First Commonwealth Financial (FCF) 10-Q 9 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Aug. 08, 2016
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Trading Symbol	FCF
Entity Registrant Name	FIRST COMMONWEALTH FINANCIAL CORP /PA/
Entity Central Index Key	712,537
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		88,949,995

Condensed Consolidated Statemen

Condensed Consolidated Statements of Financial Condition (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 68,163	$ 66,644
Interest-bearing bank deposits	30,457	2,808
Securities available for sale, at fair value	855,333	886,560
Securities held to maturity, at amortized cost (Fair value of $414,770 and $382,341 at June 30, 2016 and December 31, 2015, respectively)	405,976	384,324
Other investments	58,087	62,952
Loans held for sale	11,613	5,763
Loans:
Portfolio loans	4,843,776	4,683,750
Allowance for credit losses	(59,821)	(50,812)
Net loans	4,783,955	4,632,938
Premises and equipment, net	63,921	63,454
Other real estate owned	8,604	9,398
Goodwill	164,500	164,500
Amortizing intangibles, net	981	1,231
Bank owned life insurance	184,684	182,601
Other assets	113,547	103,717
Total assets	6,749,821	6,566,890
Deposits (all domestic):
Noninterest-bearing	1,136,629	1,116,689
Interest-bearing	3,257,891	3,079,205
Total deposits	4,394,520	4,195,894
Short-term borrowings	1,464,687	1,510,825
Subordinated debentures	72,167	72,167
Other long-term debt	9,034	9,314
Total long-term debt	81,201	81,481
Other liabilities	67,627	59,144
Total liabilities	6,008,035	5,847,344
Shareholders’ Equity
Preferred stock, $1 par value per share, 3,000,000 shares authorized, none issued	0	0
Common stock, $1 par value per share, 200,000,000 shares authorized; 105,563,455 shares issued at June 30, 2016 and December 31, 2015, and 88,949,995 and 88,961,268 shares outstanding at June 30, 2016 and December 31, 2015, respectively	105,563	105,563
Additional paid-in capital	366,181	365,981
Retained earnings	390,110	378,081
Accumulated other comprehensive income (loss), net	7,947	(2,386)
Treasury stock (16,613,460 and 16,602,187 shares at June 30, 2016 and December 31, 2015, respectively)	(128,015)	(127,693)
Total shareholders’ equity	741,786	719,546
Total liabilities and shareholders’ equity	$ 6,749,821	$ 6,566,890

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Financial Condition (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	3,000,000	3,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	105,563,455	105,563,455
Common stock, shares outstanding (in shares)	88,959,315	88,961,268
Treasury stock, shares (in shares)	16,604,140	16,602,187
Securities held to maturity, fair value	$ 414,770	$ 382,341

Condensed Consolidated Stateme4

Condensed Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest Income
Interest and fees on loans	$ 45,698	$ 42,650	$ 90,732	$ 85,251
Interest and dividends on investments:
Taxable interest	7,028	6,735	14,174	13,552
Interest exempt from federal income taxes	371	210	732	385
Dividends	748	553	1,554	2,042
Interest on bank deposits	5	2	11	5
Total interest income	53,850	50,150	107,203	101,235
Interest Expense
Interest on deposits	1,928	1,880	3,517	4,030
Interest on short-term borrowings	2,100	1,116	4,335	2,074
Interest on subordinated debentures	644	579	1,278	1,148
Interest on other long-term debt	87	205	175	441
Total interest expense	4,759	3,780	9,305	7,693
Net Interest Income	49,091	46,370	97,898	93,542
Provision for credit losses	10,372	3,038	16,898	4,197
Net Interest Income after Provision for Credit Losses	38,719	43,332	81,000	89,345
Noninterest Income
Net securities gains	28	20	28	125
Trust income	1,320	1,476	2,575	2,897
Service charges on deposit accounts	3,845	3,872	7,553	7,190
Insurance and retail brokerage commissions	1,985	2,178	3,944	4,373
Income from bank owned life insurance	1,311	1,378	2,607	2,732
Gain on sale of mortgage loans	932	585	1,615	1,024
Gain on sale of other loans and assets	466	396	661	620
Card-related interchange income	3,784	3,729	7,341	7,147
Derivatives mark to market	(531)	593	(1,545)	363
Derivative Fee Income	800	283	1,260	643
Other income	1,618	1,837	3,234	3,424
Total noninterest income	15,558	16,347	29,273	30,538
Noninterest Expense
Salaries and employee benefits	19,888	22,001	41,565	43,893
Net occupancy expense	3,186	3,316	6,667	7,227
Furniture and equipment expense	2,882	2,630	5,749	5,310
Data processing expense	1,788	1,509	3,547	2,947
Pennsylvania shares tax expense	1,092	1,110	1,850	1,904
Intangible amortization	114	156	251	312
Collection and repossession expense	474	917	1,043	1,428
Other professional fees and services	913	945	1,704	1,875
FDIC insurance	1,062	1,025	2,100	2,084
Loss on sale or write-down of assets	345	1,635	441	1,897
Litigation and operational losses	635	323	879	1,323
Other operating expenses	5,031	5,067	9,758	10,288
Total noninterest expense	37,410	40,634	75,554	80,488
Income Before Income Taxes	16,867	19,045	34,719	39,395
Income tax provision	4,860	5,598	10,239	11,727
Net Income	$ 12,007	$ 13,447	$ 24,480	$ 27,668
Average Shares Outstanding (in shares)	88,831,758	88,922,392	88,835,923	89,893,662
Average Shares Outstanding Assuming Dilution (in shares)	88,838,614	88,939,003	88,840,683	89,903,550
Per Share Data:
Basic Earnings per Share (in dollars per share)	$ 0.14	$ 0.15	$ 0.28	$ 0.31
Diluted Earnings per Share (in dollars per share)	0.14	0.15	0.28	0.31
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.07	$ 0.07	$ 0.14	$ 0.14

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Income	$ 12,007	$ 13,447	$ 24,480	$ 27,668
Other comprehensive income (loss), before tax (expense) benefit:
Unrealized holding gains (losses) on securities arising during the period	3,802	(3,814)	13,872	6,166
Less: reclassification adjustment for gains on securities included in net income	(28)	(20)	(28)	(125)
Unrealized holding gains (losses) on derivatives arising during the period	359	(527)	2,094	668
Less: reclassification adjustment for gains on derivatives included in net income	(26)	(11)	(41)	(6)
Total other comprehensive income (loss), before tax (expense) benefit	4,107	(4,372)	15,897	6,703
Income tax (expense) benefit related to items of other comprehensive income (loss)	(1,438)	1,530	(5,564)	(2,344)
Total other comprehensive income (loss)	2,669	(2,842)	10,333	4,359
Comprehensive Income	$ 14,676	$ 10,605	$ 34,813	$ 32,027

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2014	$ 716,145	$ 105,563	$ 365,615	$ 353,027	$ (4,499)	$ (103,561)
Beginning balance, shares at Dec. 31, 2014		91,723,028
Net Income	27,668			27,668
Other comprehensive income (loss)	4,359				4,359
Dividends, declared (USD per share)	(12,635)			(12,635)
Treasury stock acquired	(25,383)					(25,383)
Treasury stock acquired, shares		(2,918,066)
Restricted stock	860	$ 0	286	0		574
Restricted stock, shares		134,370
Ending balance at Jun. 30, 2015	711,206	$ 105,563	365,933	368,060	(140)	(128,210)
Ending balance, shares at Jun. 30, 2015		88,960,268
Stock Issued During Period, Shares, Treasury Stock Reissued		20,936
Stock Issued During Period, Value, Treasury Stock Reissued	192		32	0		160
Beginning balance at Dec. 31, 2015	$ 719,546	$ 105,563	365,981	378,081	(2,386)	(127,693)
Beginning balance, shares at Dec. 31, 2015	88,961,268	88,961,268
Net Income	$ 24,480			24,480
Other comprehensive income (loss)	10,333				10,333
Dividends, declared (USD per share)	(12,451)			(12,451)
Treasury stock acquired	(902)					(902)
Treasury stock acquired, shares		(97,769)
Restricted stock	564	$ 0	161	0		403
Restricted stock, shares		63,348
Ending balance at Jun. 30, 2016	$ 741,786	$ 105,563	366,181	390,110	$ 7,947	(128,015)
Ending balance, shares at Jun. 30, 2016	88,959,315	88,949,995
Stock Issued During Period, Shares, Treasury Stock Reissued		23,148
Stock Issued During Period, Value, Treasury Stock Reissued	$ 216		$ 39	$ 0		$ 177

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Stockholders' Equity [Abstract]
Cash Dividends Declared per Common Share (in dollars per share)	$ 0.07	$ 0.07	$ 0.14	$ 0.14

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities
Net Income	$ 24,480	$ 27,668
Provision for credit losses	16,898	4,197
Deferred tax expense	1,909	7,102
Depreciation and amortization	3,481	3,802
Net gains on securities and other assets	(372)	(235)
Net amortization of premiums and discounts on securities	2,264	1,151
Income from increase in cash surrender value of bank owned life insurance	(2,607)	(2,732)
(Increase) decrease in interest receivable	(315)	74
Mortgage loans originated for sale	(56,139)	(39,941)
Proceeds from sale of mortgage loans	55,251	36,079
Decrease in interest payable	(84)	(200)
(Decrease) increase in income taxes payable	(2,534)	503
Other-net	(4,758)	(14,817)
Net cash provided by operating activities	37,474	22,651
Investing Activities
Proceeds from sale and maturity of held-to-maturity securities	18,601	1,115
Payments to acquire held-to-maturity securities	(40,161)	(131,145)
Proceeds from Sale of Available-for-sale Securities	55,744	0
Proceeds from maturities and redemptions of available-for-sale securities	82,527	235,971
Purchases of available-for-sale securities	(94,777)	(10,800)
Purchases of FHLB stock	(20,324)	(29,251)
Proceeds from the redemption of FHLB stock	25,189	20,449
Proceeds from bank owned life insurance	0	294
Proceeds from Sale of Loans Receivable	213	102
Proceeds from sale of other assets	3,621	2,282
Net increase in loans	(173,817)	(48,785)
Payments for Purchase of Other Assets	(204)	0
Purchases of premises and equipment	(4,201)	(2,521)
Net cash (used in) provided by investing activities	(147,589)	37,711
Financing Activities
Net (decrease) increase in federal funds purchased	(4,000)	15,000
Net (decrease) increase in other short-term borrowings	(42,138)	111,041
Net increase (decrease) in deposits	198,838	(105,404)
Repayments of other long-term debt	(280)	(50,270)
Dividends paid	(12,451)	(12,635)
Proceeds from Sale of Treasury Stock	216	192
Purchase of treasury stock	(902)	(25,383)
Net cash provided by (used in) financing activities	139,283	(67,459)
Net increase (decrease) in cash and cash equivalents	29,168	(7,097)
Cash and cash equivalents at January 1	69,452	74,538
Cash and cash equivalents at June 30	$ 98,620	$ 67,441

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accounting and reporting policies of First Commonwealth Financial Corporation and its subsidiaries (“First Commonwealth” or the “Company”) conform with generally accepted accounting principles in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates, assumptions and judgments that affect the amounts reported in the financial statements and accompanying notes. Actual realized amounts could differ from those estimates. In the opinion of management, the unaudited interim condensed consolidated financial statements include all adjustments (consisting of only normal recurring adjustments) necessary for a fair presentation of First Commonwealth’s financial position, results of operations, comprehensive income, cash flows and changes in shareholders’ equity as of and for the periods presented. The results of operations for the six months ended June 30, 2016 are not necessarily indicative of the results that may be expected for the full year of 2016 . These interim financial statements should be read in conjunction with First Commonwealth’s 2015 Annual Report on Form 10-K. For purposes of reporting cash flows, cash and cash equivalents include cash on hand, amounts due from banks, federal funds sold and interest-bearing bank deposits. Generally, federal funds are sold for one-day periods.

Supplemental Comprehensive Inco

Supplemental Comprehensive Income Disclosures	6 Months Ended
	Jun. 30, 2016
Supplemental Comprehensive Income Disclosures [Abstract]
Supplemental Comprehensive Income Disclosures	Supplemental Comprehensive Income Disclosures The following table identifies the related tax effects allocated to each component of other comprehensive income (“OCI”) in the Condensed Consolidated Statements of Comprehensive Income. Reclassification adjustments related to securities available for sale are included in the "Net securities gains" line and reclassification adjustments related to losses on derivatives are included in the "Other operating expenses" line in the Condensed Consolidated Statements of Income. For the Six Months Ended June 30, 2016 2015 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains on securities: Unrealized holding gains on securities arising during the period $ 13,872 $ (4,855 ) $ 9,017 $ 6,166 $ (2,156 ) $ 4,010 Reclassification adjustment for gains on securities included in net income (28 ) 10 (18 ) (125 ) 44 (81 ) Total unrealized gains on securities 13,844 (4,845 ) 8,999 6,041 (2,112 ) 3,929 Unrealized gains on derivatives: Unrealized holding gains on derivatives arising during the period 2,094 (733 ) 1,361 668 (234 ) 434 Reclassification adjustment for gains on derivatives included in net income (41 ) 14 (27 ) (6 ) 2 (4 ) Total unrealized gains on derivatives 2,053 (719 ) 1,334 662 (232 ) 430 Total other comprehensive income $ 15,897 $ (5,564 ) $ 10,333 $ 6,703 $ (2,344 ) $ 4,359 For the Three Months Ended June 30, 2016 2015 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains (losses) on securities: Unrealized holding gains (losses) on securities arising during the period $ 3,802 $ (1,331 ) $ 2,471 $ (3,814 ) $ 1,335 $ (2,479 ) Reclassification adjustment for gains on securities included in net income (28 ) 10 (18 ) (20 ) 7 (13 ) Total unrealized gains (losses) on securities 3,774 (1,321 ) 2,453 (3,834 ) 1,342 (2,492 ) Unrealized gains (losses) on derivatives: Unrealized holding gains (losses) on derivatives arising during the period 359 (126 ) 233 (527 ) 184 (343 ) Reclassification adjustment for gains on derivatives included in net income (26 ) 9 (17 ) (11 ) 4 (7 ) Total unrealized gains (losses) on derivatives 333 (117 ) 216 (538 ) 188 (350 ) Total other comprehensive income (loss) $ 4,107 $ (1,438 ) $ 2,669 $ (4,372 ) $ 1,530 $ (2,842 ) The following table details the change in components of OCI for the six months ended June 30 : 2016 2015 Securities Available for Sale Post-Retirement Obligation Derivatives Accumulated Other Comprehensive Income Securities Available for Sale Post-Retirement Obligation Derivatives Accumulated Other Comprehensive Income (dollars in thousands) Balance at December 31 $ (2,956 ) $ 10 $ 560 $ (2,386 ) $ (4,875 ) $ 76 $ 300 $ (4,499 ) Other comprehensive income before reclassification adjustment 9,017 — 1,361 10,378 4,010 — 434 4,444 Amounts reclassified from accumulated other comprehensive (loss) income (18 ) — (27 ) (45 ) (81 ) — (4 ) (85 ) Net other comprehensive income during the period 8,999 — 1,334 10,333 3,929 — 430 4,359 Balance at June 30 $ 6,043 $ 10 $ 1,894 $ 7,947 $ (946 ) $ 76 $ 730 $ (140 )

Supplemental Cash Flow Disclosu

Supplemental Cash Flow Disclosures	6 Months Ended
	Jun. 30, 2016
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Disclosures	Supplemental Cash Flow Disclosures The following table presents information related to cash paid during the period for interest, as well as detail on non-cash investing and financing activities for the six months ended June 30 : 2016 2015 (dollars in thousands) Cash paid during the period for: Interest $ 9,583 $ 7,893 Income taxes 10,500 4,000 Non-cash investing and financing activities: Loans transferred to other real estate owned and repossessed assets 2,632 2,315 Loans transferred from held to maturity to held for sale 3,573 3,071 Gross increase in market value adjustment to securities available for sale 13,845 6,036 Gross increase in market value adjustment to derivatives 2,053 662 Investments committed to purchase, not settled 1,946 1,817 Proceeds from death benefit on bank-owned life insurance not received 523 —

Earnings per Share

Earnings per Share	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share The following table summarizes the composition of the weighted-average common shares (denominator) used in the basic and diluted earnings per share computations: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 Weighted average common shares issued 105,563,455 105,563,455 105,563,455 105,563,455 Average treasury stock shares (16,620,341 ) (16,445,760 ) (16,621,717 ) (15,480,232 ) Average unearned nonvested shares (111,356 ) (195,303 ) (105,815 ) (189,561 ) Weighted average common shares and common stock equivalents used to calculate basic earnings per share 88,831,758 88,922,392 88,835,923 89,893,662 Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share 6,856 16,611 4,760 9,888 Weighted average common shares and common stock equivalents used to calculate diluted earnings per share 88,838,614 88,939,003 88,840,683 89,903,550 The following table shows the number of shares and the price per share related to common stock equivalents that were not included in the computation of diluted earnings per share for the six months ended June 30 because to do so would have been antidilutive. 2016 2015 Price Range Price Range Shares From To Shares From To Restricted Stock 81,887 7.57 9.84 146,933 5.26 9.26

Commitments and Contingent Liab

Commitments and Contingent Liabilities	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities Commitments and Letters of Credit Standby letters of credit and commercial letters of credit are conditional commitments issued by First Commonwealth to guarantee the performance of a customer to a third party. The contract or notional amount of these instruments reflects the maximum amount of future payments that First Commonwealth could be required to pay under the guarantees if there were a total default by the guaranteed parties, without consideration of possible recoveries under recourse provisions or from collateral held or pledged. In addition, many of these commitments are expected to expire without being drawn upon; therefore, the total commitment amounts do not necessarily represent future cash requirements. The following table identifies the notional amount of those instruments at: June 30, 2016 December 31, 2015 (dollars in thousands) Financial instruments whose contract amounts represent credit risk: Commitments to extend credit $ 1,616,286 $ 1,643,187 Financial standby letters of credit 19,256 17,843 Performance standby letters of credit 28,067 26,497 Commercial letters of credit 1,615 1,672 The notional amounts outstanding as of June 30, 2016 include amounts issued in 2016 of $13 thousand in financial standby letters of credit, $2.3 million in performance standby letters of credit and $0.2 million commercial letters of credit. A liability of $0.2 million has been recorded as of both June 30, 2016 and December 31, 2015 which represents the estimated fair value of letters of credit issued. The fair value of letters of credit is estimated based on the unrecognized portion of fees received at the time the commitment was issued. Unused commitments and letters of credit provide exposure to future credit loss in the event of nonperformance by the borrower or guaranteed parties. Management’s evaluation of the credit risk related to these commitments resulted in the recording of a liability of $3.5 million as of June 30, 2016 and $4.4 million as of December 31, 2015 . This liability is reflected in "Other liabilities" in the Condensed Consolidated Statements of Financial Condition. The credit risk evaluation incorporated probability of default, loss given default and estimated utilization for the next twelve months for each loan category and the letters of credit. Legal Proceedings First Commonwealth and its subsidiaries are subject in the normal course of business to various pending and threatened legal proceedings in which claims for monetary damages are asserted. As of June 30, 2016, management, after consultation with legal counsel, does not anticipate that the aggregate ultimate liability arising out of litigation pending or threatened against First Commonwealth or its subsidiaries will be material to First Commonwealth’s consolidated financial position. On at least a quarterly basis, First Commonwealth assesses its liabilities and contingencies in connection with such legal proceedings. For those matters where it is probable that First Commonwealth will incur losses and the amounts of the losses can be reasonably estimated, First Commonwealth records an expense and corresponding liability in its consolidated financial statements. To the extent the pending or threatened litigation could result in exposure in excess of that liability, the amount of such excess is not currently estimable. Although not considered probable, the range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability (if any), is between $0 and $7 million . Although First Commonwealth does not believe that the outcome of pending litigation will be material to First Commonwealth’s consolidated financial position, it cannot rule out the possibility that such outcomes will be material to the consolidated results of operations and cash flows for a particular reporting period in the future. First Commonwealth Financial Corporation and First Commonwealth Bank were named defendants in an action commenced August 27, 2015 by eight named plaintiffs that is pending in the Court of Common Pleas of Jefferson County, Pennsylvania. The plaintiffs allege that the Bank repossessed motor vehicles, sold the vehicles and sought to collect deficiency balances in a manner that did not comply with the notice requirements of the Pennsylvania Uniform Commercial Code (UCC), charged inappropriate costs and fees, including storage costs for dates that a repossessed vehicle was not in storage, and wrongly filed forms with the Department of Motor Vehicles asserting that the Bank had complied with applicable laws relating to the repossession of the vehicles. The plaintiffs seek to pursue the action as a class action on behalf of the named plaintiffs and other similarly situated plaintiffs who had their automobiles repossessed and seek to recover damages under the UCC and the Pennsylvania Fair Credit Extension Uniformity Act. First Commonwealth and the Bank contest the plaintiffs’ allegations and intend to oppose class certification. The Bank has also asserted counterclaims for breach of contract, set-off and recoupment against the plaintiffs, individually, and as representatives of the putative class. The Bank and counsel for the plaintiffs reached an agreement-in-principle to settle the litigation during the second quarter. The parties are negotiating the terms of a definitive settlement agreement which would be subject to court approval and other customary conditions. The estimated cost of the settlement to the Bank was recorded as a liability as of June 30, 2016. As set forth in the preceding paragraph, all current litigation matters, including this action, are believed to be within the range of reasonably possible losses set forth in the preceding paragraph.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2016
Investment Securities [Abstract]
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	Investment Securities Securities Available for Sale Below is an analysis of the amortized cost and estimated fair values of securities available for sale at: June 30, 2016 December 31, 2015 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 16,730 $ 2,032 $ — $ 18,762 $ 20,034 $ 2,071 $ (13 ) $ 22,092 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 732,618 15,012 (234 ) 747,396 778,476 7,983 (8,882 ) 777,577 Mortgage-Backed Securities – Commercial 2 — — 2 28 — — 28 Other Government-Sponsored Enterprises 19,300 22 — 19,322 19,201 2 (85 ) 19,118 Obligations of States and Political Subdivisions 27,071 965 — 28,036 27,066 532 — 27,598 Corporate Securities 5,898 524 — 6,422 1,897 422 — 2,319 Pooled Trust Preferred Collateralized Debt Obligations 42,750 500 (9,527 ) 33,723 42,239 916 (7,497 ) 35,658 Total Debt Securities 844,369 19,055 (9,761 ) 853,663 888,941 11,926 (16,477 ) 884,390 Equities 1,670 — — 1,670 2,170 — — 2,170 Total Securities Available for Sale $ 846,039 $ 19,055 $ (9,761 ) $ 855,333 $ 891,111 $ 11,926 $ (16,477 ) $ 886,560 Mortgage backed securities include mortgage backed obligations of U.S. Government agencies and obligations of U.S. Government-sponsored enterprises. These obligations have contractual maturities ranging from less than one year to approximately 30 years with lower anticipated lives to maturity due to prepayments. All mortgage backed securities contain a certain amount of risk related to the uncertainty of prepayments of the underlying mortgages. Interest rate changes have a direct impact upon prepayment speeds; therefore, First Commonwealth uses computer simulation models to test the average life and yield volatility of all mortgage backed securities under various interest rate scenarios to monitor the potential impact on earnings and interest rate risk positions. Expected maturities will differ from contractual maturities because issuers may have the right to call or repay obligations with or without call or prepayment penalties. Other fixed income securities within the portfolio also contain prepayment risk. The amortized cost and estimated fair value of debt securities available for sale at June 30, 2016 , by contractual maturity, are shown below. Amortized Estimated (dollars in thousands) Due within 1 year $ 2,601 $ 2,602 Due after 1 but within 5 years 20,696 20,780 Due after 5 but within 10 years 27,070 28,036 Due after 10 years 44,652 36,085 95,019 87,503 Mortgage-Backed Securities (a) 749,350 766,160 Total Debt Securities $ 844,369 $ 853,663 (a) Mortgage Backed Securities include an amortized cost of $16.7 million and a fair value of $18.8 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $732.6 million and a fair value of $747.4 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac. Proceeds from sales, gross gains (losses) realized on sales, maturities and other-than-temporary impairment charges related to securities available for sale were as follows for the six months ended June 30 : 2016 2015 (dollars in thousands) Proceeds from sales $ 55,744 $ — Gross gains (losses) realized: Sales Transactions: Gross gains $ 304 $ — Gross losses (276 ) — 28 — Maturities and impairment Gross gains — 105 Gross losses — — Other-than-temporary impairment — — — 105 Net gains and impairment $ 28 $ 105 Securities available for sale with an estimated fair value of $475.9 million and $416.1 million were pledged as of June 30, 2016 and December 31, 2015 , respectively, to secure public deposits and for other purposes required or permitted by law. Securities Held to Maturity Below is an analysis of the amortized cost and fair values of debt securities held to maturity at: June 30, 2016 December 31, 2015 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 4,712 $ 146 $ — $ 4,858 $ 4,775 $ — $ (7 ) $ 4,768 Mortgage-Backed Securities- Commercial 36,529 403 — 36,932 16,843 — (247 ) 16,596 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 313,987 6,746 — 320,733 315,609 30 (1,824 ) 313,815 Mortgage-Backed Securities – Commercial 14,940 460 — 15,400 15,187 — (178 ) 15,009 Obligations of States and Political Subdivisions 35,808 1,039 — 36,847 31,910 301 (58 ) 32,153 Total Securities Held to Maturity $ 405,976 $ 8,794 $ — $ 414,770 $ 384,324 $ 331 $ (2,314 ) $ 382,341 The amortized cost and estimated fair value of debt securities held to maturity at June 30, 2016 , by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Amortized Estimated (dollars in thousands) Due within 1 year $ — $ — Due after 1 but within 5 years 1,231 1,265 Due after 5 but within 10 years 28,052 28,940 Due after 10 years 6,525 6,642 35,808 36,847 Mortgage-Backed Securities (a) 370,168 377,923 Total Debt Securities $ 405,976 $ 414,770 (a) Mortgage Backed Securities include an amortized cost of $41.2 million and a fair value of $41.8 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $328.9 million and a fair value of $336.1 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac. Securities held to maturity with an amortized cost of $291.5 million and $45.7 million were pledged as of June 30, 2016 and December 31, 2015 , respectively, to secure public deposits and for other purposes required or permitted by law.

