WesBanco (WSBC) 10-Q 30 Apr 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 23, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Trading Symbol	WSBC
Entity Registrant Name	WESBANCO INC
Entity Central Index Key	203,596
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		46,568,911

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks, including interest bearing amounts of $9,484 and $19,826, respectively	$ 100,845	$ 117,572
Securities:
Equity securities, at fair value	13,986	13,457
Available-for-sale debt securities, at fair value	1,728,377	1,261,865
Held-to-maturity debt securities (fair values of $1,005,502 and $1,023,784, respectively)	1,006,042	1,009,500
Total securities	2,748,405	2,284,822
Loans held for sale	12,962	20,320
Portfolio loans, net of unearned income	6,322,538	6,341,441
Allowance for loan losses	(46,334)	(45,284)
Net portfolio loans	6,276,204	6,296,157
Premises and equipment, net	128,583	130,722
Accrued interest receivable	31,963	29,728
Goodwill and other intangible assets, net	588,339	589,264
Bank-owned life insurance	191,839	192,589
Other assets	166,279	155,004
Total Assets	10,245,419	9,816,178
Deposits:
Non-interest bearing demand	1,950,619	1,846,748
Interest bearing demand	1,768,977	1,625,015
Money market	984,429	1,024,856
Savings deposits	1,314,632	1,269,912
Certificates of deposit	1,207,669	1,277,057
Total deposits	7,226,326	7,043,588
Federal Home Loan Bank borrowings	1,166,939	948,203
Other short-term borrowings	207,653	184,805
Subordinated debt and junior subordinated debt	164,379	164,327
Total borrowings	1,538,971	1,297,335
Accrued interest payable	4,033	3,178
Other liabilities	73,063	76,756
Total Liabilities	8,842,393	8,420,857
SHAREHOLDERS' EQUITY
Preferred stock, no par value; 1,000,000 shares authorized; none outstanding
Common stock, $2.0833 par value; 100,000,000 shares authorized in 2018 and 2017, respectively; 44,060,957 and 44,043,244 shares issued, respectively; 44,060,957 and 44,043,244 shares outstanding, respectively	91,793	91,756
Capital surplus	686,169	684,730
Retained earnings	673,174	651,357
Treasury stock (0 shares in 2018 and 2017, respectively, at cost)	0	0
Accumulated other comprehensive loss	(47,076)	(31,495)
Deferred benefits for directors	(1,034)	(1,027)
Total Shareholders' Equity	1,403,026	1,395,321
Total Liabilities and Shareholders' Equity	$ 10,245,419	$ 9,816,178

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Interest bearing deposits, banks	$ 9,484	$ 19,826
Held-to-maturity securities, fair values	$ 1,005,502	$ 1,023,784
Preferred stock, no par value
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 2.0833	$ 2.0833
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	44,060,957	44,043,244
Common stock, shares outstanding	44,060,957	44,043,244
Treasury stock, shares	0	0

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
INTEREST AND DIVIDEND INCOME
Loans, including fees	$ 69,237	$ 64,898
Interest and dividends on securities:
Taxable	11,543	9,596
Tax-exempt	4,834	4,891
Total interest and dividends on securities	16,377	14,487
Other interest income	803	539
Total interest and dividend income	86,417	79,924
INTEREST EXPENSE
Interest bearing demand deposits	2,524	1,093
Money market deposits	878	574
Savings deposits	189	181
Certificates of deposit	2,536	2,411
Total interest expense on deposits	6,127	4,259
Federal Home Loan Bank borrowings	4,498	2,836
Other short-term borrowings	558	297
Subordinated debt and junior subordinated debt	1,942	1,813
Total interest expense	13,125	9,205
NET INTEREST INCOME	73,292	70,719
Provision for credit losses	2,168	2,711
Net interest income after provision for credit losses	71,124	68,008
NON-INTEREST INCOME
Trust fees	6,503	6,143
Service charges on deposits	4,822	4,853
Electronic banking fees	4,829	4,528
Net securities brokerage revenue	1,670	1,762
Bank-owned life insurance	2,756	1,140
Mortgage banking income	1,004	1,440
Net securities (losses) gains	(39)	12
Net gain (loss) on other real estate owned and other assets	262	(76)
Other income	2,173	3,082
Total non-interest income	23,980	22,884
NON-INTEREST EXPENSE
Salaries and wages	25,006	23,002
Employee benefits	6,912	8,210
Net occupancy	4,656	4,327
Equipment	3,949	4,042
Marketing	1,116	824
FDIC insurance	658	827
Amortization of intangible assets	1,086	1,273
Restructuring and merger-related expense	245	491
Other operating expenses	10,943	11,388
Total non-interest expense	54,571	54,384
Income before provision for income taxes	40,533	36,508
Provision for income taxes	7,004	10,622
NET INCOME	$ 33,529	$ 25,886
EARNINGS PER COMMON SHARE
Basic	$ 0.76	$ 0.59
Diluted	$ 0.76	$ 0.59
AVERAGE COMMON SHARES OUTSTANDING
Basic	44,050,701	43,947,563
Diluted	44,168,242	44,020,765
DIVIDENDS DECLARED PER COMMON SHARE	$ 0.29	$ 0.26
COMPREHENSIVE INCOME	$ 19,011	$ 28,171

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Deferred Benefits for Directors [Member]
Beginning Balance at Dec. 31, 2016	$ 1,341,408	$ 91,524	$ 680,507	$ 597,071	$ (27,126)	$ (568)
Beginning Balance, shares at Dec. 31, 2016		43,931,715
Net income	25,886			25,886
Other comprehensive income	2,285				2,285
Comprehensive income	28,171
Common dividends declared ($0.26 per share)	(11,429)			(11,429)
