
Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale	Mortgage Backed Securities include an amortized cost of $189.3 million and a fair value of $198.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $481.1 million and a fair value of $496.0 million
Investments Classified by Contractual Maturity Date	The amortized cost and estimated fair value of debt securities held to maturity at December 31, 2020, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Amortized Estimated (dollars in thousands) Due within 1 year $ 2,500 $ 2,525 Due after 1 but within 5 years 7,669 7,742 Due after 5 but within 10 years 20,126 20,689 Due after 10 years 4,896 4,940 35,191 35,896 Mortgage-Backed Securities (a) 326,653 333,955 Total Debt Securities $ 361,844 $ 369,851 (a) Mortgage Backed Securities include an amortized cost of $39.6 million and a fair value of $41.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $287.1 million and a fair value of $292.8 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The following table presents the gross unrealized losses and estimated fair values at December 31, 2020 for available for sale securities for which an allowance for credit losses has not been recorded and held to maturity securities by investment category and time frame for which the securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 3,755 (10) — — 3,755 (10) Total Securities $ 3,755 $ (10) $ — $ — $ 3,755 $ (10)	The following table presents the gross unrealized losses and estimated fair value at December 31, 2019 for both available for sale and held to maturity securities by investment category and time frame for which the securities had been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Commercial $ 54,501 $ (201) $ 16,365 $ (149) $ 70,866 $ (350) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 111,969 (436) 219,015 (2,801) 330,984 (3,237) Total Securities $ 166,470 $ (637) $ 235,380 $ (2,950) $ 401,850 $ (3,587)

Loans and Allowance for Credi_2

Loans and Allowance for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Abstract]
Outstanding Balances of Loan	The following table provides outstanding balances related to each of our loan types as of December 31: 2020 2019 Total Loans Originated Loans Acquired Loans Total Loans (dollars in thousands) Commercial, financial, agricultural and other $ 1,555,986 $ 1,212,026 $ 29,827 $ 1,241,853 Time and demand 1,541,382 Commercial credit cards 14,604 Real estate construction 427,221 442,777 6,262 449,039 Residential real estate 1,750,592 1,415,808 265,554 1,681,362 Residential first lien 1,144,323 Residential junior lien/home equity 606,269 Commercial real estate 2,211,569 1,958,346 159,173 2,117,519 Multifamily 371,239 Nonowner occupied 1,421,151 Owner occupied 419,179 Loans to individuals 815,815 685,416 13,959 699,375 Automobile 712,800 Consumer credit cards 12,360 Consumer other 90,655 Total loans $ 6,761,183 $ 5,714,373 $ 474,775 $ 6,189,148
Credit Risk Profile by Creditworthiness	The following tables represent our credit risk profile by creditworthiness category for the years ended December 31: 2020 Non-Pass Pass OAEM Substandard Doubtful Loss Total Non-Pass Total (dollars in thousands) Commercial, financial, agricultural and other $ 1,491,916 $ 48,233 $ 15,837 $ — $ — $ 64,070 $ 1,555,986 Time and demand 1,477,312 48,233 15,837 — — 64,070 1,541,382 Commercial credit cards 14,604 — — — — — 14,604 Real estate construction 426,663 504 54 — — 558 427,221 Residential real estate 1,740,992 1,902 7,698 — — 9,600 1,750,592 Residential first lien 1,138,409 1,780 4,134 — — 5,914 1,144,323 Residential junior lien/home equity 602,583 122 3,564 — — 3,686 606,269 Commercial real estate 1,983,258 175,995 52,316 — — 228,311 2,211,569 Multifamily 369,883 131 1,225 — — 1,356 371,239 Nonowner occupied 1,216,252 161,336 43,563 — — 204,899 1,421,151 Owner occupied 397,123 14,528 7,528 — — 22,056 419,179 Loans to individuals 815,541 — 274 — — 274 815,815 Automobile 712,539 — 261 — — 261 712,800 Consumer credit cards 12,360 — — — — — 12,360 Consumer other 90,642 — 13 — — 13 90,655 Total $ 6,458,370 $ 226,634 $ 76,179 $ — $ — $ 302,813 $ 6,761,183 2019 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Originated Loans Pass $ 1,171,363 $ 442,751 $ 1,406,845 $ 1,918,690 $ 685,108 $ 5,624,757 Non-Pass OAEM 29,359 26 475 13,533 — 43,393 Substandard 11,304 — 8,488 26,123 308 46,223 Doubtful — — — — — — Total Non-Pass 40,663 26 8,963 39,656 308 89,616 Total $ 1,212,026 $ 442,777 $ 1,415,808 $ 1,958,346 $ 685,416 $ 5,714,373 Acquired Loans Pass $ 27,696 $ 5,697 $ 262,630 $ 153,814 $ 13,947 $ 463,784 Non-Pass OAEM 2,009 565 537 2,072 — 5,183 Substandard 122 — 2,387 3,287 12 5,808 Doubtful — — — — — — Total Non-Pass 2,131 565 2,924 5,359 12 10,991 Total $ 29,827 $ 6,262 $ 265,554 $ 159,173 $ 13,959 $ 474,775 The following table summarizes the loan risk rating category by loan type including term loans on an amortized cost basis by origination year as of December 31, 2020: Term Loans Revolving Loans 2020 2019 2018 2017 2016 Prior Total (dollars in thousands) Time and demand $ 598,053 $ 193,601 $ 142,224 $ 72,277 $ 74,228 $ 83,313 $ 377,686 $ 1,541,382 Pass 597,405 189,834 140,473 63,137 68,007 65,418 353,038 1,477,312 OAEM 93 3,373 972 8,820 6,182 8,043 20,750 48,233 Substandard 555 394 779 320 39 9,852 3,898 15,837 Commercial credit cards — — — — — — 14,604 14,604 Pass — — — — — — 14,604 14,604 Real estate construction 150,493 133,195 104,167 34,803 389 1,009 3,165 427,221 Pass 150,493 133,195 104,167 34,803 389 709 2,907 426,663 OAEM — — — — — 246 258 504 Substandard — — — — — 54 — 54 Residential first lien 316,052 184,550 142,823 110,365 91,495 297,057 1,981 1,144,323 Pass 316,028 184,533 142,467 110,260 91,059 292,158 1,904 1,138,409 OAEM — — 83 — 100 1,520 77 1,780 Substandard 24 17 273 105 336 3,379 — 4,134 Residential junior lien/home equity 3,055 5,783 4,545 2,005 1,303 7,127 582,451 606,269 Pass 3,055 5,698 4,545 2,005 1,303 6,909 579,068 602,583 OAEM — — — — — 112 10 122 Substandard — 85 — — — 106 3,373 3,564 Multifamily 76,249 16,287 69,439 66,963 34,383 106,328 1,590 371,239 Pass 76,249 16,287 69,439 66,963 34,383 104,972 1,590 369,883 OAEM — — — — — 131 — 131 Substandard — — — — — 1,225 — 1,225 Nonowner occupied 105,861 199,280 161,018 214,915 217,883 518,052 4,142 1,421,151 Pass 105,861 190,301 139,643 181,659 175,148 419,900 3,740 1,216,252 OAEM — 8,979 21,375 26,339 37,762 66,752 129 161,336 Substandard — — — 6,917 4,973 31,400 273 43,563 Owner occupied 59,519 72,313 61,079 40,796 27,415 152,555 5,502 419,179 Pass 58,551 70,726 55,478 39,351 26,359 141,376 5,282 397,123 OAEM 968 684 4,736 1,421 114 6,572 33 14,528 Substandard — 903 865 24 942 4,607 187 7,528 Automobile 350,293 202,923 96,355 45,218 14,285 3,726 — 712,800 Pass 350,293 202,827 96,336 45,187 14,255 3,641 — 712,539 Substandard — 96 19 31 30 85 — 261 Consumer credit cards — — — — — — 12,360 12,360 Pass — — — — — — 12,360 12,360 Consumer other 7,814 14,464 10,752 1,965 711 6,383 48,566 90,655 Pass 7,814 14,464 10,752 1,965 711 6,373 48,563 90,642 Substandard — — — — — 10 3 13 Total $ 1,667,389 $ 1,022,396 $ 792,402 $ 589,307 $ 462,092 $ 1,175,550 $ 1,052,047 $ 6,761,183
Age Analysis of Past Due Loans by Segment	The following tables delineate the aging analysis of the recorded investments in past due loans as of December 31. Also included in these tables are loans that are 90 days or more past due and still accruing because they are well-secured and in the process of collection. 2020 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 146 $ 62 $ 112 $ 3,317 $ 3,637 $ 1,552,349 $ 1,555,986 Time and demand 97 28 23 3,317 3,465 1,537,917 1,541,382 Commercial credit cards 49 34 89 — 172 14,432 14,604 Real estate construction 936 — — 54 990 426,231 427,221 Residential real estate 3,883 1,492 769 6,824 12,968 1,737,624 1,750,592 Residential first lien 1,775 660 267 3,489 6,191 1,138,132 1,144,323 Residential junior lien/home equity 2,108 832 502 3,335 6,777 599,492 606,269 Commercial real estate 237 160 3 35,072 35,472 2,176,097 2,211,569 Multifamily — — — 460 460 370,779 371,239 Nonowner occupied 18 104 — 31,822 31,944 1,389,207 1,421,151 Owner occupied 219 56 3 2,790 3,068 416,111 419,179 Loans to individuals 2,870 852 639 274 4,635 811,180 815,815 Automobile 2,090 417 94 261 2,862 709,938 712,800 Consumer credit cards 52 39 123 — 214 12,146 12,360 Consumer other 728 396 422 13 1,559 89,096 90,655 Total $ 8,072 $ 2,566 $ 1,523 $ 45,541 $ 57,702 $ 6,703,481 $ 6,761,183 2019 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Originated Loans Commercial, financial, agricultural and other $ 391 $ 57 $ 140 $ 8,780 $ 9,368 $ 1,202,658 $ 1,212,026 Real estate construction 198 — 9 — 207 442,570 442,777 Residential real estate 3,757 749 736 6,646 11,888 1,403,920 1,415,808 Commercial real estate 227 114 — 6,609 6,950 1,951,396 1,958,346 Loans to individuals 4,070 1,020 931 307 6,328 679,088 685,416 Total $ 8,643 $ 1,940 $ 1,816 $ 22,342 $ 34,741 $ 5,679,632 $ 5,714,373 Acquired Loans Commercial, financial, agricultural and other $ 1 $ — $ 1 $ 74 $ 76 $ 29,751 $ 29,827 Real estate construction — — — — — 6,262 6,262 Residential real estate 304 207 221 1,949 2,681 262,873 265,554 Commercial real estate — 107 — 298 405 158,768 159,173 Loans to individuals 87 89 35 12 223 13,736 13,959 Total $ 392 $ 403 $ 257 $ 2,333 $ 3,385 $ 471,390 $ 474,775
Recorded Investment and Unpaid Principal Balance for Impaired Loans with Associated Allowance	The following tables include the recorded investment and unpaid principal balance for nonperforming loans with the associated allowance amount, if applicable, as of December 31, 2020 and 2019. Also presented are the average recorded investment in nonperforming loans and the related amount of interest recognized while the loan was considered nonperforming for the years ended December 31, 2020, 2019 and 2018. Average balances are calculated based on month-end balances of the loans for the period reported and are included in the table below based on its period end allowance position. 2020 Recorded Unpaid Related Average Interest (dollars in thousands) With no related specific allowance recorded: Commercial, financial, agricultural and other $ 2,025 $ 2,725 $ 6,371 $ 80 Time and demand 2,025 2,725 6,371 80 Real estate construction 54 53 146 14 Residential real estate 10,939 13,258 11,913 335 Residential first lien 6,062 7,575 6,605 241 Residential junior lien/home equity 4,877 5,683 5,308 94 Commercial real estate 20,650 23,641 22,287 184 Multifamily 1 82 1 — Nonowner occupied 16,786 19,459 18,536 82 Owner occupied 3,863 4,100 3,750 102 Loans to individuals 418 447 470 13 Automobile 405 430 447 13 Consumer other 13 17 23 — Subtotal 34,086 40,124 41,187 626 With a specific allowance recorded: Commercial, financial, agricultural and other 4,210 9,377 1,268 1,544 3 Time and demand 4,210 9,377 1,268 1,544 3 Real estate construction — — — — — Residential real estate — — — — — Residential first lien — — — — — Residential junior lien/home equity — — — — — Commercial real estate 15,757 15,830 3,638 7,997 10 Multifamily 459 470 116 395 — Nonowner occupied 15,060 15,122 3,508 7,363 — Owner occupied 238 238 14 239 10 Loans to individuals — — — — — Automobile — — — — — Consumer other — — — — — Subtotal 19,967 25,207 4,906 9,541 13 Total $ 54,053 $ 65,331 $ 4,906 $ 50,728 $ 639 2019 Recorded Unpaid Related Average Interest (dollars in thousands) Originated Loans: With no related specific allowance recorded: Commercial, financial, agricultural and other $ 1,848 $ 6,997 $ 2,411 $ 66 Real estate construction — — — — Residential real estate 10,372 12,437 10,819 365 Commercial real estate 3,015 3,210 7,455 156 Loans to individuals 406 640 371 17 Subtotal 15,641 23,284 21,056 604 With a specific allowance recorded: Commercial, financial, agricultural and other 8,290 10,032 $ 1,580 4,110 77 Real estate construction — — — — — Residential real estate 474 498 1 241 — Commercial real estate 5,293 5,308 851 1,747 3 Loans to individuals — — — — — Subtotal 14,057 15,838 2,432 6,098 80 Total $ 29,698 $ 39,122 $ 2,432 $ 27,154 $ 684 Acquired Loans: With no related specific allowance recorded: Commercial, financial, agricultural and other $ 73 $ 73 $ 2,479 $ — Real estate construction — — — — Residential real estate 2,136 2,585 1,986 8 Commercial real estate 298 320 747 18 Loans to individuals 12 15 13 — Subtotal 2,519 2,993 5,225 26 With a specific allowance recorded: Commercial, financial, agricultural and other — — $ — — — Real estate construction — — — — — Residential real estate — — — — — Commercial real estate — — — — — Loans to individuals — — — — — Subtotal — — — — — Total $ 2,519 $ 2,993 $ — $ 5,225 $ 26 2018 Originated Acquired Average Interest Average Interest (dollars in thousands) With no related specific allowance recorded: Commercial, financial, agricultural and other $ 18,480 $ 602 $ 214 $ 10 Real estate construction — — — — Residential real estate 10,651 271 1,906 5 Commercial real estate 7,919 177 1,565 — Loans to individuals 310 11 16 — Subtotal 37,360 1,061 3,701 15 With a specific allowance recorded: Commercial, financial, agricultural and other 2,531 20 11 — Real estate construction — — — — Residential real estate 504 13 — — Commercial real estate 991 4 — — Loans to individuals — — — — Subtotal 4,026 37 11 — Total $ 41,386 $ 1,098 $ 3,712 $ 15
Troubled Debt Restructured Loans and Commitments	The following table provides detail as to the total troubled debt restructured loans and total commitments outstanding on troubled debt restructured loans as of December 31: 2020 2019 2018 (dollars in thousands) Troubled debt restructured loans Accrual status $ 8,512 $ 7,542 $ 8,757 Nonaccrual status 14,740 6,037 11,761 Total $ 23,252 $ 13,579 $ 20,518 Commitments Letters of credit $ 60 $ 60 $ 60 Unused lines of credit 11 163 1,027 Total $ 71 $ 223 $ 1,087 2020 2019 2018 Number of Recorded Number of Recorded Number of Recorded (dollars in thousands) Residential real estate 1 $ 34 — $ — 1 $ 49 Residential junior lien/home equity 1 34 Loans to individuals 2 74 — — — — Automobile 2 74 Total 3 $ 108 — $ — 1 $ 49
Troubled Debt Restructurings is 90 Days or More Past Due	The following tables provide detail, including specific reserve and reasons for modification, related to loans identified as troubled debt restructurings during the years ending December 31: 2020 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 4 $ — $ 629 $ 2,176 $ 2,805 $ 2,196 $ 636 Time and demand 4 — 629 2,176 2,805 2,196 636 Residential real estate 18 — 33 917 950 791 — Residential first lien 9 — 33 513 546 411 — Residential junior lien/home equity 9 — — 404 404 380 — Commercial real estate 5 — — 10,857 10,857 10,758 — Nonowner occupied 4 — — 10,289 10,289 10,263 — Owner occupied 1 — — 568 568 495 — Loans to individuals 14 — 114 148 262 224 — Automobile 14 $ — $ 114 $ 148 262 $ 224 $ — Total 41 $ — $ 776 $ 14,098 $ 14,874 $ 13,969 $ 636 2019 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 2 $ — $ — $ 156 $ 156 $ 154 $ — Residential real estate 20 17 204 965 1,186 1,059 — Commercial real estate 5 — 556 6,261 6,817 594 — Loans to individuals 11 — — 143 143 121 — Total 38 $ 17 $ 760 $ 7,525 $ 8,302 $ 1,928 $ — 2018 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 3 $ 74 $ — $ 8,250 $ 8,324 $ 6,104 $ — Residential real estate 37 242 241 1,316 1,799 1,638 — Commercial real estate 3 — — 1,016 1,016 975 — Loans to individuals 15 — 89 53 142 112 — Total 58 $ 316 $ 330 $ 10,635 $ 11,281 $ 8,829 $ —
Allowance for Credit Losses	The following tables provide detail related to the allowance for credit losses for the years ended December 31. 2020 Beginning balance Impact of adoption of CECL Charge-offs Recoveries Provision (credit) a Ending balance (dollars in thousands) Commercial, financial, agricultural and other $ 20,234 $ 1,478 $ (6,318) $ 314 $ 1,479 $ 17,187 Time and demand — 21,242 (6,220) 301 1,515 16,838 Commercial credit cards — 470 (98) 13 (36) 349 Real estate construction 2,558 562 — 26 4,820 7,966 Residential real estate 4,093 7,276 (1,040) 414 3,615 14,358 Residential first liens — 7,326 (550) 296 847 7,919 Residential junior liens/home equity — 4,043 (490) 118 2,768 6,439 Commercial real estate 19,768 (207) (4,939) 312 27,019 41,953 Multifamily — 1,647 — — 4,593 6,240 Nownowner occupied — 12,317 (4,678) 187 20,588 28,414 Owner occupied — 5,597 (261) 125 1,838 7,299 Loans to individuals 4,984 4,284 (6,953) 991 16,539 19,845 Automobile — 6,106 (3,954) 745 13,236 16,133 Consumer credit cards — 221 (595) 36 973 635 Consumer other — 2,941 (2,404) 210 2,330 3,077 Total $ 51,637 $ 13,393 $ (19,250) $ 2,057 $ 53,472 $ 101,309 a) The provision (credit) shown here excludes the provision for off-balance sheet credit exposure included in the income statement. December 31, 2020 Loans Ending balance Ending balance: individually evaluated for credit losses Ending balance: collectively evaluated for credit losses Ending balance Ending balance: individually evaluated for credit losses Ending balance: collectively evaluated for credit losses (dollars in thousands) Commercial, financial, agricultural and other $ 17,187 $ 1,268 $ 15,919 $ 1,555,986 $ 5,411 $ 1,550,575 Time and demand 16,838 1,268 15,570 1,541,382 5,411 1,535,971 Commercial credit cards 349 — 349 14,604 — 14,604 Real estate construction 7,966 — 7,966 427,221 — 427,221 Residential real estate 14,358 — 14,358 1,750,592 1,105 1,749,487 Residential first liens 7,919 — 7,919 1,144,323 528 1,143,795 Residential junior liens/home equity 6,439 — 6,439 606,269 577 605,692 Commercial real estate 41,953 3,638 38,315 2,211,569 34,947 2,176,622 Multifamily 6,240 116 6,124 371,239 459 370,780 Nownowner occupied 28,414 3,508 24,906 1,421,151 31,450 1,389,701 Owner occupied 7,299 14 7,285 419,179 3,038 416,141 Loans to individuals 19,845 — 19,845 815,815 — 815,815 Automobile 16,133 — 16,133 712,800 — 712,800 Consumer credit cards 635 — 635 12,360 — 12,360 Consumer other 3,077 — 3,077 90,655 — 90,655 Total $ 101,309 $ 4,906 $ 96,403 $ 6,761,183 $ 41,463 $ 6,719,720 2019 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Originated Loans: Beginning balance $ 19,235 $ 2,002 $ 3,934 $ 18,382 $ 4,033 $ 47,586 Charge-offs (2,667) — (986) (632) (5,747) (10,032) Recoveries 245 158 246 189 611 1,449 Provision (credit) 3,408 398 897 1,792 6,087 12,582 Ending balance 20,221 2,558 4,091 19,731 4,984 51,585 Acquired Loans: Beginning balance $ 139 $ — $ 35 $ 4 $ — $ 178 Charge-offs (726) — (56) (1,376) (84) (2,242) Recoveries 81 — 69 — 15 165 Provision (credit) 519 — (46) 1,409 69 1,951 Ending balance 13 — 2 37 — 52 Total ending balance $ 20,234 $ 2,558 $ 4,093 $ 19,768 $ 4,984 $ 51,637 Ending balance: individually evaluated for impairment $ 1,580 $ — $ 1 $ 851 $ — $ 2,432 Ending balance: collectively evaluated for impairment 18,654 2,558 4,092 18,917 4,984 49,205 Loans: Ending balance 1,241,853 449,039 1,681,362 2,117,519 699,375 6,189,148 Ending balance: individually evaluated for impairment 9,246 — 1,741 6,846 — 17,833 Ending balance: collectively evaluated for impairment 1,232,607 449,039 1,679,621 2,110,673 699,375 6,171,315 2018 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Originated Loans: Beginning balance $ 23,418 $ 1,349 $ 2,753 $ 17,328 $ 3,404 $ 48,252 Charge-offs (5,201) — (1,217) (3,930) (4,554) (14,902) Recoveries 746 135 233 153 579 1,846 Provision (credit) 272 518 2,165 4,831 4,604 12,390 Ending balance 19,235 2,002 3,934 18,382 4,033 47,586 Acquired Loans: Beginning balance 11 — 6 29 — 46 Charge-offs (93) — (96) — (22) (211) Recoveries 42 6 128 — 26 202 Provision (credit) 179 (6) (3) (25) (4) 141 Ending balance 139 — 35 4 — 178 Total ending balance $ 19,374 $ 2,002 $ 3,969 $ 18,386 $ 4,033 $ 47,764 Ending balance: individually evaluated for impairment $ 928 $ — $ 107 $ 596 $ — $ 1,631 Ending balance: collectively evaluated for impairment 18,446 2,002 3,862 17,790 4,033 46,133 Loans: Ending balance 1,138,473 358,978 1,562,405 2,123,544 590,739 5,774,139 Ending balance: individually evaluated for impairment 11,631 — 3,747 5,710 — 21,088 Ending balance: collectively evaluated for impairment 1,126,842 358,978 1,558,658 2,117,834 590,739 5,753,051