Impairment of Investment Securi

Impairment of Investment Securities	6 Months Ended
	Jun. 30, 2016
Impairment of Investment Securities Disclosure [Abstract]
Impairment of Investment Securities	Impairment of Investment Securities Securities Available for Sale and Held to Maturity As required by FASB ASC Topic 320, “Investments – Debt and Equity Securities,” credit-related other-than-temporary impairment on debt securities is recognized in earnings, while non-credit related other-than-temporary impairment on debt securities not expected to be sold is recognized in OCI. During the six months ended June 30, 2016 and 2015 , no other-than-temporary impairment charges were recognized. First Commonwealth utilizes the specific identification method to determine the net gain or loss on debt securities and the average cost method to determine the net gain or loss on equity securities. We review our investment portfolio on a quarterly basis for indications of impairment. This review includes analyzing the length of time and the extent to which the fair value has been lower than the cost, the financial condition and near-term prospects of the issuer, including any specific events which may influence the operations of the issuer and whether we are more likely than not to sell, or be required to sell, the security. We evaluate whether we are more likely than not to sell debt securities based upon our investment strategy for the particular type of security and our cash flow needs, liquidity position, capital adequacy, tax position and interest rate risk position. In addition, the risk of future other-than-temporary impairment may be influenced by additional bank failures, weakness in the U.S. economy, changes in real estate values and additional interest deferrals in our pooled trust preferred collateralized debt obligations. Our pooled trust preferred collateralized debt obligations are beneficial interests in securitized financial assets within the scope of FASB ASC Topic 325, “Investments – Other,” and are therefore evaluated for other-than-temporary impairment using management’s best estimate of future cash flows. If these estimated cash flows indicate that it is probable that an adverse change in cash flows has occurred, then other-than-temporary impairment would be recognized in accordance with FASB ASC Topic 320. There is a risk that First Commonwealth will record other-than-temporary impairment charges in the future. See Note 10, “Fair Values of Assets and Liabilities,” for additional information. The following table presents the gross unrealized losses and estimated fair values at June 30, 2016 for both available for sale and held to maturity securities by investment category and time frame for which securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential $ 15,227 $ (13 ) $ 64,716 $ (221 ) $ 79,943 $ (234 ) Pooled Trust Preferred Collateralized Debt Obligations — — 28,276 (9,527 ) 28,276 (9,527 ) Total Securities $ 15,227 $ (13 ) $ 92,992 $ (9,748 ) $ 108,219 $ (9,761 ) At June 30, 2016 , fixed income securities issued by U.S. Government-sponsored enterprises comprised 2% of total unrealized losses due to changes in market interest rates. Pooled trust preferred collateralized debt obligations accounted for 98% of the unrealized losses primarily due to the illiquid market for this investment type. At June 30, 2016 , there are 19 debt securities in an unrealized loss position. The following table presents the gross unrealized losses and estimated fair values at December 31, 2015 by investment category and time frame for which securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 6,798 $ (20 ) $ — $ — $ 6,798 $ (20 ) Mortgage-Backed Securities - Commercial 16,596 (247 ) — — 16,596 (247 ) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 436,011 (3,293 ) 263,119 (7,413 ) 699,130 (10,706 ) Mortgage-Backed Securities – Commercial 15,009 (178 ) — — 15,009 (178 ) Other Government-Sponsored Enterprises 12,316 (85 ) — — 12,316 (85 ) Obligation of States and Political Subdivisions 7,208 (58 ) — — 7,208 (58 ) Pooled Trust Preferred Collateralized Debt Obligations — — 29,957 (7,497 ) 29,957 (7,497 ) Total Securities $ 493,938 $ (3,881 ) $ 293,076 $ (14,910 ) $ 787,014 $ (18,791 ) As of June 30, 2016 , our corporate securities had an amortized cost and an estimated fair value of $5.9 million and $6.4 million , respectively. As of December 31, 2015 , our corporate securities had an amortized cost and estimated fair value of $1.9 million and $2.3 million , respectively. Corporate securities are comprised of debt for large regional banks. There were no corporate securities in an unrealized loss position as of June 30, 2016 and December 31, 2015 . When unrealized losses exist on these investments, management reviews each of the issuer’s asset quality, earnings trends and capital position, to determine whether issues in an unrealized loss position were other-than-temporarily impaired. All interest payments on the corporate securities are being made as contractually required. As of June 30, 2016 , the book value of our pooled trust preferred collateralized debt obligations totaled $42.8 million with an estimated fair value of $33.7 million , which includes securities comprised of 274 banks and other financial institutions. All of our pooled securities are mezzanine tranches, three of which have no senior class remaining in the issue. The credit ratings on all of our issues are below investment grade. At the time of initial issue, the subordinated tranches ranged in size from approximately 7% to 35% of the total principal amount of the respective securities and no more than 5% of any pooled security consisted of a security issued by any one institution. As of June 30, 2016 , after taking into account management’s best estimates of future interest deferrals and defaults, three of our securities had no excess subordination in the tranches we own and six of our securities had excess subordination which ranged from 2% to 82% of the current performing collateral. The following table provides information related to our pooled trust preferred collateralized debt obligations as of June 30, 2016 : Deal Class Book Estimated Fair Unrealized Moody’s/ Number Deferrals Excess (dollars in thousands) Pre TSL IV Mezzanine $ 1,830 $ 1,301 $ (529 ) B1/BB 6 18.05 % 58.51 % Pre TSL VII Mezzanine 3,061 3,324 263 Ca/- 14 49.68 — Pre TSL VIII Mezzanine 2,042 1,691 (351 ) C/C 28 53.00 — Pre TSL IX Mezzanine 2,394 1,797 (597 ) B1/C 38 29.80 9.73 Pre TSL X Mezzanine 1,675 1,817 142 Caa1/C 43 32.22 2.20 Pre TSL XII Mezzanine 5,786 4,442 (1,344 ) B3/C 66 22.03 — Pre TSL XIII Mezzanine 12,828 9,971 (2,857 ) Ba3/C 56 11.34 47.86 Pre TSL XIV Mezzanine 12,924 9,075 (3,849 ) B1/CC 56 15.21 38.08 MMCap I Mezzanine 210 305 95 Ca/C 8 58.11 81.96 Total $ 42,750 $ 33,723 $ (9,027 ) Lack of liquidity in the market for trust preferred collateralized debt obligations, below investment grade credit ratings and market uncertainties related to the financial industry are factors contributing to the impairment on these securities. All of the Company's pooled trust preferred securities are included in the non-exclusive list issued by the regulatory agencies and therefore are not considered covered funds under the Volcker Rule. On a quarterly basis we evaluate our debt securities for other-than-temporary impairment. During the three and six months ended June 30, 2016 and 2015 , there were no credit-related other-than-temporary impairment charges recognized on our pooled trust preferred collateralized debt obligations. When evaluating these investments, we determine a credit-related portion and a non-credit related portion of other-than-temporary impairment. The credit-related portion is recognized in earnings and represents the difference between book value and the present value of future cash flows. The non-credit related portion is recognized in OCI and represents the difference between the fair value of the security and the amount of credit-related impairment. A discounted cash flow analysis provides the best estimate of credit-related other-than-temporary impairment for these securities. Additional information related to the discounted cash flow analysis follows: Our pooled trust preferred collateralized debt obligations are measured for other-than-temporary impairment within the scope of FASB ASC Topic 325 by determining whether it is probable that an adverse change in estimated cash flows has occurred. Determining whether there has been an adverse change in estimated cash flows from the cash flows previously projected involves comparing the present value of remaining cash flows previously projected against the present value of the cash flows estimated at June 30, 2016 . We consider the discounted cash flow analysis to be our primary evidence when determining whether credit related other-than-temporary impairment exists. Results of a discounted cash flow test are significantly affected by other variables, such as the estimate of future cash flows, credit worthiness of the underlying banks and determination of probability of default of the underlying collateral. The following provides additional information for each of these variables: • Estimate of Future Cash Flows – Cash flows are constructed in an INTEX cash flow model which includes each deal’s structural features. Projected cash flows include prepayment assumptions, which are dependent on the issuer's asset size and coupon rate. For collateral issued by financial institutions over $15 billion in asset size with a coupon over 7% , a 100% prepayment rate is assumed. Financial institutions over $15 billion with a coupon of 7% or under are assigned a prepayment rate of 40% for two years and 2% thereafter. Financial institutions with assets between $2 billion and $15 billion with coupons over 7% are assigned a 5% prepayment rate. For financial institutions below $2 billion , if the coupon is over 10% , a prepayment rate of 5% is assumed and for all other issuers, there is no prepayment assumption incorporated into the cash flows. The modeled cash flows are then used to estimate if all the scheduled principal and interest payments of our investments will be returned. • Credit Analysis – A quarterly credit evaluation is performed for each of the 274 banks comprising the collateral across the various pooled trust preferred securities. Our credit evaluation considers all evidence available to us and includes the nature of the issuer’s business, its years of operating history, corporate structure, loan composition, loan concentrations, deposit mix, asset growth rates, geographic footprint and local economic environment. Our analysis focuses on profitability, return on assets, shareholders’ equity, net interest margin, credit quality ratios, operating efficiency, capital adequacy and liquidity. • Probability of Default – A probability of default is determined for each bank and is used to calculate the expected impact of future deferrals and defaults on our expected cash flows. Each bank in the collateral pool is assigned a probability of default for each year until maturity. Currently, any bank that is in default is assigned a 100% probability of default and a 0% projected recovery rate. All other banks in the pool are assigned a probability of default based on their unique credit characteristics and market indicators with a 10% projected recovery rate. For the majority of banks currently in deferral we assume the bank continues to defer and will eventually default and, therefore, a 100% probability of default is assigned. However, for some deferring collateral there is the possibility that they will become current on interest or principal payments at some point in the future and in those cases a probability that the deferral will ultimately cure is assigned. The probability of default is updated quarterly. As of June 30, 2016 , default probabilities for performing collateral ranged from 0.33% to 75% . Our credit evaluation provides a basis for determining deferral and default probabilities for each underlying piece of collateral. Using the results of the credit evaluation, the next step of the process is to look at pricing of senior debt or credit default swaps for the issuer (or where such information is unavailable, for companies having similar credit profiles as the issuer). The pricing of these market indicators provides the information necessary to determine appropriate default probabilities for each bank. In addition to the above factors, our evaluation of impairment also includes a stress test analysis which provides an estimate of excess subordination for each tranche. We stress the cash flows of each pool by increasing current default assumptions to the level of defaults that results in an adverse change in estimated cash flows. This stressed breakpoint is then used to calculate excess subordination levels for each pooled trust preferred security. The results of the stress test allow management to identify those pools that are at a greater risk for a future break in cash flows so that we can monitor banks in those pools more closely for potential deterioration of credit quality. Our cash flow analysis as of June 30, 2016 , indicates that no credit-related other-than-temporary impairment has occurred on our pooled trust preferred securities during the six months ended June 30, 2016 . Based upon the analysis performed by management, it is probable that three of our pooled trust preferred securities will experience principal and interest shortfalls and therefore appropriate other-than-temporary charges were recorded in prior periods. These securities are identified in the table on page 15 with 0% “Excess Subordination as a Percentage of Current Performing Collateral.” For the remaining securities listed in that table, our analysis as of June 30, 2016 indicates it is probable that we will collect all contractual principal and interest payments. For four of those securities, PreTSL IX, PreTSL XIII, PreTSL XIV and MMCap I, other-than-temporary impairment charges were recorded in prior periods; however, due to improvement in the expected cash flows of these securities, it is now probable that all contractual payments will be received. During 2008, 2009 and 2010, other-than-temporary impairment charges were recognized on all of our pooled trust preferred securities, except for PreTSL IV. Our cash flow analysis as of June 30, 2016 , for all of these impaired securities indicates that it is now probable we will collect principal and interest in excess of what was estimated at the time other-than-temporary impairment charges were recorded. This change can be attributed to improvement in the underlying collateral for these securities and has resulted in the present value of estimated future principal and interest payments exceeding the securities' current book value. The excess for each bond of the present value of future cash flows over our current book value ranges from 20% to 127% and will be recognized as an adjustment to yield over the remaining life of these securities. The excess subordination recognized as an adjustment to yield is reflected in the following table as increases in cash flows expected to be collected. The following table provides a cumulative roll forward of credit losses recognized in earnings for debt securities held and not intended to be sold: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 (dollars in thousands) Balance, beginning (a) $ 24,590 $ 25,707 $ 24,851 $ 26,246 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — — — Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — — — Increases in cash flows expected to be collected, recognized over the remaining life of the security (b) (280 ) (341 ) (541 ) (662 ) Reduction for debt securities called during the period — — — (218 ) Balance, ending $ 24,310 $ 25,366 $ 24,310 $ 25,366 (a) The beginning balance represents credit related losses included in other-than-temporary impairment charges recognized on debt securities in prior periods. (b) Represents the increase in cash flows recognized in interest income during the period. In the first six months of 2016 and 2015 , no other-than-temporary impairment charges were recorded on equity securities. On a quarterly basis, management evaluates equity securities for other-than-temporary impairment by reviewing the severity and duration of decline in estimated fair value, research reports, analysts’ recommendations, credit rating changes, news stories, annual reports, regulatory filings, impact of interest rate changes and other relevant information. As of June 30, 2016 and 2015 , there were no equity securities in an unrealized loss position. Other Investments As a member of the Federal Home Loan Bank ("FHLB"), First Commonwealth is required to purchase and hold stock in the FHLB to satisfy membership and borrowing requirements. The level of stock required to be held is dependent on the amount of First Commonwealth's mortgage-related assets and outstanding borrowings with the FHLB. This stock is restricted in that it can only be sold to the FHLB or to another member institution, and all sales of FHLB stock must be at par. As a result of these restrictions, FHLB stock is unlike other investment securities insofar as there is no trading market for FHLB stock and the transfer price is determined by FHLB membership rules and not by market participants. As of June 30, 2016 and December 31, 2015 , our FHLB stock totaled $58.1 million and $63.0 million , respectively, and is included in “Other investments” on the Condensed Consolidated Statements of Financial Condition. FHLB stock is held as a long-term investment and its value is determined based on the ultimate recoverability of the par value. First Commonwealth evaluates impairment quarterly and has concluded that the par value of its investment in FHLB stock will be recovered. Accordingly, no impairment charge was recorded on these securities during the three and six months ended June 30, 2016 .