Stock options exercised	526	$ 36	490
Stock options exercised, shares		17,634
Restricted stock granted		$ 8	(8)
Restricted stock granted, shares		3,702
Stock compensation expense	477		477
Deferred benefits for directors - net			5			(5)
Ending Balance at Mar. 31, 2017	1,359,153	$ 91,568	681,471	611,528	(24,841)	(573)
Ending Balance, shares at Mar. 31, 2017		43,953,051
Beginning Balance at Dec. 31, 2017	1,395,321	$ 91,756	684,730	651,357	(31,495)	(1,027)
Beginning Balance, shares at Dec. 31, 2017		44,043,244
Net income	33,529			33,529
Other comprehensive income	(14,518)				(14,518)
Comprehensive income	19,011
Common dividends declared ($0.26 per share)	(12,775)			(12,775)
Adoption of accounting standard ASU 2016-01				1,063	(1,063)
Stock options exercised	560	$ 37	523
Stock options exercised, shares		17,713
Stock compensation expense	909		909
Deferred benefits for directors - net			7			(7)
Ending Balance at Mar. 31, 2018	$ 1,403,026	$ 91,793	$ 686,169	$ 673,174	$ (47,076)	$ (1,034)
Ending Balance, shares at Mar. 31, 2018		44,060,957

Consolidated Statements of Cha6

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Stockholders' Equity [Abstract]
Common dividends declared, per share	$ 0.29	$ 0.26

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Cash Flows [Abstract]
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 32,371	$ 47,508
INVESTING ACTIVITIES
Net decrease (increase) in loans held for investment	19,923	(63,701)
Debt securities available-for-sale:
Proceeds from maturities, prepayments and calls	53,496	59,043
Purchases of securities	(540,624)	(41,742)
Debt securities held-to-maturity:
Proceeds from maturities, prepayments and calls	17,121	24,367
Purchases of securities	(15,343)	(16,023)
Equity securities:
Purchases of securities	(558)
Proceeds from bank-owned life insurance	3,506
Purchases of premises and equipment-net	(328)	(2,311)
Net cash used in investing activities	(462,807)	(40,367)
FINANCING ACTIVITIES
Increase in deposits	183,012	105,344
Proceeds from Federal Home Loan Bank borrowings	375,000	170,000
Repayment of Federal Home Loan Bank borrowings	(156,261)	(201,825)
Increase (decrease) in other short-term borrowings	27,848	(25,733)
Decrease in federal funds purchased	(5,000)	(58,000)
Dividends paid to common shareholders	(11,450)	(10,539)
Issuance of common stock	560	526
Net cash provided by (used in) financing activities	413,709	(20,227)
Net decrease in cash and cash equivalents	(16,727)	(13,086)
Cash and cash equivalents at beginning of the period	117,572	128,170
Cash and cash equivalents at end of the period	100,845	115,084
SUPPLEMENTAL DISCLOSURES
Interest paid on deposits and other borrowings	$ 12,496	9,441
Income taxes paid		250
Transfers of loans to other real estate owned		$ 77

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of presentation — 10-Q S-X. 10-K WesBanco’s interim financial statements have been prepared following the significant accounting policies disclosed in Note 1 of the Notes to the Consolidated Financial Statements of its 2017 Annual Report on Form 10-K Recent accounting pronouncements — No. 2017-12, 2017-12 In March 2017, the FASB issued ASU 2017-07 non-interest In January 2017, the FASB issued ASU No. 2017-01, 2017-01 In October 2016, the FASB issued ASU 2016-16 In August 2016, the FASB issued ASU 2016-15 zero-coupon In June 2016, the FASB issued ASU 2016-13 held-to-maturity available-for-sale In February 2016, the FASB issued ASU 2016-02 2018-01, non-cancellable In January 2016, the FASB issued ASU 2016-01 2018-03, 2016-01. available-for-sale held-to-maturity In May 2014, the FASB issued ASU 2014-09 one-year 2016-08, 2016-10, 2016-12,

Earnings Per Common Share

Earnings Per Common Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	NOTE 2. EARNINGS PER COMMON SHARE Earnings per common share are calculated as follows: For the Three Months Ended (unaudited, in thousands, except shares and per share amounts) 2018 2017 Numerator for both basic and diluted earnings per common share: Net income $ 33,529 $ 25,886 Denominator: Total average basic common shares outstanding 44,050,701 43,947,563 Effect of dilutive stock options and other stock compensation 117,541 73,202 Total diluted average common shares outstanding 44,168,242 44,020,765 Earnings per common share – basic $ 0.76 $ 0.59 Earnings per common share – diluted $ 0.76 $ 0.59 All options to purchase shares were included in the diluted shares computation for the three months ended March 31, 2018 and March 31, 2017. As of March 31, 2018, contingently issuable shares, totaling 39,216, were estimated to be awarded under the 2018, 2017 and 2016 total shareholder return plans as stock performance targets were met and are included in the diluted calculation. As of March 31, 2017, the shares related to the 2017 and 2016 total shareholder return plans were not included in the calculation because the effect would be antidilutive. Performance based restricted stock compensation totaling 9,000 shares were estimated to be awarded as of March 31, 2018 and are included in the diluted calculation. No performance base restricted stock had been granted as of March 31, 2017.

