TriCo Bancshares (TCBK) 10-Q 9 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 06, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	TCBK
Entity Registrant Name	TRICO BANCSHARES /
Entity Central Index Key	356,171
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		30,417,818
Entity Emerging Growth Company	false
Entity Small Business	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets:
Cash and due from banks	$ 109,363	$ 105,968
Cash at Federal Reserve and other banks	117,180	99,460
Cash and cash equivalents	226,543	205,428
Investment securities:
Marketable equity securities	2,846	2,938
Available for sale debt securities	1,055,960	727,945
Held to maturity debt securities	459,897	514,844
Restricted equity securities	17,250	16,956
Loans held for sale	3,824	4,616
Loans	4,027,436	3,015,165
Allowance for loan losses	(31,603)	(30,323)
Total loans, net	3,995,833	2,984,842
Foreclosed assets, net	1,832	3,226
Premises and equipment, net	89,290	57,742
Cash value of life insurance	116,596	97,783
Accrued interest receivable	19,592	13,772
Goodwill	220,972	64,311
Other intangible assets, net	30,711	5,174
Mortgage servicing rights	7,122	6,687
Other assets	70,597	55,051
Total assets	6,318,865	4,761,315
Deposits:
Noninterest-bearing demand	1,710,505	1,368,218
Interest-bearing	3,382,612	2,640,913
Total deposits	5,093,117	4,009,131
Accrued interest payable	1,729	930
Other liabilities	82,077	66,422
Other borrowings	282,831	122,166
Junior subordinated debt	56,996	56,858
Total liabilities	5,516,750	4,255,507
Commitments and contingencies (Note 12)
Shareholders' equity:
Preferred stock, no par value: 1,000,000 shares authorized, zero issued and outstanding at September 30, 2018 and December 31, 2017
Common stock, no par value: 50,000,000 shares authorized; issued and outstanding: 30,417,818 at September 30, 2018 22,955,963 at December 31, 2017	541,519	255,836
Retained earnings	287,555	255,200
Accumulated other comprehensive loss, net of tax	(26,959)	(5,228)
Total shareholders' equity	802,115	505,808
Total liabilities and shareholders' equity	$ 6,318,865	$ 4,761,315

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, no par value	$ 0	$ 0
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, no par value	$ 0	$ 0
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	30,417,818	22,955,963
Common stock, shares outstanding	30,417,818	22,955,963

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest and dividend income:
Loans, including fees	$ 53,102	$ 37,268	$ 130,455	$ 108,600
Investments:
Taxable securities	9,189	7,011	23,949	20,617
Tax exempt securities	1,189	1,041	3,272	3,124
Dividends	459	301	1,093	1,020
Interest bearing cash at Federal Reserve and other banks	615	292	1,384	1,080
Total interest and dividend income	64,554	45,913	160,153	134,441
Interest expense:
Deposits	2,072	1,028	4,402	2,896
Other borrowings	1,178	149	2,106	164
Junior subordinated debt	815	652	2,301	1,870
Total interest expense	4,065	1,829	8,809	4,930
Net interest income	60,489	44,084	151,344	129,511
Provision for (benefit from) loan losses	2,651	765	1,777	(1,588)
Net interest income after provision for (benefit from) loan losses	57,838	43,319	149,567	131,099
Noninterest income:
Service charges and fees	9,743	9,475	28,327	27,861
Commissions on sale of non-deposit investment products	728	672	2,414	1,984
Increase in cash value of life insurance	732	732	1,996	2,043
Gain on sale of loans	539	606	1,831	2,293
Gain on sale of investment securities	207	961	207	961
Other	237	484	1,875	2,401
Total noninterest income	12,186	12,930	36,650	37,543
Noninterest expense:
Salaries and related benefits	25,823	20,933	68,928	62,320
Other	21,555	16,289	54,482	46,628
Total noninterest expense	47,378	37,222	123,410	108,948
Income before income taxes	22,646	19,027	62,807	59,694
Provision for income taxes	6,476	7,130	17,698	22,129
Net income	$ 16,170	$ 11,897	$ 45,109	$ 37,565
Earnings per share:
Basic	$ 0.54	$ 0.52	$ 1.78	$ 1.64
Diluted	$ 0.53	$ 0.51	$ 1.76	$ 1.62

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 16,170	$ 11,897	$ 45,109	$ 37,565
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) on available for sale securities arising during the period, after reclassifications	(5,917)	(166)	(20,941)	3,137
Change in minimum pension liability, after reclassifications	81	55	241	164
Other comprehensive income (loss)	(5,836)	(111)	(20,700)	3,301
Comprehensive income	$ 10,334	$ 11,786	$ 24,409	$ 40,866

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2016	$ 477,347	$ 252,820	$ 232,440	$ (7,913)
Beginning balance, shares at Dec. 31, 2016		22,867,802
Net income	37,565		37,565
Other comprehensive income (loss)	3,301			3,301
Stock option vesting	211	$ 211
Service condition RSU vesting	657	657
Market plus service condition RSU vesting	316	316
Service condition RSUs released	0	$ 0	0	0
Service condition RSUs released, shares		28,397
Market plus service condition RSUs released	0	$ 0	0	0
Market plus service conditions RSUs released, shares		18,805
Stock options exercised	2,418	$ 2,418
Stock options exercised, shares		133,850
Repurchase of common stock, value	(3,854)	$ (1,191)	(2,663)
Repurchase of common stock, shares		(107,390)
Dividends paid	(11,228)		(11,228)
Ending balance at Sep. 30, 2017	506,733	$ 255,231	256,114	(4,612)
Ending balance, shares at Sep. 30, 2017		22,941,464
Beginning balance at Dec. 31, 2017	$ 505,808	$ 255,836	255,200	(5,228)
Beginning balance, shares at Dec. 31, 2017	22,955,963	22,955,963
Net income	$ 45,109		45,109
Adoption ASU | ASU 2016-01 [Member]			(62)	62
Adoption ASU | ASU 2018-02 [Member]			1,093	(1,093)
Other comprehensive income (loss)	(20,700)			(20,700)
Stock option vesting	75	$ 75
Service condition RSU vesting	745	745
Market plus service condition RSU vesting	274	274
Service condition RSUs released	0	$ 0	0	0
Service condition RSUs released, shares		32,516
Market plus service condition RSUs released	0	$ 0	0	0
Market plus service conditions RSUs released, shares		25,512
Stock options exercised	$ 475	$ 475
Stock options exercised, shares	27,400	27,400
Issuance of common stock	$ 284,437	$ 284,437
Issuance of common stock, shares		7,405,277
Repurchase of common stock, value	(1,124)	$ (323)	(801)
Repurchase of common stock, shares		(28,850)
Dividends paid	(12,984)		(12,984)
Ending balance at Sep. 30, 2018	$ 802,115	$ 541,519	$ 287,555	$ (26,959)
Ending balance, shares at Sep. 30, 2018	30,417,818	30,417,818

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Retained Earnings [Member]
Dividends paid, per share	$ 0.51	$ 0.49

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income	$ 45,109	$ 37,565
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of premises and equipment, and amortization	4,914	5,089
Amortization of intangible assets	2,068	1,050
Provision for (benefit from) loan losses	1,777	(1,588)
Amortization of investment securities premium, net	1,953	2,431
Gain on sale of investment securities	(207)	(961)
Originations of loans for resale	(63,912)	(83,907)
Proceeds from sale of loans originated for resale	66,138	85,846
Gain on sale of loans	(1,831)	(2,293)
Change in market value of mortgage servicing rights	(38)	795
Provision for losses on foreclosed assets	89	162
Gain on sale of foreclosed assets	(390)	(308)
Loss on disposal of fixed assets	206	61
Gain on sale of premises held for sale		(3)
Increase in cash value of life insurance	(1,996)	(2,043)
Life insurance proceeds in excess of cash value		(108)
Loss on marketable equity securities	92
Equity compensation vesting expense	1,094	1,184
Change in:
Reserve for unfunded commitments	(864)	270
Interest receivable	(5,820)	(629)
Interest payable	799	49
Other assets and liabilities, net	10,724	3,155
Net cash from operating activities	59,905	45,817
Investing activities:
Cash acquired in acquisition, net of consideration paid	30,613
Proceeds from maturities of securities available for sale	54,510	20,889
Proceeds from maturities of securities held to maturity	54,203	64,969
Proceeds from sale of available for sale securities	293,279	25,757
Purchases of securities available for sale	(370,843)	(195,465)
Net redemption of restricted equity securities	7,429
Loan origination and principal collections, net	(178,596)	(174,914)
Proceeds from sale of foreclosed assets	2,206	1,787
Proceeds from sale of premises held for sale		3,338
Proceeds from sale of premises and equipment	62
Purchases of premises and equipment	(5,736)	(10,874)
Life insurance proceeds		649
Net cash from investing activities	(112,873)	(263,864)
Financing activities:
Net change in deposits	92,051	31,896
Net change in other borrowings	(4,335)	81,237
Repurchase of common stock	(834)	(1,629)
Dividends paid	(12,984)	(11,228)
Exercise of stock options	185	193
Net cash from financing activities	74,083	100,469
Net change in cash and cash equivalents	21,115	(117,578)
Cash and cash equivalents at beginning of year	205,428	305,612
Cash and cash equivalents at end of year	226,543	188,034
Supplemental disclosure of noncash activities:
Unrealized (loss) gain on securities available for sale	(29,704)	5,411
Loans transferred to foreclosed assets	511	726
Market value of shares tendered in-lieu of cash to pay for exercise of options and/or related taxes	1,124	3,854
Supplemental disclosure of cash flow activity:
Cash paid for interest expense	8,010	4,881
Cash paid for income taxes	11,625	$ 15,450
Assets acquired in acquisition plus goodwill recognized, net	1,456,505
Liabilities assumed in acquisition	$ 1,172,068

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 1 – Summary of Significant Accounting Policies Description of Business and Basis of Presentation TriCo Bancshares (the “Company” or “we”) is a California corporation organized to act as a bank holding company for Tri Counties Bank (the “Bank”). The Company and the Bank are headquartered in Chico, California. The Bank is a California-chartered bank that is engaged in the general commercial banking business in 29 California counties. The Bank operates from 69 traditional branches, 9 in-store The consolidated financial statements are prepared in accordance with accounting policies generally accepted in the United States of America and general practices in the banking industry. All adjustments necessary for a fair presentation of these consolidated financial statements have been included and are of a normal and recurring nature. The financial statements include the accounts of the Company. All inter-company accounts and transactions have been eliminated in consolidation. For financial reporting purposes, the Company’s investments in the Capital Trusts of $1,741,000 are accounted for under the equity method and, accordingly, are not consolidated and are included in other assets on the consolidated balance sheet. The subordinated debentures issued and guaranteed by the Company and held by the Capital Trusts are reflected as debt on the Company’s consolidated balance sheet. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires Management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the rules and regulatinos of the Securities and Exchange Commission. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidtated financial statements and notes thereto included in the Company’s Annua Report on Form 10-K Significant Group Concentration of Credit Risk The Company grants agribusiness, commercial, consumer, and residential loans to customers located throughout northern and central California. The Company has a diversified loan portfolio within the business segments located in this geographical area. The Company currently classifies all its operation into one business segment that it denotes as community banking. Geographical Descriptions For the purpose of describing the geographical location of the Company’s loans, the Company has defined northern California as that area of California north of, and including, Stockton; central California as that area of the state south of Stockton, to and including, Bakersfield; and southern California as that area of the state south of Bakersfield. Business Combinations The Company accounts for acquisitions of businesses using the acquisition method of accounting. Under the acquisition method, assets acquired and liabilities assumed are recorded at their estimated fair values at the date of acquisition. Management utilizes various valuation techniques including discounted cash flow analyses to determine these fair values. Any excess of the purchase price over amounts allocated to the acquired assets, including identifiable intangible assets, and liabilities assumed is recorded as goodwill. Cash and Cash Equivalents Net cash flows are reported for loan and deposit transactions and other borrowings. For purposes of the consolidated statement of cash flows, cash, due from banks with maturities less than 90 days, interest-earning deposits in other banks, and Federal funds sold are considered to be cash equivalents. Revenue Recognition The Company records revenue from contracts with customers in accordance with Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. Most of our revenue-generating transactions are not subject to Topic 606, including revenue generated from financial instruments, such as our loans and investment securities. In addition, certain noninterest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the new guidance. The Company’s noninterest revenue streams are largely based on transactional activity, or standard month-end month-end Accounting Standards Adopted in 2018 FASB Accounting Standards Update (ASU) No. 2014- 09, Revenue from Contracts with Customers (Topic 606): 2014-09 2014-09 2014-09 2014-09 In January 2016, the FASB issued ASU No. 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.” available-for-sale No. 2016-01 Fair Value Measurement FASB issued ASU No. 2016-18, Statement of Cash Flows - Restricted Cash (Topic 230). ASU 2016-18 beginning-of-period end-of-period ASU 2016-18 FASB issued ASU No. 2017-01, Business Combinations - Clarifying the Definition of a Business (Topic 805). ASU 2017-01 ASU 2017-01 ASU 2017-01 FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715). 2017-07 ASU 2017-07 FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718). ASU 2017-09 ASU 2017-09, ASU 2017-09 FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220). 2018-02 2018-02 2018-02 Accounting Standards Pending Adoption FASB issued ASU No. 2016-02, Leases (Topic 842) ASU 2016-2, on-balance ASU 2016-02 No. 2018-10 2018-11. No. 2016-02, 2018-10 2018-11. FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other: Simplifying the Test for Goodwill Impairment (Topic 350): 2017-04 ASU 2017-04 FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Topic 310). ASU 2017-08 non-pooled ASU 2017-08 ASU 2017-08 In August 2018, the FASB issued ASU No. 2018-13, “Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement.” No. 2018-13 No. 2018-13 In August 2018, the FASB issued ASU No. 2018-14, “Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans.” 2018-14 2018-14

Business Combinations

Business Combinations	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Business Combinations	Note 2 - Business Combinations Merger with FNB Bancorp On July 6, 2018, the Company completed the acquisition of FNB Bancorp (“FNBB”) for an aggregate transaction value of $291,132,000. FNBB was merged into the Company, and the Company issued 7,405,277 shares of common stock to the former shareholders of FNBB. FNBB’s subsidiary, First National Bank of Northern California, merged into the Bank on the same day. The Company also paid $6.7 million to settle and retire all FNBB stock options outstanding as of the acquisition date. Upon the consummation of the merger, the Company added 12 branches within San Mateo, San Francisco, and Santa Clara counties. In accordance with accounting for business combinations, the Company recorded $156,661,000 of goodwill and $27,605,000 of core deposit intangibles on the acquisition date. The core deposit intangibles will be amortized over the weighted average remaining life of 6.2 years with no significant residual value. For tax purposes, purchase prices accounting adjustments including goodwill are all non-taxable non-deductible. The acquisition was consistent with the Company’s strategy to expand into the Bay Area market. The acquisition offers the Company the opportunity to increase profitability by introducing existing products and services to the acquired customer base as well as add new customers in the expanded region. Goodwill arising from the acquisition consisted largely of the estimated cost savings resulting from the combined operations. The following table summarizes the consideration paid for FNBB and the amounts of assets acquired and liabilities assumed that were recorded at the acquisition date (in thousands). FNB Bancorp Fair value of consideration transferred: Fair value of shares issued $ 284,437 Cash consideration 6,695 Total fair value of consideration transferred 291,132 Assets acquired: Cash and cash equivalents 37,308 Securities available for sale 335,667 Restricted equity securities 7,723 Loans 834,683 Premises and equipment 30,522 Cash value of life insurance 16,817 Core deposit intangible 27,605 Other assets 16,214 Total assets acquired 1,306,539 Liabilities assumed: Deposits 991,935 Other liabilities 15,133 Short-term borrowings - Federal Home Loan Bank 165,000 Total liabilities assumed 1,172,068 Total net assets acquired 134,471 Goodwill recognized $ 156,661 The fair value of net assets acquired includes fair value adjustments to certain loans that were not considered impaired (PNCI loans) as of the acquisition date. The fair value adjustments were determined using discounted contractual cash flows. As such, these loans were not considered impaired at the acquisition date and were not subject to the guidance relating to purchased credit impaired loans (PCI loans), which have shown evidence of credit deterioration since origination. The gross contractual amounts receivable and fair value for PNCI loans as of the acquisition date was $866,189,000 and $833,381,000, respectively. The gross contractual amounts receivable and fair value for PCI loans as of the acquisition date was $1,683,000 and $1,302,000, respectively. The accompanying condensed consolidated financial statements include the accounts of FNB Bancorp since July 6, 2018. The table below presents the unaudited pro forma information as if the acquisition of FNB Bancorp had occurred on January 1, 2017 after giving effect to certain acquisition accounting adjustments. The pro forma information for the three and nine months ended September 30, 2018 and 2017 includes acquisition adjustments for the amortization/accretion on loans, core deposit intangibles, and related income tax effects. The pro forma financial information also includes one-time Three months ended Nine months ended September 30, September 30, September 30, September 30, ( in thousands, except per share data) Summarized proforma income statement data: Net interest income $ 61,259 $ 57,329 $ 178,434 $ 168,363 Provision for (benefit from) loan losses 2,651 765 1,374 (1,728 ) Noninterest income 12,288 13,902 38,517 40,537 Noninterest expense (40,850 ) (45,983 ) (135,048 ) (135,218 ) Income before taxes 30,046 24,483 80,529 75,410 Income taxes 8,384 9,055 22,996 27,436 Net income $ 21,662 $ 15,428 $ 57,533 $ 47,974 Basic earnings per share $ 0.72 $ 0.51 $ 1.76 $ 1.58 Diluted earnings per share $ 0.71 $ 0.50 $ 1.74 $ 1.56 It is impracticable to separately provide information regarding the revenue and earnings of FNB Bancorp included in the Company’s consolidated income statement from the July 6, 2018 acquisition date to September 30, 2018 because the operations of FNB Bancorp were substantially comingled with the operations of the Company as of the system conversion date of July 22, 2018.

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2018
Investments Schedule [Abstract]
Investment Securities	Note 3 - Investment Securities The amortized cost and estimated fair values of investments in debt securities are summarized in the following tables: September 30, 2018 Amortized Gross Gross Estimated Fair (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 666,021 163 (27,308 ) $ 638,876 Obligations of states and political subdivisions 129,072 107 (5,759 ) 123,420 Corporate bonds 4,368 65 (2 ) 4,431 Asset backed securities 289,550 181 (498 ) 289,233 Total debt securities available for sale $ 1,089,011 $ 516 $ (33,567 ) $ 1,055,960 Debt Securities Held to Maturity Obligations of U.S. government agencies $ 445,309 $ 88 $ (13,361 ) $ 432,036 Obligations of states and political subdivisions 14,588 58 (395 ) 14,251 Total debt securities held to maturity $ 459,897 $ 146 $ (13,756 ) $ 446,287 December 31, 2017 Amortized Gross Gross Estimated Fair (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 609,695 $ 695 $ (5,601 ) $ 604,789 Obligations of states and political subdivisions 121,597 1,888 (329 ) 123,156 Total debt securities available for sale $ 731,292 $ 2,583 $ (5,930 ) $ 727,945 Debt Securities Held to Maturity Obligations of U.S. government agencies $ 500,271 $ 5,101 $ (1,889 ) $ 503,483 Obligations of states and political subdivisions 14,573 146 (37 ) 14,682 Total debt securities held to maturity $ 514,844 $ 5,247 $ (1,926 ) $ 518,165 Proceeds from sales of available for sale debt securities of $293,279,000 and $25,757,000 were received during the three months ended September 30, 2018 and 2017, respectively. Gross realized gains during the three months ended September 30, 2018 and 2017 were $207,000 and $961,000, respectively. There were no sales of investment securities during the first six months of 2018 or 2017. Investment securities with an aggregate carrying value of $548,123,000 and $285,596,000 at September 30, 2018 and December 31, 2017, respectively, were pledged as collateral for specific borrowings, lines of credit and local agency deposits. The amortized cost and estimated fair value of debt securities at September 30, 2018 by contractual maturity are shown below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. At September 30, 2018, obligations of U.S. government corporations and agencies with a cost basis totaling $1,111,330,000 consist almost entirely of residential real estate mortgage-backed securities whose contractual maturity, or principal repayment, will follow the repayment of the underlying mortgages. For purposes of the following table, the entire outstanding balance of these mortgage-backed securities issued by U.S. government corporations and agencies is categorized based on final maturity date. At September 30, 2018, the Company estimates the average remaining life of these mortgage-backed securities issued by U.S. government corporations and agencies to be approximately 6.1 years. Average remaining life is defined as the time span after which the principal balance has been reduced by half. Debt Securities Available for Sale Held to Maturity (In thousands) Amortized Estimated Fair Amortized Estimated Fair Due in one year $ 2,435 $ 2,434 $ — $ — Due after one year through five years 12,486 12,501 1,231 1,240 Due after five years through ten years 17,764 17,740 25,955 25,210 Due after ten years 1,056,326 1,023,285 432,711 419,837 Totals $ 1,089,011 $ 1,055,960 $ 459,897 $ 446,287 Gross unrealized losses on debt securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, were as follows: Less than 12 months 12 months or more Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized September 30, 2018 (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 323,972 $ (10,839 ) $ 311,035 $ (16,469 ) $ 635,007 $ (27,308 ) Obligations of states and political subdivisions 85,668 (3,659 ) 18,323 (2,100 ) 103,991 (5,759 ) Corporate bonds 1,969 (2 ) — — 1,969 (2 ) Asset backed securities 79,943 (498 ) — — 79,943 (498 ) Total debt securities available for sale $ 491,552 $ (14,998 ) $ 329,358 $ (18,569 ) $ 820,910 $ (33,567 ) Debt Securities Held to Maturity Obligations of U.S. government agencies $ 307,432 $ (7,693 ) $ 109,312 $ (5,668 ) $ 416,744 $ (13,361 ) Obligations of states and political subdivisions 8,971 (230 ) 3,076 (165 ) 12,047 (395 ) Total debt securities held to maturity $ 316,403 $ (7,923 ) $ 112,388 $ (5,833 ) $ 428,791 $ (13,756 ) Less than 12 months 12 months or more Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized December 31, 2017 (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 284,367 $ (2,176 ) $ 166,338 $ (3,425 ) $ 450,705 $ (5,601 ) Obligations of states and political subdivisions 4,904 (35 ) 17,085 (294 ) 21,989 (329 ) Total securities available for sale $ 289,271 $ (2,211 ) $ 183,423 $ (3,719 ) $ 472,694 $ (5,930 ) Debt Securities Held to Maturity Obligations of U.S. government agencies $ 93,017 $ (567 ) $ 95,367 $ (1,322 ) $ 188,384 $ (1,889 ) Obligations of states and political subdivisions 1,488 (7 ) 2,637 (30 ) 4,125 (37 ) Total debt securities held to maturity $ 94,505 $ (574 ) $ 98,004 $ (1,352 ) $ 192,509 $ (1,926 ) Obligations of U.S. government agencies: Unrealized losses on investments in obligations of U.S. government agencies are caused by interest rate increases. The contractual cash flows of these securities are guaranteed by U.S. Government Sponsored Entities (principally Fannie Mae and Freddie Mac). It is expected that the securities would not be settled at a price less than the amortized cost of the investment. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell and more likely than not will not be required to sell, these investments are not considered other-than-temporarily impaired. At September, 2018, 171 debt securities representing obligations of U.S. government agencies had unrealized losses with aggregate depreciation of (3.7%) from the Company’s amortized cost basis. Obligations of states and political subdivisions: The unrealized losses on investments in obligations of states and political subdivisions were caused by increases in required yields by investors in these types of securities. It is expected that the securities would not be settled at a price less than the amortized cost of the investment. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell and more likely than not will not be required to sell, these investments are not considered other-than-temporarily impaired. At September 30, 2018, 132 debt securities representing obligations of states and political subdivisions had unrealized losses with aggregate depreciation of (5.0%) from the Company’s amortized cost basis. Corporate bonds: The unrealized losses on investments in corporate bonds were caused by increases in required yields by investors in these types of securities. It is expected that the securities would not be settled at a price less than the amortized cost of the investment. Because management believes the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell and more likely than not will not be required to sell, these investments are not considered other-than-temporarily impaired. At September 30, 2018, one corporate bond had unrealized losses with aggregate depreciation of (0.1%) from the Company’s amortized cost basis. Asset backed securities: The unrealized losses on investments in asset backed securities were caused by increases in required yields by investors in these types of securities. At the time of purchase, each of these securities were rated AA or AAA and through September 30, 2018 have not experienced any deterioration in credit rating. The Company continues to monitor these securities for changes in credit rating or other indications of credit deterioration. Because management believes the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell and more likely than not will not be required to sell, these investments are not considered other-than-temporarily impaired. At September 30, 2018, 6asset backed securities had unrealized losses with aggregate depreciation of (0.6%) from the Company’s amortized cost basis. Marketable equity securities: All unrealized losses recognized during the reporting period were for equity securities still held at September 30, 2018.