Loans and Allowance for Credit

Loans and Allowance for Credit Losses	6 Months Ended
	Jun. 30, 2016
Loans and Leases Receivable Disclosure [Abstract]
Loans and Allowance for Credit Losses	Loans and Allowance for Credit Losses The following table provides outstanding balances related to each of our loan types: June 30, 2016 December 31, 2015 (dollars in thousands) Commercial, financial, agricultural and other $ 1,185,062 $ 1,150,906 Real estate construction 242,132 220,736 Residential real estate 1,199,005 1,224,465 Commercial real estate 1,648,222 1,479,000 Loans to individuals 569,355 608,643 Total loans $ 4,843,776 $ 4,683,750 Credit Quality Information As part of the on-going monitoring of credit quality within the loan portfolio, the following credit worthiness categories are used in grading our loans: Pass Acceptable levels of risk exist in the relationship. Includes all loans not classified as OAEM, substandard or doubtful. Other Assets Especially Mentioned (OAEM) Potential weaknesses that deserve management’s close attention. The potential weaknesses may result in deterioration of the repayment prospects or weaken the Company’s credit position at some future date. The credit risk may be relatively minor, yet constitute an undesirable risk in light of the circumstances surrounding the specific credit. No loss of principal or interest is expected. Substandard Well-defined weakness or a weakness that jeopardizes the repayment of the debt. A loan may be classified as substandard as a result of deterioration of the borrower’s financial condition and repayment capacity. Loans for which repayment plans have not been met or collateral equity margins do not protect the Company may also be classified as substandard. Doubtful Loans with the characteristics of substandard loans with the added characteristic that collection or liquidation in full, on the basis of presently existing facts and conditions, is highly improbable. The use of creditworthiness categories to grade loans permits management’s use of migration analysis to estimate a portion of credit risk. The Company’s internal creditworthiness grading system provides a measurement of credit risk based primarily on an evaluation of the borrower’s cash flow and collateral. Movement between these rating categories provides a predictive measure of credit losses and therefore assists in determining the appropriate level for the loan loss reserves. Category ratings are reviewed each quarter, at which time management analyzes the results, as well as other external statistics and factors related to loan performance. Loans that migrate towards higher risk rating levels generally have an increased risk of default, whereas loans that migrate toward lower risk ratings generally will result in a lower risk factor being applied to those related loan balances. The following tables represent our credit risk profile by creditworthiness: June 30, 2016 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 1,095,516 $ 241,840 $ 1,183,847 $ 1,625,206 $ 569,087 $ 4,715,496 Non-Pass OAEM 11,923 292 6,846 7,221 — 26,282 Substandard 77,623 — 8,312 15,795 268 101,998 Doubtful — — — — — — Total Non-Pass 89,546 292 15,158 23,016 268 128,280 Total $ 1,185,062 $ 242,132 $ 1,199,005 $ 1,648,222 $ 569,355 $ 4,843,776 December 31, 2015 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 1,074,858 $ 220,267 $ 1,209,606 $ 1,436,714 $ 608,342 $ 4,549,787 Non-Pass OAEM 11,825 442 5,244 30,012 — 47,523 Substandard 64,223 27 9,615 12,274 301 86,440 Doubtful — — — — — — Total Non-Pass 76,048 469 14,859 42,286 301 133,963 Total $ 1,150,906 $ 220,736 $ 1,224,465 $ 1,479,000 $ 608,643 $ 4,683,750 Portfolio Risks The credit quality of our loan portfolio can potentially represent significant risk to our earnings, capital, regulatory agency relationships, investment community reputation and shareholder returns. First Commonwealth devotes a substantial amount of resources managing this risk primarily through our credit administration department that develops and administers policies and procedures for underwriting, maintaining, monitoring and collecting activities. Credit administration is independent of lending departments and oversight is provided by the credit committee of the First Commonwealth Board of Directors. Criticized loans have been evaluated when determining the appropriateness of the allowance for credit losses, which we believe is adequate to absorb losses inherent to the portfolio as of June 30, 2016 . However, changes in economic conditions, interest rates, borrower financial condition, delinquency trends or previously established fair values of collateral factors could significantly change those judgmental estimates. Age Analysis of Past Due Loans by Segment The following tables delineate the aging analysis of the recorded investments in past due loans as of June 30, 2016 and December 31, 2015 . Also included in these tables are loans that are 90 days or more past due and still accruing because they are well-secured and in the process of collection. June 30, 2016 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 2,344 $ 714 $ 283 $ 37,429 $ 40,770 $ 1,144,292 $ 1,185,062 Real estate construction — — — — — 242,132 242,132 Residential real estate 4,544 1,542 243 6,448 12,777 1,186,228 1,199,005 Commercial real estate 1,166 — 1 3,931 5,098 1,643,124 1,648,222 Loans to individuals 2,072 700 857 268 3,897 565,458 569,355 Total $ 10,126 $ 2,956 $ 1,384 $ 48,076 $ 62,542 $ 4,781,234 $ 4,843,776 December 31, 2015 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 364 $ 49 $ 129 $ 23,653 $ 24,195 $ 1,126,711 $ 1,150,906 Real estate construction 280 — — 28 308 220,428 220,736 Residential real estate 4,175 1,055 1,315 6,500 13,045 1,211,420 1,224,465 Commercial real estate 781 — 65 6,223 7,069 1,471,931 1,479,000 Loans to individuals 2,998 774 946 301 5,019 603,624 608,643 Total $ 8,598 $ 1,878 $ 2,455 $ 36,705 $ 49,636 $ 4,634,114 $ 4,683,750 Nonaccrual Loans The previous tables summarize nonaccrual loans by loan segment. The Company generally places loans on nonaccrual status when the full and timely collection of interest or principal becomes uncertain, when part of the principal balance has been charged off and no restructuring has occurred, or the loans reach a certain number of days past due. Generally, loans 90 days or more past due are placed on nonaccrual status, except for consumer loans, which are placed in nonaccrual status at 150 days past due. When a loan is placed on nonaccrual, the accrued unpaid interest receivable is reversed against interest income and all future payments received are applied as a reduction to the loan principal. Generally, the loan is returned to accrual status when (a) all delinquent interest and principal becomes current under the terms of the loan agreement or (b) the loan is both well-secured and in the process of collection and collectability is no longer in doubt. Impaired Loans Management considers loans to be impaired when, based on current information and events, it is determined that the Company will not be able to collect all amounts due according to the loan contract, including scheduled interest payments. Determination of impairment is treated the same across all loan categories. When management identifies a loan as impaired, the impairment is measured based on the present value of expected future cash flows, discounted at the loan’s effective interest rate, except when the sole source for repayment of the loan is the operation or liquidation of collateral. When the loan is collateral dependent, the appraised value less estimated cost to sell is utilized. If management determines the value of the impaired loan is less than the recorded investment in the loan, impairment is recognized through an allowance estimate or a charge-off to the allowance. Troubled debt restructured loans on accrual status are also considered to be impaired loans. When the ultimate collectability of the total principal of an impaired loan is in doubt and the loan is on nonaccrual status, all payments are applied to principal under the cost recovery method. When the ultimate collectability of the total principal of an impaired loan is not in doubt and the loan is on nonaccrual status, contractual interest is credited to interest income when received under the cash basis method. Significant nonaccrual loans as of June 30, 2016 , include the following: • $11.4 million relationship of commercial industrial loans to a steel and aluminum servicing company. These loans were originated in 2011 and were placed in nonaccrual status during the first quarter of 2016. A valuation of the collateral was completed during the second quarter of 2016. • $10.5 million relationship of commercial industrial loans to a manufacturer of mine safety products. These loans were originated from 2014 to 2015 and were placed in nonaccrual status during the second quarter of 2016. All collateral valuations were completed in June 2016. • $4.4 million relationship of commercial industrial loans to an oil and gas well services company. These loans were originated in 2014 and were placed in nonaccrual status during the fourth quarter of 2015. During the six months ended June 30, 2016 , charge-offs of $2.0 million related to this relationship were recorded. All collateral valuations were completed in June 2016. • $3.7 million relationship of commercial industrial loans to a local energy company involved in the drilling and production of natural gas wells. These loans were originated from 2008 to 2011 and were placed in nonaccrual status during the third quarter of 2013. Two of these loans were modified resulting in TDR classification: one loan totaling $1.3 million was modified in 2012, and the other loan totaling $2.4 million was modified in 2014. During the six months ended June 30, 2016 , charge-offs of $1.1 million related to this relationship were recorded. A valuation of the collateral was updated during the first quarter of 2016. • $3.5 million relationship of commercial industrial loans to a gear manufacturer. These loans were originated in 2013 and were placed in nonaccrual status during the third quarter of 2015. During the six months ended June 30, 2016 , charge-offs of $0.2 million related to this relationship were recorded. A valuation of the collateral was completed during the second quarter of 2016. The following tables include the recorded investment and unpaid principal balance for impaired loans with the associated allowance amount, if applicable, as of June 30, 2016 and December 31, 2015 . Also presented are the average recorded investment in impaired loans and the related amount of interest recognized while the loan was considered impaired. Average balances are calculated using month-end balances of the loans for the period reported and are included in the table below based on their period-end allowance position. June 30, 2016 December 31, 2015 Recorded Unpaid Related Recorded Unpaid Related (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 16,078 $ 23,373 $ 11,344 $ 15,673 Real estate construction — — 28 117 Residential real estate 11,580 13,674 9,952 11,819 Commercial real estate 6,390 8,043 7,562 9,449 Loans to individuals 376 450 421 507 Subtotal 34,424 45,540 29,307 37,565 With an allowance recorded: Commercial, financial, agricultural and other 28,522 30,849 15,018 20,132 22,590 6,952 Real estate construction — — — — — — Residential real estate 551 680 48 461 672 51 Commercial real estate 911 939 464 944 1,008 42 Loans to individuals — — — — — — Subtotal 29,984 32,468 15,530 21,537 24,270 7,045 Total $ 64,408 $ 78,008 $ 15,530 $ 50,844 $ 61,835 $ 7,045 For the Six Months Ended June 30, 2016 2015 Average Interest Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 20,116 $ 249 $ 21,691 $ 120 Real estate construction 9 44 137 — Residential real estate 11,232 137 11,025 86 Commercial real estate 7,136 67 8,760 43 Loans to individuals 442 3 312 2 Subtotal 38,935 500 41,925 251 With an allowance recorded: Commercial, financial, agricultural and other 17,939 91 5,337 72 Real estate construction — — — — Residential real estate 347 — 319 — Commercial real estate 861 11 194 3 Loans to individuals — — — — Subtotal 19,147 102 5,850 75 Total $ 58,082 $ 602 $ 47,775 $ 326 For the Three Months Ended June 30, 2016 2015 Average Interest Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 18,995 $ 95 $ 18,526 $ 65 Real estate construction — — 36 — Residential real estate 11,462 90 11,302 45 Commercial real estate 6,887 29 8,682 24 Loans to individuals 405 2 316 1 Subtotal 37,749 216 38,862 135 With an allowance recorded: Commercial, financial, agricultural and other 22,788 65 5,237 42 Real estate construction — — — — Residential real estate 476 — 329 — Commercial real estate 921 6 193 1 Loans to individuals — — — — Subtotal 24,185 71 5,759 43 Total $ 61,934 $ 287 $ 44,621 $ 178 Unfunded commitments related to nonperforming loans were $2.2 million at June 30, 2016 and $0.1 million at December 31, 2015 . After consideration of the requirements to draw and available collateral related to these commitments, a reserve of $24 thousand and $13 thousand was established for these off balance sheet exposures at June 30, 2016 and December 31, 2015 , respectively. Troubled debt restructured loans are those loans whose terms have been renegotiated to provide a reduction or deferral of principal or interest as a result of the financial difficulties experienced by the borrower, who could not obtain comparable terms from alternate financing sources. The following table provides detail as to the total troubled debt restructured loans and total commitments outstanding on troubled debt restructured loans: June 30, 2016 December 31, 2015 (dollars in thousands) Troubled debt restructured loans Accrual status $ 16,332 $ 14,139 Nonaccrual status 9,672 12,360 Total $ 26,004 $ 26,499 Commitments Unused lines of credit $ 577 $ 3,252 The following tables provide detail, including specific reserves and reasons for modification, related to loans identified as troubled debt restructurings: For the Six Months Ended June 30, 2016 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 5 $ 92 $ 4,009 $ — $ 4,101 $ 3,708 $ 40 Residential real estate 26 — 114 2,416 2,530 2,440 — Commercial real estate 6 1,264 — 25 1,289 1,227 74 Loans to individuals 5 — 29 11 40 30 — Total 42 $ 1,356 $ 4,152 $ 2,452 $ 7,960 $ 7,405 $ 114 For the Six Months Ended June 30, 2015 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 3 $ 1,751 $ — $ 109 $ 1,860 $ 1,812 $ 53 Residential real estate 16 — 296 503 799 723 7 Commercial real estate 1 — — 463 463 428 — Loans to individuals 6 — 61 18 79 66 — Total 26 $ 1,751 $ 357 $ 1,093 $ 3,201 $ 3,029 $ 60 The troubled debt restructurings included in the above tables are also included in the impaired loan tables provided earlier in this note. Loans defined as modified due to a change in rate may include loans that were modified for a change in rate as well as a reamortization of the principal and an extension of the maturity. For the six months ended June 30, 2016 and 2015 , $4.2 million and $0.4 million , respectively, of total rate modifications represent loans with modifications to the rate as well as payment as a result of reamortization. For both 2016 and 2015 the changes in loan balances between the pre-modification balance and the post-modification balance are due to customer payments. The following tables provide detail, including specific reserves and reasons for modification, related to loans identified as troubled debt restructurings: For the Three Months Ended June 30, 2016 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 4 $ 92 $ 240 $ — $ 332 $ 217 $ 40 Residential real estate 17 — — 1,435 1,435 1,428 — Commercial real estate 4 1,198 — — 1,198 1,173 74 Loans to individuals 2 — 11 6 17 15 — Total 27 $ 1,290 $ 251 $ 1,441 $ 2,982 $ 2,833 $ 114 For the Three Months Ended, June 30, 2015 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 2 $ 252 $ — $ 109 $ 361 $ 317 $ 53 Residential real estate 11 — 45 485 530 525 7 Loans to individuals 5 — 61 — 61 56 — Total 18 $ 252 $ 106 $ 594 $ 952 $ 898 $ 60 The troubled debt restructurings included in the above tables are also included in the impaired loan tables provided earlier in this note. Loans defined as modified due to a change in rate may include loans that were modified for a change in rate as well as a reamortization of the principal and an extension of the maturity. For the three months ended June 30, 2016 and 2015 , $0.3 million and $0.1 million , respectively, of total rate modifications represent loans with modifications to the rate as well as payment as a result of reamortization. For both 2016 and 2015 the changes in loan balances between the pre-modification balance and the post-modification balance are due to customer payments. A troubled debt restructuring is considered to be in default when a restructured loan is 90 days or more past due. The following table provides information related to restructured loans that were considered to be in default during the six months ended June 30 : 2016 2015 Number of Recorded Number of Recorded (dollars in thousands) Residential real estate — $ — 2 $ 56 Total — $ — 2 $ 56 The following table provides information related to restructured loans that were considered to be in default during the three months ended June 30 : 2016 2015 Number of Recorded Number of Recorded (dollars in thousands) Residential real estate — $ — 2 $ 56 Total — $ — 2 $ 56 The following tables provide detail related to the allowance for credit losses: For the Six Months Ended June 30, 2016 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 31,035 $ 887 $ 2,606 $ 11,924 $ 4,360 $ 50,812 Charge-offs (6,145 ) — (602 ) (408 ) (2,491 ) (9,646 ) Recoveries 198 227 260 783 289 1,757 Provision (credit) 21,269 (634 ) 341 (6,437 ) 2,359 16,898 Ending Balance $ 46,357 $ 480 $ 2,605 $ 5,862 $ 4,517 $ 59,821 Ending balance: individually evaluated for impairment $ 15,018 $ — $ 48 $ 464 $ — $ 15,530 Ending balance: collectively evaluated for impairment 31,339 480 2,557 5,398 4,517 44,291 Loans: Ending balance 1,185,062 242,132 1,199,005 1,648,222 569,355 4,843,776 Ending balance: individually evaluated for impairment 43,817 — 5,966 6,017 — 55,800 Ending balance: collectively evaluated for impairment 1,141,245 242,132 1,193,039 1,642,205 569,355 4,787,976 For the Six Months Ended June 30, 2015 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 29,627 $ 2,063 $ 3,664 $ 11,881 $ 4,816 $ 52,051 Charge-offs (7,940 ) — (1,050 ) (688 ) (2,383 ) (12,061 ) Recoveries 358 84 239 153 323 1,157 Provision (credit) 1,710 (629 ) 70 881 2,165 4,197 Ending Balance $ 23,755 $ 1,518 $ 2,923 $ 12,227 $ 4,921 $ 45,344 Ending balance: individually evaluated for impairment $ 1,596 $ — $ 35 $ 44 $ — $ 1,675 Ending balance: collectively evaluated for impairment 22,159 1,518 2,888 12,183 4,921 43,669 Loans: Ending balance 1,098,019 125,010 1,204,499 1,416,841 646,485 4,490,854 Ending balance: individually evaluated for impairment 21,419 — 7,700 7,625 — 36,744 Ending balance: collectively evaluated for impairment 1,076,600 125,010 1,196,799 1,409,216 646,485 4,454,110 For the Three Months Ended June 30, 2016 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 41,721 $ 901 $ 2,628 $ 5,483 $ 4,489 $ 55,222 Charge-offs (4,753 ) — (220 ) (143 ) (1,022 ) (6,138 ) Recoveries 64 4 142 27 128 365 Provision (credit) 9,325 (425 ) 55 495 922 10,372 Ending Balance $ 46,357 $ 480 $ 2,605 $ 5,862 $ 4,517 $ 59,821 For the Three Months Ended, June 30, 2015 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 24,406 $ 1,528 $ 3,387 $ 12,487 $ 4,889 $ 46,697 Charge-offs (2,860 ) — (484 ) (486 ) (1,122 ) (4,952 ) Recoveries 158 84 143 15 161 561 Provision (credit) 2,051 (94 ) (123 ) 211 993 3,038 Ending Balance $ 23,755 $ 1,518 $ 2,923 $ 12,227 $ 4,921 $ 45,344

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes At June 30, 2016 and December 31, 2015 , First Commonwealth had no material unrecognized tax benefits or accrued interest and penalties. If applicable, First Commonwealth will record interest and penalties as a component of noninterest expense. Federal and state tax years 2012 through 2014 are open for examination as of June 30, 2016 .