Commitments and Letters of Cr_2

Commitments and Letters of Credit (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Notional Amount of Commitments and Letter of Credit Instruments	The following table identifies the notional amount of those instruments at December 31: 2020 2019 (dollars in thousands) Financial instruments whose contract amounts represent credit risk: Commitments to extend credit $ 2,097,628 $ 1,981,275 Financial standby letters of credit 15,988 16,630 Performance standby letters of credit 16,864 23,293 Commercial letters of credit 783 783

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Premises and Equipment	Premises and equipment are described as follows: Estimated Useful Life 2020 2019 (dollars in thousands) Land Indefinite $ 15,441 $ 15,446 Buildings and improvements 10-50 years 77,003 76,965 Operating lease right of use asset 1-25 years 48,642 52,114 Leasehold improvements 5-40 years 35,347 37,716 Furniture and equipment 3-7 years 73,150 71,548 Software 3-7 years 41,681 40,399 Subtotal 291,264 294,188 Less accumulated depreciation and amortization 165,747 156,920 Total premises and equipment, net $ 125,517 $ 137,268
Lessee, Operating Lease, Disclosure [Table Text Block]	The following table represents the lease costs and other lease information for the years ended December 31. 2020 2019 (dollars in thousands) Balance sheet: Operating lease asset classified as premises and equipment $ 42,617 $ 48,642 Operating lease liability classified as other liabilities 46,819 52,894 Income statement: Operating lease cost classified as occupancy and equipment expense $ 5,930 $ 5,328 Weighted average lease term, in years 14.83 15.27 Weighted average discount rate 3.42 % 3.43 % Operating cash flows $ 5,979 $ 4,656
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The following table reconciles future minimum lease payments due under non-cancelable operating leases (those amounts subject to recognition) to the lease liability a s of December 31, 2020 (dollars in thousands): For the twelve months ended 2021 $ 4,765 2022 4,653 2023 4,533 2024 4,399 2025 4,174 Thereafter 38,325 Total future minimum lease payments 60,849 Less remaining imputed interest 14,030 Operating lease liability $ 46,819

Goodwill and Other Amortizing_2

Goodwill and Other Amortizing Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill Disclosure [Abstract]
Summarized Other Intangible Assets	The following table summarizes other intangible assets: Gross Accumulated Net (dollars in thousands) December 31, 2020 Customer deposit intangibles $ 22,573 $ (11,653) $ 10,920 Customer list intangible 2,283 (1,570) 713 Total other intangible assets $ 24,856 $ (13,223) $ 11,633 December 31, 2019 Customer deposit intangibles $ 25,843 $ (11,760) $ 14,083 Customer list intangible 2,283 (1,340) 943 Total other intangible assets $ 28,126 $ (13,100) $ 15,026
Estimated Amortization Expense of Core Deposit Intangibles	The following presents the estimated amortization expense of core deposit and customer list intangibles: Core Deposit Intangibles Customer List Intangible Total (dollars in thousands) 2021 $ 2,753 $ 193 $ 2,946 2022 2,343 159 2,502 2023 1,933 127 2,060 2024 1,522 97 1,619 2025 1,112 69 1,181 Thereafter 1,257 68 1,325 Total $ 10,920 $ 713 $ 11,633

Interest-Bearing Deposits (Tabl

Interest-Bearing Deposits (Tables)	12 Months Ended
	Dec. 31, 2020
Deposits [Abstract]
Components of Interest-Bearing Deposits	Components of interest-bearing deposits at December 31 were as follows: 2020 2019 (dollars in thousands) Interest-bearing demand deposits $ 250,353 $ 254,981 Savings deposits 4,305,391 3,896,536 Time deposits 562,964 835,851 Total interest-bearing deposits $ 5,118,708 $ 4,987,368
Scheduled Maturities of Time Deposits	Included in time deposits at December 31, 2020, were certificates of deposit with the following scheduled maturities (dollars in thousands): 2021 $ 419,197 2022 88,783 2023 22,997 2024 16,222 2025 and thereafter 15,765 Total $ 562,964

Short-term Borrowings (Tables)

Short-term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2020
Short-term Debt [Abstract]
Summary of Short-Term Borrowings	Short-term borrowings at December 31 were as follows: 2020 2019 2018 Ending Average Average Ending Average Average Ending Average Average (dollars in thousands) Federal funds purchased $ — $ 4,147 1.06 % $ — $ 8,069 2.53 % $ 11,000 $ 8,801 2.05 % Borrowings from FHLB — 28,252 1.54 136,200 278,930 2.62 565,000 467,594 2.12 Securities sold under agreements to repurchase 117,373 110,235 0.21 65,653 104,548 0.75 145,823 142,562 0.44 Total $ 117,373 $ 142,634 0.49 $ 201,853 $ 391,547 2.12 $ 721,823 $ 618,957 1.74 Maximum total at any month-end $ 248,471 $ 670,831 $ 811,026 Weighted average rate at year-end 0.10 % 1.41 % 2.17 %
Interest Expense on Short-Term Borrowings	Interest expense on short-term borrowings for the years ended December 31 is detailed below: 2020 2019 2018 (dollars in thousands) Federal funds purchased $ 44 $ 204 $ 180 Borrowings from FHLB 434 7,313 9,929 Securities sold under agreements to repurchase 226 781 632 Total interest on short-term borrowings $ 704 $ 8,298 $ 10,741

Subordinated Debentures (Tables

Subordinated Debentures (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Subordinated Debentures [Abstract]
Subordinated Debentures Outstanding	Subordinated debentures outstanding at December 31 are as follows: 2020 2019 Due Amount Rate Amount Rate (dollars in thousands) Owed to: First Commonwealth Bank 06/01/2028 $ 49,314 4.875% until June 1, 2023, then LIBOR + 1.845% $ 49,222 4.875% until June 1, 2023, then LIBOR + 1.845% First Commonwealth Bank 06/01/2033 49,131 5.50% until June 1, 2028, 49,061 5.50% until June 1, 2028, First Commonwealth Capital Trust II 01/23/2034 30,929 LIBOR + 2.85 30,929 LIBOR + 2.85 First Commonwealth Capital Trust III 04/06/2034 41,238 LIBOR + 2.85 41,238 LIBOR + 2.85 Total $ 170,612 $ 170,450

Other Long-term Debt (Tables)

Other Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Summary of Other Long-Term Debt	Other long-term debt at December 31 follows: 2020 2019 Amount Weighted Amount Weighted (dollars in thousands) Borrowings from FHLB due: 2020 $ 659 3.84 % 2021 $ 50,685 2.32 % 50,685 2.32 2022 712 3.85 712 3.85 2023 739 3.86 739 3.86 2024 769 3.86 769 3.86 2025 799 3.86 Thereafter 2,554 3.74 3,353 3.77 Total $ 56,258 $ 56,917

Fair Values of Assets and Lia_2

Fair Values of Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Quantitative Inputs and Assumptions Used in Level 3 Fair Value Measurements	In accordance with ASU 2011-4, the following table provides information related to quantitative inputs and assumptions used in Level 3 fair value measurements. Fair Value Valuation Technique Unobservable Inputs Range / (weighted December 31, 2020 Other Investments $ 1,670 Carrying Value N/A N/A Nonperforming Loans 798 (a) Gas Reserve study Discount rate 10.00% Gas per MMBTU $1.46 - $1.48 (b) Oil per BBL/d $36 - $36 (b) Limited Partnership Investments 6,619 Par Value N/A N/A December 31, 2019 Other Investments 1,670 Carrying Value N/A N/A Nonperforming Loans 884 (a) Gas Reserve study Discount rate 10.00% Gas per MMBTU $2.61 - $3.49 (b) Oil per BBL/d $47.09 - $53.14 (b) 2,239 (a) Discounted Cash Flow Discount Rate 3.84% - 9.50% Limited Partnership Investments 5,795 Par Value N/A N/A (a) the remainder of nonperforming loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation.
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The tables below present the balances of assets and liabilities measured at fair value on a recurring basis at December 31: 2020 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 7,230 $ — $ 7,230 Mortgage-Backed Securities—Commercial — 191,180 — 191,180 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 496,033 — 496,033 Other Government-Sponsored Enterprises — 100,998 — 100,998 Obligations of States and Political Subdivisions — 11,397 — 11,397 Corporate Securities — 24,385 — 24,385 Total Securities Available for Sale — 831,223 — 831,223 Other Investments — 10,557 1,670 12,227 Loans Held for Sale — 33,436 — 33,436 Premises and Equipment — 442 — 442 Other Assets (a) — 54,362 6,619 60,981 Total Assets $ — $ 930,020 $ 8,289 $ 938,309 Other Liabilities (a) $ — $ 61,308 $ — $ 61,308 Total Liabilities $ — $ 61,308 $ — $ 61,308 (a) Hedging and non-hedging interest rate derivatives and limited partnership investments 2019 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 8,341 $ — $ 8,341 Mortgage-Backed Securities—Commercial — 189,133 — 189,133 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 661,947 — 661,947 Other Government-Sponsored Enterprises — 1,000 — 1,000 Obligations of States and Political Subdivisions — 17,909 — 17,909 Corporate Securities — 23,962 — 23,962 Total Securities Available for Sale — 902,292 — 902,292 Other Investments — 15,091 1,670 16,761 Loans Held for Sale — 15,989 — 15,989 Other Assets (a) — 21,894 5,795 27,689 Total Assets $ — $ 955,266 $ 7,465 $ 962,731 Other Liabilities (a) $ — $ 21,469 $ — $ 21,469 Total Liabilities $ — $ 21,469 $ — $ 21,469
Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis	The changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows for the year ended December 31, 2020: Other Investments Other Assets Total (dollars in thousands) Balance, beginning of year $ 1,670 $ 5,795 $ 7,465 Total gains or losses Included in earnings — — — Included in other comprehensive income — — — Purchases, issuances, sales, and settlements Purchases — 824 824 Issuances — — — Sales — — — Settlements — — — Transfers from Level 3 — — — Transfers into Level 3 — — — Balance, end of year $ 1,670 $ 6,619 $ 8,289 There are no gains or losses included in earnings for the period that are attributable to the change in realized gains (losses) relating to assets held at December 31, 2020. During the year ended December 31, 2020, there were no transfers between fair value Levels 1, 2 or 3. The changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows for the year ended December 31, 2019: Other Investments Other Assets Total (dollars in thousands) Balance, beginning of year $ 1,670 $ 2,696 $ 4,366 Total gains or losses Included in earnings — 198 198 Included in other comprehensive income — — — Purchases, issuances, sales, and settlements Purchases — 2,956 2,956 Issuances — — — Sales — — — Settlements — (55) (55) Transfers from Level 3 — — — Transfers into Level 3 — — — Balance, end of year $ 1,670 $ 5,795 $ 7,465
Schedule of Assets Measured on Nonrecurring Basis	The tables below present the balances of assets measured at fair value on a nonrecurring basis at December 31 and total gains and losses realized on these assets during the year ended December 31: 2020 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Nonperforming loans $ — $ 35,543 $ 13,604 $ 49,147 $ (7,905) Other real estate owned — 1,319 — 1,319 (30) Total Assets $ — $ 36,862 $ 13,604 $ 50,466 $ (7,935) 2019 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Nonperforming loans $ — $ 12,267 $ 17,518 $ 29,785 $ (2,667) Other real estate owned — 2,608 — 2,608 (196) Total Assets $ — $ 14,875 $ 17,518 $ 32,393 $ (2,863)
Carrying Amounts and Fair Values of Financial Instruments	The following table presents carrying amounts and estimated fair values of First Commonwealth’s financial instruments at December 31: 2020 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 100,009 $ 100,009 $ 100,009 $ — $ — Interest-bearing deposits 256,572 256,572 256,572 — — Securities available for sale 831,223 831,223 — 831,223 — Securities held to maturity 361,844 369,851 — 369,851 — Other investments 12,227 12,227 — 10,557 1,670 Loans held for sale 33,436 33,436 — 33,436 — Loans 6,761,183 7,202,763 — 35,543 7,167,220 Financial liabilities Deposits 7,438,666 7,440,906 — 7,440,906 — Short-term borrowings 117,373 117,037 — 117,037 — Long-term debt 56,258 57,881 — 57,881 — Subordinated debt 170,612 165,665 — — 165,665 Capital lease obligation 6,385 6,385 — 6,385 — 2019 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 102,346 $ 102,346 $ 102,346 $ — $ — Interest-bearing deposits 19,510 19,510 19,510 — — Securities available for sale 902,292 902,292 — 902,292 — Securities held to maturity 337,123 338,718 — 338,718 — Other investments 16,761 16,761 — 15,091 1,670 Loans held for sale 15,989 15,989 — 15,989 — Loans 6,189,148 6,393,872 — 12,267 6,381,605 Financial liabilities Deposits 6,677,615 6,677,595 — 6,677,595 — Short-term borrowings 201,853 201,151 — 201,151 — Long-term debt 56,917 58,051 — 58,051 — Subordinated debt 170,450 171,772 — — 171,772 Capital lease obligation 6,815 6,815 — 6,815 —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Provision (Benefit)	The income tax provision for the years ended December 31 is as follows: 2020 2019 2018 (dollars in thousands) Current tax provision: Federal $ 21,629 $ 22,942 $ 21,330 State 329 282 298 Total current tax provision 21,958 23,224 21,628 Deferred tax provision (benefit): Federal (5,070) 2,284 3,666 State (132) 8 (20) Total deferred tax provision (5,202) 2,292 3,646 Total tax provision $ 16,756 $ 25,516 $ 25,274
Schedule of Effective Income Tax Rate Reconciliation	The statutory to effective tax rate reconciliation for the years ended December 31 is as follows: 2020 2019 2018 Amount % of Amount % of Amount % of (dollars in thousands) Tax at statutory rate $ 18,943 21 % $ 27,478 21 % $ 27,882 21 % Increase (decrease) resulting from: State income tax, net of federal benefit 155 — 229 — 220 — Income from bank owned life insurance (1,376) (1) (1,260) (1) (1,404) (1) Tax-exempt interest income, net (1,117) (1) (1,298) (1) (1,473) (1) Tax credits (44) — (7) — (5) — Enactment of federal tax reform — — — — (346) — Other 195 — 374 — 400 — Total tax provision $ 16,756 19 % $ 25,516 19 % $ 25,274 19 %
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences between the financial statement carrying amounts and the tax bases of assets and liabilities that represent significant portions of the deferred tax assets and liabilities at December 31 are presented below: 2020 2019 (dollars in thousands) Deferred tax assets: Lease liability $ 9,928 $ 11,203 Allowance for credit losses 21,483 10,937 Postretirement benefits other than pensions 242 275 Alternative minimum tax credit carryforward — 216 Net operating loss carryforward 385 2,017 Deferred compensation 1,723 1,720 Accrued interest on nonaccrual loans 644 710 Accrued incentives 2,182 2,185 Unfunded loan commitments & other reserves 1,576 964 Other 1,831 1,032 Total deferred tax assets 39,994 31,259 Deferred tax liabilities: Loan origination fees and costs (1,280) (626) Right of use asset $ (9,037) $ (10,302) Unrealized gain on securities available for sale (4,629) (1,386) Depreciation of assets (2,103) (1,470) Section 197 intangibles (540) (45) Other (424) (568) Total deferred tax liabilities (18,013) (14,397) Net deferred tax asset $ 21,981 $ 16,862

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Schedule of Components of Net Periodic Benefit Cost	Net periodic benefit cost of these plans for the years ended December 31, was as follows: 2020 2019 2018 (dollars in thousands) Service cost $ — $ — $ — Interest cost on projected benefit obligation 23 34 38 Amortization of transition obligation — — — Gain amortization (52) (60) (35) Net periodic benefit cost $ (29) $ (26) $ 3
Schedule of Changes in Benefit Obligations and Plan Assets	The following table sets forth the change in the benefit obligation and plan assets as of December 31: 2020 2019 (dollars in thousands) Change in Benefit Obligation Benefit obligation at beginning of year $ 834 $ 883 Service cost — — Interest cost 23 34 Amendments 537 — Actuarial gain 102 61 Net benefits paid (124) (144) Benefit obligation at end of year 1,372 834 Change in Plan Assets Fair value of plan assets at beginning of year — — Actual return on plan assets — — Employer contributions 124 144 Net benefits paid (124) (144) Fair value of plan assets at end of year — — Funded Status at End of Year 1,372 834 Unrecognized prior service cost (537) — Unrecognized net gain 308 463 Amounts recognized in retained earnings $ 1,143 $ 1,297
Schedule of Amounts Recognized as Other Liabilities	As of December 31, the funded status of the plan is: 2020 2019 (dollars in thousands) Amounts Recognized in the Statement of Financial Condition as Other liabilities $ 1,372 $ 834
Schedule of Amounts Recognized in Accumulated Other Comprehensive Income	The following table identifies the related tax effects allocated to each component of other comprehensive income in the Consolidated Statements of Comprehensive Income as of December 31. Reclassification adjustments related to securities available for sale are included in the “ Net securities gains ” line in the Consolidated Statements of Income and reclassification adjustments related to losses on derivatives are included in the "Other operating expenses" line in the Consolidated Statements of Income. 2020 2019 2018 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains (losses) on securities: Unrealized holding gains on securities arising during the period $ 19,981 $ (4,196) $ 15,785 $ 20,625 $ (4,331) $ 16,294 $ 2,783 $ (585) $ 2,198 Reclassification adjustment for gains on securities included in net income (70) 15 (55) (22) 5 (17) (8,102) 1,701 (6,401) Total unrealized gains (losses) on securities 19,911 (4,181) 15,730 20,603 (4,326) 16,277 (5,319) 1,116 (4,203) Unrealized gains (losses) on derivatives: Unrealized holding (losses) gains on derivatives arising during the period (4,467) 938 (3,529) 935 (196) 739 326 (68) 258 Reclassification adjustment for losses on derivatives included in net income — — — — — — 10 (3) 7 Total unrealized (losses) gains on derivatives (4,467) 938 (3,529) 935 (196) 739 336 (71) 265 Unrealized (losses) gains for postretirement obligations: Prior service cost (537) 113 (424) — — — — — — Net (loss) gain (155) 32 (123) (121) 25 (96) 144 (30) 114 Total unrealized (losses) gains for postretirement obligations (692) 145 (547) (121) 25 (96) 144 (30) 114 Total other comprehensive income (loss) $ 14,752 $ (3,098) $ 11,654 $ 21,417 $ (4,497) $ 16,920 $ (4,839) $ 1,015 $ (3,824) The following table sets forth the amounts recognized in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit costs as of December 31: 2020 2019 2018 (dollars in thousands) Amounts recognized in accumulated other comprehensive income, net of tax: Net (gain) loss $ (243) $ (366) $ (461) Prior service cost 424 — — Total $ 181 $ (366) $ (461)
Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligation	Weighted-average assumptions used to determine the benefit obligation as of December 31 are as follows: 2020 2019 2018 Weighted-Average Assumptions Discount rate 1.83 % 2.88 % 4.11 % Health care cost trend: Initial 5.95 % 5.55 % 6.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2026 2025 2024
Schedule of Weighted-Average Assumptions Used to Determine Net Periodic Cost	Weighted-average assumptions used to determine the benefit obligation as of December 31 are as follows: 2020 2019 2018 Weighted-Average Assumptions Discount rate 1.83 % 2.88 % 4.11 % Health care cost trend: Initial 5.95 % 5.55 % 6.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2026 2025 2024 Weighted-average assumptions used to determine the net benefit costs as of December 31 are as follows: 2020 2019 2018 Weighted-Average Assumptions for Net Periodic Cost Discount rate 2.88 % 4.11 % 3.37 % Health care cost trend: Initial 5.55 % 6.00 % 6.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2025 2024 2023 Corridor 10.00 % 10.00 % 10.00 % Recognition period for gains and losses 10.9 12.1 12.1
Schedule of Impact of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates	The health care cost trend rate assumption can have a significant impact on the amounts reported for this plan. A one-percentage-point change in assumed health care cost trend rates would have the following effects: One-Percentage- One-Percentage- (dollars in thousands) Effect on postretirement benefit obligation $ 30 $ (29) Effect on total of service and interest cost components 1 —
Schedule of Projected Benefit Payments	As of December 31, 2020, the projected benefit payments for the next ten years are as follows: Projected Benefit (dollars in thousands) 2021 $ 165 2022 157 2023 147 2024 136 2025 124 2026 - 2030 455
Schedule of Amounts Recognized in Accumulated Other Comprehensive Income	The estimated costs that will be amortized from accumulated other comprehensive income into net periodic cost for 2021 are as follows (dollars in thousands): Postretirement (dollars in thousands) Net gain $ (27) Prior service cost 76 Total $ 49