Loans

Loans	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans	Note 4 – Loans A summary of loan balances follows (in thousands): September 30, 2018 Originated PNCI PCI Total Mortgage loans on real estate: Residential 1-4 $ 340,515 $ 182,201 $ 1,698 $ 524,414 Commercial 1,863,604 736,299 7,885 2,607,788 Total mortgage loans on real estate 2,204,119 918,500 9,583 3,132,202 Consumer: Home equity lines of credit 284,956 44,881 1,299 331,136 Home equity loans 35,556 4,690 447 40,693 Other 26,294 23,120 42 49,456 Total consumer loans 346,806 72,691 1,788 421,285 Commercial 234,741 52,479 2,427 289,647 Construction: Residential 81,533 33,041 — 114,574 Commercial 63,508 6,220 — 69,728 Total construction 145,041 39,261 — 184,302 Total loans, net of deferred loan fees and discounts $ 2,930,707 $ 1,082,931 $ 13,798 $ 4,027,436 Total principal balance of loans owed, net of charge-offs $ 2,940,897 $ 1,120,654 $ 21,007 $ 4,082,558 Unamortized net deferred loan fees (10,190 ) — — (10,190 ) Discounts to principal balance of loans owed, net of charge-offs — (37,723 ) (7,209 ) (44,932 ) Total loans, net of unamortized deferred loan fees and discounts $ 2,930,707 $ 1,082,931 $ 13,798 $ 4,027,436 Allowance for loan losses $ (30,927 ) $ (566 ) $ (110 ) $ (31,603 ) December 31, 2017 Originated PNCI PCI Total Mortgage loans on real estate: Residential 1-4 $ 320,522 $ 63,519 $ 1,385 $ 385,426 Commercial 1,690,510 215,823 8,563 1,914,896 Total mortgage loan on real estate 2,011,032 279,342 9,948 2,300,322 Consumer: Home equity lines of credit 269,942 16,248 2,498 288,688 Home equity loans 39,848 2,698 485 43,031 Other 22,859 2,251 45 25,155 Total consumer loans 332,649 21,197 3,028 356,874 Commercial 209,437 8,391 2,584 220,412 Construction: Residential 67,920 10 — 67,930 Commercial 69,364 263 — 69,627 Total construction 137,284 273 — 137,557 Total loans, net of deferred loan fees and discounts $ 2,690,402 $ 309,203 $ 15,560 $ 3,015,165 Total principal balance of loans owed, net of charge-offs $ 2,699,053 $ 316,238 $ 23,181 $ 3,038,472 Unamortized net deferred loan fees (8,651 ) — — (8,651 ) Discounts to principal balance of loans owed, net of charge-offs — (7,035 ) (7,621 ) (14,656 ) Total loans, net of unamortized deferred loan fees and discounts $ 2,690,402 $ 309,203 $ 15,560 $ 3,015,165 Allowance for loan losses $ (29,122 ) $ (929 ) $ (272 ) $ (30,323 ) The following is a summary of the change in accretable yield for PCI loans during the periods indicated (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Change in accretable yield: Balance at beginning of period $ 3,996 $ 7,956 $ 4,262 $ 10,348 Accretion to interest income (253 ) (594 ) (769 ) (2,554 ) Reclassification (to) from nonaccretable difference (47 ) (2,893 ) 203 (3,325 ) Balance at end of period $ 3,696 $ 4,469 $ 3,696 $ 4,469

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Allowance for Loan Losses	Note 5 - Allowance for Loan Losses The following tables summarize the activity in the allowance for loan losses, and ending balance of loans, net of unearned fees for the periods indicated. Allowance for Loan Losses – Three Months Ended September 30, 2018 (in thousands) Beginning Charge-offs Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 1,991 $ (25 ) $ — $ 434 $ 2,400 Commercial 11,607 — 15 1,257 12,879 Total mortgage loans on real estate 13,598 (25 ) 15 1,691 15,279 Consumer: Home equity lines of credit 5,048 (172 ) 151 194 5,221 Home equity loans 1,532 (23 ) 139 (55 ) 1,593 Other 557 (229 ) 63 309 700 Total consumer loans 7,137 (424 ) 353 448 7,514 Commercial 6,378 (693 ) 202 337 6,224 Construction: Residential 1,434 — — 192 1,626 Commercial 977 — — (17 ) 960 Total construction 2,411 — — 175 2,586 Total $ 29,524 $ (1,142 ) $ 570 $ 2,651 $ 31,603 Allowance for Loan Losses – Nine Months Ended September 30, 2018 (in thousands) Beginning Charge-offs Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 2,317 $ (77 ) $ — $ 160 $ 2,400 Commercial 11,441 (15 ) 51 1,402 12,879 Total mortgage loans on real estate 13,758 (92 ) 51 1,562 15,279 Consumer: Home equity lines of credit 5,800 (276 ) 677 (980 ) 5,221 Home equity loans 1,841 (23 ) 176 (401 ) 1,593 Other 586 (597 ) 208 503 700 Total consumer loans 8,227 (896 ) 1,061 (878 ) 7,514 Commercial 6,512 (952 ) 331 333 6,224 Construction: Residential 1,184 — — 442 1,626 Commercial 642 — — 318 960 Total construction 1,826 — — 760 2,586 Total $ 30,323 $ (1,940 ) $ 1,443 $ 1,777 $ 31,603 Allowance for Loan Losses – As of September 30, 2018 (in thousands) Individually Loans pooled Loans acquired Total allowance Mortgage loans on real estate: Residential 1-4 $ 57 $ 2,313 $ 30 $ 2,400 Commercial 268 12,552 59 12,879 Total mortgage loans on real estate 325 14,865 89 15,279 Consumer: Home equity lines of credit 168 5,046 7 5,221 Home equity loans 175 1,418 — 1,593 Other 103 597 — 700 Total consumer loans 446 7,061 7 7,514 Commercial 1,857 4,353 14 6,224 Construction: Residential — 1,626 — 1,626 Commercial — 960 — 960 Total construction — 2,586 — 2,586 Total $ 2,628 $ 28,865 $ 110 $ 31,603 Loans, Net of Unearned fees – As of September 30, 2018 (in thousands) Individually Loans pooled Loans acquired Total loans, net Mortgage loans on real estate: Residential 1-4 $ 4,781 $ 517,935 $ 1,698 $ 524,414 Commercial 13,244 2,586,659 7,885 2,607,788 Total mortgage loans on real estate 18,025 3,104,594 9,583 3,132,202 Consumer: Home equity lines of credit 2,188 327,649 1,299 331,136 Home equity loans 2,406 37,840 447 40,693 Other 243 49,171 42 49,456 Total consumer loans 4,837 414,660 1,788 421,285 Commercial 4,632 282,588 2,427 289,647 Construction: Residential — 114,574 — 114,574 Commercial — 69,728 — 69,728 Total construction — 184,302 — 184,302 Total $ 27,494 $ 3,986,144 $ 13,798 $ 4,027,436 Allowance for Loan Losses – Year Ended December 31, 2017 (in thousands) Beginning Charge-offs Recoveries Provision Ending Mortgage loans on real estate: Residential 1-4 $ 2,748 $ (60 ) $ — $ (371 ) $ 2,317 Commercial 11,517 (186 ) 397 (287 ) 11,441 Total mortgage loans on real estate 14,265 (246 ) 397 (658 ) 13,758 Consumer: Home equity lines of credit 7,044 (98 ) 698 (1,844 ) 5,800 Home equity loans 2,644 (332 ) 242 (713 ) 1,841 Other 622 (1,186 ) 375 775 586 Total consumer loans 10,310 (1,616 ) 1,315 (1,782 ) 8,227 Commercial 5,831 (1,444 ) 428 1,697 6,512 Construction: Residential 1,417 (1,104 ) — 871 1,184 Commercial 680 — 1 (39 ) 642 Total construction 2,097 (1,104 ) 1 832 1,826 Total $ 32,503 $ (4,410 ) $ 2,141 $ 89 $ 30,323 Allowance for Loan Losses – As of December 31, 2017 (in thousands) Individually Loans pooled Loans acquired Total allowance Mortgage loans on real estate: Residential 1-4 $ 230 $ 1,932 $ 155 $ 2,317 Commercial 30 11,351 60 11,441 Total mortgage loans on real estate 260 13,283 215 13,758 Consumer: Home equity lines of credit 427 5,356 17 5,800 Home equity loans 107 1,734 — 1,841 Other 57 529 — 586 Total consumer loans 591 7,619 17 8,227 Commercial 1,848 4,624 40 6,512 Construction: Residential — 1,184 — 1,184 Commercial — 642 — 642 Total construction — 1,826 — 1,826 Total $ 2,699 $ 27,352 $ 272 $ 30,323 Loans, Net of Unearned fees – As of December 31, 2017 (in thousands) Individually Loans pooled Loans acquired Total loans, net Mortgage loans on real estate: Residential 1-4 $ 5,298 $ 378,743 $ 1,385 $ 385,426 Commercial 13,911 1,892,422 8,563 1,914,896 Total mortgage loans on real estate 19,209 2,271,165 9,948 2,300,322 Consumer: Home equity lines of credit 2,688 283,502 2,498 288,688 Home equity loans 1,470 41,076 485 43,031 Other 257 24,853 45 25,155 Total consumer loans 4,415 349,431 3,028 356,874 Commercial 4,470 213,358 2,584 220,412 Construction: Residential 140 67,790 — 67,930 Commercial — 69,627 — 69,627 Total construction 140 137,417 — 137,557 Total $ 28,234 $ 2,971,371 $ 15,560 $ 3,015,165 Allowance for Loan Losses – Three Months Ended September 30, 2017 (in thousands) Beginning Charge- Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 2,495 $ (60 ) $ — $ (217 ) $ 2,218 Commercial 10,119 (20 ) 238 1,033 11,370 Total mortgage loans on real estate 12,614 (80 ) 238 816 13,588 Consumer: Home equity lines of credit 6,156 (14 ) 189 (610 ) 5,721 Home equity loans 2,354 (94 ) 121 (390 ) 1,991 Other 645 (349 ) 91 203 590 Total consumer loans 9,155 (457 ) 401 (797 ) 8,302 Commercial 4,729 (291 ) 61 303 4,802 Construction: Residential 1,179 (33 ) — 284 1,430 Commercial 466 — — 159 625 Total construction 1,645 (33 ) — 443 2,055 Total $ 28,143 $ (861 ) $ $ 765 $ 28,747 Allowance for Loan Losses – Nine Months Ended September 30, 2017 (in thousands) Beginning Charge-offs Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 2,748 $ (60 ) $ $ (470 ) $ 2,218 Commercial 11,517 (170 ) 365 (342 ) 11,370 Total mortgage loans on real estate 14,265 (230 ) 365 (812 ) 13,588 Consumer: Home equity lines of credit 7,044 (98 ) 487 (1,712 ) 5,721 Home equity loans 2,644 (331 ) 146 (468 ) 1,991 Other 622 (831 ) 300 499 590 Total consumer loans 10,310 (1,260 ) 933 (1,681 ) 8,302 Commercial 5,831 (1,188 ) 315 (156 ) 4,802 Construction: Residential 1,417 (1,104 ) — 1,117 1,430 Commercial 680 — 1 (56 ) 625 Total construction 2,097 (1,104 ) 1 1,061 2,055 Total $ 32,503 $ (3,782 ) $ 1,614 $ (1,588 ) $ 28,747 Allowance for Loan Losses – As of September 30, 2017 (in thousands) Individually Loans pooled Loans acquired Total allowance Mortgage loans on real estate: Residential 1-4 $ 240 $ 1,978 $ — $ 2,218 Commercial 73 11,022 275 11,370 Total mortgage loans on real estate 313 13,000 275 13,588 Consumer: Home equity lines of credit 363 5,346 12 5,721 Home equity loans 111 1,880 — 1,991 Other 77 513 — 590 Total consumer loans 551 7,739 12 8,302 Commercial 1,276 3,526 — 4,802 Construction: Residential — 1,430 — 1,430 Commercial — 625 — 625 Total construction — 2,055 — 2,055 Total $ 2,140 $ 26,320 $ 287 $ 28,747 Loans, Net of Unearned fees – As of September 30, 2017 (in thousands) Individually Loans pooled Loans acquired Total Loans Mortgage loans on real estate: Residential 1-4 $ 5,027 $ 384,640 $ 1,405 $ 391,072 Commercial 19,788 1,775,843 8,171 1,803,802 Total mortgage loans on real estate 24,815 2,160,483 9,576 2,194,874 Consumer: Home equity lines of credit 2,219 284,335 2,952 289,506 Home equity loans 1,842 42,454 737 45,033 Other 267 26,470 44 26,781 Total consumer loans 4,328 353,259 3,733 361,320 Commercial 2,938 221,846 2,695 227,479 Construction: Residential 144 74,976 — 75,120 Commercial — 72,820 — 72,820 Total construction 144 147,796 — 147,940 Total $ 32,225 $ 2,883,384 $ 16,004 $ 2,931,613 As part of the on-going (iii) non-performing The Company utilizes a risk grading system to assign a risk grade to each of its loans. Loans are graded on a scale ranging from Pass to Loss. A description of the general characteristics of the risk grades is as follows: • Pass • Special Mention • Substandard • Doubtful • Loss The following tables present ending loan balances by loan category and risk grade for the periods indicated: Credit Quality Indicators Originated Loans – As of September 30, 2018 (in thousands) Pass Special Substandard Doubtful / Loss Total Originated Mortgage loans on real estate: Residential 1-4 $ 334,902 $ 1,690 $ 3,923 $ — $ 340,515 Commercial 1,821,995 28,747 12,862 — 1,863,604 Total mortgage loans on real estate 2,156,897 30,437 16,785 — 2,204,119 Consumer: Home equity lines of credit 281,480 1,747 1,729 — 284,956 Home equity loans 32,242 1,006 2,308 — 35,556 Other 25,885 334 75 — 26,294 Total consumer loans 339,607 3,087 4,112 — 346,806 Commercial 220,328 9,942 4,471 — 234,741 Construction: Residential 81,235 32 266 — 81,533 Commercial 62,660 848 — — 63,508 Total construction 143,895 880 266 — 145,041 Total loans $ 2,860,727 $ 44,346 $ 25,634 $ — $ 2,930,707 Credit Quality Indicators PNCI Loans – As of September 30, 2018 (in thousands) Pass Special Substandard Doubtful / Loss Total PNCI Mortgage loans on real estate: Residential 1-4 $ 179,634 $ 880 $ 1,687 $ — $ 182,201 Commercial 729,261 3,478 3,560 — 736,299 Total mortgage loans on real estate 908,895 4,358 5,247 — 918,500 Consumer: Home equity lines of credit 43,406 826 649 — 44,881 Home equity loans 4,471 116 103 — 4,690 Other 23,083 32 5 — 23,120 Total consumer loans 70,960 974 757 — 72,691 Commercial 51,633 734 112 — 52,479 Construction: Residential 33,041 — — — 33,041 Commercial 6,220 — — — 6,220 Total construction 39,261 — — — 39,261 Total loans $ 1,070,749 $ 6,066 $ 6,116 $ — $ 1,082,931 Credit Quality Indicators Originated Loans – As of December 31, 2017 (in thousands) Pass Special Substandard Doubtful / Loss Total Originated Mortgage loans on real estate: Residential 1-4 $ 315,120 $ 2,234 $ 3,168 $ — $ 320,522 Commercial 1,649,333 18,434 22,743 — 1,690,510 Total mortgage loans on real estate 1,964,453 20,668 25,911 — 2,011,032 Consumer: Home equity lines of credit 265,345 2,558 2,039 — 269,942 Home equity loans 37,428 800 1,620 — 39,848 Other 22,432 272 155 — 22,859 Total consumer loans 325,205 3,630 3,814 — 332,649 Commercial 195,208 9,492 4,737 — 209,437 Construction: Residential 67,813 — 107 — 67,920 Commercial 64,492 4,872 — — 69,364 Total construction 132,305 4,872 107 — 137,284 Total loans $ 2,617,171 $ 38,662 $ 34,569 $ — $ 2,690,402 Credit Quality Indicators PNCI Loans – As of December 31, 2017 (in thousands) Pass Special Substandard Doubtful / Loss Total PNCI Mortgage loans on real estate: Residential 1-4 $ 61,411 $ 218 $ 1,890 $ — $ 63,519 Commercial 203,751 11,513 559 — 215,823 Total mortgage loans on real estate 265,162 11,731 2,449 — 279,342 Consumer: Home equity lines of credit 14,866 450 932 — 16,248 Home equity loans 2,433 188 77 — 2,698 Other 2,207 38 6 — 2,251 Total consumer loans 19,506 676 1,015 — 21,197 Commercial 8,390 1 — — 8,391 Construction: Residential 10 — — — 10 Commercial 263 — — — 263 Total construction 273 — — — 273 Total $ 293,331 $ 12,408 $ 3,464 $ — $ 309,203 Consumer loans, whether unsecured or secured by real estate, automobiles, or other personal property, are susceptible to three primary risks; non-payment non-payment Problem consumer loans are generally identified by payment history and current performance of the borrower (delinquency). The Bank manages its consumer loan portfolios by monitoring delinquency and contacting borrowers to encourage repayment, suggest modifications if appropriate, and, when continued scheduled payments become unrealistic, initiate repossession or foreclosure through appropriate channels. Commercial real estate loans generally fall into two categories, owner-occupied and non-owner non-owner Construction loans, whether owner occupied or non-owner Problem commercial loans are generally identified by periodic review of financial information which may include financial statements, tax returns, rent rolls and payment history of the borrower (delinquency). Based on this information the Bank may decide to take any of several courses of action including demand for repayment, additional collateral or guarantors, and, when repayment becomes unlikely through borrower’s income and cash flow, repossession or foreclosure of the underlying collateral. Collateral values may be determined by appraisals obtained through Bank approved, licensed appraisers, qualified independent third parties, public value information (blue book values for autos), sales invoices, or other appropriate means. Appropriate valuations or revaluations are obtained at initiation of the credit and periodically, but not less than every twelve months depending on collateral type, once repayment is questionable and the loan has been classified. Once a loan becomes delinquent and repayment becomes questionable, a Bank collection officer will address collateral shortfalls with the borrower and attempt to obtain additional collateral. If this is not forthcoming and payment in full is unlikely, the Bank will estimate its probable loss, using a recent valuation as appropriate to the underlying collateral less estimated costs of sale, and charge the loan down to the estimated net realizable amount. Depending on the length of time until ultimate collection, the Bank may revalue the underlying collateral and take additional charge-offs as warranted. Revaluations may occur as often as every 3-12 The following table shows the ending balance of current and past due originated loans by loan category as of the date indicated: Analysis of Originated Past Due Loans - As of September 30, 2018 ³ (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 $ 275 $ 749 $ 738 $ 1,762 $ 338,753 $ 340,515 $ — Commercial 499 150 117 766 1,862,838 1,863,604 — Total mortgage loans on real estate 774 899 855 2,528 2,201,591 2,204,119 — Consumer: Home equity lines of credit 1,450 97 112 1,659 283,297 284,956 — Home equity loans 527 293 411 1,231 34,325 35,556 — Other 262 24 — 286 26,008 26,294 — Total consumer loans 2,239 414 523 3,176 343,630 346,806 — Commercial 1,010 134 1,309 2,453 232,288 234,741 — Construction: Residential 488 — — 488 81,045 81,533 — Commercial — — — — 63,508 63,508 — Total construction 488 — — 488 144,553 145,041 — Total originated loans $ 4,511 $ 1,447 $ 2,687 $ 8,645 $ 2,922,062 $ 2,930,707 $ — The following table shows the ending balance of current and past due PNCI loans by loan category as of the date indicated: Analysis of PNCI Past Due Loans - As of September 30, 2018 ³ (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 $ $ 397 $ 163 $ 560 $ 181,641 $ 182,201 $ — Commercial 992 18 949 1,959 734,340 736,299 949 Total mortgage loans on real estate 992 415 1,112 2,519 915,981 918,500 949 Consumer: Home equity lines of credit 613 192 227 1,032 43,849 44,881 99 Home equity loans 262 — 16 278 4,412 4,690 — Other 242 — — 242 22,878 23,120 — Total consumer loans 1,117 192 243 1,552 71,139 72,691 99 Commercial 30 472 — 502 51,977 52,479 — Construction: Residential — — — — 33,041 33,041 — Commercial — — — — 6,220 6,220 — Total construction — — — — 39,261 39,261 — Total PNCI loans $ 2,139 $ 1,079 $ 1,355 $ 4,573 $ 1,078,358 $ 1,082,931 $ 1,048 The following table shows the ending balance of current and past due originated loans by loan category as of the date indicated: Analysis of Originated Past Due Loans - As of December 31, 2017 ³ (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 $ 1,740 $ 510 $ 243 $ 2,493 $ 318,029 $ 320,522 $ — Commercial 158 987 — 1,145 1,689,365 1,690,510 — Total mortgage loans on real estate 1,898 1,497 243 3,638 2,007,394 2,011,032 — Consumer: Home equity lines of credit 528 48 372 948 268,994 269,942 — Home equity loans 511 107 373 991 38,857 39,848 — Other 56 36 3 95 22,764 22,859 — Total consumer loans 1,095 191 748 2,034 330,615 332,649 — Commercial 956 738 1,527 3,221 206,216 209,437 — Construction: Residential 34 — — 34 67,886 67,920 — Commercial — — — — 69,364 69,364 — Total construction 34 — — 34 137,250 137,284 — Total loans $ 3,983 $ 2,426 $ 2,518 $ 8,927 $ 2,681,475 $ 2,690,402 $ — The following table shows the ending balance of current and past due PNCI loans by loan category as of the date indicated: Analysis of PNCI Past Due Loans - As of December 31, 2017 > 90 Days (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 family $ 1,495 $ 90 $ 109 $ 1,694 $ 61,825 $ 63,519 $ 81 Commercial 70 — — 70 215,753 215,823 — Total mortgage loans on real estate 1,565 90 109 1,764 277,578 279,342 81 Consumer: Home equity lines of credit 298 228 330 856 15,392 16,248 200 Home equity loans 30 — — 30 2,668 2,698 — Other 6 26 — 32 2,219 2,251 — Total consumer loans 334 254 330 918 20,279 21,197 200 Commercial — — — — 8,391 8,391 — Construction: Residential — — — — 10 10 — Commercial — — — — 263 263 — Total construction — — — — 273 273 — Total loans $ 1,899 $ 344 $ 439 $ 2,682 $ 306,521 $ 309,203 $ 281 Interest income on originated nonaccrual loans that would have been recognized during the three months ended September 30, 2018 and 2017, if all such loans had been current in accordance with their original terms, totaled $338,000 and $244,000, respectively. Interest income actually recognized on these originated loans during the three months ended September 30, 2018 and 2017 was $59,000 and $33,000, respectively. Interest income on PNCI nonaccrual loans that would have been recognized during the three months ended September 30, 2018 and 2017, if all such loans had been current in accordance with their original terms, totaled $39,000 and $90,000, respectively. Interest income actually recognized on these PNCI loans during the three months ended September 30, 2018 and 2017 was $12,000 and $2,000. Interest income on originated nonaccrual loans that would have been recognized during the nine months ended September 30, 2018 and 2017, if all such loans had been current in accordance with their original terms, totaled $964,000 and $617,000, respectively. Interest income actually recognized on these originated loans during the nine months ended September 30, 2018 and 2017 was $133,000 and $49,000, respectively. Interest income on PNCI nonaccrual loans that would have been recognized during the nine months ended September 30, 2018 and 2017, if all such loans had been current in accordance with their original terms, totaled $93,000 and $188,000. Interest income actually recognized on these PNCI loans during the nine months ended September 30, 2018 and 2017 was $23,000 and $14,000. The following table shows the ending balance of nonaccrual originated and PNCI loans by loan category as of the date indicated: Non Accrual Loans As of September 30, 2018 As of December 31, 2017 (in thousands) Originated PNCI Total Originated PNCI Total Mortgage loans on real estate: Residential 1-4 family $ 2,813 $ 1,219 $ 4,032 $ 1,725 $ 1,012 $ 2,737 Commercial 7,876 305 8,181 8,144 — 8,144 Total mortgage loans on real estate 10,689 1,524 12,213 9,869 1,012 10,881 Consumer: Home equity lines of credit 725 568 1,293 811 402 1,213 Home equity loans 1,933 50 1,983 1,106 44 1,150 Other 3 5 8 7 5 12 Total consumer loans 2,661 623 3,284 1,924 451 2,375 Commercial 3,737 — 3,737 3,669 — 3,669 Construction: Residential — — — — — — Commercial — — — — — — Total construction — — — — — — Total non accrual loans $ 17,087 $ 2,147 $ 19,234 $ 15,462 $ 1,463 $ 16,925 Impaired originated loans are those where management has concluded that it is probable that the borrower will be unable to pay all amounts due in accordance with the original contractual terms of the loan agreement. The following tables show the recorded investment (financial statement balance), unpaid principal balance, average recorded investment, and interest income recognized for impaired Originated and PNCI loans, segregated by those with no related allowance recorded and those with an allowance recorded for the periods indicated. The average recorded investment and interest income recognized for the three month periods ended September 30, 2018 and 2017 has not been separately presented as the amounts are not considered significant for disclosure. Impaired Originated Loans – As of, or for the Nine Months Ended, September 30, 2018 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 4,185 $ 3,251 $ 311 $ 3,562 $ 57 $ 3,883 $ 67 Commercial 12,553 9,619 2,370 11,989 268 11,549 208 Total mortgage loans on real estate 16,738 12,870 2,681 15,551 325 15,432 275 Consumer: Home equity lines of credit 1,444 1,346 59 1,405 19 1,410 32 Home equity loans 2,554 1,960 157 2,117 30 1,753 24 Other 3 — 3 3 3 3 — Total consumer loans 4,001 3,306 219 3,525 52 3,166 56 Commercial 4,868 2,135 2,497 4,632 1,857 4,626 78 Construction: Residential — — — — — 68 — Commercial — — — — — — — Total construction — — — — — 68 — Total $ 25,607 $ 18,311 $ 5,397 $ 23,708 $ 2,234 $ 23,292 $ 409 Impaired PNCI Loans – As of, or for the Nine Months Ended, September 30, 2018 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 1,302 $ 1,219 $ — $ 1,219 $ — $ 1,275 $ — Commercial 1,255 1,255 — 1,255 — 627 58 Total mortgage loans on real estate 2,557 2,474 — 2,474 — 1,902 58 Consumer: Home equity lines of credit 852 625 158 783 149 909 13 Home equity loans 296 50 239 289 145 287 9 Other 240 — 240 240 100 257 7 Total consumer loans 1,388 675 637 1,312 394 1,453 29 Commercial — — — — — — — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total $ 3,945 $ 3,149 $ 637 $ 3,786 $ 394 $ 3,355 $ 87 Impaired Originated Loans – As of, or for the Twelve Months Ended, December 31, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 4,023 $ 2,058 $ 1,881 $ 3,939 $ 230 $ 3,501 $ 143 Commercial 14,186 13,101 810 13,911 30 13,851 645 Total mortgage loans on real estate 18,209 15,159 2,691 17,850 260 17,352 788 Consumer: Home equity lines of credit 1,581 1,093 401 1,494 111 1,702 47 Home equity loans 1,627 1,107 198 1,305 10 1,193 24 Other 52 4 3 7 3 20 — Total consumer loans 3,260 2,204 602 2,806 124 2,915 71 Commercial 4,566 575 3,895 4,470 1,848 4,283 184 Construction: Residential 140 140 — 140 — 76 9 Commercial — — — — — — — Total construction 140 140 — 140 — 76 9 Total $ 26,175 $ 18,078 $ 7,188 $ 25,266 $ 2,232 $ 24,626 $ 1,052 Impaired PNCI Loans – As of, or for the Twelve Months Ended, December 31, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 1,404 $ 1,359 $ — $ 1,359 $ — $ 1,041 $ 24 Commercial — — — — — 979 — Total mortgage loans on real estate 1,404 1,359 — 1,359 — 2,020 24 Consumer: Home equity lines of credit 1,216 591 603 1,194 316 1,240 48 Home equity loans 178 44 121 165 97 117 6 Other 250 — 250 250 54 186 11 Total consumer loans 1,644 635 974 1,609 467 1,543 65 Commercial — — — — — — — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total $ 3,048 $ 1,994 $ 974 $ 2,968 $ 467 $ 3,563 $ 89 Impaired Originated Loans – As of, or for the Nine Months Ended, September 30, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 3,489 $ 1,777 $ 1,644 $ 3,421 $ 167 $ 3,242 $ 90 Commercial 18,643 17,039 1,150 18,189 73 15,990 514 Total mortgage loans on real estate 22,132 18,816 2,794 21,610 240 19,232 604 Consumer: Home equity lines of credit 1,324 1,108 110 1,218 33 1,564 25 Home equity loans 2,091 1,470 199 1,669 13 1,376 32 Other 59 3 11 14 7 23 (25 ) Total consumer loans 3,474 2,581 320 2,901 53 2,963 32 Commercial 3,262 884 2,048 2,932 1,270 3,514 69 Construction: Residential 144 144 — 144 — 78 7 Commercial — — — — — — — Total construction 144 144 — 144 — 78 7 Total $ 29,012 $ 22,425 $ 5,162 $ 27,587 $ 1,563 $ 25,787 $ 712 Impaired PNCI Loans – As of, or for the Nine Months Ended, September 30, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 1,634 $ 1,356 $ 250 $ 1,606 $ 73 $ 1,165 $ 24 Commercial 1,869 1,599 — 1,599 — 1,778 — Total mortgage loans on real estate 3,503 2,955 250 3,205 73 2,943 24 Consumer: Home equity lines of credit 1,020 394 607 1,001 328 1,143 28 Home equity loans 185 50 123 173 99 121 5 Other 253 — 253 253 71 187 8 Total consumer loans 1,458 444 983 1,427 498 1,451 41 Commercial 6 — — — 6 3 — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total $ 4,967 $ 3,399 $ 1,233 $ 4,632 $ 577 $ 4,397 $ 65 At September 30, 2018, $8,845,000 of originated loans were Troubled Debt Restructurings (TDRs) and classified as impaired. The Company had no obligations to lend additional funds on these TDRs as of September 30, 2018. At September 30, 2018, $840,000 of PNCI loans were TDRs and classified as impaired. The Company had no obligations to lend additional funds on these TDRs as of September 30, 2018. At December 31, 2017, $12,517,000 of originated loans were TDRs and classified as impaired. The Company had obligations to lend $1,000 of additional funds on these TDRs as of December 31, 2017. At December 31, 2017, $1,352,000 of PNCI loans were TDRs and classified as impaired. The Company had no obligations to lend additional funds on these TDRs as of December 31, 2017. At September 30, 2017, $13,352,000 of originated loans were TDRs and classified as impaired. The Company had obligations to lend $209,000 of additional funds on these TDRs as of September 30, 2017. At September 30, 2017, $1,611,000 of PNCI loans were TDRs and classified as impaired. The Company had obligations to lend $3,000 of additional funds on these TDRs as of September 30, 2017. The following tables show certain information regarding TDRs that occurred during the periods indicated: TDR Information for the Three Months Ended September 30, 2018 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 — $ — $ — $ — — $ — $ — Commercial 4 1,326 1,324 (308 ) — — — Total mortgage loans on real estate 4 1,326 1,324 (308 ) — — — Consumer: Home equity lines of credit — — — — 1 128 — Home equity loans 1 478 478 — — — — Other — — — — — — — Total consumer loans 1 478 478 — 1 128 — Commercial 2 203 203 — — — — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total 7 $ 2,007 $ 2,005 $ (308 ) 1 $ 128 $ — TDR Information for the Nine Months Ended September 30, 2018 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 — $ — $ — $ — — $ — $ — Commercial 6 1,743 1,741 (262 ) 1 169 — Total mortgage loans on real estate 6 1,743 1,741 (262 ) 1 169 — Consumer: Home equity lines of credit 1 133 138 — 1 128 — Home equity loans 2 599 599 — — — — Other — — — — — — — Total consumer loans 3 732 737 — 1 128 — Commercial 4 619 623 (3 ) 4 340 (2 ) Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total 13 $ 3,094 $ 3,101 $ (265 ) 6 $ 637 $ (2 ) The following tables show certain information regarding TDRs that occurred during the periods indicated: TDR Information for the Three Months Ended September 30, 2017 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 1 $ 939 $ 939 $ 169 1 $ 99 $ — Commercial 4 2,886 2,886 14 1 219 — Total mortgage loans on real estate 5 3,825 3,825 183 2 318 — Consumer: Home equity lines of credit — — — — — — — Home equity loans 1 252 252 — — — — Other — — — — — — — Total consumer loans 1 252 252 — — — — Commercial 8 1,109 1,109 28 — Construction: Residential 1 144 144 — — — — Commercial — — — — — — — Total construction 1 144 144 — — — — Total 15 $ 5,330 $ 5,330 $ 211 2 $ 318 $ — TDR Information for the Nine Months Ended September 30, 2017 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 1 $ 939 $ 939 $ 169 2 $ 223 $ — Commercial 7 3,509 3,482 (111 ) 1 219 — Total mortgage loans on real estate 8 4,448 4,421 58 3 442 — Consumer: Home equity lines of credit 3 187 187 27 — — — Home equity loans 1 252 252 — — — — Other 1 14 14 11 — — — Total consumer loans 5 453 453 38 — — — Commercial 11 1,854 1,748 37 — Construction: Residential 1 144 144 — — — — Commercial — — — — — — — Total construction 1 144 144 — — — — Total 25 $ 6,899 $ 6,766 $ 133 3 $ 442 $ — Modifications classified as TDRs can include one or a combination of the following: rate modifications, term extensions, interest only modifications, either temporary or long-term, payment modifications, and collateral substitutions/additions. For all new TDRs, an impairment analysis is conducted. If the loan is determined to be collateral dependent, any additional amount of impairment will be calculated based on the difference between estimated collectible value and the current carrying balance of the loan. This difference could result in an increased provision and is typically charged off. If the asset is determined not to be collateral dependent, the impairment is measured on the net present value difference between the expected cash flows of the restructured loan and the cash flows which would have been received under the original terms. The effect of this could result in a requirement for additional provision to the reserve. The effect of these required provisions for the period are indicated above. Typically if a TDR defaults during the period, the loan is then considered collateral dependent and, if it was not already considered collateral dependent, an appropriate provision will be reserved or charge will be taken. The additional provisions required resulting from default of previously modified TDR’s are noted above.