Fair Values of Assets and Liabi

Fair Values of Assets and Liabilities	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Values of Assets and Liabilities	Fair Values of Assets and Liabilities FASB ASC Topic 820, “Fair Value Measurements and Disclosures,” requires disclosures for non-financial assets and non-financial liabilities, except for items that are recognized or disclosed at fair value in the financial statements on a recurring basis (at least annually). All non-financial assets are included either as a separate line item on the Condensed Consolidated Statements of Financial Condition or in the “Other assets” category of the Condensed Consolidated Statements of Financial Condition. Currently, First Commonwealth does not have any non-financial liabilities to disclose. FASB ASC Topic 825, “Financial Instruments”, permits entities to irrevocably elect to measure select financial instruments and certain other items at fair value. The unrealized gains and losses are required to be included in earnings each reporting period for the items that fair value measurement is elected. First Commonwealth has elected not to measure any existing financial instruments at fair value under FASB ASC Topic 825; however, in the future we may elect to adopt this guidance for select financial instruments. In accordance with FASB ASC Topic 820, First Commonwealth groups financial assets and financial liabilities measured at fair value in three levels based on the principal markets in which the assets and liabilities are transacted and the observability of the data points used to determine fair value. These levels are: • Level 1 – Valuations for assets and liabilities traded in active exchange markets, such as the New York Stock Exchange (“NYSE”). Valuations are obtained from readily available pricing sources for market transactions involving identical assets or liabilities. Level 1 securities include equity holdings comprised of publicly traded bank stocks which were priced using quoted market prices. • Level 2 – Valuations for assets and liabilities traded in less active dealer or broker markets. Valuations are obtained for identical or comparable assets or liabilities from alternative pricing sources with reasonable levels of price transparency. Level 2 includes Obligations of U.S. Government securities issued by Agencies and Sponsored Enterprises, Obligations of States and Political Subdivisions, corporate securities, FHLB stock, loans held for sale, interest rate derivatives (including interest rate caps, interest rate swaps and risk participation agreements), certain other real estate owned and certain impaired loans. Level 2 investment securities are valued by a recognized third party pricing service using observable inputs. The model used by the pricing service varies by asset class and incorporates available market, trade and bid information as well as cash flow information when applicable. Because many fixed-income investment securities do not trade on a daily basis, the model uses available information such as benchmark yield curves, benchmarking of like investment securities, sector groupings and matrix pricing. The model will also use processes such as an option adjusted spread to assess the impact of interest rates and to develop prepayment estimates. Market inputs normally used in the pricing model include benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers and reference data including market research publications. Management validates the market values provided by the third party service by having another recognized pricing service price 100% of the securities on an annual basis and a random sample of securities each quarter, monthly monitoring of variances from prior period pricing and, on a monthly basis, evaluating pricing changes compared to expectations based on changes in the financial markets. Other investments recorded in the Condensed Consolidated Statements of Financial Condition are comprised of FHLB stock whose estimated fair value is based on its par value. Additional information on FHLB stock is provided in Note 7, “Impairment of Investment Securities.” Loans held for sale include a commercial loan and residential mortgage loans originated for sale in the secondary mortgage market. The estimated fair value for these loans was determined on the basis of rates obtained in the respective secondary market. Interest rate derivatives are reported at an estimated fair value utilizing Level 2 inputs and are included in other assets and other liabilities, and consist of interest rate swaps where there is no significant deterioration in the counterparties' (loan customers') credit risk since origination of the interest rate swap as well as interest rate caps and risk participation agreements. First Commonwealth values its interest rate swap and cap positions using a yield curve by taking market prices/rates for an appropriate set of instruments. The set of instruments currently used to determine the U.S. Dollar yield curve includes cash LIBOR rates from overnight to three months, Eurodollar futures contracts and swap rates from three years to thirty years. These yield curves determine the valuations of interest rate swaps. Interest rate derivatives are further described in Note 11, “Derivatives.” For purposes of potential valuation adjustments to our derivative positions, First Commonwealth evaluates the credit risk of its counterparties as well as our own credit risk. Accordingly, we have considered factors such as the likelihood of default, expected loss given default, net exposures and remaining contractual life, among other things, in determining if any fair value adjustments related to credit risk are required. We review our counterparty exposure quarterly, and when necessary, appropriate adjustments are made to reflect the exposure. We also utilize this approach to estimate our own credit risk on derivative liability positions. In 2016 , we have not realized any losses due to a counterparty's inability to pay any uncollateralized positions. The estimated fair value for other real estate owned included in Level 2 is determined by either an independent market-based appraisal less estimated costs to sell or an executed sales agreement. • Level 3 – Valuations for assets and liabilities that are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. If the inputs used to provide the valuation are unobservable and/or there is very little, if any, market activity for the security or similar securities, the securities would be considered Level 3 securities. Level 3 valuations incorporate certain assumptions and projections in determining the fair value assigned to such assets or liabilities. The assets included in Level 3 are pooled trust preferred collateralized debt obligations, non-marketable equity investments, certain interest rate derivatives, certain other real estate owned and certain impaired loans. Our pooled trust preferred collateralized debt obligations are collateralized by the trust preferred securities of individual banks, thrifts and bank holding companies in the United States. There has been little or no active trading in these securities since 2009; therefore, it is more appropriate to determine estimated fair value using a discounted cash flow analysis. Detail on our process for determining the appropriate cash flows for this analysis is provided in Note 7, “Impairment of Investment Securities.” The discount rate applied to the cash flows is determined by evaluating the current market yields for comparable corporate and structured credit products along with an evaluation of the risks associated with the cash flows of the comparable security. Due to the fact that there is no active market for the pooled trust preferred collateralized debt obligations, one key reference point is the market yield for the single issue trust preferred securities issued by banks and thrifts for which there is more activity than for the pooled securities. Adjustments are then made to reflect the credit and structural differences between these two security types. Management validates the fair value of the pooled trust preferred collateralized debt obligations by monitoring the performance of the underlying collateral, discussing the discount rate, cash flow assumptions and general market trends with a specialized third party and confirming changes in the underlying collateral to the trustee reports. Management’s monitoring of the underlying collateral includes deferrals of interest payments, payment defaults, cures of previously deferred interest payments, any regulatory filings or actions and general news related to the underlying collateral. Management also evaluates fair value changes compared to expectations based on changes in the interest rates used in determining the discount rate and general financial markets. The estimated fair value of the non-marketable equity investments included in Level 3 is based on par value. The estimated fair value of limited partnership investments included in Level 3 is based on par value. For interest rate derivatives included in Level 3, the fair value incorporates credit risk by considering such factors as likelihood of default and expected loss given default based on the credit quality of the underlying counterparties (loan customers). In accordance with ASU 2011 -4 , the following table provides information related to quantitative inputs and assumptions used in Level 3 fair value measurements. Fair Value (dollars Valuation Unobservable Inputs Range / Pooled Trust Preferred Securities $ 33,723 Discounted Cash Flow Probability of default 0% - 100% (11.47%) Prepayment rates 0% - 73.03% (5.14%) Discount rates 5.50% - 12.50% (a) Equities 1,670 Par Value N/A N/A Impaired Loans 2,414 (b) Reserve study Discount rate 10.00% Gas per MCF $1.63 - $3.38 (c) Oil per BBL/d $40.97 - $56.16 (c) 6,815 (b) Discounted Cash Flow Discount Rate 1.90% - 4.68% Limited Partnership Investments 704 Par Value N/A N/A (a) Incorporates spread over risk free rate related primarily to credit quality and illiquidity of securities. (b) The remainder of impaired loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation. (c) Unobservable inputs are defined as follows: MCF - million cubic feet; BBL/d - barrels per day. The significant unobservable inputs used in the fair value measurement of pooled trust preferred securities are the probability of default, discount rates and prepayment rates. Significant increases in the probability of default or discount rate used would result in a decrease in the estimated fair value of these securities, while decreases in these variables would result in higher fair value measurements. In general, a change in the assumption of probability of default is accompanied by a directionally similar change in the discount rate. In most cases, increases in the prepayment rate assumptions would result in a higher estimated fair value for these securities while decreases would provide for a lower value. The direction of this change is somewhat dependent on the structure of the investment and the amount of the investment tranches senior to our position. The discount rate is the significant unobservable input used in the fair value measurement of impaired loans. Significant increases in this rate would result in a decrease in the estimated fair value of the loans, while a decrease in this rate would result in a higher fair value measurement. Other unobservable inputs in the fair value measurement of impaired loans relate to gas, oil and natural gas prices. Increases in these prices would result in an increase in the estimated fair value of the loans, while a decrease in these prices would result in a lower fair value measurement. The tables below present the balances of assets and liabilities measured at fair value on a recurring basis: June 30, 2016 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities - Residential $ — $ 18,762 $ — $ 18,762 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities - Residential — 747,396 — 747,396 Mortgage-Backed Securities - Commercial — 2 — 2 Other Government-Sponsored Enterprises — 19,322 — 19,322 Obligations of States and Political Subdivisions — 28,036 — 28,036 Corporate Securities — 6,422 — 6,422 Pooled Trust Preferred Collateralized Debt Obligations — — 33,723 33,723 Total Debt Securities — 819,940 33,723 853,663 Equities — — 1,670 1,670 Total Securities Available for Sale — 819,940 35,393 855,333 Other Investments — 58,087 — 58,087 Loans held for sale — 11,613 — 11,613 Other Assets(a) — 22,382 704 23,086 Total Assets $ — $ 912,022 $ 36,097 $ 948,119 Other Liabilities(a) $ — $ 21,405 $ — $ 21,405 Total Liabilities $ — $ 21,405 $ — $ 21,405 (a) Hedging and non-hedging interest rate derivatives December 31, 2015 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities - Residential $ — $ 22,092 $ — $ 22,092 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities - Residential — 777,577 — 777,577 Mortgage-Backed Securities - Commercial — 28 — 28 Other Government-Sponsored Enterprises — 19,118 — 19,118 Obligations of States and Political Subdivisions — 27,598 — 27,598 Corporate Securities — 2,319 — 2,319 Pooled Trust Preferred Collateralized Debt Obligations — — 35,658 35,658 Total Debt Securities — 848,732 35,658 884,390 Equities — — 2,170 2,170 Total Securities Available for Sale — 848,732 37,828 886,560 Other Investments — 62,952 — 62,952 Loans held for sale — 5,763 — 5,763 Other Assets(a) — 11,273 — 11,273 Total Assets $ — $ 928,720 $ 37,828 $ 966,548 Other Liabilities(a) $ — $ 10,829 $ — $ 10,829 Total Liabilities $ — $ 10,829 $ — $ 10,829 (a) Hedging and non-hedging interest rate derivatives For the six months ended June 30 , changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows: 2016 Pooled Trust Preferred Collateralized Debt Obligations Equities Other Total (dollars in thousands) Balance, beginning of period $ 35,658 $ 2,170 $ — $ 37,828 Total gains or losses Included in earnings — — — — Included in other comprehensive income (1,905 ) — — (1,905 ) Purchases, issuances, sales and settlements Purchases — 36 168 204 Issuances — — — — Sales — — — — Settlements (30 ) — — (30 ) Transfers from Level 3 — (536 ) — (536 ) Transfers into Level 3 — — 536 536 Balance, end of period $ 33,723 $ 1,670 $ 704 $ 36,097 2015 Pooled Trust Preferred Collateralized Debt Obligations Equities Total (dollars in thousands) Balance, beginning of period $ 28,999 $ 1,420 $ 30,419 Total gains or losses Included in earnings 105 — 105 Included in other comprehensive income 7,471 — 7,471 Purchases, issuances, sales and settlements Purchases — 500 500 Issuances — — — Sales — — — Settlements (1,054 ) — (1,054 ) Transfers into Level 3 — — — Balance, end of period $ 35,521 $ 1,920 $ 37,441 During the six months ended June 30, 2016 , $0.5 million in investments in limited partnerships were moved from other equity securities to other assets constituting the transfers into and out of Level 3. During the six months ended June 30, 2015 , there were no transfers between fair value Levels 1 , 2 or 3. There were no gains or losses included in earnings for the periods presented that are attributable to the change in realized gains (losses) relating to assets held at June 30, 2016 and 2015 . For the three months ended June 30 , changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows: 2016 Pooled Trust Preferred Collateralized Debt Obligations Equities Other Total (dollars in thousands) Balance, beginning of period $ 33,273 $ 2,206 $ — $ 35,479 Total gains or losses Included in earnings — — — — Included in other comprehensive income 480 — — 480 Purchases, issuances, sales and settlements Purchases — — 168 168 Issuances — — — — Sales — — — — Settlements (30 ) — — (30 ) Transfers from Level 3 — (536 ) — (536 ) Transfers into Level 3 — — 536 536 Balance, end of period $ 33,723 $ 1,670 $ 704 $ 36,097 2015 Pooled Trust Preferred Collateralized Debt Obligations Equities Total (dollars in thousands) Balance, beginning of period $ 31,134 $ 1,920 33,054 Total gains or losses Included in earnings — — — Included in other comprehensive income 4,851 — 4,851 Purchases, issuances, sales and settlements Purchases — — — Issuances — — — Sales — — — Settlements (464 ) — (464 ) Transfers into Level 3 — — — Balance, end of period $ 35,521 $ 1,920 $ 37,441 During the three months ended June 30, 2016 , $0.5 million in investments in limited partnerships were moved from other equity securities to other assets constituting the transfers into and out of Level 3. During the three months ended June 30, 2015 , there were no transfers between fair value Levels 1 , 2 or 3. There were no gains or losses included in earnings for the periods presented that are attributable to the change in realized gains (losses) relating to assets held at June 30, 2016 and 2015 . The tables below present the balances of assets measured at fair value on a nonrecurring basis at: June 30, 2016 Level 1 Level 2 Level 3 Total (dollars in thousands) Impaired loans $ — $ 30,774 $ 18,104 $ 48,878 Other real estate owned — 10,036 — 10,036 Total Assets $ — $ 40,810 $ 18,104 $ 58,914 December 31, 2015 Level 1 Level 2 Level 3 Total (dollars in thousands) Impaired loans $ — $ 30,979 $ 12,820 $ 43,799 Other real estate owned — 10,039 8 10,047 Total Assets $ — $ 41,018 $ 12,828 $ 53,846 The following losses were realized on the assets measured on a nonrecurring basis: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 (dollars in thousands) Impaired loans $ (6,991 ) $ (382 ) $ (14,576 ) $ (843 ) Other real estate owned (245 ) (1,126 ) (258 ) (1,154 ) Total losses $ (7,236 ) $ (1,508 ) $ (14,834 ) $ (1,997 ) Impaired loans over $100 thousand are individually reviewed to determine the amount of each loan considered to be at risk of non-collection. The fair value for impaired loans that are collateral based is determined by reviewing real property appraisals, equipment valuations, accounts receivable listings and other financial information. A discounted cash flow analysis is performed to determine fair value for impaired loans when an observable market price or a current appraisal is not available. For real estate secured loans, First Commonwealth’s loan policy requires updated appraisals be obtained at least every twelve months on all impaired loans with balances of $250 thousand and over. For real estate secured loans with balances under $250 thousand , we rely on broker price opinions. For non-real estate secured assets, the Company normally relies on third party valuations specific to the collateral type. The fair value for other real estate owned, determined by either an independent market-based appraisal less estimated costs to sell or an executed sales agreement, is classified as Level 2. The fair value for other real estate owned determined using an internal valuation is classified as Level 3. Other real estate owned has a current carrying value of $8.6 million as of June 30, 2016 and consists primarily of commercial real estate properties in Pennsylvania. We review whether events and circumstances subsequent to a transfer to other real estate owned have occurred that indicate the balance of those assets may not be recoverable. If events and circumstances indicate further impairment we will record a charge to the extent that the carrying value of the assets exceed their fair values, less estimated cost to sell, as determined by valuation techniques appropriate in the circumstances. Certain other assets and liabilities, including goodwill and core deposit intangibles, are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. Additional information related to goodwill is provided in Note 12, “Goodwill.” There were no other assets or liabilities measured at fair value on a nonrecurring basis during the six months ended June 30, 2016 . FASB ASC 825-10, “Transition Related to FSP FAS 107 -1 ” and APB 28 -1 , “Interim Disclosures about Fair Value of Financial Instruments,” requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or nonrecurring basis. The methodologies for estimating the fair value of financial assets and financial liabilities that are measured at fair value on a recurring or nonrecurring basis are as discussed above. The methodologies for other financial assets and financial liabilities are discussed below. Cash and due from banks and interest-bearing bank deposits : The carrying amounts for cash and due from banks and interest-bearing bank deposits approximate the estimated fair values of such assets. Securities : Fair values for securities available for sale and held to maturity are based on quoted market prices, if available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments. Pooled trust preferred collateralized debt obligations values are derived from other valuation methodologies, including option pricing models, discounted cash flow models and similar techniques, and not based on market exchange, dealer or broker traded transactions. These valuations incorporate certain assumptions and projections in determining the fair value assigned to each instrument. The carrying value of other investments, which includes FHLB stock, is considered a reasonable estimate of fair value. Loans : The fair values of all loans are estimated by discounting the estimated future cash flows using interest rates currently offered for loans with similar terms to borrowers of similar credit quality adjusted for past due and nonperforming loans, which is not an exit price under FASB ASC Topic 820, “Fair Value Measurements and Disclosures.” Loans Held for Sale : The estimated fair value of loans held for sale is based on market bids obtained from potential buyers. Off-balance sheet instruments : Many of First Commonwealth’s off-balance sheet instruments, primarily loan commitments and standby letters of credit, are expected to expire without being drawn upon; therefore, the commitment amounts do not necessarily represent future cash requirements. FASB ASC Topic 460, “Guarantees” clarified that a guarantor is required to recognize, at the inception of a guarantee, a liability for the fair value of the obligation undertaken in issuing the guarantee. The carrying amount and fair value for standby letters of credit was $0.2 million and $0.2 million at June 30, 2016 and December 31, 2015 , respectively. See Note 5, “Commitments and Contingent Liabilities,” for additional information. Deposit liabilities : The estimated fair value of demand deposits, savings accounts and money market deposits is the amount payable on demand at the reporting date because of the customers’ ability to withdraw funds immediately. The carrying value of variable rate time deposit accounts and certificates of deposit approximate their fair values at the report date. Also, fair values of fixed rate time deposits for both periods are estimated by discounting the future cash flows using interest rates currently being offered and a schedule of aggregated expected maturities. Short-term borrowings : The fair values of borrowings from the FHLB were estimated based on the estimated incremental borrowing rate for similar types of borrowings. The carrying amounts of other short-term borrowings such as federal funds purchased and securities sold under agreement to repurchase were used to approximate fair value due to the short-term nature of the borrowings. Long-term debt and subordinated debt : The fair value of long-term debt and subordinated debt is estimated by discounting the future cash flows using First Commonwealth’s estimate of the current market rate for similar types of borrowing arrangements or an announced redemption price. The following table presents carrying amounts and fair values of First Commonwealth’s financial instruments: June 30, 2016 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 68,163 $ 68,163 $ 68,163 $ — $ — Interest-bearing deposits 30,457 30,457 30,457 — — Securities available for sale 855,333 855,333 — 819,940 35,393 Securities held to maturity 405,976 414,770 — 414,770 — Other investments 58,087 58,087 — 58,087 — Loans held for sale 11,613 11,613 — 11,613 — Loans 4,843,776 4,857,127 — 30,774 4,826,353 Financial liabilities Deposits 4,394,520 4,395,297 — 4,395,297 — Short-term borrowings 1,464,687 1,464,408 — 1,464,408 — Subordinated debt 72,167 61,427 — — 61,427 Long-term debt 9,034 10,077 — 10,077 — December 31, 2015 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 66,644 $ 66,644 $ 66,644 $ — $ — Interest-bearing deposits 2,808 2,808 2,808 — — Securities available for sale 886,560 886,560 — 848,732 37,828 Other investments 62,952 62,952 — 62,952 — Loans held for sale 5,763 5,763 — 5,763 — Loans 4,683,750 4,690,852 — 30,979 4,659,873 Financial liabilities Deposits 4,195,894 4,198,817 — 4,198,817 — Short-term borrowings 1,510,825 1,510,718 — 1,510,718 — Subordinated debt 72,167 62,794 — — 62,794 Long-term debt 9,314 9,834 — 9,834 —

Derivatives

Derivatives	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives Derivatives Not Designated as Hedging Instruments First Commonwealth is a party to interest rate derivatives that are not designated as hedging instruments. These derivatives relate to interest rate swaps that First Commonwealth enters into with customers to allow customers to convert variable rate loans to a fixed rate. First Commonwealth pays interest to the customer at a floating rate on the notional amount and receives interest from the customer at a fixed rate for the same notional amount. At the same time the interest rate swap is entered into with the customer, an offsetting interest rate swap is entered into with another financial institution. First Commonwealth pays the other financial institution interest at the same fixed rate on the same notional amount as the swap entered into with the customer, and receives interest from the financial institution for the same floating rate on the same notional amount. The changes in the fair value of the swaps offset each other, except for the credit risk of the counterparties, which is determined by taking into consideration the risk rating, probability of default and loss given default for all counterparties. We have 22 risk participation agreements with financial institution counterparties for interest rate swaps related to loans in which we are a participant. The risk participation agreements provide credit protection to the financial institution should the borrower fail to perform on its interest rate derivative contract with the financial institution. We have seven risk participation agreements with financial institution counterparties for interest rate swaps related to loans in which we are the lead bank. The risk participation agreement provides credit protection to us should the borrower fail to perform on its interest rate derivative contract with us. First Commonwealth is also party to interest rate caps that are not designated as hedging instruments. These derivatives relate to contracts that First Commonwealth enters into with loan customers that provide a maximum interest rate on their variable rate loan. At the same time the interest rate cap is entered into with the customer, First Commonwealth enters into an offsetting interest rate cap with another financial institution. The notional amount and maximum interest rate on both interest cap contracts are identical. The fee received, less the estimate of the loss for the credit exposure, was recognized in earnings at the time of the transaction. Derivatives Designated as Hedging Instruments The Company has entered into four interest rate swap contracts that were designated as cash flow hedges. The interest rate swaps have a total notional amount of $200.0 million , $85.0 million with an original maturity of three years and $115.0 million with and original maturity of four years. The Company's risk management objective for these hedges is to reduce its exposure to variability in expected future cash flows related to interest payments on commercial loans benchmarked to the 1-month LIBOR rate. Therefore, the interest rate swaps convert the interest payments on the first $200.0 million of 1-month LIBOR based commercial loans into fixed rate payments. The periodic net settlement of interest rate swaps is recorded as an adjustment to "Interest and fees on loans" in the Condensed Consolidated Statements of Income. For the three and six months ended June 30, 2016 , there was a $0.9 million impact on interest income as a result of these interest rate swaps. Changes in the fair value of the effective portion of cash flow hedges are reported in OCI. When the cash flows associated with the hedged item are realized, the gain or loss included in OCI is recognized in "Interest and fees on loans," the same line item in the Condensed Consolidated Statements of Income as the income on the hedged items. The cash flow hedges were highly effective at June 30, 2016 , and December 31, 2015 , and changes in the fair value attributed to hedge ineffectiveness were not material. The following table depicts the credit value adjustment recorded related to the notional amount of derivatives outstanding as well as the notional amount of risk participation agreements participated to other banks: June 30, 2016 December 31, 2015 (dollars in thousands) Derivatives not Designated as Hedging Instruments Credit value adjustment $ (2,075 ) $ (542 ) Notional Amount: Interest rate derivatives 324,630 276,860 Interest rate caps 21,168 22,793 Risk participation agreements 164,850 126,612 Sold credit protection on risk participation agreements (35,786 ) (20,383 ) Derivatives Designated as Hedging Instruments Fair value adjustment (3,015 ) 922 Notional Amount - Interest rate derivatives 200,000 200,000 The table below presents the amount representing the change in the fair value of derivative assets and derivative liabilities attributable to credit risk included in "Other income" on the Condensed Consolidated Statements of Income: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 (dollars in thousands) Non-hedging interest rate derivatives (Decrease) increase in other income $ (531 ) $ 593 $ (1,545 ) $ 363 Hedging interest rate derivatives Increase in interest and fees on loans 424 557 854 938 Increase in other expense 26 12 41 21 The fair value of our derivatives is included in a table in Note 18, “Fair Values of Assets and Liabilities,” in the line items “Other assets” and “Other liabilities.”

Goodwill

Goodwill	6 Months Ended
	Jun. 30, 2016
Goodwill Disclosure [Abstract]
Goodwill	Goodwill FASB ASC Topic 350-20, “Intangibles – Goodwill and Other” requires an annual valuation of the fair value of a reporting unit that has goodwill and a comparison of the fair value to the book value of equity to determine whether the goodwill has been impaired. Goodwill is also required to be tested on an interim basis if an event or circumstance indicates that it is more likely than not that an impairment loss has been incurred. When triggering events or circumstances indicate that goodwill testing is required, an assessment of qualitative factors can be completed before performing the two step goodwill impairment test. ASU 2011-8 provides that if an assessment of qualitative factors determines it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, then the two step goodwill impairment test is not required. We consider First Commonwealth to be one reporting unit. The carrying amount of goodwill as of June 30, 2016 and December 31, 2015 was $164.5 million . No impairment charges on goodwill or other intangible assets were incurred in 2016 or 2015 . We test goodwill for impairment as of November 30th each year and again at any quarter-end if any material events occur during a quarter that may affect goodwill. As of June 30, 2016 , goodwill was not considered impaired; however, changing economic conditions that may adversely affect our performance, the fair value of our assets and liabilities, or our stock price could result in impairment, which could adversely affect earnings in future periods. Management will continue to monitor events that could impact this conclusion in the future.

New Accounting Pronouncements (

New Accounting Pronouncements (Notes)	6 Months Ended
	Jun. 30, 2016
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements In August 2015, the FASB issued ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606). ” In May 2014, the FASB issued ASU No. 2014-09, "Revenue from Contracts with Customers (Topic 606)," with an original effective date for annual reporting periods beginning after December 15, 2016. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2015-14 deferred the effective date of ASU 2014-09 to annual periods and interim periods within those annual periods beginning after December 15, 2017. We are currently evaluating the potential impact of ASU 2015-14 on our financial statements. In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments - Overall (Subtopic 825-10)," which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This ASU addresses: 1. requiring equity investments to be measured at fair value, recognizing the changes in fair value through net income; 2. simplifying the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; 3. eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for entities that are not public entities; 4. eliminating the requirement for public entities to disclose the methods and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost; 5. requiring public entities to use the exit price notion when measuring the fair value of financial instruments; 6. requiring and entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; 7. requiring separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or in the accompanying notes to the financial statements; and 8. clarifying that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity's other deferred tax assets. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017 for public entities and for fiscal years beginning after December 15, 2018 for entities that are not public entities. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)," in order to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases, and operating leases. Leveraged leases have been eliminated, although lessors can continue to account for existing leveraged leases using the current accounting guidance. Other limited changes were made to align lessor accounting with the lessee accounting model and the new revenue recognition standard. All entities will classify leases to determine how to recognize lease-related revenue and expense. Quantitative and qualitative disclosures will be required by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The intention is to require enough information to supplement the amounts recorded in the financial statements so that users can understand more about the nature of an entity’s leasing activities. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. All entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. Entities have the option to use certain relief; full retrospective application is prohibited. Management has not yet evaluated the impact of the ASU on First Commonwealth's financial condition or results of operations and will be monitoring developments and additional guidance closely to determine the potential impact of the new standard. In March 2016, FASB issued ASU No. 2016-05, "Derivatives and Hedging (Topic 815)," which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. This ASU is effective for public entities beginning after December 15, 2016, and interim periods within those fiscal years. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In March 2016, FASB issued ASU No. 2016-09, “Compensation - Stock Compensation (Topic 718) - Improvements to Employee Share-Based Payment Accounting.” This update requires all income tax effects of awards to be recognized in the income statement when the awards vest or are settled. It also allows an employer to repurchase more of an employee’s shares than it can today for tax withholding purposes without triggering liability accounting and to make a policy election for forfeitures as they occur. The guidance is effective for public business entities for fiscal years beginning after December 15, 2016, and interim periods within those years. Early adoption is permitted. The adoption of this ASU is not expected to have a material impact on First Commonwealth’s financial condition or results of operations. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments – Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments,” which amends the guidance for recognizing credit losses from an “incurred loss” methodology that delays recognition of credit losses until it is probable a loss has been incurred to an expected credit loss methodology. The guidance requires the use of the modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. The standard is effective for the Company as of January 1, 2020. Management is currently evaluating the impact of the amended guidance on First Commonwealth’s financial condition or results of operations.