Securities

Securities	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	NOTE 3. SECURITIES The following table presents the fair value and amortized cost of available-for-sale held-to-maturity March 31, 2018 December 31, 2017 (unaudited, in thousands) Amortized Gross Gross Estimated Value Amortized Gross Gross Estimated Value Available-for-sale U.S. Treasury $ 9,900 $ — $ (6 ) $ 9,894 $ — $ — $ — $ — U.S. Government sponsored entities and agencies 98,166 1 (1,709 ) 96,458 72,425 24 (606 ) 71,843 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 1,377,904 214 (33,708 ) 1,344,410 954,115 214 (19,407 ) 934,922 Commerical mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 144,568 19 (3,661 ) 140,926 116,448 4 (1,585 ) 114,867 Obligations of states and political subdivisions 100,531 2,093 (1,193 ) 101,431 102,363 2,927 (460 ) 104,830 Corporate debt securities 35,219 170 (131 ) 35,258 35,234 228 (59 ) 35,403 Total available-for-sale $ 1,766,288 $ 2,497 $ (40,408 ) $ 1,728,377 $ 1,280,585 $ 3,397 $ (22,117 ) $ 1,261,865 Held-to-maturity U.S. Government sponsored entities and agencies $ 11,263 $ — $ (373 ) $ 10,890 $ 11,465 $ — $ (325 ) $ 11,140 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 162,904 301 (4,987 ) 158,218 170,025 544 (2,609 ) 167,960 Obligations of states and political subdivisions 798,536 10,510 (5,838 ) 803,208 794,655 17,364 (1,609 ) 810,410 Corporate debt securities 33,339 82 (235 ) 33,186 33,355 919 — 34,274 Total held-to-maturity $ 1,006,042 $ 10,893 $ (11,433 ) $ 1,005,502 $ 1,009,500 $ 18,827 $ (4,543 ) $ 1,023,784 Total debt securities $ 2,772,330 $ 13,390 $ (51,841 ) $ 2,733,879 $ 2,290,085 $ 22,224 $ (26,660 ) $ 2,285,649 At March 31, 2018, and December 31, 2017, there were no holdings of any one issuer, other than U.S. government sponsored entities and its agencies, in an amount greater than 10% of WesBanco’s shareholders’ equity. Equity securities, of which some consist of investments in various mutual funds held in grantor trusts formed in connection with the Company’s deferred compensation plan, are recorded at fair value and totaled $14.0 million and $13.5 million, at March 31, 2018 and December 31, 2017, respectively. The following table presents the fair value of available-for-sale held-to-maturity March 31, 2018 (unaudited, in thousands) One Year or less One to Five Years Five to Ten Years After Ten Years Mortgage-backed securities Total Available-for-sale U.S. Treasury $ 9,894 $ — $ — $ — $ — $ 9,894 U.S. Government sponsored entities and agencies 9,945 1,961 16,671 6,864 61,017 96,458 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 1,344,410 1,344,410 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 140,926 140,926 Obligations of states and political subdivisions 3,686 17,368 40,161 40,216 — 101,431 Corporate debt securities 3,991 26,299 4,968 — — 35,258 Total available-for-sale $ 27,516 $ 45,628 $ 61,800 $ 47,080 $ 1,546,353 $ 1,728,377 Held-to-maturity (2) U.S. Government sponsored entities and agencies $ — $ — $ — $ — $ 10,890 $ 10,890 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — 158,218 158,218 Obligations of states and political subdivisions 6,872 114,768 398,845 282,723 — 803,208 Corporate debt securities — 7,504 25,682 — — 33,186 Total held-to-maturity $ 6,872 $ 122,272 $ 424,527 $ 282,723 $ 169,108 $ 1,005,502 Total debt securities $ 34,388 $ 167,900 $ 486,327 $ 329,803 $ 1,715,461 $ 2,733,879 (1) Mortgage-backed and collateralized mortgage securities, which have prepayment provisions, are not assigned to maturity categories due to fluctuations in their prepayment speeds. (2) The held-to-maturity Securities with aggregate fair values of $1.5 billion and $1.4 billion at March 31, 2018 and December 31, 2017, respectively, were pledged as security for public and trust funds, and securities sold under agreements to repurchase. There were no sales of available-for-sale