Foreclosed Assets

Foreclosed Assets	9 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Foreclosed Assets	Note 6 – Foreclosed Assets A summary of the activity in the balance of foreclosed assets follows (in thousands): Nine months ended September 30, 2018 2017 Beginning balance, net $ 3,226 $ 3,986 Additions/transfers from loans 536 726 Dispositions/sales (1,841 ) (1,479 ) Valuation adjustments (89 ) (162 ) Ending balance, net $ 1,832 $ 3,071 Ending valuation allowance $ (143 ) $ (248 ) Ending number of foreclosed assets 11 11 Proceeds from sale of foreclosed assets $ 2,206 $ 1,787 Gain on sale of foreclosed assets $ 390 $ 308 As of September 30, 2018, $1,269,000 of foreclosed residential real estate properties, all of which the Company has obtained physical possession of, are included in foreclosed assets. At September 30, 2018, the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are underway is $477,000.

Premises and Equipment

Premises and Equipment	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Premises and Equipment	Note 7 - Premises and Equipment Premises and equipment were comprised of: September 30, December 31, 2018 2017 (In thousands) Land & land improvements $ 28,958 $ 9,959 Buildings 64,178 50,340 Furniture and equipment 44,271 35,939 137,407 96,238 Less: Accumulated depreciation (49,073 ) (40,644 ) 88,334 55,594 Construction in progress 956 2,148 Total premises and equipment $ 89,290 $ 57,742 Depreciation expense for premises and equipment amounted to $1,685,000 and $1,520,000 for the three months ended September 30, 2018 and 2017, respectively, and $4,442,000 and $4,224,000 for the nine months ended September 30, 2018 and 2017, respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Note 8 - Goodwill and Other Intangible Assets The following table summarizes the Company’s goodwill intangible as of the dates indicated: September 30, December 31, (in thousands) 2018 Additions Reductions 2017 Goodwill $ 220,972 156,661 — $ 64,311 The following table summarizes the Company’s core deposit intangibles (CDI) as of the dates indicated: September 30, Reductions/ December 31, (in thousands) 2018 Additions Amortization 2017 Core deposit intangibles $ 37,163 27,605 — $ 9,558 Accumulated amortization (6,452 ) — $ (2,068 ) (4,384 ) Core deposit intangibles, net $ 30,711 27,605 $ (2,068 ) $ 5,174 The Company recorded additions to its CDI of $27,605,000 in conjunction with the acquisition of FNB Bancorp as of July 6, 2018. The following table summarizes the Company’s remaining estimated core deposit intangible amortization at September 30, 2018 (in thousands): Estimated Core Deposit Years Ended Intangible Amortization 2018 $ 1,431 2019 5,723 2020 5,723 2021 5,465 2022 4,776 Thereafter 7,593

Other Assets

Other Assets	9 Months Ended
	Sep. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Note 9 – Other Assets Other assets were comprised of (in thousands): September 30, December 31, Deferred tax asset, net $ 31,963 $ 21,697 Investment in low income housing tax credit funds 23,572 16,854 Prepaid expense 3,420 4,111 Tax refund receivable 2,836 4,754 Capital trusts 1,712 1,706 Software 762 1,126 Life insurance proceeds receivable — 2,242 Miscellaneous other assets 6,332 2,561 Total other assets $ 70,597 $ 55,051

Deposits

Deposits	9 Months Ended
	Sep. 30, 2018
Banking and Thrift [Abstract]
Deposits	Note 10 - Deposits A summary of the balances of deposits follows (in thousands): September 30, December 31, Noninterest-bearing demand $ 1,710,505 $ 1,368,218 Interest-bearing demand 1,152,705 971,459 Savings 1,801,087 1,364,518 Time certificates, over $250,000 140,805 73,596 Other time certificates 288,015 231,340 Total deposits $ 5,093,117 $ 4,009,131 Certificate of deposit balances of $69,000,000 and $50,000,000 from the State of California were included in time certificates, over $250,000, at September 30, 2018 and December 31, 2017, respectively. The Bank participates in a deposit program offered by the State of California whereby the State may make deposits at the Bank’s request subject to collateral and credit worthiness constraints. The negotiated rates on these State deposits are generally more favorable than other wholesale funding sources available to the Bank. Overdrawn deposit balances of $1,375,000 and $1,366,000 were classified as consumer loans at September 30, 2018 and December 31, 2017, respectively.

Other Liabilities

Other Liabilities	9 Months Ended
	Sep. 30, 2018
Other Liabilities Disclosure [Abstract]
Other Liabilities	Note 11 – Other Liabilities Other liabilities were comprised of (in thousands): September 30, December 31, Pension liability $ 37,789 $ 28,472 Low income housing tax credit fund commitments 9,146 8,554 Deferred compensation 9,450 6,605 Accrued salaries and benefits expense 8,990 6,619 Joint beneficiary agreements 3,558 3,365 Loan escrow and servicing payable 2,821 1,958 Deferred revenue 1,978 1,228 Litigation contingency — 1,450 Miscellaneous other liabilities 8,345 8,171 Total other liabilities $ 82,077 $ 66,422

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 12 - Commitments and Contingencies At September 30, 2018, future minimum commitments under non-cancelable Operating Leases (in thousands) 2018 $ 1,179 2019 4,478 2020 3,774 2021 3,372 2022 2,549 Thereafter 4,097 Future minimum lease payments $ 19,449 The following table presents a summary of the Bank’s commitments and contingent liabilities: (in thousands) September 30, December 31, Financial instruments whose amounts represent risk: Commitments to extend credit: Commercial loans $ 310,844 $ 257,220 Consumer loans 481,837 422,958 Real estate mortgage loans 149,003 66,267 Real estate construction loans 283,858 187,097 Standby letters of credit 11,277 13,075 Deposit account overdraft privilege 107,956 98,260

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2018
Federal Home Loan Banks [Abstract]
Shareholders' Equity	Note 13 – Shareholders’ Equity Dividends Paid The Bank paid to the Company cash dividends in the aggregate amounts of $13,507,000 and $5,185,000 during the three months ended September 30, 2018 and 2017, respectively, and $22,649,000 and $14,394,000 during the nine months ended September 30, 2018 and 2017, respectively. The Bank is regulated by the Federal Deposit Insurance Corporation (FDIC) and the State of California Department of Business Oversight (DBO). Absent approval from the Commissioner of the DBO, California banking laws generally limit the Bank’s ability to pay dividends to the lesser of (1) retained earnings or (2) net income for the last three fiscal years, less cash distributions paid during such period. Under this law, at December 31, 2017, the Bank could have paid dividends of $85,254,000 to the Company without the approval of the Commissioner of the DBO. Stock Repurchase Plan On August 21, 2007, the Board of Directors adopted a plan to repurchase, as conditions warrant, up to 500,000 shares of the Company’s common stock on the open market. The timing of purchases and the exact number of shares to be purchased will depend on market conditions. The 500,000 shares authorized for repurchase under this stock repurchase plan represented approximately 3.2% of the Company’s 15,814,662 outstanding common shares as of August 21, 2007. This stock repurchase plan has no expiration date. As of September 30, 2018, the Company had repurchased 166,600 shares under this plan. Stock Repurchased Under Equity Compensation Plans During the three months ended September 30, 2018 and 2017, employees tendered 11,630 and 21,738 shares, respectively, of the Company’s common stock with market value of $453,000, and $762,000, respectively, in lieu of cash to exercise options to purchase shares of the Company’s stock and to pay income taxes related to equity compensation plan instruments as permitted by the Company’s shareholder-approved equity compensation plans. The tendered shares were retired. The market value of tendered shares is the last market trade price at closing on the day an option is exercised. Stock repurchased under equity incentive plans are not included in the total of stock repurchased under the stock repurchase plan announced on August 21, 2007. During the nine months ended September 30, 2018 and 2017 employees tendered 28,850 and 107,390 shares, respectively, of the Company’s common stock with market value of $1,124,000 and $3,854,000, respectively, in lieu of cash to exercise options to purchase shares of the Company’s stock and to satisfy tax withholding requirements related to such exercises and the release of restricted stock units (RSUs) as permitted by the Company’s shareholder-approved equity compensation plans. The tendered shares were retired. The market value of tendered shares is the last market trade price at closing on the day an option is exercised. Stock repurchased under equity incentive plans are not included in the total of stock repurchased under the stock repurchase plan announced on August 21, 2007.

Stock Options and Other Equity-

Stock Options and Other Equity-Based Incentive Instruments	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Options and Other Equity-Based Incentive Instruments	Note 14 - Stock Options and Other Equity-Based Incentive Instruments Stock option activity during the nine months ended September 30, 2018 is summarized in the following table: Number Option Price Weighted Outstanding at December 31, 2017 446,400 $ 12.63 to $23.21 $ 16.84 Options granted — — to — — Options exercised (27,400 ) $ 15.34 to $23.21 $ 17.33 Options forfeited (3,000 ) $ 23.21 to $23.21 $ 23.21 Outstanding at September 30, 2018 416,000 $ 12.63 to $23.21 $ 16.77 The following table shows the number, weighted-average exercise price, intrinsic value, and weighted average remaining contractual life of options exercisable, options not yet exercisable and total options outstanding as of September 30, 2018: Currently Currently Not Total Number of options 413,000 3,000 416,000 Weighted average exercise price $ 16.72 $ 23.21 $ 16.77 Intrinsic value (in thousands) $ 9,045 $ 46 $ 9,091 Weighted average remaining contractual term (yrs.) 3.2 6.0 3.2 The 3,000 options that are currently not exercisable as of September 30, 2018 are expected to vest, on a weighted-average basis, over the next year. The Company did not modify any option grants during 2017 or the nine months ended September 30, 2018. Restricted stock unit (RSU) activity is summarized in the following table for the dates indicated: Service Condition Vesting RSUs Market Plus Service Number Weighted Number Weighted Outstanding at December 31, 2017 68,457 52,829 RSUs granted 38,605 $ 39.08 16,939 $ 36.40 Additional market plus service condition RSUs vested — 8,506 RSUs added through dividend credits 806 — RSUs released through vesting (32,516 ) (25,512 ) RSUs forfeited/expired (4,744 ) (5,478 ) Outstanding at September 30, 2018 70,608 47,284 The 70,608 of service condition vesting RSUs outstanding as of September 30, 2018 include a feature whereby each RSU outstanding is credited with a dividend amount equal to any common stock cash dividend declared and paid, and the credited amount is divided by the closing price of the Company’s stock on the dividend payable date to arrive at an additional amount of RSUs outstanding under the original grant. The 70,608 of service condition vesting RSUs outstanding as of September 30, 2018 are expected to vest, and be released, on a weighted-average basis, over the next 1.6 years. The Company expects to recognize $2,063,000 of pre-tax The 47,284 of market plus service condition vesting RSUs outstanding as of September 30, 2018 are expected to vest, and be released, on a weighted-average basis, over the next 1.7 years. The Company expects to recognize $902,000 of pre-tax

Noninterest Income and Expense

Noninterest Income and Expense	9 Months Ended
	Sep. 30, 2018
Other Income and Expenses [Abstract]
Noninterest Income and Expense	Note 15 - Noninterest Income and Expense The following table summarizes the Company’s noninterest income for the periods indicated (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 ATM and interchange fees $ 4,590 $ 4,209 $ 13,335 $ 12,472 Service charges on deposit accounts 4,015 4,160 11,407 12,102 Other service fees 676 917 2,020 2,521 Mortgage banking service fees 499 514 1,527 1,561 Change in value of mortgage servicing rights (37 ) (325 ) 38 (795 ) Total service charges and fees 9,743 9,475 28,327 27,861 Commissions on sale of non-deposit 728 672 2,414 1,984 Increase in cash value of life insurance 732 732 1,996 2,043 Gain on sale of loans 539 606 1,831 2,293 Lease brokerage income 186 234 514 601 Gain on sale of foreclosed assets 2 37 390 308 Sale of customer checks 88 89 327 287 Gain on sale of investment securities 207 961 207 961 Loss on disposal of fixed assets (152 ) (33 ) (206 ) (61 ) Loss on marketable equity securities (22 ) — (92 ) — Other 135 157 942 1,266 Total other noninterest income 2,443 3,455 8,323 9,682 Total noninterest income $ 12,186 $ 12,930 $ 36,650 $ 37,543 The components of noninterest expense were as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Base salaries, net of deferred loan origination costs $ 17,051 $ 13,600 $ 45,442 $ 40,647 Incentive compensation 3,223 2,609 7,834 6,980 Benefits and other compensation costs 5,549 4,724 15,652 14,693 Total salaries and benefits expense 25,823 20,933 68,928 62,320 Occupancy 3,173 2,799 8,574 8,196 Data processing and software 2,786 2,495 7,979 7,332 Merger and acquisition expense 4,150 — 5,227 — Equipment 1,750 1,816 4,938 5,344 ATM and POS network charges 1,195 1,425 3,858 3,353 Advertising 1,341 1,039 3,214 3,173 Professional fees 929 901 2,475 2,357 Telecommunications 819 716 2,201 2,027 Regulatory assessments and insurance 537 427 1,384 1,252 Intangible amortization 1,390 339 2,068 1,050 Postage 275 325 934 1,058 Courier service 278 235 769 752 Operational losses 217 301 763 1,166 Foreclosed assets expense 93 41 297 117 Provision for (reversal of) foreclosed asset losses (1 ) 134 89 162 Other miscellaneous expense 2,623 3,296 9,712 9,289 Total other noninterest expense 21,555 16,289 54,482 46,628 Total noninterest expense $ 47,378 $ 37,222 $ 123,410 $ 108,948

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Note 16 – Earnings Per Share Basic earnings per share represent income available to common shareholders divided by the weighted-average number of common shares outstanding during the period. Diluted earnings per share reflect additional common shares that would have been outstanding if dilutive potential common shares had been issued, as well as any adjustments to income that would result from assumed issuance. Potential common shares that may be issued by the Company relate solely from outstanding stock options, and are determined using the treasury stock method. Earnings per share have been computed based on the following: Three months ended September 30, Nine months ended September 30, (in thousands) 2018 2017 2018 2017 Net income $ 16,170 $ 11,897 $ 45,109 $ 37,565 Average number of common shares outstanding 30,011 22,932 25,317 22,901 Effect of dilutive stock options and restricted stock 280 312 300 338 Average number of common shares outstanding used to calculate diluted earnings per share 30,291 23,244 25,617 23,239 Options excluded from diluted earnings per share because the effect of these options was antidilutive 10,000 — 10,000 —

Comprehensive Income

Comprehensive Income	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Comprehensive Income	Note 17 – Comprehensive Income Accounting principles generally require that recognized revenue, expenses, gains and losses be included in net income. Although certain changes in assets and liabilities, such as unrealized gains and losses on available-for-sale The components of accumulated other comprehensive loss, included in shareholders’ equity, are as follows: September 30, December 31, (in thousands) 2018 2017 Net unrealized loss on available for sale securities $ (33,051 ) (3,409 ) Tax effect 9,771 1,433 Unrealized holding loss on available for sale securities, net of tax (23,280 ) (1,976 ) Unfunded status of the supplemental retirement plans (5,010 ) (5,352 ) Tax effect 1,481 2,250 Unfunded status of the supplemental retirement plans, net of tax (3,529 ) (3,102 ) Joint beneficiary agreement liability (150 ) (150 ) Tax effect — — Joint beneficiary agreement liability, net of tax (150 ) (150 ) Accumulated other comprehensive loss $ (26,959 ) $ (5,228 ) The components of other comprehensive income (loss) and related tax effects are as follows: Three months ended September 30, Nine months ended September 30, (in thousands) 2018 2017 2018 2017 Unrealized holding gains (losses) on available for sale securities before reclassifications $ (8,193 ) $ 674 $ (29,134 ) $ 6,372 Amounts reclassified out of accumulated other comprehensive income: Realized gains on debt securities (207 ) (961 ) (207 ) (961 ) Adoption ASU 2016-01 — — 62 — Adoption ASU 2018-02 — — (425 ) — Total amounts reclassified out of accumulated other comprehensive income (207 ) (961 ) (570 ) (961 ) Unrealized holding gains (losses) on available for sale securities after reclassifications (8,400 ) (287 ) (29,704 ) 5,411 Tax effect 2,483 121 8,763 (2,274 ) Unrealized holding gains (losses) on available for sale securities, net of tax (5,917 ) (166 ) (20,941 ) 3,137 Change in unfunded status of the supplemental retirement — — 668 — Amounts reclassified out of accumulated other comprehensive income: Amortization of prior service cost (13 ) (1 ) (40 ) (5 ) Amortization of actuarial losses 128 96 382 288 Adoption ASU 2018-02 — — (668 ) — Total amounts reclassified out of accumulated other comprehensive income 115 95 (326 ) 283 Change in unfunded status of the supplemental retirement plans after reclassifications 115 95 342 283 Tax effect (34 ) (40 ) (101 ) (119 ) Change in unfunded status of the supplemental retirement plans, net of tax 81 55 241 164 Total other comprehensive income (loss) $ (5,836 ) $ (111 ) $ (20,700 ) $ 3,301

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 18 - Fair Value Measurement The Company utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. In estimating fair value, the Company utilizes valuation techniques that are consistent with the market approach, income approach, and/or the cost approach. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability including assumptions about the risk inherent in a particular valuation technique, the effect of a restriction on the sale or use of an asset and the risk of nonperformance. Securities available-for-sale The Company groups assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the observable nature of the assumptions used to determine fair value. These levels are: Level 1 - Valuation is based upon quoted prices for identical instruments traded in active markets. Level 2 - Valuation is based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market. Level 3 - Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques. Marketable equity securities and debt securities available for sale over-the-counter Loans held for sale Impaired originated and PNCI loans Foreclosed assets Mortgage servicing rights The table below presents the recorded amount of assets and liabilities measured at fair value on a recurring basis (in thousands): Total Level 1 Level 2 Level 3 Fair value at September 30, 2018 Marketable equity securities $ 2,846 $ 2,846 $ — $ — Debt securities available for sale: Obligations of U.S. government agencies 638,876 — 638,876 — Obligations of states and political subdivisions 123,420 — 123,420 — Corporate bonds 4,431 — 4,431 — Asset backed securities 289,233 — 289,233 — Loans held for sale 3,824 — 3,824 — Mortgage servicing rights 7,122 — — 7,122 Total assets measured at fair value $ 1,069,752 $ 2,846 $ 1,059,784 $ 7,122 Total Level 1 Level 2 Level 3 Fair value at December 31, 2017 Marketable equity securities $ 2,938 $ 2,938 $ — $ — Debt securities available for sale: Obligations of U.S. government agencies 604,789 — 604,789 — Obligations of states and political subdivisions 123,156 — 123,156 — Loans held for sale 4,616 — 4,616 — Mortgage servicing rights 6,687 — — 6,687 Total assets measured at fair value $ 742,186 $ 2,938 $ 732,561 $ 6,687 Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally corresponds with the Company’s quarterly valuation process. There were no transfers between any levels during the nine months ended September 30, 2018 or the year ended December 31, 2017. The following table provides a reconciliation of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the time periods indicated. Had there been any transfer into or out of Level 3 during the time periods indicated, the amount included in the “Transfers into (out of) Level 3” column would represent the beginning balance of an item in the period (interim quarter) during which it was transferred (in thousands): Beginning Transfers Change Issuances Ending Three months ended September 30, 2018: Mortgage servicing rights $ 7,021 — $ (37 ) $ 138 $ 7,122 2017: Mortgage servicing rights $ 6,596 — $ (325 ) $ 148 $ 6,419 Beginning Transfers Change Issuances Ending Nine months ended September 30, 2018: Mortgage servicing rights $ 6,687 — $ 38 $ 397 $ 7,122 2017: Mortgage servicing rights $ 6,595 — $ (795 ) $ 619 $ 6,419 The key unobservable inputs used in determining the fair value of mortgage servicing rights are mortgage prepayment speeds and the discount rate used to discount cash projected cash flows. Generally, any significant increases in the mortgage prepayment speed and discount rate utilized in the fair value measurement of the mortgage servicing rights will result in a negative fair value adjustments (and decrease in the fair value measurement). Conversely, a decrease in the mortgage prepayment speed and discount rate will result in a positive fair value adjustment (and increase in the fair value measurement). The following table presents quantitative information about recurring Level 3 fair value measurements at September 30, 2018: Fair Value Valuation Unobservable Range, (in thousands) Technique Inputs Average Mortgage Servicing Rights $ 7,122 Discounted Constant 4.8%-33%, 7.3% Discount rate 12%, 12% The following table presents quantitative information about recurring Level 3 fair value measurements at December 31, 2017: Fair Value Valuation Unobservable Range, (in thousands) Technique Inputs Average Mortgage Servicing Rights $ 6,687 Discounted Constant 6.2%-22.0%, 8.9% Discount rate 13.0%-15.0%, 13.0% The tables below present the recorded investment in assets and liabilities measured at fair value on a nonrecurring basis, as of the dates indicated (in thousands): Total Level 1 Level 2 Level 3 Total Gains Nine months ended September 30, 2018 Fair value: Impaired Originated & PNCI loans $ 445 — — $ 445 $ (808 ) Foreclosed assets 863 — — 863 (23 ) Total assets measured at fair value $ 1,308 — — $ 1,308 $ (831 ) Total Level 1 Level 2 Level 3 Total Gains Year ended December 31, 2017 Fair value: Impaired Originated & PNCI loans $ 2,767 — — $ 2,767 $ (1,452 ) Foreclosed assets 2,217 — — 2,217 (135 ) Total assets measured at fair value $ 4,984 — — $ 4,984 $ (1,587 ) Total Level 1 Level 2 Level 3 Total Gains Nine months ended September 30, 2017 Fair value: Impaired Originated & PNCI loans $ 1,026 — — $ 1,026 $ (892 ) Foreclosed assets 2,062 — — 2,062 (157 ) Total assets measured at fair value $ 3,088 — — $ 3,088 $ (1,049 ) The impaired originated and PNCI loan amount above represents impaired, collateral dependent loans that have been adjusted to fair value. When we identify a collateral dependent loan as impaired, we measure the impairment using the current fair value of the collateral, less selling costs. Depending on the characteristics of a loan, the fair value of collateral is generally estimated by obtaining external appraisals. If we determine that the value of the impaired loan is less than the recorded investment in the loan, we recognize this impairment and adjust the carrying value of the loan to fair value through the allowance for loan and lease losses. The loss represents charge-offs or impairments on collateral dependent loans for fair value adjustments based on the fair value of collateral. The carrying value of loans fully charged-off non-covered The Company’s property appraisals are primarily based on the sales comparison approach and income approach methodologies, which consider recent sales of comparable properties, including their income generating characteristics, and then make adjustments to reflect the general assumptions that a market participant would make when analyzing the property for purchase. These adjustments may increase or decrease an appraised value and can vary significantly depending on the location, physical characteristics and income producing potential of each property. Additionally, the quality and volume of market information available at the time of the appraisal can vary from period to period and cause significant changes to the nature and magnitude of comparable sale adjustments. Given these variations, comparable sale adjustments are generally not a reliable indicator for how fair value will increase or decrease from period to period. Under certain circumstances, management discounts are applied based on specific characteristics of an individual property. The following table presents quantitative information about Level 3 fair value measurements for financial instruments measured at fair value on a nonrecurring basis at September 30, 2018: Fair Value Valuation Range, (in thousands) Technique Unobservable Inputs Weighted Average September 30, 2018 Impaired Originated & PNCI loans $ 445 Sales comparison Adjustment for differences (55.8%) - 60%; (28%) Income approach Capitalization rate N/A Foreclosed assets (Residential real estate) $ 744 Sales comparison Adjustment for differences (47%) - 52%; 0.9% Foreclosed assets (Commercial real estate) $ 92 Sales comparison Adjustment for differences (65%) - 20%; (45%) Foreclosed assets (Land and construction) $ 27 Sales comparison Adjustment for differences Information not meaningful The following table presents quantitative information about Level 3 fair value measurements for financial instruments measured at fair value on a nonrecurring basis at December 31, 2017: Fair Value Valuation Range, (in thousands) Technique Unobservable Inputs Weighted Average December 31, 2017 Impaired Originated & PNCI loans $ 2,767 Sales comparison Adjustment for differences (74%) - 23%; (19.76%) Income approach Capitalization rate N/A Foreclosed assets (Land & construction) $ 1,341 Sales comparison Adjustment for differences (53%) - 283%; 167% Foreclosed assets (Residential real estate) $ 622 Sales comparison Adjustment for differences (47%) - 39%; (3.13%) Foreclosed assets (Commercial real estate) $ 254 Sales comparison Adjustment for differences (84%) - 19%; (84%) In addition to the methods and assumptions used to estimate the fair value of each class of financial instrument noted above, the following methods and assumptions were used to estimate the fair value of other classes of financial instruments for which it is practical to estimate the fair value. Short-term Instruments Securities held to maturity over-the-counter Restricted Equity Securities Originated and PNCI loans PCI Loans Deposit Liabilities Other Borrowings Junior Subordinated Debentures Commitments to Extend Credit and Standby Letters of Credit Fair values for financial instruments are management’s estimates of the values at which the instruments could be exchanged in a transaction between willing parties. These estimates are subjective and may vary significantly from amounts that would be realized in actual transactions. In addition, other significant assets are not considered financial assets including, any mortgage banking operations, deferred tax assets, and premises and equipment. Further, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on the fair value estimates and have not been considered in any of these estimates. In January 2018, the Company adopted the provisions of Accounting Standard Update 2016-01 Recognition and Measurement of Financial Assets and Financial Liabilities September 30, 2018 December 31, 2017 Carrying Fair Carrying Fair Amount Value Amount Value Financial assets: Level 1 inputs: Cash and due from banks $ 109,363 $ 109,363 $ 105,968 $ 105,968 Cash at Federal Reserve and other banks 117,180 117,180 99,460 99,460 Level 2 inputs: Securities held to maturity 459,897 446,287 514,844 518,165 Restricted equity securities 17,250 N/A 16,956 N/A Level 3 inputs: Loans, net 3,995,833 3,987,841 2,984,842 2,992,225 Financial liabilities: Level 2 inputs: Deposits 5,093,117 5,088,024 4,009,131 4,006,620 Other borrowings 282,831 282,831 122,166 122,166 Level 3 inputs: Junior subordinated debt 56,996 58,930 56,858 58,466 Contract Fair Contract Fair Amount Value Amount Value Off-balance Level 3 inputs: Commitments $ 1,225,542 $ 12,255 $ 933,542 $ 9,335 Standby letters of credit 11,277 113 13,075 131 Overdraft privilege commitments 107,956 1,080 98,260 983