Subsequent Event (Notes)

Subsequent Event (Notes)	6 Months Ended
	Jun. 30, 2016
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Event On July 27, 2016, the Company announced that it had reached an agreement with FirstMerit Bank, NA to acquire 13 retail branches in Canton and Ashtabula, Ohio with approximately $735 million of deposits and $115 million of performing retail and business loans. This transaction is subject to regulatory approval and is expected to close in the fourth quarter of 2016.

Supplemental Comprehensive In23

Supplemental Comprehensive Income Disclosures (Tables)	6 Months Ended
	Jun. 30, 2016
Supplemental Comprehensive Income Disclosures [Abstract]
Supplemental Comprehensive Income Disclosures	The following table identifies the related tax effects allocated to each component of other comprehensive income (“OCI”) in the Condensed Consolidated Statements of Comprehensive Income. Reclassification adjustments related to securities available for sale are included in the "Net securities gains" line and reclassification adjustments related to losses on derivatives are included in the "Other operating expenses" line in the Condensed Consolidated Statements of Income. For the Six Months Ended June 30, 2016 2015 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains on securities: Unrealized holding gains on securities arising during the period $ 13,872 $ (4,855 ) $ 9,017 $ 6,166 $ (2,156 ) $ 4,010 Reclassification adjustment for gains on securities included in net income (28 ) 10 (18 ) (125 ) 44 (81 ) Total unrealized gains on securities 13,844 (4,845 ) 8,999 6,041 (2,112 ) 3,929 Unrealized gains on derivatives: Unrealized holding gains on derivatives arising during the period 2,094 (733 ) 1,361 668 (234 ) 434 Reclassification adjustment for gains on derivatives included in net income (41 ) 14 (27 ) (6 ) 2 (4 ) Total unrealized gains on derivatives 2,053 (719 ) 1,334 662 (232 ) 430 Total other comprehensive income $ 15,897 $ (5,564 ) $ 10,333 $ 6,703 $ (2,344 ) $ 4,359 For the Three Months Ended June 30, 2016 2015 Pretax Amount Tax (Expense) Benefit Net of Tax Amount Pretax Amount Tax (Expense) Benefit Net of Tax Amount (dollars in thousands) Unrealized gains (losses) on securities: Unrealized holding gains (losses) on securities arising during the period $ 3,802 $ (1,331 ) $ 2,471 $ (3,814 ) $ 1,335 $ (2,479 ) Reclassification adjustment for gains on securities included in net income (28 ) 10 (18 ) (20 ) 7 (13 ) Total unrealized gains (losses) on securities 3,774 (1,321 ) 2,453 (3,834 ) 1,342 (2,492 ) Unrealized gains (losses) on derivatives: Unrealized holding gains (losses) on derivatives arising during the period 359 (126 ) 233 (527 ) 184 (343 ) Reclassification adjustment for gains on derivatives included in net income (26 ) 9 (17 ) (11 ) 4 (7 ) Total unrealized gains (losses) on derivatives 333 (117 ) 216 (538 ) 188 (350 ) Total other comprehensive income (loss) $ 4,107 $ (1,438 ) $ 2,669 $ (4,372 ) $ 1,530 $ (2,842 )
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table details the change in components of OCI for the six months ended June 30 : 2016 2015 Securities Available for Sale Post-Retirement Obligation Derivatives Accumulated Other Comprehensive Income Securities Available for Sale Post-Retirement Obligation Derivatives Accumulated Other Comprehensive Income (dollars in thousands) Balance at December 31 $ (2,956 ) $ 10 $ 560 $ (2,386 ) $ (4,875 ) $ 76 $ 300 $ (4,499 ) Other comprehensive income before reclassification adjustment 9,017 — 1,361 10,378 4,010 — 434 4,444 Amounts reclassified from accumulated other comprehensive (loss) income (18 ) — (27 ) (45 ) (81 ) — (4 ) (85 ) Net other comprehensive income during the period 8,999 — 1,334 10,333 3,929 — 430 4,359 Balance at June 30 $ 6,043 $ 10 $ 1,894 $ 7,947 $ (946 ) $ 76 $ 730 $ (140 )

Supplemental Cash Flow Disclo24

Supplemental Cash Flow Disclosures (Tables)	6 Months Ended
	Jun. 30, 2016
Supplemental Cash Flow Information [Abstract]
Schedule of Supplemental Cash Flow Disclosures	The following table presents information related to cash paid during the period for interest, as well as detail on non-cash investing and financing activities for the six months ended June 30 : 2016 2015 (dollars in thousands) Cash paid during the period for: Interest $ 9,583 $ 7,893 Income taxes 10,500 4,000 Non-cash investing and financing activities: Loans transferred to other real estate owned and repossessed assets 2,632 2,315 Loans transferred from held to maturity to held for sale 3,573 3,071 Gross increase in market value adjustment to securities available for sale 13,845 6,036 Gross increase in market value adjustment to derivatives 2,053 662 Investments committed to purchase, not settled 1,946 1,817 Proceeds from death benefit on bank-owned life insurance not received 523 —

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Composition of Weighted-Average Common Shares (Denominator) Used in Basic and Diluted Earnings Per Share	The following table summarizes the composition of the weighted-average common shares (denominator) used in the basic and diluted earnings per share computations: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 Weighted average common shares issued 105,563,455 105,563,455 105,563,455 105,563,455 Average treasury stock shares (16,620,341 ) (16,445,760 ) (16,621,717 ) (15,480,232 ) Average unearned nonvested shares (111,356 ) (195,303 ) (105,815 ) (189,561 ) Weighted average common shares and common stock equivalents used to calculate basic earnings per share 88,831,758 88,922,392 88,835,923 89,893,662 Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share 6,856 16,611 4,760 9,888 Weighted average common shares and common stock equivalents used to calculate diluted earnings per share 88,838,614 88,939,003 88,840,683 89,903,550
Common Stock Equivalents Not Included in Computation of Diluted Earnings Per Share	The following table shows the number of shares and the price per share related to common stock equivalents that were not included in the computation of diluted earnings per share for the six months ended June 30 because to do so would have been antidilutive. 2016 2015 Price Range Price Range Shares From To Shares From To Restricted Stock 81,887 7.57 9.84 146,933 5.26 9.26

Commitments and Contingent Li26

Commitments and Contingent Liabilities (Tables)	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Notional Amount of Outstanding Commitments	The following table identifies the notional amount of those instruments at: June 30, 2016 December 31, 2015 (dollars in thousands) Financial instruments whose contract amounts represent credit risk: Commitments to extend credit $ 1,616,286 $ 1,643,187 Financial standby letters of credit 19,256 17,843 Performance standby letters of credit 28,067 26,497 Commercial letters of credit 1,615 1,672

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2016
Schedule of Held-to-maturity Securities [Line Items]
Analysis of Amortized Cost and Estimated Fair Value of Securities Available for Sale	Below is an analysis of the amortized cost and estimated fair values of securities available for sale at: June 30, 2016 December 31, 2015 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 16,730 $ 2,032 $ — $ 18,762 $ 20,034 $ 2,071 $ (13 ) $ 22,092 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 732,618 15,012 (234 ) 747,396 778,476 7,983 (8,882 ) 777,577 Mortgage-Backed Securities – Commercial 2 — — 2 28 — — 28 Other Government-Sponsored Enterprises 19,300 22 — 19,322 19,201 2 (85 ) 19,118 Obligations of States and Political Subdivisions 27,071 965 — 28,036 27,066 532 — 27,598 Corporate Securities 5,898 524 — 6,422 1,897 422 — 2,319 Pooled Trust Preferred Collateralized Debt Obligations 42,750 500 (9,527 ) 33,723 42,239 916 (7,497 ) 35,658 Total Debt Securities 844,369 19,055 (9,761 ) 853,663 888,941 11,926 (16,477 ) 884,390 Equities 1,670 — — 1,670 2,170 — — 2,170 Total Securities Available for Sale $ 846,039 $ 19,055 $ (9,761 ) $ 855,333 $ 891,111 $ 11,926 $ (16,477 ) $ 886,560
Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale	The amortized cost and estimated fair value of debt securities available for sale at June 30, 2016 , by contractual maturity, are shown below. Amortized Estimated (dollars in thousands) Due within 1 year $ 2,601 $ 2,602 Due after 1 but within 5 years 20,696 20,780 Due after 5 but within 10 years 27,070 28,036 Due after 10 years 44,652 36,085 95,019 87,503 Mortgage-Backed Securities (a) 749,350 766,160 Total Debt Securities $ 844,369 $ 853,663 (a) Mortgage Backed Securities include an amortized cost of $16.7 million and a fair value of $18.8 million for Obligations of U.S.
Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale	Proceeds from sales, gross gains (losses) realized on sales, maturities and other-than-temporary impairment charges related to securities available for sale were as follows for the six months ended June 30 : 2016 2015 (dollars in thousands) Proceeds from sales $ 55,744 $ — Gross gains (losses) realized: Sales Transactions: Gross gains $ 304 $ — Gross losses (276 ) — 28 — Maturities and impairment Gross gains — 105 Gross losses — — Other-than-temporary impairment — — — 105 Net gains and impairment $ 28 $ 105

Investment Securities Maturity

Investment Securities Maturity of Held-to-Maturity Securities (Tables)	6 Months Ended
	Jun. 30, 2016
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities [Table Text Block]	Below is an analysis of the amortized cost and fair values of debt securities held to maturity at: June 30, 2016 December 31, 2015 Amortized Gross Gross Estimated Amortized Gross Gross Estimated (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 4,712 $ 146 $ — $ 4,858 $ 4,775 $ — $ (7 ) $ 4,768 Mortgage-Backed Securities- Commercial 36,529 403 — 36,932 16,843 — (247 ) 16,596 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 313,987 6,746 — 320,733 315,609 30 (1,824 ) 313,815 Mortgage-Backed Securities – Commercial 14,940 460 — 15,400 15,187 — (178 ) 15,009 Obligations of States and Political Subdivisions 35,808 1,039 — 36,847 31,910 301 (58 ) 32,153 Total Securities Held to Maturity $ 405,976 $ 8,794 $ — $ 414,770 $ 384,324 $ 331 $ (2,314 ) $ 382,341
Schedule of Held-to-Maturity Securities by Maturity [Table Text Block]	The amortized cost and estimated fair value of debt securities held to maturity at June 30, 2016 , by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Amortized Estimated (dollars in thousands) Due within 1 year $ — $ — Due after 1 but within 5 years 1,231 1,265 Due after 5 but within 10 years 28,052 28,940 Due after 10 years 6,525 6,642 35,808 36,847 Mortgage-Backed Securities (a) 370,168 377,923 Total Debt Securities $ 405,976 $ 414,770 (a) Mortgage Backed Securities include an amortized cost of $41.2 million and a fair value of $41.8 million for Obligations of U.S. Government agencies issued by Ginnie Mae and an amortized cost of $328.9 million and a fair value of $336.1 million for Obligations of U.S. Government-sponsored enterprises issued by Fannie Mae and Freddie Mac.

Impairment of Investment Secu29

Impairment of Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2016
Impairment of Investment Securities Disclosure [Abstract]
Schedule of Unrealized Losses and Estimated Fair Values	The following table presents the gross unrealized losses and estimated fair values at December 31, 2015 by investment category and time frame for which securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities – Residential $ 6,798 $ (20 ) $ — $ — $ 6,798 $ (20 ) Mortgage-Backed Securities - Commercial 16,596 (247 ) — — 16,596 (247 ) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential 436,011 (3,293 ) 263,119 (7,413 ) 699,130 (10,706 ) Mortgage-Backed Securities – Commercial 15,009 (178 ) — — 15,009 (178 ) Other Government-Sponsored Enterprises 12,316 (85 ) — — 12,316 (85 ) Obligation of States and Political Subdivisions 7,208 (58 ) — — 7,208 (58 ) Pooled Trust Preferred Collateralized Debt Obligations — — 29,957 (7,497 ) 29,957 (7,497 ) Total Securities $ 493,938 $ (3,881 ) $ 293,076 $ (14,910 ) $ 787,014 $ (18,791 ) The following table presents the gross unrealized losses and estimated fair values at June 30, 2016 for both available for sale and held to maturity securities by investment category and time frame for which securities have been in a continuous unrealized loss position: Less Than 12 Months 12 Months or More Total Estimated Gross Estimated Gross Estimated Gross (dollars in thousands) Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities – Residential $ 15,227 $ (13 ) $ 64,716 $ (221 ) $ 79,943 $ (234 ) Pooled Trust Preferred Collateralized Debt Obligations — — 28,276 (9,527 ) 28,276 (9,527 ) Total Securities $ 15,227 $ (13 ) $ 92,992 $ (9,748 ) $ 108,219 $ (9,761 )
Pooled Trust Preferred Collateralized Debt Obligations	The following table provides information related to our pooled trust preferred collateralized debt obligations as of June 30, 2016 : Deal Class Book Estimated Fair Unrealized Moody’s/ Number Deferrals Excess (dollars in thousands) Pre TSL IV Mezzanine $ 1,830 $ 1,301 $ (529 ) B1/BB 6 18.05 % 58.51 % Pre TSL VII Mezzanine 3,061 3,324 263 Ca/- 14 49.68 — Pre TSL VIII Mezzanine 2,042 1,691 (351 ) C/C 28 53.00 — Pre TSL IX Mezzanine 2,394 1,797 (597 ) B1/C 38 29.80 9.73 Pre TSL X Mezzanine 1,675 1,817 142 Caa1/C 43 32.22 2.20 Pre TSL XII Mezzanine 5,786 4,442 (1,344 ) B3/C 66 22.03 — Pre TSL XIII Mezzanine 12,828 9,971 (2,857 ) Ba3/C 56 11.34 47.86 Pre TSL XIV Mezzanine 12,924 9,075 (3,849 ) B1/CC 56 15.21 38.08 MMCap I Mezzanine 210 305 95 Ca/C 8 58.11 81.96 Total $ 42,750 $ 33,723 $ (9,027 )
Cumulative Roll Forward of Credit Losses Recognized in Earnings for Debt Securities held and not Intended to be Sold	The following table provides a cumulative roll forward of credit losses recognized in earnings for debt securities held and not intended to be sold: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 (dollars in thousands) Balance, beginning (a) $ 24,590 $ 25,707 $ 24,851 $ 26,246 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — — — Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — — — Increases in cash flows expected to be collected, recognized over the remaining life of the security (b) (280 ) (341 ) (541 ) (662 ) Reduction for debt securities called during the period — — — (218 ) Balance, ending $ 24,310 $ 25,366 $ 24,310 $ 25,366 (a) The beginning balance represents credit related losses included in other-than-temporary impairment charges recognized on debt securities in prior periods. (b) Represents the increase in cash flows recognized in interest income during the period.

Loans and Allowance for Credi30

Loans and Allowance for Credit Losses (Tables)	6 Months Ended
	Jun. 30, 2016
Loans and Leases Receivable Disclosure [Abstract]
Outstanding Balances of Loan	The following table provides outstanding balances related to each of our loan types: June 30, 2016 December 31, 2015 (dollars in thousands) Commercial, financial, agricultural and other $ 1,185,062 $ 1,150,906 Real estate construction 242,132 220,736 Residential real estate 1,199,005 1,224,465 Commercial real estate 1,648,222 1,479,000 Loans to individuals 569,355 608,643 Total loans $ 4,843,776 $ 4,683,750
Credit Risk Profile by Creditworthiness	The following tables represent our credit risk profile by creditworthiness: June 30, 2016 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 1,095,516 $ 241,840 $ 1,183,847 $ 1,625,206 $ 569,087 $ 4,715,496 Non-Pass OAEM 11,923 292 6,846 7,221 — 26,282 Substandard 77,623 — 8,312 15,795 268 101,998 Doubtful — — — — — — Total Non-Pass 89,546 292 15,158 23,016 268 128,280 Total $ 1,185,062 $ 242,132 $ 1,199,005 $ 1,648,222 $ 569,355 $ 4,843,776 December 31, 2015 Commercial, financial, agricultural and other Real estate construction Residential real estate Commercial real estate Loans to individuals Total (dollars in thousands) Pass $ 1,074,858 $ 220,267 $ 1,209,606 $ 1,436,714 $ 608,342 $ 4,549,787 Non-Pass OAEM 11,825 442 5,244 30,012 — 47,523 Substandard 64,223 27 9,615 12,274 301 86,440 Doubtful — — — — — — Total Non-Pass 76,048 469 14,859 42,286 301 133,963 Total $ 1,150,906 $ 220,736 $ 1,224,465 $ 1,479,000 $ 608,643 $ 4,683,750
Age Analysis of Past Due Loans by Segment	The following tables delineate the aging analysis of the recorded investments in past due loans as of June 30, 2016 and December 31, 2015 . Also included in these tables are loans that are 90 days or more past due and still accruing because they are well-secured and in the process of collection. June 30, 2016 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 2,344 $ 714 $ 283 $ 37,429 $ 40,770 $ 1,144,292 $ 1,185,062 Real estate construction — — — — — 242,132 242,132 Residential real estate 4,544 1,542 243 6,448 12,777 1,186,228 1,199,005 Commercial real estate 1,166 — 1 3,931 5,098 1,643,124 1,648,222 Loans to individuals 2,072 700 857 268 3,897 565,458 569,355 Total $ 10,126 $ 2,956 $ 1,384 $ 48,076 $ 62,542 $ 4,781,234 $ 4,843,776 December 31, 2015 30 - 59 60 - 89 90 days Nonaccrual Total past Current Total (dollars in thousands) Commercial, financial, agricultural and other $ 364 $ 49 $ 129 $ 23,653 $ 24,195 $ 1,126,711 $ 1,150,906 Real estate construction 280 — — 28 308 220,428 220,736 Residential real estate 4,175 1,055 1,315 6,500 13,045 1,211,420 1,224,465 Commercial real estate 781 — 65 6,223 7,069 1,471,931 1,479,000 Loans to individuals 2,998 774 946 301 5,019 603,624 608,643 Total $ 8,598 $ 1,878 $ 2,455 $ 36,705 $ 49,636 $ 4,634,114 $ 4,683,750
Recorded Investment and Unpaid Principal Balance for Impaired Loans with Associated Allowance	The following tables include the recorded investment and unpaid principal balance for impaired loans with the associated allowance amount, if applicable, as of June 30, 2016 and December 31, 2015 . Also presented are the average recorded investment in impaired loans and the related amount of interest recognized while the loan was considered impaired. Average balances are calculated using month-end balances of the loans for the period reported and are included in the table below based on their period-end allowance position. June 30, 2016 December 31, 2015 Recorded Unpaid Related Recorded Unpaid Related (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 16,078 $ 23,373 $ 11,344 $ 15,673 Real estate construction — — 28 117 Residential real estate 11,580 13,674 9,952 11,819 Commercial real estate 6,390 8,043 7,562 9,449 Loans to individuals 376 450 421 507 Subtotal 34,424 45,540 29,307 37,565 With an allowance recorded: Commercial, financial, agricultural and other 28,522 30,849 15,018 20,132 22,590 6,952 Real estate construction — — — — — — Residential real estate 551 680 48 461 672 51 Commercial real estate 911 939 464 944 1,008 42 Loans to individuals — — — — — — Subtotal 29,984 32,468 15,530 21,537 24,270 7,045 Total $ 64,408 $ 78,008 $ 15,530 $ 50,844 $ 61,835 $ 7,045 For the Six Months Ended June 30, 2016 2015 Average Interest Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 20,116 $ 249 $ 21,691 $ 120 Real estate construction 9 44 137 — Residential real estate 11,232 137 11,025 86 Commercial real estate 7,136 67 8,760 43 Loans to individuals 442 3 312 2 Subtotal 38,935 500 41,925 251 With an allowance recorded: Commercial, financial, agricultural and other 17,939 91 5,337 72 Real estate construction — — — — Residential real estate 347 — 319 — Commercial real estate 861 11 194 3 Loans to individuals — — — — Subtotal 19,147 102 5,850 75 Total $ 58,082 $ 602 $ 47,775 $ 326 For the Three Months Ended June 30, 2016 2015 Average Interest Average Interest (dollars in thousands) With no related allowance recorded: Commercial, financial, agricultural and other $ 18,995 $ 95 $ 18,526 $ 65 Real estate construction — — 36 — Residential real estate 11,462 90 11,302 45 Commercial real estate 6,887 29 8,682 24 Loans to individuals 405 2 316 1 Subtotal 37,749 216 38,862 135 With an allowance recorded: Commercial, financial, agricultural and other 22,788 65 5,237 42 Real estate construction — — — — Residential real estate 476 — 329 — Commercial real estate 921 6 193 1 Loans to individuals — — — — Subtotal 24,185 71 5,759 43 Total $ 61,934 $ 287 $ 44,621 $ 178
Troubled Debt Restructured Loans and Commitments	The following tables provide detail, including specific reserves and reasons for modification, related to loans identified as troubled debt restructurings: For the Three Months Ended June 30, 2016 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 4 $ 92 $ 240 $ — $ 332 $ 217 $ 40 Residential real estate 17 — — 1,435 1,435 1,428 — Commercial real estate 4 1,198 — — 1,198 1,173 74 Loans to individuals 2 — 11 6 17 15 — Total 27 $ 1,290 $ 251 $ 1,441 $ 2,982 $ 2,833 $ 114 For the Three Months Ended, June 30, 2015 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 2 $ 252 $ — $ 109 $ 361 $ 317 $ 53 Residential real estate 11 — 45 485 530 525 7 Loans to individuals 5 — 61 — 61 56 — Total 18 $ 252 $ 106 $ 594 $ 952 $ 898 $ 60 The following table provides detail as to the total troubled debt restructured loans and total commitments outstanding on troubled debt restructured loans: June 30, 2016 December 31, 2015 (dollars in thousands) Troubled debt restructured loans Accrual status $ 16,332 $ 14,139 Nonaccrual status 9,672 12,360 Total $ 26,004 $ 26,499 Commitments Unused lines of credit $ 577 $ 3,252 The following tables provide detail, including specific reserves and reasons for modification, related to loans identified as troubled debt restructurings: For the Six Months Ended June 30, 2016 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 5 $ 92 $ 4,009 $ — $ 4,101 $ 3,708 $ 40 Residential real estate 26 — 114 2,416 2,530 2,440 — Commercial real estate 6 1,264 — 25 1,289 1,227 74 Loans to individuals 5 — 29 11 40 30 — Total 42 $ 1,356 $ 4,152 $ 2,452 $ 7,960 $ 7,405 $ 114 For the Six Months Ended June 30, 2015 Type of Modification Number Extend Modify Modify Total Post- Specific (dollars in thousands) Commercial, financial, agricultural and other 3 $ 1,751 $ — $ 109 $ 1,860 $ 1,812 $ 53 Residential real estate 16 — 296 503 799 723 7 Commercial real estate 1 — — 463 463 428 — Loans to individuals 6 — 61 18 79 66 — Total 26 $ 1,751 $ 357 $ 1,093 $ 3,201 $ 3,029 $ 60
Troubled Debt Restructuring Subsequent Default [Table Text Block]	A troubled debt restructuring is considered to be in default when a restructured loan is 90 days or more past due. The following table provides information related to restructured loans that were considered to be in default during the six months ended June 30 : 2016 2015 Number of Recorded Number of Recorded (dollars in thousands) Residential real estate — $ — 2 $ 56 Total — $ — 2 $ 56 The following table provides information related to restructured loans that were considered to be in default during the three months ended June 30 : 2016 2015 Number of Recorded Number of Recorded (dollars in thousands) Residential real estate — $ — 2 $ 56 Total — $ — 2 $ 56
Allowance for Credit Losses	he following tables provide detail related to the allowance for credit losses: For the Six Months Ended June 30, 2016 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 31,035 $ 887 $ 2,606 $ 11,924 $ 4,360 $ 50,812 Charge-offs (6,145 ) — (602 ) (408 ) (2,491 ) (9,646 ) Recoveries 198 227 260 783 289 1,757 Provision (credit) 21,269 (634 ) 341 (6,437 ) 2,359 16,898 Ending Balance $ 46,357 $ 480 $ 2,605 $ 5,862 $ 4,517 $ 59,821 Ending balance: individually evaluated for impairment $ 15,018 $ — $ 48 $ 464 $ — $ 15,530 Ending balance: collectively evaluated for impairment 31,339 480 2,557 5,398 4,517 44,291 Loans: Ending balance 1,185,062 242,132 1,199,005 1,648,222 569,355 4,843,776 Ending balance: individually evaluated for impairment 43,817 — 5,966 6,017 — 55,800 Ending balance: collectively evaluated for impairment 1,141,245 242,132 1,193,039 1,642,205 569,355 4,787,976 For the Six Months Ended June 30, 2015 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 29,627 $ 2,063 $ 3,664 $ 11,881 $ 4,816 $ 52,051 Charge-offs (7,940 ) — (1,050 ) (688 ) (2,383 ) (12,061 ) Recoveries 358 84 239 153 323 1,157 Provision (credit) 1,710 (629 ) 70 881 2,165 4,197 Ending Balance $ 23,755 $ 1,518 $ 2,923 $ 12,227 $ 4,921 $ 45,344 Ending balance: individually evaluated for impairment $ 1,596 $ — $ 35 $ 44 $ — $ 1,675 Ending balance: collectively evaluated for impairment 22,159 1,518 2,888 12,183 4,921 43,669 Loans: Ending balance 1,098,019 125,010 1,204,499 1,416,841 646,485 4,490,854 Ending balance: individually evaluated for impairment 21,419 — 7,700 7,625 — 36,744 Ending balance: collectively evaluated for impairment 1,076,600 125,010 1,196,799 1,409,216 646,485 4,454,110 For the Three Months Ended June 30, 2016 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 41,721 $ 901 $ 2,628 $ 5,483 $ 4,489 $ 55,222 Charge-offs (4,753 ) — (220 ) (143 ) (1,022 ) (6,138 ) Recoveries 64 4 142 27 128 365 Provision (credit) 9,325 (425 ) 55 495 922 10,372 Ending Balance $ 46,357 $ 480 $ 2,605 $ 5,862 $ 4,517 $ 59,821 For the Three Months Ended, June 30, 2015 Commercial, Real estate Residential Commercial Loans to Total (dollars in thousands) Allowance for credit losses: Beginning Balance $ 24,406 $ 1,528 $ 3,387 $ 12,487 $ 4,889 $ 46,697 Charge-offs (2,860 ) — (484 ) (486 ) (1,122 ) (4,952 ) Recoveries 158 84 143 15 161 561 Provision (credit) 2,051 (94 ) (123 ) 211 993 3,038 Ending Balance $ 23,755 $ 1,518 $ 2,923 $ 12,227 $ 4,921 $ 45,344