available-for-sale The following table presents the gross realized gains and losses on sales and calls of available-for-sale held-to-maturity For the Three Months Ended March 31, (unaudited, in thousands) 2018 2017 Debt securities: Gross realized gains $ 7 $ 12 Gross realized losses (18 ) — Net (losses) gains on debt securities $ (11 ) $ 12 Equity securities: Unrealized (losses) gains recognized on securities still held $ (28 ) $ — Net realized (losses) gains recognized on securities sold — — Net (losses) gains on equity securities $ (28 ) $ — Net securities (losses) gains $ (39 ) $ 12 The following tables provide information on unrealized losses on debt securities that have been in an unrealized loss position for less than twelve months and twelve months or more as of March 31, 2018 and December 31, 2017: March 31, 2018 Less than 12 months 12 months or more Total Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of (unaudited, dollars in thousands) Value Losses Securities Value Losses Securities Value Losses Securities U.S. Treasury $ 9,894 $ (6 ) 1 $ — $ — — $ 9,894 $ (6 ) 1 U.S. Government sponsored entities and agencies 59,280 (1,129 ) 8 41,203 (953 ) 8 100,483 (2,082 ) 16 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 785,806 (13,021 ) 128 602,202 (25,674 ) 195 1,388,008 (38,695 ) 323 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 101,309 (2,780 ) 12 23,376 (881 ) 4 124,685 (3,661 ) 16 Obligations of states and political subdivisions 335,762 (4,776 ) 527 72,751 (2,255 ) 152 408,513 (7,031 ) 679 Corporate debt securities 35,405 (352 ) 12 1,974 (14 ) 1 37,379 (366 ) 13 Total temporarily impaired securities $ 1,327,456 $ (22,064 ) 688 $ 741,506 $ (29,777 ) 360 $ 2,068,962 $ (51,841 ) 1,048 December 31, 2017 Less than 12 months 12 months or more Total Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of (unaudited, dollars in thousands) Value Losses Securities Value Losses Securities Value Losses Securities U.S. Government sponsored entities and agencies $ 24,776 $ (160 ) 4 $ 42,248 $ (771 ) 8 $ 67,024 $ (931 ) 12 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 423,794 (5,039 ) 87 637,461 (16,977 ) 193 1,061,255 (22,016 ) 280 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 79,061 (1,089 ) 10 27,852 (496 ) 6 106,913 (1,585 ) 16 Obligations of states and political subdivisions 132,831 (852 ) 210 77,554 (1,217 ) 160 210,385 (2,069 ) 370 Corporate debt securities 4,015 (19 ) 1 1,948 (40 ) 1 5,963 (59 ) 2 Total temporarily impaired securities $ 664,477 $ (7,159 ) 312 $ 787,063 $ (19,501 ) 368 $ 1,451,540 $ (26,660 ) 680 Unrealized losses on debt securities in the tables represent temporary fluctuations resulting from changes in market rates in relation to fixed yields. Unrealized losses in the available-for-sale WesBanco does not believe the securities presented above are impaired due to reasons of credit quality, as substantially all debt securities are rated above investment grade and all are paying principal and interest according to their contractual terms. WesBanco does not intend to sell, nor is it more likely than not that it will be required to sell, loss position securities prior to recovery of their cost, and therefore, management believes the unrealized losses detailed above are temporary and no impairment loss relating to these securities has been recognized. Securities that do not have readily determinable fair values and for which WesBanco does not exercise significant influence are carried at cost. Cost method investments consist primarily of FHLB of Pittsburgh, Cincinnati and Indianapolis stock totaling $55.6 million and $45.9 million at March 31, 2018 and December 31, 2017, respectively, and are included in other assets in the Consolidated Balance Sheets. Cost method investments are evaluated for impairment whenever events or circumstances suggest that their carrying value may not be recoverable.