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2018
Banking and Thrift [Abstract]
Regulatory Matters	Note 19 - Regulatory Matters The Company is subject to various regulatory capital requirements administered by federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company’s consolidated financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company must meet specific capital guidelines that involve quantitative measures of the Company’s assets, liabilities and certain off-balance-sheet Quantitative measures established by regulation to ensure capital adequacy require the Company to maintain minimum amounts and ratios (set forth in the table below) of total, Tier 1, and common equity Tier 1 capital to risk-weighted assets, and of Tier 1 capital to average assets. The following tables present actual and required capital ratios as of September 30, 2018 and December 31, 2017 for the Company and the Bank under Basel III Capital Rules. The minimum capital amounts presented include the minimum required capital levels as of September 30, 2018 and December 31, 2017 based on the then phased-in phased-in. Minimum Capital Minimum Capital Required to be Required – Basel III Required – Basel III Considered Well Actual Phase-in Fully Phased In Capitalized Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) As of September 30, 2018: Total Capital (to Risk Weighted Assets): Consolidated $ 664,197 13.90 % $ 471,956 9.875 % $ 501,826 10.50 % N/A N/A Tri Counties Bank $ 658,075 13.77 % $ 471,784 9.875 % $ 501,643 10.50 % $ 477,756 10.00 % Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 630,294 13.19 % $ 376,370 7.875 % $ 406,240 8.50 % N/A N/A Tri Counties Bank $ 624,172 13.06 % $ 376,233 7.875 % $ 406,092 8.50 % $ 382,205 8.00 % Common equity Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 575,010 12.03 % $ 304,680 6.375 % $ 334,551 7.00 % N/A N/A Tri Counties Bank $ 624,172 13.06 % $ 304,569 6.375 % $ 334,429 7.00 % $ 310,541 6.50 % Tier 1 Capital (to Average Assets): Consolidated $ 630,294 10.66 % $ 236,503 4.000 % $ 236,503 4.00 % N/A N/A Tri Counties Bank $ 624,172 10.56 % $ 236,496 4.000 % $ 236,496 4.00 % $ 295,620 5.00 % Minimum Capital Minimum Capital Required to be Required – Basel III Required – Basel III Considered Well Actual Phase-in Fully Phased In Capitalized Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) As of December 31, 2017: Total Capital (to Risk Weighted Assets): Consolidated $ 528,805 14.07 % $ 347,694 9.250 % $ 394,679 10.50 % N/A N/A Tri Counties Bank $ 525,384 13.98 % $ 347,535 9.250 % $ 394,499 10.50 % $ 375,713 10.00 % Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 495,318 13.18 % $ 272,517 7.250 % $ 319,502 8.50 % N/A N/A Tri Counties Bank $ 491,897 13.09 % $ 272,392 7.250 % $ 319,356 8.50 % $ 300,570 8.00 % Common equity Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 440,643 11.72 % $ 216,134 5.750 % $ 263,120 7.00 % N/A N/A Tri Counties Bank $ 491,897 13.09 % $ 216,035 5.750 % $ 262,999 7.00 % $ 244,214 6.50 % Tier 1 Capital (to Average Assets): Consolidated $ 495,318 10.80 % $ 183,400 4.000 % $ 183,400 4.00 % N/A N/A Tri Counties Bank $ 491,897 10.73 % $ 183,394 4.000 % $ 183,394 4.00 % $ 229,243 5.00 % As of September 30, 2018, capital levels at the Company and the Bank exceed all capital adequacy requirements under the Basel III Capital Rules on a fully phased-in Beginning January 1, 2016, the Basel III Capital Rules implemented a requirement for all banking organizations to maintain a capital conservation buffer above the minimum risk-based capital requirements in order to avoid certain limitations on capital distributions, stock repurchases and discretionary bonus payments to executive officers. The capital conservation buffer is exclusively composed of common equity tier 1 capital, and it applies to each of the risk-based capital ratios but not the leverage ratio. At September 30, 2018, the Company and the Bank are in compliance with the capital conservation buffer requirement. The three risk-based capital ratios will increase by 0.625% each year through 2019, at which point, the common equity tier 1 risk-based, tier 1 risk-based and total risk-based capital ratio minimums will be 7.0%, 8.5% and 10.5%, respectively.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation TriCo Bancshares (the “Company” or “we”) is a California corporation organized to act as a bank holding company for Tri Counties Bank (the “Bank”). The Company and the Bank are headquartered in Chico, California. The Bank is a California-chartered bank that is engaged in the general commercial banking business in 29 California counties. The Bank operates from 69 traditional branches, 9 in-store The consolidated financial statements are prepared in accordance with accounting policies generally accepted in the United States of America and general practices in the banking industry. All adjustments necessary for a fair presentation of these consolidated financial statements have been included and are of a normal and recurring nature. The financial statements include the accounts of the Company. All inter-company accounts and transactions have been eliminated in consolidation. For financial reporting purposes, the Company’s investments in the Capital Trusts of $1,741,000 are accounted for under the equity method and, accordingly, are not consolidated and are included in other assets on the consolidated balance sheet. The subordinated debentures issued and guaranteed by the Company and held by the Capital Trusts are reflected as debt on the Company’s consolidated balance sheet.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires Management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the rules and regulatinos of the Securities and Exchange Commission. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidtated financial statements and notes thereto included in the Company’s Annua Report on Form 10-K
Significant Group Concentration of Credit Risk	Significant Group Concentration of Credit Risk The Company grants agribusiness, commercial, consumer, and residential loans to customers located throughout northern and central California. The Company has a diversified loan portfolio within the business segments located in this geographical area. The Company currently classifies all its operation into one business segment that it denotes as community banking.
Geographical Descriptions	Geographical Descriptions For the purpose of describing the geographical location of the Company’s loans, the Company has defined northern California as that area of California north of, and including, Stockton; central California as that area of the state south of Stockton, to and including, Bakersfield; and southern California as that area of the state south of Bakersfield.
Business Combinations	Business Combinations The Company accounts for acquisitions of businesses using the acquisition method of accounting. Under the acquisition method, assets acquired and liabilities assumed are recorded at their estimated fair values at the date of acquisition. Management utilizes various valuation techniques including discounted cash flow analyses to determine these fair values. Any excess of the purchase price over amounts allocated to the acquired assets, including identifiable intangible assets, and liabilities assumed is recorded as goodwill.
Cash and Cash Equivalents	Cash and Cash Equivalents Net cash flows are reported for loan and deposit transactions and other borrowings. For purposes of the consolidated statement of cash flows, cash, due from banks with maturities less than 90 days, interest-earning deposits in other banks, and Federal funds sold are considered to be cash equivalents.
Revenue Recognition	Revenue Recognition The Company records revenue from contracts with customers in accordance with Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (“Topic 606”). Under Topic 606, the Company must identify the contract with a customer, identify the performance obligations in the contract, determine the transaction price, allocate the transaction price to the performance obligations in the contract, and recognize revenue when (or as) the Company satisfies a performance obligation. Most of our revenue-generating transactions are not subject to Topic 606, including revenue generated from financial instruments, such as our loans and investment securities. In addition, certain noninterest income streams such as fees associated with mortgage servicing rights, financial guarantees, derivatives, and certain credit card fees are also not in scope of the new guidance. The Company’s noninterest revenue streams are largely based on transactional activity, or standard month-end month-end
Accounting Standards Adopted in 2018	Accounting Standards Adopted in 2018 FASB Accounting Standards Update (ASU) No. 2014- 09, Revenue from Contracts with Customers (Topic 606): 2014-09 2014-09 2014-09 2014-09 In January 2016, the FASB issued ASU No. 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.” available-for-sale No. 2016-01 Fair Value Measurement FASB issued ASU No. 2016-18, Statement of Cash Flows - Restricted Cash (Topic 230). ASU 2016-18 beginning-of-period end-of-period ASU 2016-18 FASB issued ASU No. 2017-01, Business Combinations - Clarifying the Definition of a Business (Topic 805). ASU 2017-01 ASU 2017-01 ASU 2017-01 FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715). 2017-07 ASU 2017-07 FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718). ASU 2017-09 ASU 2017-09, ASU 2017-09 FASB issued ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220). 2018-02 2018-02 2018-02
Accounting Standards Pending Adoption	Accounting Standards Pending Adoption FASB issued ASU No. 2016-02, Leases (Topic 842) ASU 2016-2, on-balance ASU 2016-02 No. 2018-10 2018-11. No. 2016-02, 2018-10 2018-11. FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326) FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other: Simplifying the Test for Goodwill Impairment (Topic 350): 2017-04 ASU 2017-04 FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Topic 310). ASU 2017-08 non-pooled ASU 2017-08 ASU 2017-08 In August 2018, the FASB issued ASU No. 2018-13, “Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement.” No. 2018-13 No. 2018-13 In August 2018, the FASB issued ASU No. 2018-14, “Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans.” 2018-14 2018-14

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Schedule of Business Acquisition Pro-forma financial Information	The unaudited pro forma financial information is not necessarily indicative of the results of operations that would have occurred had the transaction been effected on the assumed date. Three months ended Nine months ended September 30, September 30, September 30, September 30, ( in thousands, except per share data) Summarized proforma income statement data: Net interest income $ 61,259 $ 57,329 $ 178,434 $ 168,363 Provision for (benefit from) loan losses 2,651 765 1,374 (1,728 ) Noninterest income 12,288 13,902 38,517 40,537 Noninterest expense (40,850 ) (45,983 ) (135,048 ) (135,218 ) Income before taxes 30,046 24,483 80,529 75,410 Income taxes 8,384 9,055 22,996 27,436 Net income $ 21,662 $ 15,428 $ 57,533 $ 47,974 Basic earnings per share $ 0.72 $ 0.51 $ 1.76 $ 1.58 Diluted earnings per share $ 0.71 $ 0.50 $ 1.74 $ 1.56
Schedule of Fair Value of Consideration Transferred, Identifiable Net Assets Acquired and Resulting Goodwill	The following table summarizes the consideration paid for FNBB and the amounts of assets acquired and liabilities assumed that were recorded at the acquisition date (in thousands). FNB Bancorp Fair value of consideration transferred: Fair value of shares issued $ 284,437 Cash consideration 6,695 Total fair value of consideration transferred 291,132 Assets acquired: Cash and cash equivalents 37,308 Securities available for sale 335,667 Restricted equity securities 7,723 Loans 834,683 Premises and equipment 30,522 Cash value of life insurance 16,817 Core deposit intangible 27,605 Other assets 16,214 Total assets acquired 1,306,539 Liabilities assumed: Deposits 991,935 Other liabilities 15,133 Short-term borrowings - Federal Home Loan Bank 165,000 Total liabilities assumed 1,172,068 Total net assets acquired 134,471 Goodwill recognized $ 156,661

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments Schedule [Abstract]
Amortized Cost and Estimated Fair Values of Investments in Debt Securities	The amortized cost and estimated fair values of investments in debt securities are summarized in the following tables: September 30, 2018 Amortized Gross Gross Estimated Fair (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 666,021 163 (27,308 ) $ 638,876 Obligations of states and political subdivisions 129,072 107 (5,759 ) 123,420 Corporate bonds 4,368 65 (2 ) 4,431 Asset backed securities 289,550 181 (498 ) 289,233 Total debt securities available for sale $ 1,089,011 $ 516 $ (33,567 ) $ 1,055,960 Debt Securities Held to Maturity Obligations of U.S. government agencies $ 445,309 $ 88 $ (13,361 ) $ 432,036 Obligations of states and political subdivisions 14,588 58 (395 ) 14,251 Total debt securities held to maturity $ 459,897 $ 146 $ (13,756 ) $ 446,287 December 31, 2017 Amortized Gross Gross Estimated Fair (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 609,695 $ 695 $ (5,601 ) $ 604,789 Obligations of states and political subdivisions 121,597 1,888 (329 ) 123,156 Total debt securities available for sale $ 731,292 $ 2,583 $ (5,930 ) $ 727,945 Debt Securities Held to Maturity Obligations of U.S. government agencies $ 500,271 $ 5,101 $ (1,889 ) $ 503,483 Obligations of states and political subdivisions 14,573 146 (37 ) 14,682 Total debt securities held to maturity $ 514,844 $ 5,247 $ (1,926 ) $ 518,165
Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity	For purposes of the following table, the entire outstanding balance of these mortgage-backed securities issued by U.S. government corporations and agencies is categorized based on final maturity date. Debt Securities Available for Sale Held to Maturity (In thousands) Amortized Estimated Fair Amortized Estimated Fair Due in one year $ 2,435 $ 2,434 $ — $ — Due after one year through five years 12,486 12,501 1,231 1,240 Due after five years through ten years 17,764 17,740 25,955 25,210 Due after ten years 1,056,326 1,023,285 432,711 419,837 Totals $ 1,089,011 $ 1,055,960 $ 459,897 $ 446,287
Gross Unrealized Losses on Debt Securities	Gross unrealized losses on debt securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, were as follows: Less than 12 months 12 months or more Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized September 30, 2018 (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 323,972 $ (10,839 ) $ 311,035 $ (16,469 ) $ 635,007 $ (27,308 ) Obligations of states and political subdivisions 85,668 (3,659 ) 18,323 (2,100 ) 103,991 (5,759 ) Corporate bonds 1,969 (2 ) — — 1,969 (2 ) Asset backed securities 79,943 (498 ) — — 79,943 (498 ) Total debt securities available for sale $ 491,552 $ (14,998 ) $ 329,358 $ (18,569 ) $ 820,910 $ (33,567 ) Debt Securities Held to Maturity Obligations of U.S. government agencies $ 307,432 $ (7,693 ) $ 109,312 $ (5,668 ) $ 416,744 $ (13,361 ) Obligations of states and political subdivisions 8,971 (230 ) 3,076 (165 ) 12,047 (395 ) Total debt securities held to maturity $ 316,403 $ (7,923 ) $ 112,388 $ (5,833 ) $ 428,791 $ (13,756 ) Less than 12 months 12 months or more Total Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized December 31, 2017 (in thousands) Debt Securities Available for Sale Obligations of U.S. government agencies $ 284,367 $ (2,176 ) $ 166,338 $ (3,425 ) $ 450,705 $ (5,601 ) Obligations of states and political subdivisions 4,904 (35 ) 17,085 (294 ) 21,989 (329 ) Total securities available for sale $ 289,271 $ (2,211 ) $ 183,423 $ (3,719 ) $ 472,694 $ (5,930 ) Debt Securities Held to Maturity Obligations of U.S. government agencies $ 93,017 $ (567 ) $ 95,367 $ (1,322 ) $ 188,384 $ (1,889 ) Obligations of states and political subdivisions 1,488 (7 ) 2,637 (30 ) 4,125 (37 ) Total debt securities held to maturity $ 94,505 $ (574 ) $ 98,004 $ (1,352 ) $ 192,509 $ (1,926 )

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Summary of Loan Balances	A summary of loan balances follows (in thousands): September 30, 2018 Originated PNCI PCI Total Mortgage loans on real estate: Residential 1-4 $ 340,515 $ 182,201 $ 1,698 $ 524,414 Commercial 1,863,604 736,299 7,885 2,607,788 Total mortgage loans on real estate 2,204,119 918,500 9,583 3,132,202 Consumer: Home equity lines of credit 284,956 44,881 1,299 331,136 Home equity loans 35,556 4,690 447 40,693 Other 26,294 23,120 42 49,456 Total consumer loans 346,806 72,691 1,788 421,285 Commercial 234,741 52,479 2,427 289,647 Construction: Residential 81,533 33,041 — 114,574 Commercial 63,508 6,220 — 69,728 Total construction 145,041 39,261 — 184,302 Total loans, net of deferred loan fees and discounts $ 2,930,707 $ 1,082,931 $ 13,798 $ 4,027,436 Total principal balance of loans owed, net of charge-offs $ 2,940,897 $ 1,120,654 $ 21,007 $ 4,082,558 Unamortized net deferred loan fees (10,190 ) — — (10,190 ) Discounts to principal balance of loans owed, net of charge-offs — (37,723 ) (7,209 ) (44,932 ) Total loans, net of unamortized deferred loan fees and discounts $ 2,930,707 $ 1,082,931 $ 13,798 $ 4,027,436 Allowance for loan losses $ (30,927 ) $ (566 ) $ (110 ) $ (31,603 ) December 31, 2017 Originated PNCI PCI Total Mortgage loans on real estate: Residential 1-4 $ 320,522 $ 63,519 $ 1,385 $ 385,426 Commercial 1,690,510 215,823 8,563 1,914,896 Total mortgage loan on real estate 2,011,032 279,342 9,948 2,300,322 Consumer: Home equity lines of credit 269,942 16,248 2,498 288,688 Home equity loans 39,848 2,698 485 43,031 Other 22,859 2,251 45 25,155 Total consumer loans 332,649 21,197 3,028 356,874 Commercial 209,437 8,391 2,584 220,412 Construction: Residential 67,920 10 — 67,930 Commercial 69,364 263 — 69,627 Total construction 137,284 273 — 137,557 Total loans, net of deferred loan fees and discounts $ 2,690,402 $ 309,203 $ 15,560 $ 3,015,165 Total principal balance of loans owed, net of charge-offs $ 2,699,053 $ 316,238 $ 23,181 $ 3,038,472 Unamortized net deferred loan fees (8,651 ) — — (8,651 ) Discounts to principal balance of loans owed, net of charge-offs — (7,035 ) (7,621 ) (14,656 ) Total loans, net of unamortized deferred loan fees and discounts $ 2,690,402 $ 309,203 $ 15,560 $ 3,015,165 Allowance for loan losses $ (29,122 ) $ (929 ) $ (272 ) $ (30,323 )
Change in Accretable Yield for PCI	The following is a summary of the change in accretable yield for PCI loans during the periods indicated (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Change in accretable yield: Balance at beginning of period $ 3,996 $ 7,956 $ 4,262 $ 10,348 Accretion to interest income (253 ) (594 ) (769 ) (2,554 ) Reclassification (to) from nonaccretable difference (47 ) (2,893 ) 203 (3,325 ) Balance at end of period $ 3,696 $ 4,469 $ 3,696 $ 4,469

