First Commonwealth Financial (FCF) 10-K 29 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 26, 2016	Jun. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	FCF
Entity Registrant Name	FIRST COMMONWEALTH FINANCIAL CORP /PA/
Entity Central Index Key	712,537
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		88,961,268
Entity Public Float			$ 851,661,514

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 66,644,000	$ 72,276,000
Interest-bearing bank deposits	2,808,000	2,262,000
Securities available for sale, at fair value	(886,560,000)	(1,309,819,000)
Securities held to maturity, at amortized cost, (Fair value $382,341 at December 31, 2015)	384,324,000	0
Other investments	62,952,000	44,545,000
Loans held for sale	5,763,000	2,502,000
Loans:
Portfolio loans	4,683,750,000	4,457,308,000
Allowance for credit losses	(50,812,000)	(52,051,000)
Net loans	4,632,938,000	4,405,257,000
Premises and equipment, net	63,454,000	64,989,000
Other real estate owned	9,398,000	7,197,000
Goodwill	164,500,000	161,429,000
Amortizing intangibles, net	1,231,000	1,665,000
Bank owned life insurance	182,601,000	177,567,000
Other assets	103,717,000	110,777,000
Total assets	6,566,890,000	6,360,285,000
Deposits (all domestic):
Noninterest-bearing	1,116,689,000	989,027,000
Interest-bearing	3,079,205,000	3,326,484,000
Total deposits	4,195,894,000	4,315,511,000
Short-term borrowings	1,510,825,000	1,105,876,000
Subordinated debentures	72,167,000	72,167,000
Other long-term debt	9,314,000	89,459,000
Total long-term debt	81,481,000	161,626,000
Other liabilities	59,144,000	61,127,000
Total liabilities	5,847,344,000	5,644,140,000
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; 105,563,455 shares issued as of December 31, 2015 and 2014; and 88,961,268 shares and 91,723,028 shares outstanding at December 31, 2015 and 2014, respectively	105,563,000	105,563,000
Additional paid-in capital	365,981,000	365,615,000
Retained earnings	378,081,000	353,027,000
Accumulated other comprehensive (loss) income, net	(2,386,000)	(4,499,000)
Treasury stock (16,602,187 and 13,840,427 shares at December 31, 2015 and 2014, respectively)	(127,693,000)	(103,561,000)
Total shareholders’ equity	719,546,000	716,145,000
Total liabilities and shareholders’ equity	$ 6,566,890,000	$ 6,360,285,000

CONSOLIDATED STATEMENTS OF FIN3

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Securities held to maturity, fair value	$ 382,341
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)	105,563,455	105,563,455
Common stock, shares outstanding (in shares)	88,961,268	91,723,028
Treasury stock, shares (in shares)	16,602,187	13,840,427

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest Income
Interest and fees on loans	$ 172,819	$ 171,196	$ 176,129
Interest and dividends on investments:
Taxable interest	26,807	28,767	29,916
Interest exempt from federal income taxes	997	311	4
Dividends	3,434	1,895	302
Interest on bank deposits	14	12	7
Total interest income	204,071	202,181	206,358
Interest Expense
Interest on deposits	7,474	12,453	15,596
Interest on short-term borrowings	5,018	2,449	1,262
Interest on subordinated debentures	2,329	2,292	3,128
Interest on other long-term debt	774	1,307	1,721
Total interest expense	15,595	18,501	21,707
Net Interest Income	188,476	183,680	184,651
Provision for credit losses	14,948	11,196	19,227
Net Interest Income after Provision for Credit Losses	173,528	172,484	165,424
Noninterest Income
Net securities (losses) gains	(153)	550	(1,158)
Trust income	5,834	6,000	6,166
Service charges on deposit accounts	15,319	15,661	15,652
Insurance and retail brokerage commissions	8,522	6,483	6,005
Income from bank owned life insurance	5,412	5,502	5,539
Gain on sale of loans	2,819	516	624
Gain on sale of assets	1,457	4,480	1,529
Card related interchange income	14,501	14,222	13,746
Other income	7,614	7,445	12,060
Total noninterest income	61,325	60,859	60,163
Noninterest Expense
Salaries and employee benefits	89,161	87,223	86,012
Net occupancy	13,712	13,119	13,607
Furniture and equipment	10,737	17,812	15,118
Data processing	6,123	6,124	6,009
Advertising and promotion	2,638	2,953	3,129
Pennsylvania shares tax	4,693	3,776	5,638
Intangible amortization	605	631	1,064
Collection and repossession	2,826	2,754	3,836
Other professional fees and services	4,034	3,986	3,731
FDIC insurance	4,014	4,054	4,366
Loss on sale or write-down of assets	3,112	1,595	1,054
Litigation and operational losses	2,119	6,786	1,115
Loss on early redemption of subordinated debt	0	0	1,629
Conversion related	0	1,788	2,588
Merger and acquisition related	922	0	0
Other operating expenses	19,178	18,609	19,928
Total noninterest expense	163,874	171,210	168,824
Income before income taxes	70,979	62,133	56,763
Income tax provision	20,836	17,680	15,281
Net Income	$ 50,143	$ 44,453	$ 41,482
Average Shares Outstanding (in shares)	89,356,767	93,114,654	97,028,157
Average Shares Outstanding Assuming Dilution (in shares)	89,356,767	93,114,654	97,029,832
Per Share Data:
Basic Earnings Per Share (in dollars per share)	$ 0.56	$ 0.48	$ 0.43
Diluted Earnings Per Share (in dollars per share)	0.56	0.48	0.43
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.28	$ 0.28	$ 0.23

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net Income	$ 50,143	$ 44,453	$ 41,482
Other comprehensive income (loss), before tax expense (benefit):
Unrealized holding gains (losses) on securities arising during the period	2,798	25,153	(34,975)
Less: reclassification adjustment for losses (gains) on securities included in net income	153	(550)	1,158
Unrealized holding gains on derivatives arising during the period	450	472	0
Reclassification adjustment for gains on derivatives included in net income	(49)	(10)	0
Unrealized (losses) gains for postretirement obligations:
Transition obligation	0	0	0
Net (loss) gain	(102)	(313)	219
Total other comprehensive income (loss), before tax expense (benefit)	3,250	24,752	(33,598)
Income tax expense (benefit) related to items of other comprehensive income (loss)	1,137	8,663	(11,751)
Comprehensive Income	$ 52,256	$ 60,542	$ 19,635

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]
Beginning balance at Dec. 31, 2012	$ 746,007	$ 105,563	$ 365,354	$ 315,608	$ 1,259	$ (41,777)
Beginning balance, Shares Outstanding at Dec. 31, 2012		99,629,494
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	41,482			41,482
Total other comprehensive (loss) Income	(21,847)				(21,847)
Cash dividends declared	(22,344)			$ (22,344)
Discount on dividend reinvestment plan purchases	(112)		(112)
Treasury stock acquired	(32,217)					(32,217)
Treasury stock acquired, Shares Outstanding		(4,462,638)
Treasury stock reissued	176		0	$ 0		176
Treasury stock reissued, Shares Outstanding		25,359
Restricted stock	552	$ 0	91	2		459
Restricted stock, Shares Outstanding		53,000
Ending balance at Dec. 31, 2013	711,697	$ 105,563	365,333	334,748	(20,588)	(73,359)
Ending balance, Shares Outstanding at Dec. 31, 2013		95,245,215
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	44,453			44,453
Total other comprehensive (loss) Income	16,089				16,089
Cash dividends declared	(26,174)			(26,174)
Discount on dividend reinvestment plan purchases	(65)		(65)
Treasury stock acquired	(30,956)					(30,956)
Treasury stock acquired, Shares Outstanding		(3,636,634)
Treasury stock reissued	192		35	0		157
Treasury stock reissued, Shares Outstanding		21,960
Restricted stock	909	$ 0	312	0		597
Restricted stock, Shares Outstanding		92,487
Ending balance at Dec. 31, 2014	$ 716,145	$ 105,563	365,615	353,027	(4,499)	(103,561)
Ending balance, Shares Outstanding at Dec. 31, 2014	91,723,028	91,723,028
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 50,143			50,143
Total other comprehensive (loss) Income	2,113				2,113
Cash dividends declared	(25,089)			(25,089)
Treasury stock acquired	(25,383)					(25,383)
Treasury stock acquired, Shares Outstanding		(2,918,066)
Treasury stock reissued	192		32	0		160
Treasury stock reissued, Shares Outstanding		20,936
Restricted stock	1,425	$ 0	334	0		1,091
Restricted stock, Shares Outstanding		135,370
Ending balance at Dec. 31, 2015	$ 719,546	$ 105,563	$ 365,981	$ 378,081	$ (2,386)	$ (127,693)
Ending balance, Shares Outstanding at Dec. 31, 2015	88,961,268	88,961,268

CONSOLIDATED STATEMENTS OF CHA7

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.28	$ 0.28	$ 0.23
Common Stock [Member]
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.28	$ 0.28	$ 0.23

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities
Net Income	$ 50,143	$ 44,453	$ 41,482
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	14,948	11,196	19,227
Deferred tax expense	12,653	4,862	12,704
Depreciation and amortization	7,640	13,721	11,090
Net (gains) losses on securities and other assets	(729)	2,832	431
Net amortization of premiums and discounts on securities	2,793	2,233	543
Net amortization of premiums and discounts on long-term debt	0	(37)	(117)
Income from increase in cash surrender value of bank owned life insurance	5,412	5,275	5,539
Payments for Origination of Mortgage Loans Held-for-sale	(86,576)	(17,697)	0
Proceeds from Sale of Mortgage Loans Held-for-sale	85,718	15,598	0
(Increase) decrease in interest receivable	(41)	542	921
Decrease in interest payable	(103)	(404)	(1,172)
Decrease in prepaid FDIC insurance	0	0	9,205
(Increase) decrease in income taxes payable	(354)	1,860	(615)
Other—net	(7,929)	8,253	(2,426)
Net cash provided by operating activities	72,751	82,137	85,734
Transactions with securities held to maturity:
Proceeds from maturities and redemptions	9,358	0	0
Purchases	(380,877)	0	0
Transactions with securities available for sale:
Proceeds from sales	88,054	132,868	671
Proceeds from maturities and redemptions	373,228	242,895	356,667
Purchases	(24,150)	(339,649)	(539,894)
Purchases of FHLB stock	(65,605)	(40,920)	(18,120)
Proceeds from the redemption of FHLB stock	48,029	31,819	10,904
Proceeds from bank owned life insurance	378	2,080	2,092
Proceeds from the sale of loans	3,018	3,112	20,760
Proceeds from sales of other assets	6,407	12,882	12,713
Acquisition, net of cash acquired	(3,533)	(3,042)	0
Net increase in loans	(191,853)	(195,120)	(143,438)
Purchases of premises and equipment	(4,887)	(10,980)	(9,635)
Net cash used in investing activities	(142,433)	(164,055)	(307,280)
Financing Activities
Net decrease in federal funds purchased	(5,000)	(7,000)	(18,000)
Net increase in other short-term borrowings	409,949	486,261	288,387
Net (decrease) increase in deposits	(209,928)	(288,352)	46,006
Repayments of other long-term debt	(80,145)	(59,889)	(29,969)
Proceeds from issuance of long-term debt	0	5,000	0
Repayments of subordinated debentures	0	0	(34,702)
Discount on dividend reinvestment plan purchases	0	(65)	(112)
Dividends paid	(25,089)	(26,174)	(22,344)
Proceeds from reissuance of treasury stock	192	192	176
Purchase of treasury stock	(25,383)	(30,956)	(33,439)
Net cash provided by financing activities	64,596	79,017	196,003
Net (decrease) increase in cash and cash equivalents	(5,086)	(2,901)	(25,543)
Cash and cash equivalents at January 1	74,538	77,439	102,982
Cash and cash equivalents at December 31	$ 69,452	$ 74,538	$ 77,439

Statement of Accounting Policie

Statement of Accounting Policies	12 Months Ended
	Dec. 31, 2015
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. 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, an insurance agency and a financial advisor, 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 fifteen counties in central and western Pennsylvania as well as in central 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. 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 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 and equity 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 determine whether other-than-temporary impairment has occurred. Issuer-specific securities whose market values have fallen below their book values are initially selected for more in-depth analysis based on the percentage decline in value and duration of the decline. 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. Pooled trust preferred collateralized debt obligations are measured by evaluating all relevant credit and structural aspects, determining appropriate performance assumptions and performing a discounted cash flow analysis. This evaluation includes detailed credit, performance and structural evaluations for each piece of collateral. Other factors in the pooled trust preferred collateralized debt obligations valuation include terms of the structure, the cash flow waterfall (for both interest and principal), the over collateralization and interest coverage tests and events of default/liquidation. Based on this review, a determination is made on a case by case basis as to a potential impairment. Declines in the fair value of individual securities below their cost that are not expected to be recovered will result in write-downs of the individual securities to their fair value. The related write-downs are included in earnings as impairment losses. 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 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. A loan is considered to be impaired when, based on current information and events, it is probable that First Commonwealth will be unable to collect principal or interest that is due in accordance with contractual terms of the loan. Impaired 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 impaired 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 collectibility 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. 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 First Commonwealth maintains an allowance for credit losses at a level deemed sufficient to absorb losses that are inherent in the loan portfolio. First Commonwealth’s management determines and reviews with the Board of Directors the adequacy of the allowance on a quarterly basis to ensure that the provision for credit losses has been charged against earnings in an amount necessary to maintain the allowance at a level that is appropriate based on management’s assessment of probable estimated losses. First Commonwealth’s methodology for assessing the appropriateness of the allowance for credit losses consists of several key elements. These elements include an assessment of individual problem loans, delinquency and loss experience trends and other relevant factors, all of which may be susceptible to significant changes. 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 10, "Loans and Allowance for Credit Losses." First Commonwealth consistently applies the following comprehensive methodology and procedure for determining the allowance for credit losses. All impaired credits in excess of $100 thousand are individually reviewed quarterly. A specific reserve is established for impaired loans that is equal to the total amount of probable unconfirmed losses for the impaired loans that are reviewed. Based on this reserve as a percentage of reviewed loan balances, a reserve is also established for the impaired loan balances that are not individually reviewed. The allowance calculation uses 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. An additional component of the allowance is determined by management based on a qualitative analysis of certain factors related to portfolio risks and economic conditions. Factors considered by management include employment trends, macroeconomic trends, commercial real estate trends and the overall lending environment. 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. Management determines the adequacy of the allowance on a quarterly basis, charging the provision against earnings in an amount necessary to maintain the allowance at a level that is appropriate based on management’s assessment of probable estimated losses. The Company’s methodology for assessing the appropriateness of the allowance for off-balance sheet credit exposure consists of analysis of historical usage trends as well as loss history and probability of default rates related to the off-balance sheet category. 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 a determined probability of default as well as a loss given default. This amount is adjusted quarterly and reported as part of other operating expenses on the Consolidated Statements of Income. 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. 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 $3.7 million and $3.9 million as of December 31, 2015 and 2014 , respectively, and is reflected in "Other Liabilities" on the Consolidated Statements of Financial Condition. Premises and Equipment 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 seven years. 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 by applying a fair value based test. First Commonwealth reviews goodwill annually and again at any quarter-end if a material event occurs during the quarter that may affect goodwill. If goodwill testing is required, an assessment of qualitative factors can be completed before performing the two step goodwill impairment test. If an assessment of qualitative factors determines it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, then the two step goodwill impairment test is not required. 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 the effective portion 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. Employee Stock Ownership Plan Accounting treatment for First Commonwealth’s Employee Stock Ownership Plan (“ESOP”) described in Note 21 “Unearned ESOP Shares” follows FASB ASC Topic 718, “Compensation—Stock Compensation” for ESOP shares acquired after December 31, 1992 (“new shares”). First Commonwealth’s ESOP borrowed funds were guaranteed by First Commonwealth. The ESOP shares purchased subject to the debt guaranteed by First Commonwealth were recorded as a reduction of common shareholders’ equity by recording unearned ESOP shares. Shares were committed to be released to the ESOP Trust for allocation to plan participants through loan payments. As the shares were committed to be released, the unearned ESOP shares account was credited for the average cost of the shares collateralizing the ESOP borrowed funds. Compensation cost was recognized for these shares in accordance with the provisions of FASB ASC Topic 718 and was based upon the fair market value of the shares that were committed to be released. Additional paid-in capital was charged or credited for the difference between the fair value of the shares committed to be released and the cost of those shares to the ESOP. The borrowed funds related to the unearned ESOP shares were paid off in November 2012. Dividends on unallocated ESOP shares were used for debt service and are reported as a reduction of debt and accrued interest payable. Dividends on allocated ESOP shares were charged to retained earnings and allocated or paid to the plan participants. The average number of common shares outstanding used in calculating earnings per share excludes all unallocated ESOP shares. 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 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, 2015 , First Commonwealth has interest derivative positions 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 less any unallocated ESOP shares. 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 compensatory stock options outstanding and 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 1 securities include equity holdings comprised of publicly traded bank stocks which were priced using quoted market prices. • 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, interest rate derivatives that include interest rate swaps, risk participation agreements and foreign currency contracts, certain other real estate owned and certain impaired 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 select Obligations of States and Political Subdivisions, corporate securities, pooled trust preferred collateralized debt obligations, nonmarketable equity investments, certain other real estate owned, certain impaired loans and loans held for sale. 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 18 “Fair Values of Assets and Liabilities” for additional information.

New Accounting Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements In January 2015, the FASB issued ASU No. 2015-01, “Income Statement - Extraordinary and Unusual Items (Subtopic 225-20), ” which finalizes Proposed ASU No. 2014-220, and eliminates the concept of extraordinary items from U.S. GAAP. Accordingly, this ASU eliminates FASB ASC Subtopic 225-20, "Income Statement - Extraordinary and Unusual Items", which, until now, required that an entity separately classify, present, and disclose extraordinary events and transactions. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In September 2015, the FASB issued ASU No. 2015-16, “Business Combinations (Topic 805), ” which requires that the acquirer recognize adjustments to provisional amounts identified during the measurement period in the reporting period in which the adjustment amounts are determined. The adjustments are required to be presented separately on the face of the income statement or disclosed in the notes to show the portion of current-period earnings by line item that would have been recorded in previous reporting periods if the adjustments to the provisional amounts had been recognized as of the acquisition date. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In August 2015, the FASB issued ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606) ” . In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)", with an original effective date for annual reporting periods beginning after December 15, 2016. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2015-14 deferred the effective date of ASU 2014-09 to annual periods and interim periods within those annual periods beginning after December 15, 2017. We are currently evaluating the potential impact of ASU 2015-14 on our financial statements. In January 2016, the FASB issued ASU 2016-1, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. ” ASU 2016-1, among other things, (i) requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income, (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iii) eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet, (iv) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, (v) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments, (vi) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements and (viii) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities. ASU 2016-1 will be effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is not expected to have a significant impact on our financial statements

Supplemental Comprehensive Inco

Supplemental Comprehensive Income Disclosures	12 Months Ended
	Dec. 31, 2015
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. 2015 2014 2013 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 (losses) on securities arising during the period $ 2,798 $ (978 ) $ 1,820 $ 25,153 $ (8,803 ) $ 16,350 $ (34,975 ) $ 12,233 $ (22,742 ) Reclassification adjustment for losses (gains) on securities included in net income 153 (54 ) 99 (550 ) 193 (357 ) 1,158 (405 ) 753 Total unrealized gains (losses) on securities 2,951 (1,032 ) 1,919 24,603 (8,610 ) 15,993 (33,817 ) 11,828 (21,989 ) Unrealized gains (losses) on derivatives: Unrealized holding gains on derivatives arising during the period 450 (158 ) 292 472 (165 ) 307 — — — Reclassification adjustment for gains on derivatives included in net income (49 ) 17 (32 ) (10 ) 3 (7 ) — — — Total unrealized gains on derivatives 401 (141 ) 260 462 (162 ) 300 — — — Unrealized (losses) gains for postretirement obligations: Transition obligation — — — — — — — — — Net (loss) gain (102 ) 36 (66 ) (313 ) 109 (204 ) 219 (77 ) 142 Total unrealized (losses) gains for postretirement obligations (102 ) 36 (66 ) (313 ) 109 (204 ) 219 (77 ) 142 Total other comprehensive income (loss) $ 3,250 $ (1,137 ) $ 2,113 $ 24,752 $ (8,663 ) $ 16,089 $ (33,598 ) $ 11,751 $ (21,847 ) The following table details the change in components of OCI for the year-ended December 31: 2015 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (4,875 ) $ 300 $ 76 $ (4,499 ) Other comprehensive income before reclassification adjustment 1,820 292 2,112 Amounts reclassified from accumulated other comprehensive income (loss) 99 (32 ) 67 Net gain (66 ) (66 ) Net other comprehensive income during the period 1,919 260 (66 ) 2,113 Balance at December 31 $ (2,956 ) $ 560 $ 10 $ (2,386 ) 2014 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (20,868 ) $ — $ 280 $ (20,588 ) Other comprehensive income before reclassification adjustment 16,350 307 16,657 Amounts reclassified from accumulated other comprehensive income (loss) (357 ) (7 ) (364 ) Net gain (204 ) (204 ) Net other comprehensive income during the period 15,993 300 (204 ) 16,089 Balance at December 31 $ (4,875 ) $ 300 $ 76 $ (4,499 ) 2013 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ 1,121 $ — $ 138 $ 1,259 Other comprehensive income before reclassification adjustment (22,742 ) — (22,742 ) Amounts reclassified from accumulated other comprehensive income (loss) 753 — 753 Net gain 142 142 Net other comprehensive income during the period (21,989 ) — 142 (21,847 ) Balance at December 31 $ (20,868 ) $ — $ 280 $ (20,588 )

Supplemental Cash Flow Disclosu

Supplemental Cash Flow Disclosures	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 2013 (dollars in thousands) Cash paid during the period for: Interest $ 15,818 $ 18,943 $ 23,022 Income taxes 8,331 10,700 3,080 Non-cash investing and financing activities: Loans transferred to other real estate owned and repossessed assets 8,257 5,061 12,326 Other real estate owned sold and settled out of period — — 348 Fair value of loans transferred from held to maturity to available for sale 3,196 3,035 20,135 Gross increase (decrease) in market value adjustment to securities available for sale 2,949 24,601 (33,792 ) Gross increase in market value adjustment to derivatives 401 472 — Investments committed to purchase, not settled 694 — — Net assets acquired through acquisition 463 — — Contribution of premises — 682 —

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 2013 Weighted average common shares issued 105,563,455 105,563,455 105,563,455 Average treasury shares (16,045,900 ) (12,294,217 ) (8,363,083 ) Average unearned nonvested shares (160,788 ) (154,584 ) (172,215 ) Weighted average common shares and common stock equivalents used to calculate basic earnings per share 89,356,767 93,114,654 97,028,157 Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share — — 1,675 Weighted average common shares and common stock equivalents used to calculate diluted earnings per share 89,356,767 93,114,654 97,029,832 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. 12/31/2015 12/31/2014 12/31/2013 Price Range Price Range Price Range Shares From To Shares From To Shares From To Stock Options — $ — $ — 15,000 $ 14.55 $ 14.55 27,000 $ 14.41 $ 14.55 Restricted Stock 92,002 6.82 9.84 106,977 5.26 9.26 81,770 4.41 7.57

Cash and Due from Banks

Cash and Due from Banks	12 Months Ended
	Dec. 31, 2015
Cash and Due from Banks [Abstract]
Cash and Due from Banks	Cash and Due from Banks Regulations 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 Federal Reserve Bank. First Commonwealth Bank maintained average balances of $4.6 million during 2015 and $4.9 million during 2014 with the Federal Reserve Bank.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2015
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 sixteen 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 four 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 that are not designated as hedging instruments. These derivatives relate to contracts that First Commonwealth enters into with loan customers providing 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 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 The Company has entered into four interest rate swap contracts which were designated as cash flow hedges. The interest rate swaps have a total notional amount of $200.0 million , $85.0 million with an original maturity of three years and $115.0 million with an original maturity of four years . 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 on commercial loans benchmarked to the 1-month LIBOR rate. Therefore, the interest rate swaps convert the interest payments on the first $200.0 million of 1-month LIBOR based commercial loans into fixed rate payments. The periodic net settlement of interest rate swaps is recorded as an adjustment to "Interest and fees on loans" in the Consolidated Statement of Income. For the years ended December 31, 2015 and 2014 , interest income was increased by $2.0 million and $0.3 million , respectively, as a result of these interest rate swaps. Changes in the fair value of the effective portion of cash flow hedges are reported in OCI. When the cash flows associated with the hedged item are realized, the gain or loss included in OCI is recognized in Interest and fees on loans, the same line item in the Consolidated Statement of Income as the income on the hedged items. The cash flow hedges were highly effective at December 31, 2015 and December 31, 2014 and changes in the fair value attributed to hedge ineffectiveness were not material. There were no cash flow hedges at December 31, 2013 . The following table depicts the credit value adjustment recorded related to the notional amount of derivatives outstanding as well as the notional amount of risk participation agreements participated to other banks at December 31 : 2015 2014 (dollars in thousands) Derivatives not Designated as Hedging Instruments Credit value adjustment $ (542 ) $ (268 ) Notional Amount: Interest rate derivatives 276,860 273,388 Interest rate caps 22,793 6,656 Risk participation agreements 126,612 113,624 Sold credit protection on risk participation agreements (20,383 ) (17,296 ) Derivatives Designated as Hedging Instruments Fair value adjustment 922 472 Notional Amount - Interest rate derivatives 200,000 100,000 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 : 2015 2014 2013 (dollars in thousands) Non-hedging interest rate derivatives: (Decrease) increase in other income $ (274 ) $ (345 ) $ 1,428 Hedging interest rate derivatives: Increase in interest income 2,049 330 — Increase in other income 64 10 — The fair value of our derivatives is included in a table in Note 18, “Fair Values of Assets and Liabilities,” in the line items “Other assets” and “Other liabilities.”

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 20,034 $ 2,071 $ (13 ) $ 22,092 $ 23,344 $ 2,595 $ (3 ) $ 25,936 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 778,476 7,983 (8,882 ) 777,577 947,635 13,076 (9,830 ) 950,881 Mortgage-Backed Securities – Commercial 28 — — 28 72 2 — 74 Other Government-Sponsored Enterprises 19,201 2 (85 ) 19,118 269,181 4 (1,308 ) 267,877 Obligations of States and Political Subdivisions 27,066 532 — 27,598 27,058 362 (43 ) 27,377 Corporate Securities 1,897 422 — 2,319 6,682 573 — 7,255 Pooled Trust Preferred Collateralized Debt Obligations 42,239 916 (7,497 ) 35,658 41,926 309 (13,236 ) 28,999 Total Debt Securities 888,941 11,926 (16,477 ) 884,390 1,315,898 16,921 (24,420 ) 1,308,399 Equities 2,170 — — 2,170 1,420 — — 1,420 Total Securities Available for Sale $ 891,111 $ 11,926 $ (16,477 ) $ 886,560 $ 1,317,318 $ 16,921 $ (24,420 ) $ 1,309,819 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. In 2015, a $0.3 million loss was recognized on the sale of approximately $75.0 million of low-yielding U.S. government agency securities. Proceeds from the sale of these securities were reinvested into higher yielding mortgage-backed securities. During 2014, a gain of $0.5 million was recognized as the result of a recovery on a trust preferred security for which a $1.3 million loss was recognized in 2013 due to the early redemption of a pooled trust preferred security with a book value of $6.6 million . Senior note holders elected to liquidate all assets of the trust, resulting in losses for the mezzanine notes owned by First Commonwealth. The gain recognized in 2014 was a result of additional proceeds distributed as part of the final liquidation of the trust. The amortized cost and estimated fair value of debt securities available for sale at December 31, 2015 , by contractual maturity, are shown below: Amortized Estimated (dollars in thousands) Due within 1 year $ 2,601 $ 2,595 Due after 1 but within 5 years 16,600 16,523 Due after 5 but within 10 years 27,066 27,598 Due after 10 years 44,136 37,977 90,403 84,693 Mortgage-Backed Securities (a) 798,538 799,697 Total Debt Securities $ 888,941 $ 884,390 (a) Mortgage Backed Securities include an amortized cost of $20.0 million and a fair value of $22.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $778.5 million and a fair value of $777.6 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac. Proceeds from sales, gross gains (losses) realized on sales, maturities and other-than-temporary impairment charges related to securities available for sale were as follows for the years ended December 31 : 2015 2014 2013 (dollars in thousands) Proceeds from sales $ 88,054 $ 132,868 $ 671 Gross (losses) gains realized: Sales Transactions: Gross gains $ — $ 291 $ 233 Gross losses (284 ) (243 ) — (284 ) 48 233 Maturities and impairment Gross gains 131 502 4 Gross losses — — (1,395 ) Other-than-temporary impairment — — — 131 502 (1,391 ) Net gains and impairment $ (153 ) $ 550 $ (1,158 ) Securities available for sale with an approximate fair value of $416.1 million and $563.2 million were pledged as of December 31, 2015 and 2014 , 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, 2015 . There were no held to maturity securities at December 31, 2014 . December 31, 2015 Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 4,775 $ — $ (7 ) $ 4,768 Mortgage-Backed Securities – Commercial 16,843 — (247 ) 16,596 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 315,609 30 (1,824 ) 313,815 Mortgage-Backed Securities – Commercial 15,187 — (178 ) 15,009 Obligations of States and Political Subdivisions 31,910 301 (58 ) 32,153 Total Securities Held to Maturity $ 384,324 $ 331 $ (2,314 ) $ 382,341 The amortized cost and estimated fair value of debt securities held to maturity at December 31, 2015 , 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 $ — $ — Due after 1 but within 5 years 108 108 Due after 5 but within 10 years 27,224 27,487 Due after 10 years 4,578 4,558 31,910 32,153 Mortgage-Backed Securities (a) 352,414 350,188 Total Debt Securities $ 384,324 $ 382,341 (a) Mortgage Backed Securities include an amortized cost of $21.6 million and a fair value of $21.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $330.8 million and a fair value of $328.8 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 $45.7 million were pledged as of December 31, 2015 to secure public deposits for other purposes required or permitted by law.