Loans and the Allowance for Cre

Loans and the Allowance for Credit Losses	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Loans and the Allowance for Credit Losses	NOTE 4. LOANS AND THE ALLOWANCE FOR CREDIT LOSSES The recorded investment in loans is presented in the Consolidated Balance Sheets net of deferred loan fees and costs, and discounts on purchased loans. The net deferred loan costs were $1.9 million and $1.6 million at March 31, 2018 and December 31, 2017, respectively. The unamortized discount on purchased loans from acquisitions was $20.8 million, including $10.0 million related to YCB, and $21.9 million at March 31, 2018 and December 31, 2017, respectively. (unaudited, in thousands) March 31, 2018 December 31, 2017 Commercial real estate: Land and construction $ 440,896 $ 392,597 Improved property 2,574,330 2,601,851 Total commercial real estate 3,015,226 2,994,448 Commercial and industrial 1,118,333 1,125,327 Residential real estate 1,345,993 1,353,301 Home equity 523,425 529,196 Consumer 319,561 339,169 Total portfolio loans 6,322,538 6,341,441 Loans held for sale 12,962 20,320 Total loans $ 6,335,500 $ 6,361,761 The following tables summarize changes in the allowance for credit losses applicable to each category of the loan portfolio: Allowance for Credit Losses By Category For the Three Months Ended March 31, 2018 and 2017 Commercial Commercial Real Estate- Real Estate- Land and Improved Commercial Residential Home Deposit (unaudited, in thousands) Construction Property & Industrial Real Estate Equity Consumer Overdraft Total Balance at December 31, 2017: Allowance for loan losses $ 3,117 $ 21,166 $ 9,414 $ 3,206 $ 4,497 $ 3,063 $ 821 $ 45,284 Allowance for loan commitments 119 26 173 7 212 37 — 574 Total beginning allowance for credit losses 3,236 21,192 9,587 3,213 4,709 3,100 821 45,858 Provision for credit losses: Provision for loan losses 1,090 (895 ) 919 202 262 583 (48 ) 2,113 Provision for loan commitments 57 (5 ) 3 — (4 ) 4 — 55 Total provision for credit losses 1,147 (900 ) 922 202 258 587 (48 ) 2,168 Charge-offs — (279 ) (109 ) (287 ) (576 ) (1,125 ) (267 ) (2,643 ) Recoveries 117 287 270 131 120 546 109 1,580 Net charge-offs 117 8 161 (156 ) (456 ) (579 ) (158 ) (1,063 ) Balance at March 31, 2018: Allowance for loan losses 4,324 20,279 10,494 3,252 4,303 3,067 615 46,334 Allowance for loan commitments 176 21 176 7 208 41 — 629 Total ending allowance for credit losses $ 4,500 $ 20,300 $ 10,670 $ 3,259 $ 4,511 $ 3,108 $ 615 $ 46,963 Balance at December 31, 2016: Allowance for loan losses $ 4,348 $ 18,628 $ 8,412 $ 4,106 $ 3,422 $ 3,998 $ 760 $ 43,674 Allowance for loan commitments 151 17 188 9 162 44 — 571 Total beginning allowance for credit losses 4,499 18,645 8,600 4,115 3,584 4,042 760 44,245 Provision for credit losses: Provision for loan losses (425 ) 983 832 330 365 583 66 2,734 Provision for loan commitments (8 ) — (31 ) 1 17 (2 ) — (23 ) Total provision for credit losses (433 ) 983 801 331 382 581 66 2,711 Charge-offs — (602 ) (880 ) (404 ) (108 ) (1,287 ) (338 ) (3,619 ) Recoveries 52 251 376 78 48 369 98 1,272 Net charge-offs 52 (351 ) (504 ) (326 ) (60 ) (918 ) (240 ) (2,347 ) Balance at March 31, 2017: Allowance for loan losses 3,975 19,260 8,740 4,110 3,727 3,663 586 44,061 Allowance for loan commitments 143 17 157 10 179 42 — 548 Total ending allowance for credit losses $ 4,118 $ 19,277 $ 8,897 $ 4,120 $ 3,906 $ 3,705 $ 586 $ 44,609 The following tables present the allowance for credit losses and recorded investments in loans by category: Allowance for Credit Losses and Recorded Investment in Loans Commercial Commercial Real Estate- Real Estate- Commercial Residential Deposit Land and Improved and Real Home Over- (unaudited, in thousands) Construction Property Industrial Estate Equity Consumer draft Total March 31, 2018 Allowance for credit losses: Allowance for loans individually evaluated for impairment $ — $ 387 $ — $ — $ — $ — $ — $ 387 Allowance for loans collectively evaluated for impairment 4,324 19,892 10,494 3,252 4,303 3,067 615 45,947 Allowance for loan commitments 176 21 176 7 208 41 — 629 Total allowance for credit losses $ 4,500 $ 20,300 $ 10,670 $ 3,259 $ 4,511 $ 3,108 $ 615 $ 46,963 Portfolio loans: Individually evaluated for impairment (1) $ — $ 2,104 $ — $ — $ — $ — $ — $ 2,104 Collectively evaluated for impairment 439,480 2,567,367 1,117,607 1,345,290 523,425 319,561 — 6,312,730 Acquired with deteriorated credit quality 1,416 4,859 726 703 — — — 7,704 Total portfolio loans $ 440,896 $ 2,574,330 $ 1,118,333 $ 1,345,993 $ 523,425 $ 319,561 $ — $ 6,322,538 December 31, 2017 Allowance for credit losses: Allowance for loans individually evaluated for impairment $ — $ 388 $ — $ — $ — $ — $ — $ 388 Allowance for loans collectively evaluated for impairment 3,117 20,778 9,414 3,206 4,497 3,063 821 44,896 Allowance for loan commitments 119 26 173 7 212 37 — 574 Total allowance for credit losses $ 3,236 $ 21,192 $ 9,587 $ 3,213 $ 4,709 $ 3,100 $ 821 $ 45,858 Portfolio loans: Individually evaluated for impairment (1) $ — $ 3,344 $ — $ — $ — $ — $ — $ 3,344 Collectively evaluated for impairment 391,140 2,593,393 1,124,544 1,352,587 529,196 339,163 — 6,330,023 Acquired with deteriorated credit quality 1,457 5,114 783 714 — 6 — 8,074 Total portfolio loans $ 392,597 $ 2,601,851 $ 1,125,327 $ 1,353,301 $ 529,196 $ 339,169 $ — $ 6,341,441 (1) Commercial loans greater than $1 million that are reported as non-accrual WesBanco maintains an internal loan grading system to reflect the credit quality of commercial loans. Commercial loan risk grades are determined based on an evaluation of the relevant characteristics of each loan, assigned at the inception of each loan and adjusted thereafter at any time to reflect changes in the risk profile throughout the life of each loan. The primary factors used to determine the risk grade are the reliability and sustainability of the primary source of repayment and overall financial strength of the borrower. This includes an analysis of cash flow available to repay debt, profitability, liquidity, leverage, and overall financial trends. Other factors include management, industry or property type risks, an assessment of secondary sources of repayment such as collateral or guarantees, other terms and conditions of the loan that may increase or reduce its risk, and economic conditions and other external factors that may influence repayment capacity and financial condition. Commercial real estate – land and construction consists of loans to finance investments in vacant land, land development, construction of residential housing, and construction of commercial buildings. Commercial real estate – improved property consists of loans for the purchase or refinance of all types of improved owner-occupied and investment properties. Factors that are considered in assigning the risk grade vary depending on the type of property financed. The risk grade assigned to construction and development loans is based on the overall viability of the project, the experience and financial capacity of the developer or builder to successfully complete the project, project specific and market absorption rates and comparable property values, and the amount of pre-sales pre-leases Commercial and industrial loans consist of revolving lines of credit to finance accounts receivable, inventory and other general business purposes; term loans to finance fixed assets other than real estate, and letters of credit to support trade, insurance or governmental requirements for a variety of businesses. Most C&I borrowers are privately-held companies with annual sales up to $100 million. Factors that are considered for commercial and industrial loans include the type, quality and marketability of non-real Pass loans are those that exhibit a history of positive financial results that are at least comparable to the average for their industry or type of real estate. The primary source of repayment is acceptable and these loans are expected to perform satisfactorily during most economic cycles. Pass loans typically have no significant external factors that are expected to adversely affect these borrowers more than others in the same industry or property type. Any minor unfavorable characteristics of these loans are outweighed or mitigated by other positive factors including but not limited to adequate secondary or tertiary sources of repayment. Criticized or compromised loans are currently protected but have weaknesses, which, if not corrected, may be inadequately protected at some future date. These loans represent an unwarranted credit risk and would generally not be extended in the normal course of lending. Specific issues which may warrant this grade include declining financial results, increased reliance on secondary sources of repayment or guarantor support and adverse external influences that may negatively impact the business or property. Substandard and doubtful loans are equivalent to the classifications used by banking regulators. Substandard loans are inadequately protected by the current repayment capacity and equity of the borrower or collateral pledged, if any. Substandard loans have one or more well-defined weaknesses that jeopardize their repayment or collection in full. These loans may or may not be reported as non-accrual. The following tables summarize commercial loans by their assigned