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Summary of Activity in Allowance for Loan Losses, and Ending Balance of Loans, Net of Unearned Fees for Periods Indicated	The following tables summarize the activity in the allowance for loan losses, and ending balance of loans, net of unearned fees for the periods indicated. Allowance for Loan Losses – Three Months Ended September 30, 2018 (in thousands) Beginning Charge-offs Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 1,991 $ (25 ) $ — $ 434 $ 2,400 Commercial 11,607 — 15 1,257 12,879 Total mortgage loans on real estate 13,598 (25 ) 15 1,691 15,279 Consumer: Home equity lines of credit 5,048 (172 ) 151 194 5,221 Home equity loans 1,532 (23 ) 139 (55 ) 1,593 Other 557 (229 ) 63 309 700 Total consumer loans 7,137 (424 ) 353 448 7,514 Commercial 6,378 (693 ) 202 337 6,224 Construction: Residential 1,434 — — 192 1,626 Commercial 977 — — (17 ) 960 Total construction 2,411 — — 175 2,586 Total $ 29,524 $ (1,142 ) $ 570 $ 2,651 $ 31,603 Allowance for Loan Losses – Nine Months Ended September 30, 2018 (in thousands) Beginning Charge-offs Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 2,317 $ (77 ) $ — $ 160 $ 2,400 Commercial 11,441 (15 ) 51 1,402 12,879 Total mortgage loans on real estate 13,758 (92 ) 51 1,562 15,279 Consumer: Home equity lines of credit 5,800 (276 ) 677 (980 ) 5,221 Home equity loans 1,841 (23 ) 176 (401 ) 1,593 Other 586 (597 ) 208 503 700 Total consumer loans 8,227 (896 ) 1,061 (878 ) 7,514 Commercial 6,512 (952 ) 331 333 6,224 Construction: Residential 1,184 — — 442 1,626 Commercial 642 — — 318 960 Total construction 1,826 — — 760 2,586 Total $ 30,323 $ (1,940 ) $ 1,443 $ 1,777 $ 31,603 Allowance for Loan Losses – As of September 30, 2018 (in thousands) Individually Loans pooled Loans acquired Total allowance Mortgage loans on real estate: Residential 1-4 $ 57 $ 2,313 $ 30 $ 2,400 Commercial 268 12,552 59 12,879 Total mortgage loans on real estate 325 14,865 89 15,279 Consumer: Home equity lines of credit 168 5,046 7 5,221 Home equity loans 175 1,418 — 1,593 Other 103 597 — 700 Total consumer loans 446 7,061 7 7,514 Commercial 1,857 4,353 14 6,224 Construction: Residential — 1,626 — 1,626 Commercial — 960 — 960 Total construction — 2,586 — 2,586 Total $ 2,628 $ 28,865 $ 110 $ 31,603 Loans, Net of Unearned fees – As of September 30, 2018 (in thousands) Individually Loans pooled Loans acquired Total loans, net Mortgage loans on real estate: Residential 1-4 $ 4,781 $ 517,935 $ 1,698 $ 524,414 Commercial 13,244 2,586,659 7,885 2,607,788 Total mortgage loans on real estate 18,025 3,104,594 9,583 3,132,202 Consumer: Home equity lines of credit 2,188 327,649 1,299 331,136 Home equity loans 2,406 37,840 447 40,693 Other 243 49,171 42 49,456 Total consumer loans 4,837 414,660 1,788 421,285 Commercial 4,632 282,588 2,427 289,647 Construction: Residential — 114,574 — 114,574 Commercial — 69,728 — 69,728 Total construction — 184,302 — 184,302 Total $ 27,494 $ 3,986,144 $ 13,798 $ 4,027,436 Allowance for Loan Losses – Year Ended December 31, 2017 (in thousands) Beginning Charge-offs Recoveries Provision Ending Mortgage loans on real estate: Residential 1-4 $ 2,748 $ (60 ) $ — $ (371 ) $ 2,317 Commercial 11,517 (186 ) 397 (287 ) 11,441 Total mortgage loans on real estate 14,265 (246 ) 397 (658 ) 13,758 Consumer: Home equity lines of credit 7,044 (98 ) 698 (1,844 ) 5,800 Home equity loans 2,644 (332 ) 242 (713 ) 1,841 Other 622 (1,186 ) 375 775 586 Total consumer loans 10,310 (1,616 ) 1,315 (1,782 ) 8,227 Commercial 5,831 (1,444 ) 428 1,697 6,512 Construction: Residential 1,417 (1,104 ) — 871 1,184 Commercial 680 — 1 (39 ) 642 Total construction 2,097 (1,104 ) 1 832 1,826 Total $ 32,503 $ (4,410 ) $ 2,141 $ 89 $ 30,323 Allowance for Loan Losses – As of December 31, 2017 (in thousands) Individually Loans pooled Loans acquired Total allowance Mortgage loans on real estate: Residential 1-4 $ 230 $ 1,932 $ 155 $ 2,317 Commercial 30 11,351 60 11,441 Total mortgage loans on real estate 260 13,283 215 13,758 Consumer: Home equity lines of credit 427 5,356 17 5,800 Home equity loans 107 1,734 — 1,841 Other 57 529 — 586 Total consumer loans 591 7,619 17 8,227 Commercial 1,848 4,624 40 6,512 Construction: Residential — 1,184 — 1,184 Commercial — 642 — 642 Total construction — 1,826 — 1,826 Total $ 2,699 $ 27,352 $ 272 $ 30,323 Loans, Net of Unearned fees – As of December 31, 2017 (in thousands) Individually Loans pooled Loans acquired Total loans, net Mortgage loans on real estate: Residential 1-4 $ 5,298 $ 378,743 $ 1,385 $ 385,426 Commercial 13,911 1,892,422 8,563 1,914,896 Total mortgage loans on real estate 19,209 2,271,165 9,948 2,300,322 Consumer: Home equity lines of credit 2,688 283,502 2,498 288,688 Home equity loans 1,470 41,076 485 43,031 Other 257 24,853 45 25,155 Total consumer loans 4,415 349,431 3,028 356,874 Commercial 4,470 213,358 2,584 220,412 Construction: Residential 140 67,790 — 67,930 Commercial — 69,627 — 69,627 Total construction 140 137,417 — 137,557 Total $ 28,234 $ 2,971,371 $ 15,560 $ 3,015,165 Allowance for Loan Losses – Three Months Ended September 30, 2017 (in thousands) Beginning Charge- Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 2,495 $ (60 ) $ — $ (217 ) $ 2,218 Commercial 10,119 (20 ) 238 1,033 11,370 Total mortgage loans on real estate 12,614 (80 ) 238 816 13,588 Consumer: Home equity lines of credit 6,156 (14 ) 189 (610 ) 5,721 Home equity loans 2,354 (94 ) 121 (390 ) 1,991 Other 645 (349 ) 91 203 590 Total consumer loans 9,155 (457 ) 401 (797 ) 8,302 Commercial 4,729 (291 ) 61 303 4,802 Construction: Residential 1,179 (33 ) — 284 1,430 Commercial 466 — — 159 625 Total construction 1,645 (33 ) — 443 2,055 Total $ 28,143 $ (861 ) $ $ 765 $ 28,747 Allowance for Loan Losses – Nine Months Ended September 30, 2017 (in thousands) Beginning Charge-offs Recoveries Provision Ending Balance Mortgage loans on real estate: Residential 1-4 $ 2,748 $ (60 ) $ $ (470 ) $ 2,218 Commercial 11,517 (170 ) 365 (342 ) 11,370 Total mortgage loans on real estate 14,265 (230 ) 365 (812 ) 13,588 Consumer: Home equity lines of credit 7,044 (98 ) 487 (1,712 ) 5,721 Home equity loans 2,644 (331 ) 146 (468 ) 1,991 Other 622 (831 ) 300 499 590 Total consumer loans 10,310 (1,260 ) 933 (1,681 ) 8,302 Commercial 5,831 (1,188 ) 315 (156 ) 4,802 Construction: Residential 1,417 (1,104 ) — 1,117 1,430 Commercial 680 — 1 (56 ) 625 Total construction 2,097 (1,104 ) 1 1,061 2,055 Total $ 32,503 $ (3,782 ) $ 1,614 $ (1,588 ) $ 28,747 Allowance for Loan Losses – As of September 30, 2017 (in thousands) Individually Loans pooled Loans acquired Total allowance Mortgage loans on real estate: Residential 1-4 $ 240 $ 1,978 $ — $ 2,218 Commercial 73 11,022 275 11,370 Total mortgage loans on real estate 313 13,000 275 13,588 Consumer: Home equity lines of credit 363 5,346 12 5,721 Home equity loans 111 1,880 — 1,991 Other 77 513 — 590 Total consumer loans 551 7,739 12 8,302 Commercial 1,276 3,526 — 4,802 Construction: Residential — 1,430 — 1,430 Commercial — 625 — 625 Total construction — 2,055 — 2,055 Total $ 2,140 $ 26,320 $ 287 $ 28,747 Loans, Net of Unearned fees – As of September 30, 2017 (in thousands) Individually Loans pooled Loans acquired Total Loans Mortgage loans on real estate: Residential 1-4 $ 5,027 $ 384,640 $ 1,405 $ 391,072 Commercial 19,788 1,775,843 8,171 1,803,802 Total mortgage loans on real estate 24,815 2,160,483 9,576 2,194,874 Consumer: Home equity lines of credit 2,219 284,335 2,952 289,506 Home equity loans 1,842 42,454 737 45,033 Other 267 26,470 44 26,781 Total consumer loans 4,328 353,259 3,733 361,320 Commercial 2,938 221,846 2,695 227,479 Construction: Residential 144 74,976 — 75,120 Commercial — 72,820 — 72,820 Total construction 144 147,796 — 147,940 Total $ 32,225 $ 2,883,384 $ 16,004 $ 2,931,613
Schedule Credit Quality Indicators	The following tables present ending loan balances by loan category and risk grade for the periods indicated: Credit Quality Indicators Originated Loans – As of September 30, 2018 (in thousands) Pass Special Substandard Doubtful / Loss Total Originated Mortgage loans on real estate: Residential 1-4 $ 334,902 $ 1,690 $ 3,923 $ — $ 340,515 Commercial 1,821,995 28,747 12,862 — 1,863,604 Total mortgage loans on real estate 2,156,897 30,437 16,785 — 2,204,119 Consumer: Home equity lines of credit 281,480 1,747 1,729 — 284,956 Home equity loans 32,242 1,006 2,308 — 35,556 Other 25,885 334 75 — 26,294 Total consumer loans 339,607 3,087 4,112 — 346,806 Commercial 220,328 9,942 4,471 — 234,741 Construction: Residential 81,235 32 266 — 81,533 Commercial 62,660 848 — — 63,508 Total construction 143,895 880 266 — 145,041 Total loans $ 2,860,727 $ 44,346 $ 25,634 $ — $ 2,930,707 Credit Quality Indicators PNCI Loans – As of September 30, 2018 (in thousands) Pass Special Substandard Doubtful / Loss Total PNCI Mortgage loans on real estate: Residential 1-4 $ 179,634 $ 880 $ 1,687 $ — $ 182,201 Commercial 729,261 3,478 3,560 — 736,299 Total mortgage loans on real estate 908,895 4,358 5,247 — 918,500 Consumer: Home equity lines of credit 43,406 826 649 — 44,881 Home equity loans 4,471 116 103 — 4,690 Other 23,083 32 5 — 23,120 Total consumer loans 70,960 974 757 — 72,691 Commercial 51,633 734 112 — 52,479 Construction: Residential 33,041 — — — 33,041 Commercial 6,220 — — — 6,220 Total construction 39,261 — — — 39,261 Total loans $ 1,070,749 $ 6,066 $ 6,116 $ — $ 1,082,931 Credit Quality Indicators Originated Loans – As of December 31, 2017 (in thousands) Pass Special Substandard Doubtful / Loss Total Originated Mortgage loans on real estate: Residential 1-4 $ 315,120 $ 2,234 $ 3,168 $ — $ 320,522 Commercial 1,649,333 18,434 22,743 — 1,690,510 Total mortgage loans on real estate 1,964,453 20,668 25,911 — 2,011,032 Consumer: Home equity lines of credit 265,345 2,558 2,039 — 269,942 Home equity loans 37,428 800 1,620 — 39,848 Other 22,432 272 155 — 22,859 Total consumer loans 325,205 3,630 3,814 — 332,649 Commercial 195,208 9,492 4,737 — 209,437 Construction: Residential 67,813 — 107 — 67,920 Commercial 64,492 4,872 — — 69,364 Total construction 132,305 4,872 107 — 137,284 Total loans $ 2,617,171 $ 38,662 $ 34,569 $ — $ 2,690,402 Credit Quality Indicators PNCI Loans – As of December 31, 2017 (in thousands) Pass Special Substandard Doubtful / Loss Total PNCI Mortgage loans on real estate: Residential 1-4 $ 61,411 $ 218 $ 1,890 $ — $ 63,519 Commercial 203,751 11,513 559 — 215,823 Total mortgage loans on real estate 265,162 11,731 2,449 — 279,342 Consumer: Home equity lines of credit 14,866 450 932 — 16,248 Home equity loans 2,433 188 77 — 2,698 Other 2,207 38 6 — 2,251 Total consumer loans 19,506 676 1,015 — 21,197 Commercial 8,390 1 — — 8,391 Construction: Residential 10 — — — 10 Commercial 263 — — — 263 Total construction 273 — — — 273 Total $ 293,331 $ 12,408 $ 3,464 $ — $ 309,203
Analysis of Past Due Loans	The following table shows the ending balance of current and past due originated loans by loan category as of the date indicated: Analysis of Originated Past Due Loans - As of September 30, 2018 ³ (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 $ 275 $ 749 $ 738 $ 1,762 $ 338,753 $ 340,515 $ — Commercial 499 150 117 766 1,862,838 1,863,604 — Total mortgage loans on real estate 774 899 855 2,528 2,201,591 2,204,119 — Consumer: Home equity lines of credit 1,450 97 112 1,659 283,297 284,956 — Home equity loans 527 293 411 1,231 34,325 35,556 — Other 262 24 — 286 26,008 26,294 — Total consumer loans 2,239 414 523 3,176 343,630 346,806 — Commercial 1,010 134 1,309 2,453 232,288 234,741 — Construction: Residential 488 — — 488 81,045 81,533 — Commercial — — — — 63,508 63,508 — Total construction 488 — — 488 144,553 145,041 — Total originated loans $ 4,511 $ 1,447 $ 2,687 $ 8,645 $ 2,922,062 $ 2,930,707 $ — The following table shows the ending balance of current and past due PNCI loans by loan category as of the date indicated: Analysis of PNCI Past Due Loans - As of September 30, 2018 ³ (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 $ $ 397 $ 163 $ 560 $ 181,641 $ 182,201 $ — Commercial 992 18 949 1,959 734,340 736,299 949 Total mortgage loans on real estate 992 415 1,112 2,519 915,981 918,500 949 Consumer: Home equity lines of credit 613 192 227 1,032 43,849 44,881 99 Home equity loans 262 — 16 278 4,412 4,690 — Other 242 — — 242 22,878 23,120 — Total consumer loans 1,117 192 243 1,552 71,139 72,691 99 Commercial 30 472 — 502 51,977 52,479 — Construction: Residential — — — — 33,041 33,041 — Commercial — — — — 6,220 6,220 — Total construction — — — — 39,261 39,261 — Total PNCI loans $ 2,139 $ 1,079 $ 1,355 $ 4,573 $ 1,078,358 $ 1,082,931 $ 1,048 The following table shows the ending balance of current and past due originated loans by loan category as of the date indicated: Analysis of Originated Past Due Loans - As of December 31, 2017 ³ (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 $ 1,740 $ 510 $ 243 $ 2,493 $ 318,029 $ 320,522 $ — Commercial 158 987 — 1,145 1,689,365 1,690,510 — Total mortgage loans on real estate 1,898 1,497 243 3,638 2,007,394 2,011,032 — Consumer: Home equity lines of credit 528 48 372 948 268,994 269,942 — Home equity loans 511 107 373 991 38,857 39,848 — Other 56 36 3 95 22,764 22,859 — Total consumer loans 1,095 191 748 2,034 330,615 332,649 — Commercial 956 738 1,527 3,221 206,216 209,437 — Construction: Residential 34 — — 34 67,886 67,920 — Commercial — — — — 69,364 69,364 — Total construction 34 — — 34 137,250 137,284 — Total loans $ 3,983 $ 2,426 $ 2,518 $ 8,927 $ 2,681,475 $ 2,690,402 $ — The following table shows the ending balance of current and past due PNCI loans by loan category as of the date indicated: Analysis of PNCI Past Due Loans - As of December 31, 2017 > 90 Days (in thousands) 30-59 days 60-89 days > 90 days Total Past Current Total Mortgage loans on real estate: Residential 1-4 family $ 1,495 $ 90 $ 109 $ 1,694 $ 61,825 $ 63,519 $ 81 Commercial 70 — — 70 215,753 215,823 — Total mortgage loans on real estate 1,565 90 109 1,764 277,578 279,342 81 Consumer: Home equity lines of credit 298 228 330 856 15,392 16,248 200 Home equity loans 30 — — 30 2,668 2,698 — Other 6 26 — 32 2,219 2,251 — Total consumer loans 334 254 330 918 20,279 21,197 200 Commercial — — — — 8,391 8,391 — Construction: Residential — — — — 10 10 — Commercial — — — — 263 263 — Total construction — — — — 273 273 — Total loans $ 1,899 $ 344 $ 439 $ 2,682 $ 306,521 $ 309,203 $ 281
Schedule of Non Accrual Loans	The following table shows the ending balance of nonaccrual originated and PNCI loans by loan category as of the date indicated: Non Accrual Loans As of September 30, 2018 As of December 31, 2017 (in thousands) Originated PNCI Total Originated PNCI Total Mortgage loans on real estate: Residential 1-4 family $ 2,813 $ 1,219 $ 4,032 $ 1,725 $ 1,012 $ 2,737 Commercial 7,876 305 8,181 8,144 — 8,144 Total mortgage loans on real estate 10,689 1,524 12,213 9,869 1,012 10,881 Consumer: Home equity lines of credit 725 568 1,293 811 402 1,213 Home equity loans 1,933 50 1,983 1,106 44 1,150 Other 3 5 8 7 5 12 Total consumer loans 2,661 623 3,284 1,924 451 2,375 Commercial 3,737 — 3,737 3,669 — 3,669 Construction: Residential — — — — — — Commercial — — — — — — Total construction — — — — — — Total non accrual loans $ 17,087 $ 2,147 $ 19,234 $ 15,462 $ 1,463 $ 16,925
Impaired Loans	The following tables show the recorded investment (financial statement balance), unpaid principal balance, average recorded investment, and interest income recognized for impaired Originated and PNCI loans, segregated by those with no related allowance recorded and those with an allowance recorded for the periods indicated. Impaired Originated Loans – As of, or for the Nine Months Ended, September 30, 2018 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 4,185 $ 3,251 $ 311 $ 3,562 $ 57 $ 3,883 $ 67 Commercial 12,553 9,619 2,370 11,989 268 11,549 208 Total mortgage loans on real estate 16,738 12,870 2,681 15,551 325 15,432 275 Consumer: Home equity lines of credit 1,444 1,346 59 1,405 19 1,410 32 Home equity loans 2,554 1,960 157 2,117 30 1,753 24 Other 3 — 3 3 3 3 — Total consumer loans 4,001 3,306 219 3,525 52 3,166 56 Commercial 4,868 2,135 2,497 4,632 1,857 4,626 78 Construction: Residential — — — — — 68 — Commercial — — — — — — — Total construction — — — — — 68 — Total $ 25,607 $ 18,311 $ 5,397 $ 23,708 $ 2,234 $ 23,292 $ 409 Impaired PNCI Loans – As of, or for the Nine Months Ended, September 30, 2018 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 1,302 $ 1,219 $ — $ 1,219 $ — $ 1,275 $ — Commercial 1,255 1,255 — 1,255 — 627 58 Total mortgage loans on real estate 2,557 2,474 — 2,474 — 1,902 58 Consumer: Home equity lines of credit 852 625 158 783 149 909 13 Home equity loans 296 50 239 289 145 287 9 Other 240 — 240 240 100 257 7 Total consumer loans 1,388 675 637 1,312 394 1,453 29 Commercial — — — — — — — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total $ 3,945 $ 3,149 $ 637 $ 3,786 $ 394 $ 3,355 $ 87 Impaired Originated Loans – As of, or for the Twelve Months Ended, December 31, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 4,023 $ 2,058 $ 1,881 $ 3,939 $ 230 $ 3,501 $ 143 Commercial 14,186 13,101 810 13,911 30 13,851 645 Total mortgage loans on real estate 18,209 15,159 2,691 17,850 260 17,352 788 Consumer: Home equity lines of credit 1,581 1,093 401 1,494 111 1,702 47 Home equity loans 1,627 1,107 198 1,305 10 1,193 24 Other 52 4 3 7 3 20 — Total consumer loans 3,260 2,204 602 2,806 124 2,915 71 Commercial 4,566 575 3,895 4,470 1,848 4,283 184 Construction: Residential 140 140 — 140 — 76 9 Commercial — — — — — — — Total construction 140 140 — 140 — 76 9 Total $ 26,175 $ 18,078 $ 7,188 $ 25,266 $ 2,232 $ 24,626 $ 1,052 Impaired PNCI Loans – As of, or for the Twelve Months Ended, December 31, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 1,404 $ 1,359 $ — $ 1,359 $ — $ 1,041 $ 24 Commercial — — — — — 979 — Total mortgage loans on real estate 1,404 1,359 — 1,359 — 2,020 24 Consumer: Home equity lines of credit 1,216 591 603 1,194 316 1,240 48 Home equity loans 178 44 121 165 97 117 6 Other 250 — 250 250 54 186 11 Total consumer loans 1,644 635 974 1,609 467 1,543 65 Commercial — — — — — — — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total $ 3,048 $ 1,994 $ 974 $ 2,968 $ 467 $ 3,563 $ 89 Impaired Originated Loans – As of, or for the Nine Months Ended, September 30, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 3,489 $ 1,777 $ 1,644 $ 3,421 $ 167 $ 3,242 $ 90 Commercial 18,643 17,039 1,150 18,189 73 15,990 514 Total mortgage loans on real estate 22,132 18,816 2,794 21,610 240 19,232 604 Consumer: Home equity lines of credit 1,324 1,108 110 1,218 33 1,564 25 Home equity loans 2,091 1,470 199 1,669 13 1,376 32 Other 59 3 11 14 7 23 (25 ) Total consumer loans 3,474 2,581 320 2,901 53 2,963 32 Commercial 3,262 884 2,048 2,932 1,270 3,514 69 Construction: Residential 144 144 — 144 — 78 7 Commercial — — — — — — — Total construction 144 144 — 144 — 78 7 Total $ 29,012 $ 22,425 $ 5,162 $ 27,587 $ 1,563 $ 25,787 $ 712 Impaired PNCI Loans – As of, or for the Nine Months Ended, September 30, 2017 (in thousands) Unpaid Recorded Recorded Total recorded Related Average Interest income Mortgage loans on real estate: Residential 1-4 $ 1,634 $ 1,356 $ 250 $ 1,606 $ 73 $ 1,165 $ 24 Commercial 1,869 1,599 — 1,599 — 1,778 — Total mortgage loans on real estate 3,503 2,955 250 3,205 73 2,943 24 Consumer: Home equity lines of credit 1,020 394 607 1,001 328 1,143 28 Home equity loans 185 50 123 173 99 121 5 Other 253 — 253 253 71 187 8 Total consumer loans 1,458 444 983 1,427 498 1,451 41 Commercial 6 — — — 6 3 — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total $ 4,967 $ 3,399 $ 1,233 $ 4,632 $ 577 $ 4,397 $ 65
Troubled Debt Restructurings	The following tables show certain information regarding TDRs that occurred during the periods indicated: TDR Information for the Three Months Ended September 30, 2018 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 — $ — $ — $ — — $ — $ — Commercial 4 1,326 1,324 (308 ) — — — Total mortgage loans on real estate 4 1,326 1,324 (308 ) — — — Consumer: Home equity lines of credit — — — — 1 128 — Home equity loans 1 478 478 — — — — Other — — — — — — — Total consumer loans 1 478 478 — 1 128 — Commercial 2 203 203 — — — — Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total 7 $ 2,007 $ 2,005 $ (308 ) 1 $ 128 $ — TDR Information for the Nine Months Ended September 30, 2018 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 — $ — $ — $ — — $ — $ — Commercial 6 1,743 1,741 (262 ) 1 169 — Total mortgage loans on real estate 6 1,743 1,741 (262 ) 1 169 — Consumer: Home equity lines of credit 1 133 138 — 1 128 — Home equity loans 2 599 599 — — — — Other — — — — — — — Total consumer loans 3 732 737 — 1 128 — Commercial 4 619 623 (3 ) 4 340 (2 ) Construction: Residential — — — — — — — Commercial — — — — — — — Total construction — — — — — — — Total 13 $ 3,094 $ 3,101 $ (265 ) 6 $ 637 $ (2 ) The following tables show certain information regarding TDRs that occurred during the periods indicated: TDR Information for the Three Months Ended September 30, 2017 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 1 $ 939 $ 939 $ 169 1 $ 99 $ — Commercial 4 2,886 2,886 14 1 219 — Total mortgage loans on real estate 5 3,825 3,825 183 2 318 — Consumer: Home equity lines of credit — — — — — — — Home equity loans 1 252 252 — — — — Other — — — — — — — Total consumer loans 1 252 252 — — — — Commercial 8 1,109 1,109 28 — Construction: Residential 1 144 144 — — — — Commercial — — — — — — — Total construction 1 144 144 — — — — Total 15 $ 5,330 $ 5,330 $ 211 2 $ 318 $ — TDR Information for the Nine Months Ended September 30, 2017 (dollars in thousands) Number Pre-mod Post-mod Financial Number that Recorded Financial Mortgage loans on real estate: Residential 1-4 1 $ 939 $ 939 $ 169 2 $ 223 $ — Commercial 7 3,509 3,482 (111 ) 1 219 — Total mortgage loans on real estate 8 4,448 4,421 58 3 442 — Consumer: Home equity lines of credit 3 187 187 27 — — — Home equity loans 1 252 252 — — — — Other 1 14 14 11 — — — Total consumer loans 5 453 453 38 — — — Commercial 11 1,854 1,748 37 — Construction: Residential 1 144 144 — — — — Commercial — — — — — — — Total construction 1 144 144 — — — — Total 25 $ 6,899 $ 6,766 $ 133 3 $ 442 $ —

Foreclosed Assets (Tables)

Foreclosed Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Summary of Activity in Balance of Foreclosed Assets	A summary of the activity in the balance of foreclosed assets follows (in thousands): Nine months ended September 30, 2018 2017 Beginning balance, net $ 3,226 $ 3,986 Additions/transfers from loans 536 726 Dispositions/sales (1,841 ) (1,479 ) Valuation adjustments (89 ) (162 ) Ending balance, net $ 1,832 $ 3,071 Ending valuation allowance $ (143 ) $ (248 ) Ending number of foreclosed assets 11 11 Proceeds from sale of foreclosed assets $ 2,206 $ 1,787 Gain on sale of foreclosed assets $ 390 $ 308

Premises and Equipment (Tables)

Premises and Equipment (Tables)	9 Months Ended
	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Summary of Premises and Equipment	Premises and equipment were comprised of: September 30, December 31, 2018 2017 (In thousands) Land & land improvements $ 28,958 $ 9,959 Buildings 64,178 50,340 Furniture and equipment 44,271 35,939 137,407 96,238 Less: Accumulated depreciation (49,073 ) (40,644 ) 88,334 55,594 Construction in progress 956 2,148 Total premises and equipment $ 89,290 $ 57,742

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Goodwill Intangible	The following table summarizes the Company’s goodwill intangible as of the dates indicated: September 30, December 31, (in thousands) 2018 Additions Reductions 2017 Goodwill $ 220,972 156,661 — $ 64,311
Summary of Core Deposit Intangibles	The following table summarizes the Company’s core deposit intangibles (CDI) as of the dates indicated: September 30, Reductions/ December 31, (in thousands) 2018 Additions Amortization 2017 Core deposit intangibles $ 37,163 27,605 — $ 9,558 Accumulated amortization (6,452 ) — $ (2,068 ) (4,384 ) Core deposit intangibles, net $ 30,711 27,605 $ (2,068 ) $ 5,174
Remaining Estimated Core Deposit Intangible Amortization	The following table summarizes the Company’s remaining estimated core deposit intangible amortization at September 30, 2018 (in thousands): Estimated Core Deposit Years Ended Intangible Amortization 2018 $ 1,431 2019 5,723 2020 5,723 2021 5,465 2022 4,776 Thereafter 7,593

Other Assets (Tables)

Other Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Other Assets	Other assets were comprised of (in thousands): September 30, December 31, Deferred tax asset, net $ 31,963 $ 21,697 Investment in low income housing tax credit funds 23,572 16,854 Prepaid expense 3,420 4,111 Tax refund receivable 2,836 4,754 Capital trusts 1,712 1,706 Software 762 1,126 Life insurance proceeds receivable — 2,242 Miscellaneous other assets 6,332 2,561 Total other assets $ 70,597 $ 55,051

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2018
Banking and Thrift [Abstract]
Summary of Balances of Deposits	A summary of the balances of deposits follows (in thousands): September 30, December 31, Noninterest-bearing demand $ 1,710,505 $ 1,368,218 Interest-bearing demand 1,152,705 971,459 Savings 1,801,087 1,364,518 Time certificates, over $250,000 140,805 73,596 Other time certificates 288,015 231,340 Total deposits $ 5,093,117 $ 4,009,131

Other Liabilities (Tables)

Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Other Liabilities Disclosure [Abstract]
Components of Other Liabilities	Other liabilities were comprised of (in thousands): September 30, December 31, Pension liability $ 37,789 $ 28,472 Low income housing tax credit fund commitments 9,146 8,554 Deferred compensation 9,450 6,605 Accrued salaries and benefits expense 8,990 6,619 Joint beneficiary agreements 3,558 3,365 Loan escrow and servicing payable 2,821 1,958 Deferred revenue 1,978 1,228 Litigation contingency — 1,450 Miscellaneous other liabilities 8,345 8,171 Total other liabilities $ 82,077 $ 66,422

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Commitments under Non-Cancelable Operating Leases with Initial or Remaining Terms of One Year or More	At September 30, 2018, future minimum commitments under non-cancelable Operating Leases (in thousands) 2018 $ 1,179 2019 4,478 2020 3,774 2021 3,372 2022 2,549 Thereafter 4,097 Future minimum lease payments $ 19,449
Summary of Bank's Commitments and Contingent Liabilities	The following table presents a summary of the Bank’s commitments and contingent liabilities: (in thousands) September 30, December 31, Financial instruments whose amounts represent risk: Commitments to extend credit: Commercial loans $ 310,844 $ 257,220 Consumer loans 481,837 422,958 Real estate mortgage loans 149,003 66,267 Real estate construction loans 283,858 187,097 Standby letters of credit 11,277 13,075 Deposit account overdraft privilege 107,956 98,260

Stock Options and Other Equit_2

Stock Options and Other Equity-Based Incentive Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Activity	Stock option activity during the nine months ended September 30, 2018 is summarized in the following table: Number Option Price Weighted Outstanding at December 31, 2017 446,400 $ 12.63 to $23.21 $ 16.84 Options granted — — to — — Options exercised (27,400 ) $ 15.34 to $23.21 $ 17.33 Options forfeited (3,000 ) $ 23.21 to $23.21 $ 23.21 Outstanding at September 30, 2018 416,000 $ 12.63 to $23.21 $ 16.77
Summary of Options Outstanding	The following table shows the number, weighted-average exercise price, intrinsic value, and weighted average remaining contractual life of options exercisable, options not yet exercisable and total options outstanding as of September 30, 2018: Currently Currently Not Total Number of options 413,000 3,000 416,000 Weighted average exercise price $ 16.72 $ 23.21 $ 16.77 Intrinsic value (in thousands) $ 9,045 $ 46 $ 9,091 Weighted average remaining contractual term (yrs.) 3.2 6.0 3.2
Restricted Stock Unit (RSU) Activity	Restricted stock unit (RSU) activity is summarized in the following table for the dates indicated: Service Condition Vesting RSUs Market Plus Service Number Weighted Number Weighted Outstanding at December 31, 2017 68,457 52,829 RSUs granted 38,605 $ 39.08 16,939 $ 36.40 Additional market plus service condition RSUs vested — 8,506 RSUs added through dividend credits 806 — RSUs released through vesting (32,516 ) (25,512 ) RSUs forfeited/expired (4,744 ) (5,478 ) Outstanding at September 30, 2018 70,608 47,284

Noninterest Income and Expense

Noninterest Income and Expense (Tables)	9 Months Ended
	Sep. 30, 2018
Other Income and Expenses [Abstract]
Components of Other Noninterest Income	The following table summarizes the Company’s noninterest income for the periods indicated (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 ATM and interchange fees $ 4,590 $ 4,209 $ 13,335 $ 12,472 Service charges on deposit accounts 4,015 4,160 11,407 12,102 Other service fees 676 917 2,020 2,521 Mortgage banking service fees 499 514 1,527 1,561 Change in value of mortgage servicing rights (37 ) (325 ) 38 (795 ) Total service charges and fees 9,743 9,475 28,327 27,861 Commissions on sale of non-deposit 728 672 2,414 1,984 Increase in cash value of life insurance 732 732 1,996 2,043 Gain on sale of loans 539 606 1,831 2,293 Lease brokerage income 186 234 514 601 Gain on sale of foreclosed assets 2 37 390 308 Sale of customer checks 88 89 327 287 Gain on sale of investment securities 207 961 207 961 Loss on disposal of fixed assets (152 ) (33 ) (206 ) (61 ) Loss on marketable equity securities (22 ) — (92 ) — Other 135 157 942 1,266 Total other noninterest income 2,443 3,455 8,323 9,682 Total noninterest income $ 12,186 $ 12,930 $ 36,650 $ 37,543
Components of Noninterest Expense	The components of noninterest expense were as follows (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Base salaries, net of deferred loan origination costs $ 17,051 $ 13,600 $ 45,442 $ 40,647 Incentive compensation 3,223 2,609 7,834 6,980 Benefits and other compensation costs 5,549 4,724 15,652 14,693 Total salaries and benefits expense 25,823 20,933 68,928 62,320 Occupancy 3,173 2,799 8,574 8,196 Data processing and software 2,786 2,495 7,979 7,332 Merger and acquisition expense 4,150 — 5,227 — Equipment 1,750 1,816 4,938 5,344 ATM and POS network charges 1,195 1,425 3,858 3,353 Advertising 1,341 1,039 3,214 3,173 Professional fees 929 901 2,475 2,357 Telecommunications 819 716 2,201 2,027 Regulatory assessments and insurance 537 427 1,384 1,252 Intangible amortization 1,390 339 2,068 1,050 Postage 275 325 934 1,058 Courier service 278 235 769 752 Operational losses 217 301 763 1,166 Foreclosed assets expense 93 41 297 117 Provision for (reversal of) foreclosed asset losses (1 ) 134 89 162 Other miscellaneous expense 2,623 3,296 9,712 9,289 Total other noninterest expense 21,555 16,289 54,482 46,628 Total noninterest expense $ 47,378 $ 37,222 $ 123,410 $ 108,948

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Computation of Earnings Per Share	Earnings per share have been computed based on the following: Three months ended September 30, Nine months ended September 30, (in thousands) 2018 2017 2018 2017 Net income $ 16,170 $ 11,897 $ 45,109 $ 37,565 Average number of common shares outstanding 30,011 22,932 25,317 22,901 Effect of dilutive stock options and restricted stock 280 312 300 338 Average number of common shares outstanding used to calculate diluted earnings per share 30,291 23,244 25,617 23,239 Options excluded from diluted earnings per share because the effect of these options was antidilutive 10,000 — 10,000 —

Comprehensive Income (Tables)

Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss	The components of accumulated other comprehensive loss, included in shareholders’ equity, are as follows: September 30, December 31, (in thousands) 2018 2017 Net unrealized loss on available for sale securities $ (33,051 ) (3,409 ) Tax effect 9,771 1,433 Unrealized holding loss on available for sale securities, net of tax (23,280 ) (1,976 ) Unfunded status of the supplemental retirement plans (5,010 ) (5,352 ) Tax effect 1,481 2,250 Unfunded status of the supplemental retirement plans, net of tax (3,529 ) (3,102 ) Joint beneficiary agreement liability (150 ) (150 ) Tax effect — — Joint beneficiary agreement liability, net of tax (150 ) (150 ) Accumulated other comprehensive loss $ (26,959 ) $ (5,228 )
Components of Other Comprehensive Income (Loss) and Related Tax Effects	The components of other comprehensive income (loss) and related tax effects are as follows: Three months ended September 30, Nine months ended September 30, (in thousands) 2018 2017 2018 2017 Unrealized holding gains (losses) on available for sale securities before reclassifications $ (8,193 ) $ 674 $ (29,134 ) $ 6,372 Amounts reclassified out of accumulated other comprehensive income: Realized gains on debt securities (207 ) (961 ) (207 ) (961 ) Adoption ASU 2016-01 — — 62 — Adoption ASU 2018-02 — — (425 ) — Total amounts reclassified out of accumulated other comprehensive income (207 ) (961 ) (570 ) (961 ) Unrealized holding gains (losses) on available for sale securities after reclassifications (8,400 ) (287 ) (29,704 ) 5,411 Tax effect 2,483 121 8,763 (2,274 ) Unrealized holding gains (losses) on available for sale securities, net of tax (5,917 ) (166 ) (20,941 ) 3,137 Change in unfunded status of the supplemental retirement — — 668 — Amounts reclassified out of accumulated other comprehensive income: Amortization of prior service cost (13 ) (1 ) (40 ) (5 ) Amortization of actuarial losses 128 96 382 288 Adoption ASU 2018-02 — — (668 ) — Total amounts reclassified out of accumulated other comprehensive income 115 95 (326 ) 283 Change in unfunded status of the supplemental retirement plans after reclassifications 115 95 342 283 Tax effect (34 ) (40 ) (101 ) (119 ) Change in unfunded status of the supplemental retirement plans, net of tax 81 55 241 164 Total other comprehensive income (loss) $ (5,836 ) $ (111 ) $ (20,700 ) $ 3,301