Impairment of Investment Securi

Impairment of Investment Securities	12 Months Ended
	Dec. 31, 2015
Impairment of Investment Securities Disclosure [Abstract]
Impairment of Investment Securities	Impairment of Investment Securities Securities Available for Sale As required by FASB ASC Topic 320, “Investments—Debt and Equity Securities,” credit related other-than-temporary impairment on debt securities is recognized in earnings while non-credit related other-than-temporary impairment on debt securities not expected to be sold is recognized in other comprehensive income (“OCI”). During the years ended December 31, 2015 , 2014 and 2013 , 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. This review includes analyzing the length of time and the extent to which the fair value has been lower than the cost, 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. In addition, the risk of future other-than-temporary impairment may be influenced by additional bank failures, weakness in the U.S. economy, changes in real estate values and additional interest deferrals in our pooled trust preferred collateralized debt obligations. Our pooled trust preferred collateralized debt obligations are beneficial interests in securitized financial assets within the scope of FASB ASC Topic 325, “Investments—Other,” and are therefore evaluated for other-than-temporary impairment using management’s best estimate of future cash flows. If these estimated cash flows determine it is probable that an adverse change in cash flows has occurred, then other-than-temporary impairment would be recognized in accordance with FASB ASC Topic 320. There is a risk that First Commonwealth will record other-than-temporary impairment charges in the future. See Note 18, “Fair Values of Assets and Liabilities,” for additional information. The following table presents the gross unrealized losses and estimated fair values at December 31, 2015 for both available for sale 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 Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 6,798 $ (20 ) $ — $ — $ 6,798 $ (20 ) Mortgage-Backed Securities – Commercial 16,596 (247 ) — — 16,596 (247 ) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 436,011 (3,293 ) 263,119 (7,413 ) 699,130 (10,706 ) Mortgage-Backed Securities – Commercial 15,009 (178 ) — — 15,009 (178 ) Other Government-Sponsored Enterprises 12,316 (85 ) — — 12,316 (85 ) Obligations of States and Political Subdivisions 7,208 (58 ) — — 7,208 (58 ) Pooled Trust Preferred Collateralized Debt Obligations — — 29,957 (7,497 ) 29,957 (7,497 ) Total Securities $ 493,938 $ (3,881 ) $ 293,076 $ (14,910 ) $ 787,014 $ (18,791 ) At December 31, 2015 , pooled trust preferred collateralized debt obligations accounted for 40% of unrealized losses due to changes in interest rates and the illiquid market for this type of investment. Fixed income securities issued by U.S. Government-sponsored enterprises comprised 59% of total unrealized losses due to changes in market interest rates. Obligations of state and political subdivisions account for the remaining 1% of total unrealized losses as a result of changes in market interest rates. At December 31, 2015 , there were 80 debt securities in an unrealized loss position. There were no equity securities in an unrealized loss position at December 31, 2015 . The following table presents the gross unrealized losses and estimated fair value at December 31, 2014 for available-for-sale and 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 Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 2,318 $ (3 ) $ — $ — $ 2,318 $ (3 ) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 111,646 (419 ) 368,706 (9,411 ) 480,352 (9,830 ) Other Government-Sponsored Enterprises 112,473 (229 ) 130,401 (1,079 ) 242,874 (1,308 ) Obligations of States and Political Subdivisions 3,146 (43 ) — — 3,146 (43 ) Pooled Trust Preferred Collateralized Debt Obligations — — 24,356 (13,236 ) 24,356 (13,236 ) Total Securities $ 229,583 $ (694 ) $ 523,463 $ (23,726 ) $ 753,046 $ (24,420 ) As of December 31, 2015 , our corporate securities had an amortized cost and estimated fair value of $1.9 million and $2.3 million , respectively, and were comprised of single issue trust preferred securities issued primarily by money center and large regional banks. At December 31, 2014 , these securities had an amortized cost of $6.7 million and estimated fair value of $7.3 million . There were no corporate securities in an unrealized loss position as of December 31, 2015 and 2014 . When unrealized losses exist, management reviews each of the issuer’s asset quality, earnings trend and capital position, to determine whether issues in an unrealized loss position were other-than-temporarily impaired. All interest payments on the corporate securities are being made as contractually required. As of December 31, 2015 , the book value of our pooled trust preferred collateralized debt obligations totaled $42.2 million with an estimated fair value of $35.7 million , which includes securities comprised of 275 banks and other financial institutions. All of our pooled securities are mezzanine tranches, three of which have no senior class remaining in the issue. The credit ratings on all of the issues are below investment grade. At the time of initial issue, the subordinated tranches ranged in size from approximately 7% to 35% of the total principal amount of the respective securities and no more than 5% of any pooled security consisted of a security issued by any one institution. As of December 31, 2015 , after taking into account management’s best estimates of future interest deferrals and defaults, four of our securities had no excess subordination in the tranches we own and five of our securities had excess subordination which ranged from 10% to 84% of the current performing collateral. The following table provides additional information related to our pooled trust preferred collateralized debt obligations as of December 31, 2015 : Deal Class Book Estimated Fair Unrealized Moody’s/ Number Deferrals Excess (dollars in thousands) Pre TSL IV Mezzanine $ 1,830 $ 1,336 $ (494 ) B1/BB 6 18.05 % 59.91 % Pre TSL VII Mezzanine 2,963 3,484 521 Ca/- 14 49.68 0.00 Pre TSL VIII Mezzanine 2,000 1,863 (137 ) C/C 29 56.74 0.00 Pre TSL IX Mezzanine 2,376 1,805 (571 ) B1/C 38 29.80 9.90 Pre TSL X Mezzanine 1,613 1,915 302 Caa1/C 43 30.66 0.00 Pre TSL XII Mezzanine 5,688 4,585 (1,103 ) B3/C 66 23.07 0.00 Pre TSL XIII Mezzanine 12,706 10,660 (2,046 ) Ba3/C 56 11.08 37.45 Pre TSL XIV Mezzanine 12,854 9,708 (3,146 ) B1/CC 56 19.72 47.01 MMCap I Mezzanine 209 302 93 Ca/C 8 58.11 83.61 Total $ 42,239 $ 35,658 $ (6,581 ) Lack of liquidity in the market for trust preferred collateralized debt obligations, below investment grade credit rating and market uncertainties related to the financial industry are factors contributing to the impairment on these securities. All of the Company's pooled trust preferred securities are included in the non-exclusive list issued by the regulatory agencies and therefore are not considered covered funds under the Volcker Rule. On a quarterly basis we evaluate our debt securities for other-than-temporary impairment. For the years ended December 31, 2015 , 2014 and 2013 there were no credit related other-than-temporary impairment charges recognized on our pooled trust preferred collateralized debt obligations. When evaluating these investments we determine a credit related portion and a non-credit related portion of other-than-temporary impairment. The credit related portion is recognized in earnings and represents the difference between book value and the present value of future cash flows. The non-credit related portion is recognized in OCI and represents the difference between the fair value of the security and the amount of credit related impairment. A discounted cash flow analysis provides the best estimate of credit related other-than-temporary impairment for these securities. Additional information related to the discounted cash flow analysis follows: Our pooled trust preferred collateralized debt obligations are measured for other-than-temporary impairment within the scope of FASB ASC Topic 325 by determining whether it is probable that an adverse change in estimated cash flows has occurred. Determining whether there has been an adverse change in estimated cash flows from the cash flows previously projected involves comparing the present value of remaining cash flows previously projected against the present value of the cash flows estimated at December 31, 2015 . We consider the discounted cash flow analysis to be our primary evidence when determining whether credit related other-than-temporary impairment exists. Results of a discounted cash flow test are significantly affected by other variables such as the estimate of future cash flows, credit worthiness of the underlying banks and determination of probability of default of the underlying collateral. The following provides additional information for each of these variables: • Estimate of Future Cash Flows—Cash flows are constructed in an INTEX cash flow model which includes each deal’s structural features. Projected cash flows include prepayment assumptions, which are dependent on the issuer's asset size and coupon rate. For collateral issued by financial institutions over $15 billion in asset size with a coupon over 7% , a 100% prepayment rate is assumed. Financial institutions over $15 billion with a coupon of 7% or under are assigned a prepayment rate of 40% for two years and 2% thereafter. Financial institutions with assets between $2 billion and $15 billion with coupons over 7% are assigned a 5% prepayment rate. For financial institutions below $2 billion , if the coupon is over 10% , a prepayment rate of 5% is assumed and for all other issuers, there is no prepayment assumption incorporated into the cash flows. The modeled cash flows are then used to estimate if all the scheduled principal and interest payments of our investments will be returned. • Credit Analysis—A quarterly credit evaluation is performed for each of the 275 banks comprising the collateral across the various pooled trust preferred securities. Our credit evaluation considers all evidence available to us and includes the nature of the issuer’s business, its years of operating history, corporate structure, loan composition, loan concentrations, deposit mix, asset growth rates, geographic footprint and local economic environment. Our analysis focuses on profitability, return on assets, shareholders’ equity, net interest margin, credit quality ratios, operating efficiency, capital adequacy and liquidity. • Probability of Default—A probability of default is determined for each bank and is used to calculate the expected impact of future deferrals and defaults on our expected cash flows. Each bank in the collateral pool is assigned a probability of default for each year until maturity. Currently, any bank that is in default is assigned a 100% probability of default and a 0% projected recovery rate. All other banks in the pool are assigned a probability of default based on their unique credit characteristics and market indicators with a 10% projected recovery rate. For the majority of banks currently in deferral we assume the bank continues to defer and will eventually default and therefore a 100% probability of default is assigned. However, for some deferring collateral there is the possibility that they become current on interest or principal payments at some point in the future and in those cases a probability that the deferral will ultimately cure is assigned. The probability of default is updated quarterly. As of December 31, 2015 , default probabilities for performing collateral ranged from 0.33% to 75% . Our credit evaluation provides a basis for determining deferral and default probabilities for each underlying piece of collateral. Using the results of the credit evaluation, the next step of the process is to look at pricing of senior debt or credit default swaps for the issuer (or where such information is unavailable, for companies having similar credit profiles as the issuer). The pricing of these market indicators provides the information necessary to determine appropriate default probabilities for each bank. In addition to the above factors, our evaluation of impairment also includes a stress test analysis which provides an estimate of excess subordination for each tranche. We stress the cash flows of each pool by increasing current default assumptions to the level of defaults which results in an adverse change in estimated cash flows. This stressed breakpoint is then used to calculate excess subordination levels for each pooled trust preferred security. The results of the stress test allows management to identify those pools that are at a greater risk for a future break in cash flows so that we can monitor banks in those pools more closely for potential deterioration of credit quality. Our cash flow analysis as of December 31, 2015 , indicates that no credit related other-than-temporary impairment has occurred on our pooled trust preferred securities during the year ended December 31, 2015 . Based upon the analysis performed by management, it is probable that four of our pooled trust preferred securities are expected to experience contractual principal and interest shortfalls and therefore appropriate other-than-temporary impairment charges were recorded in prior periods. These securities are identified in the table on page 68 with 0% “Excess Subordination as a % of Current Performing Collateral.” For the remaining securities in the table, our analysis as of December 31, 2015 indicates that it is probable that we will collect all contractual principal and interest payments. For four of those securities, PreTSL IX, PreTSL XIII, PreTSL XIV and MMCap I, other-than-temporary impairment charges were recorded in prior periods; however, due to improvement in the expected cash flows of these securities, it is now probable that all contractual payments will be received. During 2008, 2009 and 2010, other-than-temporary impairment charges were recognized on all of our pooled trust preferred securities, except for PreTSL IV. Our cash flow analysis as of December 31, 2015 , for all of these impaired securities indicates that it is now probable we will collect principal and interest in excess of what was estimated at the time other-than-temporary impairment charges were recorded. This change can be attributed to improvement in the underlying collateral for these securities and has resulted in the present value of estimated future principal and interest payments exceeding the securities' current book value. The excess for each bond of the present value of future cash flows over our current book value ranges from 20% to 133% and will be recognized as an adjustment to yield over the remaining life of these securities. The excess subordination recognized as an adjustment to yield is reflected in the following table as increases in cash flows expected to be collected. The table below provides a cumulative roll forward of credit losses recognized in earnings for debt securities held and not intended to be sold for the years ended December 31: 2015 2014 2013 (dollars in thousands) Balance, beginning (a) $ 26,246 $ 27,543 $ 43,274 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 security (b) (1,177 ) (1,297 ) (2,375 ) Reduction for debt securities called during the period (218 ) — (13,356 ) Balance, ending $ 24,851 $ 26,246 $ 27,543 (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. For the years ended December 31, 2015 , 2014 and 2013 , there was no impairment recognized on equity securities. On a quarterly basis, management evaluates equity securities for other-than-temporary impairment. As part of this evaluation we review the severity and duration of decline in estimated fair value, research reports, analysts’ recommendations, credit rating changes, news stories, annual reports, regulatory filings, impact of interest rate changes and other relevant information. There were no equity securities in an unrealized loss position as of December 31, 2015 and 2014 . In the table above, the $13.4 million reduction in cumulative credit losses in 2013 related to debt securities being called is a result of the early redemption of MMComm IX. The senior note holders of this bond elected to liquidate all assets of the trust, resulting in losses for the mezzanine notes owned by First Commonwealth. Our book value before redemption was $6.6 million and at the time of redemption a loss of $1.3 million was recognized. Other Investments As a member of the 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, 2015 and 2014 , our FHLB stock totaled $63.0 million and $44.5 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, 2015 .

Loans and Allowance for Credit

Loans and Allowance for Credit Losses	12 Months Ended
	Dec. 31, 2015
Loans and Leases Receivable Disclosure [Abstract]
Loans and Allowance for Credit Losses	Loans and Allowance for Credit Losses The following table provides outstanding balances related to each of our loan types as of December 31 : 2015 2014 (dollars in thousands) Commercial, financial, agricultural and other $ 1,150,906 $ 1,052,109 Real estate construction 220,736 120,785 Residential real estate 1,224,465 1,226,344 Commercial real estate 1,479,000 1,405,256 Loans to individuals 608,643 652,814 Total loans and leases net of unearned income $ 4,683,750 $ 4,457,308 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 loans: Pass Acceptable levels of risk exist in the relationship. Includes all loans not adversely 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 use of creditworthiness categories to grade loans permits management’s use of migration analysis to estimate a portion of credit risk. 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. Movements between these rating categories provide a predictive measure of credit losses and therefore assists in determining the appropriate level for the loan loss reserves. 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. Loans that migrate towards higher risk rating levels generally have an increased risk of default, whereas loans that migrate toward lower risk ratings generally will result in a lower risk factor being applied to those related loan balances. The following tables represent our credit risk profile by creditworthiness category for the years ended December 31 : 2015 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 1,074,858 $ 220,267 $ 1,209,606 $ 1,436,714 $ 608,342 $ 4,549,787 Non-Pass OAEM 11,825 442 5,244 30,012 — 47,523 Substandard 64,223 27 9,615 12,274 301 86,440 Doubtful — — — — — — Total Non-Pass 76,048 469 14,859 42,286 301 133,963 Total $ 1,150,906 $ 220,736 $ 1,224,465 $ 1,479,000 $ 608,643 $ 4,683,750 2014 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 983,357 $ 112,536 $ 1,214,920 $ 1,353,773 $ 652,596 $ 4,317,182 Non-Pass OAEM 32,563 8,013 2,315 29,479 — 72,370 Substandard 32,028 236 9,109 22,004 218 63,595 Doubtful 4,161 — — — — 4,161 Total Non-Pass 68,752 8,249 11,424 51,483 218 140,126 Total $ 1,052,109 $ 120,785 $ 1,226,344 $ 1,405,256 $ 652,814 $ 4,457,308 The change in the amount of OAEM and Substandard loans at December 31, 2015 compared to December 31, 2014 is primarily the result of two commercial industrial borrowers that migrated from OAEM to non-accrual status during 2015. Additional details on these loans are provided on page 75. Portfolio Risks The credit quality of our loan portfolio can potentially represent significant risk to our earnings, capital, regulatory agency relationships, investment community and shareholder returns. 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 activities. 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, 2015 and 2014 were $18.9 million and $17.5 million , respectively. Criticized loans have been evaluated when determining the appropriateness of the allowance for credit losses, which we believe is adequate to absorb losses inherent to the portfolio as of December 31, 2015 . However, changes in economic conditions, interest rates, borrower financial condition, delinquency trends or previously established fair values of collateral factors could significantly change those judgmental estimates. 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. 2015 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 364 $ 49 $ 129 $ 23,653 $ 24,195 $ 1,126,711 $ 1,150,906 Real estate construction 280 — — 28 308 220,428 220,736 Residential real estate 4,175 1,055 1,315 6,500 13,045 1,211,420 1,224,465 Commercial real estate 781 — 65 6,223 7,069 1,471,931 1,479,000 Loans to individuals 2,998 774 946 301 5,019 603,624 608,643 Total $ 8,598 $ 1,878 $ 2,455 $ 36,705 $ 49,636 $ 4,634,114 $ 4,683,750 2014 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 2,816 $ 213 $ 264 $ 27,007 $ 30,300 $ 1,021,809 $ 1,052,109 Real estate construction — 1 — 236 237 120,548 120,785 Residential real estate 5,162 1,295 1,077 7,900 15,434 1,210,910 1,226,344 Commercial real estate 1,797 122 — 7,306 9,225 1,396,031 1,405,256 Loans to individuals 3,698 1,059 1,278 218 6,253 646,561 652,814 Total $ 13,473 $ 2,690 $ 2,619 $ 42,667 $ 61,449 $ 4,395,859 $ 4,457,308 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 doubtful. Impaired Loans Management considers loans to be impaired 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. Determination of impairment is treated the same across all loan categories. When management identifies a loan as impaired, the impairment 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 impaired loan is less than the recorded investment in the loan, impairment is recognized through an allowance estimate or a charge-off to the allowance. Troubled debt restructured loans on accrual status are considered to be impaired loans. When the ultimate collectability of the total principal of an impaired 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 an impaired 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 were no impaired loans held for sale at December 31, 2015 and December 31, 2014 ; sales of impaired loans during the years ended December 31, 2015 and 2014 resulted in gains of $0.4 million and $77 thousand , respectively. Significant nonaccrual loans as of December 31, 2015 , included the following: • A $7.5 million relationship of commercial industrial loans to an oil and gas well services company. These loans were originated in 2014 and were placed in nonaccrual status during the fourth quarter of 2015. All collateral valuations were completed in June or November of 2015. • A $5.6 million relationship of commercial industrial loans to a local energy company. These loans were originated from 2008 to 2011 and were placed in nonaccrual status during the third quarter of 2013. Two of these loans were modified resulting in TDR classification: one loan totaling $2.3 million was modified in 2012, and the other loan totaling $2.9 million was modified in 2014. During the year ended December 31, 2015 , chargeoffs of $3.3 million related to this relationship were recorded. A gas reserve study was obtained in March 2015 and was internally updated in December 2015 for adjustments to the pricing forecast and production estimates. All other collateral was valued in November 2015. • A $3.9 million relationship of commercial industrial loans to an industrial manufacturer. These loans were originated in 2013 and were placed in nonaccrual status during the third quarter of 2015. Charge-offs of $2.0 million related to this relationship were recognized during the fourth quarter of 2015. A valuation of the collateral was completed during the fourth quarter of 2015. • A $3.9 million relationship of commercial industrial loans to a manufacturer of sporting goods. These loans were originated from 2012 to 2015 and were placed in nonaccrual status during the fourth quarter of 2015. A valuation of the collateral was completed during the fourth quarter of 2015. The following tables include the recorded investment and unpaid principal balance for impaired loans with the associated allowance amount, if applicable, as of December 31, 2015 and 2014 . Also presented are the average recorded investment in impaired loans and the related amount of interest recognized while the loan was considered impaired for the years ended December 31, 2015 , 2014 and 2013 . 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. 2015 Recorded Unpaid Related Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 11,344 $ 15,673 $ 17,692 $ 216 Real estate construction 28 117 95 — Residential real estate 9,952 11,819 10,635 172 Commercial real estate 7,562 9,449 7,890 90 Loans to individuals 421 507 338 4 Subtotal 29,307 37,565 36,650 482 With an allowance recorded: Commercial, financial, agricultural and other 20,132 22,590 $ 6,952 7,731 129 Real estate construction — — — — — Residential real estate 461 672 51 403 — Commercial real estate 944 1,008 42 674 4 Loans to individuals — — — — — Subtotal 21,537 24,270 7,045 8,808 133 Total $ 50,844 $ 61,835 $ 7,045 $ 45,458 $ 615 2014 Recorded Unpaid Related Average Interest With no related allowance recorded: Commercial, financial, agricultural and other $ 9,439 $ 10,937 $ 11,536 $ 133 Real estate construction 236 476 1,190 19 Residential real estate 10,773 12,470 11,592 210 Commercial real estate 8,768 10,178 8,830 98 Loans to individuals 288 337 308 4 Subtotal 29,504 34,398 33,456 464 With an allowance recorded: Commercial, financial, agricultural and other 24,826 25,583 $ 9,304 15,797 143 Real estate construction — — — — — Residential real estate 367 380 56 357 14 Commercial real estate 554 554 101 184 4 Loans to individuals — — — — — Subtotal 25,747 26,517 9,461 16,338 161 Total $ 55,251 $ 60,915 $ 9,461 $ 49,794 $ 625 2013 Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 14,454 $ 73 Real estate construction 5,923 47 Residential real estate 9,280 211 Commercial real estate 27,881 250 Loans to individuals 255 3 Subtotal 57,793 584 With an allowance recorded: Commercial, financial, agricultural and other 16,479 64 Real estate construction 515 — Residential real estate 3,200 31 Commercial real estate 188 — Loans to individuals — — Subtotal 20,382 95 Total $ 78,175 $ 679 Unfunded commitments related to nonperforming loans were $0.1 million and $46 thousand at December 31, 2015 and 2014 , respectively. After consideration of available collateral related to these commitments, a reserve of $13 thousand and $14 thousand was established for these off balance sheet exposures at December 31, 2015 and 2014 , 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. 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 : 2015 2014 2013 (dollars in thousands) Troubled debt restructured loans Accrual status $ 14,139 $ 12,584 $ 13,495 Nonaccrual status 12,360 16,952 16,980 Total $ 26,499 $ 29,536 $ 30,475 Commitments Unused lines of credit 3,252 4,120 452 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 : 2015 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 12 $ 1,751 $ 3,195 $ 4,527 $ 9,473 $ 8,823 $ 1,330 Residential real estate 32 — 296 1,414 1,710 1,575 2 Commercial real estate 1 — — 464 464 389 — Loans to individuals 16 3 167 35 205 169 — Total 61 $ 1,754 $ 3,658 $ 6,440 $ 11,852 $ 10,956 $ 1,332 2014 Type of Modification Number Extend Modify Modify Other Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 9 $ 5,487 $ — $ 14,529 $ — $ 20,016 $ 13,785 $ 4,665 Residential real estate 52 — 629 1,797 — 2,426 2,062 — Commercial real estate 1 — — 8 — 8 6 — Loans to individuals 15 — 103 47 — 150 114 — Total 77 $ 5,487 $ 732 $ 16,381 $ — $ 22,600 $ 15,967 $ 4,665 2013 Type of Modification Number Extend Modify Modify Other Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 14 $ 3,462 $ — $ 1,677 $ — $ 5,139 $ 3,104 $ 906 Residential real estate 46 347 418 2,116 — 2,881 2,316 161 Commercial real estate 5 571 1,499 145 — 2,215 2,184 34 Loans to individuals 17 10 101 33 — 144 109 — Total 82 $ 4,390 $ 2,018 $ 3,971 $ — $ 10,379 $ 7,713 $ 1,101 The troubled debt restructurings included in the above tables are also included in the impaired 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, 2015 , 2014 and 2013 , $3.7 million , $0.6 million and $2.0 million , respectively, of total rate modifications represent loans with modifications to the rate as well as payment due to reamortization. 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 restructured loans that were considered to be in default during the as of December 31 : 2015 2014 2013 Number of Recorded Number of Recorded Number of Recorded (dollars in thousands) Residential real estate 3 $ 97 2 $ 7 1 $ 19 Commercial real estate — — 1 6 — — Total 3 $ 97 3 $ 13 1 $ 19 The following tables provide detail related to the allowance for credit losses for the years ended December 31 . During 2013, the negative $5.9 million provision for credit losses related to the unallocated portion of the allowance is a result of it no longer being treated as a separate component of the allowance but instead is now incorporated into the reserve provided for each loan category. This portion of the allowance for credit losses reflects the qualitative or environmental factors that are likely to cause estimated credit losses to differ from historical loss experience. 2015 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 29,627 $ 2,063 $ 3,664 $ 11,881 $ 4,816 $ 52,051 Charge-offs (11,429 ) (8 ) (1,539 ) (1,538 ) (4,354 ) (18,868 ) Recoveries 1,097 84 587 229 684 2,681 Provision (credit) 11,740 (1,252 ) (106 ) 1,352 3,214 14,948 Ending Balance $ 31,035 $ 887 $ 2,606 $ 11,924 $ 4,360 $ 50,812 Ending balance: individually evaluated for impairment $ 6,952 $ — $ 51 $ 42 $ — $ 7,045 Ending balance: collectively evaluated for impairment 24,083 887 2,555 11,882 4,360 43,767 Loans: Ending balance 1,150,906 220,736 1,224,465 1,479,000 608,643 4,683,750 Ending balance: individually evaluated for impairment 30,767 — 6,099 7,143 — 44,009 Ending balance: collectively evaluated for impairment 1,120,139 220,736 1,218,366 1,471,857 608,643 4,639,741 2014 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 22,663 $ 6,600 $ 7,727 $ 11,778 $ 5,457 $ 54,225 Charge-offs (8,911 ) (296 ) (3,153 ) (1,148 ) (3,964 ) (17,472 ) Recoveries 734 1,340 650 612 766 4,102 Provision (credit) 15,141 (5,581 ) (1,560 ) 639 2,557 11,196 Ending Balance $ 29,627 $ 2,063 $ 3,664 $ 11,881 $ 4,816 $ 52,051 Ending balance: individually evaluated for impairment $ 9,304 $ — $ 56 $ 101 $ — $ 9,461 Ending balance: collectively evaluated for impairment 20,323 2,063 3,608 11,780 4,816 42,590 Loans: Ending balance 1,052,109 120,785 1,226,344 1,405,256 652,814 4,457,308 Ending balance: individually evaluated for impairment 33,332 193 7,127 7,790 — 48,442 Ending balance: collectively evaluated for impairment 1,018,777 120,592 1,219,217 1,397,466 652,814 4,408,866 2013 Commercial, Real estate Residential Commercial Loans to Unallocated Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 19,852 $ 8,928 $ 5,908 $ 22,441 $ 4,132 $ 5,926 $ 67,187 Charge-offs (18,399 ) (773 ) (1,814 ) (10,513 ) (3,679 ) — (35,178 ) Recoveries 455 501 1,264 136 633 — 2,989 Provision (credit) 20,755 (2,056 ) 2,369 (286 ) 4,371 (5,926 ) 19,227 Ending Balance $ 22,663 $ 6,600 $ 7,727 $ 11,778 $ 5,457 $ — $ 54,225 Ending balance: individually evaluated for impairment $ 7,364 $ 94 $ 1,282 $ 84 $ — $ — $ 8,824 Ending balance: collectively evaluated for impairment 15,299 6,506 6,445 11,694 5,457 — 45,401 Loans: Ending balance 1,021,056 93,289 1,262,718 1,296,472 610,298 4,283,833 Ending balance: individually evaluated for impairment 27,251 3,844 9,349 12,151 — 52,595 Ending balance: collectively evaluated for impairment 993,805 89,445 1,253,369 1,284,321 610,298 4,231,238

Commitments and Letters of Cred

Commitments and Letters of Credit	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014 , 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 : 2015 2014 (dollars in thousands) Financial instruments whose contract amounts represent credit risk: Commitments to extend credit $ 1,643,187 $ 1,635,948 Financial standby letters of credit 17,843 36,075 Performance standby letters of credit 26,497 25,915 Commercial letters of credit 1,672 2,611 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, 2015 include amounts issued in 2015 of $5.9 million in financial standby letters of credit and $2.6 million in performance standby letters of credit. There were no commercial letters of credit issued during 2015 . A liability of $0.2 million and $0.2 million has been recorded as of December 31, 2015 and 2014 , respectively, 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 $4.4 million and $3.1 million as of December 31, 2015 and 2014 , respectively. This liability is reflected in “ Other liabilities ” in the Consolidated Statements of Financial Condition. The credit risk evaluation incorporated probability of default, loss given default and estimated utilization for the next twelve months for each loan category and the letters of credit.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Premises and equipment are described as follows: Estimated Useful Life 2015 2014 (dollars in thousands) Land Indefinite $ 12,185 $ 12,098 Buildings and improvements 10-50 years 77,086 75,873 Leasehold improvements 5-40 years 14,518 14,229 Furniture and equipment 3-10 years 59,463 59,034 Software 3-7 years 34,472 37,007 Subtotal 197,724 198,241 Less accumulated depreciation and amortization 134,270 133,252 Total premises and equipment $ 63,454 $ 64,989 Depreciation related to premises and equipment included in noninterest expense for the years ended December 31, 2015 , 2014 and 2013 amounted to $7.2 million , $13.2 million and $10.4 million , respectively. First Commonwealth leases various premises and assorted equipment under non-cancellable agreements. Total future minimal rental commitments at December 31, 2015 , were as follows: Premises Equipment (dollars in thousands) 2016 $ 3,339 $ 66 2017 3,004 53 2018 2,809 9 2019 2,531 — 2020 1,981 — Thereafter 10,360 — Total $ 24,024 $ 128 Included in the lease commitments above is $262 thousand in lease payments to be paid under a sale-leaseback arrangement. The sale-leaseback transaction occurred in 2005 and resulted in a gain of $297 thousand on the sale of a branch that is being recognized over the 15 year lease term through 2020. Increases in utilities and taxes that may be passed on to the lessee under the terms of various lease agreements are not reflected in the above table. However, certain lease agreements provide for increases in rental payments based upon historical increases in the consumer price index or the lessor’s cost of operating the facility, and are included in the minimum lease commitments. Additionally, the table above includes rent expense that is recognized for rent holidays and during construction periods. Total lease expense amounted to $2.9 million , $2.9 million and $4.2 million in 2015 , 2014 and 2013 , respectively.