Incentive Compensation Plan (Ta

Incentive Compensation Plan (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	The following provides detail on the restricted stock awards which were issued and outstanding in 2020, 2019 and 2018 in order to retain and attract key employees. The grant date fair value of the restricted stock awards is equal to the price of First Commonwealth’s common stock on grant date. Grant Date Shares issued Grant Price Vesting Date Number of Equal Vesting Periods February 20, 2020 95,300 $ 13.72 February 20, 2023 1 February 21, 2019 63,000 14.22 February 22, 2022 1 February 21, 2019 15,000 14.22 February 22, 2022 1 November 26, 2018 2,000 13.82 November 26, 2021 1 May 29, 2018 3,000 15.44 May 29, 2021 1 March 26, 2018 2,000 14.08 March 26, 2021 1 February 26, 2018 77,500 14.49 February 26, 2021 1 March 24, 2017 5,000 12.99 March 24, 2020 1 March 24, 2017 7,000 12.99 March 24, 2020 1 December 19, 2016 15,000 13.96 December 19, 2019 3 September 30, 2016 10,000 10.09 September 30, 2019 1 September 19, 2016 33,000 10.02 September 19, 2019 3 June 7, 2016 10,000 9.34 June 7, 2019 1 March 1, 2016 10,000 8.84 March 1, 2019 1 March 1, 2016 5,000 8.84 March 1, 2019 1 June 26, 2015 1,000 9.84 June 26, 2018 1 February 5, 2015 50,000 8.55 February 5, 2018 1
Unvested Service-Based Restricted Stock Awards	A summary of the status of First Commonwealth’s unvested service-based restricted stock awards as of December 31 and changes for the years ended on those dates is presented below: 2020 2019 2018 Shares Weighted Shares Weighted Shares Weighted Outstanding, beginning of the year 171,500 $ 14.27 137,500 $ 13.05 117,000 $ 9.99 Granted 95,300 13.72 78,000 14.22 84,500 14.50 Vested (12,000) — (41,000) 10.09 (54,000) 9.37 Forfeited (4,000) 13.85 (3,000) 14.40 (10,000) 9.34 Outstanding, end of the year 250,800 14.13 171,500 14.27 137,500 13.05
Schedule of Restricted Stock Units Granted Based on Performance [Table Text Block]	The following provides detail on restricted stock awards estimated to be granted on a performance award basis during 2020, 2019 and 2018. These plans were previously approved by the Board of Directors. Grant Date Target Share Award Performance Period (years) Award if threshold met Award if targets are met Award if superior met Award if threshold not achieved Vesting After Performance Period (years) Final vesting December 30, 2015 60,000 5 0 December 31, 2020 February 18, 2016 160,650 3 40 % 100 % 200 % — % 0 December 31, 2018 February 23, 2017 93,500 3 40 % 100 % 200 % — % 0 December 31, 2019 February 22, 2018 102,000 3 40 % 100 % 200 % — % 0 December 31, 2020 February 21, 2019 121,900 3 40 % 100 % 200 % — % 0 December 31, 2021 February 20, 2020 188,700 3 40 % 100 % 200 % — % 0 December 31, 2022
Unvested Target Award	The following table summarizes the estimated unvested target share awards for the Plans as of December 31: 2020 2019 2018 Outstanding, beginning of the year 442,832 496,603 525,045 Granted 188,700 134,929 130,995 Issued (134,452) (188,700) (149,480) Forfeited — — (9,957) Outstanding, end of the year 497,080 442,832 496,603

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue Recognition and Deferred Revenue [Abstract]
Disaggregation of Revenue [Table Text Block]	The following presents noninterest income, segregated by revenue streams in-scope and out-of-scope of Topic 606 for the year ended December 31: 2020 2019 2018 (dollars in thousands) Noninterest Income In-scope of Topic 606: Trust income $ 9,101 $ 8,321 $ 7,901 Service charges on deposit accounts 16,387 18,926 18,175 Insurance and retail brokerage commissions 7,850 7,583 7,426 Card-related interchange income 23,966 21,677 20,187 Gain on sale of other loans and assets 967 1,062 982 Other income 3,675 3,837 3,708 Noninterest Income (in-scope of Topic 606) 61,946 61,406 58,379 Noninterest Income (out-of-scope of Topic 606) 32,530 24,079 30,258 Total Noninterest Income $ 94,476 $ 85,485 $ 88,637

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Loans to Related Parties	The following is an analysis of loans to related parties (dollars in thousands): December 31, 2019 $ 19,246 Advances 4,258 Repayments (3,931) December 31, 2020 $ 19,573

Regulatory Restrictions and C_2

Regulatory Restrictions and Capital Adequacy (Tables)	12 Months Ended
	Dec. 31, 2020
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Schedule of Capital Amount and Ratio Considered to be Capitalized	as set forth in the tables below: Actual Minimum Capital Required Required to be Considered Well Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2020 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 1,010,608 14.88 % $ 713,289 10.50 % $ 679,323 10.00 % First Commonwealth Bank 974,911 14.36 712,995 10.50 679,043 10.00 Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 827,231 12.18 % $ 577,424 8.50 % $ 543,458 8.00 % First Commonwealth Bank 791,568 11.66 577,186 8.50 543,234 8.00 Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 827,231 9.40 % $ 352,023 4.00 % $ 440,029 5.00 % First Commonwealth Bank 791,568 9.01 351,244 4.00 439,055 5.00 Common Equity Tier I to Risk Weighted Assets First Commonwealth Financial Corporation $ 757,231 11.15 % $ 475,526 7.00 % $ 441,560 6.50 % First Commonwealth Bank 791,568 11.66 475,330 7.00 441,378 6.50 Actual Minimum Capital Required Required to be Considered Well Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2019 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 954,991 14.26 % $ 703,370 10.50 % $ 669,877 10.00 % First Commonwealth Bank 913,863 13.67 702,006 10.50 668,577 10.00 Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 800,526 11.95 % $ 569,395 8.50 % $ 535,901 8.00 % First Commonwealth Bank 759,398 11.36 568,291 8.50 534,862 8.00 Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 800,526 10.17 % $ 314,963 4.00 % $ 393,704 5.00 % First Commonwealth Bank 759,398 9.66 314,338 4.00 392,922 5.00 Common Equity Tier I to Risk Weighted Assets First Commonwealth Financial Corporation $ 730,526 10.91 % $ 468,914 7.00 % $ 435,420 6.50 % First Commonwealth Bank 759,398 11.36 468,004 7.00 434,575 6.50

Condensed Financial Informati_2

Condensed Financial Information of First Commonwealth Financial Corporation (parent company only) (Tables)	12 Months Ended
	Dec. 31, 2020
Condensed Financial Information Disclosure [Abstract]
Statements of Financial Condition	Statements of Financial Condition December 31, 2020 2019 (dollars in thousands) Assets Cash $ 34,427 $ 22,889 Loans 11 13 Investment in subsidiaries 1,108,801 1,086,844 Investment in unconsolidated subsidiary trusts 2,182 2,190 Investment in jointly-owned company 338 306 Premises and equipment, net 3,476 3,801 Receivable from subsidiaries — 4,750 Dividends receivable from subsidiaries 3,038 5,097 Other assets 7,307 6,924 Total assets $ 1,159,580 $ 1,132,814 Liabilities and Shareholders’ Equity Accrued expenses and other liabilities $ 18,796 $ 4,983 Subordinated debentures payable 72,167 72,167 Shareholders’ equity 1,068,617 1,055,664 Total liabilities and shareholders’ equity $ 1,159,580 $ 1,132,814
Statements of Operations	Statements of Income For the years ended December 31, 2020 2019 2018 (dollars in thousands) Interest and dividends $ 8 $ 8 $ 1 Dividends from subsidiaries 61,708 55,964 81,851 Interest expense (3,229) (3,735) (3,722) Other income 3 6 14 Operating expense (4,687) (4,525) (4,047) Income before taxes and equity in undistributed earnings of subsidiaries 53,803 47,718 74,097 Applicable income tax benefits 1,648 1,720 1,324 Income before equity in undistributed earnings of subsidiaries 55,451 49,438 75,421 Equity in undistributed earnings of subsidiaries 17,996 55,895 32,077 Net income $ 73,447 $ 105,333 $ 107,498
Statements of Cash Flow	For the years ended December 31, Statements of Cash Flow 2020 2019 2018 (dollars in thousands) Operating Activities Net income $ 73,447 $ 105,333 $ 107,498 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 383 340 320 Net gains on sales of assets — (2) (7) Decrease (increase) in prepaid income taxes (317) 629 37 Undistributed equity in subsidiaries (17,996) (55,895) (32,077) Distribution from unconsolidated subsidiary — — 9,000 Other net 19,705 (2,957) (1,628) Net cash provided by operating activities 75,222 47,448 83,143 Investing Activities Net change in loans 1 1 3 Purchases of premises and equipment (20) (586) (87) Proceeds from sale of other assets — 2 7 Investment in subsidiaries — — (17,202) Net cash used in by investing activities (19) (583) (17,279) Financing Activities Dividends paid (42,982) (39,394) (34,849) Proceeds from reissuance of treasury stock 222 211 208 Purchase of treasury stock (20,905) (6,259) (26,189) Net cash used in financing activities (63,665) (45,442) (60,830) Net increase (decrease) in cash 11,538 1,423 5,034 Cash at beginning of year 22,889 21,466 16,432 Cash at end of year $ 34,427 $ 22,889 $ 21,466

Statement of Accounting Polic_3

Statement of Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020USD ($)Segmentcounty	Dec. 31, 2019USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of counties in which entity provides services | county	26
Business segments | Segment	1
Equity investments	20.00%
Loans past due days	90 days
Excess impaired credits	$ 250,000
Software purchases and developed are capitalized and amortized on straight-line basis	7 years
Guaranteed Minimum Death Benefit [Member]
Summary Of Significant Accounting Policies [Line Items]
Other liabilities	$ 4,600,000	$ 4,200,000

Acquisition - Narrative (Detail

Acquisition - Narrative (Details) - USD ($) $ in Thousands	Sep. 06, 2019	Apr. 03, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired			$ 0	$ (332,468)	$ (705)
Merger and acquisition related			0	3,536	$ 1,637
Goodwill			303,328	$ 303,328
Santander Bank, N.A. [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 329,533
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	$ 112,913
Business Combination, Acquired Receivables, Gross Contractual Amount	101,200
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Deposits	471,386
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Deposits Gross	471,000
Goodwill, Acquired During Period	29,126
Merger and acquisition related			$ 3,700
Loans	99,956
Business Combination, Acquired Receivables, Fair Value Adjustment	1,200
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Deposits Fair Value Adj	400
Core deposit intangible	$ 5,615

Acquisition - Summary (Details)

Acquisition - Summary (Details) - USD ($) $ in Thousands	Sep. 06, 2019	Apr. 03, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value of Liabilities Assumed
Payments to Acquire Businesses, Net of Cash Acquired			$ 0	$ (332,468)	$ (705)
Santander Bank, N.A. [Member]
Fair Value of Assets Acquired
Cash and cash equivalents	$ 2,935
Loans	99,956
Premises and other equipment	3,637
Core deposit intangible	5,615
Other assets	770
Total assets acquired	112,913
Fair Value of Liabilities Assumed
Deposits	471,386
Other Liabilities	186
Total liabilities assumed	471,572
Total Fair Value of Identifiable Net Assets	(358,659)
Goodwill, Acquired During Period	$ 29,126
Payments to Acquire Businesses, Net of Cash Acquired		$ 329,533

Supplemental Comprehensive In_3

Supplemental Comprehensive Income Disclosures - Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized holding gains on securities arising during the period	$ 19,981	$ 20,625	$ 2,783
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	4,196	4,331	585
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	15,785	16,294	2,198
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	70	22	8,102
Less: reclassification adjustment for (gains) losses on securities included in net income, Tax (Expense) Benefit	15	5	1,701
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	55	17	6,401
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	19,911	20,603	(5,319)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	4,181	4,326	(1,116)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	15,730	16,277	(4,203)
Unrealized holding (losses) gains on derivatives arising during the period	(4,467)	935	326
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(938)	196	68
Unrealized holding gains on derivatives arising during the period, Net of Tax Amount	(3,529)	739	258
Reclassification adjustment for gains on derivatives included in net income, Pretax Amount	0	0	(10)
Reclassification adjustment for gains on derivatives included in net income, Tax (Expense) Benefit	0	0	(3)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	0	(7)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax	(4,467)	935	336
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(938)	196	71
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(3,529)	739	265
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	(537)	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax	113	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	424	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	155	121	(144)
Net (loss) gain, Tax (Expense) Benefit	32	25	(30)
Net gain	(123)	(96)	114
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	692	121	(144)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	145	25	(30)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	547	96	(114)
Total other comprehensive (loss) income, Pretax Amount	14,752	21,417	(4,839)
Other Comprehensive Income (Loss), Tax	3,098	4,497	(1,015)
Total other comprehensive (loss) Income	11,654	16,920	(3,824)
Post-Retirement Obligation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	(424)
Net gain	(123)
Total other comprehensive (loss) Income	$ (547)	$ (96)	$ 114

Supplemental Comprehensive In_4

Supplemental Comprehensive Income Disclosures Supplemental Comprehensive Income Disclosures (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period	$ 5,579	$ (11,341)	$ (6,173)
Cumulative Effect of New Accounting Principle in Period of Adoption	11,199			$ (1,344)
Other comprehensive income before reclassification adjustment	12,256	17,033	2,456
Amounts reclassified from accumulated other comprehensive income (loss)	(55)	(17)	(6,394)
Net gain		(96)	114
Net other comprehensive income during the period	11,654	16,920	(3,824)
Balance at end of period	17,233	5,579	(11,341)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	(424)	0	0
Net gain	(123)	(96)	114
Securities Available for Sale
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period		(11,697)	(6,166)
Cumulative Effect of New Accounting Principle in Period of Adoption				(1,328)
Other comprehensive income before reclassification adjustment	15,785	16,294	2,198
Amounts reclassified from accumulated other comprehensive income (loss)	(55)	(17)	(6,401)
Net other comprehensive income during the period	15,730	16,277	(4,203)
Balance at end of period	20,310		(11,697)
AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member]
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period		(105)	(306)
Cumulative Effect of New Accounting Principle in Period of Adoption				(64)
Other comprehensive income before reclassification adjustment	(3,529)	739	258
Amounts reclassified from accumulated other comprehensive income (loss)	0	0	7
Net other comprehensive income during the period	(3,529)	739	265
Balance at end of period	(2,895)		(105)
Post-Retirement Obligation
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period		461	299
Cumulative Effect of New Accounting Principle in Period of Adoption				48
Net gain		(96)	114
Net other comprehensive income during the period	(547)	(96)	114
Balance at end of period	(182)		461
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	424
Net gain	(123)
Accumulated Other Comprehensive Income (Loss), net [Member]
Accumulated Other Comprehensive Income [Line Items]
Net other comprehensive income during the period	11,654	16,920	(3,824)
Previously Reported [Member]
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period	5,579
Balance at end of period		5,579
Previously Reported [Member] | Securities Available for Sale
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period	4,580
Balance at end of period		4,580
Previously Reported [Member] | AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member]
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period	634
Balance at end of period		634
Previously Reported [Member] | Post-Retirement Obligation
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period	$ 365
Balance at end of period		$ 365
Accounting Standards Update 2018-02 [Member]
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period			(7,517)
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Accounting Standards Update 2018-02 [Member] | Securities Available for Sale
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period			(7,494)
Accounting Standards Update 2018-02 [Member] | AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member]
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period			(370)
Accounting Standards Update 2018-02 [Member] | Post-Retirement Obligation
Accumulated Other Comprehensive Income [Line Items]
Balance at beginning of period			$ 347
Accounting Standards Update 2018-02 [Member] | Accumulated Other Comprehensive Income (Loss), net [Member]
Accumulated Other Comprehensive Income [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ (1,344)

Supplemental Cash Flow Disclo_3

Supplemental Cash Flow Disclosures - Non-cash Investing and Financing Activities (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash paid during the year for:
Interest	$ 33,964,000	$ 56,005,000	$ 40,071,000
Income taxes	25,914,000	21,787,000	23,826,000
Non-cash investing and financing activities:
Real Estate Owned, Transfer to Real Estate Owned	3,865,000	4,723,000	4,334,000
Fair value of loans transferred from held to maturity to available for sale	37,305,000	30,359,000	37,367,000
Transfer of Loans Held-for-sale to Portfolio Loans	4,335,000	482,000	0
Gross (decrease) increase in market value adjustment to securities available for sale	19,911,000	20,604,000	(5,319,000)
Gross (decrease) increase in market value adjustment to derivatives	(4,467,000)	935,000	336,000
Investments Committed to Purchase, Not Yet Paid	(34,185,000)	25,484,000	0
Increase in Commitment to Limited Partnership	0	1,469,000	0
Noncash or Part Noncash Acquisition, Value of Assets Acquired	0	(361,595,000)	(21,834,000)
Other Significant Noncash Transaction, Consideration Received	(384,000)	484,000	0
Treasury stock reissued	$ 1,594,000	$ 2,531,000	$ 2,257,000

Earnings per Share - Compositio

Earnings per Share - Composition of Weighted-Average Common Shares (Denominator) Used in Basic and Diluted Earnings Per Share (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Weighted Average Number of Shares, Deferred Compensation Plans	42,751	37,496	37,411
Weighted average common shares issued	113,914,902	113,914,902	113,914,902
Average treasury shares	(16,254,304)	(15,447,299)	(14,747,687)
Average unearned nonvested shares	(118,261)	(112,320)	(93,641)
Weighted average common shares and common stock equivalents used to calculate basic earnings per share	97,499,586	98,317,787	99,036,163
Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share	203,836	231,957	149,939
Weighted average common shares and common stock equivalents used to calculate diluted earnings per share	97,758,965	98,588,164	99,223,513
Weighted Average Number Of Additional Shares Deferred Compensation Plan	55,543	38,420	37,411
Basic Earnings Per Share (in dollars per share)	$ 0.75	$ 1.07	$ 1.09
Diluted Earnings Per Share (in dollars per share)	$ 0.75	$ 1.07	$ 1.08

Earnings per Share - Common Sto

Earnings per Share - Common Stock Equivalents Not Included in Computation of Diluted Earnings Per Share (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	$ 1	$ 1
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	92,499	81,730	71,560
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	106,931	26,217	0
Minimum [Member] | Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	$ 13.72	$ 12.99	$ 8.84
Minimum [Member] | Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	12.43	16.62	0
Maximum [Member] | Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	15.44	15.44	14.49
Maximum [Member] | Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	$ 15.37	$ 16.62	$ 0

Cash and Due from Banks - Addit

Cash and Due from Banks - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Cash and Due from Banks [Abstract]
Cash or balances held with the Federal Reserve Bank	$ 173.2	$ 14.7

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Derivative	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Derivative [Line Items]
Number of participation agreements for interest rate swaps, participant | Derivative	36
Number of participation agreements for interest rate swaps, lead bank | Derivative	14
Derivative, Gain (Loss) on Derivative, Net	$ (2,521)	$ (269)	$ 787
Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	70,000	70,000
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	70,000	70,000
Interest Rate Swap [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(118)	(590)
Interest Rate Swap [Member] | Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	449	(159)	0
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Asset	2,100	4,800
Derivative, Notional Amount	2,119	4,789
Foreign Exchange Contract [Member] | Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	18	5	15
Forward Contracts [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Underlying Asset Carrying Value	25,000	9,800
Derivative Liability, Fair Value, Gross Asset	28,400	10,700
Derivative Liability, Notional Amount	47,900	25,500
Derivative, Notional Amount	65,000	30,000
Forward Contracts [Member] | Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	(189)
Other Income	420	$ 106	$ 0
2024 [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	30,000
2026 [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 40,000

Derivatives - Credit Value Adju

Derivatives - Credit Value Adjustment Recorded Related to Notional Amount of Derivatives Outstanding (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Credit value adjustment	$ (2,792)	$ (272)
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	631,446	587,275
Not Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Notional Amount	66,527	87,188
Not Designated as Hedging Instrument [Member] | Interest Rate Collar [Member]
Derivative [Line Items]
Derivative, Notional Amount	35,354	35,354
Not Designated as Hedging Instrument [Member] | Credit Default Swap, Buying Protection [Member]
Derivative [Line Items]
Derivative, Notional Amount	220,280	164,632
Not Designated as Hedging Instrument [Member] | Credit Default Swap, Selling Protection [Member]
Derivative [Line Items]
Derivative, Sold Protection Notional Amount	(78,522)	(69,011)
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	47,874	25,460
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Fair value adjustment	(3,665)	801
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	70,000	70,000
Designated as Hedging Instrument [Member] | Forward Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	65,000	30,000
Fair value adjustment	(483)	(63)
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	2,119	4,789
Fair value adjustment	$ (5)	$ (41)

Derivatives - Schedule of Chang

Derivatives - Schedule of Change in Fair Value of Derivative Assets and Liabilities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (2,521)	$ (269)	$ 787
Other Income [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(981)	(269)	787
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Net Hedge Ineffectiveness Gain (Loss)	0	(352)	(332)
Forward Contracts [Member] | Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	(189)
Other Income	420	106	0
Interest Rate Swap [Member] | Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	449	(159)	0
Other Expenses	0	7	10
Interest Rate Swap [Member] | Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(118)	(590)
Foreign Exchange Contract [Member] | Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 18	$ 5	$ 15

Investment Securities - Analysi

Investment Securities - Analysis of Amortized Cost and Estimated Fair Values of Securities Available for Sale (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Investment Securities [Line Items]
Amortized Cost	$ 805,515	$ 896,495
Gross Unrealized Gains	25,708	8,906
Gross Unrealized Losses	0	(3,109)
Securities available for sale	831,223	902,292
Estimated Fair Value, Less Than 12 Months	3,755	166,470
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(10)	(637)
Estimated Fair Value, 12 Months or More	0	235,380
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	(2,950)
Securities Continuous Unrealized Loss Position Fair Value	3,755	401,850
SecuritiesContinuousUnrealizedLossPositionAggregateLosses	(10)	(3,587)
US States and Political Subdivisions Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	11,154	17,738
Gross Unrealized Gains	243	171
Gross Unrealized Losses	0	0
Securities available for sale	11,397	17,909
Corporate Securities [Member]
Investment Securities [Line Items]
Amortized Cost	22,941	22,919
Gross Unrealized Gains	1,444	1,043
Gross Unrealized Losses	0	0
Securities available for sale	24,385	23,962
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage - Backed Securities - Residential [Member]
Investment Securities [Line Items]
Amortized Cost	481,109	660,777
Gross Unrealized Gains	14,924	4,113
Gross Unrealized Losses	0	(2,943)
Securities available for sale	496,033	661,947
Estimated Fair Value, Less Than 12 Months	3,755	111,969
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(10)	(436)
Estimated Fair Value, 12 Months or More	0	219,015
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	(2,801)
Securities Continuous Unrealized Loss Position Fair Value	3,755	330,984
SecuritiesContinuousUnrealizedLossPositionAggregateLosses	(10)	(3,237)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	100,996	1,000
Gross Unrealized Gains	2	0
Gross Unrealized Losses	0	0
Securities available for sale	100,998	1,000
Obligations of U.S. Government [Member] | Mortgage - Backed Securities - Commercial [Member]
Investment Securities [Line Items]
Amortized Cost	182,823	186,316
Gross Unrealized Gains	8,357	2,983
Gross Unrealized Losses	0	(166)
Securities available for sale	191,180	189,133
Estimated Fair Value, Less Than 12 Months		54,501
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses		(201)
Estimated Fair Value, 12 Months or More		16,365
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses		(149)
Securities Continuous Unrealized Loss Position Fair Value		70,866
SecuritiesContinuousUnrealizedLossPositionAggregateLosses		(350)
Obligations of U.S. Government [Member] | Mortgage - Backed Securities - Residential [Member]
Investment Securities [Line Items]
Amortized Cost	6,492	7,745
Gross Unrealized Gains	738	596
Gross Unrealized Losses	0	0
Securities available for sale	$ 7,230	$ 8,341

Investment Securities - Additio

Investment Securities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Security	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Debt Securities, Available-for-sale [Line Items]
Number of securities in an unrealized loss positions | Security	2
Corporate/Mortgage-Backed Securities, Amortized cost	$ 805,515	$ 896,495
Securities available for sale	831,223	902,292
Other than-temporary impairment charge		0	$ 9,164
Other investments	10,600	15,100
Equity Securities, FV-NI	1,700
Gross Unrealized Gains (Losses)	0	3,109
Amortized Cost	805,515	896,495
Held-to-maturity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	228,100	306,800
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Pledged Financial Instruments, Not Separately Reported, Other Debt Securities Available-for-sale or Held-for-investment	$ 792,100	584,800
Obligations of U.S. Government-Sponsored Enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Total unrealized losses	100.00%
Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost	$ 22,941	22,919
Securities available for sale	24,385	23,962
Gross Unrealized Gains (Losses)	0	0
Amortized Cost	22,941	22,919
Sales [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Gross Realized Losses	0	0	4,719
Available-for-sale Securities, Gross Realized Losses	0	7	0
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	0	(7)	4,719
Calls And Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Gains	70	29	3,383
Available-for-sale Securities, Gross Realized Losses	0	0	0
Gain Losses Maturities And Impairment	$ 70	$ 29	$ 3,383

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale (Detail) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Investment Securities [Line Items]
Due within 1 year, Amortized Cost		$ 104,995
Due after 1 but within 5 years, Amortized Cost		19,349
Due after 5 but within 10 years, Amortized Cost		10,747
Due after 10 years, Amortized Cost		0
Debt securities gross, Amortized Cost		135,091
Amortized Cost		805,515	$ 896,495
Total debt securities, Amortized Cost		805,515
Due within 1 year, Estimated Fair Value		105,015
Due after 1 but within 5 years, Estimated Fair Value		20,395
Due after 5 but within 10 years, Estimated Fair Value		11,370
Due after 10 years, Estimated Fair Value		0
Debt securities gross, Estimated Fair Value		136,780
Securities available for sale		831,223	$ 902,292
Total debt securities, Estimated Fair Value		831,223
Mortgage-Backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost	[1]	670,424
Securities available for sale	[1]	$ 694,443
[1]	Mortgage Backed Securities include an amortized cost of $189.3 million and a fair value of $198.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $481.1 million and a fair value of $496.0 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.