risk grade: Commerical Loans by Internally Assigned Risk Grade (unaudited, in thousands) Commercial Commercial Commercial Total As of March 31, 2018 Pass $ 434,665 $ 2,526,334 $ 1,104,209 $ 4,065,208 Criticized - compromised 3,384 24,807 5,594 33,785 Classified - substandard 2,847 23,189 8,530 34,566 Classified - doubtful — — — — Total $ 440,896 $ 2,574,330 $ 1,118,333 $ 4,133,559 As of December 31, 2017 Pass $ 386,753 $ 2,548,805 $ 1,110,267 $ 4,045,825 Criticized - compromised 2,984 25,673 7,435 36,092 Classified - substandard 2,860 27,373 7,625 37,858 Classified - doubtful — — — — Total $ 392,597 $ 2,601,851 $ 1,125,327 $ 4,119,775 Residential real estate, home equity and consumer loans are not assigned internal risk grades other than as required by regulatory guidelines that are based primarily on the age of past due loans. WesBanco primarily evaluates the credit quality of residential real estate, home equity and consumer loans based on repayment performance and historical loss rates. The aggregate amount of residential real estate, home equity and consumer loans classified as substandard in accordance with regulatory guidelines was $19.4 million at March 31, 2018 and $22.8 million at December 31, 2017, of which $1.0 and $2.5 million were accruing, for each period, respectively. The aggregate amount of residential real estate, home equity and consumer loans classified as substandard are not included in the tables above. Acquired YCB Loans 310-30 non-accrual. Acquired ESB Loans 310-30 non-accrual. The following table provides changes in accretable yield for loans acquired with deteriorated credit quality: For the Three Months Ended (unaudited, in thousands) March 31, March 31, Balance at beginning of period $ 1,724 $ 1,717 Acquisitions — — Reduction due to change in projected cash flows (86 ) (200 ) Reclass from non-accretable difference 2,841 174 Transfers out — — Accretion (268 ) (151 ) Balance at end of period $ 4,211 $ 1,540 The following tables summarize the age analysis of all categories of loans: Age Analysis of Loans (unaudited, in thousands) Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due Total Past Due Total Loans 90 Days or More Past Due and Accruing (1) As of March 31, 2018 Commercial real estate: Land and construction $ 439,926 $ — $ — $ 970 $ 970 $ 440,896 $ 172 Improved property 2,559,491 4,431 528 9,880 14,839 2,574,330 364 Total commercial real estate 2,999,417 4,431 528 10,850 15,809 3,015,226 536 Commercial and industrial 1,115,453 667 201 2,012 2,880 1,118,333 21 Residential real estate 1,333,175 3,860 1,618 7,340 12,818 1,345,993 561 Home equity 517,172 2,654 682 2,917 6,253 523,425 251 Consumer 316,517 1,950 432 662 3,044 319,561 210 Total portfolio loans 6,281,734 13,562 3,461 23,781 40,804 6,322,538 1,579 Loans held for sale 12,962 — — — — 12,962 — Total loans $ 6,294,696 $ 13,562 $ 3,461 $ 23,781 $ 40,804 $ 6,335,500 $ 1,579 Impaired loans included above are as follows: Non-accrual $ 8,120 $ 1,310 $ 754 $ 22,202 $ 24,266 $ 32,386 TDRs accruing interest (1) 6,435 230 193 — 423 6,858 Total impaired $ 14,555 $ 1,540 $ 947 $ 22,202 $ 24,689 $ 39,244 As of December 31, 2017 Commercial real estate: Land and construction $ 392,189 $ — $ 172 $ 236 $ 408 $ 392,597 $ — Improved property 2,589,704 374 1,200 10,573 12,147 2,601,851 243 Total commercial real estate 2,981,893 374 1,372 10,809 12,555 2,994,448 243 Commercial and industrial 1,121,957 572 196 2,602 3,370 1,125,327 20 Residential real estate 1,338,240 4,487 2,376 8,198 15,061 1,353,301 1,113 Home equity 522,584 2,135 683 3,794 6,612 529,196 742 Consumer 334,723 2,466 842 1,138 4,446 339,169 608 Total portfolio loans 6,299,397 10,034 5,469 26,541 42,044 6,341,441 2,726 Loans held for sale 20,320 — — — — 20,320 — Total loans $ 6,319,717 $ 10,034 $ 5,469 $ 26,541 $ 42,044 $ 6,361,761 $ 2,726 Impaired loans included above are as follows: Non-accrual $ 9,195 $ 1,782 $ 2,033 $ 23,815 $ 27,630 $ 36,825 TDRs accruing interest (1) 6,055 348 168 — 516 6,571 Total impaired $ 15,250 $ 2,130 $ 2,201 $ 23,815 $ 28,146 $ 43,396 (1) Loans 90 days or more past due and accruing interest exclude TDRs 90 days or more past due and accruing interest. The following tables summarize impaired loans: Impaired Loans March 31, 2018 December 31, 2017 Unpaid Principal Balance (1) Recorded Investment Related Allowance Unpaid Principal Balance (1) Recorded Investment Related Allowance (unaudited, in thousands) With no related specific allowance recorded: Commercial real estate: Land and construction $ 873 $ 800 $ — $ 412 $ 239 $ — Improved property 14,554 10,319 — 18,229 12,863 — Commercial and industrial 3,045 2,496 — 3,745 3,086 — Residential real estate 19,601 17,751 — 