Goodwill and Other Amortizing I

Goodwill and Other Amortizing Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill Disclosure [Abstract]
Goodwill and Other Amortizing Intangible Assets	Goodwill and Other Amortizing 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 triggering events or circumstances indicate goodwill testing is required, an assessment of qualitative factors can be completed before performing the two step goodwill impairment test. ASU 2011-8 provides that if an assessment of qualitative factors determines it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, then the two step goodwill impairment test is not required. We consider First Commonwealth to be one reporting unit. The carrying amount of goodwill as of December 31, 2015 and 2014 was $164.5 million and $161.4 million , respectively. The $3.1 million increase in goodwill during the year ended December 31, 2015 is due to the First Community Bank acquisition. No impairment charges on goodwill or other intangible assets were incurred in 2015 , 2014 or 2013 . 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. An assessment of qualitative factors was completed as of November 30, 2015 and December 31, 2015 and indicated that it is more likely than not that the fair value of First Commonwealth's goodwill exceeds its carrying amount; therefore, the two step goodwill impairment test was not considered necessary. The assessment of qualitative factors considered historical and projected financial performance, macroeconomic factors such as the Company's access to capital, the general business climate and changes in the banking industry as well as market considerations such as geographic expansion, new product offerings and the regulatory environment. As of December 31, 2015 , goodwill was not considered impaired; however, changing economic conditions that may adversely affect our performance, the fair value of our assets and liabilities, 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, which for each year includes only core deposit intangibles: Gross Intangible Assets Accumulated Amortization Net Intangible Assets (dollars in thousands) December 31, 2015 Customer deposit intangibles $ 19,142 $ (18,619 ) $ 523 Customer list intangible $ 984 $ (276 ) $ 708 Total other intangible assets $ 20,126 $ (18,895 ) $ 1,231 December 31, 2014 Customer deposit intangibles $ 22,470 $ (21,773 ) $ 697 Customer list intangible $ 984 $ (16 ) $ 968 Total other intangible assets $ 23,454 $ (21,789 ) $ 1,665 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 9.8 years and a weighted average amortization period of approximately 5.1 years. In the table above, the change in the gross customer deposit intangible from December 31, 2014 to December 31, 2015 is a result of 2015 being the final year of amortization on $3.5 million from prior acquisitions and the addition of $0.2 million from the First Community Bank acquisition. The customer list intangible represents the estimated value of the customer base for an insurance agency acquired in 2014. 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 and a weighted average amortization period of 13.8 years. First Commonwealth recognized amortization expense on other intangible assets of $0.6 million , $0.6 million , and $1.1 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. The following presents the estimated amortization expense of core deposit intangibles and the customer intangible list: Core Deposit Intangibles Customer Intangible List Total (dollars in thousands) 2016 $ 207 $ 168 $ 375 2017 90 130 220 2018 87 99 186 2019 78 77 155 2020 18 59 77 Thereafter 43 175 218 Total $ 523 $ 708 $ 1,231

Interest-Bearing Deposits

Interest-Bearing Deposits	12 Months Ended
	Dec. 31, 2015
Deposits [Abstract]
Interest-Bearing Deposits	Interest-Bearing Deposits Components of interest-bearing deposits at December 31 were as follows: 2015 2014 (dollars in thousands) Interest-bearing demand deposits $ 86,365 $ 81,851 Savings deposits 2,390,607 2,402,288 Time deposits 602,233 842,345 Total interest-bearing deposits $ 3,079,205 $ 3,326,484 Interest-bearing deposits at December 31, 2015 and 2014 , include allocations from interest-bearing demand deposit accounts of $580.8 million and $427.7 million , respectively, into savings which includes money market accounts. These reallocations are based on a formula and have been made to reduce First Commonwealth’s reserve requirement in compliance with regulatory guidelines. Included in time deposits at December 31, 2015 and 2014 , were certificates of deposit in denominations of $100 thousand or more of $157.7 million and $334.0 million , respectively. Interest expense related to certificates of deposit in denominations of $100 thousand or greater amounted to $1.8 million in 2015 , $3.7 million in 2014 and $4.7 million in 2013 . Included in time deposits at December 31, 2015 , were certificates of deposit with the following scheduled maturities (dollars in thousands): 2016 $ 354,324 2017 113,391 2018 45,744 2019 54,276 2020 and thereafter 34,498 Total $ 602,233

Short-term Borrowings

Short-term Borrowings	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
Short-term Borrowings	Short-term Borrowings Short-term borrowings at December 31 were as follows: 2015 2014 2013 Ending Average Average Ending Average Average Ending Average Average (dollars in thousands) Federal funds purchased $ 4,000 $ 14,832 0.36 % $ 9,000 $ 11,691 0.36 % $ 16,000 $ 11,982 0.36 % Borrowings from FHLB 1,400,000 1,117,522 0.42 945,000 644,651 0.31 478,100 335,449 0.27 Securities sold under agreements to repurchase 106,825 120,177 0.23 151,876 159,051 0.24 132,515 130,957 0.25 Total $ 1,510,825 $ 1,252,531 0.40 $ 1,105,876 $ 815,393 0.30 $ 626,615 $ 478,388 0.26 Maximum total at any month-end $ 1,510,825 $ 1,105,876 $ 626,615 Weighted average rate at year-end 0.53 % 0.30 % 0.27 % Interest expense on short-term borrowings for the years ended December 31 is detailed below: 2015 2014 2013 (dollars in thousands) Federal funds purchased $ 54 $ 42 $ 43 Borrowings from FHLB 4,684 2,019 893 Securities sold under agreements to repurchase 280 388 326 Total interest on short-term borrowings $ 5,018 $ 2,449 $ 1,262

Subordinated Debentures

Subordinated Debentures	12 Months Ended
	Dec. 31, 2015
Disclosure Subordinated Debentures [Abstract]
Subordinated Debentures	Subordinated Debentures Subordinated Debentures outstanding at December 31 are as follows: 2015 2014 Due Amount Rate Amount Rate (dollars in thousands) Owed to: First Commonwealth Capital Trust II 2034 $ 30,929 LIBOR + 2.85 $ 30,929 LIBOR + 2.85 First Commonwealth Capital Trust III 2034 41,238 LIBOR + 2.85 41,238 LIBOR + 2.85 Total $ 72,167 $ 72,167 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, 2015
Debt Disclosure [Abstract]
Other Long-term Debt	Other Long-term Debt Other long-term debt at December 31 follows: 2015 2014 Amount Weighted Weighted Amount Weighted Weighted (dollars in thousands) Borrowings from FHLB due: 2015 $ 80,142 0.82 % 0.82 % 2016 $ 563 3.82 % 3.82 % 563 3.82 3.82 2017 585 3.83 3.83 585 3.83 3.83 2018 607 3.83 3.83 607 3.83 3.83 2019 631 3.83 3.83 631 3.84 3.84 2020 659 3.84 3.84 Thereafter 6,269 3.81 3.81 6,931 3.81 3.81 Total $ 9,314 $ 89,459 The weighted average contractual rate reflects the rate due to creditors. The weighted average effective rate of long-term debt in the schedule above includes the effect of purchase accounting valuation adjustments that were recorded in connection with prior business combinations. 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 16, “Subordinated Debentures.”

Fair Values of Assets and Liabi

Fair Values of Assets and Liabilities	12 Months Ended
	Dec. 31, 2015
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 1 securities include equity holdings comprised of publicly traded bank stocks which were priced using quoted market prices. • 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 includes Obligations of 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 (including interest rate swaps, interest rate caps and risk participation agreements), certain other real estate owned and certain impaired 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 recognized pricing service price 100% of the securities on an annual basis and a random sample of securities each quarter, 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 are comprised of FHLB stock whose estimated fair value is based on its par value. Additional information on FHLB stock is provided in Note 9, “Impairment of 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. 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 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 three months, Eurodollar futures contracts and swap rates from three years 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 2015 and 2014 , we have not realized any losses due to a counterparty's inability to pay any net uncollateralized position. 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 pooled trust preferred collateralized debt obligations, non-marketable equity investments, certain interest rate derivatives, certain impaired loans and certain other real estate. Our pooled trust preferred collateralized debt obligations are collateralized by the trust preferred securities of individual banks, thrifts and bank holding companies in the U.S. There has been little or no active trading in these securities since 2009; therefore it was more appropriate to determine estimated fair value using a discounted cash flow analysis. Detail on the process for determining the appropriate cash flows for this analysis is provided in Note 9 “Impairment of Investment Securities.” The discount rate applied to the cash flows is determined by evaluating the current market yields for comparable corporate and structured credit products along with an evaluation of the risks associated with the cash flows of the comparable security. Due to the fact that there is no active market for the pooled trust preferred collateralized debt obligations, one key reference point is the market yield for the single issue trust preferred securities issued by banks and thrifts for which there is more activity than for the pooled securities. Adjustments are then made to reflect the credit and structural differences between these two security types. Management validates the estimated fair value of the pooled trust preferred collateralized debt obligations by understanding the pricing methodology utilized by third party pricing services and monitoring the performance of the underlying collateral, discussing the discount rate, cash flow assumptions and general market trends with the specialized third party and by confirming changes in the underlying collateral to the trustee reports. Management’s monitoring of the underlying collateral includes deferrals of interest payments, payment defaults, cures of previously deferred interest payments, any regulatory filings or actions and general news related to the underlying collateral. Management also evaluates fair value changes compared to expectations based on changes in the interest rates used in determining the discount rate and general financial markets. The estimated fair value of the non-marketable equity 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 the credit quality of the underlying counterparties (loan customers). In 2013, we experienced a $0.9 million credit loss as a result of a counterparty's inability to pay the net uncollateralized position on an interest rate swap. The full amount of this credit loss was provided for in prior periods. 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 Pooled Trust Preferred Securities $ 35,658 Discounted Cash Flow Probability of default 0% - 100% (13.38%) Prepayment rates 0% - 73.28% (5.07%) Discount rates 5.25% - 12.00% (a) Equities 2,170 Par Value N/A N/A Impaired Loans 2,859 (b) Gas Reserve study Discount rate 10.00% Gas per MCF $2.34 - $3.71 (c) Oil per BBL/d $42.56 - $65.13 (c) 2,963 (b) Discounted Cash Flow Discount Rate 1.90% - 4.81% Other Real Estate Owned 8 Internal Valuation N/A N/A (a) incorporates spread over the risk free rate related primarily to credit quality and illiquidity of securities. (b) the remainder of impaired loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation. (c) unobservable inputs are defined as follows: MCF—million cubic feet; BBL/d—barrels per day. The significant unobservable inputs used in the fair value measurement of pooled trust preferred securities are the probability of default, discount rates and prepayment rates. Significant increases in the probability of default or discount rate used would result in a decrease in the estimated fair value of these securities, while decreases in these variables would result in higher fair value measurements. In general, a change in the assumption of probability of default is accompanied by a directionally similar change in the discount rate. In most cases, increases in the prepayment rate assumptions would result in a higher estimated fair value for these securities while decreases would provide for a lower value. The direction of this change is somewhat dependent on the structure of the investment and the amount of the investment tranches senior to our position. The discount rate is the significant unobservable input used in the fair value measurement of impaired 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 impaired loans relate to gas, oil and natural gas prices. Increases in these rates 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: 2015 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 22,092 $ — $ 22,092 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 777,577 — 777,577 Mortgage-Backed Securities—Commercial — 28 — 28 Other Government-Sponsored Enterprises — 19,118 — 19,118 Obligations of States and Political Subdivisions — 27,598 — 27,598 Corporate Securities — 2,319 — 2,319 Pooled Trust Preferred Collateralized Debt Obligations — — 35,658 35,658 Total Debt Securities — 848,732 35,658 884,390 Equities — — 2,170 2,170 Total Securities Available for Sale — 848,732 37,828 886,560 Other Investments — 62,952 — 62,952 Loans Held for Sale — 5,763 — 5,763 Other Assets (a) — 11,273 — 11,273 Total Assets $ — $ 928,720 $ 37,828 $ 966,548 Other Liabilities (a) $ — $ 10,829 $ — $ 10,829 Total Liabilities $ — $ 10,829 $ — $ 10,829 (a) Hedging and non-hedging interest rate derivatives 2014 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 25,936 $ — $ 25,936 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 950,881 — 950,881 Mortgage-Backed Securities—Commercial — 74 — 74 Other Government-Sponsored Enterprises — 267,877 — 267,877 Obligations of States and Political Subdivisions — 27,377 — 27,377 Corporate Securities — 7,255 — 7,255 Pooled Trust Preferred Collateralized Debt Obligations — — 28,999 28,999 Total Debt Securities — 1,279,400 28,999 1,308,399 Equities — — 1,420 1,420 Total Securities Available for Sale — 1,279,400 30,419 1,309,819 Other Investments — 44,545 — 44,545 Loans Held for Sale — 2,502 — 2,502 Other Assets (a) — 11,186 — 11,186 Total Assets $ — $ 1,337,633 $ 30,419 $ 1,368,052 Other Liabilities (a) $ — $ 10,671 $ — $ 10,671 Total Liabilities $ — $ 10,671 $ — $ 10,671 (a) Non-hedging interest rate derivatives 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, 2015 : Pooled Trust Equities Loans Total (dollars in thousands) Balance, beginning of year $ 28,999 $ 1,420 $ — $ 30,419 Total gains or losses Included in earnings 111 — — 111 Included in other comprehensive income 7,608 — — 7,608 Purchases, issuances, sales, and settlements Purchases — 750 — 750 Issuances — — — — Sales — — — — Settlements (1,060 ) — — (1,060 ) Transfers from Level 3 — — — — Transfers into Level 3 — — — — Balance, end of year $ 35,658 $ 2,170 $ — $ 37,828 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, 2015 . During the year ended December 31, 2015 , there were no transfers between fair value Levels 1 2, and 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, 2014 : Pooled Trust Equities Loans Other Total (dollars in thousands) Balance, beginning of year $ 23,523 $ 1,420 $ — $ — $ 24,943 Total gains or losses Included in earnings — — 77 — 77 Included in other comprehensive income 7,162 — — — 7,162 Purchases, issuances, sales, and settlements Purchases — — — — — Issuances — — — — — Sales — — (3,112 ) — (3,112 ) Settlements (1,686 ) — — — (1,686 ) Transfers from Level 3 — — — — — Transfers into Level 3 — — 3,035 — 3,035 Balance, end of year $ 28,999 $ 1,420 $ — $ — $ 30,419 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, 2014 . During 2014 , there were no transfers between fair value Levels 1 and 2. However, $3.0 million of loans were transferred into Level 3 from Level 2 due to the loans being transferred to a held for sale status. The loans transferred and subsequently sold related to three nonperforming relationships for which this was determined to be an appropriate exit strategy. Completion of the loan sales resulted in a $0.1 million gain for the period. 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: 2015 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Impaired loans $ — $ 30,979 $ 12,820 $ 43,799 $ (9,098 ) Other real estate owned — 10,039 8 10,047 (1,693 ) Total Assets $ — $ 41,018 $ 12,828 $ 53,846 $ (10,791 ) 2014 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Impaired loans $ — $ 34,864 $ 10,926 $ 45,790 $ (7,017 ) Other real estate owned — 7,828 153 7,981 (1,319 ) Total Assets $ — $ 42,692 $ 11,079 $ 53,771 $ (8,336 ) Impaired loans over $100 thousand are individually reviewed to determine the amount of each loan considered to be at risk of noncollection. The fair value for impaired 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 impaired 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 impaired 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 $9.4 million as of December 31, 2015 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 13 “Goodwill and Other Amortizing Intangible Assets.” There were no material other assets or liabilities measured at fair value on a nonrecurring basis during 2015 . FASB ASC Topic 825-10, “Transition Related to FSP FAS 107-1” and APB 28-1, “Interim Disclosures about Fair Value of Financial Instruments,” require 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 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. Pooled trust preferred collateralized debt obligation values are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and are not based on market exchange, dealer or broker traded transactions. These valuations incorporate certain assumptions and projections in determining the fair value assigned to each instrument. 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, which is not an exit price under FASB ASC Topic 820, “Fair Value Measurements and Disclosures.” 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 $0.2 million at both December 31, 2015 and 2014. See Note 11, “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. Long-term debt and subordinated 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: 2015 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 66,644 $ 66,644 $ 66,644 $ — $ — Interest-bearing deposits 2,808 2,808 2,808 — — Securities available for sale 886,560 886,560 — 848,732 37,828 Other investments 62,952 62,952 — 62,952 — Loans held for sale 5,763 5,763 — 5,763 — Loans 4,683,750 4,690,852 — 30,979 4,659,873 Financial liabilities Deposits 4,195,894 4,198,817 — 4,198,817 — Short-term borrowings 1,510,825 1,510,718 — 1,510,718 — Long-term debt 9,314 9,834 — 9,834 — Subordinated debt 72,167 62,794 — — 62,794 2014 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 72,276 $ 72,276 $ 72,276 $ — $ — Interest-bearing deposits 2,262 2,262 2,262 — — Securities available for sale 1,309,819 1,309,819 — 1,279,400 30,419 Other investments 44,545 44,545 — 44,545 — Loans held for sale 2,502 2,502 — 2,502 — Loans 4,457,308 4,439,766 — 34,864 4,404,902 Financial liabilities Deposits 4,315,511 4,319,997 — 4,319,997 — Short-term borrowings 1,105,876 1,105,867 — 1,105,867 — Long-term debt 89,459 90,319 — 90,319 — Subordinated debt 72,167 62,815 — — 62,815

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The income tax provision for the years ended December 31 is as follows: 2015 2014 2013 (dollars in thousands) Current tax provision for income exclusive of securities transactions: Federal $ 8,610 $ 12,661 $ 2,509 State 68 157 68 Total current tax provision 8,678 12,818 2,577 Deferred tax provision 12,158 4,862 12,704 Total tax provision $ 20,836 $ 17,680 $ 15,281 The statutory to effective tax rate reconciliation for the years ended December 31 is as follows: 2015 2014 2013 Amount % of Amount % of Amount % of (dollars in thousands) Tax at statutory rate $ 24,843 35 % $ 21,747 35 % $ 19,867 35 % Increase (decrease) resulting from: Income from bank owned life insurance (1,894 ) (3 ) (1,926 ) (3 ) (1,939 ) (3 ) Tax-exempt interest income, net (2,232 ) (3 ) (2,133 ) (4 ) (2,600 ) (5 ) Tax credits (61 ) — (134 ) — (144 ) — Other 180 — 126 — 97 — Total tax provision $ 20,836 29 % $ 17,680 28 % $ 15,281 27 % 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 35% 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 35% statutory rate produced an annual effective tax rate of 29% , 28% and 27% for the years ended December 31, 2015 , 2014 and 2013 , respectively. 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: 2015 2014 (dollars in thousands) Deferred tax assets: Allowance for credit losses $ 17,784 $ 18,218 Postretirement benefits other than pensions 641 679 Alternative minimum tax credit carryforward 5,065 8,627 Litigation reserve 0 3,000 Unrealized loss on securities available for sale 1,291 2,463 Writedown of other real estate owned 1,087 603 Deferred compensation 2,113 2,246 Accrued interest on nonaccrual loans 1,452 1,059 Other-than-temporary impairment of securities 89 9,239 Depreciation of assets 879 1,127 Accrued incentives 1,629 1,594 Unfunded loan commitment allowance 1,557 1,078 Accrued severance 808 160 Basis difference in assets acquired 417 — Loan origination fees and costs 141 — Deferred rent 1,258 969 Other 1,105 1,194 Total deferred tax assets 37,316 52,256 Deferred tax liabilities: Basis difference in assets acquired — (344 ) Loan origination fees and costs — (1,337 ) Income from unconsolidated subsidiary (619 ) (603 ) Other (337 ) (318 ) Total deferred tax liabilities (956 ) (2,602 ) Net deferred tax asset $ 36,360 $ 49,654 The net deferred tax asset of $36.4 million as of December 31, 2015 includes a $5.1 million alternative minimum tax credit carryforward with an indefinite life. The significant decrease in the deferred tax asset for other-than-temporary impairment of securities is due to previously recorded impairment charges on trust preferred debt securities being deducted on the 2014 federal tax return based on newly issued IRS guidance. 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. In evaluating deferred tax assets, future taxable income forecasted over the next three years was considered. The amount of future taxable income used in management’s valuation is based upon management approved forecasts, evaluation of historical earnings levels, proven ability to raise capital to support growth or during times of economic stress and consideration of prudent and feasible potential tax strategies. If future events differ from our current forecasts, a valuation allowance may be required, which could have a material impact on our financial condition and results of operations. Based on our evaluation, including the consideration of the weighting of positive and negative evidence, as of December 31, 2015 , 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 through 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, 2015 . 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. During 2015, the IRS completed an examination of our 2013 federal tax return. The examination was closed with no adjustments. Federal and state income tax years 2012 through 2014 are open for examination as of December 31, 2015 .

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [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 $2.7 million in 2015 , $2.6 million in 2014 , and $2.6 million in 2013 . First Commonwealth maintains a Non-Qualified Deferred Compensation Plan ( “ NQDC Plan ” ) to provide deferred compensation for those employees whose total annual or annualized Plan compensation for a calendar year is at least $110,000 . 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. There was no NQDC Plan expense in 2015 , 2014 and 2013 . 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: 2015 2014 2013 (dollars in thousands) Service cost $ — $ — $ — Interest cost on projected benefit obligation 62 62 62 Amortization of transition obligation — — — Gain amortization (4 ) (29 ) (7 ) Net periodic benefit cost $ 58 $ 33 $ 55 The following table sets forth the change in the benefit obligation and plan assets as of December 31: 2015 2014 (dollars in thousands) Change in Benefit Obligation Benefit obligation at beginning of year $ 1,822 $ 1,644 Service cost — — Interest cost 62 62 Amendments — — Actuarial loss (gain) 98 284 Net benefits paid (167 ) (168 ) Benefit obligation at end of year 1,815 1,822 Change in Plan Assets Fair value of plan assets at beginning of year — — Actual return on plan assets — — Employer contributions 167 168 Net benefits paid (167 ) (168 ) Fair value of plan assets at end of year — — Funded Status at End of Year 1,815 1,822 Unrecognized transition obligation — — Unrecognized net gain 15 117 Amounts recognized in retained earnings $ 1,830 $ 1,939 As of December 31, the funded status of the plan is: 2015 2014 (dollars in thousands) Amounts Recognized in the Statement of Financial Condition as Other liabilities $ 1,815 $ 1,822 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: 2015 2014 2013 (dollars in thousands) Amounts recognized in accumulated other comprehensive income, net of tax: Net (gain) loss $ (10 ) $ (76 ) $ (280 ) Transition obligation — — — Total $ (10 ) $ (76 ) $ (280 ) Weighted-average assumptions used to determine the benefit obligation as of December 31 are as follows: 2015 2014 2013 Weighted-average Assumptions Discount rate 3.88 % 3.61 % 4.01 % Health care cost trend: Initial 6.25 % 6.50 % 6.75 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2022 2022 2022 Weighted-average assumptions used to determine the net benefit costs as of December 31 are as follows: 2015 2014 2013 Weighted Average Assumptions for Net Periodic Cost Discount rate 3.61 % 4.01 % 3.31 % Health care cost trend: Initial 6.50 % 6.75 % 7.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2022 2022 2022 Corridor 10.00 % 10.00 % 10.00 % Recognition period for gains and losses 11.0 10.0 11.0 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 $ 73 $ (66 ) Effect on total of service and interest cost components 3 (2 ) As of December 31, 2015 , the projected benefit payments for the next ten years are as follows: Projected Benefit (dollars in thousands) 2016 $ 207 2017 204 2018 190 2019 163 2020 156 2021 - 2025 656 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 2016 are as follows (dollars in thousands): Postretirement (dollars in thousands) Net gain $ (4 ) Transition obligation — Total $ (4 )

Unearned ESOP Shares

Unearned ESOP Shares	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Unearned ESOP Shares	Unearned ESOP Shares During 2012, all employees with at least one year of service were eligible to participate in the ESOP. Contributions to the plan are determined by the Board of Directors and are based upon a prescribed percentage of the annual compensation of all participants. The ESOP acquired shares of First Commonwealth’s common stock in a transaction whereby the ESOP Trust borrowed funds that were guaranteed by First Commonwealth. The borrowed amounts represented leveraged and unallocated shares, and accordingly were recorded as long-term debt with the offset as a reduction of common shareholders’ equity. The borrowing had a balance of $1.6 million at December 31, 2011 and matured in November of 2012. All the remaining shares held as collateral for the loan were released and allocated to participants when the borrowing was repaid. On August 28, 2014, First Commonwealth received a determination letter from the IRS in relation to the termination of the ESOP stating that the termination of the plan does not adversely affect the Plan's federal tax status. All participant funds were distributed as of August 28, 2015.

Incentive Compensation Plan

Incentive Compensation Plan	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Incentive Compensation Plan	Incentive Compensation Plan On 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 3,942,531 shares were still eligible for awards as of December 31, 2015 . Restricted Stock The following provides detail on the restricted stock awards which were issued and outstanding in 2015 , 2014 and 2013 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 June 26, 2015 1,000 $ 9.84 June 26, 2018 1 February 20, 2015 10,000 8.45 February 20, 2018 1 February 20, 2015 34,200 8.45 December 31, 2015 1 February 5, 2015 50,000 8.55 February 5, 2018 1 January 29, 2015 20,170 7.93 December 31, 2015 1 January 15, 2015 20,000 8.38 January 15, 2017 1 November 17, 2014 3,500 9.26 November 17, 2017 1 April 8, 2014 27,500 8.89 April 8, 2017 3 March 24, 2014 46,000 9.18 March 24, 2017 1 March 4, 2014 5,000 8.75 March 4, 2017 1 January 1, 2014 12,626 8.82 December 31, 2014 1 August 16, 2013 3,000 7.57 August 16, 2016 1 May 31, 2013 45,000 7.21 May 31, 2016 3 March 1, 2013 10,000 7.35 March 1, 2016 1 February 24, 2012 34,000 5.96 December 31, 2014 1 February 24, 2012 90,000 5.96 February 24, 2015 1 January 1, 2012 100,000 5.26 January 1, 2016 4 November 21, 2011 10,000 4.41 November 21, 2014 1 April 1, 2011 25,000 6.82 April 1, 2016 1 Compensation expense related to restricted stock was $1.4 million , $1.0 million and $0.5 million in 2015 , 2014 and 2013 , respectively. As of December 31, 2015 , there was $2.5 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: 2015 2014 2013 Shares Weighted Shares Weighted Shares Weighted Outstanding, beginning of the year 265,000 $ 7.08 271,000 $ 6.07 253,000 $ 5.71 Granted 135,370 8.41 94,626 9.03 58,000 7.25 Vested (168,536 ) 6.87 (98,487 ) 6.18 (35,000 ) 5.46 Forfeited — — (2,139 ) 5.96 (5,000 ) 5.96 Outstanding, end of the year 231,834 8.01 265,000 7.08 271,000 6.07 The following provides detail on restricted stock awards estimated to be granted on a performance award basis during 2015 , 2014 and 2013 . 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 January 17, 2011 54,166 3 40 % 100 % 200 % — % 1 January 17, 2014 February 24, 2012 68,000 3 40 % 100 % 200 % — % 1 December 31, 2015 January 28, 2013 128,611 3 40 % 100 % 200 % — % 1 December 31, 2016 January 27, 2014 125,000 3 40 % 100 % 200 % — % 0 December 31, 2016 January 26, 2015 125,000 3 40 % 100 % 200 % — % 0 December 31, 2017 December 30, 2015 60,000 5 0 December 31, 2020 The following table summarizes the estimated unvested target share awards for the Plans as of December 31: 2015 2014 2013 Outstanding, beginning of the year 284,000 250,777 151,333 Granted 185,000 126,389 138,611 Issued (34,200 ) (12,626 ) — Forfeited (114,095 ) (80,540 ) (39,167 ) Outstanding, end of the year 320,705 284,000 250,777 The estimated unvested target awards for the Plans have an estimated fair value of $9.07 per share for each year based on the closing price of Company stock as of December 31, 2015 . Stock Option Plan The First Commonwealth Financial Corporation 1995 Compensatory Stock Option Plan expired on October 15, 2005, and is described below. As of December 31, 2015, there are no outstanding awards under this plan. All of the exercise prices and related number of shares have been adjusted to reflect historical stock splits. The plan permitted the Executive Compensation Committee to grant options for up to 4.5 million shares of First Commonwealth’s common stock through October 15, 2005. The vesting requirements and terms of options granted were at the discretion of the Executive Compensation Committee. Options granted in 2005 vested in the year granted. All options expire ten years from the grant date. All equity compensation plans were approved by security holders. A summary of the status of First Commonwealth’s outstanding stock options as of December 31 and changes for the years ended on those dates is presented below: 12/31/2015 12/31/2014 12/31/2013 Shares Weighted Shares Weighted Shares Weighted Outstanding, beginning of the year 15,000 $ 14.55 27,000 $ 14.49 196,322 $ 11.64 Granted — — — — — — Exercised — — — — — — Forfeited (15,000 ) 14.55 (12,000 ) 14.41 (169,322 ) 11.19 Balance, end of the year — — 15,000 14.55 27,000 14.49 Exercisable at the end of the year — — 15,000 14.55 27,000 14.49 There were no options exercised during the years ended December 31, 2015 , 2014 or 2013 .