Investment Securities - Amort_2

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale, Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investment Securities [Line Items]
Amortized Cost	$ 805,515	$ 896,495
Securities available for sale	831,223	$ 902,292
US Government Agencies Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	189,300
Securities available for sale	198,400
Obligations of U.S. Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	481,100
Securities available for sale	$ 496,000

Investment Securities - Proceed

Investment Securities - Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Gain (Loss) on Securities [Line Items]
Proceeds from sale	$ 0	$ 948	$ 15,939
Net gains (losses) and impairment	70	22	8,102
Calls And Maturities [Member]
Gain (Loss) on Securities [Line Items]
Gross losses	0	0	0
Gross gains	70	29	3,383
Total gain (losses) maturities and impairment	70	29	3,383
Sales [Member]
Gain (Loss) on Securities [Line Items]
Gross losses	0	(7)	0
Available-for-sale Securities, Gross Realized Losses	0	0	4,719
Total gain (losses) from sales transactions	$ 0	$ (7)	$ 4,719

Investment Securities - Amort_3

Investment Securities - Amortized Cost and Fair Values of Debt Securities Held to Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 361,844	$ 337,123
Gross Unrealized Gains	8,017	2,073
Gross Unrealized Losses	(10)	(478)
Estimated Fair Value	369,851	338,718
Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	34,391	40,092
Gross Unrealized Gains	705	554
Gross Unrealized Losses	0	0
Estimated Fair Value	35,096	40,646
ERROR in label resolution.
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	800	600
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	800	600
Mortgage - Backed Securities - Commercial [Member] | Obligations of U.S. Government [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	36,799	51,291
Gross Unrealized Gains	1,441	18
Gross Unrealized Losses	0	(184)
Estimated Fair Value	38,240	51,125
Mortgage - Backed Securities - Commercial [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	9,737	12,081
Gross Unrealized Gains	344	67
Gross Unrealized Losses	0	0
Estimated Fair Value	10,081	12,148
Mortgage - Backed Securities - Residential [Member] | Obligations of U.S. Government [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,766	3,392
Gross Unrealized Gains	138	57
Gross Unrealized Losses	0	0
Estimated Fair Value	2,904	3,449
Mortgage - Backed Securities - Residential [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	277,351	229,667
Gross Unrealized Gains	5,389	1,377
Gross Unrealized Losses	(10)	(294)
Estimated Fair Value	$ 282,730	$ 230,750

Investment Securities - Schedul

Investment Securities - Schedule of Debt Securities Expected Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Amortized Cost
Due within 1 year		$ 2,500
Due after 1 but within 5 years		7,669
Due after 5 but within 10 years		20,126
Due after 10 years		4,896
Amortized Cost		35,191
Debt Securities, Held-to-maturity		361,844	$ 337,123
Estimated Fair Value
Due within 1 year		2,525
Due after 1 but within 5 years		7,742
Due after 5 but within 10 years		20,689
Due after 10 years		4,940
Estimated Fair Value		35,896
Securities held to maturity, fair value		369,851	$ 338,718
Mortgage-Backed Securities [Member]
Amortized Cost
Debt Securities, Held-to-maturity	[1]	326,653
Estimated Fair Value
Securities held to maturity, fair value	[1]	333,955
Mortgage-Backed Securities [Member] | US Government Agencies Debt Securities [Member]
Amortized Cost
Debt Securities, Held-to-maturity		39,600
Estimated Fair Value
Securities held to maturity, fair value		41,100
Mortgage-Backed Securities [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Amortized Cost
Debt Securities, Held-to-maturity		287,100
Estimated Fair Value
Securities held to maturity, fair value		$ 292,800
[1]	Mortgage Backed Securities include an amortized cost of $39.6 million and a fair value of $41.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $287.1 million and a fair value of $292.8 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.

Investment Securities - Sched_2

Investment Securities - Schedule of Unrealized Losses and Estimated Fair Values (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Estimated Fair Value, Less Than 12 Months	$ 3,755	$ 166,470
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(10)	(637)
Estimated Fair Value, 12 Months or More	0	235,380
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	(2,950)
Securities Continuous Unrealized Loss Position Fair Value	3,755	401,850
SecuritiesContinuousUnrealizedLossPositionAggregateLosses	(10)	(3,587)
Mortgage - Backed Securities - Residential [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Estimated Fair Value, Less Than 12 Months	3,755	111,969
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(10)	(436)
Estimated Fair Value, 12 Months or More	0	219,015
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	(2,801)
Securities Continuous Unrealized Loss Position Fair Value	3,755	330,984
SecuritiesContinuousUnrealizedLossPositionAggregateLosses	$ (10)	(3,237)
Mortgage - Backed Securities - Commercial [Member] | Obligations of U.S. Government [Member]
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Estimated Fair Value, Less Than 12 Months		54,501
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses		(201)
Estimated Fair Value, 12 Months or More		16,365
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses		(149)
Securities Continuous Unrealized Loss Position Fair Value		70,866
SecuritiesContinuousUnrealizedLossPositionAggregateLosses		$ (350)

Investment Securities - cumulat

Investment Securities - cumulative Roll Forward of Credit Losses Recognized in Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 0	$ 0	$ 12,208
Credit losses on debt securities for which other-than-temporary impairment was not previously recognized	0	0
Additional credit losses on debt securities for which other-than- temporary impairment was previously recognized	0	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Cash Flows	0	(223)
Reduction for debt securities called during the period	0	(9,164)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Securities Called	$ 0	$ (2,821)

Loans and Allowance for Credi_3

Loans and Allowance for Credit Losses - Outstanding Balances of Loan (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 6,761,183	$ 6,189,148	$ 5,774,139
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,555,986	1,241,853
Commercial, financial, agricultural and other [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,541,382
Commercial, financial, agricultural and other [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	14,604
Commercial, financial, agricultural and other [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,144,323
Commercial, financial, agricultural and other [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	606,269
Commercial, financial, agricultural and other [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	371,239
Commercial, financial, agricultural and other [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,421,151
Commercial, financial, agricultural and other [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	419,179
Commercial, financial, agricultural and other [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	712,800
Commercial, financial, agricultural and other [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	12,360
Commercial, financial, agricultural and other [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	90,655
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	427,221	449,039
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,750,592	1,681,362
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,211,569	2,117,519
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 815,815	699,375
Originated Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		5,714,373
Originated Loans [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,212,026
Originated Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		442,777
Originated Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,415,808
Originated Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,958,346
Originated Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		685,416
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		474,775
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		29,827
Acquired Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		6,262
Acquired Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		265,554
Acquired Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		159,173
Acquired Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 13,959

Loans and Allowance for Credi_4

Loans and Allowance for Credit Losses - Credit Risk Profile by Creditworthiness (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 6,761,183
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	6,458,370
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	226,634
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	76,179
Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	302,813
Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,555,986
Commercial, financial, agricultural and other [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	14,604
Commercial, financial, agricultural and other [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,541,382
Commercial, financial, agricultural and other [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,491,916
Commercial, financial, agricultural and other [Member] | Pass [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	14,604
Commercial, financial, agricultural and other [Member] | Pass [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,477,312
Commercial, financial, agricultural and other [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	48,233
Commercial, financial, agricultural and other [Member] | Special Mention [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Special Mention [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	48,233
Commercial, financial, agricultural and other [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	15,837
Commercial, financial, agricultural and other [Member] | Substandard [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Substandard [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	15,837
Commercial, financial, agricultural and other [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Doubtful [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Doubtful [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	64,070
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	64,070
Commercial, financial, agricultural and other [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Unlikely to be Collected Financing Receivable | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial, financial, agricultural and other [Member] | Unlikely to be Collected Financing Receivable | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	427,221
Real Estate Construction [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	426,663
Real Estate Construction [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	504
Real Estate Construction [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	54
Real Estate Construction [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Real Estate Construction [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	558
Real Estate Construction [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,750,592
Residential Real Estate [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,144,323
Residential Real Estate [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	606,269
Residential Real Estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,740,992
Residential Real Estate [Member] | Pass [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,138,409
Residential Real Estate [Member] | Pass [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	602,583
Residential Real Estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,902
Residential Real Estate [Member] | Special Mention [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,780
Residential Real Estate [Member] | Special Mention [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	122
Residential Real Estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	7,698
Residential Real Estate [Member] | Substandard [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	4,134
Residential Real Estate [Member] | Substandard [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,564
Residential Real Estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Residential Real Estate [Member] | Doubtful [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Residential Real Estate [Member] | Doubtful [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Residential Real Estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	9,600
Residential Real Estate [Member] | Total Non-Pass [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	5,914
Residential Real Estate [Member] | Total Non-Pass [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	3,686
Residential Real Estate [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Residential Real Estate [Member] | Unlikely to be Collected Financing Receivable | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Residential Real Estate [Member] | Unlikely to be Collected Financing Receivable | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	2,211,569
Commercial real estate [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	371,239
Commercial real estate [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,421,151
Commercial real estate [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	419,179
Commercial real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,983,258
Commercial real estate [Member] | Pass [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	369,883
Commercial real estate [Member] | Pass [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,216,252
Commercial real estate [Member] | Pass [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	397,123
Commercial real estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	175,995
Commercial real estate [Member] | Special Mention [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	131
Commercial real estate [Member] | Special Mention [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	161,336
Commercial real estate [Member] | Special Mention [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	14,528
Commercial real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	52,316
Commercial real estate [Member] | Substandard [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,225
Commercial real estate [Member] | Substandard [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	43,563
Commercial real estate [Member] | Substandard [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	7,528
Commercial real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Doubtful [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Doubtful [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Doubtful [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	228,311
Commercial real estate [Member] | Total Non-Pass [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,356
Commercial real estate [Member] | Total Non-Pass [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	204,899
Commercial real estate [Member] | Total Non-Pass [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	22,056
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Commercial real estate [Member] | Unlikely to be Collected Financing Receivable | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	815,815
Loans To Individuals [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	712,800
Loans To Individuals [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	12,360
Loans To Individuals [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	90,655
Loans To Individuals [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	815,541
Loans To Individuals [Member] | Pass [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	712,539
Loans To Individuals [Member] | Pass [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	12,360
Loans To Individuals [Member] | Pass [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	90,642
Loans To Individuals [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Special Mention [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Special Mention [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Special Mention [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	274
Loans To Individuals [Member] | Substandard [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	261
Loans To Individuals [Member] | Substandard [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Substandard [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	13
Loans To Individuals [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Doubtful [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Doubtful [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Doubtful [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	274
Loans To Individuals [Member] | Total Non-Pass [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	261
Loans To Individuals [Member] | Total Non-Pass [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Total Non-Pass [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	13
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0
Loans To Individuals [Member] | Unlikely to be Collected Financing Receivable | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 0
Originated Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		$ 5,714,373
Originated Loans [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		5,624,757
Originated Loans [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		43,393
Originated Loans [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		46,223
Originated Loans [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		89,616
Originated Loans [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		1,212,026
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		1,171,363
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		29,359
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		11,304
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		40,663
Originated Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		442,777
Originated Loans [Member] | Real Estate Construction [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		442,751
Originated Loans [Member] | Real Estate Construction [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		26
Originated Loans [Member] | Real Estate Construction [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Real Estate Construction [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Real Estate Construction [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		26
Originated Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		1,415,808
Originated Loans [Member] | Residential Real Estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		1,406,845
Originated Loans [Member] | Residential Real Estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		475
Originated Loans [Member] | Residential Real Estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		8,488
Originated Loans [Member] | Residential Real Estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Residential Real Estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		8,963
Originated Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		1,958,346
Originated Loans [Member] | Commercial real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		1,918,690
Originated Loans [Member] | Commercial real estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		13,533
Originated Loans [Member] | Commercial real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		26,123
Originated Loans [Member] | Commercial real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Commercial real estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		39,656
Originated Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		685,416
Originated Loans [Member] | Loans To Individuals [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		685,108
Originated Loans [Member] | Loans To Individuals [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Loans To Individuals [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		308
Originated Loans [Member] | Loans To Individuals [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Originated Loans [Member] | Loans To Individuals [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		308
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		474,775
Acquired Loans [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		463,784
Acquired Loans [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		5,183
Acquired Loans [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		5,808
Acquired Loans [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		10,991
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		29,827
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		27,696
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		2,009
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		122
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		2,131
Acquired Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		6,262
Acquired Loans [Member] | Real Estate Construction [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		5,697
Acquired Loans [Member] | Real Estate Construction [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		565
Acquired Loans [Member] | Real Estate Construction [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Real Estate Construction [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Real Estate Construction [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		565
Acquired Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		265,554
Acquired Loans [Member] | Residential Real Estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		262,630
Acquired Loans [Member] | Residential Real Estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		537
Acquired Loans [Member] | Residential Real Estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		2,387
Acquired Loans [Member] | Residential Real Estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Residential Real Estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		2,924
Acquired Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		159,173
Acquired Loans [Member] | Commercial real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		153,814
Acquired Loans [Member] | Commercial real estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		2,072
Acquired Loans [Member] | Commercial real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		3,287
Acquired Loans [Member] | Commercial real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Commercial real estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		5,359
Acquired Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		13,959
Acquired Loans [Member] | Loans To Individuals [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		13,947
Acquired Loans [Member] | Loans To Individuals [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Loans To Individuals [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		12
Acquired Loans [Member] | Loans To Individuals [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		0
Acquired Loans [Member] | Loans To Individuals [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		$ 12

Loans and Allowance for Credi_5

Loans and Allowance for Credit Losses - (Details) $ in Thousands	Dec. 31, 2020USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	$ 6,761,183
Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,667,389
Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,022,396
Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	792,402
Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	589,307
Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	462,092
Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,175,550
Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,052,047
Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,541,382
Time and demand loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	598,053
Time and demand loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	193,601
Time and demand loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	142,224
Time and demand loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	72,277
Time and demand loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	74,228
Time and demand loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	83,313
Time and demand loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	377,686
Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,604
Commercial credit cards | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Commercial credit cards | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Commercial credit cards | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Commercial credit cards | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Commercial credit cards | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Commercial credit cards | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Commercial credit cards | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,604
Real Estate Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	427,221
Real Estate Construction | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	150,493
Real Estate Construction | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	133,195
Real Estate Construction | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	104,167
Real Estate Construction | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	34,803
Real Estate Construction | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	389
Real Estate Construction | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,009
Real Estate Construction | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,165
Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,144,323
Senior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	316,052
Senior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	184,550
Senior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	142,823
Senior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	110,365
Senior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	91,495
Senior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	297,057
Senior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,981
Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	606,269
Junior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,055
Junior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	5,783
Junior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,545
Junior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	2,005
Junior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,303
Junior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	7,127
Junior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	582,451
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	371,239
Multifamily | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	76,249
Multifamily | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	16,287
Multifamily | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	69,439
Multifamily | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	66,963
Multifamily | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	34,383
Multifamily | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	106,328
Multifamily | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,590
Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,421,151
Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	105,861
Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	199,280
Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	161,018
Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	214,915
Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	217,883
Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	518,052
Nonowner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,142
Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	419,179
Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	59,519
Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	72,313
Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	61,079
Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	40,796
Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	27,415
Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	152,555
Owner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	5,502
Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	712,800
Automobile Loan | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	350,293
Automobile Loan | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	202,923
Automobile Loan | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	96,355
Automobile Loan | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	45,218
Automobile Loan | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,285
Automobile Loan | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,726
Automobile Loan | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	12,360
Consumer Credit Cards | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Consumer Credit Cards | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	12,360
Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	90,655
Other consumer loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	7,814
Other consumer loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,464
Other consumer loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	10,752
Other consumer loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,965
Other consumer loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	711
Other consumer loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	6,383
Other consumer loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	48,566
Pass [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,477,312
Pass [Member] | Time and demand loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	597,405
Pass [Member] | Time and demand loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	189,834
Pass [Member] | Time and demand loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	140,473
Pass [Member] | Time and demand loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	63,137
Pass [Member] | Time and demand loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	68,007
Pass [Member] | Time and demand loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	65,418
Pass [Member] | Time and demand loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	353,038
Pass [Member] | Commercial credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,604
Pass [Member] | Commercial credit cards | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Commercial credit cards | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Commercial credit cards | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Commercial credit cards | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Commercial credit cards | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Commercial credit cards | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Commercial credit cards | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,604
Pass [Member] | Real Estate Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	426,663
Pass [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	150,493
Pass [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	133,195
Pass [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	104,167
Pass [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	34,803
Pass [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	389
Pass [Member] | Real Estate Construction | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	709
Pass [Member] | Real Estate Construction | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	2,907
Pass [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,138,409
Pass [Member] | Senior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	316,028
Pass [Member] | Senior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	184,533
Pass [Member] | Senior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	142,467
Pass [Member] | Senior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	110,260
Pass [Member] | Senior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	91,059
Pass [Member] | Senior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	292,158
Pass [Member] | Senior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,904
Pass [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	602,583
Pass [Member] | Junior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,055
Pass [Member] | Junior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	5,698
Pass [Member] | Junior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,545
Pass [Member] | Junior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	2,005
Pass [Member] | Junior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,303
Pass [Member] | Junior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	6,909
Pass [Member] | Junior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	579,068
Pass [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	369,883
Pass [Member] | Multifamily | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	76,249
Pass [Member] | Multifamily | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	16,287
Pass [Member] | Multifamily | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	69,439
Pass [Member] | Multifamily | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	66,963
Pass [Member] | Multifamily | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	34,383
Pass [Member] | Multifamily | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	104,972
Pass [Member] | Multifamily | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,590
Pass [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,216,252
Pass [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	105,861
Pass [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	190,301
Pass [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	139,643
Pass [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	181,659
Pass [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	175,148
Pass [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	419,900
Pass [Member] | Nonowner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,740
Pass [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	397,123
Pass [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	58,551
Pass [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	70,726
Pass [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	55,478
Pass [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	39,351
Pass [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	26,359
Pass [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	141,376
Pass [Member] | Owner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	5,282
Pass [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	712,539
Pass [Member] | Automobile Loan | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	350,293
Pass [Member] | Automobile Loan | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	202,827
Pass [Member] | Automobile Loan | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	96,336
Pass [Member] | Automobile Loan | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	45,187
Pass [Member] | Automobile Loan | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,255
Pass [Member] | Automobile Loan | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,641
Pass [Member] | Automobile Loan | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	12,360
Pass [Member] | Consumer Credit Cards | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Pass [Member] | Consumer Credit Cards | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	12,360
Pass [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	90,642
Pass [Member] | Other consumer loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	7,814
Pass [Member] | Other consumer loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,464
Pass [Member] | Other consumer loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	10,752
Pass [Member] | Other consumer loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,965
Pass [Member] | Other consumer loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	711
Pass [Member] | Other consumer loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	6,373
Pass [Member] | Other consumer loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	48,563
Special Mention [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	48,233
Special Mention [Member] | Time and demand loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	93
Special Mention [Member] | Time and demand loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,373
Special Mention [Member] | Time and demand loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	972
Special Mention [Member] | Time and demand loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	8,820
Special Mention [Member] | Time and demand loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	6,182
Special Mention [Member] | Time and demand loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	8,043
Special Mention [Member] | Time and demand loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	20,750
Special Mention [Member] | Real Estate Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	504
Special Mention [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Real Estate Construction | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	246
Special Mention [Member] | Real Estate Construction | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	258
Special Mention [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,780
Special Mention [Member] | Senior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Senior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Senior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	83
Special Mention [Member] | Senior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Senior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	100
Special Mention [Member] | Senior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,520
Special Mention [Member] | Senior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	77
Special Mention [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	122
Special Mention [Member] | Junior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Junior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Junior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Junior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Junior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Junior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	112
Special Mention [Member] | Junior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	10
Special Mention [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	131
Special Mention [Member] | Multifamily | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Multifamily | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Multifamily | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Multifamily | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Multifamily | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Multifamily | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	131
Special Mention [Member] | Multifamily | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	161,336
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	8,979
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	21,375
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	26,339
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	37,762
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	66,752
Special Mention [Member] | Nonowner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	129
Special Mention [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	14,528
Special Mention [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	968
Special Mention [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	684
Special Mention [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,736
Special Mention [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,421
Special Mention [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	114
Special Mention [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	6,572
Special Mention [Member] | Owner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	33
Substandard [Member] | Time and demand loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	15,837
Substandard [Member] | Time and demand loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	555
Substandard [Member] | Time and demand loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	394
Substandard [Member] | Time and demand loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	779
Substandard [Member] | Time and demand loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	320
Substandard [Member] | Time and demand loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	39
Substandard [Member] | Time and demand loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	9,852
Substandard [Member] | Time and demand loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,898
Substandard [Member] | Real Estate Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	54
Substandard [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Real Estate Construction | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Real Estate Construction | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	54
Substandard [Member] | Real Estate Construction | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Senior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,134
Substandard [Member] | Senior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	24
Substandard [Member] | Senior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	17
Substandard [Member] | Senior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	273
Substandard [Member] | Senior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	105
Substandard [Member] | Senior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	336
Substandard [Member] | Senior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,379
Substandard [Member] | Senior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Junior Lien
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,564
Substandard [Member] | Junior Lien | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Junior Lien | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	85
Substandard [Member] | Junior Lien | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Junior Lien | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Junior Lien | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Junior Lien | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	106
Substandard [Member] | Junior Lien | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	3,373
Substandard [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,225
Substandard [Member] | Multifamily | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Multifamily | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Multifamily | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Multifamily | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Multifamily | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Multifamily | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	1,225
Substandard [Member] | Multifamily | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Nonowner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	43,563
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	6,917
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,973
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	31,400
Substandard [Member] | Nonowner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	273
Substandard [Member] | Owner Occupied Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	7,528
Substandard [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	903
Substandard [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	865
Substandard [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	24
Substandard [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	942
Substandard [Member] | Owner Occupied Commercial Real Estate | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	4,607
Substandard [Member] | Owner Occupied Commercial Real Estate | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	187
Substandard [Member] | Automobile Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	261
Substandard [Member] | Automobile Loan | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Automobile Loan | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	96
Substandard [Member] | Automobile Loan | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	19
Substandard [Member] | Automobile Loan | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	31
Substandard [Member] | Automobile Loan | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	30
Substandard [Member] | Automobile Loan | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	85
Substandard [Member] | Automobile Loan | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	13
Substandard [Member] | Other consumer loans | Term Loan Receivable, Originated in 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Other consumer loans | Term Loan Receivable, Originated in 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Other consumer loans | Term Loan Receivable, Originated in 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Other consumer loans | Term Loan Receivable, Originated in 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Other consumer loans | Term Loan Receivable, Originated in 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	0
Substandard [Member] | Other consumer loans | Term Loan Receivable, Originated Prior
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	10
Substandard [Member] | Other consumer loans | Revolving Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit loss	$ 3