Fair Values of Assets and Lia31

Fair Values of Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Inputs, Assets, Quantitative Information	In accordance with ASU 2011 -4 , the following table provides information related to quantitative inputs and assumptions used in Level 3 fair value measurements. Fair Value (dollars Valuation Unobservable Inputs Range / Pooled Trust Preferred Securities $ 33,723 Discounted Cash Flow Probability of default 0% - 100% (11.47%) Prepayment rates 0% - 73.03% (5.14%) Discount rates 5.50% - 12.50% (a) Equities 1,670 Par Value N/A N/A Impaired Loans 2,414 (b) Reserve study Discount rate 10.00% Gas per MCF $1.63 - $3.38 (c) Oil per BBL/d $40.97 - $56.16 (c) 6,815 (b) Discounted Cash Flow Discount Rate 1.90% - 4.68% Limited Partnership Investments 704 Par Value N/A N/A (a) Incorporates spread over risk free rate related primarily to credit quality and illiquidity of securities. (b) The remainder of impaired loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation. (c) Unobservable inputs are defined as follows: MCF - million cubic feet; BBL/d - barrels per day.
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The tables below present the balances of assets and liabilities measured at fair value on a recurring basis: June 30, 2016 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities - Residential $ — $ 18,762 $ — $ 18,762 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities - Residential — 747,396 — 747,396 Mortgage-Backed Securities - Commercial — 2 — 2 Other Government-Sponsored Enterprises — 19,322 — 19,322 Obligations of States and Political Subdivisions — 28,036 — 28,036 Corporate Securities — 6,422 — 6,422 Pooled Trust Preferred Collateralized Debt Obligations — — 33,723 33,723 Total Debt Securities — 819,940 33,723 853,663 Equities — — 1,670 1,670 Total Securities Available for Sale — 819,940 35,393 855,333 Other Investments — 58,087 — 58,087 Loans held for sale — 11,613 — 11,613 Other Assets(a) — 22,382 704 23,086 Total Assets $ — $ 912,022 $ 36,097 $ 948,119 Other Liabilities(a) $ — $ 21,405 $ — $ 21,405 Total Liabilities $ — $ 21,405 $ — $ 21,405 (a) Hedging and non-hedging interest rate derivatives December 31, 2015 Level 1 Level 2 Level 3 Total (dollars in thousands) Obligations of U.S. Government Agencies: Mortgage-Backed Securities - Residential $ — $ 22,092 $ — $ 22,092 Obligations of U.S. Government-Sponsored Enterprises: Mortgage-Backed Securities - Residential — 777,577 — 777,577 Mortgage-Backed Securities - Commercial — 28 — 28 Other Government-Sponsored Enterprises — 19,118 — 19,118 Obligations of States and Political Subdivisions — 27,598 — 27,598 Corporate Securities — 2,319 — 2,319 Pooled Trust Preferred Collateralized Debt Obligations — — 35,658 35,658 Total Debt Securities — 848,732 35,658 884,390 Equities — — 2,170 2,170 Total Securities Available for Sale — 848,732 37,828 886,560 Other Investments — 62,952 — 62,952 Loans held for sale — 5,763 — 5,763 Other Assets(a) — 11,273 — 11,273 Total Assets $ — $ 928,720 $ 37,828 $ 966,548 Other Liabilities(a) $ — $ 10,829 $ — $ 10,829 Total Liabilities $ — $ 10,829 $ — $ 10,829 (a) Hedging and non-hedging interest rate derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	For the six months ended June 30 , changes in Level 3 assets and liabilities measured at fair value on a recurring basis are summarized as follows: 2016 Pooled Trust Preferred Collateralized Debt Obligations Equities Other Total (dollars in thousands) Balance, beginning of period $ 35,658 $ 2,170 $ — $ 37,828 Total gains or losses Included in earnings — — — — Included in other comprehensive income (1,905 ) — — (1,905 ) Purchases, issuances, sales and settlements Purchases — 36 168 204 Issuances — — — — Sales — — — — Settlements (30 ) — — (30 ) Transfers from Level 3 — (536 ) — (536 ) Transfers into Level 3 — — 536 536 Balance, end of period $ 33,723 $ 1,670 $ 704 $ 36,097 2015 Pooled Trust Preferred Collateralized Debt Obligations Equities Total (dollars in thousands) Balance, beginning of period $ 28,999 $ 1,420 $ 30,419 Total gains or losses Included in earnings 105 — 105 Included in other comprehensive income 7,471 — 7,471 Purchases, issuances, sales and settlements Purchases — 500 500 Issuances — — — Sales — — — Settlements (1,054 ) — (1,054 ) Transfers into Level 3 — — — Balance, end of period $ 35,521 $ 1,920 $ 37,441 2016 Pooled Trust Preferred Collateralized Debt Obligations Equities Other Total (dollars in thousands) Balance, beginning of period $ 33,273 $ 2,206 $ — $ 35,479 Total gains or losses Included in earnings — — — — Included in other comprehensive income 480 — — 480 Purchases, issuances, sales and settlements Purchases — — 168 168 Issuances — — — — Sales — — — — Settlements (30 ) — — (30 ) Transfers from Level 3 — (536 ) — (536 ) Transfers into Level 3 — — 536 536 Balance, end of period $ 33,723 $ 1,670 $ 704 $ 36,097 2015 Pooled Trust Preferred Collateralized Debt Obligations Equities Total (dollars in thousands) Balance, beginning of period $ 31,134 $ 1,920 33,054 Total gains or losses Included in earnings — — — Included in other comprehensive income 4,851 — 4,851 Purchases, issuances, sales and settlements Purchases — — — Issuances — — — Sales — — — Settlements (464 ) — (464 ) Transfers into Level 3 — — — Balance, end of period $ 35,521 $ 1,920 $ 37,441
Schedule of Assets Measured on Non-Recurring Basis	The tables below present the balances of assets measured at fair value on a nonrecurring basis at: June 30, 2016 Level 1 Level 2 Level 3 Total (dollars in thousands) Impaired loans $ — $ 30,774 $ 18,104 $ 48,878 Other real estate owned — 10,036 — 10,036 Total Assets $ — $ 40,810 $ 18,104 $ 58,914 December 31, 2015 Level 1 Level 2 Level 3 Total (dollars in thousands) Impaired loans $ — $ 30,979 $ 12,820 $ 43,799 Other real estate owned — 10,039 8 10,047 Total Assets $ — $ 41,018 $ 12,828 $ 53,846
Losses Realized on Assets Measured on Non-Recurring Basis	The following losses were realized on the assets measured on a nonrecurring basis: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 (dollars in thousands) Impaired loans $ (6,991 ) $ (382 ) $ (14,576 ) $ (843 ) Other real estate owned (245 ) (1,126 ) (258 ) (1,154 ) Total losses $ (7,236 ) $ (1,508 ) $ (14,834 ) $ (1,997 )
Carrying Amounts and Fair Values of Financial Instruments	The following table presents carrying amounts and fair values of First Commonwealth’s financial instruments: June 30, 2016 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 68,163 $ 68,163 $ 68,163 $ — $ — Interest-bearing deposits 30,457 30,457 30,457 — — Securities available for sale 855,333 855,333 — 819,940 35,393 Securities held to maturity 405,976 414,770 — 414,770 — Other investments 58,087 58,087 — 58,087 — Loans held for sale 11,613 11,613 — 11,613 — Loans 4,843,776 4,857,127 — 30,774 4,826,353 Financial liabilities Deposits 4,394,520 4,395,297 — 4,395,297 — Short-term borrowings 1,464,687 1,464,408 — 1,464,408 — Subordinated debt 72,167 61,427 — — 61,427 Long-term debt 9,034 10,077 — 10,077 — December 31, 2015 Fair Value Measurements Using: Carrying Total Level 1 Level 2 Level 3 (dollars in thousands) Financial assets Cash and due from banks $ 66,644 $ 66,644 $ 66,644 $ — $ — Interest-bearing deposits 2,808 2,808 2,808 — — Securities available for sale 886,560 886,560 — 848,732 37,828 Other investments 62,952 62,952 — 62,952 — Loans held for sale 5,763 5,763 — 5,763 — Loans 4,683,750 4,690,852 — 30,979 4,659,873 Financial liabilities Deposits 4,195,894 4,198,817 — 4,198,817 — Short-term borrowings 1,510,825 1,510,718 — 1,510,718 — Subordinated debt 72,167 62,794 — — 62,794 Long-term debt 9,314 9,834 — 9,834 —

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Credit Value Adjustment Recorded Related to Notional Amount Of Derivatives Outstanding	The following table depicts the credit value adjustment recorded related to the notional amount of derivatives outstanding as well as the notional amount of risk participation agreements participated to other banks: June 30, 2016 December 31, 2015 (dollars in thousands) Derivatives not Designated as Hedging Instruments Credit value adjustment $ (2,075 ) $ (542 ) Notional Amount: Interest rate derivatives 324,630 276,860 Interest rate caps 21,168 22,793 Risk participation agreements 164,850 126,612 Sold credit protection on risk participation agreements (35,786 ) (20,383 ) Derivatives Designated as Hedging Instruments Fair value adjustment (3,015 ) 922 Notional Amount - Interest rate derivatives 200,000 200,000
Schedule of Changes in Fair Value of Derivative Assets and Liabilities	The table below presents the amount representing the change in the fair value of derivative assets and derivative liabilities attributable to credit risk included in "Other income" on the Condensed Consolidated Statements of Income: For the Three Months Ended June 30, For the Six Months Ended June 30, 2016 2015 2016 2015 (dollars in thousands) Non-hedging interest rate derivatives (Decrease) increase in other income $ (531 ) $ 593 $ (1,545 ) $ 363 Hedging interest rate derivatives Increase in interest and fees on loans 424 557 854 938 Increase in other expense 26 12 41 21

Supplemental Comprehensive In33

Supplemental Comprehensive Income Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Supplemental Comprehensive Income Disclosures [Abstract]
Unrealized holding gains on securities arising during the period	$ 3,802	$ (3,814)	$ 13,872	$ 6,166
Reclassification adjustment for gains on securities included in net income	(28)	(20)	(28)	(125)
Total unrealized gains on securities	3,774	(3,834)	13,844	6,041
Unrealized holding gains (losses) on derivatives arising during the period	359	(527)	2,094	668
Unrealized holding gains on securities arising during the period	(1,331)	1,335	(4,855)	(2,156)
Reclassification adjustment for gains on derivatives included in net income, before Tax	(26)	(11)	(41)	(6)
Total unrealized gain on derivatives	333	(538)	2,053	662
Reclassification adjustment for gains on securities included in net income	10	7	10	44
Total other comprehensive (loss) income	4,107	(4,372)	15,897	6,703
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	(1,321)	1,342	(4,845)	(2,112)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(126)	184	(733)	(234)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	9	4	14	2
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Total	(117)	188	(719)	(232)
Other Comprehensive Income (Loss), Tax	(1,438)	1,530	(5,564)	(2,344)
Other comprehensive income (loss) before reclassification adjustment	2,471	(2,479)	9,017	4,010
Total unrealized (losses) gains on securities	2,453	(2,492)	8,999	3,929
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	233	(343)	1,361	434
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	17	7	27	4
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Total	216	(350)	1,334	430
Total other comprehensive (loss) income	2,669	(2,842)	10,333	4,359
Reclassification adjustment for gains on securities included in net income	$ 18	$ 13	$ 18	$ 81

Supplemental Comprehensive In34

Supplemental Comprehensive Income Disclosures (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			$ (2,386)	$ (4,499)
Other comprehensive income (loss) before reclassification adjustment	$ 2,471	$ (2,479)	9,017	4,010
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	233	(343)	1,361	434
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			10,378	4,444
Amounts reclassified from accumulated other comprehensive income (loss)			(45)	(85)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	17	7	27	4
Total other comprehensive (loss) income	2,669	(2,842)	10,333	4,359
Accumulated Other Comprehensive Income (Loss), Ending Balance	7,947	(140)	7,947	(140)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			(2,956)	(4,875)
Other comprehensive income (loss) before reclassification adjustment			9,017	4,010
Amounts reclassified from accumulated other comprehensive income (loss)			(18)	(81)
Total other comprehensive (loss) income			8,999	3,929
Accumulated Other Comprehensive Income (Loss), Ending Balance	6,043	(946)	6,043	(946)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			10	76
Other comprehensive income (loss) before reclassification adjustment			0	0
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Total other comprehensive (loss) income			0	0
Accumulated Other Comprehensive Income (Loss), Ending Balance	10	76	10	76
Derivative [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			560	300
Total other comprehensive (loss) income			1,334	430
Accumulated Other Comprehensive Income (Loss), Ending Balance	$ 1,894	$ 730	1,894	730
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive (loss) income			$ 10,333	$ 4,359

Supplemental Cash Flow Disclo35

Supplemental Cash Flow Disclosures - Non-cash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash paid during the period for:
Interest	$ 9,583	$ 7,893
Income Taxes Paid, Net	10,500	4,000
Non-cash investing and financing activities:
Loans Transferred to Other Real Estate Owned and Repossessions	2,632	2,315
Fair value of loans transferred from held to maturity to held for sale	3,573	3,071
Gross increase in market value adjustment to securities available for sale	13,845	6,036
Gross increase in market value adjustment to derivatives	2,053	662
Investments committed to purchase not settled	1,946	1,817
Unsettled Bank Owned Life Insurance Proceeds	$ 523	$ 0

Earnings per Share - Compositio

Earnings per Share - Composition of Weighted-Average Common Shares (Denominator) Used in Basic and Diluted Earnings Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Weighted Average Number of Shares Issued, Basic	105,563,455	105,563,455	105,563,455	105,563,455
Average treasury shares (in shares)	(16,620,341)	(16,445,760)	(16,621,717)	(15,480,232)
Average unearned nonvested shares	(111,356)	(195,303)	(105,815)	(189,561)
Weighted average common shares and common stock equivalents used to calculate basic earnings per share (in shares)	88,831,758	88,922,392	88,835,923	89,893,662
Additional common stock equivalents (nonvested stock) used to calculate diluted earnings per share	6,856	16,611	4,760	9,888
Weighted average common shares and common stock equivalents used to calculate diluted earnings per share (in shares)	88,838,614	88,939,003	88,840,683	89,903,550

Earnings per Share - Common Sto

Earnings per Share - Common Stock Equivalents Not Included in Computation of Diluted Earnings Per Share (Detail) - Restricted Stock [Member] - $ / shares	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	81,887	146,933
Minimum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount	$ 7.57	$ 5.26
Maximum [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Net Income, Per Outstanding Unit, Amount	$ 9.84	$ 9.26

Commitments and Contingent Li38

Commitments and Contingent Liabilities - Notional Amount of Outstanding Commitments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 1,616,286	$ 1,643,187
Financial standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	19,256	17,843
Performance standby letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	28,067	26,497
Commercial letters of credit [Member]
Loss Contingencies [Line Items]
Financial instrument of credit risk	$ 1,615	$ 1,672

Commitments and Contingent Li39

Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Notional Amount Of Performance Standby Letters Of Credit	$ 2,300,000
Notional Amount Of Commercial Letters Of Credit	201,000
Notional Amount Of Financial Standby Letters Of Credit	13,000
Financial instrument of credit risk	200,000	$ 200,000
Unfunded commitment liability	3,500,000	$ 4,400,000
Minimum [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	0
Maximum [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 7,000,000

Investment Securities - Analysi

Investment Securities - Analysis of Amortized Cost and Estimated Fair Values of Securities Available for Sale (Detail) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Investment Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis		$ 2,601
Amortized Cost		846,039	$ 891,111
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		19,055	11,926
Gross Unrealized Losses		(9,761)	(16,477)
Securities available for sale, at fair value		855,333	886,560
Due within one year, Estimated Fair Value		2,602
Due after one but within five years, Amortized Cost		20,696
Due after one but within five years, Estimated Fair Value		20,780
Due after five but within ten years, Amortized Cost		27,070
Due after five but within ten years, Estimated Fair Value		28,036
Due after ten years, Amortized Cost		44,652
Due after ten years, Estimated Fair Value		36,085
Due within one year, Amortized Cost		95,019
Available-for-sale Securities, Debt Maturities, Single Maturity Date		87,503
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[1]	749,350
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value	[1]	766,160
US Government Agencies Residential Mortgage-backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost		16,730
Securities available for sale, at fair value		18,762	22,092
Residential Mortgage Backed Securities [Member]
Investment Securities [Line Items]
Securities available for sale, at fair value		747,396	777,577
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Investment Securities [Line Items]
Securities available for sale, at fair value		2	28
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Securities available for sale, at fair value		19,322	19,118
Obligations of States and Political Subdivisions [Member]
Investment Securities [Line Items]
Securities available for sale, at fair value		28,036	27,598
Corporate Debt Securities [Member]
Investment Securities [Line Items]
Securities available for sale, at fair value		6,422	2,319
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Investment Securities [Line Items]
Securities available for sale, at fair value		33,723	35,658
Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost		844,369
Securities available for sale, at fair value		853,663
Equity Securities [Member]
Investment Securities [Line Items]
Amortized Cost		1,670	2,170
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		0	0
Gross Unrealized Losses		0	0
Securities available for sale, at fair value		1,670	2,170
Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost		844,369	888,941
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		19,055	11,926
Gross Unrealized Losses		(9,761)	(16,477)
Securities available for sale, at fair value		853,663	884,390
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Investment Securities [Line Items]
Amortized Cost		42,750	42,239
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		500	916
Gross Unrealized Losses		(9,527)	(7,497)
Securities available for sale, at fair value		33,723	35,658
Corporate Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost		5,898	1,897
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		524	422
Gross Unrealized Losses		0	0
Securities available for sale, at fair value		6,422	2,319
Obligations of States and Political Subdivisions [Member]
Investment Securities [Line Items]
Amortized Cost		27,071	27,066
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		965	532
Gross Unrealized Losses		0	0
Securities available for sale, at fair value		28,036	27,598
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost		19,300	19,201
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		22	2
Gross Unrealized Losses		0	(85)
Securities available for sale, at fair value		19,322	19,118
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Investment Securities [Line Items]
Amortized Cost		2	28
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		0	0
Gross Unrealized Losses		0	0
Securities available for sale, at fair value		2	28
Residential Mortgage Backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost		732,618	778,476
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		15,012	7,983
Gross Unrealized Losses		234	(8,882)
Securities available for sale, at fair value		747,396	777,577
US Government Agencies Residential Mortgage-backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost		16,730	20,034
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		2,032	2,071
Gross Unrealized Losses		0	(13)
Securities available for sale, at fair value		$ 18,762	$ 22,092
[1]	Mortgage Backed Securities include an amortized cost of $16.7 million and a fair value of $18.8 million for Obligations of U.S.