Contingent Liabilities

Contingent Liabilities	12 Months Ended
	Dec. 31, 2015
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, 2015, 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 $5 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 Financial Corporation and First Commonwealth Bank were named defendants in an action commenced August 27, 2015 by eight named plaintiffs that is pending in the Court of Common Pleas of Jefferson County, Pennsylvania. The plaintiffs allege that the Bank repossessed motor vehicles, sold the vehicles and sought to collect deficiency balances in a manner that did not comply with the notice requirements of the Pennsylvania Uniform Commercial Code (UCC), charged inappropriate costs and fees, including storage costs for dates that a repossessed vehicle was not in storage, and wrongly filed forms with the Department of Motor Vehicles asserting that the Bank had complied with applicable laws relating to the repossession of the vehicles. The plaintiffs seek to pursue the action as a class action on behalf of the named plaintiffs and other similarly situated plaintiffs who had their automobiles repossessed and seek to recover damages under the UCC and the Pennsylvania Fair Credit Extension Uniformity Act. First Commonwealth and the Bank contest the plaintiffs’ allegations and intend to oppose class certification. The Bank has also asserted counterclaims for breach of contract, set-off and recoupment against the plaintiffs, individually, and as representatives of the putative class. As set forth in the preceding paragraph, all current litigation matters, including this action, are believed to be within the range of reasonably possible losses for such matters in the aggregate set forth above.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2015
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 collectibility 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, 2014 $ 722 Advances 740 Repayments (323 ) December 31, 2015 $ 1,139

Regulatory Restrictions and Cap

Regulatory Restrictions and Capital Adequacy	12 Months Ended
	Dec. 31, 2015
Regulatory Capital Requirements [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. First Commonwealth maintains capital to absorb unexpected losses. In order to provide assurance that our capital levels are adequate for our risk exposure we test our capital position under several stress scenarios on an annual basis. This analysis is subject to Board of Director review and approval. Our most recent capital stress test was completed in December 2015. Effective January 1, 2015, the Company is subject to new regulatory risk-based capital rules adopted by the federal banking agencies implementing Basel III. The most significant changes include higher minimum capital requirements, as the minimum Tier I capital ratio increased from 4.0% to 6.0% , and the establishment of a new common equity Tier I capital ratio with a minimum level of 4.5% . Additionally, the new rules improve the quality of capital by providing stricter eligibility criteria for regulatory capital instruments and provide for a phase-in, beginning January 1, 2016, of a capital conservation buffer of 2.5% of risk-weighted assets. This buffer provides a requirement to hold common equity Tier 1 capital above the minimum risk-based capital requirements, resulting in an effective common equity Tier I risk-weighted asset minimum ratio of 7% on a fully phased-in basis. The Basel III rules also permitted 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. As of December 31, 2015 , First Commonwealth and First Commonwealth Bank met all capital adequacy requirements to which they are subject and was considered well-capitalized under the regulatory rules on a fully phased-in basis. To be considered well-capitalized, the Company must maintain minimum Total risk-based capital, Tier I risk-based capital, Tier I leverage ratio and Common Equity tier I as set forth in the table below: Actual Minimum Capital Required - Basel III Phase-In Schedule Minimum Capital Required - Basel III Fully Phased-In Required to be Considered Well Capital Ratio Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2015 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 682,199 12.25 % $ 445,650 8.00 % $ 584,915 10.50 % $ 557,062 10.00 % First Commonwealth Bank 656,244 11.78 445,642 8.00 584,905 10.50 557,052 10.00 Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 626,939 11.25 % $ 334,237 6.00 % $ 473,503 8.50 % $ 445,650 8.00 % First Commonwealth Bank 600,984 10.79 334,231 6.00 473,494 8.50 445,642 8.00 Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 626,939 9.85 % $ 254,631 4.00 % $ 254,631 4.00 % $ 318,289 5.00 % First Commonwealth Bank 600,984 9.46 254,095 4.00 254,095 4.00 317,618 5.00 Common Equity Tier I to Risk Weighted Assets First Commonwealth Financial Corporation $ 556,939 10.00 % $ 250,678 4.50 % $ 389,944 7.00 % $ 362,091 6.50 % First Commonwealth Bank 535,814 9.62 250,673 4.50 389,937 7.00 362,084 6.50 At December 31, 2014, First Commonwealth and First Commonwealth Bank met all capital adequacy requirements to which they were subject. The following table presents actual and required capital ratios as of December 31, 2014 under the regulatory capital rules then in effect. Actual Regulatory Minimum Well Capitalized Regulatory Guidelines Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2014 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 662,733 12.79 % $ 414,460 8.00 % N/A N/A First Commonwealth Bank 647,500 12.48 415,217 8.00 $ 519,021 10.00 % Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 607,602 11.73 % $ 207,230 4.00 % N/A N/A First Commonwealth Bank 592,369 11.41 207,608 4.00 $ 311,413 6.00 % Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 607,602 9.85 % $ 246,738 4.00 % N/A N/A First Commonwealth Bank 592,369 9.66 245,276 4.00 $ 306,595 5.00 %

Capital

Capital	12 Months Ended
	Dec. 31, 2015
Disclosure Capital Additional Information [Abstract]
Capital	Capital On June 19, 2012 First Commonwealth announced a $50.0 million common stock repurchase program. On January 29, 2013, January 28, 2014 and January 27, 2015, additional share repurchase programs were authorized for up to $25.0 million in shares of the Company’s common stock for each of the three repurchase programs. As of May 31, 2015, all programs were completed resulting in a total of 16,619,205 shares repurchased at an average price of $7.55 per share.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisition	Acquisition On October 1, 2015, the Company completed the acquisition of Columbus, Ohio based First Community Bank for $14.75 million cash. Upon closing of the transaction, First Community Bank merged into First Commonwealth Bank. First Community Bank operated four branch locations which after the merger operate under the First Commonwealth name. The acquisition expanded the Company’s market into the central Ohio area. The table below summarizes the net assets acquired (at fair value) and consideration transferred in connection with the First Community acquisition: Consideration Paid Cash Paid to shareholders $ 14,750 Total consideration paid 14,750 Fair Value of Assets Acquired Cash and cash equivalents 11,217 Investment Securities 25,980 FHLB Stock 832 Loans 61,173 Premises and other equipment 1,801 Core deposit intangible 172 Other real estate 816 Other assets 1,115 Total assets acquired 103,106 Fair Value of Liabilities Assumed Deposits 90,311 Other Liabilities 1,115 Total liabilities assumed 91,426 Total Fair Value of Identifiable Net Assets 11,680 Goodwill $ 3,070 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. Fair value is established by discounting the expected future cash flows with a market discount rate for like maturities and risk instruments. 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.” We acquired $62.5 million in gross loans and recognized a net combined yield and credit market adjustment of $1.3 million . The fair value of the acquired assets and liabilities noted in the table may change during the provisional period, which may last up to twelve months subsequent to the acquisition date. The Company may obtain additional information to refine the valuation of the acquired assets and liabilities and adjust the recorded fair value, although such adjustments are not expected to be significant. Adjustments recorded to the acquired assets and liabilities will be applied prospectively in accordance with ASU No. 2015-16, “Business Combinations.” Costs related to the acquisition totaled $0.9 million . These amounts were expensed as incurred and are recorded as a merger and acquisition related expense in the Consolidated Statements of Income.

Condensed Financial Information

Condensed Financial Information of First Commonwealth Financial Corporation (parent company only)	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only 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, 2015 2014 (dollars in thousands) Assets Cash $ 10,003 $ 10,402 Loans 22 24 Investment in subsidiaries 719,073 712,610 Investment in unconsolidated subsidiary trusts 2,182 2,182 Investment in jointly-owned company 8,978 8,749 Premises and equipment, net 3,780 4,287 Receivable from subsidiaries 441 — Dividends receivable from subsidiaries 714 — Other assets 47,631 50,988 Total assets $ 792,824 $ 789,242 Liabilities and Shareholders’ Equity Accrued expenses and other liabilities $ 1,111 $ 930 Subordinated debentures payable 72,167 72,167 Shareholders’ equity 719,546 716,145 Total liabilities and shareholders’ equity $ 792,824 $ 789,242 Statements of Income For the years ended December 31, 2015 2014 2013 (dollars in thousands) Interest and dividends $ 1 $ 1 $ 1 Dividends from subsidiaries 49,917 49,207 65,140 Interest expense (2,357 ) (2,335 ) (3,128 ) Other income 232 1,251 2,653 Operating expense (4,989 ) (6,766 ) (8,820 ) Income (loss) before taxes and equity in undistributed (loss) earnings of subsidiaries 42,804 41,358 55,846 Applicable income tax benefits 2,528 2,968 3,384 Income before equity in undistributed (loss) earnings of subsidiaries 45,332 44,326 59,230 Equity in undistributed earnings (loss) of subsidiaries 4,811 127 (17,748 ) Net income $ 50,143 $ 44,453 $ 41,482 For the years ended December 31, Statements of Cash Flow 2015 2014 2013 (dollars in thousands) Operating Activities Net income $ 50,143 $ 44,453 $ 41,482 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 493 2,150 3,030 Net gain (loss) on sales of assets 240 — 17 (Increase) decrease in prepaid income taxes (6,993 ) (487 ) 3,044 Undistributed equity in subsidiaries (4,811 ) (127 ) 17,748 Other net 10,753 13,077 12,964 Net cash provided by operating activities 49,825 59,066 78,285 Investing Activities Net change in loans 2 3 4 Purchases of premises and equipment 54 (47 ) (123 ) Proceeds from sale of other assets — 13 1,132 Net cash (used in) provided by investing activities 56 (31 ) 1,013 Financing Activities Repayments of subordinated debenture — — (34,702 ) Discount on dividend reinvestment plan purchases — (65 ) (112 ) Dividends paid (25,089 ) (26,174 ) (22,344 ) Proceeds from reissuance of treasury stock 192 192 176 Purchase of treasury stock (25,383 ) (30,956 ) (33,439 ) Net cash used in financing activities (50,280 ) (57,003 ) (90,421 ) Net increase (decrease) in cash (399 ) 2,032 (11,123 ) Cash at beginning of year 10,402 8,370 19,493 Cash at end of year $ 10,003 $ 10,402 $ 8,370 Cash dividends declared per common share were $0.28 for 2015 , $0.28 for 2014 and $0.23 for 2013 . First Commonwealth Financial Corporation has an unsecured $15.0 million line of credit with another financial institution. As of December 31, 2015 , 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, 2015
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event On February 17, 2016, the Company announced that an additional share repurchase program was authorized by the Board of Directors for up to $25.0 million in shares of the Company’s common stock. Under this program, management is authorized to repurchase shares through Rule 10b5-1 plans, open market purchases, privately negotiated transactions, block purchases or otherwise in accordance with applicable federal securities laws, including Rule 10b-18 of the Securities Exchange Act of 1934. Depending on market conditions and other factors, repurchases may be made at any time or from time to time, without prior notice. First Commonwealth may suspend or discontinue the program at any time.

Statement of Accounting Polic38

Statement of Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
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. 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, an insurance agency and a financial advisor, 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 fifteen counties in central and western Pennsylvania as well as in central 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. 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 and equity 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 determine whether other-than-temporary impairment has occurred. Issuer-specific securities whose market values have fallen below their book values are initially selected for more in-depth analysis based on the percentage decline in value and duration of the decline. 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. Pooled trust preferred collateralized debt obligations are measured by evaluating all relevant credit and structural aspects, determining appropriate performance assumptions and performing a discounted cash flow analysis. This evaluation includes detailed credit, performance and structural evaluations for each piece of collateral. Other factors in the pooled trust preferred collateralized debt obligations valuation include terms of the structure, the cash flow waterfall (for both interest and principal), the over collateralization and interest coverage tests and events of default/liquidation. Based on this review, a determination is made on a case by case basis as to a potential impairment. Declines in the fair value of individual securities below their cost that are not expected to be recovered will result in write-downs of the individual securities to their fair value. The related write-downs are included in earnings as impairment losses.
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 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. A loan is considered to be impaired when, based on current information and events, it is probable that First Commonwealth will be unable to collect principal or interest that is due in accordance with contractual terms of the loan. Impaired 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 impaired 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 collectibility 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.
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 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	Allowance for Credit Losses First Commonwealth maintains an allowance for credit losses at a level deemed sufficient to absorb losses that are inherent in the loan portfolio. First Commonwealth’s management determines and reviews with the Board of Directors the adequacy of the allowance on a quarterly basis to ensure that the provision for credit losses has been charged against earnings in an amount necessary to maintain the allowance at a level that is appropriate based on management’s assessment of probable estimated losses. First Commonwealth’s methodology for assessing the appropriateness of the allowance for credit losses consists of several key elements. These elements include an assessment of individual problem loans, delinquency and loss experience trends and other relevant factors, all of which may be susceptible to significant changes. 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 10, "Loans and Allowance for Credit Losses." First Commonwealth consistently applies the following comprehensive methodology and procedure for determining the allowance for credit losses. All impaired credits in excess of $100 thousand are individually reviewed quarterly. A specific reserve is established for impaired loans that is equal to the total amount of probable unconfirmed losses for the impaired loans that are reviewed. Based on this reserve as a percentage of reviewed loan balances, a reserve is also established for the impaired loan balances that are not individually reviewed. The allowance calculation uses 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. An additional component of the allowance is determined by management based on a qualitative analysis of certain factors related to portfolio risks and economic conditions. Factors considered by management include employment trends, macroeconomic trends, commercial real estate trends and the overall lending environment. 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 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. Management determines the adequacy of the allowance on a quarterly basis, charging the provision against earnings in an amount necessary to maintain the allowance at a level that is appropriate based on management’s assessment of probable estimated losses. The Company’s methodology for assessing the appropriateness of the allowance for off-balance sheet credit exposure consists of analysis of historical usage trends as well as loss history and probability of default rates related to the off-balance sheet category. 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 a determined probability of default as well as a loss given default. This amount is adjusted quarterly and reported as part of other operating expenses on the Consolidated Statements of Income.
Bank Owned Life Insurance	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. Under some of these policies, the beneficiaries receive a portion of the death benefit.
Premises and Equipment	Premises and Equipment 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 seven years
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 by applying a fair value based test. First Commonwealth reviews goodwill annually and again at any quarter-end if a material event occurs during the quarter that may affect goodwill. If goodwill testing is required, an assessment of qualitative factors can be completed before performing the two step goodwill impairment test. If an assessment of qualitative factors determines it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, then the two step goodwill impairment test is not required. 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 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	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 the effective portion 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.
Employee Stock Ownership Plan	Employee Stock Ownership Plan Accounting treatment for First Commonwealth’s Employee Stock Ownership Plan (“ESOP”) described in Note 21 “Unearned ESOP Shares” follows FASB ASC Topic 718, “Compensation—Stock Compensation” for ESOP shares acquired after December 31, 1992 (“new shares”). First Commonwealth’s ESOP borrowed funds were guaranteed by First Commonwealth. The ESOP shares purchased subject to the debt guaranteed by First Commonwealth were recorded as a reduction of common shareholders’ equity by recording unearned ESOP shares. Shares were committed to be released to the ESOP Trust for allocation to plan participants through loan payments. As the shares were committed to be released, the unearned ESOP shares account was credited for the average cost of the shares collateralizing the ESOP borrowed funds. Compensation cost was recognized for these shares in accordance with the provisions of FASB ASC Topic 718 and was based upon the fair market value of the shares that were committed to be released. Additional paid-in capital was charged or credited for the difference between the fair value of the shares committed to be released and the cost of those shares to the ESOP. The borrowed funds related to the unearned ESOP shares were paid off in November 2012. Dividends on unallocated ESOP shares were used for debt service and are reported as a reduction of debt and accrued interest payable. Dividends on allocated ESOP shares were charged to retained earnings and allocated or paid to the plan participants. The average number of common shares outstanding used in calculating earnings per share excludes all unallocated ESOP shares.
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 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, 2015 , First Commonwealth has interest derivative positions 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 less any unallocated ESOP shares. 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 compensatory stock options outstanding and unvested restricted stock grants.
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 1 securities include equity holdings comprised of publicly traded bank stocks which were priced using quoted market prices. • 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, interest rate derivatives that include interest rate swaps, risk participation agreements and foreign currency contracts, certain other real estate owned and certain impaired 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 select Obligations of States and Political Subdivisions, corporate securities, pooled trust preferred collateralized debt obligations, nonmarketable equity investments, certain other real estate owned, certain impaired loans and loans held for sale. 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 18 “Fair Values of Assets and Liabilities” for additional information.
New Accounting Pronouncements, Policy	New Accounting Pronouncements In January 2015, the FASB issued ASU No. 2015-01, “Income Statement - Extraordinary and Unusual Items (Subtopic 225-20), ” which finalizes Proposed ASU No. 2014-220, and eliminates the concept of extraordinary items from U.S. GAAP. Accordingly, this ASU eliminates FASB ASC Subtopic 225-20, "Income Statement - Extraordinary and Unusual Items", which, until now, required that an entity separately classify, present, and disclose extraordinary events and transactions. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In September 2015, the FASB issued ASU No. 2015-16, “Business Combinations (Topic 805), ” which requires that the acquirer recognize adjustments to provisional amounts identified during the measurement period in the reporting period in which the adjustment amounts are determined. The adjustments are required to be presented separately on the face of the income statement or disclosed in the notes to show the portion of current-period earnings by line item that would have been recorded in previous reporting periods if the adjustments to the provisional amounts had been recognized as of the acquisition date. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In August 2015, the FASB issued ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606) ” . In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)", with an original effective date for annual reporting periods beginning after December 15, 2016. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2015-14 deferred the effective date of ASU 2014-09 to annual periods and interim periods within those annual periods beginning after December 15, 2017. We are currently evaluating the potential impact of ASU 2015-14 on our financial statements. In January 2016, the FASB issued ASU 2016-1, “Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. ” ASU 2016-1, among other things, (i) requires equity investments, with certain exceptions, to be measured at fair value with changes in fair value recognized in net income, (ii) simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iii) eliminates the requirement for public business entities to disclose the methods and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet, (iv) requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, (v) requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments, (vi) requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements and (viii) clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities. ASU 2016-1 will be effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is not expected to have a significant impact on our financial statements

Supplemental Comprehensive In39

Supplemental Comprehensive Income Disclosures (Tables)	12 Months Ended
	Dec. 31, 2015
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. 2015 2014 2013 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 (losses) on securities arising during the period $ 2,798 $ (978 ) $ 1,820 $ 25,153 $ (8,803 ) $ 16,350 $ (34,975 ) $ 12,233 $ (22,742 ) Reclassification adjustment for losses (gains) on securities included in net income 153 (54 ) 99 (550 ) 193 (357 ) 1,158 (405 ) 753 Total unrealized gains (losses) on securities 2,951 (1,032 ) 1,919 24,603 (8,610 ) 15,993 (33,817 ) 11,828 (21,989 ) Unrealized gains (losses) on derivatives: Unrealized holding gains on derivatives arising during the period 450 (158 ) 292 472 (165 ) 307 — — — Reclassification adjustment for gains on derivatives included in net income (49 ) 17 (32 ) (10 ) 3 (7 ) — — — Total unrealized gains on derivatives 401 (141 ) 260 462 (162 ) 300 — — — Unrealized (losses) gains for postretirement obligations: Transition obligation — — — — — — — — — Net (loss) gain (102 ) 36 (66 ) (313 ) 109 (204 ) 219 (77 ) 142 Total unrealized (losses) gains for postretirement obligations (102 ) 36 (66 ) (313 ) 109 (204 ) 219 (77 ) 142 Total other comprehensive income (loss) $ 3,250 $ (1,137 ) $ 2,113 $ 24,752 $ (8,663 ) $ 16,089 $ (33,598 ) $ 11,751 $ (21,847 ) 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: 2015 2014 2013 (dollars in thousands) Amounts recognized in accumulated other comprehensive income, net of tax: Net (gain) loss $ (10 ) $ (76 ) $ (280 ) Transition obligation — — — Total $ (10 ) $ (76 ) $ (280 )
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: 2015 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (4,875 ) $ 300 $ 76 $ (4,499 ) Other comprehensive income before reclassification adjustment 1,820 292 2,112 Amounts reclassified from accumulated other comprehensive income (loss) 99 (32 ) 67 Net gain (66 ) (66 ) Net other comprehensive income during the period 1,919 260 (66 ) 2,113 Balance at December 31 $ (2,956 ) $ 560 $ 10 $ (2,386 ) 2014 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ (20,868 ) $ — $ 280 $ (20,588 ) Other comprehensive income before reclassification adjustment 16,350 307 16,657 Amounts reclassified from accumulated other comprehensive income (loss) (357 ) (7 ) (364 ) Net gain (204 ) (204 ) Net other comprehensive income during the period 15,993 300 (204 ) 16,089 Balance at December 31 $ (4,875 ) $ 300 $ 76 $ (4,499 ) 2013 Securities Available for Sale Derivatives Post-Retirement Obligation Accumulated Other Comprehensive Income (dollars in thousands) Balance at January 1 $ 1,121 $ — $ 138 $ 1,259 Other comprehensive income before reclassification adjustment (22,742 ) — (22,742 ) Amounts reclassified from accumulated other comprehensive income (loss) 753 — 753 Net gain 142 142 Net other comprehensive income during the period (21,989 ) — 142 (21,847 ) Balance at December 31 $ (20,868 ) $ — $ 280 $ (20,588 )

Supplemental Cash Flow Disclo40

Supplemental Cash Flow Disclosures (Tables)	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 2013 (dollars in thousands) Cash paid during the period for: Interest $ 15,818 $ 18,943 $ 23,022 Income taxes 8,331 10,700 3,080 Non-cash investing and financing activities: Loans transferred to other real estate owned and repossessed assets 8,257 5,061 12,326 Other real estate owned sold and settled out of period — — 348 Fair value of loans transferred from held to maturity to available for sale 3,196 3,035 20,135 Gross increase (decrease) in market value adjustment to securities available for sale 2,949 24,601 (33,792 ) Gross increase in market value adjustment to derivatives 401 472 — Investments committed to purchase, not settled 694 — — Net assets acquired through acquisition 463 — — Contribution of premises — 682 —

Earnings per Share (Tables)

Earnings per Share (Tables)	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 2013 Weighted average common shares issued 105,563,455 105,563,455 105,563,455 Average treasury shares (16,045,900 ) (12,294,217 ) (8,363,083 ) Average unearned nonvested shares (160,788 ) (154,584 ) (172,215 ) Weighted average common shares and common stock equivalents used to calculate basic earnings per share 89,356,767 93,114,654 97,028,157 Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share — — 1,675 Weighted average common shares and common stock equivalents used to calculate diluted earnings per share 89,356,767 93,114,654 97,029,832
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. 12/31/2015 12/31/2014 12/31/2013 Price Range Price Range Price Range Shares From To Shares From To Shares From To Stock Options — $ — $ — 15,000 $ 14.55 $ 14.55 27,000 $ 14.41 $ 14.55 Restricted Stock 92,002 6.82 9.84 106,977 5.26 9.26 81,770 4.41 7.57

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2015
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 related to the notional amount of derivatives outstanding as well as the notional amount of risk participation agreements participated to other banks at December 31 : 2015 2014 (dollars in thousands) Derivatives not Designated as Hedging Instruments Credit value adjustment $ (542 ) $ (268 ) Notional Amount: Interest rate derivatives 276,860 273,388 Interest rate caps 22,793 6,656 Risk participation agreements 126,612 113,624 Sold credit protection on risk participation agreements (20,383 ) (17,296 ) Derivatives Designated as Hedging Instruments Fair value adjustment 922 472 Notional Amount - Interest rate derivatives 200,000 100,000
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 : 2015 2014 2013 (dollars in thousands) Non-hedging interest rate derivatives: (Decrease) increase in other income $ (274 ) $ (345 ) $ 1,428 Hedging interest rate derivatives: Increase in interest income 2,049 330 — Increase in other income 64 10 —

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Held-to-maturity Securities	Below is an analysis of the amortized cost and fair values of debt securities held to maturity at December 31, 2015 . There were no held to maturity securities at December 31, 2014 . December 31, 2015 Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 4,775 $ — $ (7 ) $ 4,768 Mortgage-Backed Securities – Commercial 16,843 — (247 ) 16,596 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 315,609 30 (1,824 ) 313,815 Mortgage-Backed Securities – Commercial 15,187 — (178 ) 15,009 Obligations of States and Political Subdivisions 31,910 301 (58 ) 32,153 Total Securities Held to Maturity $ 384,324 $ 331 $ (2,314 ) $ 382,341
Analysis of Amortized Cost and Estimated Fair Values of Securities Available for Sale	The amortized cost and estimated fair value of debt securities available for sale at December 31, 2015 , by contractual maturity, are shown below: Amortized Estimated (dollars in thousands) Due within 1 year $ 2,601 $ 2,595 Due after 1 but within 5 years 16,600 16,523 Due after 5 but within 10 years 27,066 27,598 Due after 10 years 44,136 37,977 90,403 84,693 Mortgage-Backed Securities (a) 798,538 799,697 Total Debt Securities $ 888,941 $ 884,390 (a) Mortgage Backed Securities include an amortized cost of $20.0 million and a fair value of $22.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $778.5 million and a fair value of $777.6 million Below is an analysis of the amortized cost and fair values of securities available for sale at December 31 : 2015 2014 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 20,034 $ 2,071 $ (13 ) $ 22,092 $ 23,344 $ 2,595 $ (3 ) $ 25,936 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 778,476 7,983 (8,882 ) 777,577 947,635 13,076 (9,830 ) 950,881 Mortgage-Backed Securities – Commercial 28 — — 28 72 2 — 74 Other Government-Sponsored Enterprises 19,201 2 (85 ) 19,118 269,181 4 (1,308 ) 267,877 Obligations of States and Political Subdivisions 27,066 532 — 27,598 27,058 362 (43 ) 27,377 Corporate Securities 1,897 422 — 2,319 6,682 573 — 7,255 Pooled Trust Preferred Collateralized Debt Obligations 42,239 916 (7,497 ) 35,658 41,926 309 (13,236 ) 28,999 Total Debt Securities 888,941 11,926 (16,477 ) 884,390 1,315,898 16,921 (24,420 ) 1,308,399 Equities 2,170 — — 2,170 1,420 — — 1,420 Total Securities Available for Sale $ 891,111 $ 11,926 $ (16,477 ) $ 886,560 $ 1,317,318 $ 16,921 $ (24,420 ) $ 1,309,819
Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale	(a) Mortgage Backed Securities include an amortized cost of $20.0 million and a fair value of $22.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $778.5 million and a fair value of $777.6 million
Investments Classified by Contractual Maturity Date	The amortized cost and estimated fair value of debt securities held to maturity at December 31, 2015 , 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 $ — $ — Due after 1 but within 5 years 108 108 Due after 5 but within 10 years 27,224 27,487 Due after 10 years 4,578 4,558 31,910 32,153 Mortgage-Backed Securities (a) 352,414 350,188 Total Debt Securities $ 384,324 $ 382,341 (a) Mortgage Backed Securities include an amortized cost of $21.6 million and a fair value of $21.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $330.8 million and a fair value of $328.8 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.

Impairment of Investment Secu44

Impairment of Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2015
Impairment of Investment Securities Disclosure [Abstract]
Schedule of Unrealized Losses and Estimated Fair Values	The following table presents the gross unrealized losses and estimated fair values at December 31, 2015 for both available for sale 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 Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 6,798 $ (20 ) $ — $ — $ 6,798 $ (20 ) Mortgage-Backed Securities – Commercial 16,596 (247 ) — — 16,596 (247 ) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 436,011 (3,293 ) 263,119 (7,413 ) 699,130 (10,706 ) Mortgage-Backed Securities – Commercial 15,009 (178 ) — — 15,009 (178 ) Other Government-Sponsored Enterprises 12,316 (85 ) — — 12,316 (85 ) Obligations of States and Political Subdivisions 7,208 (58 ) — — 7,208 (58 ) Pooled Trust Preferred Collateralized Debt Obligations — — 29,957 (7,497 ) 29,957 (7,497 ) Total Securities $ 493,938 $ (3,881 ) $ 293,076 $ (14,910 ) $ 787,014 $ (18,791 ) At December 31, 2015 , pooled trust preferred collateralized debt obligations accounted for 40% of unrealized losses due to changes in interest rates and the illiquid market for this type of investment. Fixed income securities issued by U.S. Government-sponsored enterprises comprised 59% of total unrealized losses due to changes in market interest rates. Obligations of state and political subdivisions account for the remaining 1% of total unrealized losses as a result of changes in market interest rates. At December 31, 2015 , there were 80 debt securities in an unrealized loss position. There were no equity securities in an unrealized loss position at December 31, 2015 . The following table presents the gross unrealized losses and estimated fair value at December 31, 2014 for available-for-sale and 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 Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 2,318 $ (3 ) $ — $ — $ 2,318 $ (3 ) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 111,646 (419 ) 368,706 (9,411 ) 480,352 (9,830 ) Other Government-Sponsored Enterprises 112,473 (229 ) 130,401 (1,079 ) 242,874 (1,308 ) Obligations of States and Political Subdivisions 3,146 (43 ) — — 3,146 (43 ) Pooled Trust Preferred Collateralized Debt Obligations — — 24,356 (13,236 ) 24,356 (13,236 ) Total Securities $ 229,583 $ (694 ) $ 523,463 $ (23,726 ) $ 753,046 $ (24,420 )
Pooled Trust Preferred Collateralized Debt Obligations	The following table provides additional information related to our pooled trust preferred collateralized debt obligations as of December 31, 2015 : Deal Class Book Estimated Fair Unrealized Moody’s/ Number Deferrals Excess (dollars in thousands) Pre TSL IV Mezzanine $ 1,830 $ 1,336 $ (494 ) B1/BB 6 18.05 % 59.91 % Pre TSL VII Mezzanine 2,963 3,484 521 Ca/- 14 49.68 0.00 Pre TSL VIII Mezzanine 2,000 1,863 (137 ) C/C 29 56.74 0.00 Pre TSL IX Mezzanine 2,376 1,805 (571 ) B1/C 38 29.80 9.90 Pre TSL X Mezzanine 1,613 1,915 302 Caa1/C 43 30.66 0.00 Pre TSL XII Mezzanine 5,688 4,585 (1,103 ) B3/C 66 23.07 0.00 Pre TSL XIII Mezzanine 12,706 10,660 (2,046 ) Ba3/C 56 11.08 37.45 Pre TSL XIV Mezzanine 12,854 9,708 (3,146 ) B1/CC 56 19.72 47.01 MMCap I Mezzanine 209 302 93 Ca/C 8 58.11 83.61 Total $ 42,239 $ 35,658 $ (6,581 )
Cumulative Roll Forward of Credit Losses Recognized in Earnings for Debt Securities Held and Not Intended to be Sold	The table below provides a cumulative roll forward of credit losses recognized in earnings for debt securities held and not intended to be sold for the years ended December 31: 2015 2014 2013 (dollars in thousands) Balance, beginning (a) $ 26,246 $ 27,543 $ 43,274 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 security (b) (1,177 ) (1,297 ) (2,375 ) Reduction for debt securities called during the period (218 ) — (13,356 ) Balance, ending $ 24,851 $ 26,246 $ 27,543 (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 Credi45