Loans and Allowance for Credi_6

Loans and Allowance for Credit Losses - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2020USD ($)ContractnumberOfLoans	Dec. 31, 2019USD ($)Contract	Dec. 31, 2018USD ($)Contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due	90 days
Loans Receivable Held-for-sale, Amount	$ 33,436,000	$ 15,989,000
Provision for credit losses	53,472,000
Charge-offs	19,250,000	$ 12,300,000
Recorded Investment	$ 54,053,000
Number of loans modified | Contract	41	38	58
Total amount of loan modified	$ 13,969,000	$ 1,928,000	$ 8,829,000
Total gains or losses included in earnings	0	198,000
Loans with modification to rate and payment due to amortization	$ 800,000	800,000	300,000
Minimum days required for conversion of trouble debt to be in default	90 days
Unearned Deferred (Fees) Costs on Loans	$ 6,000,000	2,800,000
Unearned Premiums	(7,000,000)	(8,500,000)
Loans	6,761,183,000	6,189,148,000	5,774,139,000
Loans and Leases Receivable, Gross	$ 6,761,183,000
Forecasted Value, National Unemployment, Percent	6.68%
Weighted Average [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent	7.25%
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Forecasted Value, National Unemployment, Percent	7.48%
Total Deferrals Granted
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Number of Contracts | numberOfLoans	6,800
Loans and Leases Receivable, Gross	$ 1,400,000,000
Total Deferrals Still in Forbearance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	113,800,000
Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded commitments related to nonperforming loans	$ 200,000	1,700,000
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due	150 days
Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans Receivable Held-for-sale, Amount	$ 13,000	0
Gain (loss) on sale of impaired loans	0	400,000	$ 1,800,000
SEC Schedule, 12-09, Reserve, Off-balance Sheet Activity [Member] | Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Off balance sheet reserve to nonperforming loans	26,000	12,000
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,555,986,000	$ 1,241,853,000
Loans and Leases Receivable, Gross	1,555,986,000
Commercial Loan [Member] | Payroll Protection Program Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 478,900,000

Loans and Allowance for Credi_7

Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans by Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	$ 6,703,481
Loans	6,761,183	$ 6,189,148	$ 5,774,139
Financing Receivable, Past Due	57,702
Loans and Leases Receivable, Gross	6,761,183
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	811,180
Loans	815,815	699,375
Financing Receivable, Past Due	4,635
Loans and Leases Receivable, Gross	815,815
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,552,349
Loans	1,555,986	1,241,853
Financing Receivable, Past Due	3,637
Loans and Leases Receivable, Gross	1,555,986
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	426,231
Loans	427,221	449,039
Financing Receivable, Past Due	990
Loans and Leases Receivable, Gross	427,221
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,737,624
Loans	1,750,592	1,681,362
Financing Receivable, Past Due	12,968
Loans and Leases Receivable, Gross	1,750,592
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	2,176,097
Loans	2,211,569	2,117,519
Financing Receivable, Past Due	35,472
Loans and Leases Receivable, Gross	2,211,569
Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,537,917
Loans	1,541,382
Financing Receivable, Past Due	3,465
Loans and Leases Receivable, Gross	1,541,382
Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	14,432
Loans	14,604
Financing Receivable, Past Due	172
Loans and Leases Receivable, Gross	14,604
Senior Lien | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,144,323
Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,138,132
Financing Receivable, Past Due	6,191
Loans and Leases Receivable, Gross	1,144,323
Junior Lien | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	606,269
Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	599,492
Financing Receivable, Past Due	6,777
Loans and Leases Receivable, Gross	606,269
Multifamily | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	371,239
Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	370,779
Financing Receivable, Past Due	460
Loans and Leases Receivable, Gross	371,239
Nonowner Occupied Commercial Real Estate | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,421,151
Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	1,389,207
Financing Receivable, Past Due	31,944
Loans and Leases Receivable, Gross	1,421,151
Owner Occupied Commercial Real Estate | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	419,179
Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	416,111
Financing Receivable, Past Due	3,068
Loans and Leases Receivable, Gross	419,179
Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	709,938
Financing Receivable, Past Due	2,862
Loans and Leases Receivable, Gross	712,800
Automobile Loan | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	712,800
Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	12,146
Financing Receivable, Past Due	214
Loans and Leases Receivable, Gross	12,360
Consumer Credit Cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	12,360
Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current	89,096
Financing Receivable, Past Due	1,559
Loans and Leases Receivable, Gross	90,655
Other consumer loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	90,655
Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		699,375	590,739
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		449,039	358,978
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,241,853	1,138,473
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,681,362	1,562,405
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,117,519	$ 2,123,544
Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	8,072
Financial Asset, 30 to 59 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,870
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	146
Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	936
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,883
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	237
Financial Asset, 30 to 59 Days Past Due [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	97
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	49
Financial Asset, 30 to 59 Days Past Due [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	1,775
Financial Asset, 30 to 59 Days Past Due [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,108
Financial Asset, 30 to 59 Days Past Due [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, 30 to 59 Days Past Due [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	18
Financial Asset, 30 to 59 Days Past Due [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	219
Financial Asset, 30 to 59 Days Past Due [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,090
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	52
Financial Asset, 30 to 59 Days Past Due [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	728
Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,566
Financial Asset, 60 to 89 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	852
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	62
Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	1,492
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	160
Financial Asset, 60 to 89 Days Past Due [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	28
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	34
Financial Asset, 60 to 89 Days Past Due [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	660
Financial Asset, 60 to 89 Days Past Due [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	832
Financial Asset, 60 to 89 Days Past Due [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, 60 to 89 Days Past Due [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	104
Financial Asset, 60 to 89 Days Past Due [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	56
Financial Asset, 60 to 89 Days Past Due [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	417
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	39
Financial Asset, 60 to 89 Days Past Due [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	396
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	1,523
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	639
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	112
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	769
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	23
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	89
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	267
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	502
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	94
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	123
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	422
Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	45,541
Nonaccrual Commercial Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	274
Nonaccrual Commercial Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,317
Nonaccrual Commercial Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	54
Nonaccrual Commercial Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	6,824
Nonaccrual Commercial Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	35,072
Nonaccrual Commercial Loans [Member] | Time and demand loans | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,317
Nonaccrual Commercial Loans [Member] | Commercial credit cards | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Nonaccrual Commercial Loans [Member] | Senior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,489
Nonaccrual Commercial Loans [Member] | Junior Lien | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	3,335
Nonaccrual Commercial Loans [Member] | Multifamily | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	460
Nonaccrual Commercial Loans [Member] | Nonowner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	31,822
Nonaccrual Commercial Loans [Member] | Owner Occupied Commercial Real Estate | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	2,790
Nonaccrual Commercial Loans [Member] | Automobile Loan | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	261
Nonaccrual Commercial Loans [Member] | Consumer Credit Cards | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	0
Nonaccrual Commercial Loans [Member] | Other consumer loans | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	$ 13
Originated Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		34,741
Current		5,679,632
Loans		5,714,373
Loans and Leases Receivable, Gross		5,714,373
Originated Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		685,416
Loans and Leases Receivable, Gross		685,416
Originated Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,212,026
Loans and Leases Receivable, Gross		1,212,026
Originated Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		442,777
Loans and Leases Receivable, Gross		442,777
Originated Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,415,808
Loans and Leases Receivable, Gross		1,415,808
Originated Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,958,346
Loans and Leases Receivable, Gross		1,958,346
Originated Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		6,328
Current		679,088
Loans		685,416
Originated Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		207
Current		442,570
Loans		442,777
Originated Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		9,368
Current		1,202,658
Loans		1,212,026
Originated Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		11,888
Current		1,403,920
Loans		1,415,808
Originated Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		6,950
Current		1,951,396
Loans		1,958,346
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		8,643
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		4,070
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		198
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		391
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		3,757
Originated Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		227
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,940
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,020
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		57
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		749
Originated Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		114
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,816
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		931
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		9
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		140
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		736
Originated Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Originated Loans [Member] | Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		22,342
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		307
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		8,780
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		6,646
Originated Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		6,609
Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		3,385
Current		471,390
Loans		474,775
Loans and Leases Receivable, Gross		474,775
Acquired Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		13,959
Loans and Leases Receivable, Gross		13,959
Acquired Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		29,827
Loans and Leases Receivable, Gross		29,827
Acquired Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		6,262
Loans and Leases Receivable, Gross		6,262
Acquired Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		265,554
Loans and Leases Receivable, Gross		265,554
Acquired Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		159,173
Loans and Leases Receivable, Gross		159,173
Acquired Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		223
Current		13,736
Loans		13,959
Acquired Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		0
Current		6,262
Loans		6,262
Acquired Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		76
Current		29,751
Loans		29,827
Acquired Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		2,681
Current		262,873
Loans		265,554
Acquired Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual		405
Current		158,768
Loans		159,173
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		392
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		87
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		304
Acquired Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		403
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		89
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		207
Acquired Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		107
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		257
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		35
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		221
Acquired Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		2,333
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Loans To Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		12
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		0
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		74
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		1,949
Acquired Loans [Member] | Nonaccrual Commercial Loans [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due		$ 298

Loans and Allowance for Credi_8

Loans and Allowance for Credit Losses - Recorded Investment and Unpaid Principal Balance for Impaired Loans with Associated Allowance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 54,053
Unpaid Principal Balance	65,331
Related Allowance	4,906
Average Recorded Investment	50,728
Interest Income Recognized	639
Commercial Financial Agricultural And Other With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,025
Unpaid Principal Balance	2,725
Average Recorded Investment	6,371
Interest Income Recognized	80
Commercial Financial Agricultural And Other With No Related Allowance [Member] | Time and demand loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	2,025
Unpaid Principal Balance	2,725
Average Recorded Investment	6,371
Interest Income Recognized	80
Real Estate Construction With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	54
Unpaid Principal Balance	53
Average Recorded Investment	146
Interest Income Recognized	14
Residential real estate with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	10,939
Unpaid Principal Balance	13,258
Average Recorded Investment	11,913
Interest Income Recognized	335
Residential real estate with no related allowance recorded [Member] | Senior Lien
Financing Receivable, Impaired [Line Items]
Recorded Investment	6,062
Unpaid Principal Balance	7,575
Average Recorded Investment	6,605
Interest Income Recognized	241
Residential real estate with no related allowance recorded [Member] | Junior Lien
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,877
Unpaid Principal Balance	5,683
Average Recorded Investment	5,308
Interest Income Recognized	94
Commercial Real Estate With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	20,650
Unpaid Principal Balance	23,641
Average Recorded Investment	22,287
Interest Income Recognized	184
Commercial Real Estate With No Related Allowance [Member] | Multifamily
Financing Receivable, Impaired [Line Items]
Recorded Investment	1
Unpaid Principal Balance	82
Average Recorded Investment	1
Interest Income Recognized	0
Commercial Real Estate With No Related Allowance [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment	16,786
Unpaid Principal Balance	19,459
Average Recorded Investment	18,536
Interest Income Recognized	82
Commercial Real Estate With No Related Allowance [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment	3,863
Unpaid Principal Balance	4,100
Average Recorded Investment	3,750
Interest Income Recognized	102
Loans To Individuals With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	418
Unpaid Principal Balance	447
Average Recorded Investment	470
Interest Income Recognized	13
Loans To Individuals With No Related Allowance [Member] | Automobiles
Financing Receivable, Impaired [Line Items]
Recorded Investment	405
Unpaid Principal Balance	430
Average Recorded Investment	447
Interest Income Recognized	13
Loans To Individuals With No Related Allowance [Member] | Other consumer loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	13
Unpaid Principal Balance	17
Average Recorded Investment	23
Interest Income Recognized	0
Subtotal with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	34,086
Unpaid Principal Balance	40,124
Average Recorded Investment	41,187
Interest Income Recognized	626
Commercial, financial, agricultural and other With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,210
Unpaid Principal Balance	9,377
Related Allowance	1,268
Average Recorded Investment	1,544
Interest Income Recognized	3
Commercial, financial, agricultural and other With an allowance recorded [Member] | Time and demand loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,210
Unpaid Principal Balance	9,377
Related Allowance	1,268
Average Recorded Investment	1,544
Interest Income Recognized	3
Real estate construction with an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Residential real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Residential real estate With an allowance recorded [Member] | Senior Lien
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Residential real estate With an allowance recorded [Member] | Junior Lien
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Commercial real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	15,757
Unpaid Principal Balance	15,830
Related Allowance	3,638
Average Recorded Investment	7,997
Interest Income Recognized	10
Commercial real estate With an allowance recorded [Member] | Multifamily
Financing Receivable, Impaired [Line Items]
Recorded Investment	459
Unpaid Principal Balance	470
Related Allowance	116
Average Recorded Investment	395
Interest Income Recognized	0
Commercial real estate With an allowance recorded [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment	15,060
Unpaid Principal Balance	15,122
Related Allowance	3,508
Average Recorded Investment	7,363
Interest Income Recognized	0
Commercial real estate With an allowance recorded [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Recorded Investment	238
Unpaid Principal Balance	238
Related Allowance	14
Average Recorded Investment	239
Interest Income Recognized	10
Loans to individuals With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Loans to individuals With an allowance recorded [Member] | Automobiles
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Loans to individuals With an allowance recorded [Member] | Other consumer loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	0
Unpaid Principal Balance	0
Related Allowance	0
Average Recorded Investment	0
Interest Income Recognized	0
Subtotal With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	19,967
Unpaid Principal Balance	25,207
Related Allowance	4,906
Average Recorded Investment	9,541
Interest Income Recognized	$ 13
Originated Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		$ 29,698
Unpaid Principal Balance		39,122
Related Allowance		2,432
Average Recorded Investment		27,154	$ 41,386
Interest Income Recognized		684	1,098
Originated Loans [Member] | Commercial Financial Agricultural And Other With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		1,848
Unpaid Principal Balance		6,997
Average Recorded Investment		2,411	18,480
Interest Income Recognized		66	602
Originated Loans [Member] | Real Estate Construction With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Originated Loans [Member] | Residential real estate with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		10,372
Unpaid Principal Balance		12,437
Average Recorded Investment		10,819	10,651
Interest Income Recognized		365	271
Originated Loans [Member] | Commercial Real Estate With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		3,015
Unpaid Principal Balance		3,210
Average Recorded Investment		7,455	7,919
Interest Income Recognized		156	177
Originated Loans [Member] | Loans To Individuals With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		406
Unpaid Principal Balance		640
Average Recorded Investment		371	310
Interest Income Recognized		17	11
Originated Loans [Member] | Subtotal with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		15,641
Unpaid Principal Balance		23,284
Average Recorded Investment		21,056	37,360
Interest Income Recognized		604	1,061
Originated Loans [Member] | Commercial, financial, agricultural and other With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		8,290
Unpaid Principal Balance		10,032
Related Allowance		1,580
Average Recorded Investment		4,110	2,531
Interest Income Recognized		77	20
Originated Loans [Member] | Real estate construction with an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Originated Loans [Member] | Residential real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		474
Unpaid Principal Balance		498
Related Allowance		1
Average Recorded Investment		241	504
Interest Income Recognized		0	13
Originated Loans [Member] | Commercial real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		5,293
Unpaid Principal Balance		5,308
Related Allowance		851
Average Recorded Investment		1,747	991
Interest Income Recognized		3	4
Originated Loans [Member] | Loans to individuals With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Originated Loans [Member] | Subtotal With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		14,057
Unpaid Principal Balance		15,838
Related Allowance		2,432
Average Recorded Investment		6,098	4,026
Interest Income Recognized		80	37
Acquired Loans [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		2,519
Unpaid Principal Balance		2,993
Related Allowance		0
Average Recorded Investment		5,225	3,712
Interest Income Recognized		26	15
Acquired Loans [Member] | Commercial Financial Agricultural And Other With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		73
Unpaid Principal Balance		73
Average Recorded Investment		2,479	214
Interest Income Recognized		0	10
Acquired Loans [Member] | Real Estate Construction With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Acquired Loans [Member] | Residential real estate with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		2,136
Unpaid Principal Balance		2,585
Average Recorded Investment		1,986	1,906
Interest Income Recognized		8	5
Acquired Loans [Member] | Commercial Real Estate With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		298
Unpaid Principal Balance		320
Average Recorded Investment		747	1,565
Interest Income Recognized		18	0
Acquired Loans [Member] | Loans To Individuals With No Related Allowance [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		12
Unpaid Principal Balance		15
Average Recorded Investment		13	16
Interest Income Recognized		0	0
Acquired Loans [Member] | Subtotal with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		2,519
Unpaid Principal Balance		2,993
Average Recorded Investment		5,225	3,701
Interest Income Recognized		26	15
Acquired Loans [Member] | Commercial, financial, agricultural and other With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	11
Interest Income Recognized		0	0
Acquired Loans [Member] | Real estate construction with an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Acquired Loans [Member] | Residential real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Acquired Loans [Member] | Commercial real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Acquired Loans [Member] | Loans to individuals With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	0
Interest Income Recognized		0	0
Acquired Loans [Member] | Subtotal With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment		0
Unpaid Principal Balance		0
Related Allowance		0
Average Recorded Investment		0	11
Interest Income Recognized		$ 0	$ 0

Loans and Allowance for Credi_9

Loans and Allowance for Credit Losses - Troubled Debt Restructured Loans and Commitments (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loans and Leases Receivable Disclosure [Abstract]
Accrual status	$ 8,512	$ 7,542	$ 8,757
Nonaccrual status	14,740	6,037	11,761
Total	23,252	13,579	20,518
Letters of Credit Outstanding, Amount	60	60	60
Unused lines of credit	11	163	1,027
Commitments Net	$ 71	$ 223	$ 1,087