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Recorded Amount of Assets and Liabilities Measured at Fair Value on Recurring Basis	The table below presents the recorded amount of assets and liabilities measured at fair value on a recurring basis (in thousands): Total Level 1 Level 2 Level 3 Fair value at September 30, 2018 Marketable equity securities $ 2,846 $ 2,846 $ — $ — Debt securities available for sale: Obligations of U.S. government agencies 638,876 — 638,876 — Obligations of states and political subdivisions 123,420 — 123,420 — Corporate bonds 4,431 — 4,431 — Asset backed securities 289,233 — 289,233 — Loans held for sale 3,824 — 3,824 — Mortgage servicing rights 7,122 — — 7,122 Total assets measured at fair value $ 1,069,752 $ 2,846 $ 1,059,784 $ 7,122 Total Level 1 Level 2 Level 3 Fair value at December 31, 2017 Marketable equity securities $ 2,938 $ 2,938 $ — $ — Debt securities available for sale: Obligations of U.S. government agencies 604,789 — 604,789 — Obligations of states and political subdivisions 123,156 — 123,156 — Loans held for sale 4,616 — 4,616 — Mortgage servicing rights 6,687 — — 6,687 Total assets measured at fair value $ 742,186 $ 2,938 $ 732,561 $ 6,687
Reconciliation of Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) on Recurring Basis	The following table provides a reconciliation of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) on a recurring basis during the time periods indicated. Had there been any transfer into or out of Level 3 during the time periods indicated, the amount included in the “Transfers into (out of) Level 3” column would represent the beginning balance of an item in the period (interim quarter) during which it was transferred (in thousands): Beginning Transfers Change Issuances Ending Three months ended September 30, 2018: Mortgage servicing rights $ 7,021 — $ (37 ) $ 138 $ 7,122 2017: Mortgage servicing rights $ 6,596 — $ (325 ) $ 148 $ 6,419 Beginning Transfers Change Issuances Ending Nine months ended September 30, 2018: Mortgage servicing rights $ 6,687 — $ 38 $ 397 $ 7,122 2017: Mortgage servicing rights $ 6,595 — $ (795 ) $ 619 $ 6,419
Quantitative Information about Recurring Level 3 Fair Value Measurements	The following table presents quantitative information about recurring Level 3 fair value measurements at September 30, 2018: Fair Value Valuation Unobservable Range, (in thousands) Technique Inputs Average Mortgage Servicing Rights $ 7,122 Discounted Constant 4.8%-33%, 7.3% Discount rate 12%, 12% The following table presents quantitative information about recurring Level 3 fair value measurements at December 31, 2017: Fair Value Valuation Unobservable Range, (in thousands) Technique Inputs Average Mortgage Servicing Rights $ 6,687 Discounted Constant 6.2%-22.0%, 8.9% Discount rate 13.0%-15.0%, 13.0%
Assets and Liabilities Measured at Fair Value on Nonrecurring Basis	The tables below present the recorded investment in assets and liabilities measured at fair value on a nonrecurring basis, as of the dates indicated (in thousands): Total Level 1 Level 2 Level 3 Total Gains Nine months ended September 30, 2018 Fair value: Impaired Originated & PNCI loans $ 445 — — $ 445 $ (808 ) Foreclosed assets 863 — — 863 (23 ) Total assets measured at fair value $ 1,308 — — $ 1,308 $ (831 ) Total Level 1 Level 2 Level 3 Total Gains Year ended December 31, 2017 Fair value: Impaired Originated & PNCI loans $ 2,767 — — $ 2,767 $ (1,452 ) Foreclosed assets 2,217 — — 2,217 (135 ) Total assets measured at fair value $ 4,984 — — $ 4,984 $ (1,587 ) Total Level 1 Level 2 Level 3 Total Gains Nine months ended September 30, 2017 Fair value: Impaired Originated & PNCI loans $ 1,026 — — $ 1,026 $ (892 ) Foreclosed assets 2,062 — — 2,062 (157 ) Total assets measured at fair value $ 3,088 — — $ 3,088 $ (1,049 )
Quantitative Information about Level 3 Fair Value Measurements for Financial Instruments Measured at Fair Value on Nonrecurring Basis	The following table presents quantitative information about Level 3 fair value measurements for financial instruments measured at fair value on a nonrecurring basis at September 30, 2018: Fair Value Valuation Range, (in thousands) Technique Unobservable Inputs Weighted Average September 30, 2018 Impaired Originated & PNCI loans $ 445 Sales comparison Adjustment for differences (55.8%) - 60%; (28%) Income approach Capitalization rate N/A Foreclosed assets (Residential real estate) $ 744 Sales comparison Adjustment for differences (47%) - 52%; 0.9% Foreclosed assets (Commercial real estate) $ 92 Sales comparison Adjustment for differences (65%) - 20%; (45%) Foreclosed assets (Land and construction) $ 27 Sales comparison Adjustment for differences Information not meaningful The following table presents quantitative information about Level 3 fair value measurements for financial instruments measured at fair value on a nonrecurring basis at December 31, 2017: Fair Value Valuation Range, (in thousands) Technique Unobservable Inputs Weighted Average December 31, 2017 Impaired Originated & PNCI loans $ 2,767 Sales comparison Adjustment for differences (74%) - 23%; (19.76%) Income approach Capitalization rate N/A Foreclosed assets (Land & construction) $ 1,341 Sales comparison Adjustment for differences (53%) - 283%; 167% Foreclosed assets (Residential real estate) $ 622 Sales comparison Adjustment for differences (47%) - 39%; (3.13%) Foreclosed assets (Commercial real estate) $ 254 Sales comparison Adjustment for differences (84%) - 19%; (84%)
Estimated Fair Values of Financial Instruments that are Reported at Amortized Cost in Consolidated Balance Sheets	The estimated fair values of financial instruments that are reported at amortized cost in the Company’s condensed consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows (in thousands): September 30, 2018 December 31, 2017 Carrying Fair Carrying Fair Amount Value Amount Value Financial assets: Level 1 inputs: Cash and due from banks $ 109,363 $ 109,363 $ 105,968 $ 105,968 Cash at Federal Reserve and other banks 117,180 117,180 99,460 99,460 Level 2 inputs: Securities held to maturity 459,897 446,287 514,844 518,165 Restricted equity securities 17,250 N/A 16,956 N/A Level 3 inputs: Loans, net 3,995,833 3,987,841 2,984,842 2,992,225 Financial liabilities: Level 2 inputs: Deposits 5,093,117 5,088,024 4,009,131 4,006,620 Other borrowings 282,831 282,831 122,166 122,166 Level 3 inputs: Junior subordinated debt 56,996 58,930 56,858 58,466 Contract Fair Contract Fair Amount Value Amount Value Off-balance Level 3 inputs: Commitments $ 1,225,542 $ 12,255 $ 933,542 $ 9,335 Standby letters of credit 11,277 113 13,075 131 Overdraft privilege commitments 107,956 1,080 98,260 983

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2018
Banking and Thrift [Abstract]
Actual and Required Capital Ratios of Bank	The following tables present actual and required capital ratios as of September 30, 2018 and December 31, 2017 for the Company and the Bank under Basel III Capital Rules. The minimum capital amounts presented include the minimum required capital levels as of September 30, 2018 and December 31, 2017 based on the then phased-in phased-in. Minimum Capital Minimum Capital Required to be Required – Basel III Required – Basel III Considered Well Actual Phase-in Fully Phased In Capitalized Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) As of September 30, 2018: Total Capital (to Risk Weighted Assets): Consolidated $ 664,197 13.90 % $ 471,956 9.875 % $ 501,826 10.50 % N/A N/A Tri Counties Bank $ 658,075 13.77 % $ 471,784 9.875 % $ 501,643 10.50 % $ 477,756 10.00 % Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 630,294 13.19 % $ 376,370 7.875 % $ 406,240 8.50 % N/A N/A Tri Counties Bank $ 624,172 13.06 % $ 376,233 7.875 % $ 406,092 8.50 % $ 382,205 8.00 % Common equity Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 575,010 12.03 % $ 304,680 6.375 % $ 334,551 7.00 % N/A N/A Tri Counties Bank $ 624,172 13.06 % $ 304,569 6.375 % $ 334,429 7.00 % $ 310,541 6.50 % Tier 1 Capital (to Average Assets): Consolidated $ 630,294 10.66 % $ 236,503 4.000 % $ 236,503 4.00 % N/A N/A Tri Counties Bank $ 624,172 10.56 % $ 236,496 4.000 % $ 236,496 4.00 % $ 295,620 5.00 % Minimum Capital Minimum Capital Required to be Required – Basel III Required – Basel III Considered Well Actual Phase-in Fully Phased In Capitalized Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) As of December 31, 2017: Total Capital (to Risk Weighted Assets): Consolidated $ 528,805 14.07 % $ 347,694 9.250 % $ 394,679 10.50 % N/A N/A Tri Counties Bank $ 525,384 13.98 % $ 347,535 9.250 % $ 394,499 10.50 % $ 375,713 10.00 % Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 495,318 13.18 % $ 272,517 7.250 % $ 319,502 8.50 % N/A N/A Tri Counties Bank $ 491,897 13.09 % $ 272,392 7.250 % $ 319,356 8.50 % $ 300,570 8.00 % Common equity Tier 1 Capital (to Risk Weighted Assets): Consolidated $ 440,643 11.72 % $ 216,134 5.750 % $ 263,120 7.00 % N/A N/A Tri Counties Bank $ 491,897 13.09 % $ 216,035 5.750 % $ 262,999 7.00 % $ 244,214 6.50 % Tier 1 Capital (to Average Assets): Consolidated $ 495,318 10.80 % $ 183,400 4.000 % $ 183,400 4.00 % N/A N/A Tri Counties Bank $ 491,897 10.73 % $ 183,394 4.000 % $ 183,394 4.00 % $ 229,243 5.00 %

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)OfficeTrustBranchBusiness	Jan. 01, 2018USD ($)
Significant Of Accounting Policies [Line Items]
Number of subsidiary business trusts | Trust	5
Number of loan production offices | Office	2
Company's investments in the trusts	$ 1,741,000
Tri Counties Bank [Member]
Significant Of Accounting Policies [Line Items]
Number of traditional operating branches | Branch	69
Number of in-store operating branches | Branch	9
California [Member]
Significant Of Accounting Policies [Line Items]
Number of counties | Business	29
ASU 2016-02 [Member] | Assets, Total [Member]
Significant Of Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 30,000,000
ASU 2016-02 [Member] | Liabilities, Total [Member]
Significant Of Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 30,000,000
ASU 2018-02 [Member] | Retained Earnings [Member]
Significant Of Accounting Policies [Line Items]
New accounting pronouncement or change in accounting principle cumulative effect of change on equity or net assets		$ 1,093,000
ASU 2018-02 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Significant Of Accounting Policies [Line Items]
New accounting pronouncement or change in accounting principle cumulative effect of change on equity or net assets		$ (1,093,000)

Business Combinations - Additio

Business Combinations - Additional Information (Detail)	Jul. 06, 2018USD ($)Branchesshares	Sep. 30, 2018USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Goodwill recognized		$ 220,972,000	$ 220,972,000		$ 64,311,000
PNCI [Member]
Business Acquisition [Line Items]
Receivables gross contractual amount		866,189,000	866,189,000
Receivables fair value		833,381,000	833,381,000
PCI [Member]
Business Acquisition [Line Items]
Receivables gross contractual amount		1,683,000	1,683,000
Receivables fair value		1,302,000	1,302,000
FNBB [Member]
Business Acquisition [Line Items]
Total consideration value	$ 291,132,000
Issue of common stock shares | shares	7,405,277
Amount paid in exchange for the outstanding options	$ 6,700,000
Number of branches added | Branches	12
Goodwill recognized	$ 156,661,000
Recognized intangible related to acquisition	27,605,000
FNBB [Member] | Core Deposit Intangibles [Member]
Business Acquisition [Line Items]
Recognized intangible related to acquisition	$ 27,605,000
Finite lived intangible asset estimated useful life	6 years 2 months 12 days
Acquisition related costs		$ 4,150,000	$ 5,227,000	$ 0

Business Combinations - Schedul

Business Combinations - Schedule of Fair Value of Consideration Transferred, Identifiable Net Assets Acquired and Resulting Goodwill (Detail) - USD ($) $ in Thousands	Jul. 06, 2018	Sep. 30, 2018	Dec. 31, 2017
Liabilities assumed:
Goodwill recognized		$ 220,972	$ 64,311
FNBB [Member]
Fair value of consideration transferred:
Fair value of shares issued	$ 284,437
Cash consideration	6,695
Total fair value of consideration transferred	291,132
Assets acquired:
Cash and cash equivalents	37,308
Securities available for sale	335,667
Restricted equity securities	7,723
Loans	834,683
Premises and equipment	30,522
Cash value of life insurance	16,817
Core deposit intangible	27,605
Other assets	16,214
Total assets acquired	1,306,539
Liabilities assumed:
Deposits	991,935
Other liabilities	15,133
Total liabilities assumed	1,172,068
Total net assets acquired	134,471
Goodwill recognized	156,661
FNBB [Member] | Federal Home Loan Bank of San Francisco [Member]
Liabilities assumed:
Short-term borrowings	$ 165,000

Business Combinations - Sched_2

Business Combinations - Schedule of Business Acquisition Pro-forma financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Summarized proforma income statement data:
Net interest income	$ 61,259	$ 57,329	$ 178,434	$ 168,363
Provision for (benefit from) loan losses	2,651	765	1,374	(1,728)
Noninterest income	12,288	13,902	38,517	40,537
Noninterest expense	(40,850)	(45,983)	(135,048)	(135,218)
Income before taxes	30,046	24,483	80,529	75,410
Income taxes	8,384	9,055	22,996	27,436
Net income	$ 21,662	$ 15,428	$ 57,533	$ 47,974
Basic earnings per share	$ 0.72	$ 0.51	$ 1.76	$ 1.58
Diluted earnings per share	$ 0.71	$ 0.50	$ 1.74	$ 1.56

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Values of Investments in Debt Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Amortized Cost	$ 1,089,011	$ 731,292
Debt Securities Available for Sale, Gross Unrealized Gains	516	2,583
Debt Securities Available for Sale, Gross Unrealized Losses	(33,567)	(5,930)
Debt Securities Available for Sale, Estimated Fair Value	1,055,960	727,945
Debt Securities Held to Maturity, Amortized Cost	459,897	514,844
Debt Securities Held to Maturity, Gross Unrealized Gains	146	5,247
Debt Securities Held to Maturity, Gross Unrealized Losses	(13,756)	(1,926)
Debt Securities Held to Maturity, Estimated Fair Value	446,287	518,165
Obligations of U.S. Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Amortized Cost	666,021	609,695
Debt Securities Available for Sale, Gross Unrealized Gains	163	695
Debt Securities Available for Sale, Gross Unrealized Losses	(27,308)	(5,601)
Debt Securities Available for Sale, Estimated Fair Value	638,876	604,789
Debt Securities Held to Maturity, Amortized Cost	445,309	500,271
Debt Securities Held to Maturity, Gross Unrealized Gains	88	5,101
Debt Securities Held to Maturity, Gross Unrealized Losses	(13,361)	(1,889)
Debt Securities Held to Maturity, Estimated Fair Value	432,036	503,483
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Amortized Cost	129,072	121,597
Debt Securities Available for Sale, Gross Unrealized Gains	107	1,888
Debt Securities Available for Sale, Gross Unrealized Losses	(5,759)	(329)
Debt Securities Available for Sale, Estimated Fair Value	123,420	123,156
Debt Securities Held to Maturity, Amortized Cost	14,588	14,573
Debt Securities Held to Maturity, Gross Unrealized Gains	58	146
Debt Securities Held to Maturity, Gross Unrealized Losses	(395)	(37)
Debt Securities Held to Maturity, Estimated Fair Value	14,251	$ 14,682
Corporate Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Amortized Cost	4,368
Debt Securities Available for Sale, Gross Unrealized Gains	65
Debt Securities Available for Sale, Gross Unrealized Losses	(2)
Debt Securities Available for Sale, Estimated Fair Value	4,431
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Amortized Cost	289,550
Debt Securities Available for Sale, Gross Unrealized Gains	181
Debt Securities Available for Sale, Gross Unrealized Losses	(498)
Debt Securities Available for Sale, Estimated Fair Value	$ 289,233

Investment Securities - Additio

Investment Securities - Additional Information (Detail)	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)Investmentsecurities	Sep. 30, 2017USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Sep. 30, 2018USD ($)Investmentsecurities	Dec. 31, 2017USD ($)
Investment Securities [Line Items]
Proceeds from sales of available for sale debt securities	$ 293,279,000	$ 25,757,000
Gross realized gains	207,000	$ 961,000
Investment securities sold			$ 0	$ 0
Securities Pledged As Collateral	548,123,000				$ 548,123,000	$ 285,596,000
Residential real estate mortgage-backed securities	$ 1,111,330,000				$ 1,111,330,000
Life of mortgage-backed securities					6 years 1 month 6 days
Obligations of U.S. Government Agencies [Member]
Investment Securities [Line Items]
Available for sale securities in unrealized loss position | Investmentsecurities	171				171
Percentage of aggregate depreciation in unrealized losses	3.70%				3.70%
Obligations of States and Political Subdivisions [Member]
Investment Securities [Line Items]
Available for sale securities in unrealized loss position | Investmentsecurities	132				132
Percentage of aggregate depreciation in unrealized losses	5.00%				5.00%
Corporate Bonds [Member]
Investment Securities [Line Items]
Available for sale securities in unrealized loss position | Investmentsecurities	1				1
Percentage of aggregate depreciation in unrealized losses	0.10%				0.10%
Asset-backed Securities [Member]
Investment Securities [Line Items]
Available for sale securities in unrealized loss position | Investmentsecurities	6				6
Percentage of aggregate depreciation in unrealized losses	0.60%				0.60%

Investment Securities - Amort_2

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Due in one year, Amortized Cost	$ 2,435
Due after one year through five years, Amortized Cost	12,486
Due after five years through ten years, Amortized Cost	17,764
Due after ten years, Amortized Cost	1,056,326
Totals, Amortized Cost	1,089,011
Due in one year, Estimated Fair Value	2,434
Due after one year through five years, Estimated Fair Value	12,501
Due after five years through ten years, Estimated Fair Value	17,740
Due after ten years, Estimated Fair Value	1,023,285
Totals, Estimated Fair Value	1,055,960
Due in one year, Amortized Cost, Held to Maturity	0
Due after one year through five years, Amortized Cost, Held to Maturity	1,231
Due after five years through ten years, Amortized Cost, Held to Maturity	25,955
Due after ten years, Amortized Cost, Held to Maturity	432,711
Totals, Amortized Cost, Held to Maturity	459,897	$ 514,844
Due in one year, Estimated Fair Value, Held to Maturity	0
Due after one year through five years, Estimated Fair Value, Held to Maturity	1,240
Due after five years through ten years, Estimated Fair Value, Held to Maturity	25,210
Due after ten years, Estimated Fair Value, Held to Maturity	419,837
Estimated Fair Value, Held to Maturity	$ 446,287	$ 518,165

Investment Securities - Gross U

Investment Securities - Gross Unrealized Losses on Debt Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Less than 12 months, Fair Value	$ 491,552	$ 289,271
Debt Securities Available for Sale, Less than 12 months, Unrealized Loss	(14,998)	(2,211)
Debt Securities Available for Sale, 12 months or more, Fair Value	329,358	183,423
Debt Securities Available for Sale, 12 months or more, Unrealized Loss	(18,569)	(3,719)
Debt Securities Available for Sale, Fair Value	820,910	472,694
Debt Securities Available for Sale, Unrealized Loss	(33,567)	(5,930)
Debt Securities Held to Maturity, Less than 12 months, Fair Value	316,403	94,505
Debt Securities Held to Maturity, Less than 12 months, Unrealized Loss	(7,923)	(574)
Debt Securities Held to Maturity, 12 months or more, Fair Value	112,388	98,004
Debt Securities Held to Maturity, 12 months or more, Unrealized Loss	(5,833)	(1,352)
Debt Securities Held to Maturity, Fair Value	428,791	192,509
Debt Securities Held to Maturity, Unrealized Loss	(13,756)	(1,926)
Obligations of U.S. Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Less than 12 months, Fair Value	323,972	284,367
Debt Securities Available for Sale, Less than 12 months, Unrealized Loss	(10,839)	(2,176)
Debt Securities Available for Sale, 12 months or more, Fair Value	311,035	166,338
Debt Securities Available for Sale, 12 months or more, Unrealized Loss	(16,469)	(3,425)
Debt Securities Available for Sale, Fair Value	635,007	450,705
Debt Securities Available for Sale, Unrealized Loss	(27,308)	(5,601)
Debt Securities Held to Maturity, Less than 12 months, Fair Value	307,432	93,017
Debt Securities Held to Maturity, Less than 12 months, Unrealized Loss	(7,693)	(567)
Debt Securities Held to Maturity, 12 months or more, Fair Value	109,312	95,367
Debt Securities Held to Maturity, 12 months or more, Unrealized Loss	(5,668)	(1,322)
Debt Securities Held to Maturity, Fair Value	416,744	188,384
Debt Securities Held to Maturity, Unrealized Loss	(13,361)	(1,889)
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Less than 12 months, Fair Value	85,668	4,904
Debt Securities Available for Sale, Less than 12 months, Unrealized Loss	(3,659)	(35)
Debt Securities Available for Sale, 12 months or more, Fair Value	18,323	17,085
Debt Securities Available for Sale, 12 months or more, Unrealized Loss	(2,100)	(294)
Debt Securities Available for Sale, Fair Value	103,991	21,989
Debt Securities Available for Sale, Unrealized Loss	(5,759)	(329)
Debt Securities Held to Maturity, Less than 12 months, Fair Value	8,971	1,488
Debt Securities Held to Maturity, Less than 12 months, Unrealized Loss	(230)	(7)
Debt Securities Held to Maturity, 12 months or more, Fair Value	3,076	2,637
Debt Securities Held to Maturity, 12 months or more, Unrealized Loss	(165)	(30)
Debt Securities Held to Maturity, Fair Value	12,047	4,125
Debt Securities Held to Maturity, Unrealized Loss	(395)	$ (37)
Corporate Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Less than 12 months, Fair Value	1,969
Debt Securities Available for Sale, Less than 12 months, Unrealized Loss	(2)
Debt Securities Available for Sale, Fair Value	1,969
Debt Securities Available for Sale, Unrealized Loss	(2)
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities Available for Sale, Less than 12 months, Fair Value	79,943
Debt Securities Available for Sale, Less than 12 months, Unrealized Loss	(498)
Debt Securities Available for Sale, Fair Value	79,943
Debt Securities Available for Sale, Unrealized Loss	$ (498)

Loans - Summary of Loan Balance

Loans - Summary of Loan Balances (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Total principal balance of loans owed, net of charge-offs	$ 4,082,558		$ 3,038,472
Unamortized net deferred loan fees	(10,190)		(8,651)
Discounts to principal balance of loans owed, net of charge-offs	(44,932)		(14,656)
Total loans, net of unamortized deferred loan fees and discounts	4,027,436		3,015,165	$ 2,931,613
Allowance for loan losses	(31,603)	$ (29,524)	(30,323)	(28,747)	$ (28,143)	$ (32,503)
Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	3,132,202		2,300,322	2,194,874
Allowance for loan losses	(15,279)	(13,598)	(13,758)	(13,588)	(12,614)	(14,265)
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	421,285		356,874	361,320
Allowance for loan losses	(7,514)	(7,137)	(8,227)	(8,302)	(9,155)	(10,310)
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	289,647		220,412	227,479
Allowance for loan losses	(6,224)	(6,378)	(6,512)	(4,802)	(4,729)	(5,831)
Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	184,302		137,557	147,940
Allowance for loan losses	(2,586)	(2,411)	(1,826)	(2,055)	(1,645)	(2,097)
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	524,414		385,426	391,072
Allowance for loan losses	(2,400)	(1,991)	(2,317)	(2,218)	(2,495)	(2,748)
Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	40,693		43,031	45,033
Allowance for loan losses	(1,593)	(1,532)	(1,841)	(1,991)	(2,354)	(2,644)
Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	49,456		25,155	26,781
Allowance for loan losses	(700)	(557)	(586)	(590)	(645)	(622)
Commercial [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,607,788		1,914,896	1,803,802
Allowance for loan losses	(12,879)	(11,607)	(11,441)	(11,370)	(10,119)	(11,517)
Commercial [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	69,728		69,627	72,820
Allowance for loan losses	(960)	(977)	(642)	(625)	(466)	(680)
Home Equity Lines of Credit [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	331,136		288,688	289,506
Allowance for loan losses	(5,221)	(5,048)	(5,800)	(5,721)	(6,156)	(7,044)
Residential [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	114,574		67,930	75,120
Allowance for loan losses	(1,626)	$ (1,434)	(1,184)	$ (1,430)	$ (1,179)	$ (1,417)
Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total principal balance of loans owed, net of charge-offs	2,940,897		2,699,053
Unamortized net deferred loan fees	(10,190)		(8,651)
Total loans, net of unamortized deferred loan fees and discounts	2,930,707		2,690,402
Allowance for loan losses	(30,927)		(29,122)
Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,204,119		2,011,032
Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	346,806		332,649
Originated [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	234,741		209,437
Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	145,041		137,284
Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	340,515		320,522
Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	35,556		39,848
Originated [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	26,294		22,859
Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,863,604		1,690,510
Originated [Member] | Commercial [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	63,508		69,364
Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	284,956		269,942
Originated [Member] | Residential [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	81,533		67,920
PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total principal balance of loans owed, net of charge-offs	1,120,654		316,238
Discounts to principal balance of loans owed, net of charge-offs	(37,723)		(7,035)
Total loans, net of unamortized deferred loan fees and discounts	1,082,931		309,203
Allowance for loan losses	(566)		(929)
PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	918,500		279,342
PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	72,691		21,197
PNCI [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	52,479		8,391
PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	39,261		273
PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	182,201		63,519
PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	4,690		2,698
PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	23,120		2,251
PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	736,299		215,823
PNCI [Member] | Commercial [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	6,220		263
PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	44,881		16,248
PNCI [Member] | Residential [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	33,041		10
PCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total principal balance of loans owed, net of charge-offs	21,007		23,181
Discounts to principal balance of loans owed, net of charge-offs	(7,209)		(7,621)
Total loans, net of unamortized deferred loan fees and discounts	13,798		15,560
Allowance for loan losses	(110)		(272)
PCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	9,583		9,948
PCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,788		3,028
PCI [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,427		2,584
PCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,698		1,385
PCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	447		485
PCI [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	42		45
PCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	7,885		8,563
PCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	$ 1,299		$ 2,498

Loans - Change in Accretable Yi

Loans - Change in Accretable Yield for PCI (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Change in accretable yield:
Balance at beginning of period	$ 3,996	$ 7,956	$ 4,262	$ 10,348
Accretion to interest income	(253)	(594)	(769)	(2,554)
Reclassification (to) from nonaccretable difference	(47)	(2,893)	203	(3,325)
Balance at end of period	$ 3,696	$ 4,469	$ 3,696	$ 4,469