Loans and Allowance for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 (dollars in thousands) Commercial, financial, agricultural and other $ 1,150,906 $ 1,052,109 Real estate construction 220,736 120,785 Residential real estate 1,224,465 1,226,344 Commercial real estate 1,479,000 1,405,256 Loans to individuals 608,643 652,814 Total loans and leases net of unearned income $ 4,683,750 $ 4,457,308
Credit Risk Profile by Creditworthiness	The following tables represent our credit risk profile by creditworthiness category for the years ended December 31 : 2015 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 1,074,858 $ 220,267 $ 1,209,606 $ 1,436,714 $ 608,342 $ 4,549,787 Non-Pass OAEM 11,825 442 5,244 30,012 — 47,523 Substandard 64,223 27 9,615 12,274 301 86,440 Doubtful — — — — — — Total Non-Pass 76,048 469 14,859 42,286 301 133,963 Total $ 1,150,906 $ 220,736 $ 1,224,465 $ 1,479,000 $ 608,643 $ 4,683,750 2014 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 983,357 $ 112,536 $ 1,214,920 $ 1,353,773 $ 652,596 $ 4,317,182 Non-Pass OAEM 32,563 8,013 2,315 29,479 — 72,370 Substandard 32,028 236 9,109 22,004 218 63,595 Doubtful 4,161 — — — — 4,161 Total Non-Pass 68,752 8,249 11,424 51,483 218 140,126 Total $ 1,052,109 $ 120,785 $ 1,226,344 $ 1,405,256 $ 652,814 $ 4,457,308
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. 2015 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 364 $ 49 $ 129 $ 23,653 $ 24,195 $ 1,126,711 $ 1,150,906 Real estate construction 280 — — 28 308 220,428 220,736 Residential real estate 4,175 1,055 1,315 6,500 13,045 1,211,420 1,224,465 Commercial real estate 781 — 65 6,223 7,069 1,471,931 1,479,000 Loans to individuals 2,998 774 946 301 5,019 603,624 608,643 Total $ 8,598 $ 1,878 $ 2,455 $ 36,705 $ 49,636 $ 4,634,114 $ 4,683,750 2014 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 2,816 $ 213 $ 264 $ 27,007 $ 30,300 $ 1,021,809 $ 1,052,109 Real estate construction — 1 — 236 237 120,548 120,785 Residential real estate 5,162 1,295 1,077 7,900 15,434 1,210,910 1,226,344 Commercial real estate 1,797 122 — 7,306 9,225 1,396,031 1,405,256 Loans to individuals 3,698 1,059 1,278 218 6,253 646,561 652,814 Total $ 13,473 $ 2,690 $ 2,619 $ 42,667 $ 61,449 $ 4,395,859 $ 4,457,308
Recorded Investment and Unpaid Principal Balance for Impaired Loans with Associated Allowance	The following tables include the recorded investment and unpaid principal balance for impaired loans with the associated allowance amount, if applicable, as of December 31, 2015 and 2014 . Also presented are the average recorded investment in impaired loans and the related amount of interest recognized while the loan was considered impaired for the years ended December 31, 2015 , 2014 and 2013 . 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. 2015 Recorded Unpaid Related Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 11,344 $ 15,673 $ 17,692 $ 216 Real estate construction 28 117 95 — Residential real estate 9,952 11,819 10,635 172 Commercial real estate 7,562 9,449 7,890 90 Loans to individuals 421 507 338 4 Subtotal 29,307 37,565 36,650 482 With an allowance recorded: Commercial, financial, agricultural and other 20,132 22,590 $ 6,952 7,731 129 Real estate construction — — — — — Residential real estate 461 672 51 403 — Commercial real estate 944 1,008 42 674 4 Loans to individuals — — — — — Subtotal 21,537 24,270 7,045 8,808 133 Total $ 50,844 $ 61,835 $ 7,045 $ 45,458 $ 615 2014 Recorded Unpaid Related Average Interest With no related allowance recorded: Commercial, financial, agricultural and other $ 9,439 $ 10,937 $ 11,536 $ 133 Real estate construction 236 476 1,190 19 Residential real estate 10,773 12,470 11,592 210 Commercial real estate 8,768 10,178 8,830 98 Loans to individuals 288 337 308 4 Subtotal 29,504 34,398 33,456 464 With an allowance recorded: Commercial, financial, agricultural and other 24,826 25,583 $ 9,304 15,797 143 Real estate construction — — — — — Residential real estate 367 380 56 357 14 Commercial real estate 554 554 101 184 4 Loans to individuals — — — — — Subtotal 25,747 26,517 9,461 16,338 161 Total $ 55,251 $ 60,915 $ 9,461 $ 49,794 $ 625 2013 Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 14,454 $ 73 Real estate construction 5,923 47 Residential real estate 9,280 211 Commercial real estate 27,881 250 Loans to individuals 255 3 Subtotal 57,793 584 With an allowance recorded: Commercial, financial, agricultural and other 16,479 64 Real estate construction 515 — Residential real estate 3,200 31 Commercial real estate 188 — Loans to individuals — — Subtotal 20,382 95 Total $ 78,175 $ 679
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 : 2015 2014 2013 (dollars in thousands) Troubled debt restructured loans Accrual status $ 14,139 $ 12,584 $ 13,495 Nonaccrual status 12,360 16,952 16,980 Total $ 26,499 $ 29,536 $ 30,475 Commitments Unused lines of credit 3,252 4,120 452 The following table provides information related to restructured loans that were considered to be in default during the as of December 31 : 2015 2014 2013 Number of Recorded Number of Recorded Number of Recorded (dollars in thousands) Residential real estate 3 $ 97 2 $ 7 1 $ 19 Commercial real estate — — 1 6 — — Total 3 $ 97 3 $ 13 1 $ 19
Troubled Debt Restructurings is 90 Days or More Past Due	he 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 : 2015 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 12 $ 1,751 $ 3,195 $ 4,527 $ 9,473 $ 8,823 $ 1,330 Residential real estate 32 — 296 1,414 1,710 1,575 2 Commercial real estate 1 — — 464 464 389 — Loans to individuals 16 3 167 35 205 169 — Total 61 $ 1,754 $ 3,658 $ 6,440 $ 11,852 $ 10,956 $ 1,332 2014 Type of Modification Number Extend Modify Modify Other Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 9 $ 5,487 $ — $ 14,529 $ — $ 20,016 $ 13,785 $ 4,665 Residential real estate 52 — 629 1,797 — 2,426 2,062 — Commercial real estate 1 — — 8 — 8 6 — Loans to individuals 15 — 103 47 — 150 114 — Total 77 $ 5,487 $ 732 $ 16,381 $ — $ 22,600 $ 15,967 $ 4,665 2013 Type of Modification Number Extend Modify Modify Other Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 14 $ 3,462 $ — $ 1,677 $ — $ 5,139 $ 3,104 $ 906 Residential real estate 46 347 418 2,116 — 2,881 2,316 161 Commercial real estate 5 571 1,499 145 — 2,215 2,184 34 Loans to individuals 17 10 101 33 — 144 109 — Total 82 $ 4,390 $ 2,018 $ 3,971 $ — $ 10,379 $ 7,713 $ 1,101
Allowance for Credit Losses	The following tables provide detail related to the allowance for credit losses for the years ended December 31 . During 2013, the negative $5.9 million provision for credit losses related to the unallocated portion of the allowance is a result of it no longer being treated as a separate component of the allowance but instead is now incorporated into the reserve provided for each loan category. This portion of the allowance for credit losses reflects the qualitative or environmental factors that are likely to cause estimated credit losses to differ from historical loss experience. 2015 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 29,627 $ 2,063 $ 3,664 $ 11,881 $ 4,816 $ 52,051 Charge-offs (11,429 ) (8 ) (1,539 ) (1,538 ) (4,354 ) (18,868 ) Recoveries 1,097 84 587 229 684 2,681 Provision (credit) 11,740 (1,252 ) (106 ) 1,352 3,214 14,948 Ending Balance $ 31,035 $ 887 $ 2,606 $ 11,924 $ 4,360 $ 50,812 Ending balance: individually evaluated for impairment $ 6,952 $ — $ 51 $ 42 $ — $ 7,045 Ending balance: collectively evaluated for impairment 24,083 887 2,555 11,882 4,360 43,767 Loans: Ending balance 1,150,906 220,736 1,224,465 1,479,000 608,643 4,683,750 Ending balance: individually evaluated for impairment 30,767 — 6,099 7,143 — 44,009 Ending balance: collectively evaluated for impairment 1,120,139 220,736 1,218,366 1,471,857 608,643 4,639,741 2014 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 22,663 $ 6,600 $ 7,727 $ 11,778 $ 5,457 $ 54,225 Charge-offs (8,911 ) (296 ) (3,153 ) (1,148 ) (3,964 ) (17,472 ) Recoveries 734 1,340 650 612 766 4,102 Provision (credit) 15,141 (5,581 ) (1,560 ) 639 2,557 11,196 Ending Balance $ 29,627 $ 2,063 $ 3,664 $ 11,881 $ 4,816 $ 52,051 Ending balance: individually evaluated for impairment $ 9,304 $ — $ 56 $ 101 $ — $ 9,461 Ending balance: collectively evaluated for impairment 20,323 2,063 3,608 11,780 4,816 42,590 Loans: Ending balance 1,052,109 120,785 1,226,344 1,405,256 652,814 4,457,308 Ending balance: individually evaluated for impairment 33,332 193 7,127 7,790 — 48,442 Ending balance: collectively evaluated for impairment 1,018,777 120,592 1,219,217 1,397,466 652,814 4,408,866 2013 Commercial, Real estate Residential Commercial Loans to Unallocated Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 19,852 $ 8,928 $ 5,908 $ 22,441 $ 4,132 $ 5,926 $ 67,187 Charge-offs (18,399 ) (773 ) (1,814 ) (10,513 ) (3,679 ) — (35,178 ) Recoveries 455 501 1,264 136 633 — 2,989 Provision (credit) 20,755 (2,056 ) 2,369 (286 ) 4,371 (5,926 ) 19,227 Ending Balance $ 22,663 $ 6,600 $ 7,727 $ 11,778 $ 5,457 $ — $ 54,225 Ending balance: individually evaluated for impairment $ 7,364 $ 94 $ 1,282 $ 84 $ — $ — $ 8,824 Ending balance: collectively evaluated for impairment 15,299 6,506 6,445 11,694 5,457 — 45,401 Loans: Ending balance 1,021,056 93,289 1,262,718 1,296,472 610,298 4,283,833 Ending balance: individually evaluated for impairment 27,251 3,844 9,349 12,151 — 52,595 Ending balance: collectively evaluated for impairment 993,805 89,445 1,253,369 1,284,321 610,298 4,231,238

Commitments and Letters of Cr46

Commitments and Letters of Credit (Tables)	12 Months Ended
	Dec. 31, 2015
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 : 2015 2014 (dollars in thousands) Financial instruments whose contract amounts represent credit risk: Commitments to extend credit $ 1,643,187 $ 1,635,948 Financial standby letters of credit 17,843 36,075 Performance standby letters of credit 26,497 25,915 Commercial letters of credit 1,672 2,611

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Schedule of Premises and Equipment	Premises and equipment are described as follows: Estimated Useful Life 2015 2014 (dollars in thousands) Land Indefinite $ 12,185 $ 12,098 Buildings and improvements 10-50 years 77,086 75,873 Leasehold improvements 5-40 years 14,518 14,229 Furniture and equipment 3-10 years 59,463 59,034 Software 3-7 years 34,472 37,007 Subtotal 197,724 198,241 Less accumulated depreciation and amortization 134,270 133,252 Total premises and equipment $ 63,454 $ 64,989
Schedule of Future Minimum Rentals	First Commonwealth leases various premises and assorted equipment under non-cancellable agreements. Total future minimal rental commitments at December 31, 2015 , were as follows: Premises Equipment (dollars in thousands) 2016 $ 3,339 $ 66 2017 3,004 53 2018 2,809 9 2019 2,531 — 2020 1,981 — Thereafter 10,360 — Total $ 24,024 $ 128

Goodwill and Other Amortizing48

Goodwill and Other Amortizing Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill Disclosure [Abstract]
Summarized Other Intangible Assets	The following table summarizes other intangible assets, which for each year includes only core deposit intangibles: Gross Intangible Assets Accumulated Amortization Net Intangible Assets (dollars in thousands) December 31, 2015 Customer deposit intangibles $ 19,142 $ (18,619 ) $ 523 Customer list intangible $ 984 $ (276 ) $ 708 Total other intangible assets $ 20,126 $ (18,895 ) $ 1,231 December 31, 2014 Customer deposit intangibles $ 22,470 $ (21,773 ) $ 697 Customer list intangible $ 984 $ (16 ) $ 968 Total other intangible assets $ 23,454 $ (21,789 ) $ 1,665
Estimated Amortization Expense of Core Deposit Intangibles	The following presents the estimated amortization expense of core deposit intangibles and the customer intangible list: Core Deposit Intangibles Customer Intangible List Total (dollars in thousands) 2016 $ 207 $ 168 $ 375 2017 90 130 220 2018 87 99 186 2019 78 77 155 2020 18 59 77 Thereafter 43 175 218 Total $ 523 $ 708 $ 1,231

Interest-Bearing Deposits (Tabl

Interest-Bearing Deposits (Tables)	12 Months Ended
	Dec. 31, 2015
Deposits [Abstract]
Components of Interest-Bearing Deposits	Components of interest-bearing deposits at December 31 were as follows: 2015 2014 (dollars in thousands) Interest-bearing demand deposits $ 86,365 $ 81,851 Savings deposits 2,390,607 2,402,288 Time deposits 602,233 842,345 Total interest-bearing deposits $ 3,079,205 $ 3,326,484
Scheduled Maturities of Time Deposits	Included in time deposits at December 31, 2015 , were certificates of deposit with the following scheduled maturities (dollars in thousands): 2016 $ 354,324 2017 113,391 2018 45,744 2019 54,276 2020 and thereafter 34,498 Total $ 602,233

Short-term Borrowings (Tables)

Short-term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
Summary of Short-Term Borrowings	Short-term borrowings at December 31 were as follows: 2015 2014 2013 Ending Average Average Ending Average Average Ending Average Average (dollars in thousands) Federal funds purchased $ 4,000 $ 14,832 0.36 % $ 9,000 $ 11,691 0.36 % $ 16,000 $ 11,982 0.36 % Borrowings from FHLB 1,400,000 1,117,522 0.42 945,000 644,651 0.31 478,100 335,449 0.27 Securities sold under agreements to repurchase 106,825 120,177 0.23 151,876 159,051 0.24 132,515 130,957 0.25 Total $ 1,510,825 $ 1,252,531 0.40 $ 1,105,876 $ 815,393 0.30 $ 626,615 $ 478,388 0.26 Maximum total at any month-end $ 1,510,825 $ 1,105,876 $ 626,615 Weighted average rate at year-end 0.53 % 0.30 % 0.27 %
Interest Expense on Short-Term Borrowings	Interest expense on short-term borrowings for the years ended December 31 is detailed below: 2015 2014 2013 (dollars in thousands) Federal funds purchased $ 54 $ 42 $ 43 Borrowings from FHLB 4,684 2,019 893 Securities sold under agreements to repurchase 280 388 326 Total interest on short-term borrowings $ 5,018 $ 2,449 $ 1,262

Subordinated Debentures (Tables

Subordinated Debentures (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure Subordinated Debentures [Abstract]
Subordinated Debentures Outstanding	Subordinated Debentures outstanding at December 31 are as follows: 2015 2014 Due Amount Rate Amount Rate (dollars in thousands) Owed to: First Commonwealth Capital Trust II 2034 $ 30,929 LIBOR + 2.85 $ 30,929 LIBOR + 2.85 First Commonwealth Capital Trust III 2034 41,238 LIBOR + 2.85 41,238 LIBOR + 2.85 Total $ 72,167 $ 72,167

Other Long-term Debt (Tables)

Other Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Summary of Other Long-Term Debt	Other long-term debt at December 31 follows: 2015 2014 Amount Weighted Weighted Amount Weighted Weighted (dollars in thousands) Borrowings from FHLB due: 2015 $ 80,142 0.82 % 0.82 % 2016 $ 563 3.82 % 3.82 % 563 3.82 3.82 2017 585 3.83 3.83 585 3.83 3.83 2018 607 3.83 3.83 607 3.83 3.83 2019 631 3.83 3.83 631 3.84 3.84 2020 659 3.84 3.84 Thereafter 6,269 3.81 3.81 6,931 3.81 3.81 Total $ 9,314 $ 89,459

Fair Values of Assets and Lia53

Fair Values of Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
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 Pooled Trust Preferred Securities $ 35,658 Discounted Cash Flow Probability of default 0% - 100% (13.38%) Prepayment rates 0% - 73.28% (5.07%) Discount rates 5.25% - 12.00% (a) Equities 2,170 Par Value N/A N/A Impaired Loans 2,859 (b) Gas Reserve study Discount rate 10.00% Gas per MCF $2.34 - $3.71 (c) Oil per BBL/d $42.56 - $65.13 (c) 2,963 (b) Discounted Cash Flow Discount Rate 1.90% - 4.81% Other Real Estate Owned 8 Internal Valuation N/A N/A (a) incorporates spread over the risk free rate related primarily to credit quality and illiquidity of securities. (b) the remainder of impaired loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation. (c) unobservable inputs are defined as follows: MCF—million cubic feet; BBL/d—barrels per day
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: 2015 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 22,092 $ — $ 22,092 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 777,577 — 777,577 Mortgage-Backed Securities—Commercial — 28 — 28 Other Government-Sponsored Enterprises — 19,118 — 19,118 Obligations of States and Political Subdivisions — 27,598 — 27,598 Corporate Securities — 2,319 — 2,319 Pooled Trust Preferred Collateralized Debt Obligations — — 35,658 35,658 Total Debt Securities — 848,732 35,658 884,390 Equities — — 2,170 2,170 Total Securities Available for Sale — 848,732 37,828 886,560 Other Investments — 62,952 — 62,952 Loans Held for Sale — 5,763 — 5,763 Other Assets (a) — 11,273 — 11,273 Total Assets $ — $ 928,720 $ 37,828 $ 966,548 Other Liabilities (a) $ — $ 10,829 $ — $ 10,829 Total Liabilities $ — $ 10,829 $ — $ 10,829 (a) Hedging and non-hedging interest rate derivatives 2014 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities—Residential $ — $ 25,936 $ — $ 25,936 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities—Residential — 950,881 — 950,881 Mortgage-Backed Securities—Commercial — 74 — 74 Other Government-Sponsored Enterprises — 267,877 — 267,877 Obligations of States and Political Subdivisions — 27,377 — 27,377 Corporate Securities — 7,255 — 7,255 Pooled Trust Preferred Collateralized Debt Obligations — — 28,999 28,999 Total Debt Securities — 1,279,400 28,999 1,308,399 Equities — — 1,420 1,420 Total Securities Available for Sale — 1,279,400 30,419 1,309,819 Other Investments — 44,545 — 44,545 Loans Held for Sale — 2,502 — 2,502 Other Assets (a) — 11,186 — 11,186 Total Assets $ — $ 1,337,633 $ 30,419 $ 1,368,052 Other Liabilities (a) $ — $ 10,671 $ — $ 10,671 Total Liabilities $ — $ 10,671 $ — $ 10,671 (a) Non-hedging interest rate derivatives
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, 2015 : Pooled Trust Equities Loans Total (dollars in thousands) Balance, beginning of year $ 28,999 $ 1,420 $ — $ 30,419 Total gains or losses Included in earnings 111 — — 111 Included in other comprehensive income 7,608 — — 7,608 Purchases, issuances, sales, and settlements Purchases — 750 — 750 Issuances — — — — Sales — — — — Settlements (1,060 ) — — (1,060 ) Transfers from Level 3 — — — — Transfers into Level 3 — — — — Balance, end of year $ 35,658 $ 2,170 $ — $ 37,828 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, 2015 . During the year ended December 31, 2015 , there were no transfers between fair value Levels 1 2, and 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, 2014 : Pooled Trust Equities Loans Other Total (dollars in thousands) Balance, beginning of year $ 23,523 $ 1,420 $ — $ — $ 24,943 Total gains or losses Included in earnings — — 77 — 77 Included in other comprehensive income 7,162 — — — 7,162 Purchases, issuances, sales, and settlements Purchases — — — — — Issuances — — — — — Sales — — (3,112 ) — (3,112 ) Settlements (1,686 ) — — — (1,686 ) Transfers from Level 3 — — — — — Transfers into Level 3 — — 3,035 — 3,035 Balance, end of year $ 28,999 $ 1,420 $ — $ — $ 30,419
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: 2015 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Impaired loans $ — $ 30,979 $ 12,820 $ 43,799 $ (9,098 ) Other real estate owned — 10,039 8 10,047 (1,693 ) Total Assets $ — $ 41,018 $ 12,828 $ 53,846 $ (10,791 ) 2014 Level 1 Level 2 Level 3 Total Total (dollars in thousands) Impaired loans $ — $ 34,864 $ 10,926 $ 45,790 $ (7,017 ) Other real estate owned — 7,828 153 7,981 (1,319 ) Total Assets $ — $ 42,692 $ 11,079 $ 53,771 $ (8,336 )
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: 2015 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 66,644 $ 66,644 $ 66,644 $ — $ — Interest-bearing deposits 2,808 2,808 2,808 — — Securities available for sale 886,560 886,560 — 848,732 37,828 Other investments 62,952 62,952 — 62,952 — Loans held for sale 5,763 5,763 — 5,763 — Loans 4,683,750 4,690,852 — 30,979 4,659,873 Financial liabilities Deposits 4,195,894 4,198,817 — 4,198,817 — Short-term borrowings 1,510,825 1,510,718 — 1,510,718 — Long-term debt 9,314 9,834 — 9,834 — Subordinated debt 72,167 62,794 — — 62,794 2014 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 72,276 $ 72,276 $ 72,276 $ — $ — Interest-bearing deposits 2,262 2,262 2,262 — — Securities available for sale 1,309,819 1,309,819 — 1,279,400 30,419 Other investments 44,545 44,545 — 44,545 — Loans held for sale 2,502 2,502 — 2,502 — Loans 4,457,308 4,439,766 — 34,864 4,404,902 Financial liabilities Deposits 4,315,511 4,319,997 — 4,319,997 — Short-term borrowings 1,105,876 1,105,867 — 1,105,867 — Long-term debt 89,459 90,319 — 90,319 — Subordinated debt 72,167 62,815 — — 62,815

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
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: 2015 2014 2013 (dollars in thousands) Current tax provision for income exclusive of securities transactions: Federal $ 8,610 $ 12,661 $ 2,509 State 68 157 68 Total current tax provision 8,678 12,818 2,577 Deferred tax provision 12,158 4,862 12,704 Total tax provision $ 20,836 $ 17,680 $ 15,281
Schedule of Effective Income Tax Rate Reconciliation	The statutory to effective tax rate reconciliation for the years ended December 31 is as follows: 2015 2014 2013 Amount % of Amount % of Amount % of (dollars in thousands) Tax at statutory rate $ 24,843 35 % $ 21,747 35 % $ 19,867 35 % Increase (decrease) resulting from: Income from bank owned life insurance (1,894 ) (3 ) (1,926 ) (3 ) (1,939 ) (3 ) Tax-exempt interest income, net (2,232 ) (3 ) (2,133 ) (4 ) (2,600 ) (5 ) Tax credits (61 ) — (134 ) — (144 ) — Other 180 — 126 — 97 — Total tax provision $ 20,836 29 % $ 17,680 28 % $ 15,281 27 %
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: 2015 2014 (dollars in thousands) Deferred tax assets: Allowance for credit losses $ 17,784 $ 18,218 Postretirement benefits other than pensions 641 679 Alternative minimum tax credit carryforward 5,065 8,627 Litigation reserve 0 3,000 Unrealized loss on securities available for sale 1,291 2,463 Writedown of other real estate owned 1,087 603 Deferred compensation 2,113 2,246 Accrued interest on nonaccrual loans 1,452 1,059 Other-than-temporary impairment of securities 89 9,239 Depreciation of assets 879 1,127 Accrued incentives 1,629 1,594 Unfunded loan commitment allowance 1,557 1,078 Accrued severance 808 160 Basis difference in assets acquired 417 — Loan origination fees and costs 141 — Deferred rent 1,258 969 Other 1,105 1,194 Total deferred tax assets 37,316 52,256 Deferred tax liabilities: Basis difference in assets acquired — (344 ) Loan origination fees and costs — (1,337 ) Income from unconsolidated subsidiary (619 ) (603 ) Other (337 ) (318 ) Total deferred tax liabilities (956 ) (2,602 ) Net deferred tax asset $ 36,360 $ 49,654

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [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: 2015 2014 2013 (dollars in thousands) Service cost $ — $ — $ — Interest cost on projected benefit obligation 62 62 62 Amortization of transition obligation — — — Gain amortization (4 ) (29 ) (7 ) Net periodic benefit cost $ 58 $ 33 $ 55
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: 2015 2014 (dollars in thousands) Change in Benefit Obligation Benefit obligation at beginning of year $ 1,822 $ 1,644 Service cost — — Interest cost 62 62 Amendments — — Actuarial loss (gain) 98 284 Net benefits paid (167 ) (168 ) Benefit obligation at end of year 1,815 1,822 Change in Plan Assets Fair value of plan assets at beginning of year — — Actual return on plan assets — — Employer contributions 167 168 Net benefits paid (167 ) (168 ) Fair value of plan assets at end of year — — Funded Status at End of Year 1,815 1,822 Unrecognized transition obligation — — Unrecognized net gain 15 117 Amounts recognized in retained earnings $ 1,830 $ 1,939
Schedule of Amounts Recognized as Other Liabilities	As of December 31, the funded status of the plan is: 2015 2014 (dollars in thousands) Amounts Recognized in the Statement of Financial Condition as Other liabilities $ 1,815 $ 1,822
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. 2015 2014 2013 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 (losses) on securities arising during the period $ 2,798 $ (978 ) $ 1,820 $ 25,153 $ (8,803 ) $ 16,350 $ (34,975 ) $ 12,233 $ (22,742 ) Reclassification adjustment for losses (gains) on securities included in net income 153 (54 ) 99 (550 ) 193 (357 ) 1,158 (405 ) 753 Total unrealized gains (losses) on securities 2,951 (1,032 ) 1,919 24,603 (8,610 ) 15,993 (33,817 ) 11,828 (21,989 ) Unrealized gains (losses) on derivatives: Unrealized holding gains on derivatives arising during the period 450 (158 ) 292 472 (165 ) 307 — — — Reclassification adjustment for gains on derivatives included in net income (49 ) 17 (32 ) (10 ) 3 (7 ) — — — Total unrealized gains on derivatives 401 (141 ) 260 462 (162 ) 300 — — — Unrealized (losses) gains for postretirement obligations: Transition obligation — — — — — — — — — Net (loss) gain (102 ) 36 (66 ) (313 ) 109 (204 ) 219 (77 ) 142 Total unrealized (losses) gains for postretirement obligations (102 ) 36 (66 ) (313 ) 109 (204 ) 219 (77 ) 142 Total other comprehensive income (loss) $ 3,250 $ (1,137 ) $ 2,113 $ 24,752 $ (8,663 ) $ 16,089 $ (33,598 ) $ 11,751 $ (21,847 ) 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: 2015 2014 2013 (dollars in thousands) Amounts recognized in accumulated other comprehensive income, net of tax: Net (gain) loss $ (10 ) $ (76 ) $ (280 ) Transition obligation — — — Total $ (10 ) $ (76 ) $ (280 )
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: 2015 2014 2013 Weighted-average Assumptions Discount rate 3.88 % 3.61 % 4.01 % Health care cost trend: Initial 6.25 % 6.50 % 6.75 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2022 2022 2022
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: 2015 2014 2013 Weighted-average Assumptions Discount rate 3.88 % 3.61 % 4.01 % Health care cost trend: Initial 6.25 % 6.50 % 6.75 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2022 2022 2022 Weighted-average assumptions used to determine the net benefit costs as of December 31 are as follows: 2015 2014 2013 Weighted Average Assumptions for Net Periodic Cost Discount rate 3.61 % 4.01 % 3.31 % Health care cost trend: Initial 6.50 % 6.75 % 7.00 % Health care cost trend: Ultimate 4.75 % 4.75 % 4.75 % Year ultimate reached 2022 2022 2022 Corridor 10.00 % 10.00 % 10.00 % Recognition period for gains and losses 11.0 10.0 11.0
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 $ 73 $ (66 ) Effect on total of service and interest cost components 3 (2 )
Schedule of Projected Benefit Payments	As of December 31, 2015 , the projected benefit payments for the next ten years are as follows: Projected Benefit (dollars in thousands) 2016 $ 207 2017 204 2018 190 2019 163 2020 156 2021 - 2025 656
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 2016 are as follows (dollars in thousands): Postretirement (dollars in thousands) Net gain $ (4 ) Transition obligation — Total $ (4 )

Incentive Compensation Plan (Ta

Incentive Compensation Plan (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [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 2015 , 2014 and 2013 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 June 26, 2015 1,000 $ 9.84 June 26, 2018 1 February 20, 2015 10,000 8.45 February 20, 2018 1 February 20, 2015 34,200 8.45 December 31, 2015 1 February 5, 2015 50,000 8.55 February 5, 2018 1 January 29, 2015 20,170 7.93 December 31, 2015 1 January 15, 2015 20,000 8.38 January 15, 2017 1 November 17, 2014 3,500 9.26 November 17, 2017 1 April 8, 2014 27,500 8.89 April 8, 2017 3 March 24, 2014 46,000 9.18 March 24, 2017 1 March 4, 2014 5,000 8.75 March 4, 2017 1 January 1, 2014 12,626 8.82 December 31, 2014 1 August 16, 2013 3,000 7.57 August 16, 2016 1 May 31, 2013 45,000 7.21 May 31, 2016 3 March 1, 2013 10,000 7.35 March 1, 2016 1 February 24, 2012 34,000 5.96 December 31, 2014 1 February 24, 2012 90,000 5.96 February 24, 2015 1 January 1, 2012 100,000 5.26 January 1, 2016 4 November 21, 2011 10,000 4.41 November 21, 2014 1 April 1, 2011 25,000 6.82 April 1, 2016 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: 2015 2014 2013 Shares Weighted Shares Weighted Shares Weighted Outstanding, beginning of the year 265,000 $ 7.08 271,000 $ 6.07 253,000 $ 5.71 Granted 135,370 8.41 94,626 9.03 58,000 7.25 Vested (168,536 ) 6.87 (98,487 ) 6.18 (35,000 ) 5.46 Forfeited — — (2,139 ) 5.96 (5,000 ) 5.96 Outstanding, end of the year 231,834 8.01 265,000 7.08 271,000 6.07
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 2015 , 2014 and 2013 . 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 January 17, 2011 54,166 3 40 % 100 % 200 % — % 1 January 17, 2014 February 24, 2012 68,000 3 40 % 100 % 200 % — % 1 December 31, 2015 January 28, 2013 128,611 3 40 % 100 % 200 % — % 1 December 31, 2016 January 27, 2014 125,000 3 40 % 100 % 200 % — % 0 December 31, 2016 January 26, 2015 125,000 3 40 % 100 % 200 % — % 0 December 31, 2017 December 30, 2015 60,000 5 0 December 31, 2020
Unvested Target Award	The following table summarizes the estimated unvested target share awards for the Plans as of December 31: 2015 2014 2013 Outstanding, beginning of the year 284,000 250,777 151,333 Granted 185,000 126,389 138,611 Issued (34,200 ) (12,626 ) — Forfeited (114,095 ) (80,540 ) (39,167 ) Outstanding, end of the year 320,705 284,000 250,777
Outstanding Stock Options	A summary of the status of First Commonwealth’s outstanding stock options as of December 31 and changes for the years ended on those dates is presented below: 12/31/2015 12/31/2014 12/31/2013 Shares Weighted Shares Weighted Shares Weighted Outstanding, beginning of the year 15,000 $ 14.55 27,000 $ 14.49 196,322 $ 11.64 Granted — — — — — — Exercised — — — — — — Forfeited (15,000 ) 14.55 (12,000 ) 14.41 (169,322 ) 11.19 Balance, end of the year — — 15,000 14.55 27,000 14.49 Exercisable at the end of the year — — 15,000 14.55 27,000 14.49