Loans and Allowance for Cred_10

Loans and Allowance for Credit Losses - Troubled Debt Restructurings Identified During Period (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Contract	Dec. 31, 2019USD ($)Contract	Dec. 31, 2018USD ($)Contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	41	38	58
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 14,874	$ 8,302	$ 11,281
Financing Receivable, Troubled Debt Restructuring	13,969	1,928	8,829
Financing Receivable Troubled Debt Restructuring Specific Reserve	636	0	0
Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	14,098	7,525	10,635
Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	776	760	330
Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0	$ 17	$ 316
Commercial Loan [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	4	2	3
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 2,805	$ 156	$ 8,324
Financing Receivable, Troubled Debt Restructuring	2,196	154	6,104
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 636	0	0
Commercial Loan [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	4
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 2,805
Financing Receivable, Troubled Debt Restructuring	2,196
Financing Receivable Troubled Debt Restructuring Specific Reserve	636
Commercial Loan [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	2,176	156	8,250
Commercial Loan [Member] | Contractual Payment Modification [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	2,176
Commercial Loan [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	629	0	0
Commercial Loan [Member] | Contractual Interest Rate Reduction [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	629
Commercial Loan [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0	$ 0	$ 74
Commercial Loan [Member] | Extended Maturity [Member] | Time and demand loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0
Residential Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	18	20	37
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 950	$ 1,186	$ 1,799
Financing Receivable, Troubled Debt Restructuring	791	1,059	1,638
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 0	0	0
Residential Real Estate [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	9
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 546
Financing Receivable, Troubled Debt Restructuring	411
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 0
Residential Real Estate [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	9
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 404
Financing Receivable, Troubled Debt Restructuring	380
Financing Receivable Troubled Debt Restructuring Specific Reserve	0
Residential Real Estate [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	917	965	1,316
Residential Real Estate [Member] | Contractual Payment Modification [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	513
Residential Real Estate [Member] | Contractual Payment Modification [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	404
Residential Real Estate [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	33	204	241
Residential Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	33
Residential Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0
Residential Real Estate [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0	$ 17	$ 242
Residential Real Estate [Member] | Extended Maturity [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0
Residential Real Estate [Member] | Extended Maturity [Member] | Junior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0
Commercial Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	5	5	3
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 10,857	$ 6,817	$ 1,016
Financing Receivable, Troubled Debt Restructuring	10,758	594	975
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 0	0	0
Commercial Real Estate [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	4
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 10,289
Financing Receivable, Troubled Debt Restructuring	10,263
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 0
Commercial Real Estate [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	1
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 568
Financing Receivable, Troubled Debt Restructuring	495
Financing Receivable Troubled Debt Restructuring Specific Reserve	0
Commercial Real Estate [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	10,857	6,261	1,016
Commercial Real Estate [Member] | Contractual Payment Modification [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	10,289
Commercial Real Estate [Member] | Contractual Payment Modification [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	568
Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0	556	0
Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0
Commercial Real Estate [Member] | Contractual Interest Rate Reduction [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0
Commercial Real Estate [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0	$ 0	$ 0
Commercial Real Estate [Member] | Extended Maturity [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0
Commercial Real Estate [Member] | Extended Maturity [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0
Loans To Individuals [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	14	11	15
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 262	$ 143	$ 142
Financing Receivable, Troubled Debt Restructuring	224	121	112
Financing Receivable Troubled Debt Restructuring Specific Reserve	$ 0	0	0
Loans To Individuals [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Contract	14
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 262
Financing Receivable, Troubled Debt Restructuring	224
Financing Receivable Troubled Debt Restructuring Specific Reserve	0
Loans To Individuals [Member] | Contractual Payment Modification [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	148	143	53
Loans To Individuals [Member] | Contractual Payment Modification [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	148
Loans To Individuals [Member] | Contractual Interest Rate Reduction [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	114	0	89
Loans To Individuals [Member] | Contractual Interest Rate Reduction [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	114
Loans To Individuals [Member] | Extended Maturity [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	0	$ 0	$ 0
Loans To Individuals [Member] | Extended Maturity [Member] | Automobiles
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0

Loans and Allowance for Cred_11

Loans and Allowance for Credit Losses - Restructured Loans that are Considered to be in Default (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)loan	Dec. 31, 2019USD ($)loan	Dec. 31, 2018USD ($)loan
Residential Portfolio Segment [Member] | Residential Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | loan	1	0	1
Financing Receivable, Troubled Debt Restructuring, Subsequent Default | $	$ 34	$ 0	$ 49
Loans To Individuals [Member] | Loans To Individuals [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | loan	2	0	0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default | $	$ 74	$ 0	$ 0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | loan	3	0	1
Financing Receivable, Troubled Debt Restructuring, Subsequent Default | $	$ 108	$ 0	$ 49
Senior Lien | Residential Real Estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | loan	1
Financing Receivable, Troubled Debt Restructuring, Subsequent Default | $	$ 34
Automobiles | Loans To Individuals [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | loan	2
Financing Receivable, Troubled Debt Restructuring, Subsequent Default | $	$ 74

Loans and Allowance for Cred_12

Loans and Allowance for Credit Losses - Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 51,637	$ 47,764
Ending Balance	101,309	51,637	$ 47,764
Ending balance: individually evaluated for impaired	4,906	2,432	1,631
Ending balance: collectively evaluated for impaired	96,403	49,205	46,133
Ending balance: individually evaluated for impaired		17,833	21,088
Ending balance: collectively evaluated for impaired		6,171,315	5,753,051
Financing receivable, before allowance for credit loss	6,761,183
Financing Receivable, Allowance for Credit Loss, Writeoff	(19,250)	(12,300)
Recoveries	2,057
Provision for credit losses	53,472
Loans	6,761,183	6,189,148	5,774,139
Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	41,463
Ending balance: collectively evaluated for impaired	6,719,720
Financing receivable, before allowance for credit loss	6,761,183
Time and demand loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	1,541,382
Commercial credit cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	14,604
Senior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	1,144,323
Junior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	606,269
Multifamily
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	371,239
Nonowner Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	1,421,151
Owner Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	419,179
Consumer Credit Cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	12,360
Other consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing receivable, before allowance for credit loss	90,655
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	13,393
Ending Balance		13,393
Commercial, financial, agricultural and other [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	20,234	19,374
Ending Balance	17,187	20,234	19,374
Ending balance: individually evaluated for impaired	1,268	1,580	928
Ending balance: collectively evaluated for impaired	15,919	18,654	18,446
Ending balance: individually evaluated for impaired		9,246	11,631
Ending balance: collectively evaluated for impaired		1,232,607	1,126,842
Financing Receivable, Allowance for Credit Loss, Writeoff	(6,318)
Recoveries	314
Provision for credit losses	1,479
Loans		1,241,853	1,138,473
Commercial, financial, agricultural and other [Member] | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	5,411
Ending balance: collectively evaluated for impaired	1,550,575
Financing receivable, before allowance for credit loss	1,555,986
Commercial, financial, agricultural and other [Member] | Time and demand loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	16,838	0
Ending balance: individually evaluated for impaired	1,268
Ending balance: collectively evaluated for impaired	15,570
Financing Receivable, Allowance for Credit Loss, Writeoff	(6,220)
Recoveries	301
Provision for credit losses	1,515
Commercial, financial, agricultural and other [Member] | Time and demand loans | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	5,411
Ending balance: collectively evaluated for impaired	1,535,971
Financing receivable, before allowance for credit loss	1,541,382
Commercial, financial, agricultural and other [Member] | Commercial credit cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	349	0
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	349
Financing Receivable, Allowance for Credit Loss, Writeoff	(98)
Recoveries	13
Provision for credit losses	(36)
Commercial, financial, agricultural and other [Member] | Commercial credit cards | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	14,604
Financing receivable, before allowance for credit loss	14,604
Commercial, financial, agricultural and other [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	1,478
Ending Balance		1,478
Commercial, financial, agricultural and other [Member] | Cumulative Effect, Period of Adoption, Adjustment | Time and demand loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	21,242
Ending Balance		21,242
Commercial, financial, agricultural and other [Member] | Cumulative Effect, Period of Adoption, Adjustment | Commercial credit cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	470
Ending Balance		470
Real Estate Construction [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	2,558	2,002
Ending Balance	7,966	2,558	2,002
Ending balance: individually evaluated for impaired	0	0	0
Ending balance: collectively evaluated for impaired	7,966	2,558	2,002
Ending balance: individually evaluated for impaired		0	0
Ending balance: collectively evaluated for impaired		449,039	358,978
Financing Receivable, Allowance for Credit Loss, Writeoff	0
Recoveries	26
Provision for credit losses	4,820
Loans		449,039	358,978
Real Estate Construction [Member] | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	427,221
Financing receivable, before allowance for credit loss	427,221
Real Estate Construction [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	562
Ending Balance		562
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	19,768	18,386
Ending Balance	41,953	19,768	18,386
Ending balance: individually evaluated for impaired	3,638	851	596
Ending balance: collectively evaluated for impaired	38,315	18,917	17,790
Ending balance: individually evaluated for impaired		6,846	5,710
Ending balance: collectively evaluated for impaired		2,110,673	2,117,834
Financing Receivable, Allowance for Credit Loss, Writeoff	(4,939)
Recoveries	312
Provision for credit losses	27,019
Loans		2,117,519	2,123,544
Commercial real estate [Member] | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	34,947
Ending balance: collectively evaluated for impaired	2,176,622
Financing receivable, before allowance for credit loss	2,211,569
Commercial real estate [Member] | Multifamily
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	6,240	0
Ending balance: individually evaluated for impaired	116
Ending balance: collectively evaluated for impaired	6,124
Financing Receivable, Allowance for Credit Loss, Writeoff	0
Recoveries	0
Provision for credit losses	4,593
Commercial real estate [Member] | Multifamily | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	459
Ending balance: collectively evaluated for impaired	370,780
Financing receivable, before allowance for credit loss	371,239
Commercial real estate [Member] | Nonowner Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	28,414	0
Ending balance: individually evaluated for impaired	3,508
Ending balance: collectively evaluated for impaired	24,906
Financing Receivable, Allowance for Credit Loss, Writeoff	(4,678)
Recoveries	187
Provision for credit losses	20,588
Commercial real estate [Member] | Nonowner Occupied Commercial Real Estate | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	31,450
Ending balance: collectively evaluated for impaired	1,389,701
Financing receivable, before allowance for credit loss	1,421,151
Commercial real estate [Member] | Owner Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	7,299	0
Ending balance: individually evaluated for impaired	14
Ending balance: collectively evaluated for impaired	7,285
Financing Receivable, Allowance for Credit Loss, Writeoff	(261)
Recoveries	125
Provision for credit losses	1,838
Commercial real estate [Member] | Owner Occupied Commercial Real Estate | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	3,038
Ending balance: collectively evaluated for impaired	416,141
Financing receivable, before allowance for credit loss	419,179
Commercial real estate [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	(207)
Ending Balance		(207)
Commercial real estate [Member] | Cumulative Effect, Period of Adoption, Adjustment | Multifamily
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	1,647
Ending Balance		1,647
Commercial real estate [Member] | Cumulative Effect, Period of Adoption, Adjustment | Nonowner Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	12,317
Ending Balance		12,317
Commercial real estate [Member] | Cumulative Effect, Period of Adoption, Adjustment | Owner Occupied Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	5,597
Ending Balance		5,597
Loans To Individuals [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,984	4,033
Ending Balance	19,845	4,984	4,033
Ending balance: individually evaluated for impaired	0	0	0
Ending balance: collectively evaluated for impaired	19,845	4,984	4,033
Ending balance: individually evaluated for impaired		0	0
Ending balance: collectively evaluated for impaired		699,375	590,739
Financing Receivable, Allowance for Credit Loss, Writeoff	(6,953)
Recoveries	991
Provision for credit losses	16,539
Loans		699,375	590,739
Loans To Individuals [Member] | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	815,815
Financing receivable, before allowance for credit loss	815,815
Loans To Individuals [Member] | Automobiles
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	16,133	0
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	16,133
Financing Receivable, Allowance for Credit Loss, Writeoff	(3,954)
Recoveries	745
Provision for credit losses	13,236
Loans To Individuals [Member] | Automobiles | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	712,800
Financing receivable, before allowance for credit loss	712,800
Loans To Individuals [Member] | Consumer Credit Cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	635	0
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	635
Financing Receivable, Allowance for Credit Loss, Writeoff	(595)
Recoveries	36
Provision for credit losses	973
Loans To Individuals [Member] | Consumer Credit Cards | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	12,360
Financing receivable, before allowance for credit loss	12,360
Loans To Individuals [Member] | Other consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	3,077	0
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	3,077
Financing Receivable, Allowance for Credit Loss, Writeoff	(2,404)
Recoveries	210
Provision for credit losses	2,330
Loans To Individuals [Member] | Other consumer loans | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	90,655
Financing receivable, before allowance for credit loss	90,655
Loans To Individuals [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,284
Ending Balance		4,284
Loans To Individuals [Member] | Cumulative Effect, Period of Adoption, Adjustment | Automobiles
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	6,106
Ending Balance		6,106
Loans To Individuals [Member] | Cumulative Effect, Period of Adoption, Adjustment | Consumer Credit Cards
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	221
Ending Balance		221
Loans To Individuals [Member] | Cumulative Effect, Period of Adoption, Adjustment | Other consumer loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	2,941
Ending Balance		2,941
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,093	3,969
Ending Balance	14,358	4,093	3,969
Ending balance: individually evaluated for impaired	0	1	107
Ending balance: collectively evaluated for impaired	14,358	4,092	3,862
Ending balance: individually evaluated for impaired		1,741	3,747
Ending balance: collectively evaluated for impaired		1,679,621	1,558,658
Financing Receivable, Allowance for Credit Loss, Writeoff	(1,040)
Recoveries	414
Provision for credit losses	3,615
Loans		1,681,362	1,562,405
Residential Real Estate [Member] | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	1,105
Ending balance: collectively evaluated for impaired	1,749,487
Financing receivable, before allowance for credit loss	1,750,592
Residential Real Estate [Member] | Senior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	7,919	0
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	7,919
Financing Receivable, Allowance for Credit Loss, Writeoff	(550)
Recoveries	296
Provision for credit losses	847
Residential Real Estate [Member] | Senior Lien | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	528
Ending balance: collectively evaluated for impaired	1,143,795
Financing receivable, before allowance for credit loss	1,144,323
Residential Real Estate [Member] | Junior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0
Ending Balance	6,439	0
Ending balance: individually evaluated for impaired	0
Ending balance: collectively evaluated for impaired	6,439
Financing Receivable, Allowance for Credit Loss, Writeoff	(490)
Recoveries	118
Provision for credit losses	2,768
Residential Real Estate [Member] | Junior Lien | Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Ending balance: individually evaluated for impaired	577
Ending balance: collectively evaluated for impaired	605,692
Financing receivable, before allowance for credit loss	606,269
Residential Real Estate [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	7,276
Ending Balance		7,276
Residential Real Estate [Member] | Cumulative Effect, Period of Adoption, Adjustment | Senior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	7,326
Ending Balance		7,326
Residential Real Estate [Member] | Cumulative Effect, Period of Adoption, Adjustment | Junior Lien
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,043
Ending Balance		4,043
Originated Loans [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	51,585	47,586	48,252
Ending Balance		51,585	47,586
Financing Receivable, Allowance for Credit Loss, Writeoff		(10,032)	(14,902)
Recoveries		1,449	1,846
Provision for credit losses		12,582	12,390
Loans		5,714,373
Originated Loans [Member] | Commercial, financial, agricultural and other [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	20,221	19,235	23,418
Ending Balance		20,221	19,235
Financing Receivable, Allowance for Credit Loss, Writeoff		(2,667)	(5,201)
Recoveries		245	746
Provision for credit losses		3,408	272
Loans		1,212,026
Originated Loans [Member] | Real Estate Construction [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	2,558	2,002	1,349
Ending Balance		2,558	2,002
Financing Receivable, Allowance for Credit Loss, Writeoff		0	0
Recoveries		158	135
Provision for credit losses		398	518
Loans		442,777
Originated Loans [Member] | Commercial real estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	19,731	18,382	17,328
Ending Balance		19,731	18,382
Financing Receivable, Allowance for Credit Loss, Writeoff		(632)	(3,930)
Recoveries		189	153
Provision for credit losses		1,792	4,831
Loans		1,958,346
Originated Loans [Member] | Loans To Individuals [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,984	4,033	3,404
Ending Balance		4,984	4,033
Financing Receivable, Allowance for Credit Loss, Writeoff		(5,747)	(4,554)
Recoveries		611	579
Provision for credit losses		6,087	4,604
Loans		685,416
Originated Loans [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,091	3,934	2,753
Ending Balance		4,091	3,934
Financing Receivable, Allowance for Credit Loss, Writeoff		(986)	(1,217)
Recoveries		246	233
Provision for credit losses		897	2,165
Loans		1,415,808
Acquired Loans [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	52	178	46
Ending Balance		52	178
Financing Receivable, Allowance for Credit Loss, Writeoff		(2,242)	(211)
Recoveries		165	202
Provision for credit losses		1,951	141
Loans		474,775
Acquired Loans [Member] | Commercial, financial, agricultural and other [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	13	139	11
Ending Balance		13	139
Financing Receivable, Allowance for Credit Loss, Writeoff		(726)	(93)
Recoveries		81	42
Provision for credit losses		519	179
Loans		29,827
Acquired Loans [Member] | Real Estate Construction [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0	0	0
Ending Balance		0	0
Financing Receivable, Allowance for Credit Loss, Writeoff		0	0
Recoveries		0	6
Provision for credit losses		0	(6)
Loans		6,262
Acquired Loans [Member] | Commercial real estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	37	4	29
Ending Balance		37	4
Financing Receivable, Allowance for Credit Loss, Writeoff		(1,376)	0
Recoveries		0	0
Provision for credit losses		1,409	(25)
Loans		159,173
Acquired Loans [Member] | Loans To Individuals [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	0	0	0
Ending Balance		0	0
Financing Receivable, Allowance for Credit Loss, Writeoff		(84)	(22)
Recoveries		15	26
Provision for credit losses		69	(4)
Loans		13,959
Acquired Loans [Member] | Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 2	35	6
Ending Balance		2	35
Financing Receivable, Allowance for Credit Loss, Writeoff		(56)	(96)
Recoveries		69	128
Provision for credit losses		(46)	$ (3)
Loans		$ 265,554

Commitments and Letters of Cr_3

Commitments and Letters of Credit - Notional Amount of Commitments and Letter of Credit Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Commitments Net	$ 71	$ 223	$ 1,087
Commitments to extend credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	2,097,628	1,981,275
Financial standby letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	15,988	16,630
Performance standby letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	16,864	23,293
Commercial letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 783	$ 783

Commitments and Letters of Cr_4

Commitments and Letters of Credit - Additional Information (Detail) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Notional amount of financial standby letters of credit	$ 2,600,000
Notional amount of performance standby letters of credit	300,000
Notional amount of commercial letters of credit	0
Financial instrument of credit risk	104,000	$ 138,000
Unused commitments and letters of credit [Member]
Loss Contingencies [Line Items]
Commitment liability	$ 7,400,000	$ 4,500,000

Premises and Equipment - Schedu

Premises and Equipment - Schedule of Premises and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 291,264	$ 294,188
Less accumulated depreciation and amortization	165,747	156,920
Total premises and equipment	125,517	137,268
Land [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	15,441	15,446
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 77,003	76,965
Buildings and improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Buildings and improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	50 years
Property Subject to Operating Lease [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 48,642	52,114
Property Subject to Operating Lease [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	1 year
Property Subject to Operating Lease [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	25 years
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 35,347	37,716
Leasehold improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Leasehold improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	40 years
Furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 73,150	71,548
Furniture and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Furniture and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Software [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 41,681	$ 40,399
Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Operating Lease, Right-of-Use Asset	$ 42,617	$ 48,642
Operating Lease, Liability	46,819	52,894
Premises and equipment, available-for-sale	2,600
Operating Leases, Rent Expense, Contingent Rentals	6,700	4,900	$ 4,100
Gain (Loss) on Termination of Lease	700
Assets
Property, Plant and Equipment [Line Items]
Gain (Loss) on Contract Termination	3,800
Liability
Property, Plant and Equipment [Line Items]
Gain (Loss) on Contract Termination	3,600
Premises and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation included in noninterest expense	10,900	10,500	$ 9,500
Property Subject to Operating Lease [Member]
Property, Plant and Equipment [Line Items]
Depreciation included in noninterest expense	2,600	$ 3,500
Accounting Standards Update 2016-02 [Member]
Property, Plant and Equipment [Line Items]
Operating Lease, Right-of-Use Asset	38,500
Operating Lease, Liability	$ 41,800

Premises and Equipment Operatin

Premises and Equipment Operating Lease Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lease Expense and Cash Flows [Abstract]
Operating Lease, Right-of-Use Asset	$ 42,617	$ 48,642
Operating Lease, Liability	46,819	52,894
Operating Lease, Cost	$ 5,930	$ 5,328
Operating Lease, Weighted Average Remaining Lease Term	14 years 9 months 29 days	15 years 3 months 7 days
Operating Lease, Weighted Average Discount Rate, Percent	3.42%	3.43%
Operating Leases, Rent Expense, Contingent Rentals	$ 5,979	$ 4,656

Premises and Equipment Schedule

Premises and Equipment Schedule of Lease Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 4,765
Operating Leases, Future Minimum Payments, Due in Two Years	4,653
Operating Leases, Future Minimum Payments, Due in Three Years	4,533
Operating Leases, Future Minimum Payments, Due in Four Years	4,399
Operating Leases, Future Minimum Payments, Due in Five Years	4,174
Operating Leases, Future Minimum Payments, Due Thereafter	38,325
Operating Leases, Future Minimum Payments Due	60,849
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	14,030
Operating Lease, Liability	$ 46,819	$ 52,894

Goodwill and Other Amortizing_3

Goodwill and Other Amortizing Intangible Assets - Additional Information (Detail) - USD ($)	Sep. 06, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Other Intangibles [Line Items]
Goodwill		$ 303,328,000	$ 303,328,000
Impairment charges on goodwill		0	0	$ 0
Servicing Asset		1,900,000	1,300,000
Total amortization		13,223,000	13,100,000
Intangible amortization		3,689,000	3,344,000	3,217,000
Servicing Asset at Amortized Cost, Amortization		$ 300,000	200,000
Customer deposit intangibles
Goodwill And Other Intangibles [Line Items]
Core deposits remaining amortization period		8 years 8 months 12 days
Core deposits weighted average amortization period		7 years 1 month 6 days
Total amortization		$ 11,653,000	11,760,000
Customer list intangible
Goodwill And Other Intangibles [Line Items]
Core deposits remaining amortization period		8 years 8 months 12 days
Core deposits weighted average amortization period		6 years 9 months 18 days
Total amortization		$ 1,570,000	1,340,000
Customer-Related Intangible Assets [Member]
Goodwill And Other Intangibles [Line Items]
Intangible amortization		$ 3,400,000	$ 3,200,000	$ 3,100,000
Santander Bank, N.A. [Member]
Goodwill And Other Intangibles [Line Items]
Goodwill, Acquired During Period	$ 29,126,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 5,615,000