Investment Securities - Amortiz

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale (Detail) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Net Investment Income [Line Items]
Available-for-sale Securities, Debt Maturities, Single Maturity Date		$ 87,503
Due after five but within ten years, Amortized Cost		27,070
Due after one but within five years, Amortized Cost		20,696
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis	[1]	749,350
Due within one year, Amortized Cost		95,019
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis		2,601
Due after ten years, Amortized Cost		44,652
Corporate/Mortgage-Backed Securities, Amortized cost	[1]	766,160
Amortized Cost		846,039	$ 891,111
Due within one year, Estimated Fair Value		2,602
Due after one but within five years, Estimated Fair Value		20,780
Due after five but within ten years, Estimated Fair Value		28,036
Due after ten years, Estimated Fair Value		36,085
Total Debt Securities, Estimated Fair Value		855,333	886,560
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		19,055	11,926
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		9,761	16,477
US Government Agencies Debt Securities [Member]
Net Investment Income [Line Items]
Amortized Cost		16,730	20,034
Total Debt Securities, Estimated Fair Value		18,762	22,092
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		2,032	2,071
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		0	13
Debt Securities [Member]
Net Investment Income [Line Items]
Amortized Cost		844,369	888,941
Total Debt Securities, Estimated Fair Value		853,663	884,390
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		19,055	11,926
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		9,761	16,477
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Net Investment Income [Line Items]
Amortized Cost		732,600
Total Debt Securities, Estimated Fair Value		747,400
Debt Securities [Member]
Net Investment Income [Line Items]
Amortized Cost		844,369
Total Debt Securities, Estimated Fair Value		853,663
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Net Investment Income [Line Items]
Total Debt Securities, Estimated Fair Value		33,723	35,658
Corporate Debt Securities [Member]
Net Investment Income [Line Items]
Total Debt Securities, Estimated Fair Value		6,422	2,319
Obligations of States and Political Subdivisions [Member]
Net Investment Income [Line Items]
Total Debt Securities, Estimated Fair Value		28,036	27,598
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Net Investment Income [Line Items]
Total Debt Securities, Estimated Fair Value		19,322	19,118
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Net Investment Income [Line Items]
Total Debt Securities, Estimated Fair Value		2	28
Residential Mortgage Backed Securities [Member]
Net Investment Income [Line Items]
Total Debt Securities, Estimated Fair Value		747,396	777,577
US Government Agencies Debt Securities [Member]
Net Investment Income [Line Items]
Amortized Cost		16,730
Total Debt Securities, Estimated Fair Value		$ 18,762	$ 22,092
[1]	Mortgage Backed Securities include an amortized cost of $16.7 million and a fair value of $18.8 million for Obligations of U.S.

Investment Securities - Amort42

Investment Securities - Amortized Cost and Estimated Fair Value of Debt Securities Available for Sale (Detail) (1) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Investment Securities [Line Items]
Amortized Cost	$ 846,039	$ 891,111
Securities available for sale, at fair value	855,333	886,560
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	19,055	11,926
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	9,761	16,477
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	19,300	19,201
Securities available for sale, at fair value	19,322	19,118
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	22	2
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	85
US Government Agencies Residential Mortgage-backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost	16,730
Securities available for sale, at fair value	18,762	$ 22,092
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Investment Securities [Line Items]
Amortized Cost	732,600
Securities available for sale, at fair value	747,400
Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	844,369
Securities available for sale, at fair value	$ 853,663

Investment Securities - Proceed

Investment Securities - Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Investments, Debt and Equity Securities [Abstract]
Proceeds from Sale of Available-for-sale Securities	$ 55,744	$ 0
Sales Transactions:
Gross gains	304	0
Gross losses	(276)	0
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	28	0
Maturities and impairment
Gross Gains	0	105
Gross Losses	0	0
Other Than Temporary Impairment	0	0
Gain Losses Maturities And Impairment	0	105
Net gains and impairment	$ 28	$ 105

Investment Securities - Additio

Investment Securities - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Held-to-maturity Securities Pledged as Collateral	$ 291,500		$ 45,700
Proceeds from Sale of Available-for-sale Securities	55,744	$ 0
Available-for-sale securities pledged as collateral	$ 475,900		$ 416,100

Investment Securities Schedule

Investment Securities Schedule of Held-to-Maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Due within 1 year	$ 0
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	8,794	$ 331
Held-to-maturity Securities	405,976	384,324
Securities held to maturity, fair value	414,770	$ 382,341
Due after 1 but within 5 years	1,231
Due after 5 but within 10 years	28,052
Held-to-maturity Securities, Debt Maturities, Year Six Through Ten, Fair Value	28,940
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	1,265
Due after 10 years	6,525
Held-to-maturity Securities, Debt Maturities, after Ten Years, Fair Value	6,642
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis	35,808
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value	36,847
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Net Carrying Amount	370,168
Held-to-maturity Securities, Debt Maturities, without Single Maturity Date, Fair Value	377,923
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	41,241
Securities held to maturity, fair value	41,790
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	328,927
Securities held to maturity, fair value	$ 336,133

Investment Securities Held to M

Investment Securities Held to Maturity Securities by Type (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	$ 405,976	$ 384,324
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	8,794	331
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	(2,314)
Securities held to maturity, fair value	414,770	382,341
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	4,712	4,775
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	146	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	(7)
Securities held to maturity, fair value	4,858	4,768
US Government Agency Debt Securities Commercial [Domain]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	36,529	16,843
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	403	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	(247)
Securities held to maturity, fair value	36,932	16,596
Residential Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	313,987	315,609
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	6,746	30
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	(1,824)
Securities held to maturity, fair value	320,733	313,815
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	14,940	15,187
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	460	0
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	(178)
Securities held to maturity, fair value	15,400	15,009
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities	35,808	31,910
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	1,039	301
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	(58)
Securities held to maturity, fair value	$ 36,847	$ 32,153

Other Investments - Additional

Other Investments - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Other Investments Disclosure [Abstract]
Other investments	$ 58,087	$ 62,952

Impairment of Investment Secu48

Impairment of Investment Securities - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)SecurityBank	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)SecurityBank	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other than temporary impairment charges recognized			$ 0	$ 0
Amortized Cost	$ 846,039,000		846,039,000		$ 891,111,000
Securities available for sale, at fair value	$ 855,333,000		$ 855,333,000		886,560,000
Number of banks and other financial institutions comprising the security | Bank	274		274
Number Of Pooled Securities with No Senior Class | Security			3
Number of securities with no excess subordination | Security	3		3
Number of Securities with Excess Subordination | Security	6		6
Coupon rate			7.00%
Probability of default			100.00%
Projected recovery rate			0.00%
Probability percentage assigned to default bank subject to market indicators			10.00%
Probability percentage assigned to default bank			100.00%
Federal Home Loan Bank Stock	$ 58,087,000		$ 58,087,000		62,952,000
Investment Securities in Unrealized Loss Position, Qualitative Disclosure, Number of Positions, Total	19		19
Minimum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Subordinated tranches range	7.00%		7.00%
Total principal amount of the respective securities	5.00%		5.00%
Excess subordination as a percentage of current performing collateral			2.00%
Probabilities for performing collateral range			0.33%
Excess present value of future cash flows over our current book value			20.00%
Maximum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Subordinated tranches range	35.00%		35.00%
Excess subordination as a percentage of current performing collateral			82.00%
Probabilities for performing collateral range			75.00%
Excess present value of future cash flows over our current book value			127.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Percent of Unrealized Losses	98.00%		98.00%
Securities available for sale, at fair value	$ 33,723,000		$ 33,723,000		35,658,000
Trust preferred collateralized debt obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other than temporary impairment charges recognized			$ 0	$ 0
Percentage of Current Performing Collateral	0.00%		0.00%
Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities available for sale, at fair value	$ 6,422,000		$ 6,422,000		2,319,000
Pooled Trust Preferred Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other than temporary impairment charges recognized	0	$ 0
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other than temporary impairment charges recognized	0	$ 0
Continuous Unrealized Loss Position, Fair Value	0		0		0
Asset Size and Coupon Rate 1 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Collateral issued by financial institutions	15,000,000,000		$ 15,000,000,000
Coupon rate			7.00%
Prepayment rate			100.00%
Asset Size and Coupon Rate 2 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Coupon rate			7.00%
Fair Value Inputs , Prepayment Rate Year One and Two			40.00%
Fair Value Inputs , Prepayment Rate After Year Two			2.00%
Asset Size and Coupon Rate 3 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Prepayment rate			5.00%
Asset Size and Coupon Rate 3 [Member] | Minimum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Collateral issued by financial institutions	2,000,000,000		$ 2,000,000,000
Asset Size and Coupon Rate 3 [Member] | Maximum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Collateral issued by financial institutions	15,000,000,000		15,000,000,000
Asset Size and Coupon Rate 4 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Collateral issued by financial institutions	$ 2,000,000,000		$ 2,000,000,000
Coupon rate			10.00%
Prepayment rate			5.00%
Asset Size and Coupon Rate 5 [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Prepayment rate			0.00%
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Percent of Unrealized Losses	2.00%		2.00%
Reported Value Measurement [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Securities available for sale, at fair value	$ 855,333,000		$ 855,333,000		$ 886,560,000
Federal Home Loan Bank Stock	$ 58,087,000		$ 58,087,000

Impairment of Investment Secu49

Impairment of Investment Securities - Schedule of Unrealized Losses and Estimated Fair Values (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 15,227	$ 493,938
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	(3,881)
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	92,992	293,076
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(9,748)	(14,910)
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total	108,219	787,014
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss	(9,761)	(18,791)
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		6,798
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(20)
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total		6,798
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		(20)
US Government Agency Debt Securities Commercial [Domain]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		16,596
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(247)
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total		16,596
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		(247)
Residential Mortgage Backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	15,227	436,011
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)	(3,293)
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	64,716	263,119
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(221)	(7,413)
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total	79,943	699,130
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (234)	(10,706)
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		15,009
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		178
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total		15,009
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		178
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		12,316
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(85)
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total		12,316
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		(85)
Obligations of States and Political Subdivisions [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		7,208
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(58)
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total		7,208
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		(58)
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Percent of Unrealized Losses	98.00%
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 0	0
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	28,276	29,957
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(9,527)	(7,497)
Investment Securities, Continuous Unrealized Loss Position, Fair Value, Total	28,276	29,957
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (9,527)	$ (7,497)

Impairment of Investment Secu50

Impairment of Investment Securities - Pooled Trust Preferred Collateralized Debt Obligations (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)Bank	Dec. 31, 2015USD ($)
Impairment Of Investment Securities [Line Items]
Securities available for sale, at fair value	$ 855,333	$ 886,560
Unrealized Gain (Loss)	9,761	$ 16,477
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Impairment Of Investment Securities [Line Items]
Book Value	42,750
Securities available for sale, at fair value	33,723
Unrealized Gain (Loss)	(9,027)
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL IV [Member]
Impairment Of Investment Securities [Line Items]
Book Value	1,830
Securities available for sale, at fair value	1,301
Unrealized Gain (Loss)	$ (529)
Debt Instrument, Credit Rating	B1/BB
Number of Banks (in banks) | Bank	6
Deferrals and Defaults as a % of Current Collateral	18.05%
Excess Subordination as a % of Current Performing Collateral	58.51%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL VII [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 3,061
Securities available for sale, at fair value	3,324
Unrealized Gain (Loss)	$ 263
Debt Instrument, Credit Rating	Ca/-
Number of Banks (in banks) | Bank	14
Deferrals and Defaults as a % of Current Collateral	49.68%
Excess Subordination as a % of Current Performing Collateral	0.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL VIII [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 2,042
Securities available for sale, at fair value	1,691
Unrealized Gain (Loss)	$ (351)
Debt Instrument, Credit Rating	C/C
Number of Banks (in banks) | Bank	28
Deferrals and Defaults as a % of Current Collateral	53.00%
Excess Subordination as a % of Current Performing Collateral	0.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL IX [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 2,394
Securities available for sale, at fair value	1,797
Unrealized Gain (Loss)	$ (597)
Debt Instrument, Credit Rating	B1/C
Number of Banks (in banks) | Bank	38
Deferrals and Defaults as a % of Current Collateral	29.80%
Excess Subordination as a % of Current Performing Collateral	9.73%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL X [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 1,675
Securities available for sale, at fair value	1,817
Unrealized Gain (Loss)	$ 142
Debt Instrument, Credit Rating	Caa1/C
Number of Banks (in banks) | Bank	43
Deferrals and Defaults as a % of Current Collateral	32.22%
Excess Subordination as a % of Current Performing Collateral	2.20%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL XII [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 5,786
Securities available for sale, at fair value	4,442
Unrealized Gain (Loss)	$ (1,344)
Debt Instrument, Credit Rating	B3/C
Number of Banks (in banks) | Bank	66
Deferrals and Defaults as a % of Current Collateral	22.03%
Excess Subordination as a % of Current Performing Collateral	0.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL XIII [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 12,828
Securities available for sale, at fair value	9,971
Unrealized Gain (Loss)	$ (2,857)
Debt Instrument, Credit Rating	Ba3/C
Number of Banks (in banks) | Bank	56
Deferrals and Defaults as a % of Current Collateral	11.34%
Excess Subordination as a % of Current Performing Collateral	47.86%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | Pre TSL XIV [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 12,924
Securities available for sale, at fair value	9,075
Unrealized Gain (Loss)	$ (3,849)
Debt Instrument, Credit Rating	B1/CC
Number of Banks (in banks) | Bank	56
Deferrals and Defaults as a % of Current Collateral	15.21%
Excess Subordination as a % of Current Performing Collateral	38.08%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Mezzanine [Member] | MMCap I [Member]
Impairment Of Investment Securities [Line Items]
Book Value	$ 210
Securities available for sale, at fair value	305
Unrealized Gain (Loss)	$ 95
Debt Instrument, Credit Rating	Ca/C
Number of Banks (in banks) | Bank	8
Deferrals and Defaults as a % of Current Collateral	58.11%
Excess Subordination as a % of Current Performing Collateral	81.96%

Impairment of Investment Secu51

Impairment of Investment Securities - Cumulative Roll Forward of Credit Losses Recognized in Earnings for Debt Securities Held and Not Intended to be Sold (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016		Jun. 30, 2015
Impairment of Investment Securities Disclosure [Abstract]
Balance, beginning (a)	$ 24,590	$ 25,707	$ 24,851	[1]	$ 26,246	[1]
Credit losses on debt securities for which other-than-temporary impairment was not previously recognized	0	0	0		0
Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized	0	0	0		0
Balance, ending	24,310	25,366	24,310		25,366
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Cash Flows	0	0	0		218
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Period Increase (Decrease)	$ 280	$ 341	$ 541		$ 662
[1]	The beginning balance represents credit related losses included in other-than-temporary impairment charges recognized on debt securities in prior periods.

Loans and Allowance for Credi52

Loans and Allowance for Credit Losses - Outstanding Balances of Loan (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 4,843,776	$ 4,683,750	$ 4,490,854
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,185,062	1,150,906	1,098,019
Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	242,132	220,736	125,010
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,199,005	1,224,465	1,204,499
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,648,222	1,479,000	1,416,841
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 569,355	$ 608,643	$ 646,485

Loans and Allowance for Credi53

Loans and Allowance for Credit Losses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due			90 days
Default Status Of TDRs After Number Of Days Past Due			90 days
Charge-offs	$ 6,138	$ 4,952	$ 9,646	$ 12,061
Unfunded commitments related to nonperforming loans	2,200		2,200		$ 100
Off balance sheet reserve to nonperforming loans	0		0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0	0
Total gains or losses included in earnings	0	0	0	105
Nonaccrual	48,076		48,076		36,705
Recorded investment	64,408		$ 64,408		$ 50,844
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non Accrual Status Of Loans After Number Of Days Past Due			150 days
Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans with modifications to rate and payment due to reamortization	300	$ 100	$ 4,200	$ 400
Non Accrual Loans [Member] | Steel and Aluminum Servicing Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	11,400		11,400
Non Accrual Loans [Member] | Coal Industry Manufacturer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	10,500		10,500
Non Accrual Loans [Member] | Oil and Gas Well Services Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	4,400		4,400
Charge-off recognized			2,000
Non Accrual Loans [Member] | Industrial Manufacturer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	3,500		3,500
Charge-off recognized			200
Non Accrual Loans [Member] | Local Energy Company [Member] [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	3,700		3,700
2012 Troubled Debt Restructuring [Member] | Non Accrual Loans [Member] | Local Energy Company [Member] [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	1,300		1,300
Charge-off recognized			1,100
2014 Troubled Debt Restructuring [Member] | Non Accrual Loans [Member] | Local Energy Company [Member] [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	$ 2,400		$ 2,400

Loans and Allowance for Credi54

Loans and Allowance for Credit Losses - Credit Risk Profile by Creditworthiness (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 4,843,776	$ 4,683,750	$ 4,490,854
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	4,715,496	4,549,787
OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	26,282	47,523
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	101,998	86,440
Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Criticized [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	128,280	133,963
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,185,062	1,150,906
Commercial, financial, agricultural and other [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,095,516	1,074,858
Commercial, financial, agricultural and other [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	11,923	11,825
Commercial, financial, agricultural and other [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	77,623	64,223
Commercial, financial, agricultural and other [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Commercial, financial, agricultural and other [Member] | Criticized [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	89,546	76,048
Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	242,132	220,736
Real estate construction [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	241,840	220,267
Real estate construction [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	292	442
Real estate construction [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	27
Real estate construction [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Real estate construction [Member] | Criticized [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	292	469
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,199,005	1,224,465
Residential real estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,183,847	1,209,606
Residential real estate [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	6,846	5,244
Residential real estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	8,312	9,615
Residential real estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Residential real estate [Member] | Criticized [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	15,158	14,859
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,648,222	1,479,000
Commercial Real Estate [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	1,625,206	1,436,714
Commercial Real Estate [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	7,221	30,012
Commercial Real Estate [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	15,795	12,274
Commercial Real Estate [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Commercial Real Estate [Member] | Criticized [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	23,016	42,286
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	569,355	608,643
Loans to individuals [Member] | Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	569,087	608,342
Loans to individuals [Member] | OAEM [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Loans to individuals [Member] | Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	268	301
Loans to individuals [Member] | Doubtful [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	0	0
Loans to individuals [Member] | Criticized [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Net of Deferred Income	$ 268	$ 301

Loans and Allowance for Credi55

Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans by Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	$ 48,076	$ 36,705
Total past due and nonaccrual	62,542	49,636
Current	4,781,234	4,634,114
Total	4,843,776	4,683,750	$ 4,490,854
Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	37,429	23,653
Total past due and nonaccrual	40,770	24,195
Current	1,144,292	1,126,711
Total	1,185,062	1,150,906
Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	0	28
Total past due and nonaccrual	0	308
Current	242,132	220,428
Total	242,132	220,736
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	6,448	6,500
Total past due and nonaccrual	12,777	13,045
Current	1,186,228	1,211,420
Total	1,199,005	1,224,465
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	3,931	6,223
Total past due and nonaccrual	5,098	7,069
Current	1,643,124	1,471,931
Total	1,648,222	1,479,000
Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	268	301
Total past due and nonaccrual	3,897	5,019
Current	565,458	603,624
Total	569,355	608,643
Financing Receivables, 30 to 59 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	10,126	8,598
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	2,344	364
Financing Receivables, 30 to 59 Days Past Due [Member] | Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	0	280
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	4,544	4,175
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	1,166	781
Financing Receivables, 30 to 59 Days Past Due [Member] | Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	2,072	2,998
Financing Receivables, 60 to 89 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	2,956	1,878
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	714	49
Financing Receivables, 60 to 89 Days Past Due [Member] | Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	1,542	1,055
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	700	774
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	1,384	2,455
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial, financial, agricultural and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	283	129
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real estate construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	243	1,315
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	1	65
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Loans to individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due and nonaccrual	$ 857	$ 946