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Loans to Related Parties	The following is an analysis of loans to related parties (dollars in thousands): December 31, 2014 $ 722 Advances 740 Repayments (323 ) December 31, 2015 $ 1,139

Regulatory Restrictions and C58

Regulatory Restrictions and Capital Adequacy (Tables)	12 Months Ended
	Dec. 31, 2015
Regulatory Capital Requirements [Abstract]
Schedule of Capital Amount and Ratio Considered to be Capitalized	To be considered well-capitalized, the Company must maintain minimum Total risk-based capital, Tier I risk-based capital, Tier I leverage ratio and Common Equity tier I as set forth in the table below: Actual Minimum Capital Required - Basel III Phase-In Schedule Minimum Capital Required - Basel III Fully Phased-In Required to be Considered Well Capital Ratio Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2015 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 682,199 12.25 % $ 445,650 8.00 % $ 584,915 10.50 % $ 557,062 10.00 % First Commonwealth Bank 656,244 11.78 445,642 8.00 584,905 10.50 557,052 10.00 Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 626,939 11.25 % $ 334,237 6.00 % $ 473,503 8.50 % $ 445,650 8.00 % First Commonwealth Bank 600,984 10.79 334,231 6.00 473,494 8.50 445,642 8.00 Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 626,939 9.85 % $ 254,631 4.00 % $ 254,631 4.00 % $ 318,289 5.00 % First Commonwealth Bank 600,984 9.46 254,095 4.00 254,095 4.00 317,618 5.00 Common Equity Tier I to Risk Weighted Assets First Commonwealth Financial Corporation $ 556,939 10.00 % $ 250,678 4.50 % $ 389,944 7.00 % $ 362,091 6.50 % First Commonwealth Bank 535,814 9.62 250,673 4.50 389,937 7.00 362,084 6.50 At December 31, 2014, First Commonwealth and First Commonwealth Bank met all capital adequacy requirements to which they were subject. The following table presents actual and required capital ratios as of December 31, 2014 under the regulatory capital rules then in effect. Actual Regulatory Minimum Well Capitalized Regulatory Guidelines Capital Ratio Capital Ratio Capital Ratio (dollars in thousands) As of December 31, 2014 Total Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 662,733 12.79 % $ 414,460 8.00 % N/A N/A First Commonwealth Bank 647,500 12.48 415,217 8.00 $ 519,021 10.00 % Tier I Capital to Risk Weighted Assets First Commonwealth Financial Corporation $ 607,602 11.73 % $ 207,230 4.00 % N/A N/A First Commonwealth Bank 592,369 11.41 207,608 4.00 $ 311,413 6.00 % Tier I Capital to Average Assets First Commonwealth Financial Corporation $ 607,602 9.85 % $ 246,738 4.00 % N/A N/A First Commonwealth Bank 592,369 9.66 245,276 4.00 $ 306,595 5.00 %

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Summary of Net Assets Acquired and Consideration Transferred	The table below summarizes the net assets acquired (at fair value) and consideration transferred in connection with the First Community acquisition: Consideration Paid Cash Paid to shareholders $ 14,750 Total consideration paid 14,750 Fair Value of Assets Acquired Cash and cash equivalents 11,217 Investment Securities 25,980 FHLB Stock 832 Loans 61,173 Premises and other equipment 1,801 Core deposit intangible 172 Other real estate 816 Other assets 1,115 Total assets acquired 103,106 Fair Value of Liabilities Assumed Deposits 90,311 Other Liabilities 1,115 Total liabilities assumed 91,426 Total Fair Value of Identifiable Net Assets 11,680 Goodwill $ 3,070

Condensed Financial Informati60

Condensed Financial Information of First Commonwealth Financial Corporation (parent company only) (Tables)	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Statements of Financial Condition	Statements of Financial Condition December 31, 2015 2014 (dollars in thousands) Assets Cash $ 10,003 $ 10,402 Loans 22 24 Investment in subsidiaries 719,073 712,610 Investment in unconsolidated subsidiary trusts 2,182 2,182 Investment in jointly-owned company 8,978 8,749 Premises and equipment, net 3,780 4,287 Receivable from subsidiaries 441 — Dividends receivable from subsidiaries 714 — Other assets 47,631 50,988 Total assets $ 792,824 $ 789,242 Liabilities and Shareholders’ Equity Accrued expenses and other liabilities $ 1,111 $ 930 Subordinated debentures payable 72,167 72,167 Shareholders’ equity 719,546 716,145 Total liabilities and shareholders’ equity $ 792,824 $ 789,242
Statements of Operations	Statements of Income For the years ended December 31, 2015 2014 2013 (dollars in thousands) Interest and dividends $ 1 $ 1 $ 1 Dividends from subsidiaries 49,917 49,207 65,140 Interest expense (2,357 ) (2,335 ) (3,128 ) Other income 232 1,251 2,653 Operating expense (4,989 ) (6,766 ) (8,820 ) Income (loss) before taxes and equity in undistributed (loss) earnings of subsidiaries 42,804 41,358 55,846 Applicable income tax benefits 2,528 2,968 3,384 Income before equity in undistributed (loss) earnings of subsidiaries 45,332 44,326 59,230 Equity in undistributed earnings (loss) of subsidiaries 4,811 127 (17,748 ) Net income $ 50,143 $ 44,453 $ 41,482
Statements of Cash Flow	For the years ended December 31, Statements of Cash Flow 2015 2014 2013 (dollars in thousands) Operating Activities Net income $ 50,143 $ 44,453 $ 41,482 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 493 2,150 3,030 Net gain (loss) on sales of assets 240 — 17 (Increase) decrease in prepaid income taxes (6,993 ) (487 ) 3,044 Undistributed equity in subsidiaries (4,811 ) (127 ) 17,748 Other net 10,753 13,077 12,964 Net cash provided by operating activities 49,825 59,066 78,285 Investing Activities Net change in loans 2 3 4 Purchases of premises and equipment 54 (47 ) (123 ) Proceeds from sale of other assets — 13 1,132 Net cash (used in) provided by investing activities 56 (31 ) 1,013 Financing Activities Repayments of subordinated debenture — — (34,702 ) Discount on dividend reinvestment plan purchases — (65 ) (112 ) Dividends paid (25,089 ) (26,174 ) (22,344 ) Proceeds from reissuance of treasury stock 192 192 176 Purchase of treasury stock (25,383 ) (30,956 ) (33,439 ) Net cash used in financing activities (50,280 ) (57,003 ) (90,421 ) Net increase (decrease) in cash (399 ) 2,032 (11,123 ) Cash at beginning of year 10,402 8,370 19,493 Cash at end of year $ 10,003 $ 10,402 $ 8,370

Statement of Accounting Polic61

Statement of Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015USD ($)countySegment	Dec. 31, 2014USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of counties in which entity provides services | county	15
Business segments | Segment	1
Equity investments	20.00%
Loans past due days	90 days
Excess impaired credits	$ 100,000
Software purchases and developed are capitalized and amortized on straight-line basis	7 years
Future death benefit [Member]
Summary Of Significant Accounting Policies [Line Items]
Other liabilities	$ 3,700,000	$ 3,900,000

Supplemental Comprehensive In62

Supplemental Comprehensive Income Disclosures - Related Tax Effects Allocated to Each Component of Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Comprehensive Income Disclosures [Abstract]
Unrealized holding (losses) gains on securities arising during the period, Pretax Amount	$ 2,798	$ 25,153	$ (34,975)
Less: reclassification adjustment for (gains) losses on securities included in net income, Pretax Amount	153	(550)	1,158
Total Unrealized (Losses) Gains on Securities, before Tax	2,951	24,603	(33,817)
Unrealized holding gains on derivatives arising during the period, Pretax Amount	450	472	0
Reclassification adjustment for gains on derivatives included in net income, Pretax Amount	49	10	0
Total unrealized gains on derivatives, Pretax Amount	401	462	0
Unrealized holding gains on derivatives arising during the period, Tax (Expense) Benefit	(158)	(165)	0
Reclassification adjustment for gains on derivatives included in net income, Tax (Expense) Benefit	17	3	0
Total unrealized gains on derivatives, Tax (Expense) Benefit	(141)	(162)	0
Unrealized holding gains on derivatives arising during the period, Net of Tax Amount	292	307	0
Reclassification adjustment for gains on derivatives included in net income, Tax (Expense) Benefit	(32)	(7)	0
Total unrealized gains on derivatives, Tax (Expense) Benefit	260	300	0
Transition obligation	0	0	0
Net (loss) gain, Pretax Amount	(102)	(313)	219
Total Unrealized Gains (Losses) for Postretirement Obligations, Before Tax	(102)	(313)	219
Total other comprehensive (loss) income, Pretax Amount	3,250	24,752	(33,598)
Unrealized holding (losses) gains on securities arising during the period, Tax (Expense) Benefit	(978)	(8,803)	12,233
Less: reclassification adjustment for (gains) losses on securities included in net income, Tax (Expense) Benefit	(54)	193	(405)
Total Unrealized (Losses) Gains on Securities, Tax (Expense) Benefit	(1,032)	(8,610)	11,828
Transition obligation, Tax (Expense) Benefit	0	0	0
Net (loss) gain, Tax (Expense) Benefit	36	109	(77)
Total Unrealized Gains (Losses) for Postretirement Obligations, Tax (Expense) Benefit	36	109	(77)
Total other comprehensive (loss) income, Tax (Expense) Benefit	(1,137)	(8,663)	11,751
Unrealized holding (losses) gains on securities arising during the period, Net of Tax Amount	1,820	16,350	(22,742)
Less: reclassification adjustment for (gains) losses on securities included in net income, Net of Tax Amount	99	(357)	753
Total Unrealized (Losses) Gains on Securities, Net of Tax	1,919	15,993	(21,989)
Transition obligation, Net of Tax Amount	0	0	0
Net gain	(66)	(204)	142
Total Unrealized Gains (Losses) for Postretirement Obligations, Net of Tax	(66)	(204)	142
Total other comprehensive (loss) Income	$ 2,113	$ 16,089	$ (21,847)

Supplemental Comprehensive In63

Supplemental Comprehensive Income Disclosures Supplemental Comprehensive Income Disclosures (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	$ (4,499)	$ (20,588)	$ 1,259
Other comprehensive income before reclassification adjustment	2,112	16,657	(22,742)
Amounts reclassified from accumulated other comprehensive income (loss)	67	(364)	753
Net gain	(66)	(204)	142
Net other comprehensive income during the period	2,113	16,089	(21,847)
Balance at end of period	(2,386)	(4,499)	(20,588)
Securities Available for Sale
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	(4,875)	(20,868)	1,121
Other comprehensive income before reclassification adjustment	1,820	16,350	(22,742)
Amounts reclassified from accumulated other comprehensive income (loss)	99	(357)	753
Net other comprehensive income during the period	1,919	15,993	(21,989)
Balance at end of period	(2,956)	(4,875)	(20,868)
Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	300	0	0
Other comprehensive income before reclassification adjustment	292	307	0
Amounts reclassified from accumulated other comprehensive income (loss)	(32)	(7)	0
Net other comprehensive income during the period	260	300	0
Balance at end of period	560	300	0
Post-Retirement Obligation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period	76	280	138
Net gain	(66)	(204)	142
Net other comprehensive income during the period	(66)	(204)	142
Balance at end of period	$ 10	$ 76	$ 280

Supplemental Cash Flow Disclo64

Supplemental Cash Flow Disclosures - Non-cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash paid during the year for:
Interest	$ 15,818	$ 18,943	$ 23,022
Income taxes	8,331	10,700	3,080
Non-cash investing and financing activities:
Loans transferred to other real estate owned and repossessed assets	8,257	5,061	12,326
Other Real Estate Owned and Settled Out of Period	0	0	348
Fair value of loans transferred from held to maturity to available for sale	3,196	3,035	20,135
Gross (decrease) increase in market value adjustment to securities available for sale	2,949	24,601	(33,792)
Gross increase in market value adjustment to derivatives	401	472	0
Investments committed to purchase, not settled	694	0	0
Net assets acquired through acquisition	463	0	0
Contribution of premises	$ 0	$ 682	$ 0

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Weighted average common shares issued	105,563,455	105,563,455	105,563,455
Average treasury shares	(16,045,900)	(12,294,217)	(8,363,083)
Average unearned nonvested shares	(160,788)	(154,584)	(172,215)
Weighted average common shares and common stock equivalents used to calculate basic earnings per share	89,356,767	93,114,654	97,028,157
Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share	0	0	1,675
Weighted average common shares and common stock equivalents used to calculate diluted earnings per share	89,356,767	93,114,654	97,029,832

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	$ 1	$ 1
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	0	15,000	27,000
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, shares	92,002	106,977	81,770
Minimum [Member] | Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	$ 0	$ 14.55	$ 14.41
Minimum [Member] | Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	6.82	5.26	4.41
Maximum [Member] | Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	0	14.55	14.55
Maximum [Member] | Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock, par value (in dollars per share)	$ 9.84	$ 9.26	$ 7.57

Cash and Due from Banks - Addit

Cash and Due from Banks - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Cash and Due from Banks [Abstract]
Cash or balances held with the Federal Reserve Bank	$ 4.6	$ 4.9

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Derivative	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Derivative [Line Items]
Number of participation agreements for interest rate swaps, participant | Derivative	16
Number of participation agreements for interest rate swaps, lead bank | Derivative	4
Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain on derivatives	$ 2,049	$ 330	$ 0
Interest rate swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Number of interest rate swap contracts | Derivative	4
Derivative, notional amount	$ 200,000
Interest rate swap [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount	200,000	$ 100,000
Maturity in three years | Interest rate swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, notional amount	85,000
Maturity in four years | Interest rate swap [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, notional amount	$ 115,000

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, 2015	Dec. 31, 2014
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Credit value adjustment	$ (542)	$ (268)
Not Designated as Hedging Instrument [Member] | Interest rate swap [Member]
Derivative [Line Items]
Derivative, notional amount	276,860	273,388
Not Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, notional amount	22,793	6,656
Not Designated as Hedging Instrument [Member] | Credit Default Swap, Buying Protection [Member]
Derivative [Line Items]
Derivative, notional amount	126,612	113,624
Not Designated as Hedging Instrument [Member] | Credit Default Swap, Selling Protection [Member]
Derivative [Line Items]
Derivative, Sold Protection Notional Amount	(20,383)	(17,296)
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Fair value adjustment	922	472
Designated as Hedging Instrument [Member] | Interest rate swap [Member]
Derivative [Line Items]
Derivative, notional amount	$ 200,000	$ 100,000

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives	$ (274)	$ (345)	$ 1,428
Other Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives	64	10	0
Interest Income [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives	$ 2,049	$ 330	$ 0

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, 2015	Dec. 31, 2014
Investment Securities [Line Items]
Amortized Cost	$ 891,111	$ 1,317,318
Gross Unrealized Gains	11,926	16,921
Gross Unrealized Losses	(16,477)	(24,420)
Estimated Fair Value of Available for Sale	886,560	1,309,819
US States and Political Subdivisions Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	27,066	27,058
Gross Unrealized Gains	532	362
Gross Unrealized Losses	0	(43)
Estimated Fair Value of Available for Sale	27,598	27,377
Corporate Securities [Member]
Investment Securities [Line Items]
Amortized Cost	1,897	6,682
Gross Unrealized Gains	422	573
Gross Unrealized Losses	0	0
Estimated Fair Value of Available for Sale	2,319	7,255
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Investment Securities [Line Items]
Amortized Cost	42,239	41,926
Gross Unrealized Gains	916	309
Gross Unrealized Losses	(7,497)	(13,236)
Estimated Fair Value of Available for Sale	35,658	28,999
Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	888,941	1,315,898
Gross Unrealized Gains	11,926	16,921
Gross Unrealized Losses	(16,477)	(24,420)
Estimated Fair Value of Available for Sale	884,390	1,308,399
Mortgage - Backed Securities - Residential [Member] | US Government Agencies Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	20,034	23,344
Gross Unrealized Gains	2,071	2,595
Gross Unrealized Losses	(13)	(3)
Estimated Fair Value of Available for Sale	22,092	25,936
Mortgage - Backed Securities - Residential [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	778,476	947,635
Gross Unrealized Gains	7,983	13,076
Gross Unrealized Losses	(8,882)	(9,830)
Estimated Fair Value of Available for Sale	777,577	950,881
Mortgage - Backed Securities - Commercial [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	28	72
Gross Unrealized Gains	0	2
Gross Unrealized Losses	0	0
Estimated Fair Value of Available for Sale	28	74
Other Government - Sponsored Enterprises [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	19,201	269,181
Gross Unrealized Gains	2	4
Gross Unrealized Losses	(85)	(1,308)
Estimated Fair Value of Available for Sale	19,118	267,877
Equity Securities [Member]
Investment Securities [Line Items]
Amortized Cost	2,170	1,420
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value of Available for Sale	$ 2,170	$ 1,420

Investment Securities - Additio

Investment Securities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Maturity of contract	less than one year
Approximate year of maturity	30 years
Gross Unrealized Gains (Losses)	$ 16,477	$ 24,420
Securities available for sale	886,560	1,309,819
Amortized Cost	891,111	1,317,318
Gain (loss) on sales of securities	(153)	550	$ (1,158)
Available-for-sale securities pledged as collateral	416,100	563,200
Held-to-maturity securities pledged as collateral	45,700
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Gains (Losses)	500	$ 1,300
Amortized Cost	6,600
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Sale of available securities	75,000
Gain (loss) on sales of securities	$ (300)

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale (Detail) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Investment Securities [Line Items]
Due within 1 year, Amortized Cost		$ 2,601
Due after 1 but within 5 years, Amortized Cost		16,600
Due after 5 but within 10 years, Amortized Cost		27,066
Due after 10 years, Amortized Cost		44,136
Debt securities gross, Amortized Cost		90,403
Amortized Cost		891,111	$ 1,317,318
Total debt securities, Amortized Cost		888,941
Due within 1 year, Estimated Fair Value		2,595
Due after 1 but within 5 years, Estimated Fair Value		16,523
Due after 5 but within 10 years, Estimated Fair Value		27,598
Due after 10 years, Estimated Fair Value		37,977
Debt securities gross, Estimated Fair Value		84,693
Estimated Fair Value of Available for Sale		886,560	$ 1,309,819
Total debt securities, Estimated Fair Value		884,390
Mortgage-Backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost	[1]	798,538
Estimated Fair Value of Available for Sale	[1]	$ 799,697
[1]	Mortgage Backed Securities include an amortized cost of $20.0 million and a fair value of $22.1 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $778.5 million and a fair value of $777.6 million

Investment Securities - Amort74

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale, Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investment Securities [Line Items]
Amortized Cost	$ 891,111	$ 1,317,318
Estimated Fair Value of Available for Sale	886,560	$ 1,309,819
US Government Agencies Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	20,000
Estimated Fair Value of Available for Sale	22,100
Obligations of U.S. Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	778,500
Estimated Fair Value of Available for Sale	$ 777,600

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Proceeds from sale	$ 88,054	$ 132,868	$ 671
Sales Transactions:
Gross gains	0	291	233
Gross losses	(284)	(243)	0
Total gain (losses) from sales transactions	(284)	48	233
Maturities, calls and impairment:
Gross gains	131	502	4
Gross losses	0	0	(1,395)
Other-than-temporary impairment	0	0	0
Total gain (losses) maturities and impairment	131	502	(1,391)
Net gains (losses) and impairment	$ (153)	$ 550	$ (1,158)

Investment Securities - Amort76

Investment Securities - Amortized Cost and Fair Values of Debt Securities Held to Maturity (Details) $ in Thousands	Dec. 31, 2015USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 384,324
Gross Unrealized Gains	331
Gross Unrealized Losses	(2,314)
Estimated Fair Value	382,341
Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	31,910
Gross Unrealized Gains	301
Gross Unrealized Losses	(58)
Estimated Fair Value	32,153
Mortgage - Backed Securities - Residential [Member] | US Government Agencies Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	4,775
Gross Unrealized Gains	0
Gross Unrealized Losses	(7)
Estimated Fair Value	4,768
Mortgage - Backed Securities - Residential [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	315,609
Gross Unrealized Gains	30
Gross Unrealized Losses	(1,824)
Estimated Fair Value	313,815
Mortgage - Backed Securities - Commercial [Member] | US Government Agencies Debt Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	16,843
Gross Unrealized Gains	0
Gross Unrealized Losses	(247)
Estimated Fair Value	16,596
Mortgage - Backed Securities - Commercial [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	15,187
Gross Unrealized Gains	0
Gross Unrealized Losses	(178)
Estimated Fair Value	$ 15,009

Investment Securities - Schedul

Investment Securities - Schedule of Debt Securities Expected Maturity (Details) $ in Thousands	Dec. 31, 2015USD ($)
Amortized Cost
Due within 1 year	$ 0
Due after 1 but within 5 years	108
Due after 5 but within 10 years	27,224
Due after 10 years	4,578
Amortized Cost	31,910
Held-to-maturity Securities	384,324
Estimated Fair Value
Due within 1 year	0
Due after 1 but within 5 years	108
Due after 5 but within 10 years	27,487
Due after 10 years	4,558
Estimated Fair Value	32,153
Securities held to maturity, fair value	382,341
Mortgage-Backed Securities [Member]
Amortized Cost
Held-to-maturity Securities	352,414	[1]
Estimated Fair Value
Securities held to maturity, fair value	350,188	[1]
Mortgage-Backed Securities [Member] | US Government Agencies Debt Securities [Member]
Amortized Cost
Held-to-maturity Securities	21,600
Estimated Fair Value
Securities held to maturity, fair value	21,400
Mortgage-Backed Securities [Member] | US Government-sponsored Enterprises Debt Securities [Member]
Amortized Cost
Held-to-maturity Securities	330,800
Estimated Fair Value
Securities held to maturity, fair value	$ 328,800
[1]	Mortgage Backed Securities include an amortized cost of $21.6 million and a fair value of $21.4 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $330.8 million and a fair value of $328.8 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.

Impairment of Investment Secu78

Impairment of Investment Securities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015USD ($)SecurityBank	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost	$ 891,111,000	$ 1,317,318,000
Estimated Fair Value of Available for Sale	$ 886,560,000	1,309,819,000
Number of banks and other financial institutions comprising the security | Bank	275
Number Of Pooled Securities with No Senior Class | Security	3
Number of Securities with No Excess Subordination | Security	4
Number of Securities with Excess Subordination | Security	5
Collateral issued by financial institutions	$ 15,000,000,000
Coupon interest rate	7.00%
Prepayment rate	5.00%
Estimate of future cash flows prepayment percentage in year three	40.00%
Estimate of future cash flows prepayment percentage thereafter	2.00%
Fair Value Input Coupon Rates	10.00%
Probability of default	100.00%
Projected recovery rate	0.00%
Probability percentage assigned to default bank subject to market indicators	10.00%
Probability percentage assigned to default bank	100.00%
Other than-temporary impairment charge	$ 218,000	0	$ 13,356,000
Net securities (losses) gains	(153,000)	550,000	(1,158,000)
Other investments	$ 62,952,000	44,545,000
Minimum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Subordinated tranches range	7.00%
Total principal amount of the respective securities	5.00%
Excess subordination as a percentage of current performing collateral	10.00%
Collateral issued by financial institutions	$ 15,000,000,000
Probabilities for performing collateral range	0.33%
Excess percent value of future cash flows over current book value	20.00%
Over Fifteen Million [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Prepayment rate	100.00%
Maximum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Subordinated tranches range	35.00%
Excess subordination as a percentage of current performing collateral	84.00%
Collateral issued by financial institutions	$ 2,000,000,000
Probabilities for performing collateral range	75.00%
Excess percent value of future cash flows over current book value	133.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total unrealized losses	40.00%
Corporate/Mortgage-Backed Securities, Amortized cost	$ 42,239,000	41,926,000
Estimated Fair Value of Available for Sale	35,658,000	28,999,000
Other than-temporary impairment charge	$ 0	0	$ 0
Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total unrealized losses	59.00%
Corporate Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost	$ 1,897,000	6,682,000
Estimated Fair Value of Available for Sale	$ 2,319,000	7,255,000
US States and Political Subdivisions Debt Securities [Member] | Other Government - Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total unrealized losses	1.00%
Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Number of securities in an unrealized loss positions | Security	80
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Number of securities in an unrealized loss positions | Security	0
Corporate/Mortgage-Backed Securities, Amortized cost	$ 2,170,000	1,420,000
Estimated Fair Value of Available for Sale	2,170,000	$ 1,420,000
Mm Comm Ix [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other than-temporary impairment charge	13,400,000
Corporate Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost	6,600,000
Net securities (losses) gains	$ 1,300,000
Trust preferred collateralized debt obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Percentage of Current Performing Collateral	0.00%

Impairment of Investment Secu79

Impairment of Investment Securities - Schedule of Unrealized Losses and Estimated Fair Values (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	$ 493,938	$ 229,583
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(3,881)	(694)
Estimated Fair Value, 12 Months or More	293,076	523,463
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	(14,910)	(23,726)
Total Estimated Fair Value	787,014	753,046
Total Gross Unrealized Losses	(18,791)	(24,420)
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	0	0
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	0	0
Estimated Fair Value, 12 Months or More	29,957	24,356
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	(7,497)	(13,236)
Total Estimated Fair Value	29,957	24,356
Total Gross Unrealized Losses	(7,497)	(13,236)
Obligations of U.S. Government [Member] | Mortgage - Backed Securities - Residential [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	6,798	2,318
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(20)	(3)
Estimated Fair Value, 12 Months or More	0	0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	0
Total Estimated Fair Value	6,798	2,318
Total Gross Unrealized Losses	(20)	(3)
Obligations of U.S. Government [Member] | Mortgage - Backed Securities - Commercial [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	16,596
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(247)
Estimated Fair Value, 12 Months or More	0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0
Total Estimated Fair Value	16,596
Total Gross Unrealized Losses	(247)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage - Backed Securities - Residential [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	436,011	111,646
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(3,293)	(419)
Estimated Fair Value, 12 Months or More	263,119	368,706
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	(7,413)	(9,411)
Total Estimated Fair Value	699,130	480,352
Total Gross Unrealized Losses	(10,706)	(9,830)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage - Backed Securities - Commercial [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	15,009
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(178)
Estimated Fair Value, 12 Months or More	0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0
Total Estimated Fair Value	15,009
Total Gross Unrealized Losses	(178)
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	12,316	112,473
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(85)	(229)
Estimated Fair Value, 12 Months or More	0	130,401
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	(1,079)
Total Estimated Fair Value	12,316	242,874
Total Gross Unrealized Losses	(85)	(1,308)
US States and Political Subdivisions Debt Securities [Member] | Other Government - Sponsored Enterprises [Member]
Schedule Of Unrealized Losses On Securities [Line Items]
Estimated Fair Value, Less Than 12 Months	7,208	3,146
Available For Sale Securities Continuous Unrealized Income Loss Position Less Than Twelve Months Aggregate Gain Losses	(58)	(43)
Estimated Fair Value, 12 Months or More	0	0
SecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses	0	0
Total Estimated Fair Value	7,208	3,146
Total Gross Unrealized Losses	$ (58)	$ (43)

Impairment of Investment Secu80

Impairment of Investment Securities - Pooled Trust Preferred Collateralized Debt Obligations (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Bank	Dec. 31, 2014USD ($)
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 891,111	$ 1,317,318
Estimated Fair Value of Available for Sale	886,560	$ 1,309,819
Mezzanine [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	42,239
Estimated Fair Value of Available for Sale	35,658
Unrealized Gain (Loss)	(6,581)
Mezzanine [Member] | Pre TSL IV [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	1,830
Estimated Fair Value of Available for Sale	1,336
Unrealized Gain (Loss)	$ (494)
Debt Instrument, Credit Rating	B1/BB
Number of Banks | Bank	6
Deferrals and Defaults as a % of Current Collateral	18.05%
Excess Subordination as a % of Current Performing Collateral	59.91%
Mezzanine [Member] | Pre TSL VII [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 2,963
Estimated Fair Value of Available for Sale	3,484
Unrealized Gain (Loss)	$ 521
Debt Instrument, Credit Rating	Ca/-
Number of Banks | Bank	14
Deferrals and Defaults as a % of Current Collateral	49.68%
Excess Subordination as a % of Current Performing Collateral	0.00%
Mezzanine [Member] | Pre TSL VIII [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 2,000
Estimated Fair Value of Available for Sale	1,863
Unrealized Gain (Loss)	$ (137)
Debt Instrument, Credit Rating	C/C
Number of Banks | Bank	29
Deferrals and Defaults as a % of Current Collateral	56.74%
Excess Subordination as a % of Current Performing Collateral	0.00%
Mezzanine [Member] | Pre TSL IX [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 2,376
Estimated Fair Value of Available for Sale	1,805
Unrealized Gain (Loss)	$ (571)
Debt Instrument, Credit Rating	B1/C
Number of Banks | Bank	38
Deferrals and Defaults as a % of Current Collateral	29.80%
Excess Subordination as a % of Current Performing Collateral	9.90%
Mezzanine [Member] | Pre TSL X [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 1,613
Estimated Fair Value of Available for Sale	1,915
Unrealized Gain (Loss)	$ 302
Debt Instrument, Credit Rating	Caa1/C
Number of Banks | Bank	43
Deferrals and Defaults as a % of Current Collateral	30.66%
Excess Subordination as a % of Current Performing Collateral	0.00%
Mezzanine [Member] | Pre TSL XII [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 5,688
Estimated Fair Value of Available for Sale	4,585
Unrealized Gain (Loss)	$ (1,103)
Debt Instrument, Credit Rating	B3/C
Number of Banks | Bank	66
Deferrals and Defaults as a % of Current Collateral	23.07%
Excess Subordination as a % of Current Performing Collateral	0.00%
Mezzanine [Member] | Pre TSL XIII [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 12,706
Estimated Fair Value of Available for Sale	10,660
Unrealized Gain (Loss)	$ (2,046)
Debt Instrument, Credit Rating	Ba3/C
Number of Banks | Bank	56
Deferrals and Defaults as a % of Current Collateral	11.08%
Excess Subordination as a % of Current Performing Collateral	37.45%
Mezzanine [Member] | Pre TSL XIV [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 12,854
Estimated Fair Value of Available for Sale	9,708
Unrealized Gain (Loss)	$ (3,146)
Debt Instrument, Credit Rating	B1/CC
Number of Banks | Bank	56
Deferrals and Defaults as a % of Current Collateral	19.72%
Excess Subordination as a % of Current Performing Collateral	47.01%
Mezzanine [Member] | MMCap I [Member]
Impairment Of Investment Securities [Line Items]
Amortized Cost	$ 209
Estimated Fair Value of Available for Sale	302
Unrealized Gain (Loss)	$ 93
Debt Instrument, Credit Rating	Ca/C
Number of Banks | Bank	8
Deferrals and Defaults as a % of Current Collateral	58.11%
Excess Subordination as a % of Current Performing Collateral	83.61%

Impairment of Investment Secu81

Impairment of Investment Securities - Cumulative Roll Forward of Credit Losses Recognized in Earnings for Debt Securities Held and Not Intended to be Sold (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning	[1]	$ 26,246	$ 27,543		$ 43,274
Credit losses on debt securities for which other-than-temporary impairment was not previously recognized		0	0		0
Additional credit losses on debt securities for which other-than- temporary impairment was previously recognized		0	0		0
Increases in cash flows expected to be collected, recognized over the remaining life of the security	[2]	(1,177)	(1,297)		(2,375)
Reduction for debt securities called during the period		(218)	0		(13,356)
Balance, ending		$ 24,851	$ 26,246	[1]	$ 27,543	[1]
[1]	The beginning balance represents credit related losses included in other-than-temporary impairment charges recognized on debt securities in prior periods.
[2]	Represents the increase in cash flows recognized either as principal payments or interest income during the period.