Goodwill and Other Amortizing_4

Goodwill and Other Amortizing Intangible Assets - Summarized Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 24,856	$ 28,126
Accumulated Amortization	(13,223)	(13,100)
Net Intangible Assets	11,633	15,026
Customer deposit intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	22,573	25,843
Accumulated Amortization	(11,653)	(11,760)
Net Intangible Assets	10,920	14,083
Customer list intangible
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	2,283	2,283
Accumulated Amortization	(1,570)	(1,340)
Net Intangible Assets	$ 713	$ 943

Goodwill and Other Amortizing_5

Goodwill and Other Amortizing Intangible Assets - Estimated Amortization Expense of Core Deposit Intangibles (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Goodwill And Other Intangibles [Line Items]
2016	$ 2,946
2017	2,502
2018	2,060
2019	1,619
2020	1,181
Thereafter	1,325
Net Intangible Assets	11,633	$ 15,026
Customer list intangible
Goodwill And Other Intangibles [Line Items]
2016	193
2017	159
2018	127
2019	97
2020	69
Thereafter	68
Net Intangible Assets	713	943
Customer deposit intangibles
Goodwill And Other Intangibles [Line Items]
2016	2,753
2017	2,343
2018	1,933
2019	1,522
2020	1,112
Thereafter	1,257
Net Intangible Assets	$ 10,920	$ 14,083

Interest-Bearing Deposits - Com

Interest-Bearing Deposits - Components of Interest-Bearing Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits [Abstract]
Interest-bearing demand deposits	$ 250,353	$ 254,981
Savings deposits	4,305,391	3,896,536
Time deposits	562,964	835,851
Total interest-bearing deposits	$ 5,118,708	$ 4,987,368

Interest-Bearing Deposits - Add

Interest-Bearing Deposits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Interest-bearing demand deposit, money market	$ 1,200	$ 1,100
Certificates of deposit in denominations of $100 thousand or more	93.1	143.9
Interest expense related to certificates of deposit $100 thousand or greater	2	3.3	$ 1.6
Deposit Liabilities Reclassified as Loans Receivable	$ 0.7	$ 0.9

Interest-Bearing Deposits - Sch

Interest-Bearing Deposits - Scheduled Maturities of Time Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits [Abstract]
2017	$ 419,197
2018	88,783
2019	22,997
2020	16,222
2021 and thereafter	15,765
Total	$ 562,964	$ 835,851

Short-term Borrowings - Summary

Short-term Borrowings - Summary of Short-Term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Ending Balance	$ 117,373	$ 201,853	$ 721,823
Average Balance	$ 142,634	$ 391,547	$ 618,957
Average Rate	0.49%	2.12%	1.74%
Federal funds purchased
Short-term Debt [Line Items]
Ending Balance	$ 0	$ 0	$ 11,000
Average Balance	$ 4,147	$ 8,069	$ 8,801
Average Rate	1.06%	2.53%	2.05%
Borrowings from FHLB
Short-term Debt [Line Items]
Ending Balance	$ 0	$ 136,200	$ 565,000
Average Balance	$ 28,252	$ 278,930	$ 467,594
Average Rate	1.54%	2.62%	2.12%
Securities sold under agreements to repurchase
Short-term Debt [Line Items]
Ending Balance	$ 117,373	$ 65,653	$ 145,823
Average Balance	$ 110,235	$ 104,548	$ 142,562
Average Rate	0.21%	0.75%	0.44%
Maximum [Member]
Short-term Debt [Line Items]
Ending Balance	$ 248,471	$ 670,831	$ 811,026
Weighted Average [Member]
Short-term Debt [Line Items]
Average Rate	0.10%	1.41%	2.17%

Short-term Borrowings - Interes

Short-term Borrowings - Interest Expense on Short-Term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	$ 704	$ 8,298	$ 10,741
Federal funds purchased
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	44	204	180
Borrowings from FHLB
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	434	7,313	9,929
Securities sold under agreements to repurchase
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	$ 226	$ 781	$ 632

Subordinated Debentures - Subor

Subordinated Debentures - Subordinated Debentures Outstanding (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	May 21, 2018
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount	$ 170,612	$ 170,450
First Commonwealth Bank due 2028 [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Due	Jun. 1, 2028
Subordinated Debentures outstanding, Amount	$ 49,314	49,222
First Commonwealth Bank due 2033 [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Due	Jun. 1, 2033
Subordinated Debentures outstanding, Amount	$ 49,131	49,061
First Commonwealth Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Due	Jan. 23, 2034
Subordinated Debentures outstanding, Amount	$ 30,929	30,929
First Commonwealth Capital Trust III [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Due	Apr. 6, 2034
Subordinated Debentures outstanding, Amount	$ 41,238	$ 41,238
First Commonwealth Bank 2028 [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount			$ 50,000
First Commonwealth Bank 2033 [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount			$ 50,000
Subordinated Debt [Member] | LIBOR [Member] | First Commonwealth Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Variable interest rate	2.85%	2.85%
Subordinated Debt [Member] | LIBOR [Member] | First Commonwealth Capital Trust III [Member]
Subordinated Borrowing [Line Items]
Variable interest rate	2.85%	2.85%
Subordinated Debt [Member] | LIBOR [Member] | First Commonwealth Bank 2028 [Member]
Subordinated Borrowing [Line Items]
Variable interest rate	1.845%	1.845%
Debt Instrument, Interest Rate During Period	4.88%	4.88%
Subordinated Debt [Member] | LIBOR [Member] | First Commonwealth Bank 2033 [Member]
Subordinated Borrowing [Line Items]
Variable interest rate	2.37%	2.37%
Debt Instrument, Interest Rate During Period	5.50%	5.50%

Subordinated Debentures - Addit

Subordinated Debentures - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)trustRate	Dec. 31, 2019USD ($)Rate	May 21, 2018USD ($)
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount	$ 170,612	$ 170,450
Number of trusts | trust	2
First Commonwealth Bank 2028 [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount			$ 50,000
Deferred finance costs	$ 900
First Commonwealth Bank 2033 [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount			$ 50,000
Deferred finance costs	1,100
First Commonwealth Capital Trust III [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount	$ 41,238	41,238
Redemption price as percentage of principal amount	100.00%
Deferred finance costs	$ 630
First Commonwealth Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount	$ 30,929	$ 30,929
Redemption price as percentage of principal amount	100.00%
Deferred finance costs	$ 471
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Bank 2028 [Member]
Subordinated Borrowing [Line Items]
Debt Instrument, Interest Rate During Period | Rate	4.88%	4.88%
Variable interest rate	1.845%	1.845%
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Bank 2033 [Member]
Subordinated Borrowing [Line Items]
Debt Instrument, Interest Rate During Period | Rate	5.50%	5.50%
Variable interest rate	2.37%	2.37%
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Capital Trust III [Member]
Subordinated Borrowing [Line Items]
Variable interest rate	2.85%	2.85%
LIBOR [Member] | Subordinated Debt [Member] | First Commonwealth Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Variable interest rate	2.85%	2.85%

Other Long-term Debt (Detail)

Other Long-term Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Amount
Long-term debt	$ 56,258	$ 56,917
Borrowings from FHLB [Member]
Amount
2015	50,685	659
2016	712	50,685
2017	739	712
2018	769	739
2019	799	769
Thereafter	$ 2,554	$ 3,353
2015, Weighted Average Contractual Rate	2.32%	3.84%
2016, Weighted Average Contractual Rate	3.85%	2.32%
2017, Weighted Average Contractual Rate	3.86%	3.85%
2018, Weighted Average Contractual Rate	3.86%	3.86%
2019, Weighted Average Contractual Rate	3.86%	3.86%
Thereafter, Weighted Average Contractual Rate	3.74%	3.77%

Fair Values of Assets and Lia_3

Fair Values of Assets and Liabilities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Random sample percentage of securities for each quarter	100.00%
Total gains or losses included in earnings	$ 0	$ (198,000)
Interest rate swaps transferred into Level 3 from Level 2	0	0
Corporate securities transferred from Level 3 to Level 2	0	0
Impaired loans considered to be credit risk of non-collection	250,000
Updated appraisal requirement floor	250,000
Other real estate owned	1,215,000	2,228,000
Financial instrument of credit risk	104,000	138,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings On Assets Held At Year End	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Between Levels 1 And 2	0	0
Provision for credit losses	53,472,000
Securities available for sale	831,223,000	902,292,000
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or losses included in earnings	0	(198,000)
Interest rate swaps transferred into Level 3 from Level 2	0
Corporate securities transferred from Level 3 to Level 2	$ 0	$ 0

Fair Values of Assets and Lia_4

Fair Values of Assets and Liabilities - Quantitative Inputs and Assumptions Used in Level 3 Fair Value Measurements (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 938,309,000	$ 962,731,000
Other Assets, Fair Value Disclosure	60,981,000	27,689,000
Other investments	12,227,000	16,761,000
Fair Value, Inputs, Level 2 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	930,020,000	955,266,000
Other Assets, Fair Value Disclosure	54,362,000	21,894,000
Other investments	10,557,000	15,091,000
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	8,289,000	7,465,000
Other Assets, Fair Value Disclosure	$ 6,619,000	$ 5,795,000
Other Assets [Member] | Par Value [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input [Extensible List]	Par Value	Par Value
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other investments	$ 1,670,000	$ 1,670,000
Equity Securities [Member] | Par Value [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input [Extensible List]	Carrying Value	Carrying Value
Impaired Loans [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure		$ 2,239,000
Equity Securities, FV-NI, Measurement Input [Extensible List]		Discounted Cash Flow
Impaired Loans [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 798,000	$ 884,000
Equity Securities, FV-NI, Measurement Input [Extensible List]	Gas Reserve study	Gas Reserve study
Impaired Loans [Member] | Discount Rates [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input [Extensible List]		Discount Rate
Impaired Loans [Member] | Discount Rates [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input [Extensible List]	Discount rate	Discount rate
Impaired Loans [Member] | Gas Per Million Cubic Feet [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input [Extensible List]	Gas per MMBTU	Gas per MMBTU
Impaired Loans [Member] | Oil Per Barrels Per Day [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Equity Securities, FV-NI, Measurement Input [Extensible List]	Oil per BBL/d	Oil per BBL/d
Fair Value, Nonrecurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 50,466,000	$ 32,393,000
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	36,862,000	14,875,000
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, Fair Value Disclosure	$ 13,604,000	$ 17,518,000
Maximum [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Input, Discount Rate	9.50%	9.50%
Maximum [Member] | Gas Per Million Cubic Feet [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Weighted Average Inputs Price	$ 1.48	$ 3.49
Maximum [Member] | Oil Per Barrels Per Day [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Weighted Average Inputs Price	$ 36	$ 53.14
Weighted Average [Member] | Impaired Loans [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Input, Discount Rate	10.00%	10.00%
Minimum [Member] | Discounted Cash Flow [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Input, Discount Rate	3.84%	1.90%
Minimum [Member] | Gas Per Million Cubic Feet [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Weighted Average Inputs Price	$ 1.46	$ 2.61
Minimum [Member] | Oil Per Barrels Per Day [Member] | Reserve [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Weighted Average Inputs Price	$ 36	$ 47.09

Fair Values of Assets and Lia_5

Fair Values of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	$ 831,223	$ 902,292
Other investments	10,600	15,100
Other Investments	12,227	16,761
Loans Held for Sale	33,436	15,989
Premises and Equipment	442
Other Assets	60,981	27,689
Total Assets	(938,309)	(962,731)
Other Liabilities	61,308	21,469
Total Liabilities	61,308	21,469
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	7,230	8,341
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	191,180	189,133
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	496,033	661,947
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	100,998	1,000
Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	11,397	17,909
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	24,385	23,962
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Other investments		0
Other Investments	0
Loans Held for Sale	0	0
Premises and Equipment	0
Other Assets	0	0
Total Assets	0	0
Other Liabilities	0	0
Total Liabilities	0	0
Level 1 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 1 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 1 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 1 [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	831,223	902,292
Other Investments	10,557	15,091
Loans Held for Sale	33,436	15,989
Premises and Equipment	442
Other Assets	54,362	21,894
Total Assets	(930,020)	(955,266)
Other Liabilities	61,308	21,469
Total Liabilities	61,308	21,469
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	7,230	8,341
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	191,180	189,133
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	496,033	661,947
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	100,998	1,000
Fair Value, Inputs, Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	11,397	17,909
Fair Value, Inputs, Level 2 [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	24,385	23,962
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Loans Held for Sale	0	0
Premises and Equipment	0
Other Assets	6,619	5,795
Total Assets	(8,289)	(7,465)
Other Liabilities	0	0
Total Liabilities	0	0
Level 3 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Investments	1,670	1,670
Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 3 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 3 [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	$ 0	$ 0

Fair Values of Assets and Lia_6

Fair Values of Assets and Liabilities - Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	$ (831,223)	$ (902,292)
Assets, Fair Value Disclosure	938,309	962,731
Balance, beginning of period	7,465	4,366
Total gains or losses included in earnings	0	198
Total gains or losses included in other comprehensive income	0	0
Purchases	824	2,956
Issuances	0	0
Sales	0	0
Settlements	0	(55)
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance, end of period	8,289	7,465
Other Investments	12,227	16,761
Loans Held-for-sale, Fair Value Disclosure	33,436	15,989
Other Assets, Fair Value Disclosure	60,981	27,689
Other Liabilities, Fair Value Disclosure	61,308	21,469
Financial and Nonfinancial Liabilities, Fair Value Disclosure	61,308	21,469
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	1,670	1,670
Total gains or losses included in earnings	0	0
Total gains or losses included in other comprehensive income	0	0
Purchases	0	0
Issuances	0	0
Sales	0	0
Settlements	0	0
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance, end of period	1,670	1,670
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	5,795	2,696
Total gains or losses included in earnings	0	198
Total gains or losses included in other comprehensive income	0	0
Purchases	824	2,956
Issuances	0	0
Sales	0	0
Settlements	0	(55)
Transfers from Level 3	0	0
Transfers into Level 3	0
Balance, end of period	6,619	5,795
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(24,385)	(23,962)
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(7,230)	(8,341)
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(191,180)	(189,133)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(496,033)	(661,947)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(100,998)	(1,000)
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(11,397)	(17,909)
Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Assets, Fair Value Disclosure	0	0
Other Investments	0
Loans Held-for-sale, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	0	0
Other Liabilities, Fair Value Disclosure	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Level 1 [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Level 1 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(831,223)	(902,292)
Assets, Fair Value Disclosure	930,020	955,266
Other Investments	10,557	15,091
Loans Held-for-sale, Fair Value Disclosure	33,436	15,989
Other Assets, Fair Value Disclosure	54,362	21,894
Other Liabilities, Fair Value Disclosure	61,308	21,469
Financial and Nonfinancial Liabilities, Fair Value Disclosure	61,308	21,469
Fair Value, Inputs, Level 2 [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(24,385)	(23,962)
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(7,230)	(8,341)
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(191,180)	(189,133)
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(496,033)	(661,947)
Fair Value, Inputs, Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(100,998)	(1,000)
Fair Value, Inputs, Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	(11,397)	(17,909)
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Assets, Fair Value Disclosure	8,289	7,465
Loans Held-for-sale, Fair Value Disclosure	0	0
Other Assets, Fair Value Disclosure	6,619	5,795
Other Liabilities, Fair Value Disclosure	0	0
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Other Investments	1,670	1,670
Fair Value, Inputs, Level 3 [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale, at fair value	$ 0	$ 0

Fair Values of Assets and Lia_7

Fair Values of Assets and Liabilities - Schedule of Assets Measured on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 938,309	$ 962,731
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	49,147	29,785
Fair Value Measurement Of Assets On Nonrecurring Basis Net Losses On Impaired Loans	(7,905)	(2,667)
Other Real Estate Owned Assets Fair Value	1,319	2,608
Fair Value Measurement Of Assets On Nonrecurring Basis Net Losses On Other Real Estate Owned	(30)	(196)
Total Assets	50,466	32,393
Fair Value Measurement Of Assets On Nonrecurring Basis Net Loss	(7,935)	(2,863)
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	0	0
Level 1 [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other Real Estate Owned Assets Fair Value	0	0
Total Assets	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	930,020	955,266
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	35,543	12,267
Other Real Estate Owned Assets Fair Value	1,319	2,608
Total Assets	36,862	14,875
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	8,289	7,465
Level 3 [Member] | Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	13,604	17,518
Other Real Estate Owned Assets Fair Value	0	0
Total Assets	$ 13,604	$ 17,518

Fair Values of Assets and Lia_8

Fair Values of Assets and Liabilities - Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	$ 100,009	$ 102,346
Interest-bearing deposits	256,572	19,510
Securities available for sale	831,223	902,292
Debt Securities, Held-to-maturity	361,844	337,123
Other investments	12,227	16,761
Premises and Equipment	442
Loans	6,761,183	6,189,148	$ 5,774,139
Deposits	7,438,666	6,677,615
Short-term borrowings	117,373	201,853	$ 721,823
Long-term debt	56,258	56,917
Subordinated Debentures outstanding, Amount	170,612	170,450
Capital lease obligation	6,385	6,815
Loans Held for Sale	33,436	15,989
Level 1 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Securities available for sale	0	0
Other investments	0
Premises and Equipment	0
Loans Held for Sale	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Securities available for sale	831,223	902,292
Other investments	10,557	15,091
Premises and Equipment	442
Loans Held for Sale	33,436	15,989
Level 3 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Securities available for sale	0	0
Premises and Equipment	0
Loans Held for Sale	0	0
Carrying Amount [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	100,009	102,346
Interest-bearing deposits	256,572	19,510
Securities available for sale	831,223	902,292
Debt Securities, Held-to-maturity	361,844	337,123
Other investments	12,227	16,761
Loans held for sale	33,436	15,989
Loans	6,761,183	6,189,148
Deposits	7,438,666	6,677,615
Short-term borrowings	117,373	201,853
Long-term debt	56,258	56,917
Subordinated Debentures outstanding, Amount	170,612	170,450
Capital lease obligation	6,385	6,815
Estimated Fair Value [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	100,009	102,346
Interest-bearing deposits	256,572	19,510
Securities available for sale	831,223	902,292
Debt Securities, Held-to-maturity	369,851	338,718
Other investments	12,227	16,761
Loans held for sale	33,436	15,989
Loans	7,202,763	6,393,872
Deposits	7,440,906	6,677,595
Short-term borrowings	117,037	201,151
Long-term debt	57,881	58,051
Subordinated Debentures outstanding, Amount	165,665	171,772
Capital lease obligation	6,385	6,815
Estimated Fair Value [Member] | Level 1 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	100,009	102,346
Interest-bearing deposits	256,572	19,510
Securities available for sale	0	0
Debt Securities, Held-to-maturity	0	0
Other investments	0	0
Loans held for sale	0	0
Loans	0	0
Deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Subordinated Debentures outstanding, Amount	0	0
Capital lease obligation	0	0
Estimated Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	0
Interest-bearing deposits	0	0
Securities available for sale	831,223	902,292
Debt Securities, Held-to-maturity	369,851	338,718
Other investments	10,557	15,091
Loans held for sale	33,436	15,989
Loans	35,543	12,267
Deposits	7,440,906	6,677,595
Short-term borrowings	117,037	201,151
Long-term debt	57,881	58,051
Subordinated Debentures outstanding, Amount	0	0
Capital lease obligation	6,385	6,815
Estimated Fair Value [Member] | Level 3 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Securities available for sale	0	0
Debt Securities, Held-to-maturity	0	0
Other investments	1,670	1,670
Loans held for sale	0	0
Loans	7,167,220	6,381,605
Deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Subordinated Debentures outstanding, Amount	165,665	171,772
Capital lease obligation	$ 0	$ 0

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal	$ 21,629	$ 22,942	$ 21,330
State	329	282	298
Total current tax provision	21,958	23,224	21,628
Deferred State and Local Income Tax Expense (Benefit)	(5,070)	2,284	3,666
Deferred State and Local Income Tax Expense (Benefit)	(132)	8	(20)
Deferred Income Tax Expense (Benefit)	(5,202)	2,292	3,646
Total tax provision (benefit), Amount	$ 16,756	$ 25,516	$ 25,274

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Tax at statutory rate, Amount	$ 18,943	$ 27,478	$ 27,882
Income Tax Reconciliation, Bank Owned Life Insurance Income	(1,376)	(1,260)	(1,404)
Tax-exempt interest income, net, Amount	(1,117)	(1,298)	(1,473)
Tax credits, Amount	(44)	(7)	(5)
Other, Amount	195	374	400
Total tax provision (benefit), Amount	$ 16,756	$ 25,516	$ 25,274
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Tax at statutory rate, Pretax Income	21.00%	21.00%	21.00%
Income from bank owned life insurance, Pretax Income	(1.00%)	(1.00%)	(1.00%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	$ 155	$ 229	$ 220
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	0.00%	0.00%	0.00%
Tax-exempt interest income, net, Pretax Income	(1.00%)	(1.00%)	(1.00%)
Tax credits, Pretax Income	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 0	$ 0	$ (346)
Effective Income Tax Rate Reconciliation, Deduction, Percent	0.00%	0.00%	0.00%
Other, Pretax Income	0.00%	0.00%	0.00%
Total tax provision (benefit), Pretax Income	19.00%	19.00%	19.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Operating Loss Carryforwards	$ 1,500,000
Unrecognized Tax Benefits	$ 0
Federal statutory rate	21.00%	21.00%	21.00%
Annual effective income tax rate, percentage	19.00%	19.00%	19.00%
Net deferred tax asset	$ 21,981,000	$ 16,862,000
Alternative minimum tax credit carryforward	0	216,000
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 0	$ 0	$ (346,000)

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Deferred Tax Asset, Tax Deferred Expense, Lease Liability	$ 9,928	$ 11,203
Deferred Tax Assets, Gross [Abstract]
Allowance for credit losses	21,483	10,937
Postretirement benefits other than pensions	242	275
Alternative minimum tax credit carryforward	0	216
Deferred Tax Assets, Operating Loss Carryforwards	385	2,017
Deferred compensation	1,723	1,720
Accrued interest on nonaccrual loans	644	710
Accrued incentives	2,182	2,185
Unfunded loan commitments & other reserves	1,576	964
Other	1,831	1,032
Total deferred tax assets	39,994	31,259
Deferred tax liabilities:
Loan origination fees and costs	(1,280)	(626)
Deferred Tax Liabilities, Leasing Arrangements	9,037	10,302
Net Unrealized Gain On Investment Securities Available For Sale	4,629	1,386
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(2,103)	(1,470)
Section 197 intangibles	(540)	(45)
Other	(424)	(568)
Total deferred tax liabilities	(18,013)	(14,397)
Net deferred tax asset	$ 21,981	$ 16,862