Loans and Allowance for Credi56

Loans and Allowance for Credit Losses - Recorded Investment and Unpaid Principal Balance for Impaired Loans with Associated Allowance (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	$ 34,424		$ 34,424		$ 29,307
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	45,540		45,540		37,565
Impaired Financing Receivable, with Related Allowance, Recorded Investment	29,984		29,984		21,537
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	32,468		32,468		24,270
Related allowance	15,530		15,530		7,045
Recorded investment	64,408		64,408		50,844
Unpaid principal balance	78,008		78,008		61,835
Average recorded investment	24,185	$ 5,759	19,147	$ 5,850
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	37,749	38,862	38,935	41,925
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	216	135	500	251
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	71	43	102	75
Impaired Financing Receivable, Average Recorded Investment	61,934	44,621	58,082	47,775
Interest Income Recognized	287	178	602	326
Commercial, financial, agricultural and other [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	16,078		16,078		11,344
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	23,373		23,373		15,673
Impaired Financing Receivable, with Related Allowance, Recorded Investment	28,522		28,522		20,132
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	30,849		30,849		22,590
Related allowance	15,018		15,018		6,952
Average recorded investment	22,788	5,237	17,939	5,337
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	18,995	18,526	20,116	21,691
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	95	65	249	120
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	65	42	91	72
Real estate construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0		0		28
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	0		0		117
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0		0		0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0		0		0
Related allowance	0		0		0
Average recorded investment	0	0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	0	36	9	137
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	0	0	44	0
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0	0	0
Residential real estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	11,580		11,580		9,952
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	13,674		13,674		11,819
Impaired Financing Receivable, with Related Allowance, Recorded Investment	551		551		461
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	680		680		672
Related allowance	48		48		51
Average recorded investment	476	329	347	319
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	11,462	11,302	11,232	11,025
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	90	45	137	86
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	0	0	0	0
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	6,390		6,390		7,562
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	8,043		8,043		9,449
Impaired Financing Receivable, with Related Allowance, Recorded Investment	911		911		944
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	939		939		1,008
Related allowance	464		464		42
Average recorded investment	921	193	861	194
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	6,887	8,682	7,136	8,760
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	29	24	67	43
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	6	1	11	3
Loans to individuals [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	376		376		421
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	450		450		507
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0		0		0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0		0		0
Related allowance	0		0		$ 0
Average recorded investment	0	0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	405	316	442	312
Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method	2	1	3	2
Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method	$ 0	$ 0	$ 0	$ 0

Loans and Allowance for Credi57

Loans and Allowance for Credit Losses - Troubled Debt Restructured Loans and Commitments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Troubled Debt Restructurings [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 26,004	$ 26,499
Unused lines of Credit [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Loans and Leases Receivable, Impaired, Commitment to Lend	577	3,252
Accrual Loans [Member] [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Financing Receivable, Modifications, Recorded Investment	16,332	14,139
Non Accrual Loans [Member]
Financing Receivable, Troubled Debt Restructurings [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 9,672	$ 12,360

Loans and Allowance for Credi58

Loans and Allowance for Credit Losses - Troubled Debt Restructurings Identified During Period (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)Contract	Jun. 30, 2015USD ($)Contract	Jun. 30, 2016USD ($)Contract	Jun. 30, 2015USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	27	18	42	26
Total Pre-Modification Outstanding Recorded Investment	$ 2,982	$ 952	$ 7,960	$ 3,201
Post- Modification Outstanding Recorded Investment	$ 2,833	$ 898	$ 7,405	$ 3,029
Financing Receivable, Modifications, Determination of Allowance for Credit Losses	114,000	60,000	114,000	60,000
Commercial, financial, agricultural and other [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	4	2	5	3
Total Pre-Modification Outstanding Recorded Investment	$ 332	$ 361	$ 4,101	$ 1,860
Post- Modification Outstanding Recorded Investment	$ 217	$ 317	$ 3,708	$ 1,812
Financing Receivable, Modifications, Determination of Allowance for Credit Losses	40	53	40	53
Residential real estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	17	11	26	16
Total Pre-Modification Outstanding Recorded Investment	$ 1,435	$ 530	$ 2,530	$ 799
Post- Modification Outstanding Recorded Investment	$ 1,428	$ 525	$ 2,440	$ 723
Financing Receivable, Modifications, Determination of Allowance for Credit Losses	0	7	0	7
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	4		6	1
Total Pre-Modification Outstanding Recorded Investment	$ 1,198		$ 1,289	$ 463
Post- Modification Outstanding Recorded Investment	$ 1,173		$ 1,227	$ 428
Financing Receivable, Modifications, Determination of Allowance for Credit Losses	74		74	0
Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	2	5	5	6
Total Pre-Modification Outstanding Recorded Investment	$ 17	$ 61	$ 40	$ 79
Post- Modification Outstanding Recorded Investment	$ 15	$ 56	$ 30	$ 66
Financing Receivable, Modifications, Determination of Allowance for Credit Losses	0	0	0	0
Extended Maturity [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	$ 1,290	$ 252	$ 1,356	$ 1,751
Extended Maturity [Member] | Commercial, financial, agricultural and other [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	92	252	92	1,751
Extended Maturity [Member] | Residential real estate [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	0	0	0	0
Extended Maturity [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	1,198		1,264	0
Extended Maturity [Member] | Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	0	0	0	0
Contractual Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	251	106	4,152	357
Contractual Interest Rate Reduction [Member] | Commercial, financial, agricultural and other [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	240	0	4,009	0
Contractual Interest Rate Reduction [Member] | Residential real estate [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	0	45	114	296
Contractual Interest Rate Reduction [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	0		0	0
Contractual Interest Rate Reduction [Member] | Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	11	61	29	61
Contractual Payment Modification [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	1,441	594	2,452	1,093
Contractual Payment Modification [Member] | Commercial, financial, agricultural and other [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	0	109	0	109
Contractual Payment Modification [Member] | Residential real estate [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	1,435	485	2,416	503
Contractual Payment Modification [Member] | Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	0		25	463
Contractual Payment Modification [Member] | Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Total Pre-Modification Outstanding Recorded Investment	$ 6	$ 0	$ 11	$ 18

Loans and Allowance for Credi59

Loans and Allowance for Credit Losses - Troubled Debt Restructuring is 90 Days or More Past Due (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)Contract	Jun. 30, 2015USD ($)Contract	Jun. 30, 2016USD ($)Contract	Jun. 30, 2015USD ($)Contract
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | Contract	0	2	0	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 0	$ 56	$ 0	$ 56
Residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts | Contract	0	2	0	2
Financing Receivable, Modifications, Subsequent Default, Recorded Investment | $	$ 0	$ 56	$ 0	$ 56

Loans and Allowance for Credi60

Loans and Allowance for Credit Losses - Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	$ 55,222	$ 46,697	$ 50,812	$ 52,051
Charge-offs	(6,138)	(4,952)	(9,646)	(12,061)
Recoveries	365	561	1,757	1,157
Provision for Loan, Lease, and Other Losses	10,372	3,038	16,898	4,197
Ending Balance	55,222	46,697	50,812	52,051	$ 59,821	$ 50,812	$ 45,344
Ending balance: individually evaluated for impaired					15,530		1,675
Ending balance: collectively evaluated for impaired					44,291		43,669
Total					4,843,776	4,683,750	4,490,854
Ending balance: individually evaluated for impaired					55,800		36,744
Ending balance: collectively evaluated for impaired					4,787,976		4,454,110
Commercial, financial, agricultural and other [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	41,721	24,406	31,035	29,627
Charge-offs	(4,753)	(2,860)	(6,145)	(7,940)
Recoveries	64	158	198	358
Provision for Loan, Lease, and Other Losses	9,325	2,051	21,269	1,710
Ending Balance	41,721	24,406	31,035	29,627	46,357	31,035	23,755
Ending balance: individually evaluated for impaired					15,018		1,596
Ending balance: collectively evaluated for impaired					31,339		22,159
Total					1,185,062	1,150,906	1,098,019
Ending balance: individually evaluated for impaired					43,817		21,419
Ending balance: collectively evaluated for impaired					1,141,245		1,076,600
Real estate construction [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	901	1,528	887	2,063
Charge-offs	0	0	0	0
Recoveries	4	84	227	84
Provision for Loan, Lease, and Other Losses	(425)	(94)	(634)	(629)
Ending Balance	901	1,528	887	2,063	480	887	1,518
Ending balance: individually evaluated for impaired					0		0
Ending balance: collectively evaluated for impaired					480		1,518
Total					242,132	220,736	125,010
Ending balance: individually evaluated for impaired					0		0
Ending balance: collectively evaluated for impaired					242,132		125,010
Residential real estate [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	2,628	3,387	2,606	3,664
Charge-offs	(220)	(484)	(602)	(1,050)
Recoveries	142	143	260	239
Provision for Loan, Lease, and Other Losses	55	(123)	341	70
Ending Balance	2,628	3,387	2,606	3,664	2,605	2,606	2,923
Ending balance: individually evaluated for impaired					48		35
Ending balance: collectively evaluated for impaired					2,557		2,888
Total					1,199,005	1,224,465	1,204,499
Ending balance: individually evaluated for impaired					5,966		7,700
Ending balance: collectively evaluated for impaired					1,193,039		1,196,799
Commercial Real Estate [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	5,483	12,487	11,924	11,881
Charge-offs	(143)	(486)	(408)	(688)
Recoveries	27	15	783	153
Provision for Loan, Lease, and Other Losses	495	211	(6,437)	881
Ending Balance	5,483	12,487	11,924	11,881	5,862	11,924	12,227
Ending balance: individually evaluated for impaired					464		44
Ending balance: collectively evaluated for impaired					5,398		12,183
Total					1,648,222	1,479,000	1,416,841
Ending balance: individually evaluated for impaired					6,017		7,625
Ending balance: collectively evaluated for impaired					1,642,205		1,409,216
Loans to individuals [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	4,489	4,889	4,360	4,816
Charge-offs	(1,022)	(1,122)	(2,491)	(2,383)
Recoveries	128	161	289	323
Provision for Loan, Lease, and Other Losses	922	993	2,359	2,165
Ending Balance	$ 4,489	$ 4,889	$ 4,360	$ 4,816	4,517	4,360	4,921
Ending balance: individually evaluated for impaired					0		0
Ending balance: collectively evaluated for impaired					4,517		4,921
Total					569,355	$ 608,643	646,485
Ending balance: individually evaluated for impaired					0		0
Ending balance: collectively evaluated for impaired					$ 569,355		$ 646,485

Fair Values of Assets and Lia61

Fair Values of Assets and Liabilities - Quantitative Inputs and Assumptions Used in Level 3 Fair Value Measurements (Detail) - USD ($)		6 Months Ended
		Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		$ 855,333,000	$ 886,560,000
Assets		$ 948,119,000	966,548,000
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Minimum [Member] | Discount rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	[1]	5.50%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Maximum [Member] | Discount rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate	[1]	12.50%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member] | Minimum [Member] | Probability of default [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		0.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member] | Minimum [Member] | Prepayment rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		0.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member] | Maximum [Member] | Probability of default [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		100.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member] | Maximum [Member] | Prepayment rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		73.03%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member] | Weighted average [Member] | Probability of default [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		11.47%
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Discounted Cash Flow [Member] | Weighted average [Member] | Prepayment rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		5.14%
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		$ 1,670,000	2,170,000
Impaired Loans [Member] | Discounted Cash Flow [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		6,815,000
Impaired Loans [Member] | Discounted Cash Flow [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		0
Impaired Loans [Member] | Discounted Cash Flow [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		$ 0
Impaired Loans [Member] | Discounted Cash Flow [Member] | Weighted average [Member] | Discount rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate
Impaired Loans [Member] | Reserve Study [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		$ 2,414,000
Impaired Loans [Member] | Reserve Study [Member] | NGL per gallon [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Monetary	[2]
Impaired Loans [Member] | Reserve Study [Member] | Minimum [Member] | Gas per MCF [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Monetary	[2]	1.63
Impaired Loans [Member] | Reserve Study [Member] | Minimum [Member] | Oil per BBL/d [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Monetary	[2]	40.97
Impaired Loans [Member] | Reserve Study [Member] | Maximum [Member] | Gas per MCF [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Monetary	[2]	3.38
Impaired Loans [Member] | Reserve Study [Member] | Maximum [Member] | Oil per BBL/d [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs Monetary	[2]	$ 56.16
Impaired Loans [Member] | Reserve Study [Member] | Weighted average [Member] | Discount rates [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average rate		10.00%
Limited Partnership Investment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets		$ 704,000
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		35,393,000	37,828,000
Assets		36,097,000	37,828,000
Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		1,670,000	2,170,000
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		33,723,000	35,658,000
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value			35,658,000
Pooled Trust Preferred Collateralized Debt Obligations [Member] | Level 3 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value		33,723,000
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Real Estate Owned Assets Fair Value		10,036,000	10,047,000
Assets		58,914,000	53,846,000
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Real Estate Owned Assets Fair Value		0	8,000
Assets		18,104,000	$ 12,828,000
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other Real Estate Owned Assets Fair Value		$ 0
[1]	ncorporates spread over risk free rate related primarily to credit quality and illiquidity of securities.(b)The remainder of impaired loans valued using Level 3 inputs are not included in this disclosure as the values of those loans are based on bankruptcy agreement documentation.(c)Unobservable inputs are defined as follows: MCF - million cubic feet; BBL/d - barrels per day.
[2]	nobservable inputs are defined as follows: MCF - million cubic feet; BBL/d - barrels per day.

Fair Values of Assets and Lia62

Fair Values of Assets and Liabilities - Schedule of Changes in Level 3 Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	$ (536)		$ (536)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	35,479	$ 33,054	37,828	$ 30,419
Total gains or losses included in earnings	0	0	0	105
Total gains or losses included in other comprehensive income	480	4,851	(1,905)	7,471
Purchases	168	0	204	500
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	30	464	(30)	(1,054)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	536	0	536	0
Balance, end of period	36,097	37,441	36,097	37,441
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	33,273	31,134	35,658	28,999
Total gains or losses included in earnings	0	0	0	105
Total gains or losses included in other comprehensive income	480	4,851	(1,905)	7,471
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	30	464	(30)	(1,054)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	0	0	0
Balance, end of period	33,723	35,521	33,723	35,521
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	536		536
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	2,206	1,920	2,170	1,420
Total gains or losses included in earnings	0	0	0	0
Total gains or losses included in other comprehensive income	0	0	0	0
Purchases	0	0	36	500
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	0	0	0
Balance, end of period	1,670	$ 1,920	1,670	$ 1,920
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0		0
Total gains or losses included in earnings	0		0
Total gains or losses included in other comprehensive income	0		0
Purchases	168		168
Issuances	0		0
Sales	0		0
Settlements	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	536		536
Balance, end of period	$ 704		$ 704

Fair Values of Assets and Lia63

Fair Values of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016		Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	$ 855,333		$ 886,560
Other investments	58,087		62,952
Loans Held for Sale	11,613		5,763
Other Assets	23,086	[1]	11,273	[2]
Total Assets	948,119		966,548
Other Liabilities	21,405	[1]	10,829	[2]
Total Liabilities	21,405		10,829
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	853,663		884,390
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	1,670		2,170
US Government Agencies Residential Mortgage-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	18,762		22,092
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	747,396		777,577
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	2		28
Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	19,322		19,118
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	28,036		27,598
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	6,422		2,319
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	33,723		35,658
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Other investments	0		0
Loans Held for Sale	0		0
Other Assets	0	[1]	0	[2]
Total Assets	0		0
Other Liabilities	0	[1]	0	[2]
Total Liabilities	0		0
Level 1 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | US Government Agencies Residential Mortgage-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 1 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	819,940		848,732
Other investments	58,087		62,952
Loans Held for Sale	11,613		5,763
Other Assets	22,382	[1]	11,273	[2]
Total Assets	912,022		928,720
Other Liabilities	21,405	[1]	10,829	[2]
Total Liabilities	21,405		10,829
Level 2 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	819,940		848,732
Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 2 [Member] | US Government Agencies Residential Mortgage-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	18,762		22,092
Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	747,396		777,577
Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	2		28
Level 2 [Member] | Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	19,322		19,118
Level 2 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	28,036		27,598
Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	6,422		2,319
Level 2 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	35,393		37,828
Other investments	0		0
Loans Held for Sale	0		0
Other Assets	704	[1]	0	[2]
Total Assets	36,097		37,828
Other Liabilities	0	[1]	0	[2]
Total Liabilities	0		0
Level 3 [Member] | Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	33,723		35,658
Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	1,670		2,170
Level 3 [Member] | US Government Agencies Residential Mortgage-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 3 [Member] | Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 3 [Member] | Obligations of U.S. Government-Sponsored Enterprises - Other Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 3 [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	0		0
Level 3 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value	$ 0		0
Level 3 [Member] | Pooled Trust Preferred Collateralized Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale, at fair value			$ 35,658
[1]	Hedging and non-hedging interest rate derivatives
[2]	on-hedging interest rate derivatives

Fair Values of Assets and Lia64

Fair Values of Assets and Liabilities - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Assets, Level 1 to Level 2 Transfers, Description	$ 0		$ 0		$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	536,000	$ 0	536,000	$ 0
Impaired loans considered to be credit risk of non-collection	100,000		100,000
Updated appraisal requirement floor	250,000		250,000
Other real estate owned	8,604,000		8,604,000		9,398,000
Financial instrument of credit risk	200,000		200,000		$ 200,000
Fair Value, Assets Measured on Recurring Basis, Gain (Loss) Included in Other Income, Assets and Liabilities Continue to be held			0	$ 0
Other Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	$ 536,000		$ 536,000
Minimum [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Swap Rates Term Used to Determine Yield Curve			3 years
Maximum [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Swap Rates Term Used to Determine Yield Curve			30 years

Fair Values of Assets and Lia65

Fair Values of Assets and Liabilities - Schedule of Assets Measured on Non-Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	$ 948,119	$ 966,548
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	48,878	43,799
Other real estate owned	10,036	10,047
Total Assets	58,914	53,846
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	0	0
Level 1 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate owned	0	0
Total Assets	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	912,022	928,720
Level 2 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	30,774	30,979
Other real estate owned	10,036	10,039
Total Assets	40,810	41,018
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Assets	36,097	37,828
Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	18,104	12,820
Other real estate owned	0	8
Total Assets	$ 18,104	$ 12,828

Fair Values of Assets and Lia66

Fair Values of Assets and Liabilities - Losses Realized on Assets Measured on Non-Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Impaired loans	$ (6,991)	$ (382)	$ (14,576)	$ (843)
Other real estate owned	(245)	(1,126)	(258)	(1,154)
Total losses	$ (7,236)	$ (1,508)	$ (14,834)	$ (1,997)

Fair Values of Assets and Lia67

Fair Values of Assets and Liabilities - Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Carrying Amount [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	$ 68,163	$ 66,644
Interest-bearing deposits	30,457	2,808
Securities available for sale, at fair value	855,333	886,560
Held-to-maturity Securities	405,976
Other investments	58,087
Loans Held for sale, Amount	11,613	5,763
Loans and Leases Receivable, Net of Deferred Income	4,843,776	4,683,750
Deposits	4,394,520	4,195,894
Short-term borrowings	1,464,687	1,510,825
Subordinated debt	72,167	72,167
Long-term debt	9,034	9,314
Estimate of Fair Value Measurement [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	68,163	66,644
Interest-bearing deposits	30,457	2,808
Securities available for sale, at fair value	855,333	886,560
Held-to-maturity Securities	414,770
Other investments	58,087	62,952
Loans Held for sale, Amount	11,613	5,763
Loans and Leases Receivable, Net of Deferred Income	4,857,127	4,690,852
Deposits	4,395,297	4,198,817
Short-term borrowings	1,464,408	1,510,718
Subordinated debt	61,427	62,794
Long-term debt	10,077	9,834
Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	68,163	66,644
Interest-bearing deposits	30,457	2,808
Securities available for sale, at fair value	0	0
Held-to-maturity Securities	0
Other investments	0	0
Loans Held for sale, Amount	0	0
Loans and Leases Receivable, Net of Deferred Income	0	0
Deposits	0	0
Short-term borrowings	0	0
Subordinated debt	0	0
Long-term debt	0	0
Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Securities available for sale, at fair value	819,940	848,732
Held-to-maturity Securities	414,770
Other investments	58,087	62,952
Loans Held for sale, Amount	11,613	5,763
Loans and Leases Receivable, Net of Deferred Income	30,774	30,979
Deposits	4,395,297	4,198,817
Short-term borrowings	1,464,408	1,510,718
Subordinated debt	0	0
Long-term debt	10,077	9,834
Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Securities available for sale, at fair value	35,393	37,828
Held-to-maturity Securities	0
Other investments	0	0
Loans Held for sale, Amount	0	0
Loans and Leases Receivable, Net of Deferred Income	4,826,353	4,659,873
Deposits	0	0
Short-term borrowings	0	0
Subordinated debt	61,427	62,794
Long-term debt	$ 0	$ 0

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)Derivatives	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)Derivatives	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Risk participation Agreements [Line Items]
HedgedItemsOfCashFlowHedge	$ 200,000		$ 200,000
Derivative Instruments Designated As Hedging Instruments Interest Income	$ 424	$ 557	$ 854	$ 938
Risk Participation Agreements Purchased [Domain]
Risk participation Agreements [Line Items]
Number of interest rate swaps | Derivatives	22		22
Risk Participation Agreements Sold [Domain]
Risk participation Agreements [Line Items]
Number of interest rate swaps | Derivatives	7		7
Designated as Hedging Instrument [Member]
Risk participation Agreements [Line Items]
Derivative, Notional Amount	$ 200,000		$ 200,000		$ 200,000
Three Year Maturity [Member] | Designated as Hedging Instrument [Member]
Risk participation Agreements [Line Items]
Derivative, Notional Amount	85,000		85,000
Four Year Maturity [Member] | Designated as Hedging Instrument [Member]
Risk participation Agreements [Line Items]
Derivative, Notional Amount	$ 115,000		$ 115,000

Derivatives - Credit Value Adju

Derivatives - Credit Value Adjustment Recorded Related to Notional Amount of Derivatives Outstanding (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	$ (2,075)	$ (542)
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	(3,015)	922
Derivative, Notional Amount	200,000	200,000
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	324,630	276,860
Interest Rate Cap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	21,168	22,793
Credit Default Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	164,850	126,612
Credit Default Swap, Selling Protection [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ (35,786)	$ (20,383)

Derivatives - Schedule of Chang

Derivatives - Schedule of Changes in Fair Value of Derivative Assets and Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (531)	$ 593	$ (1,545)	$ 363
Derivative Instruments Designated As Hedging Instruments Interest Income	424	557	854	938
Derivative, Net Hedge Ineffectiveness Gain (Loss)	$ 26	$ 12	$ 41	$ 21

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Goodwill Disclosure [Abstract]
Goodwill	$ 164,500,000		$ 164,500,000
Impairment charges on goodwill	$ 0	$ 0

Subsequent Event (Details)

Subsequent Event (Details) $ in Millions	Jun. 30, 2016USD ($)branch
Subsequent Events [Abstract]
Branch Acquisition, Number of Branches | branch	13
Branch Acquisition, Total Deposits	$ 735
Branch Acquisition, Total Loans	$ 115