Loans and Allowance for Credi82

Loans and Allowance for Credit Losses - Outstanding Balances of Loan (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 4,683,750	$ 4,457,308	$ 4,283,833
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,150,906	1,052,109
Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	220,736	120,785
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,224,465	1,226,344
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,479,000	1,405,256
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 608,643	$ 652,814

Loans and Allowance for Credi83

Loans and Allowance for Credit Losses - Credit Risk Profile by Creditworthiness (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 4,683,750	$ 4,457,308
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	4,549,787	4,317,182
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	47,523
OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		72,370
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	86,440	63,595
Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	4,161
Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	133,963	140,126
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,150,906	1,052,109
Commercial, financial, agricultural and other [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,074,858	983,357
Commercial, financial, agricultural and other [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	11,825
Commercial, financial, agricultural and other [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		32,563
Commercial, financial, agricultural and other [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	64,223	32,028
Commercial, financial, agricultural and other [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	4,161
Commercial, financial, agricultural and other [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	76,048	68,752
Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	220,736	120,785
Real estate construction [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	220,267	112,536
Real estate construction [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	442
Real estate construction [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		8,013
Real estate construction [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	27	236
Real estate construction [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Real estate construction [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	469	8,249
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,224,465	1,226,344
Residential real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,209,606	1,214,920
Residential real estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	5,244
Residential real estate [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		2,315
Residential real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	9,615	9,109
Residential real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Residential real estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	14,859	11,424
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,479,000	1,405,256
Commercial real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	1,436,714	1,353,773
Commercial real estate [Member] | Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	30,012
Commercial real estate [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross		29,479
Commercial real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	12,274	22,004
Commercial real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Commercial real estate [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	42,286	51,483
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	608,643	652,814
Loans to individuals [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	608,342	652,596
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] | OAEM [Member]
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	301	218
Loans to individuals [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	0	0
Loans to individuals [Member] | Total Non-Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 301	$ 218

Loans and Allowance for Credi84

Loans and Allowance for Credit Losses - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2015USD ($)Contractloan	Dec. 31, 2014USD ($)Contract	Dec. 31, 2013USD ($)Contract	Dec. 31, 2012USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses		$ 14,948,000	$ 11,196,000	$ 19,227,000
Charge-offs		18,868,000	17,472,000	$ 35,178,000
Recorded Investment	$ 50,844,000	$ 50,844,000	$ 55,251,000
Number of loans modified | Contract		61	77	82
Total amount of loan modified	10,956,000	$ 10,956,000	$ 15,967,000	$ 7,713,000
Gain (loss) on sale of impaired loans		400,000	77,000
Off balance sheet reserve to nonperforming loans			14,000
Nonaccrual	36,705,000	36,705,000	42,667,000
Loans held for sale	5,763,000	5,763,000	2,502,000
Total gains or losses included in earnings		111,000	77,000
Loans with modification to rate and payment due to amortization		$ 3,700,000	600,000	2,000,000
Minimum days required for conversion of trouble debt to be in default		90 days
Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unfunded commitments related to nonperforming loans	100,000	$ 100,000	46,000
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for credit losses				(5,926,000)
Charge-offs				$ 0
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due		150 days
Local Energy Company [Member] | Nonaccrual Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Chargeoffs of loans	2,000,000
Nonaccrual	3,900,000	$ 3,900,000
Reserve for Off-balance Sheet Activities [Member] | Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Off balance sheet reserve to nonperforming loans	0	0
Loans Held for Sale [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gains or losses included in earnings		$ 0	$ 77,000
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans modified | Contract		32	52	46
Total amount of loan modified	1,575,000	$ 1,575,000	$ 2,062,000	$ 2,316,000
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans modified | Contract		1	1	5
Total amount of loan modified	389,000	$ 389,000	$ 6,000	$ 2,184,000
Manufacturer of Sporting Goods [Member] | Commercial and Industrial Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	3,900,000	3,900,000
Oil and Gas Well Services Company [Member] | Commercial and Industrial Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	7,500,000	$ 7,500,000
Local Energy Company [Member] | Commercial and Industrial Sector [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans modified | loan		2
Total amount of loan modified			$ 2,900,000		$ 2,300,000
Chargeoffs of loans		$ 3,300,000
Nonaccrual	$ 5,600,000	$ 5,600,000

Loans and Allowance for Credi85

Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans by Segment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 - 59 days past due	$ 8,598	$ 13,473
60 - 89 days past due	1,878	2,690
90 days and greater and still accruing	2,455	2,619
Nonaccrual	36,705	42,667
Total past due and nonaccrual	49,636	61,449
Current	4,634,114	4,395,859
Loans	4,683,750	4,457,308	$ 4,283,833
Commercial Financial Agricultural And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 - 59 days past due	364	2,816
60 - 89 days past due	49	213
90 days and greater and still accruing	129	264
Nonaccrual	23,653	27,007
Total past due and nonaccrual	24,195	30,300
Current	1,126,711	1,021,809
Loans	1,150,906	1,052,109
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 - 59 days past due	280	0
60 - 89 days past due	0	1
90 days and greater and still accruing	0	0
Nonaccrual	28	236
Total past due and nonaccrual	308	237
Current	220,428	120,548
Loans	220,736	120,785
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 - 59 days past due	4,175	5,162
60 - 89 days past due	1,055	1,295
90 days and greater and still accruing	1,315	1,077
Nonaccrual	6,500	7,900
Total past due and nonaccrual	13,045	15,434
Current	1,211,420	1,210,910
Loans	1,224,465	1,226,344
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 - 59 days past due	781	1,797
60 - 89 days past due	0	122
90 days and greater and still accruing	65	0
Nonaccrual	6,223	7,306
Total past due and nonaccrual	7,069	9,225
Current	1,471,931	1,396,031
Loans	1,479,000	1,405,256
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30 - 59 days past due	2,998	3,698
60 - 89 days past due	774	1,059
90 days and greater and still accruing	946	1,278
Nonaccrual	301	218
Total past due and nonaccrual	5,019	6,253
Current	603,624	646,561
Loans	608,643	652,814
Commercial Financial Agricultural And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,150,906	1,052,109	1,021,056
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	220,736	120,785	93,289
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,224,465	1,226,344	1,262,718
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,479,000	1,405,256	1,296,472
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 608,643	$ 652,814	$ 610,298

Loans and Allowance for Credi86

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 50,844	$ 55,251
Unpaid Principal Balance	61,835	60,915
Related Allowance	7,045	9,461
Average Recorded Investment	45,458	49,794	$ 78,175
Interest Income Recognized	615	625	679
Commercial, financial, agricultural and other with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	11,344	9,439
Unpaid Principal Balance	15,673	10,937
Average Recorded Investment	17,692	11,536	14,454
Interest Income Recognized	216	133	73
Real estate construction with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	28	236
Unpaid Principal Balance	117	476
Average Recorded Investment	95	1,190	5,923
Interest Income Recognized	0	19	47
Residential real estate with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	9,952	10,773
Unpaid Principal Balance	11,819	12,470
Average Recorded Investment	10,635	11,592	9,280
Interest Income Recognized	172	210	211
Commercial real estate with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	7,562	8,768
Unpaid Principal Balance	9,449	10,178
Average Recorded Investment	7,890	8,830	27,881
Interest Income Recognized	90	98	250
Loans to individuals with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	421	288
Unpaid Principal Balance	507	337
Average Recorded Investment	338	308	255
Interest Income Recognized	4	4	3
Subtotal with no related allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	29,307	29,504
Unpaid Principal Balance	37,565	34,398
Average Recorded Investment	36,650	33,456	57,793
Interest Income Recognized	482	464	584
Commercial, financial, agricultural and other With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	20,132	24,826
Unpaid Principal Balance	22,590	25,583
Related Allowance	6,952	9,304
Average Recorded Investment	7,731	15,797	16,479
Interest Income Recognized	129	143	64
Real estate construction with an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment	0	0	515
Interest Income Recognized	0	0	0
Residential real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	461	367
Unpaid Principal Balance	672	380
Related Allowance	51	56
Average Recorded Investment	403	357	3,200
Interest Income Recognized	0	14	31
Commercial real estate With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	944	554
Unpaid Principal Balance	1,008	554
Related Allowance	42	101
Average Recorded Investment	674	184	188
Interest Income Recognized	4	4	0
Loans to individuals With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Average Recorded Investment	0	0	0
Interest Income Recognized	0	0	0
Subtotal With an allowance recorded [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment	21,537	25,747
Unpaid Principal Balance	24,270	26,517
Related Allowance	7,045	9,461
Average Recorded Investment	8,808	16,338	20,382
Interest Income Recognized	$ 133	$ 161	$ 95

Loans and Allowance for Credi87

Loans and Allowance for Credit Losses - Troubled Debt Restructured Loans and Commitments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Loans and Leases Receivable Disclosure [Abstract]
Accrual status	$ 14,139	$ 12,584	$ 13,495
Nonaccrual status	12,360	16,952	16,980
Total	26,499	29,536	30,475
Unused lines of credit	$ 3,252	$ 4,120	$ 452

Loans and Allowance for Credi88

Loans and Allowance for Credit Losses - Troubled Debt Restructurings Identified During Period (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Contract	Dec. 31, 2014USD ($)Contract	Dec. 31, 2013USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	61	77	82
Extend Maturity	$ 1,754	$ 5,487	$ 4,390
Modify Rate	3,658	732	2,018
Modify Payments	6,440	16,381	3,971
Others		0	0
Total Pre-Modification Outstanding Recorded Investment	11,852	22,600	10,379
Post-Modification Outstanding Recorded Investment	10,956	15,967	7,713
Specific Reserve	$ 1,332	$ 4,665	$ 1,101
Commercial, financial, agricultural and other [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	12	9	14
Extend Maturity	$ 1,751	$ 5,487	$ 3,462
Modify Rate	3,195	0	0
Modify Payments	4,527	14,529	1,677
Others		0	0
Total Pre-Modification Outstanding Recorded Investment	9,473	20,016	5,139
Post-Modification Outstanding Recorded Investment	8,823	13,785	3,104
Specific Reserve	$ 1,330	$ 4,665	$ 906
Residential real estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	32	52	46
Extend Maturity	$ 0	$ 0	$ 347
Modify Rate	296	629	418
Modify Payments	1,414	1,797	2,116
Others		0	0
Total Pre-Modification Outstanding Recorded Investment	1,710	2,426	2,881
Post-Modification Outstanding Recorded Investment	1,575	2,062	2,316
Specific Reserve	$ 2	$ 0	$ 161
Commercial real estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	1	1	5
Extend Maturity	$ 0	$ 0	$ 571
Modify Rate	0	0	1,499
Modify Payments	464	8	145
Others		0	0
Total Pre-Modification Outstanding Recorded Investment	464	8	2,215
Post-Modification Outstanding Recorded Investment	389	6	2,184
Specific Reserve	$ 0	$ 0	$ 34
Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	16	15	17
Extend Maturity	$ 3	$ 0	$ 10
Modify Rate	167	103	101
Modify Payments	35	47	33
Others		0	0
Total Pre-Modification Outstanding Recorded Investment	205	150	144
Post-Modification Outstanding Recorded Investment	169	114	109
Specific Reserve	$ 0	$ 0	$ 0

Loans and Allowance for Credi89

Loans and Allowance for Credit Losses - Restructured Loans that are Considered to be in Default (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan	Dec. 31, 2013USD ($)loan
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loan	3	3	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 97	$ 13	$ 19
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loan	3	2	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 97	$ 7	$ 19
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | loan	0	1	0
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 0	$ 6	$ 0

Loans and Allowance for Credi90

Loans and Allowance for Credit Losses - Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	$ 52,051	$ 54,225	$ 67,187
Charge-offs	(18,868)	(17,472)	(35,178)
Recoveries	2,681	4,102	2,989
Provision for credit losses	14,948	11,196	19,227
Ending Balance	50,812	52,051	54,225
Ending balance: individually evaluated for impaired	7,045	9,461	8,824
Ending balance: collectively evaluated for impaired	43,767	42,590	45,401
Ending balance	4,683,750	4,457,308	4,283,833
Ending balance: individually evaluated for impaired	44,009	48,442	52,595
Ending balance: collectively evaluated for impaired	4,639,741	4,408,866	4,231,238
Commercial, financial, agricultural and other [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	29,627	22,663	19,852
Charge-offs	(11,429)	(8,911)	(18,399)
Recoveries	1,097	734	455
Provision for credit losses	11,740	15,141	20,755
Ending Balance	31,035	29,627	22,663
Ending balance: individually evaluated for impaired	6,952	9,304	7,364
Ending balance: collectively evaluated for impaired	24,083	20,323	15,299
Ending balance	1,150,906	1,052,109	1,021,056
Ending balance: individually evaluated for impaired	30,767	33,332	27,251
Ending balance: collectively evaluated for impaired	1,120,139	1,018,777	993,805
Real estate construction [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	2,063	6,600	8,928
Charge-offs	(8)	(296)	(773)
Recoveries	84	1,340	501
Provision for credit losses	(1,252)	(5,581)	(2,056)
Ending Balance	887	2,063	6,600
Ending balance: individually evaluated for impaired	0	0	94
Ending balance: collectively evaluated for impaired	887	2,063	6,506
Ending balance	220,736	120,785	93,289
Ending balance: individually evaluated for impaired	0	193	3,844
Ending balance: collectively evaluated for impaired	220,736	120,592	89,445
Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	3,664	7,727	5,908
Charge-offs	(1,539)	(3,153)	(1,814)
Recoveries	587	650	1,264
Provision for credit losses	(106)	(1,560)	2,369
Ending Balance	2,606	3,664	7,727
Ending balance: individually evaluated for impaired	51	56	1,282
Ending balance: collectively evaluated for impaired	2,555	3,608	6,445
Ending balance	1,224,465	1,226,344	1,262,718
Ending balance: individually evaluated for impaired	6,099	7,127	9,349
Ending balance: collectively evaluated for impaired	1,218,366	1,219,217	1,253,369
Commercial real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	11,881	11,778	22,441
Charge-offs	(1,538)	(1,148)	(10,513)
Recoveries	229	612	136
Provision for credit losses	1,352	639	(286)
Ending Balance	11,924	11,881	11,778
Ending balance: individually evaluated for impaired	42	101	84
Ending balance: collectively evaluated for impaired	11,882	11,780	11,694
Ending balance	1,479,000	1,405,256	1,296,472
Ending balance: individually evaluated for impaired	7,143	7,790	12,151
Ending balance: collectively evaluated for impaired	1,471,857	1,397,466	1,284,321
Loans to individuals [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	4,816	5,457	4,132
Charge-offs	(4,354)	(3,964)	(3,679)
Recoveries	684	766	633
Provision for credit losses	3,214	2,557	4,371
Ending Balance	4,360	4,816	5,457
Ending balance: individually evaluated for impaired	0	0	0
Ending balance: collectively evaluated for impaired	4,360	4,816	5,457
Ending balance	608,643	652,814	610,298
Ending balance: individually evaluated for impaired	0	0	0
Ending balance: collectively evaluated for impaired	$ 608,643	652,814	610,298
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		$ 0	5,926
Charge-offs			0
Recoveries			0
Provision for credit losses			(5,926)
Ending Balance			0
Ending balance: individually evaluated for impaired			0
Ending balance: collectively evaluated for impaired			$ 0

Commitments and Letters of Cr91

Commitments and Letters of Credit - Notional Amount of Commitments and Letter of Credit Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Commitments to extend credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 1,643,187	$ 1,635,948
Financial standby letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	17,843	36,075
Performance standby letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	26,497	25,915
Commercial letters of credit
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 1,672	$ 2,611

Commitments and Letters of Cr92

Commitments and Letters of Credit - Additional Information (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Notional amount of financial standby letters of credit	$ 5,900,000
Notional amount of performance standby letters of credit	2,600,000
Notional amount of commercial letters of credit	0
Financial instrument of credit risk	200,000	$ 200,000
Unused commitments and letters of credit [Member]
Loss Contingencies [Line Items]
Commitment liability	$ 4,400,000	$ 3,100,000

Premises and Equipment - Schedu

Premises and Equipment - Schedule of Premises and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 197,724	$ 198,241
Less accumulated depreciation and amortization	134,270	133,252
Total premises and equipment	63,454	64,989
Land [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	12,185	12,098
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 77,086	75,873
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
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 14,518	14,229
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	$ 59,463	59,034
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	10 years
Software [Member]
Property, Plant and Equipment [Line Items]
Property plant and equipment, gross	$ 34,472	$ 37,007
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, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Amount paid under sale-leaseback arrangement	$ 262
Gain on sale of branch	$ 297
Sale-leaseback transaction	15 year
Total lease expense	$ 2,900	$ 2,900	$ 4,200
Premises and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation included in noninterest expense	$ 7,200	$ 13,200	$ 10,400

Premises and Equipment - Sche95

Premises and Equipment - Schedule of Future Minimum Rentals (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Premises [Member]
Operating Leased Assets [Line Items]
2,016	$ 3,339
2,017	3,004
2,018	2,809
2,019	2,531
2,020	1,981
Thereafter	10,360
Total	24,024
Equipment [Member]
Operating Leased Assets [Line Items]
2,016	66
2,017	53
2,018	9
2,019	0
2,020	0
Thereafter	0
Total	$ 128

Goodwill and Other Amortizing96

Goodwill and Other Amortizing Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Oct. 01, 2015
Goodwill And Other Intangibles [Line Items]
Goodwill	$ 164,500,000	$ 161,429,000
Increase in goodwill	3,100,000
Impairment charges on goodwill	0	0	$ 0
Total amortization	18,895,000	21,789,000
Amortization of other intangible assets	$ 605,000	631,000	$ 1,064,000
First Community Bank
Goodwill And Other Intangibles [Line Items]
Goodwill				$ 3,070,000
Customer deposit intangibles
Goodwill And Other Intangibles [Line Items]
Core deposits remaining amortization period	9 years 9 months 18 days
Core deposits weighted average amortization period	5 years 1 month 18 days
Customer deposit intangibles | Previous acquisitions
Goodwill And Other Intangibles [Line Items]
Total amortization	$ 3,500,000
Customer deposit intangibles | First Community Bank
Goodwill And Other Intangibles [Line Items]
Total amortization	$ 200,000
Customer list intangible
Goodwill And Other Intangibles [Line Items]
Core deposits weighted average amortization period	13 years 9 months 18 days
Total amortization	$ 276,000	$ 16,000

Goodwill and Other Amortizing97

Goodwill and Other Amortizing Intangible Assets - Summarized Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 20,126	$ 23,454
Accumulated Amortization	(18,895)	(21,789)
Net Intangible Assets	1,231	1,665
Customer Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	19,142	22,470
Accumulated Amortization	(18,619)	(21,773)
Net Intangible Assets	523	697
Customer list intangible
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	984	984
Accumulated Amortization	(276)	(16)
Net Intangible Assets	$ 708	$ 968

Goodwill and Other Amortizing98

Goodwill and Other Amortizing Intangible Assets - Estimated Amortization Expense of Core Deposit Intangibles (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Other Intangibles [Line Items]
2,016	$ 375
2,017	220
2,018	186
2,019	155
2,020	77
Thereafter	218
Net Intangible Assets	1,231	$ 1,665
Customer list intangible
Goodwill And Other Intangibles [Line Items]
2,016	168
2,017	130
2,018	99
2,019	77
2,020	59
Thereafter	175
Net Intangible Assets	708	$ 968
Customer deposit intangibles
Goodwill And Other Intangibles [Line Items]
2,016	207
2,017	90
2,018	87
2,019	78
2,020	18
Thereafter	43
Net Intangible Assets	$ 523

Interest-Bearing Deposits - Com

Interest-Bearing Deposits - Components of Interest-Bearing Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deposits [Abstract]
Interest-bearing demand deposits	$ 86,365	$ 81,851
Savings deposits	2,390,607	2,402,288
Time deposits	602,233	842,345
Total interest-bearing deposits	$ 3,079,205	$ 3,326,484

Interest-Bearing Deposits - Add

Interest-Bearing Deposits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deposits [Abstract]
Interest-bearing demand deposit, money market	$ 580.8	$ 427.7
Certificates of deposit in denominations of $100 thousand or more	157.7	334
Interest expense related to certificates of deposit $100 thousand or greater	$ 1.8	$ 3.7	$ 4.7

Interest-Bearing Deposits - Sch

Interest-Bearing Deposits - Scheduled Maturities of Time Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Interest Bearing Time Deposits In Banks And Securities [Line Items]
Total	$ 602,233	$ 842,345
Certificates of deposit [Member]
Interest Bearing Time Deposits In Banks And Securities [Line Items]
2,016	354,324
2,017	113,391
2,018	45,744
2,019	54,276
2020 and thereafter	34,498
Total	$ 602,233

Short-term Borrowings - Summary

Short-term Borrowings - Summary of Short-Term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Short-term Debt [Line Items]
Ending Balance	$ 1,510,825	$ 1,105,876	$ 626,615
Average Balance	$ 1,252,531	$ 815,393	$ 478,388
Average Rate	0.40%	0.30%	0.26%
Federal funds purchased
Short-term Debt [Line Items]
Ending Balance	$ 4,000	$ 9,000	$ 16,000
Average Balance	$ 14,832	$ 11,691	$ 11,982
Average Rate	0.36%	0.36%	0.36%
Borrowings from FHLB
Short-term Debt [Line Items]
Ending Balance	$ 1,400,000	$ 945,000	$ 478,100
Average Balance	$ 1,117,522	$ 644,651	$ 335,449
Average Rate	0.42%	0.31%	0.27%
Securities sold under agreements to repurchase
Short-term Debt [Line Items]
Ending Balance	$ 106,825	$ 151,876	$ 132,515
Average Balance	$ 120,177	$ 159,051	$ 130,957
Average Rate	0.23%	0.24%	0.25%
Maximum [Member]
Short-term Debt [Line Items]
Ending Balance	$ 1,510,825	$ 1,105,876	$ 626,615
Weighted Average [Member]
Short-term Debt [Line Items]
Average Rate	0.53%	0.30%	0.27%

Short-term Borrowings - Interes

Short-term Borrowings - Interest Expense on Short-Term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	$ 5,018	$ 2,449	$ 1,262
Federal funds purchased
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	54	42	43
Borrowings from FHLB
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	4,684	2,019	893
Securities sold under agreements to repurchase
Interest On Short Term Borrowings [Line Items]
Total interest on short-term borrowings	$ 280	$ 388	$ 326

Subordinated Debentures - Subor

Subordinated Debentures - Subordinated Debentures Outstanding (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Amount	$ 72,167	$ 72,167
First Commonwealth Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Due	Jan. 1, 2034
Subordinated Debentures outstanding, Amount	$ 30,929	30,929
First Commonwealth Capital Trust III [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures outstanding, Due	Jan. 1, 2034
Subordinated Debentures outstanding, Amount	$ 41,238	$ 41,238

Subordinated Debentures - Addit

Subordinated Debentures - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)trust	Dec. 31, 2014
Subordinated Borrowing [Line Items]
Number of trusts | trust	2
First Commonwealth Capital Trust III [Member]
Subordinated Borrowing [Line Items]
Redemption price as percentage of principal amount	100.00%
Deferred finance costs	$ 630
First Commonwealth Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Redemption price as percentage of principal amount	100.00%
Deferred finance costs	$ 471
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, 2015	Dec. 31, 2014
Amount
Long-term debt	$ 9,314	$ 89,459
Borrowings from FHLB [Member]
Amount
2,015		80,142
2,016	563	563
2,017	585	585
2,018	607	607
2,019	631	631
2,020	659
Thereafter		$ 6,931
Thereafter	$ 6,269
2015, Weighted Average Contractual Rate		0.82%
2016, Weighted Average Contractual Rate	3.82%	3.82%
2017, Weighted Average Contractual Rate	3.83%	3.83%
2018, Weighted Average Contractual Rate	3.83%	3.83%
2019, Weighted Average Contractual Rate	3.83%	3.84%
2020, Weighted Average Contractual Rate	3.84%
Thereafter, Weighted Average Contractual Rate		3.81%
Thereafter, Weighted Average Contractual Rate	3.81%
2015, Weighted Average Effective Rate		0.82%
2016, Weighted Average Effective Rate	3.82%	3.82%
2017, Weighted Average Effective Rate	3.83%	3.83%
2016, Weighted Average Effective Rate	3.83%	3.83%
2017, Weighted Average Effective Rate	3.83%	3.84%
2018, Weighted Average Effective Rate	3.84%
Thereafter, Weighted Average Effective Rate		3.81%
Thereafter, Weighted Average Effective Rate	3.81%

Fair Values of Assets and Li107

Fair Values of Assets and Liabilities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Random sample percentage of securities for each quarter	100.00%
Credit loss recognized	$ 0	$ 0	$ 0
Total gains or losses included in earnings	(111,000)	(77,000)
Interest rate swaps transferred into Level 3 from Level 2	0	3,035,000
Corporate securities transferred from Level 3 to Level 2	0	0
Impaired loans considered to be credit risk of non-collection	100,000
Updated appraisal requirement floor	250,000
Other real estate owned	9,398,000	7,197,000
Financial instrument of credit risk	200,000	200,000
Provision for credit losses	14,948,000	11,196,000	$ 19,227,000
Interest rate swap [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Provision for credit losses	900,000
Loans Held for Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or losses included in earnings	0	(77,000)
Interest rate swaps transferred into Level 3 from Level 2	0	3,035,000
Corporate securities transferred from Level 3 to Level 2	0	0
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total gains or losses included in earnings	0	0
Interest rate swaps transferred into Level 3 from Level 2	0	0
Corporate securities transferred from Level 3 to Level 2	$ 0	$ 0

Fair Values of Assets and Li108

Fair Values of Assets and Liabilities - Quantitative Inputs and Assumptions Used in Level 3 Fair Value Measurements (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets	$ 11,273,000	$ 11,186,000
Estimated Fair Value of Available for Sale	886,560,000	1,309,819,000
Total Debt Securities	884,390,000	1,308,399,000
Discounted Cash Flow at Fair Value	2,963,000
Fair Value	$ 966,548,000	1,368,052,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	1.90%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	4.81%
Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	10.00%
Probability of default [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	0.00%
Probability of default [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	100.00%
Probability of default [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	13.38%
Prepayment rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Prepayment rates
Prepayment rates [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	0.00%
Prepayment rates [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	73.28%
Prepayment rates [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	5.07%
Discount rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Discount rates
Counterparty credit risk [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Counterparty credit risk
Gas per MCF [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Gas per MCF
Gas per MCF [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average	$ 2.34
Gas per MCF [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average	$ 3.71
Oil per BBL/d [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Oil per BBL/d
Oil per BBL/d [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average	$ 42.56
Oil per BBL/d [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average	$ 65.13
Option Model [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Option model
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Probability of default [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Probability of default
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discount rates [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	5.25%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discount rates [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	12.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Discounted Cash Flow
Other Investments [Member] | Par Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Par Value
Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 2,859,000
Impaired Loans [Member] | Discount rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unobservable Inputs	Discount rate
Impaired Loans [Member] | Reserve study [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Gas Reserve study
Other Real Estate Owned [Member] | Internal Valuation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Valuation Technique	Internal Valuation
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Assets	$ 0	0
Estimated Fair Value of Available for Sale	37,828,000	30,419,000
Total Debt Securities	35,658,000	28,999,000
Fair Value	37,828,000	30,419,000
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value of Available for Sale	2,170,000	1,420,000
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value of Available for Sale		1,420,000
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Other Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value of Available for Sale	2,170,000
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	10,047,000	7,981,000
Fair Value	53,846,000	53,771,000
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	8,000	153,000
Fair Value	$ 12,828,000	$ 11,079,000