Allowance for Loan Losses - Sum

Allowance for Loan Losses - Summary of Activity in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	$ 29,524	$ 28,143	$ 30,323	$ 32,503	$ 32,503
Charge-offs	(1,142)	(861)	(1,940)	(3,782)	(4,410)
Recoveries	570	700	1,443	1,614	2,141
Provision (benefit)	2,651	765	1,777	(1,588)	89
Ending Balance	31,603	28,747	31,603	28,747	30,323
Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	13,598	12,614	13,758	14,265	14,265
Charge-offs	(25)	(80)	(92)	(230)	(246)
Recoveries	15	238	51	365	397
Provision (benefit)	1,691	816	1,562	(812)	(658)
Ending Balance	15,279	13,588	15,279	13,588	13,758
Mortgage Loans on Real Estate [Member] | Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	11,607	10,119	11,441	11,517	11,517
Charge-offs		(20)	(15)	(170)	(186)
Recoveries	15	238	51	365	397
Provision (benefit)	1,257	1,033	1,402	(342)	(287)
Ending Balance	12,879	11,370	12,879	11,370	11,441
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	7,137	9,155	8,227	10,310	10,310
Charge-offs	(424)	(457)	(896)	(1,260)	(1,616)
Recoveries	353	401	1,061	933	1,315
Provision (benefit)	448	(797)	(878)	(1,681)	(1,782)
Ending Balance	7,514	8,302	7,514	8,302	8,227
Consumer [Member] | Home Equity Lines of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	5,048	6,156	5,800	7,044	7,044
Charge-offs	(172)	(14)	(276)	(98)	(98)
Recoveries	151	189	677	487	698
Provision (benefit)	194	(610)	(980)	(1,712)	(1,844)
Ending Balance	5,221	5,721	5,221	5,721	5,800
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	6,378	4,729	6,512	5,831	5,831
Charge-offs	(693)	(291)	(952)	(1,188)	(1,444)
Recoveries	202	61	331	315	428
Provision (benefit)	337	303	333	(156)	1,697
Ending Balance	6,224	4,802	6,224	4,802	6,512
Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	2,411	1,645	1,826	2,097	2,097
Charge-offs		(33)		(1,104)	(1,104)
Recoveries				1	1
Provision (benefit)	175	443	760	1,061	832
Ending Balance	2,586	2,055	2,586	2,055	1,826
Construction [Member] | Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	977	466	642	680	680
Recoveries				1	1
Provision (benefit)	(17)	159	318	(56)	(39)
Ending Balance	960	625	960	625	642
Construction [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	1,434	1,179	1,184	1,417	1,417
Charge-offs		(33)		(1,104)	(1,104)
Provision (benefit)	192	284	442	1,117	871
Ending Balance	1,626	1,430	1,626	1,430	1,184
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	1,991	2,495	2,317	2,748	2,748
Charge-offs	(25)	(60)	(77)	(60)	(60)
Provision (benefit)	434	(217)	160	(470)	(371)
Ending Balance	2,400	2,218	2,400	2,218	2,317
Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	1,532	2,354	1,841	2,644	2,644
Charge-offs	(23)	(94)	(23)	(331)	(332)
Recoveries	139	121	176	146	242
Provision (benefit)	(55)	(390)	(401)	(468)	(713)
Ending Balance	1,593	1,991	1,593	1,991	1,841
Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Beginning Balance	557	645	586	622	622
Charge-offs	(229)	(349)	(597)	(831)	(1,186)
Recoveries	63	91	208	300	375
Provision (benefit)	309	203	503	499	775
Ending Balance	$ 700	$ 590	$ 700	$ 590	$ 586

Allowance for Loan Losses - S_2

Allowance for Loan Losses - Summary of Activity in Allowance for Loan Losses, Net of Unearned Fees for Periods Indicated (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	$ 2,628		$ 2,699	$ 2,140
Allowance for Loan Losses, Loans pooled for evaluation	28,865		27,352	26,320
Total allowance for loan losses	31,603	$ 29,524	30,323	28,747	$ 28,143	$ 32,503
Loans, Net of Unearned fees , Individually evaluated for impairment	27,494		28,234	32,225
Loans, Net of Unearned fees , Loans pooled for evaluation	3,986,144		2,971,371	2,883,384
Total loans, net of unamortized deferred loan fees and discounts	4,027,436		3,015,165	2,931,613
Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	325		260	313
Allowance for Loan Losses, Loans pooled for evaluation	14,865		13,283	13,000
Total allowance for loan losses	15,279	13,598	13,758	13,588	12,614	14,265
Loans, Net of Unearned fees , Individually evaluated for impairment	18,025		19,209	24,815
Loans, Net of Unearned fees , Loans pooled for evaluation	3,104,594		2,271,165	2,160,483
Total loans, net of unamortized deferred loan fees and discounts	3,132,202		2,300,322	2,194,874
Mortgage Loans on Real Estate [Member] | Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	268		30	73
Allowance for Loan Losses, Loans pooled for evaluation	12,552		11,351	11,022
Total allowance for loan losses	12,879	11,607	11,441	11,370	10,119	11,517
Loans, Net of Unearned fees , Individually evaluated for impairment	13,244		13,911	19,788
Loans, Net of Unearned fees , Loans pooled for evaluation	2,586,659		1,892,422	1,775,843
Total loans, net of unamortized deferred loan fees and discounts	2,607,788		1,914,896	1,803,802
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	446		591	551
Allowance for Loan Losses, Loans pooled for evaluation	7,061		7,619	7,739
Total allowance for loan losses	7,514	7,137	8,227	8,302	9,155	10,310
Loans, Net of Unearned fees , Individually evaluated for impairment	4,837		4,415	4,328
Loans, Net of Unearned fees , Loans pooled for evaluation	414,660		349,431	353,259
Total loans, net of unamortized deferred loan fees and discounts	421,285		356,874	361,320
Consumer [Member] | Home Equity Lines of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	168		427	363
Allowance for Loan Losses, Loans pooled for evaluation	5,046		5,356	5,346
Total allowance for loan losses	5,221	5,048	5,800	5,721	6,156	7,044
Loans, Net of Unearned fees , Individually evaluated for impairment	2,188		2,688	2,219
Loans, Net of Unearned fees , Loans pooled for evaluation	327,649		283,502	284,335
Total loans, net of unamortized deferred loan fees and discounts	331,136		288,688	289,506
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	1,857		1,848	1,276
Allowance for Loan Losses, Loans pooled for evaluation	4,353		4,624	3,526
Total allowance for loan losses	6,224	6,378	6,512	4,802	4,729	5,831
Loans, Net of Unearned fees , Individually evaluated for impairment	4,632		4,470	2,938
Loans, Net of Unearned fees , Loans pooled for evaluation	282,588		213,358	221,846
Total loans, net of unamortized deferred loan fees and discounts	289,647		220,412	227,479
Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans pooled for evaluation	2,586		1,826	2,055
Total allowance for loan losses	2,586	2,411	1,826	2,055	1,645	2,097
Loans, Net of Unearned fees , Individually evaluated for impairment			140	144
Loans, Net of Unearned fees , Loans pooled for evaluation	184,302		137,417	147,796
Total loans, net of unamortized deferred loan fees and discounts	184,302		137,557	147,940
Construction [Member] | Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans pooled for evaluation	960		642	625
Total allowance for loan losses	960	977	642	625	466	680
Loans, Net of Unearned fees , Loans pooled for evaluation	69,728		69,627	72,820
Total loans, net of unamortized deferred loan fees and discounts	69,728		69,627	72,820
Construction [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans pooled for evaluation	1,626		1,184	1,430
Total allowance for loan losses	1,626	1,434	1,184	1,430	1,179	1,417
Loans, Net of Unearned fees , Individually evaluated for impairment			140	144
Loans, Net of Unearned fees , Loans pooled for evaluation	114,574		67,790	74,976
Total loans, net of unamortized deferred loan fees and discounts	114,574		67,930	75,120
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	57		230	240
Allowance for Loan Losses, Loans pooled for evaluation	2,313		1,932	1,978
Total allowance for loan losses	2,400	1,991	2,317	2,218	2,495	2,748
Loans, Net of Unearned fees , Individually evaluated for impairment	4,781		5,298	5,027
Loans, Net of Unearned fees , Loans pooled for evaluation	517,935		378,743	384,640
Total loans, net of unamortized deferred loan fees and discounts	524,414		385,426	391,072
Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	175		107	111
Allowance for Loan Losses, Loans pooled for evaluation	1,418		1,734	1,880
Total allowance for loan losses	1,593	1,532	1,841	1,991	2,354	2,644
Loans, Net of Unearned fees , Individually evaluated for impairment	2,406		1,470	1,842
Loans, Net of Unearned fees , Loans pooled for evaluation	37,840		41,076	42,454
Total loans, net of unamortized deferred loan fees and discounts	40,693		43,031	45,033
Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Individually evaluated for impairment	103		57	77
Allowance for Loan Losses, Loans pooled for evaluation	597		529	513
Total allowance for loan losses	700	$ 557	586	590	$ 645	$ 622
Loans, Net of Unearned fees , Individually evaluated for impairment	243		257	267
Loans, Net of Unearned fees , Loans pooled for evaluation	49,171		24,853	26,470
Total loans, net of unamortized deferred loan fees and discounts	49,456		25,155	26,781
Financial Asset Acquired with Credit Deterioration [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	110		272	287
Total loans, net of unamortized deferred loan fees and discounts	13,798		15,560	16,004
Financial Asset Acquired with Credit Deterioration [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	89		215	275
Total loans, net of unamortized deferred loan fees and discounts	9,583		9,948	9,576
Financial Asset Acquired with Credit Deterioration [Member] | Mortgage Loans on Real Estate [Member] | Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	59		60	275
Total loans, net of unamortized deferred loan fees and discounts	7,885		8,563	8,171
Financial Asset Acquired with Credit Deterioration [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	7		17	12
Total loans, net of unamortized deferred loan fees and discounts	1,788		3,028	3,733
Financial Asset Acquired with Credit Deterioration [Member] | Consumer [Member] | Home Equity Lines of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	7		17	12
Total loans, net of unamortized deferred loan fees and discounts	1,299		2,498	2,952
Financial Asset Acquired with Credit Deterioration [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	14		40
Total loans, net of unamortized deferred loan fees and discounts	2,427		2,584	2,695
Financial Asset Acquired with Credit Deterioration [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Allowance for Loan Losses, Loans acquired with deteriorated credit quality	30		155
Total loans, net of unamortized deferred loan fees and discounts	1,698		1,385	1,405
Financial Asset Acquired with Credit Deterioration [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	447		485	737
Financial Asset Acquired with Credit Deterioration [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	$ 42		$ 45	$ 44

Allowance for Loan Losses - Sch

Allowance for Loan Losses - Schedule Credit Quality Indicators (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	$ 4,027,436	$ 3,015,165	$ 2,931,613
Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	3,132,202	2,300,322	2,194,874
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	421,285	356,874	361,320
Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	289,647	220,412	227,479
Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	184,302	137,557	147,940
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	524,414	385,426	391,072
Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	40,693	43,031	45,033
Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	49,456	25,155	26,781
Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,930,707	2,690,402
Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,204,119	2,011,032
Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	346,806	332,649
Originated [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	234,741	209,437
Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	145,041	137,284
Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	340,515	320,522
Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	35,556	39,848
Originated [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	26,294	22,859
PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,082,931	309,203
PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	918,500	279,342
PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	72,691	21,197
PNCI [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	52,479	8,391
PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	39,261	273
PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	182,201	63,519
PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	4,690	2,698
PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	23,120	2,251
Commercial [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,607,788	1,914,896	1,803,802
Commercial [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	69,728	69,627	72,820
Commercial [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,863,604	1,690,510
Commercial [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	63,508	69,364
Commercial [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	736,299	215,823
Commercial [Member] | PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	6,220	263
Home Equity Lines of Credit [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	331,136	288,688	289,506
Home Equity Lines of Credit [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	284,956	269,942
Home Equity Lines of Credit [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	44,881	16,248
Residential [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	114,574	67,930	$ 75,120
Residential [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	81,533	67,920
Residential [Member] | PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	33,041	10
Pass [Member] | Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,860,727	2,617,171
Pass [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,156,897	1,964,453
Pass [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	339,607	325,205
Pass [Member] | Originated [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	220,328	195,208
Pass [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	143,895	132,305
Pass [Member] | Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	334,902	315,120
Pass [Member] | Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	32,242	37,428
Pass [Member] | Originated [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	25,885	22,432
Pass [Member] | PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,070,749	293,331
Pass [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	908,895	265,162
Pass [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	70,960	19,506
Pass [Member] | PNCI [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	51,633	8,390
Pass [Member] | PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	39,261	273
Pass [Member] | PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	179,634	61,411
Pass [Member] | PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	4,471	2,433
Pass [Member] | PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	23,083	2,207
Pass [Member] | Commercial [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,821,995	1,649,333
Pass [Member] | Commercial [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	62,660	64,492
Pass [Member] | Commercial [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	729,261	203,751
Pass [Member] | Commercial [Member] | PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	6,220	263
Pass [Member] | Home Equity Lines of Credit [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	281,480	265,345
Pass [Member] | Home Equity Lines of Credit [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	43,406	14,866
Pass [Member] | Residential [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	81,235	67,813
Pass [Member] | Residential [Member] | PNCI [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	33,041	10
Special Mention [Member] | Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	44,346	38,662
Special Mention [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	30,437	20,668
Special Mention [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	3,087	3,630
Special Mention [Member] | Originated [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	9,942	9,492
Special Mention [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	880	4,872
Special Mention [Member] | Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,690	2,234
Special Mention [Member] | Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,006	800
Special Mention [Member] | Originated [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	334	272
Special Mention [Member] | PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	6,066	12,408
Special Mention [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	4,358	11,731
Special Mention [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	974	676
Special Mention [Member] | PNCI [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	734	1
Special Mention [Member] | PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	880	218
Special Mention [Member] | PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	116	188
Special Mention [Member] | PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	32	38
Special Mention [Member] | Commercial [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	28,747	18,434
Special Mention [Member] | Commercial [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	848	4,872
Special Mention [Member] | Commercial [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	3,478	11,513
Special Mention [Member] | Home Equity Lines of Credit [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,747	2,558
Special Mention [Member] | Home Equity Lines of Credit [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	826	450
Special Mention [Member] | Residential [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	32
Substandard [Member] | Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	25,634	34,569
Substandard [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	16,785	25,911
Substandard [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	4,112	3,814
Substandard [Member] | Originated [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	4,471	4,737
Substandard [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	266	107
Substandard [Member] | Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	3,923	3,168
Substandard [Member] | Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	2,308	1,620
Substandard [Member] | Originated [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	75	155
Substandard [Member] | PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	6,116	3,464
Substandard [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	5,247	2,449
Substandard [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	757	1,015
Substandard [Member] | PNCI [Member] | Commercial Portfolio Segment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	112
Substandard [Member] | PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,687	1,890
Substandard [Member] | PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	103	77
Substandard [Member] | PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	5	6
Substandard [Member] | Commercial [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	12,862	22,743
Substandard [Member] | Commercial [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	3,560	559
Substandard [Member] | Home Equity Lines of Credit [Member] | Originated [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	1,729	2,039
Substandard [Member] | Home Equity Lines of Credit [Member] | PNCI [Member] | Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	649	932
Substandard [Member] | Residential [Member] | Originated [Member] | Construction [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total loans, net of unamortized deferred loan fees and discounts	$ 266	$ 107

Allowance for Loan Losses - Ana

Allowance for Loan Losses - Analysis of Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 4,027,436	$ 3,015,165	$ 2,931,613
Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	3,132,202	2,300,322	2,194,874
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	421,285	356,874	361,320
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	289,647	220,412	227,479
Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	184,302	137,557	147,940
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	524,414	385,426	391,072
Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	40,693	43,031	45,033
Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	49,456	25,155	26,781
Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	2,607,788	1,914,896	1,803,802
Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	69,728	69,627	72,820
Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	331,136	288,688	289,506
Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	114,574	67,930	$ 75,120
Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	8,645	8,927
Current	2,922,062	2,681,475
Total	2,930,707	2,690,402
Originated [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,528	3,638
Current	2,201,591	2,007,394
Total	2,204,119	2,011,032
Originated [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	3,176	2,034
Current	343,630	330,615
Total	346,806	332,649
Originated [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,453	3,221
Current	232,288	206,216
Total	234,741	209,437
Originated [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	488	34
Current	144,553	137,250
Total	145,041	137,284
Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,762	2,493
Current	338,753	318,029
Total	340,515	320,522
Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,231	991
Current	34,325	38,857
Total	35,556	39,848
Originated [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	286	95
Current	26,008	22,764
Total	26,294	22,859
Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	766	1,145
Current	1,862,838	1,689,365
Total	1,863,604	1,690,510
Originated [Member] | Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	63,508	69,364
Total	63,508	69,364
Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,659	948
Current	283,297	268,994
Total	284,956	269,942
Originated [Member] | Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	488	34
Current	81,045	67,886
Total	81,533	67,920
PNCI [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	4,573	2,682
Current	1,078,358	306,521
Total	1,082,931	309,203
> 90 Days and Still Accruing	1,048	281
PNCI [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,519	1,764
Current	915,981	277,578
Total	918,500	279,342
> 90 Days and Still Accruing	949	81
PNCI [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,552	918
Current	71,139	20,279
Total	72,691	21,197
> 90 Days and Still Accruing	99	200
PNCI [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	502
Current	51,977	8,391
Total	52,479	8,391
PNCI [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	39,261	273
Total	39,261	273
PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	560	1,694
Current	181,641	61,825
Total	182,201	63,519
> 90 Days and Still Accruing		81
PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	278	30
Current	4,412	2,668
Total	4,690	2,698
PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	242	32
Current	22,878	2,219
Total	23,120	2,251
PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,959	70
Current	734,340	215,753
Total	736,299	215,823
> 90 Days and Still Accruing	949
PNCI [Member] | Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	6,220	263
Total	6,220	263
PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,032	856
Current	43,849	15,392
Total	44,881	16,248
> 90 Days and Still Accruing	99	200
PNCI [Member] | Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	33,041	10
Total	33,041	10
30-59 Days [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	4,511	3,983
30-59 Days [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	774	1,898
30-59 Days [Member] | Originated [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,239	1,095
30-59 Days [Member] | Originated [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,010	956
30-59 Days [Member] | Originated [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	488	34
30-59 Days [Member] | Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	275	1,740
30-59 Days [Member] | Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	527	511
30-59 Days [Member] | Originated [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	262	56
30-59 Days [Member] | Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	499	158
30-59 Days [Member] | Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,450	528
30-59 Days [Member] | Originated [Member] | Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	488	34
30-59 Days [Member] | PNCI [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,139	1,899
30-59 Days [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	992	1,565
30-59 Days [Member] | PNCI [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,117	334
30-59 Days [Member] | PNCI [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	30
30-59 Days [Member] | PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due		1,495
30-59 Days [Member] | PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	262	30
30-59 Days [Member] | PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	242	6
30-59 Days [Member] | PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	992	70
30-59 Days [Member] | PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	613	298
60-89 Days [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,447	2,426
60-89 Days [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	899	1,497
60-89 Days [Member] | Originated [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	414	191
60-89 Days [Member] | Originated [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	134	738
60-89 Days [Member] | Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	749	510
60-89 Days [Member] | Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	293	107
60-89 Days [Member] | Originated [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	24	36
60-89 Days [Member] | Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	150	987
60-89 Days [Member] | Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	97	48
60-89 Days [Member] | PNCI [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,079	344
60-89 Days [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	415	90
60-89 Days [Member] | PNCI [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	192	254
60-89 Days [Member] | PNCI [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	472
60-89 Days [Member] | PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	397	90
60-89 Days [Member] | PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due		26
60-89 Days [Member] | PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	18
60-89 Days [Member] | PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	192	228
> 90 Days [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	2,687	2,518
> 90 Days [Member] | Originated [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	855	243
> 90 Days [Member] | Originated [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	523	748
> 90 Days [Member] | Originated [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,309	1,527
> 90 Days [Member] | Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	738	243
> 90 Days [Member] | Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	411	373
> 90 Days [Member] | Originated [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due		3
> 90 Days [Member] | Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	117
> 90 Days [Member] | Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	112	372
> 90 Days [Member] | PNCI [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,355	439
> 90 Days [Member] | PNCI [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	1,112	109
> 90 Days [Member] | PNCI [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	243	330
> 90 Days [Member] | PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	163	109
> 90 Days [Member] | PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	16
> 90 Days [Member] | PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	949
> 90 Days [Member] | PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past due	$ 227	$ 330

Allowance for Loan Losses - Add

Allowance for Loan Losses - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Originated [Member]
Loans and Leases Receivable Disclosure [Line Items]
Interest income on non accrual loans	$ 338,000	$ 244,000	$ 964,000	$ 617,000
Interest income on non accrual loans ,recognized	59,000	33,000	133,000	49,000
Impaired TDR Loans	8,845,000	13,352,000	8,845,000	13,352,000	$ 12,517,000
Obligations to lend additional funds on TDR	0	209,000	0	209,000	1,000
PNCI [Member]
Loans and Leases Receivable Disclosure [Line Items]
Interest income on non accrual loans	39,000	90,000	93,000	188,000
Interest income on non accrual loans ,recognized	12,000	2,000	23,000	14,000
Impaired TDR Loans	840,000	1,611,000	840,000	1,611,000	1,352,000
Obligations to lend additional funds on TDR	$ 0	$ 3,000	$ 0	$ 3,000	$ 0

Allowance for Loan Losses - S_3

Allowance for Loan Losses - Schedule of Non Accrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	$ 19,234	$ 16,925
Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	12,213	10,881
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	3,284	2,375
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	3,737	3,669
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	4,032	2,737
Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	1,983	1,150
Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	8	12
Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	8,181	8,144
Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	1,293	1,213
Originated [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	17,087	15,462
Originated [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	10,689	9,869
Originated [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	2,661	1,924
Originated [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	3,737	3,669
Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	2,813	1,725
Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	1,933	1,106
Originated [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	3	7
Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	7,876	8,144
Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	725	811
PNCI [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	2,147	1,463
PNCI [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	1,524	1,012
PNCI [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	623	451
PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	1,219	1,012
PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	50	44
PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	5	5
PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	305
PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans	$ 568	$ 402

Allowance for Loan Losses - Imp

Allowance for Loan Losses - Impaired Loans (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Originated [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	$ 25,607	$ 29,012	$ 26,175
Recorded investment with no related allowance	18,311	22,425	18,078
Recorded investment with related allowance	5,397	5,162	7,188
Total recorded investment	23,708	27,587	25,266
Related Allowance	2,234	1,563	2,232
Average recorded investment	23,292	25,787	24,626
Interest income recognized	409	712	1,052
Originated [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	16,738	22,132	18,209
Recorded investment with no related allowance	12,870	18,816	15,159
Recorded investment with related allowance	2,681	2,794	2,691
Total recorded investment	15,551	21,610	17,850
Related Allowance	325	240	260
Average recorded investment	15,432	19,232	17,352
Interest income recognized	275	604	788
Originated [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	4,001	3,474	3,260
Recorded investment with no related allowance	3,306	2,581	2,204
Recorded investment with related allowance	219	320	602
Total recorded investment	3,525	2,901	2,806
Related Allowance	52	53	124
Average recorded investment	3,166	2,963	2,915
Interest income recognized	56	32	71
Originated [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	4,868	3,262	4,566
Recorded investment with no related allowance	2,135	884	575
Recorded investment with related allowance	2,497	2,048	3,895
Total recorded investment	4,632	2,932	4,470
Related Allowance	1,857	1,270	1,848
Average recorded investment	4,626	3,514	4,283
Interest income recognized	78	69	184
Originated [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		144	140
Recorded investment with no related allowance		144	140
Total recorded investment		144	140
Average recorded investment	68	78	76
Interest income recognized		7	9
Originated [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	4,185	3,489	4,023
Recorded investment with no related allowance	3,251	1,777	2,058
Recorded investment with related allowance	311	1,644	1,881
Total recorded investment	3,562	3,421	3,939
Related Allowance	57	167	230
Average recorded investment	3,883	3,242	3,501
Interest income recognized	67	90	143
Originated [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	2,554	2,091	1,627
Recorded investment with no related allowance	1,960	1,470	1,107
Recorded investment with related allowance	157	199	198
Total recorded investment	2,117	1,669	1,305
Related Allowance	30	13	10
Average recorded investment	1,753	1,376	1,193
Interest income recognized	24	32	24
Originated [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	3	59	52
Recorded investment with no related allowance		3	4
Interest loss recognized		(25)
Recorded investment with related allowance	3	11	3
Total recorded investment	3	14	7
Related Allowance	3	7	3
Average recorded investment	3	23	20
Originated [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	12,553	18,643	14,186
Recorded investment with no related allowance	9,619	17,039	13,101
Recorded investment with related allowance	2,370	1,150	810
Total recorded investment	11,989	18,189	13,911
Related Allowance	268	73	30
Average recorded investment	11,549	15,990	13,851
Interest income recognized	208	514	645
Originated [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	1,444	1,324	1,581
Recorded investment with no related allowance	1,346	1,108	1,093
Recorded investment with related allowance	59	110	401
Total recorded investment	1,405	1,218	1,494
Related Allowance	19	33	111
Average recorded investment	1,410	1,564	1,702
Interest income recognized	32	25	47
Originated [Member] | Residential [Member] | Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		144	140
Recorded investment with no related allowance		144	140
Total recorded investment		144	140
Average recorded investment	68	78	76
Interest income recognized		7	9
PNCI [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	3,945	4,967	3,048
Recorded investment with no related allowance	3,149	3,399	1,994
Recorded investment with related allowance	637	1,233	974
Total recorded investment	3,786	4,632	2,968
Related Allowance	394	577	467
Average recorded investment	3,355	4,397	3,563
Interest income recognized	87	65	89
PNCI [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	2,557	3,503	1,404
Recorded investment with no related allowance	2,474	2,955	1,359
Recorded investment with related allowance		250
Total recorded investment	2,474	3,205	1,359
Related Allowance		73
Average recorded investment	1,902	2,943	2,020
Interest income recognized	58	24	24
PNCI [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	1,388	1,458	1,644
Recorded investment with no related allowance	675	444	635
Recorded investment with related allowance	637	983	974
Total recorded investment	1,312	1,427	1,609
Related Allowance	394	498	467
Average recorded investment	1,453	1,451	1,543
Interest income recognized	29	41	65
PNCI [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance		6
Related Allowance		6
Average recorded investment		3
PNCI [Member] | Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	1,302	1,634	1,404
Recorded investment with no related allowance	1,219	1,356	1,359
Recorded investment with related allowance		250
Total recorded investment	1,219	1,606	1,359
Related Allowance		73
Average recorded investment	1,275	1,165	1,041
Interest income recognized		24	24
PNCI [Member] | Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	296	185	178
Recorded investment with no related allowance	50	50	44
Recorded investment with related allowance	239	123	121
Total recorded investment	289	173	165
Related Allowance	145	99	97
Average recorded investment	287	121	117
Interest income recognized	9	5	6
PNCI [Member] | Other Consumer [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	240	253	250
Recorded investment with related allowance	240	253	250
Total recorded investment	240	253	250
Related Allowance	100	71	54
Average recorded investment	257	187	186
Interest income recognized	7	8	11
PNCI [Member] | Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	1,255	1,869
Recorded investment with no related allowance	1,255	1,599
Total recorded investment	1,255	1,599
Average recorded investment	627	1,778	979
Interest income recognized	58
PNCI [Member] | Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance	852	1,020	1,216
Recorded investment with no related allowance	625	394	591
Recorded investment with related allowance	158	607	603
Total recorded investment	783	1,001	1,194
Related Allowance	149	328	316
Average recorded investment	909	1,143	1,240
Interest income recognized	$ 13	$ 28	$ 48