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employer contribution	6.00%
Employee contribution	80.00%
Plan expense	$ 3,900	$ 3,600	$ 3,200
Retirement Plan expense	$ 0	$ 0	$ 0
Minimum [Member]
Eligibility of participants	1.00%
Maximum [Member]
Eligibility of participants	25.00%

Retirement Plans - Schedule of

Retirement Plans - Schedule of Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 0	$ 0	$ 0
Interest cost on projected benefit obligation	23	34	38
Amortization of transition obligation	0	0	0
Gain amortization	(52)	(60)	(35)
Net periodic benefit cost	$ (29)	$ (26)	$ 3

Retirement Plans - Schedule o_2

Retirement Plans - Schedule of Changes in Benefit Obligations and Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0
Interest cost	23	34	38
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Funded Status at End of Year	1,372	834
Unrecognized transition obligation	(537)	0
Unrecognized net gain	308	463
Amounts recognized in retained earnings	1,143	1,297
Change in Benefit Obligation [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	834	883
Service cost	0	0
Interest cost	23	34
Amendments	537	0
Actuarial gain	102	61
Net benefits paid	(124)	(144)
Benefit obligation at end of year	1,372	834	883
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net benefits paid	(124)	(144)
Change In Plan Assets [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Net benefits paid	(124)	(144)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	124	144
Net benefits paid	(124)	(144)
Fair value of plan assets at end of year	$ 0	$ 0	$ 0

Retirement Plans - Schedule o_3

Retirement Plans - Schedule of Amounts Recognized as Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Amounts Recognized in the Statement of Financial Condition as Other liabilities	$ 1,372	$ 834

Retirement Plans - Schedule o_4

Retirement Plans - Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	$ (243)	$ (366)	$ (461)
Transition obligation	424	0	0
Total	181	$ (366)	$ (461)
Postretirement Benefit Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	(27)
Transition obligation	76
Total	$ 49

Retirement Plans - Schedule o_5

Retirement Plans - Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligation (Detail) - Benefit Obligation [Member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Periodic Benefit Cost Assumptions [Line Items]
Discount rate	1.83%	2.88%	4.11%
Health care cost trend: Initial	5.95%	5.55%	6.00%
Health care cost trend: Ultimate	4.75%	4.75%	4.75%
Year ultimate reached	2026	2025	2024

Retirement Plans - Schedule o_6

Retirement Plans - Schedule of Weighted-Average Assumptions Used to Determine Net Periodic Cost (Detail) - Net Periodic Cost [Member]	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Periodic Benefit Cost Assumptions [Line Items]
Discount rate	2.88%	4.11%	3.37%
Health care cost trend: Initial	5.55%	6.00%	6.00%
Health care cost trend: Ultimate	4.75%	4.75%	4.75%
Year ultimate reached	2025	2024	2023
Corridor	10.00%	10.00%	10.00%
Recognition period for gains and losses	10 years 10 months 24 days	12 years 1 month 6 days	12 years 1 month 6 days

Retirement Plans - Schedule o_7

Retirement Plans - Schedule of Impact of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Retirement Benefits [Abstract]
Effect on total of service and interest cost components, One-Percentage-Point Increase	$ 30
Effect on postretirement benefit obligation, One-Percentage-Point Increase	1
Effect on total of service and interest cost components, One-Percentage-Point Decrease	(29)
Effect on postretirement benefit obligation, One-Percentage-Point Decrease	$ 0

Retirement Plans - Schedule o_8

Retirement Plans - Schedule of Projected Benefit Payments (Detail) $ in Thousands	Dec. 31, 2020USD ($)
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2016	$ 165
2017	157
2018	147
2019	136
2020	124
2021 - 2025	$ 455

Incentive Compensation Plan - A

Incentive Compensation Plan - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions

Feb. 20, 2020

Feb. 21, 2019

Nov. 26, 2018

May 29, 2018

Mar. 26, 2018

Feb. 28, 2018

Feb. 26, 2018

Mar. 24, 2017

Feb. 23, 2017

Dec. 19, 2016

Sep. 30, 2016

Sep. 19, 2016

Jun. 07, 2016

Mar. 01, 2016

Mar. 01, 2016

Feb. 18, 2016

Dec. 30, 2015

Jun. 26, 2015

Feb. 05, 2015

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant Price (in dollars per share)

$ 13.72

$ 14.22

$ 14.50

Maximum number of shares that are available to be awarded

5,000,000

Vesting period of restricted stock

0 years

0 years

0 years

0 years

0 years

0 years

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant

2,689,027

Performance Based Stock Awards Vesting Period

3 years

3 years

3 years

3 years

3 years

5 years

Share Based Compensation Arrangement By Share Based Payment Award Percentage Of Target Award Participants Earn

40.00%

40.00%

40.00%

40.00%

40.00%

Performance Shares Awards As Percentage Of Target

100.00%

100.00%

100.00%

100.00%

100.00%

Percentage Of Target Award Opportunities Maximum In Certain Cases

200.00%

200.00%

200.00%

200.00%

200.00%

Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issued (in shares)

95,300

63,000

Grant Price (in dollars per share)

$ 13.72

$ 14.22

Vesting Date

Feb. 20, 2023

Feb. 22, 2022

Vesting period of restricted stock

1 year

1 year

Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issued (in shares)

15,000

2,000

3,000

2,000

77,500

15,000

10,000

33,000

10,000

5,000

10,000

1,000

Grant Price (in dollars per share)

$ 14.22

$ 13.82

$ 15.44

$ 14.08

$ 14.49

$ 13.96

$ 10.09

$ 10.02

$ 9.34

$ 8.84

$ 8.84

$ 9.18

$ 9.84

Vesting Date

Feb. 22, 2022

Nov. 26, 2021

May 29, 2021

Mar. 26, 2021

Feb. 26, 2021

Dec. 19, 2019

Sep. 30, 2019

Sep. 19, 2019

Jun. 7, 2019

Mar. 1, 2019

Mar. 1, 2019

Jun. 26, 2018

Share-based Payment Arrangement, Expense

$ 2.9

$ 2.7

$ 2.6

Unrecognized compensation cost related to unvested restricted stock

$ 3.2

Vesting period of restricted stock

1 year

1 year

1 year

1 year

1 year

3 years

1 year

3 years

1 year

1 year

1 year

1 year

Restricted Stock [Member] | Long Term Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issued (in shares)

50,000

Grant Price (in dollars per share)

$ 8.55

Vesting Date

Feb. 5, 2018

Vesting period of restricted stock

1 year

Time [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant Price (in dollars per share)

$ 13.72

$ 14.22

$ 14.17

$ 13.29

Component 3 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant Price (in dollars per share)

12.43

13.07

13.25

Component 2 [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Grant Price (in dollars per share)

$ 15.37

$ 16.62

$ 15.83

$ 15.09

March 24, 2017 Grant 3 [Member] | Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issued (in shares)

7,000

Grant Price (in dollars per share)

$ 12.99

Vesting Date

Mar. 24, 2020

Vesting period of restricted stock

1 year

March 24, 2017 Grant 1 [Member] | Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares issued (in shares)

5,000

Grant Price (in dollars per share)

$ 12.99

Vesting Date

Mar. 24, 2020

Vesting period of restricted stock

1 year

Incentive Compensation Plan - U

Incentive Compensation Plan - Unvested Service-Based Restricted Stock Awards (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of the year, Shares	171,500	137,500	117,000
Granted, Shares	95,300	78,000	84,500
Vested, Shares	(12,000)	(41,000)	(54,000)
Forfeited, Shares	(4,000)	(3,000)	(10,000)
Outstanding, end of the year, Shares	250,800	171,500	137,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding, beginning of the year, Weighted Average Grant Date Fair Value	$ 14.27	$ 13.05	$ 9.99
Grant Price (in dollars per share)	13.72	14.22	14.50
Vested, Weighted Average Grant Date Fair Value	0	10.09	9.37
Forfeited, Weighted Average Grant Date Fair Value	13.85	14.40	9.34
Outstanding, end of the year, Weighted Average Grant Date Fair Value	$ 14.13	$ 14.27	$ 13.05

Incentive Compensation Plan Inc

Incentive Compensation Plan Incentive Compensation Plan - Restricted Stock Awards Estimated to be Granted on a Performance Award (Details) - $ / shares

Feb. 20, 2020

Feb. 21, 2019

Nov. 26, 2018

May 29, 2018

Mar. 26, 2018

Feb. 28, 2018

Feb. 26, 2018

Feb. 23, 2017

Dec. 19, 2016

Sep. 30, 2016

Sep. 19, 2016

Jun. 07, 2016

Mar. 01, 2016

Mar. 01, 2016

Feb. 18, 2016

Dec. 30, 2015

Jun. 26, 2015

Feb. 05, 2015

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share Based Compensation Arrangement By Share Based Payment Award Percentage Of Target Award Participants Earn

40.00%

40.00%

40.00%

40.00%

40.00%

Performance Shares Awards As Percentage Of Target

100.00%

100.00%

100.00%

100.00%

100.00%

Percentage Of Target Award Opportunities Maximum In Certain Cases

200.00%

200.00%

200.00%

200.00%

200.00%

Vesting period of restricted stock

0 years

0 years

0 years

0 years

0 years

0 years

Performance Based Stock Awards Vesting Period

3 years

3 years

3 years

3 years

3 years

5 years

Grant Price (in dollars per share)

$ 13.72

$ 14.22

$ 14.50

Restricted Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period of restricted stock

1 year

1 year

1 year

1 year

1 year

3 years

1 year

3 years

1 year

1 year

1 year

1 year

Common stock issued to executive

15,000

2,000

3,000

2,000

77,500

15,000

10,000

33,000

10,000

5,000

10,000

1,000

Grant Price (in dollars per share)

$ 14.22

$ 13.82

$ 15.44

$ 14.08

$ 14.49

$ 13.96

$ 10.09

$ 10.02

$ 9.34

$ 8.84

$ 8.84

$ 9.18

$ 9.84

Vesting Date

Feb. 22, 2022

Nov. 26, 2021

May 29, 2021

Mar. 26, 2021

Feb. 26, 2021

Dec. 19, 2019

Sep. 30, 2019

Sep. 19, 2019

Jun. 7, 2019

Mar. 1, 2019

Mar. 1, 2019

Jun. 26, 2018

Restricted Stock [Member] | Long Term Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting period of restricted stock

1 year

Common stock issued to executive

50,000

Grant Price (in dollars per share)

$ 8.55

Vesting Date

Feb. 5, 2018

Restricted Stock Units (RSUs) [Member] | Executive Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock issued to executive

188,700,000

121,900,000

102,000,000

93,500,000

160,650,000

60,000,000

Incentive Compensation Plan -_2

Incentive Compensation Plan - Unvested Target Award (Detail) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of the year, Shares	171,500	137,500	117,000
Granted, Shares	95,300	78,000	84,500
Vested, Shares	(12,000)	(41,000)	(54,000)
Forfeited, Shares	(4,000)	(3,000)	(10,000)
Outstanding, end of the year, Shares	250,800	171,500	137,500
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of the year, Shares	442,832	496,603	525,045
Granted, Shares	188,700	134,929	130,995
Vested, Shares	(134,452)	(188,700)	(149,480)
Forfeited, Shares	0	0	(9,957)
Outstanding, end of the year, Shares	497,080	442,832	496,603

Contingent Liabilities - Additi

Contingent Liabilities - Additional Information (Detail)	Dec. 31, 2020USD ($)
Minimum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses	$ 0
Maximum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses	$ 1,000,000

Revenue Recognition Additional

Revenue Recognition Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Incentive Revenue	$ 0.5
Brokerage Commissions Revenue	$ 3

Revenue Recognition In Scope an

Revenue Recognition In Scope and Out of Scope Revenue Streams (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Fees and Commissions on Debit Cards	$ 23,966	$ 21,677	$ 20,187
Noninterest Income	94,476	85,485	88,637
Trust income	9,101	8,321	7,901
Service charges on deposit accounts	16,387	18,926	18,175
Insurance and retail brokerage commissions	7,850	7,583	7,426
Other income	7,892	7,268	6,790
Out-Of-Scope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Noninterest Income	32,530	24,079	30,258
In-Scope of Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property	967	1,062	982
Noninterest Income	61,946	61,406	58,379
Other income	$ 3,675	$ 3,837	$ 3,708

Related Party Transactions - Lo

Related Party Transactions - Loans to Related Parties (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Loans and Leases Receivable, Related Parties [Roll Forward]
Beginning balance	$ 19,246
Advances	4,258
Repayments	(3,931)
Ending balance	$ 19,573

Regulatory Restrictions and C_3

Regulatory Restrictions and Capital Adequacy - Schedule of Capital Amount and Ratio Considered to be Capitalized (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Common Equity to Risk Weighted Assets	$ 757,231	$ 730,526
Tier 1 Common Equity to Risk Weighted Assets	11.15%	10.91%
Tier 1 Common Equity Required to be Well Capitalized	$ 441,560	$ 435,420
Tier 1 Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Common Equity to Risk Weighted Assets	$ 791,568	$ 759,398
Tier 1 Common Equity to Risk Weighted Assets	11.66%	11.36%
Tier 1 Common Equity Required to be Well Capitalized	$ 441,378	$ 434,575
Tier 1 Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Actual | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets	$ 1,010,608	$ 954,991
Tier I Capital to Risk Weighted Assets	827,231	800,526
Tier I Capital to Average Assets	$ 827,231	$ 800,526
Total Capital to Risk Weighted Assets, Ratio	14.88%	14.26%
Tier I Capital to Risk Weighted Assets, Ratio	12.18%	11.95%
Tier I Capital to Average Assets, Ratio	9.40%	10.17%
Actual | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets	$ 974,911	$ 913,863
Tier I Capital to Risk Weighted Assets	791,568	759,398
Tier I Capital to Average Assets	$ 791,568	$ 759,398
Total Capital to Risk Weighted Assets, Ratio	14.36%	13.67%
Tier I Capital to Risk Weighted Assets, Ratio	11.66%	11.36%
Tier I Capital to Average Assets, Ratio	9.01%	9.66%
Minimum Capital Required | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	$ 713,289	$ 703,370
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	577,424	569,395
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount	352,023	314,963
Tier 1 Common Equity Required for Capital Adequacy	$ 475,526	$ 468,914
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio	10.50%	10.50%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio	8.50%	8.50%
Tier I Capital to Average Assets, Regulatory Minimum Ratio	4.00%	4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets	7.00%	7.00%
Minimum Capital Required | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	$ 712,995	$ 702,006
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	577,186	568,291
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount	351,244	314,338
Tier 1 Common Equity Required for Capital Adequacy	$ 475,330	$ 468,004
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio	10.50%	10.50%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio	8.50%	8.50%
Tier I Capital to Average Assets, Regulatory Minimum Ratio	4.00%	4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets	7.00%	7.00%
Required to be Considered Well Capitalized | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Risk Based Capital Required to be Well Capitalized	$ 543,458	$ 535,901
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Tier One Leverage Capital Required to be Well Capitalized	$ 440,029	$ 393,704
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	$ 679,323	$ 669,877
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	10.00%	10.00%
Required to be Considered Well Capitalized | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Risk Based Capital Required to be Well Capitalized	$ 543,234	$ 534,862
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	8.00%	8.00%
Tier One Leverage Capital Required to be Well Capitalized	$ 439,055	$ 392,922
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	5.00%	5.00%
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	$ 679,043	$ 668,577
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	10.00%	10.00%

Regulatory Restrictions and C_4

Regulatory Restrictions and Capital Adequacy Regulatory Restrictions and Capital Adequacy - Additional Items (Details) $ in Millions	May 21, 2018USD ($)
Additional Items [Abstract]
Subordinated Long-term Debt, Noncurrent	$ 100

Capital - Additional Informatio

Capital - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2021	Mar. 04, 2019	Oct. 24, 2018	Dec. 31, 2017	Feb. 17, 2016	Jan. 28, 2014	Jan. 29, 2013
Subsequent Event [Line Items]
Announcement of common stock repurchase program					$ 25,000	$ 25,000		$ 25,000	$ 25,000	$ 25,000
Stock repurchased (in shares)	2,761,504	1,843,373
Average price per share	$ 9.07	$ 13.58
Shareholders' equity	$ 1,068,617	$ 1,055,665	$ 975,389				$ 888,127
Increase (decrease) in equity	13,000
Net Income	73,447	105,333	107,498
Proceeds from issuance of treasury stock	1,800
Increase (decrease) in fair value of available for sale investments	11,700
Payments of dividends	42,982	39,394	34,849
Purchase of treasury stock	20,905	$ 6,259	$ 26,189
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 11,199						$ (1,344)
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.44	$ 0.40	$ 0.35
Subsequent Event
Subsequent Event [Line Items]
Announcement of common stock repurchase program				$ 25,000

Condensed Financial Informati_3

Condensed Financial Information of First Commonwealth Financial Corporation (Parent Company Only) - Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets
Loans	$ 6,659,874	$ 6,137,511
Premises and equipment, net	125,517	137,268
Other assets	143,415	97,328
Total assets	9,068,104	8,308,773
Liabilities and Shareholders' Equity
Subordinated Debentures outstanding, Amount	170,612	170,450
Shareholders' equity	1,068,617	1,055,665	$ 975,389	$ 888,127
Total liabilities and shareholders’ equity	9,068,104	8,308,773
Parent Company [Member]
Assets
Cash	34,427	22,889
Loans	11	13
Investment in subsidiaries	1,108,801	1,086,844
Investment in unconsolidated subsidiary trusts	2,182	2,190
Investment in Jointly-Owned Company	338	306
Premises and equipment, net	3,476	3,801
Receivables From Subsidiaries	0	4,750
Dividends receivable from subsidiaries	3,038	5,097
Other assets	7,307	6,924
Total assets	1,159,580	1,132,814
Liabilities and Shareholders' Equity
Accrued expenses and other liabilities	18,796	4,983
Subordinated Debentures outstanding, Amount	72,167	72,167
Shareholders' equity	1,068,617	1,055,664
Total liabilities and shareholders’ equity	$ 1,159,580	$ 1,132,814

Condensed Financial Informati_4

Condensed Financial Information of First Commonwealth Financial Corporation (Parent Company Only) - Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Interest and dividends	$ 301,209	$ 325,264	$ 292,257
Interest expense	(32,938)	(55,402)	(40,035)
Other income	7,892	7,268	6,790
Applicable income tax (provision) benefits	(16,756)	(25,516)	(25,274)
Net Income	73,447	105,333	107,498
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and dividends	8	8	1
Dividends from subsidiaries	61,708	55,964	81,851
Interest expense	(3,229)	(3,735)	(3,722)
Other income	3	6	14
Operating expense	(4,687)	(4,525)	(4,047)
Income (loss) before taxes and equity in undistributed earnings of subsidiaries	53,803	47,718	74,097
Applicable income tax (provision) benefits	1,648	1,720	1,324
Income (loss) before equity in undistributed earnings of subsidiaries	55,451	49,438	75,421
Equity in undistributed (loss) earnings of subsidiaries	17,996	55,895	32,077
Net Income	$ 73,447	$ 105,333	$ 107,498

Condensed Financial Informati_5

Condensed Financial Information of First Commonwealth Financial Corporation (parent company only) - Statements of Cash Flow (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net Income	$ 73,447	$ 105,333	$ 107,498
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	11,653	10,370	8,046
Other net	5,349	(14,310)	11,695
Net cash provided by operating activities	105,699	107,632	135,263
Investing Activities
Net cash (used in) provided by investing activities	(483,138)	122,942	(347,748)
Financing Activities
Dividends paid	(42,982)	(39,394)	(34,849)
Proceeds from reissuance of treasury stock	222	211	208
Purchase of treasury stock	(20,905)	(6,259)	(26,189)
Net cash provided by (used in) financing activities	612,164	(207,665)	204,140
Parent Company [Member]
Operating Activities
Net Income	73,447	105,333	107,498
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	383	340	320
Net gains on sales of assets	0	(2)	(7)
Decrease (increase) in prepaid income taxes	(317)	629	37
Undistributed equity in subsidiaries	(17,996)	(55,895)	(32,077)
Proceeds from Equity Method Investment, Distribution	0	0	9,000
Other net	19,705	(2,957)	(1,628)
Net cash provided by operating activities	75,222	47,448	83,143
Investing Activities
Net change in loans	1	1	3
Payments to Acquire Property and Equipment	(20)	(586)	(87)
Proceeds from sale of other assets	0	2	7
Payments to Acquire Additional Interest in Subsidiaries	0	0	(17,202)
Net cash (used in) provided by investing activities	(19)	(583)	(17,279)
Financing Activities
Dividends paid	(42,982)	(39,394)	(34,849)
Proceeds from reissuance of treasury stock	222	211	208
Purchase of treasury stock	(20,905)	(6,259)	(26,189)
Net cash provided by (used in) financing activities	(63,665)	(45,442)	(60,830)
Net (decrease) increase in cash and cash equivalents	11,538	1,423	5,034
Cash and cash equivalents at January 1	22,889	21,466	16,432
Cash and cash equivalents at December 31	$ 34,427	$ 22,889	$ 21,466

Condensed Financial Informati_6

Condensed Financial Information of First Commonwealth Financial Corporation (Parent Company Only) - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.44	$ 0.40	$ 0.35
Line of credit	$ 20,000,000
Borrowings	$ 0	$ 0	$ 0

Subsequent Event (Details)

Subsequent Event (Details) - USD ($) $ in Millions	Jan. 31, 2021	Mar. 04, 2019	Oct. 24, 2018	Feb. 17, 2016	Jan. 28, 2014	Jan. 29, 2013
Subsequent Event [Line Items]
Announcement of common stock repurchase program		$ 25	$ 25	$ 25	$ 25	$ 25
Subsequent Event
Subsequent Event [Line Items]
Announcement of common stock repurchase program	$ 25