Fair Values of Assets and Li109

Fair Values of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	$ 884,390	$ 1,308,399
Estimated Fair Value of Available for Sale	886,560	1,309,819
Other investments	62,952	44,545
Loans Held for Sale	5,763	2,502
Other Assets	11,273	11,186
Total Assets	966,548	1,368,052
Other Liabilities	10,829	10,671
Total Liabilities	10,829	10,671
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	2,170	1,420
US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	22,092	25,936
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	777,577	950,881
Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	28	74
Obligations of U.S. Government-Sponsored Enterprises [Member] | Other Government - Sponsored Enterprises [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	19,118	267,877
Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	27,598	27,377
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	2,319	7,255
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	35,658	28,999
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Estimated Fair Value of Available for Sale	0	0
Other investments	0	0
Loans Held for Sale	0	0
Other Assets	0	0
Total Assets	0	0
Other Liabilities	0	0
Total Liabilities	0	0
Level 1 [Member] | Equity Securities [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-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	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]
Total Debt Securities	0	0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	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]
Total Debt Securities	0	0
Level 1 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Level 1 [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Level 1 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	848,732	1,279,400
Estimated Fair Value of Available for Sale	848,732	1,279,400
Other investments	62,952	44,545
Loans Held for Sale	5,763	2,502
Other Assets	11,273	11,186
Total Assets	928,720	1,337,633
Other Liabilities	10,829	10,671
Total Liabilities	10,829	10,671
Level 2 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale	0	0
Level 2 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	22,092	25,936
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]
Total Debt Securities	777,577	950,881
Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	28	74
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]
Total Debt Securities	19,118	267,877
Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	27,598	27,377
Level 2 [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	2,319	7,255
Level 2 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	35,658	28,999
Estimated Fair Value of Available for Sale	37,828	30,419
Other investments	0	0
Loans Held for Sale	0	0
Other Assets	0	0
Total Assets	37,828	30,419
Other Liabilities	0	0
Total Liabilities	0	0
Level 3 [Member] | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value of Available for Sale		1,420
Level 3 [Member] | US Government Agencies Debt Securities [Member] | Mortgage-Backed Securities-Residential [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	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]
Total Debt Securities	0	0
Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises [Member] | Mortgage-Backed Securities-Commercial [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	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]
Total Debt Securities	0	0
Level 3 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Level 3 [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	0	0
Level 3 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Debt Securities	$ 35,658	$ 28,999

Fair Values of Assets and Li110

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, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	$ 30,419	$ 24,943
Total gains or losses included in earnings	111	77
Total gains or losses included in other comprehensive income	7,608	7,162
Purchases	750	0
Issuances	0	0
Sales	0	(3,112)
Settlements	(1,060)	(1,686)
Transfers from Level 3	0	0
Transfers into Level 3	0	3,035
Balance, end of period	37,828	30,419
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	28,999	23,523
Total gains or losses included in earnings	111	0
Total gains or losses included in other comprehensive income	7,608	7,162
Purchases	0	0
Issuances	0	0
Sales	0	0
Settlements	(1,060)	(1,686)
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance, end of period	35,658	28,999
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	1,420	1,420
Total gains or losses included in earnings	0	0
Total gains or losses included in other comprehensive income	0	0
Purchases	750	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	2,170	1,420
Loans Held for Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	0	0
Total gains or losses included in earnings	0	77
Total gains or losses included in other comprehensive income	0	0
Purchases	0	0
Issuances	0	0
Sales	0	(3,112)
Settlements	0	0
Transfers from Level 3	0	0
Transfers into Level 3	0	3,035
Balance, end of period	0	0
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance, beginning of period	0	0
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	$ 0	$ 0

Fair Values of Assets and Li111

Fair Values of Assets and Liabilities - Schedule of Assets Measured on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 966,548	$ 1,368,052
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	43,799	45,790
Other real estate owned	10,047	7,981
Total Assets	53,846	53,771
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, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate owned	0	0
Total Assets	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	928,720	1,337,633
Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	30,979	34,864
Other real estate owned	10,039	7,828
Total Assets	41,018	42,692
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	37,828	30,419
Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	12,820	10,926
Other real estate owned	8	153
Total Assets	12,828	11,079
Total Gains (Losses) [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Of Assets On Nonrecurring Basis Net Losses On Impaired Loans	(9,098)	(7,017)
Fair Value Measurement Of Assets On Nonrecurring Basis Net Losses On Other Real Estate Owned	(1,693)	(1,319)
Fair Value Measurement Of Assets On Nonrecurring Basis Net Loss	$ (10,791)	$ (8,336)

Fair Values of Assets and Li112

Fair Values of Assets and Liabilities - Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	$ 66,644,000	$ 72,276,000
Interest-bearing deposits	2,808,000	2,262,000
Securities available for sale	886,560,000	1,309,819,000
Other investments	62,952,000	44,545,000
Loans held for sale	5,763,000	2,502,000
Loans	4,683,750,000	4,457,308,000	$ 4,283,833,000
Deposits	4,195,894,000	4,315,511,000
Short-term borrowings	1,510,825,000	1,105,876,000	$ 626,615,000
Long-term debt	9,314,000	89,459,000
Subordinated debt	72,167,000	72,167,000
Level 1 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Securities available for sale	0	0
Other investments	0	0
Level 2 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Securities available for sale	848,732,000	1,279,400,000
Other investments	62,952,000	44,545,000
Level 3 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Securities available for sale	37,828,000	30,419,000
Other investments	0	0
Carrying Amount [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	66,644,000	72,276,000
Interest-bearing deposits	2,808,000	2,262,000
Securities available for sale	886,560,000	1,309,819,000
Other investments	62,952,000	44,545,000
Loans held for sale	5,763,000	2,502,000
Loans	4,683,750,000	4,457,308,000
Deposits	4,195,894,000	4,315,511,000
Short-term borrowings	1,510,825,000	1,105,876,000
Long-term debt	9,314,000	89,459,000
Subordinated debt	72,167,000	72,167,000
Estimated Fair Value [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	66,644,000	72,276,000
Interest-bearing deposits	2,808,000	2,262,000
Securities available for sale	886,560,000	1,309,819,000
Other investments	62,952,000	44,545,000
Loans held for sale	5,763,000	2,502,000
Loans	4,690,852,000	4,439,766,000
Deposits	4,198,817,000	4,319,997,000
Short-term borrowings	1,510,718,000	1,105,867,000
Long-term debt	9,834,000	90,319,000
Subordinated debt	62,794,000	62,815,000
Estimated Fair Value [Member] | Level 1 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	66,644,000	72,276,000
Interest-bearing deposits	2,808,000	2,262,000
Securities available for sale	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 debt	0	0
Estimated Fair Value [Member] | Level 2 [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	848,732,000	1,279,400,000
Other investments	62,952,000	44,545,000
Loans held for sale	5,763,000	2,502,000
Loans	30,979,000	34,864,000
Deposits	4,198,817,000	4,319,997,000
Short-term borrowings	1,510,718,000	1,105,867,000
Long-term debt	9,834,000	90,319,000
Subordinated debt	0	0
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	37,828,000	30,419,000
Other investments	0	0
Loans held for sale	0	0
Loans	4,659,873,000	4,404,902,000
Deposits	0	0
Short-term borrowings	0	0
Long-term debt	0	0
Subordinated debt	$ 62,794,000	$ 62,815,000

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Provision (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal	$ 8,610	$ 12,661	$ 2,509
State	68	157	68
Total current tax provision	8,678	12,818	2,577
Deferred State and Local Income Tax Expense (Benefit)	12,158	4,862	12,704
Total tax provision (benefit), Amount	$ 20,836	$ 17,680	$ 15,281

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Tax at statutory rate, Amount	$ 24,843	$ 21,747	$ 19,867
Income Tax Reconciliation, Bank Owned Life Insurance Income	(1,894)	(1,926)	(1,939)
Tax-exempt interest income, net, Amount	(2,232)	(2,133)	(2,600)
Tax credits, Amount	(61)	(134)	(144)
Other, Amount	180	126	97
Total tax provision (benefit), Amount	$ 20,836	$ 17,680	$ 15,281
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Tax at statutory rate, Pretax Income	35.00%	35.00%	35.00%
Income from bank owned life insurance, Pretax Income	(3.00%)	(3.00%)	(3.00%)
Tax-exempt interest income, net, Pretax Income	(3.00%)	(4.00%)	(5.00%)
Tax credits, Pretax Income	(0.00%)	(0.00%)	(0.00%)
Other, Pretax Income	0.00%	0.00%	0.00%
Total tax provision (benefit), Pretax Income	29.00%	28.00%	27.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal statutory rate	35.00%	35.00%	35.00%
Annual effective income tax rate, percentage	29.00%	28.00%	27.00%
Net deferred tax asset	$ 36,360	$ 49,654
Alternative minimum tax credit carryforward	$ 5,065	$ 8,627

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets, Gross [Abstract]
Allowance for credit losses	$ 17,784	$ 18,218
Postretirement benefits other than pensions	641	679
Alternative minimum tax credit carryforward	5,065	8,627
Litigation reserve	0	3,000
Unrealized loss on securities available for sale	1,291	2,463
Writedown of other real estate owned	1,087	603
Deferred compensation	2,113	2,246
Accrued interest on nonaccrual loans	1,452	1,059
Other-than-temporary impairment of securities	89	9,239
Depreciation of assets	879	1,127
Accrued incentives	1,629	1,594
Unfunded loan commitment allowance	1,557	1,078
Accrued severance	808	160
Basis difference in assets acquired	417	0
Loan origination fees and costs	141	0
Deferred rent	1,258	969
Other	1,105	1,194
Total deferred tax assets	37,316	52,256
Deferred tax liabilities:
Basis difference in assets acquired	0	(344)
Loan origination fees and costs	0	(1,337)
Income from unconsolidated subsidiary	(619)	(603)
Other	(337)	(318)
Total deferred tax liabilities	(956)	(2,602)
Net deferred tax asset	$ 36,360	$ 49,654

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employer contribution	6.00%
Employee contribution	80.00%
Plan expense	$ 2,700,000	$ 2,600,000	$ 2,600,000
Retirement Plan expense	0	$ 0
Minimum [Member]
Total annual compensation for a calendar year for non-qualified deferred compensation plan	$ 110,000
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, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Service cost	$ 0	$ 0	$ 0
Interest cost on projected benefit obligation	62	62	62
Amortization of transition obligation	0	0	0
Gain amortization	(4)	(29)	(7)
Net periodic benefit cost	$ 58	$ 33	$ 55

Retirement Plans - Schedule 119

Retirement Plans - Schedule of Changes in Benefit Obligations and Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0
Interest cost	62	62	62
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Funded Status at End of Year	1,815	1,822
Unrecognized transition obligation	0	0
Unrecognized net gain	15	117
Amounts recognized in retained earnings	1,830	1,939
Change in Benefit Obligation [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	1,822	1,644
Service cost	0	0
Interest cost	62	62
Amendments	0	0
Actuarial gain	98	284
Net benefits paid	(167)	(168)
Benefit obligation at end of year	1,815	1,822	1,644
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Net benefits paid	(167)	(168)
Change In Plan Assets [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Net benefits paid	(167)	(168)
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	167	168
Net benefits paid	(167)	(168)
Fair value of plan assets at end of year	$ 0	$ 0	$ 0

Retirement Plans - Schedule 120

Retirement Plans - Schedule of Amounts Recognized as Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Amounts Recognized in the Statement of Financial Condition as Other liabilities	$ 1,815	$ 1,822

Retirement Plans - Schedule 121

Retirement Plans - Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	$ (10)	$ (76)	$ (280)
Transition obligation	0	0	0
Total	(10)	$ (76)	$ (280)
Postretirement Benefit Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	(4)
Transition obligation	0
Total	$ (4)

Retirement Plans - Schedule 122

Retirement Plans - Schedule of Weighted-Average Assumptions Used to Determine Benefit Obligation (Detail) - Benefit Obligation [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Periodic Benefit Cost Assumptions [Line Items]
Discount rate	3.88%	3.61%	4.01%
Health care cost trend: Initial	6.25%	6.50%	6.75%
Health care cost trend: Ultimate	4.75%	4.75%	4.75%
Year ultimate reached	2,022	2,022	2,022

Retirement Plans - Schedule 123

Retirement Plans - Schedule of Weighted-Average Assumptions Used to Determine Net Periodic Cost (Detail) - Plans Net Periodic Cost [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Periodic Benefit Cost Assumptions [Line Items]
Discount rate	3.61%	4.01%	3.31%
Health care cost trend: Initial	6.50%	6.75%	7.00%
Health care cost trend: Ultimate	4.75%	4.75%	4.75%
Year ultimate reached	2,022	2,022	2,022
Corridor	10.00%	10.00%	10.00%
Recognition period for gains and losses	11 years	10 years	11 years

Retirement Plans - Schedule 124

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, 2015USD ($)
Compensation and Retirement Disclosure [Abstract]
Effect on total of service and interest cost components, One-Percentage-Point Increase	$ 73
Effect on postretirement benefit obligation, One-Percentage-Point Increase	3
Effect on total of service and interest cost components, One-Percentage-Point Decrease	(66)
Effect on postretirement benefit obligation, One-Percentage-Point Decrease	$ (2)

Retirement Plans - Schedule 125

Retirement Plans - Schedule of Projected Benefit Payments (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2,016	$ 207
2,017	204
2,018	190
2,019	163
2,020	156
2021 - 2025	$ 656

Unearned ESOP Shares (Detail)

Unearned ESOP Shares (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Minimum years for eligibility to participate in ESOP	1 year
Borrowed funds		$ 1.6

Incentive Compensation Plan - A

Incentive Compensation Plan - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Jun. 26, 2015	Feb. 20, 2015	Feb. 20, 2015	Feb. 05, 2015	Jan. 29, 2015	Jan. 15, 2015	Nov. 18, 2014	Apr. 08, 2014	Mar. 25, 2014	Mar. 05, 2014	Jan. 01, 2014	Aug. 16, 2013	May. 31, 2013	Mar. 01, 2013	Jan. 28, 2013	Jan. 02, 2012	Apr. 01, 2011	Feb. 24, 2012	Nov. 21, 2011	Jan. 17, 2011	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Price (in dollars per share)																					$ 8.41	$ 9.03	$ 7.25
Maximum number of shares that are available to be awarded																					5,000,000
Options granted under plan																					$ 4.5
Vesting period of restricted stock															1 year			1 year		1 year	10 years
Options exercised																					0	0	0
Granted, Shares																					0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant																					3,942,531
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Price (in dollars per share)																					$ 9.07
Allocated Share-based Compensation Expense																					$ 1.4
Compensation expense																						$ 1	$ 0.5
Unrecognized compensation cost related to unvested restricted stock																					$ 2.5
Executive [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	1,000	34,200	10,000			20,000	3,500	27,500	46,000	5,000	12,626	3,000	45,000	10,000	128,611,000	100,000	25,000	68,000,000	10,000	54,166,000
Grant Price (in dollars per share)	$ 9.84	$ 8.45	$ 8.45			$ 8.38	$ 9.26	$ 8.89	$ 9.18	$ 8.75	$ 8.82	$ 7.57	$ 7.21	$ 7.35		$ 5.26	$ 6.82		$ 4.41
Vesting Date	Jun. 26, 2018	Dec. 31, 2015	Feb. 20, 2018			Jan. 15, 2017	Nov. 17, 2017	Apr. 8, 2017	Mar. 24, 2017	Mar. 4, 2017	Dec. 31, 2014	Aug. 16, 2016	May 31, 2016	Mar. 1, 2016		Jan. 1, 2016	Apr. 1, 2016		Nov. 21, 2014
Number of Equal Vesting Periods	1	1	1			1	1	3	1	1	1	1	3	1		4	1		1
Executive [Member] | 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														34,000
Grant Price (in dollars per share)				$ 8.55														$ 5.96
Vesting Date				Feb. 5, 2018														Dec. 31, 2014
Number of Equal Vesting Periods				1														1
Executive [Member] | Restricted Stock [Member] | Annual Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)					20,170													90,000
Grant Price (in dollars per share)					$ 7.93													$ 5.96
Vesting Date					Dec. 31, 2015													Feb. 24, 2015
Number of Equal Vesting Periods					1													1

Incentive Compensation Plan - U

Incentive Compensation Plan - Unvested Service-Based Restricted Stock Awards (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	265,000	271,000	253,000
Granted, Shares	135,370	94,626	58,000
Vested, Shares	(168,536)	(98,487)	(35,000)
Forfeited, Shares	0	(2,139)	(5,000)
Outstanding, end of the year, Shares	231,834	265,000	271,000
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	$ 7.08	$ 6.07	$ 5.71
Grant Price (in dollars per share)	8.41	9.03	7.25
Vested, Weighted Average Grant Date Fair Value	6.87	6.18	5.46
Forfeited, Weighted Average Grant Date Fair Value	0	5.96	5.96
Outstanding, end of the year, Weighted Average Grant Date Fair Value	$ 8.01	$ 7.08	$ 6.07

Incentive Compensation Plan Inc

Incentive Compensation Plan Incentive Compensation Plan - Restricted Stock Awards Estimated to be Granted on a Performance Award (Details) - shares	Jun. 26, 2015	Feb. 20, 2015	Feb. 20, 2015	Feb. 05, 2015	Jan. 15, 2015	Nov. 18, 2014	Apr. 08, 2014	Mar. 25, 2014	Mar. 05, 2014	Jan. 01, 2014	Aug. 16, 2013	May. 31, 2013	Mar. 01, 2013	Jan. 28, 2013	Jan. 02, 2012	Apr. 01, 2011	Feb. 24, 2012	Nov. 21, 2011	Jan. 17, 2011	Dec. 31, 2015
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%
Performance Shares Awards As Percentage Of Target														100.00%			100.00%		100.00%
Percentage Of Target Award Opportunities Maximum In Certain Cases														200.00%			200.00%		200.00%
Vesting period of restricted stock														1 year			1 year		1 year	10 years
Performance Based Stock Awards Vesting Period														3 years			3 years		3 years
Restricted Stock [Member] | Executive [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued to executive	1,000	34,200	10,000		20,000	3,500	27,500	46,000	5,000	12,626	3,000	45,000	10,000	128,611,000	100,000	25,000	68,000,000	10,000	54,166,000
Restricted Stock [Member] | Executive [Member] | Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued to executive				50,000													34,000

Incentive Compensation Plan 130

Incentive Compensation Plan - Unvested Target Award (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	265,000	271,000	253,000
Granted, Shares	135,370	94,626	58,000
Vested, Shares	(168,536)	(98,487)	(35,000)
Forfeited, Shares	0	(2,139)	(5,000)
Outstanding, end of the year, Shares	231,834	265,000	271,000
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	284,000	250,777	151,333
Granted, Shares	185,000	126,389	138,611
Vested, Shares	(34,200)	(12,626)	0
Forfeited, Shares	(114,095)	(80,540)	(39,167)
Outstanding, end of the year, Shares	320,705	284,000	250,777

Incentive Compensation Plan - O

Incentive Compensation Plan - Outstanding Stock Options (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of the year, Shares	15,000	27,000	196,322
Granted, Shares	0	0	0
Exercised, Shares	0	0	0
Forfeited, Shares	(15,000)	(12,000)	(169,322)
Balance, end of the year, Shares	0	15,000	27,000
Exercisable at the end of the year, Shares	0	15,000	27,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of the year, Weighted Average Exercise Price	$ 14.55	$ 14.49	$ 11.64
Granted, Weighted Average Exercise Price	0	0	0
Exercised, Weighted Average Exercise Price	0	0	0
Forfeited, Weighted Average Exercise Price	14.55	14.41	11.19
Balance, end of the year, Weighted Average Exercise Price	0	14.55	14.49
Exercisable at the end of the year, Weighted Average Exercise Price	$ 0	$ 14.55	$ 14.49

Contingent Liabilities - Additi

Contingent Liabilities - Additional Information (Detail)	Aug. 27, 2015plaintiff	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | plaintiff	8
Minimum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses		$ 0
Maximum [Member]
Loss Contingencies [Line Items]
Range of reasonably possible losses		$ 5,000,000

Related Party Transactions - Lo

Related Party Transactions - Loans to Related Parties (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Loans and Leases Receivable, Related Parties [Roll Forward]
Beginning balance	$ 722
Advances	740
Repayments	(323)
Ending balance	$ 1,139

Regulatory Restrictions and 134

Regulatory Restrictions and Capital Adequacy - Schedule of Capital Amount and Ratio Considered to be Capitalized (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Common Equity to Risk Weighted Assets	$ 556,939
Tier 1 Common Equity to Risk Weighted Assets	10.00%
Tier 1 Common Equity Required to be Well Capitalized	$ 362,091
Tier 1 Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%
First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 Common Equity to Risk Weighted Assets	$ 535,814
Tier 1 Common Equity to Risk Weighted Assets	9.62%
Tier 1 Common Equity Required to be Well Capitalized	$ 362,084
Tier 1 Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%
Actual | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets	$ 682,199	$ 662,733
Tier I Capital to Risk Weighted Assets	626,939	607,602
Tier I Capital to Average Assets	$ 626,939	$ 607,602
Total Capital to Risk Weighted Assets, Ratio	12.25%	12.79%
Tier I Capital to Risk Weighted Assets, Ratio	11.25%	11.73%
Tier I Capital to Average Assets, Ratio	9.85%	9.85%
Actual | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets	$ 656,244	$ 647,500
Tier I Capital to Risk Weighted Assets	600,984	592,369
Tier I Capital to Average Assets	$ 600,984	$ 592,369
Total Capital to Risk Weighted Assets, Ratio	11.78%	12.48%
Tier I Capital to Risk Weighted Assets, Ratio	10.79%	11.41%
Tier I Capital to Average Assets, Ratio	9.46%	9.66%
Minimum Capital Required - Basel III Phase-In Schedule | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	$ 445,650
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	334,237
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount	254,631
Tier 1 Common Equity Required for Capital Adequacy	$ 250,678
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio	8.00%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio	6.00%
Tier I Capital to Average Assets, Regulatory Minimum Ratio	4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets	4.50%
Minimum Capital Required - Basel III Phase-In Schedule | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	$ 445,642
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	334,231
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount	254,095
Tier 1 Common Equity Required for Capital Adequacy	$ 250,673
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio	8.00%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio	6.00%
Tier I Capital to Average Assets, Regulatory Minimum Ratio	4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets	4.50%
Minimum Capital Required - Basel III Fully Phased-In | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	$ 584,915
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	473,503
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount	254,631
Tier 1 Common Equity Required for Capital Adequacy	$ 389,944
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio	10.50%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio	8.50%
Tier I Capital to Average Assets, Regulatory Minimum Ratio	4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets	7.00%
Minimum Capital Required - Basel III Fully Phased-In | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	$ 584,905
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount	473,494
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount	254,095
Tier 1 Common Equity Required for Capital Adequacy	$ 389,937
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio	10.50%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio	8.50%
Tier I Capital to Average Assets, Regulatory Minimum Ratio	4.00%
Tier 1 Common Equity Required for Capital Adequacy to Risk Weighted Assets	7.00%
Regulatory Minimum | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount		$ 414,460
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount		207,230
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount		$ 246,738
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio		8.00%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio		4.00%
Tier I Capital to Average Assets, Regulatory Minimum Ratio		4.00%
Regulatory Minimum | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount		$ 415,217
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Capital Amount		207,608
Tier I Capital to Average Assets, Regulatory Minimum Capital Amount		$ 245,276
Total Capital to Risk Weighted Assets, Regulatory Minimum Ratio		8.00%
Tier I Capital to Risk Weighted Assets, Regulatory Minimum Ratio		4.00%
Tier I Capital to Average Assets, Regulatory Minimum Ratio		4.00%
Required to be Considered Well Capitalized | First Commonwealth Financial Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	$ 557,062
Tier I Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines, Capital Amount	445,650
Tier I Capital to Average Assets, Well Capitalized Regulatory Guidelines, Capital Amount	$ 318,289
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	10.00%
Tier I Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines Ratio	8.00%
Tier I Capital to Average Assets, Well Capitalized Regulatory Guidelines Ratio	5.00%
Required to be Considered Well Capitalized | First Commonwealth Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	$ 557,052	$ 519,021
Tier I Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines, Capital Amount	445,642	311,413
Tier I Capital to Average Assets, Well Capitalized Regulatory Guidelines, Capital Amount	$ 317,618	$ 306,595
Total Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines	10.00%	10.00%
Tier I Capital to Risk Weighted Assets, Well Capitalized Regulatory Guidelines Ratio	8.00%	6.00%
Tier I Capital to Average Assets, Well Capitalized Regulatory Guidelines Ratio	5.00%	5.00%

Capital - Additional Informatio

Capital - Additional Information (Detail) $ / shares in Units, $ in Millions	12 Months Ended	18 Months Ended
	Dec. 31, 2015program$ / shares	Dec. 31, 2013shares	Jan. 27, 2015shares	Jan. 28, 2014shares	Jan. 29, 2013shares	Jun. 19, 2012USD ($)
Disclosure Capital Additional Information [Abstract]
Announcement of common stock repurchase program | $						$ 50
Number of shares authorized to be repurchased			25,000,000	25,000,000	25,000,000
Number of repurchase programs | program	3
Stock repurchased (in shares)		16,619,205
Average price per share | $ / shares	$ 7.55

Acquisition - Narrative (Detail

Acquisition - Narrative (Details) $ in Thousands	Oct. 01, 2015USD ($)branch	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Business Acquisition [Line Items]
Costs related to the acquisition		$ 922	$ 0	$ 0
First Community Bank
Business Acquisition [Line Items]
Total consideration paid	$ 14,750
Gross loans receivable acquired	62,500
Credit market adjustment of gross loans acquired	1,300
Costs related to the acquisition	$ 900
Number of Stores | branch	4

Acquisition - Summary (Details)

Acquisition - Summary (Details) - USD ($) $ in Thousands	Oct. 01, 2015	Dec. 31, 2015	Dec. 31, 2014
Fair Value of Liabilities Assumed
Goodwill		$ 164,500	$ 161,429
First Community Bank
Consideration Paid
Cash Paid to shareholders	$ 14,750
Total consideration paid	14,750
Fair Value of Assets Acquired
Cash and cash equivalents	11,217
Investment Securities	25,980
FHLB Stock	832
Loans	61,173
Premises and other equipment	1,801
Core deposit intangible	172
Other real estate	816
Other assets	1,115
Total assets acquired	103,106
Fair Value of Liabilities Assumed
Deposits	90,311
Other Liabilities	1,115
Total liabilities assumed	91,426
Total Fair Value of Identifiable Net Assets	11,680
Goodwill	$ 3,070

Condensed Financial Informat138

Condensed Financial Information of First Commonwealth Financial Corporation (Parent Company Only) - Statements of Financial Condition (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Loans	$ 4,632,938	$ 4,405,257
Premises and equipment, net	63,454	64,989
Other assets	103,717	110,777
Total assets	6,566,890	6,360,285
Liabilities and Shareholders' Equity
Subordinated debentures payable	72,167	72,167
Shareholders' equity	719,546	716,145	$ 711,697	$ 746,007
Total liabilities and shareholders’ equity	6,566,890	6,360,285
Parent [Member]
Assets
Cash	10,003	10,402
Loans	22	24
Investment in subsidiaries	719,073	712,610
Investment in unconsolidated subsidiary trusts	2,182	2,182
Investment in Jointly-Owned Company	8,978	8,749
Premises and equipment, net	3,780	4,287
Recievable from subsidiaries	441	0
Dividends receivable from subsidiaries	714	0
Other assets	47,631	50,988
Total assets	792,824	789,242
Liabilities and Shareholders' Equity
Accrued expenses and other liabilities	1,111	930
Subordinated debentures payable	72,167	72,167
Shareholders' equity	719,546	716,145
Total liabilities and shareholders’ equity	$ 792,824	$ 789,242

Condensed Financial Informat139

Condensed Financial Information of First Commonwealth Financial Corporation (Parent Company Only) - Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Interest and dividends	$ 204,071	$ 202,181	$ 206,358
Interest expense	(15,595)	(18,501)	(21,707)
Other income	7,614	7,445	12,060
Applicable income tax (provision) benefits	(20,836)	(17,680)	(15,281)
Net Income	50,143	44,453	41,482
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Interest and dividends	1	1	1
Dividends from subsidiaries	49,917	49,207	65,140
Interest expense	(2,357)	(2,335)	(3,128)
Other income	232	1,251	2,653
Operating expense	(4,989)	(6,766)	(8,820)
Income (loss) before taxes and equity in undistributed earnings of subsidiaries	42,804	41,358	55,846
Applicable income tax (provision) benefits	2,528	2,968	3,384
Income (loss) before equity in undistributed earnings of subsidiaries	45,332	44,326	59,230
Equity in undistributed (loss) earnings of subsidiaries	4,811	127	(17,748)
Net Income	$ 50,143	$ 44,453	$ 41,482

Condensed Financial Informat140

Condensed Financial Information of First Commonwealth Financial Corporation (parent company only) - Statements of Cash Flow (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities
Net Income	$ 50,143	$ 44,453	$ 41,482
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,640	13,721	11,090
Other net	(7,929)	8,253	(2,426)
Net cash provided by operating activities	72,751	82,137	85,734
Investing Activities
Proceeds from sale of other assets	6,407	12,882	12,713
Net cash used in investing activities	(142,433)	(164,055)	(307,280)
Financing Activities
Repayments of subordinated debentures	0	0	(34,702)
Discount on dividend reinvestment plan purchases	0	(65)	(112)
Dividends paid	(25,089)	(26,174)	(22,344)
Proceeds from reissuance of treasury stock	192	192	176
Purchase of treasury stock	(25,383)	(30,956)	(33,439)
Net cash provided by financing activities	64,596	79,017	196,003
Net (decrease) increase in cash and cash equivalents	(5,086)	(2,901)	(25,543)
Cash and cash equivalents at January 1	74,538	77,439	102,982
Cash and cash equivalents at December 31	69,452	74,538	77,439
Parent [Member]
Operating Activities
Net Income	50,143	44,453	41,482
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	493	2,150	3,030
Net gain (loss) on sales of assets	240	0	17
(Increase) decrease in prepaid income taxes	(6,993)	(487)	3,044
Undistributed equity in subsidiaries	(4,811)	(127)	17,748
Other net	10,753	13,077	12,964
Net cash provided by operating activities	49,825	59,066	78,285
Investing Activities
Net change in loans	2	3	4
Payments to Acquire Property and Equipment	54	(47)	(123)
Proceeds from sale of other assets	0	13	1,132
Net cash used in investing activities	56	(31)	1,013
Financing Activities
Repayments of subordinated debentures	0	0	(34,702)
Discount on dividend reinvestment plan purchases	0	(65)	(112)
Dividends paid	(25,089)	(26,174)	(22,344)
Proceeds from reissuance of treasury stock	192	192	176
Purchase of treasury stock	(25,383)	(30,956)	(33,439)
Net cash provided by financing activities	(50,280)	(57,003)	(90,421)
Net (decrease) increase in cash and cash equivalents	(399)	2,032	(11,123)
Cash and cash equivalents at January 1	10,402	8,370	19,493
Cash and cash equivalents at December 31	$ 10,003	$ 10,402	$ 8,370

Condensed Financial Informat141

Condensed Financial Information of First Commonwealth Financial Corporation (Parent Company Only) - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.28	$ 0.28	$ 0.23
Line of credit	$ 15,000,000
Borrowings		$ 0	$ 0

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail)	Feb. 17, 2016USD ($)
Subsequent Event [Member]
Subsequent Event [Line Items]
Additional shares authorized for repurchase	$ 25,000,000