Allowance for Loan Losses - TDR

Allowance for Loan Losses - TDRs (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)SecurityLoan	Sep. 30, 2017USD ($)SecurityLoan	Sep. 30, 2018USD ($)SecurityLoan	Sep. 30, 2017USD ($)SecurityLoan
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	7	15	13	25
Pre-mod outstanding principal balance	$ 2,007	$ 5,330	$ 3,094	$ 6,899
Post-mod outstanding principal balance	2,005	5,330	3,101	6,766
Financial impact due to TDR taken as additional provision	$ (308)	$ 211	$ (265)	$ 133
Number that defaulted during the period | SecurityLoan	1	2	6	3
Recorded investment of TDRs that defaulted during the period	$ 128	$ 318	$ 637	$ 442
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions			$ (2)
Mortgage Loans on Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	4	5	6	8
Pre-mod outstanding principal balance	$ 1,326	$ 3,825	$ 1,743	$ 4,448
Post-mod outstanding principal balance	1,324	3,825	1,741	4,421
Financial impact due to TDR taken as additional provision	$ (308)	$ 183	$ (262)	$ 58
Number that defaulted during the period | SecurityLoan		2	1	3
Recorded investment of TDRs that defaulted during the period		$ 318	$ 169	$ 442
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1	1	3	5
Pre-mod outstanding principal balance	$ 478	$ 252	$ 732	$ 453
Post-mod outstanding principal balance	$ 478	$ 252	$ 737	453
Financial impact due to TDR taken as additional provision				$ 38
Number that defaulted during the period | SecurityLoan	1		1
Recorded investment of TDRs that defaulted during the period	$ 128		$ 128
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	2	8	4	11
Pre-mod outstanding principal balance	$ 203	$ 1,109	$ 619	$ 1,854
Post-mod outstanding principal balance	$ 203	1,109	623	1,748
Financial impact due to TDR taken as additional provision		$ 28	$ (3)	$ 37
Number that defaulted during the period | SecurityLoan			4
Recorded investment of TDRs that defaulted during the period			$ 340
Financial impact due to the default of previous TDR taken as charge-offs or additional provisions			$ (2)
Construction [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan		1		1
Pre-mod outstanding principal balance		$ 144		$ 144
Post-mod outstanding principal balance		$ 144		$ 144
Residential 1-4 Family [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan		1		1
Pre-mod outstanding principal balance		$ 939		$ 939
Post-mod outstanding principal balance		939		939
Financial impact due to TDR taken as additional provision		$ 169		$ 169
Number that defaulted during the period | SecurityLoan		1		2
Recorded investment of TDRs that defaulted during the period		$ 99		$ 223
Home Equity Loans [Member] | Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1	1	2	1
Pre-mod outstanding principal balance	$ 478	$ 252	$ 599	$ 252
Post-mod outstanding principal balance	$ 478	$ 252	$ 599	$ 252
Other Consumer [Member] | Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan				1
Pre-mod outstanding principal balance				$ 14
Post-mod outstanding principal balance				14
Financial impact due to TDR taken as additional provision				$ 11
Commercial [Member] | Mortgage Loans on Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	4	4	6	7
Pre-mod outstanding principal balance	$ 1,326	$ 2,886	$ 1,743	$ 3,509
Post-mod outstanding principal balance	1,324	2,886	1,741	3,482
Financial impact due to TDR taken as additional provision	$ (308)	$ 14	$ (262)	$ (111)
Number that defaulted during the period | SecurityLoan		1	1	1
Recorded investment of TDRs that defaulted during the period		$ 219	$ 169	$ 219
Home Equity Lines of Credit [Member] | Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan			1	3
Pre-mod outstanding principal balance			$ 133	$ 187
Post-mod outstanding principal balance			$ 138	187
Financial impact due to TDR taken as additional provision				$ 27
Number that defaulted during the period | SecurityLoan	1		1
Recorded investment of TDRs that defaulted during the period	$ 128		$ 128
Residential [Member] | Construction [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan		1		1
Pre-mod outstanding principal balance		$ 144		$ 144
Post-mod outstanding principal balance		$ 144		$ 144

Foreclosed Assets - Summary of

Foreclosed Assets - Summary of Activity in Balance of Foreclosed Assets (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Assets	Sep. 30, 2017USD ($)Assets
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance, net			$ 3,226	$ 3,986
Additions/transfers from loans			536	726
Dispositions/sales			(1,841)	(1,479)
Valuation adjustments			(89)	(162)
Ending balance, net	$ 1,832	$ 3,071	1,832	3,071
Ending valuation allowance			$ (143)	$ (248)
Ending number of foreclosed assets | Assets			11	11
Proceeds from sale of foreclosed assets			$ 2,206	$ 1,787
Gain on sale of foreclosed assets	$ 2	$ 37	$ 390	$ 308

Foreclosed Assets - Additional

Foreclosed Assets - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Schedule Of Foreclosed Assets Activity [Line Items]
Foreclosed assets	$ 1,832,000	$ 3,226,000	$ 3,071,000	$ 3,986,000
Residential Real Estate [Member]
Schedule Of Foreclosed Assets Activity [Line Items]
Foreclosed assets	1,269,000
Formal foreclosure proceedings	$ 477,000

Premises and Equipment - Summar

Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment, Net, by Type [Abstract]
Land & land improvements	$ 28,958	$ 9,959
Buildings	64,178	50,340
Furniture and equipment	44,271	35,939
Premises and equipment, gross	137,407	96,238
Less: Accumulated depreciation	(49,073)	(40,644)
Premises and equipment less depreciation, gross	88,334	55,594
Construction in progress	956	2,148
Total premises and equipment	$ 89,290	$ 57,742

Premises and Equipment - Additi

Premises and Equipment - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Depreciation expense for premises and equipment	$ 1,685,000	$ 1,520,000	$ 4,442,000	$ 4,224,000

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Summary of Goodwill Intangible (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, Ending Balance	$ 220,972
Goodwill, Additions	156,661
Goodwill, Reductions	0
Goodwill, Beginning Balance	$ 64,311

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Summary of Core Deposit Intangibles (CDI) (Detail) - Core Deposit Intangibles [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Finite-Lived Intangible Assets [Line Items]
Core deposit intangibles, Beginning balance	$ 9,558
Core deposit intangibles, Reductions/Amortization	0
Core deposit intangibles, Additions	27,605
Core deposit intangibles, Ending balance	37,163
Accumulated amortization, Beginning balance	(4,384)
Accumulated amortization, Reductions/Amortization	(2,068)
Accumulated amortization, Additions	0
Accumulated amortization, Ending balance	(6,452)
Core deposit intangibles, net, Beginning balance	5,174
Core deposit intangibles, net, Reductions/Amortization	(2,068)
Core deposit intangibles, net, Additions	27,605
Core deposit intangibles, net, Ending balance	$ 30,711

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Additional Information (Detail)	Jul. 06, 2018USD ($)
FNBB [Member]
Finite-Lived Intangible Assets [Line Items]
Additions to core deposit intangibles	$ 27,605,000

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Remaining Estimated Core Deposit Intangible Amortization (Detail) - Core Deposit Intangibles [Member] $ in Thousands	Sep. 30, 2018USD ($)
Finite-Lived Intangible Assets [Line Items]
2,018	$ 1,431
2,019	5,723
2,020	5,723
2,021	5,465
2,022	4,776
Thereafter	$ 7,593

Other Assets - Summary of Other

Other Assets - Summary of Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred tax asset, net	$ 31,963	$ 21,697
Investment in low income housing tax credit funds	23,572	16,854
Prepaid expense	3,420	4,111
Tax refund receivable	2,836	4,754
Capital trusts	1,712	1,706
Software	762	1,126
Life insurance proceeds receivable		2,242
Miscellaneous other assets	6,332	2,561
Total other assets	$ 70,597	$ 55,051

Deposits - Summary of Balances

Deposits - Summary of Balances of Deposits (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Noninterest-bearing demand	$ 1,710,505	$ 1,368,218
Interest-bearing demand	1,152,705	971,459
Savings	1,801,087	1,364,518
Time certificates, over $250,000	140,805	73,596
Other time certificates	288,015	231,340
Total deposits	$ 5,093,117	$ 4,009,131

Deposits - Additional Informati

Deposits - Additional Information (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Schedule Of Deposits [Line Items]
Overdrawn deposit balances classified as consumer loans	$ 1,375,000	$ 1,366,000
California [Member]
Schedule Of Deposits [Line Items]
Certificate of deposits, included in time certificates, over $250,000	$ 69,000,000	$ 50,000,000

Other Liabilities - Components

Other Liabilities - Components of Other Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Pension liability	$ 37,789	$ 28,472
Low income housing tax credit fund commitments	9,146	8,554
Deferred compensation	9,450	6,605
Accrued salaries and benefits expense	8,990	6,619
Joint beneficiary agreements	3,558	3,365
Loan escrow and servicing payable	2,821	1,958
Deferred revenue	1,978	1,228
Litigation contingency		1,450
Miscellaneous other liabilities	8,345	8,171
Total other liabilities	$ 82,077	$ 66,422

Commitments and Contingencies -

Commitments and Contingencies - Future Minimum Commitments under Non-Cancelable Operating Leases with Initial or Remaining Terms of One Year or More (Detail) $ in Thousands	Sep. 30, 2018USD ($)
Leases [Abstract]
2,018	$ 1,179
2,019	4,478
2,020	3,774
2,021	3,372
2,022	2,549
Thereafter	4,097
Future minimum lease payments	$ 19,449

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Bank's Commitments and Contingent Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit
Construction [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit	283,858	187,097
RE Mortgage [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit	149,003	66,267
Standby Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit	11,277	13,075
Commercial [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit	310,844	257,220
Consumer Loans [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit	481,837	422,958
Deposit Account Overdraft Privilege [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commitments to extend credit	$ 107,956	$ 98,260

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Aug. 21, 2007
Class of Stock [Line Items]
Repurchase of common stock							500,000
Stock repurchase plan percentage of common stock							3.20%
Common stock, shares outstanding	30,417,818		30,417,818		22,955,963		15,814,662
Market value of shares repurchased			$ 1,124,000	$ 3,854,000
Maximum [Member]
Class of Stock [Line Items]
Amount available to dividend to holding company					$ 85,254,000
Tri Counties Bank [Member]
Class of Stock [Line Items]
Cash dividends received	$ 13,507,000	$ 5,185,000	$ 22,649,000	$ 14,394,000
2007 Stock Repurchase Plan [Member]
Class of Stock [Line Items]
Repurchased shares outstanding	166,600		166,600
Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares outstanding	30,417,818	22,941,464	30,417,818	22,941,464	22,955,963	22,867,802
Company's common stock in lieu of cash to exercise options to purchase shares	11,630	21,738	28,850	107,390
Market value of shares repurchased	$ 453,000	$ 762,000	$ 1,124,000	$ 3,854,000

Stock Options and Other Equit_3

Stock Options and Other Equity-Based Incentive Instruments - Stock Option Activity (Detail)	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Number of Shares, beginning balance | shares	446,400
Options granted, Number of Shares | shares	0
Options exercised, Number of Shares | shares	(27,400)
Options forfeited, Number of Shares | shares	(3,000)
Options outstanding, Number of Shares, ending balance | shares	416,000
Options outstanding, Weighted Average Exercise Price, beginning balance	$ 16.84
Options granted, Weighted Average Exercise Price	0
Options exercised, Weighted Average Exercise Price	17.33
Options forfeited, Weighted Average Exercise Price	23.21
Options outstanding, Weighted Average Exercise Price, ending balance	16.77
Minimum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Option Price per Share, beginning balance	12.63
Options granted, Option Price per Share	0
Options exercised, Option Price per Share	15.34
Options forfeited, Option Price per Share	23.21
Options outstanding, Option Price per Share, ending balance	12.63
Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, Option Price per Share, beginning balance	23.21
Options granted, Option Price per Share	0
Options exercised, Option Price per Share	23.21
Options forfeited, Option Price per Share	23.21
Options outstanding, Option Price per Share, ending balance	$ 23.21

Stock Options and Other Equit_4

Stock Options and Other Equity-Based Incentive Instruments - Summary of Options Outstanding (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options	416,000	446,400
Weighted average exercise price	$ 16.77	$ 16.84
Intrinsic value (in thousands)	$ 9,091
Weighted average remaining contractual term (yrs.)	3 years 2 months 12 days
Currently Exercisable [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options	413,000
Weighted average exercise price	$ 16.72
Intrinsic value (in thousands)	$ 9,045
Weighted average remaining contractual term (yrs.)	3 years 2 months 12 days
Currently Not Exercisable [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options	3,000
Weighted average exercise price	$ 23.21
Intrinsic value (in thousands)	$ 46
Weighted average remaining contractual term (yrs.)	6 years

Stock Options and Other Equit_5

Stock Options and Other Equity-Based Incentive Instruments - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options currently not exercisable yet expected to vest	3,000
Restricted Stock Units (RSUs) [Member] | Service Condition Vesting RSUs [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of units outstanding expected to vest	70,608	68,457
Weighted-average remaining contractual term	1 year 7 months 6 days
Pre-tax compensation costs	$ 2,063,000
Number of units released	32,516
Restricted Stock Units (RSUs) [Member] | Market Plus Service Condition Vesting RSUs [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of units outstanding expected to vest	47,284	52,829
Weighted-average remaining contractual term	1 year 8 months 12 days
Pre-tax compensation costs	$ 902,000
Number of units released	25,512
Minimum [Member] | Restricted Stock Units (RSUs) [Member] | Market Plus Service Condition Vesting RSUs [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of units released	0
Maximum [Member] | Restricted Stock Units (RSUs) [Member] | Market Plus Service Condition Vesting RSUs [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of units released	70,926

Stock Options and Other Equit_6

Stock Options and Other Equity-Based Incentive Instruments - Restricted Stock Unit (RSU) Activity (Detail) - Restricted Stock Units (RSUs) [Member]	9 Months Ended
	Sep. 30, 2018$ / sharesshares
Market Plus Service Condition Vesting RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs outstanding, Number of RSUs, beginning balance	52,829
RSUs granted, Number of RSUs	16,939
Additional market plus service condition RSUs vested, Number of RSUs	8,506
RSUs released through vesting, Number of RSUs	(25,512)
RSUs forfeited/expired, Number of RSUs	(5,478)
RSUs outstanding, Number of RSUs, ending balance	47,284
RSUs granted, Weighted Average Fair Value on Date of Grant | $ / shares	$ 36.40
Service Condition Vesting RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs outstanding, Number of RSUs, beginning balance	68,457
RSUs granted, Number of RSUs	38,605
RSUs added through dividend credits, Number of RSUs	806
RSUs released through vesting, Number of RSUs	(32,516)
RSUs forfeited/expired, Number of RSUs	(4,744)
RSUs outstanding, Number of RSUs, ending balance	70,608
RSUs granted, Weighted Average Fair Value on Date of Grant | $ / shares	$ 39.08

Noninterest Income and Expens_2

Noninterest Income and Expense - Components of Other Noninterest Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	$ 9,743	$ 9,475	$ 28,327	$ 27,861
Commissions on sale of non-deposit investment products	728	672	2,414	1,984
Increase in cash value of life insurance	732	732	1,996	2,043
Gain on sale of loans	539	606	1,831	2,293
Lease brokerage income	186	234	514	601
Gain on sale of foreclosed assets	2	37	390	308
Sale of customer checks	88	89	327	287
Gain on sale of investment securities	207	961	207	961
Loss on disposal of fixed assets	(152)	(33)	(206)	(61)
Loss on marketable equity securities	(22)		(92)
Other	135	157	942	1,266
Total other noninterest income	2,443	3,455	8,323	9,682
Total noninterest income	12,186	12,930	36,650	37,543
ATM and Interchange Fees [Member]
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	4,590	4,209	13,335	12,472
Service Charges on Deposit Accounts [Member]
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	4,015	4,160	11,407	12,102
Other Service Fees [Member]
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	676	917	2,020	2,521
Mortgage Banking Service Fees [Member]
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	499	514	1,527	1,561
Change in Value of Mortgage Servicing Rights [Member]
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	$ (37)	$ (325)	$ 38	$ (795)

Noninterest Income and Expens_3

Noninterest Income and Expense - Components of Noninterest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Base salaries, net of deferred loan origination costs	$ 17,051	$ 13,600	$ 45,442	$ 40,647
Incentive compensation	3,223	2,609	7,834	6,980
Benefits and other compensation costs	5,549	4,724	15,652	14,693
Total salaries and benefits expense	25,823	20,933	68,928	62,320
Occupancy	3,173	2,799	8,574	8,196
Data processing and software	2,786	2,495	7,979	7,332
Merger and acquisition expense	4,150		5,227
Equipment	1,750	1,816	4,938	5,344
ATM and POS network charges	1,195	1,425	3,858	3,353
Advertising	1,341	1,039	3,214	3,173
Professional fees	929	901	2,475	2,357
Telecommunications	819	716	2,201	2,027
Regulatory assessments and insurance	537	427	1,384	1,252
Intangible amortization	1,390	339	2,068	1,050
Postage	275	325	934	1,058
Courier service	278	235	769	752
Operational losses	217	301	763	1,166
Foreclosed assets expense	93	41	297	117
Provision for (reversal of) foreclosed asset losses	(1)	134	89	162
Other miscellaneous expense	2,623	3,296	9,712	9,289
Total other noninterest expense	21,555	16,289	54,482	46,628
Total noninterest expense	$ 47,378	$ 37,222	$ 123,410	$ 108,948

Earnings Per Share - Computatio

Earnings Per Share - Computation of Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 16,170	$ 11,897	$ 45,109	$ 37,565
Average number of common shares outstanding	30,011	22,932	25,317	22,901
Effect of dilutive stock options and restricted stock	280	312	300	338
Average number of common shares outstanding used to calculate diluted earnings per share	30,291	23,244	25,617	23,239
Options excluded from diluted earnings per share because the effect of these options was antidilutive	10,000		10,000

Comprehensive Income - Componen

Comprehensive Income - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (26,959)	$ (5,228)
Net Unrealized Loss on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, before tax	(33,051)	(3,409)
Accumulated other comprehensive loss, tax effect	9,771	1,433
Accumulated other comprehensive loss	(23,280)	(1,976)
Unfunded Status of Supplemental Retirement Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, before tax	(5,010)	(5,352)
Accumulated other comprehensive loss, tax effect	1,481	2,250
Accumulated other comprehensive loss	(3,529)	(3,102)
Joint Beneficiary Agreement Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, before tax	(150)	(150)
Accumulated other comprehensive loss	$ (150)	$ (150)

Comprehensive Income - Compon_2

Comprehensive Income - Components of Other Comprehensive Income (Loss) and Related Tax Effects (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized holding gains (losses) on available for sale securities before reclassifications	$ (8,193)	$ 674	$ (29,134)	$ 6,372
Amounts reclassified out of accumulated other comprehensive income:
Realized gains on debt securities	(207)	(961)	(207)	(961)
Total amounts reclassified out of accumulated other comprehensive income	(207)	(961)	(570)	(961)
Unrealized holding gains (losses) on available for sale securities after reclassifications	(8,400)	(287)	(29,704)	5,411
Tax effect	2,483	121	8,763	(2,274)
Unrealized holding gains (losses) on available for sale securities, net of tax	(5,917)	(166)	(20,941)	3,137
Change in unfunded status of the supplemental retirement plans before reclassifications			668
Amounts reclassified out of accumulated other comprehensive income:
Amortization of prior service cost	(13)	(1)	(40)	(5)
Amortization of actuarial losses	128	96	382	288
Total amounts reclassified out of accumulated other comprehensive income	115	95	(326)	283
Change in unfunded status of the supplemental retirement plans after reclassifications	115	95	342	283
Tax effect	(34)	(40)	(101)	(119)
Change in unfunded status of the supplemental retirement plans, net of tax	81	55	241	164
Total other comprehensive income (loss)	$ (5,836)	$ (111)	(20,700)	$ 3,301
ASU 2016-01 [Member]
Amounts reclassified out of accumulated other comprehensive income:
Total amounts reclassified out of accumulated other comprehensive income			62
ASU 2018-02 [Member]
Amounts reclassified out of accumulated other comprehensive income:
Total amounts reclassified out of accumulated other comprehensive income			(425)
Amounts reclassified out of accumulated other comprehensive income:
Total amounts reclassified out of accumulated other comprehensive income			$ (668)

Fair Value Measurement - Record

Fair Value Measurement - Recorded Amount of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value Measurements on Recurring Basis [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 1,069,752	$ 742,186
Marketable Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	2,846	2,938
Obligations of U.S. Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	638,876	604,789
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	123,420	123,156
Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	7,122	6,687
Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	4,431
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	289,233
Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	3,824	4,616
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	2,846	2,938
Level 1 [Member] | Marketable Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	2,846	2,938
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	1,059,784	732,561
Level 2 [Member] | Obligations of U.S. Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	638,876	604,789
Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	123,420	123,156
Level 2 [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	4,431
Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	289,233
Level 2 [Member] | Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	3,824	4,616
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	7,122	6,687
Level 3 [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 7,122	$ 6,687

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Transfers between level 1 to level 2, Assets	$ 0	$ 0
Transfers between level 2 to level 1, Assets	0	0
Transfers between level 1 to level 2, Liabilities	0	0
Transfers between level 2 to level 1, Liabilities	0	0
Transfer into level 3	0	0
Transfer out of level 3	0	$ 0
Carrying value of loans fully charged-off	$ 0

Fair Value Measurement - Reconc

Fair Value Measurement - Reconciliation of Assets and Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) on Recurring Basis (Detail) - Mortgage Servicing Rights [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 7,021	$ 6,596	$ 6,687	$ 6,595
Transfers into (out of) Level 3	0	0	0	0
Change Included in Earnings	(37)	(325)	38	(795)
Issuances	138	148	397	619
Ending Balance	$ 7,122	$ 6,419	$ 7,122	$ 6,419

Fair Value Measurement - Quanti

Fair Value Measurement - Quantitative Information about Recurring Level 3 Fair Value Measurements (Detail) - Mortgage Servicing Rights [Member] $ in Thousands	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgages Servicing Rights, Fair Value	$ 7,122	$ 6,687
Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.048	0.062
Minimum [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.12	0.13
Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.330	0.220
Maximum [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.12	0.15
Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Constant Prepayment Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.073	0.089
Weighted Average [Member] | Valuation Technique, Discounted Cash Flow [Member] | Measurement Input, Discount Rate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Constant prepayment rate	0.12	0.13

Fair Value Measurement - Assets

Fair Value Measurement - Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 445		$ 2,767
Fair Value Nonrecurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	1,308	$ 3,088	4,984
Total Gains/(Losses)	(831)	(1,049)	(1,587)
Fair Value Nonrecurring Basis [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	445	1,026	2,767
Total Gains/(Losses)	(808)	(892)	(1,452)
Fair Value Nonrecurring Basis [Member] | Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	863	2,062	2,217
Total Gains/(Losses)	(23)	(157)	(135)
Fair Value Nonrecurring Basis [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	1,308	3,088	4,984
Fair Value Nonrecurring Basis [Member] | Level 3 [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	445	1,026	2,767
Fair Value Nonrecurring Basis [Member] | Level 3 [Member] | Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 863	$ 2,062	$ 2,217

Fair Value Measurement - Quan_2

Fair Value Measurement - Quantitative Information about Level 3 Fair Value Measurements for Financial Instruments Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Impaired Originated & PNCI Loans [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 445	$ 2,767
Foreclosed Assets [Member] | Land & Construction [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	27	1,341
Foreclosed Assets [Member] | Residential Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	744	622
Foreclosed Assets [Member] | Commercial Real Estate [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value	$ 92	$ 254
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Impaired Originated & PNCI Loans [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	(55.80%)	(74.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Foreclosed Assets [Member] | Land & Construction [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average		(53.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Foreclosed Assets [Member] | Residential Real Estate [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	(47.00%)	(47.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Foreclosed Assets [Member] | Commercial Real Estate [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	(65.00%)	(84.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Impaired Originated & PNCI Loans [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	60.00%	23.00%
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Foreclosed Assets [Member] | Land & Construction [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average		283.00%
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Foreclosed Assets [Member] | Residential Real Estate [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	52.00%	39.00%
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Foreclosed Assets [Member] | Commercial Real Estate [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	20.00%	19.00%
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Impaired Originated & PNCI Loans [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	(28.00%)	(19.76%)
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Foreclosed Assets [Member] | Land & Construction [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average		167.00%
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Foreclosed Assets [Member] | Residential Real Estate [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	0.90%	(3.13%)
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Foreclosed Assets [Member] | Commercial Real Estate [Member] | Adjustment for Differences between Comparable Sales [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted average	(45.00%)	(84.00%)

Fair Value Measurement - Estima

Fair Value Measurement - Estimated Fair Values of Financial Instruments that are Reported at Amortized Cost in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial assets:
Cash and due from banks	$ 109,363	$ 105,968
Cash at Federal Reserve and other banks	117,180	99,460
Securities held to maturity	459,897	514,844
Financial liabilities:
Other borrowings	282,831	122,166
Junior subordinated debt	56,996	56,858
Level 3 [Member] | Overdraft Privilege Commitments [Member]
Off-balance sheet:
Contract amount, Off-balance sheet	107,956	98,260
Level 3 [Member] | Standby Letters of Credit [Member]
Off-balance sheet:
Contract amount, Off-balance sheet	11,277	13,075
Level 3 [Member] | Commitments [Member]
Off-balance sheet:
Contract amount, Off-balance sheet	1,225,542	933,542
Fair Value [Member] | Level 3 [Member]
Financial assets:
Loans, net	3,987,841	2,992,225
Financial liabilities:
Junior subordinated debt	58,930	58,466
Fair Value [Member] | Level 3 [Member] | Overdraft Privilege Commitments [Member]
Off-balance sheet:
Fair value, Off-balance sheet	1,080	983
Fair Value [Member] | Level 3 [Member] | Standby Letters of Credit [Member]
Off-balance sheet:
Fair value, Off-balance sheet	113	131
Fair Value [Member] | Level 3 [Member] | Commitments [Member]
Off-balance sheet:
Fair value, Off-balance sheet	12,255	9,335
Fair Value [Member] | Level 1 [Member]
Financial assets:
Cash and due from banks	109,363	105,968
Cash at Federal Reserve and other banks	117,180	99,460
Fair Value [Member] | Level 2 [Member]
Financial assets:
Securities held to maturity	446,287	518,165
Financial liabilities:
Deposits	5,088,024	4,006,620
Other borrowings	282,831	122,166
Carrying Amount [Member] | Level 3 [Member]
Financial assets:
Loans, net	3,995,833	2,984,842
Financial liabilities:
Junior subordinated debt	56,996	56,858
Carrying Amount [Member] | Level 1 [Member]
Financial assets:
Cash and due from banks	109,363	105,968
Cash at Federal Reserve and other banks	117,180	99,460
Carrying Amount [Member] | Level 2 [Member]
Financial assets:
Securities held to maturity	459,897	514,844
Restricted equity securities	17,250	16,956
Financial liabilities:
Deposits	5,093,117	4,009,131
Other borrowings	$ 282,831	$ 122,166

Regulatory Matters - Actual and

Regulatory Matters - Actual and Required Capital Ratios of Bank (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	8.00%	8.00%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%	6.50%
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%
Parent [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Actual, Amount	$ 664,197	$ 528,805
Tier 1 Capital (to Risk Weighted Assets), Actual, Amount	630,294	495,318
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual, Amount	575,010	440,643
Tier 1 Capital (to Average Assets), Actual, Amount	$ 630,294	$ 495,318
Total Capital (to Risk Weighted Assets), Actual, Ratio	13.90%	14.07%
Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio	13.19%	13.18%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio	12.03%	11.72%
Tier 1 Capital (to Average Assets), Actual, Ratio	10.66%	10.80%
Parent [Member] | Basel III Phase-in Schedule [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	$ 471,956	$ 347,694
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	376,370	272,517
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	304,680	216,134
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount	$ 236,503	$ 183,400
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	9.875%	9.25%
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	7.875%	7.25%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	6.375%	5.75%
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%
Parent [Member] | Basel III Fully Phased In [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	$ 501,826	$ 394,679
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	406,240	319,502
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	334,551	263,120
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount	$ 236,503	$ 183,400
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	10.50%	10.50%
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	8.50%	8.50%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	7.00%	7.00%
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%
Tri Countries Bank [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Actual, Amount	$ 658,075	$ 525,384
Tier 1 Capital (to Risk Weighted Assets), Actual, Amount	624,172	491,897
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual, Amount	624,172	491,897
Tier 1 Capital (to Average Assets), Actual, Amount	$ 624,172	$ 491,897
Total Capital (to Risk Weighted Assets), Actual, Ratio	13.77%	13.98%
Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio	13.06%	13.09%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual, Ratio	13.06%	13.09%
Tier 1 Capital (to Average Assets), Actual, Ratio	10.56%	10.73%
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 477,756	$ 375,713
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	382,205	300,570
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	310,541	244,214
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	295,620	229,243
Tri Countries Bank [Member] | Basel III Phase-in Schedule [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	471,784	347,535
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	376,233	272,392
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	304,569	216,035
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount	$ 236,496	$ 183,394
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	9.875%	9.25%
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	7.875%	7.25%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	6.375%	5.75%
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%
Tri Countries Bank [Member] | Basel III Fully Phased In [Member]
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	$ 501,643	$ 394,499
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	406,092	319,356
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Amount	334,429	262,999
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Amount	$ 236,496	$ 183,394
Total Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	10.50%	10.50%
Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	8.50%	8.50%
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum Capital Requirement, Ratio	7.00%	7.00%
Tier 1 Capital (to Average Assets), Minimum Capital Requirement, Ratio	4.00%	4.00%

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail)	Dec. 31, 2019	Sep. 30, 2018
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Increase in risk-based capital ratios		0.625%
Scenario, Forecast [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Minimum capital level requirements, Tier 1 capital ratio	8.50%
Minimum capital level requirements, Total capital ratio	10.50%
Scenario, Forecast [Member] | Common Stock [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Minimum capital level requirements, Tier 1 capital ratio	7.00%