20,821 18,982 — Home equity 5,771 4,971 — 5,833 5,169 — Consumer 918 803 — 1,084 952 — Total impaired loans without a specific allowance 44,762 37,140 — 50,124 41,291 — With a specific allowance recorded: Commercial real estate: Land and construction — — — — — — Improved property 2,104 2,104 387 2,105 2,105 388 Commercial and industrial — — — — — — Total impaired loans with a specific allowance 2,104 2,104 387 2,105 2,105 388 Total impaired loans $ 46,866 $ 39,244 $ 387 $ 52,229 $ 43,396 $ 388 (1) The difference between the unpaid principal balance and the recorded investment generally reflects amounts that have been previously charged-off Impaired Loans For the Three Months Ended March 31, 2018 For the Three Months Ended March 31, 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (unaudited, in thousands) With no related specific allowance recorded: Commercial real estate: Land and construction $ 520 $ — $ 588 $ — Improved property 11,591 345 9,620 346 Commercial and industrial 2,791 2 3,812 2 Residential real estate 18,367 66 18,448 69 Home equity 5,070 5 4,186 5 Consumer 878 3 761 2 Total impaired loans without a specific allowance 39,217 421 37,415 424 With a specific allowance recorded: Commercial real estate: Land and construction — — — — Improved property 2,105 — 4,927 — Commercial and industrial — — 635 — Total impaired loans with a specific allowance 2,105 — 5,562 — Total impaired loans $ 41,322 $ 421 $ 42,977 $ 424 The following tables present the recorded investment in non-accrual Non-accrual (unaudited, in thousands) March 31, December 31, 2017 Commercial real estate: Land and construction $ 800 $ 239 Improved property 10,821 13,318 Total commercial real estate 11,621 13,557 Commercial and industrial 2,373 2,958 Residential real estate 13,149 14,661 Home equity 4,540 4,762 Consumer 703 887 Total $ 32,386 $ 36,825 (1) At March 31, 2018, there were 2 borrowers with loans greater than $1.0 million totaling $5.6 million, as compared to three borrowers with loans greater than $1.0 million totaling $6.8 million at December 31, 2017. Total non-accrual non-accrual TDRs March 31, 2018 December 31, 2017 (unaudited, in thousands) Accruing Non-Accrual Total Accruing Non-Accrual Total Commercial real estate: Land and construction $ — $ 2 $ 2 $ — $ 3 $ 3 Improved property 1,602 490 2,092 1,650 428 2,078 Total commercial real estate 1,602 492 2,094 1,650 431 2,081 Commercial and industrial 123 94 217 128 97 225 Residential real estate 4,602 1,525 6,127 4,321 1,880 6,201 Home equity 431 220 651 407 337 744 Consumer 100 66 166 65 120 185 Total $ 6,858 $ 2,397 $ 9,255 $ 6,571 $ 2,865 $ 9,436 As of March 31, 2018 and December 31, 2017 there were no TDRs greater than $1.0 million. The concessions granted in the majority of loans reported as accruing and non-accrual The following tables present details related to loans identified as TDRs during the three months ended March 31, 2018 and 2017, respectively: New TDRs (1) For the Three Months Ended March 31, 2018 March 31, 2017 Pre- Post- Pre- Post- Modification Modification Modification Modification Outstanding Outstanding Outstanding Outstanding Number of Recorded Recorded Number of Recorded Recorded (unaudited, dollars in thousands) Modifications Investment Investment Modifications Investment Investment Commercial real estate: Land and construction — $ — $ — — $ — $ — Improved Property — — — — — — Total commercial real estate — — — — — — Commercial and industrial — — — 2 126 122 Residential real estate 5 203 195 1 10 9 Home equity — — — 1 44 43 Consumer 2 4 3 2 84 21 Total 7 $ 207 $ 198 6 $ 264 $ 195 (1) Excludes loans that were either paid off or charged-off pre-modification The following table summarizes TDRs which defaulted (defined as past due 90 days) during the three months ended March 31, 2018 and 2017, respectively, that were restructured within the last twelve months prior to March 31, 2018 and 2017, respectively: Defaulted TDRs (1) Defaulted TDRs (1) For the Three Months Ended For the Three Months Ended March 31, 2018 March 31, 2017 (unaudited, dollars in thousands) Number of Recorded Investment Number of Defaults Recorded Investment Commercial real estate: Land and construction — $ — — $ — Improved property — — — — Total commercial real estate — — — — Commercial and industrial — — — — Residential real estate 1 122 — — Home equity 1 7 — — Consumer — — 1 9 Total 2 $ 129 1 $ 9 (1) Excludes loans that were either charged-off TDRs that default are placed on non-accrual The following table summarizes other real estate owned and repossessed assets included in other assets: (unaudited, in thousands) March 31, December 31, Other real estate owned $ 3,991 $ 5,195 Repossessed assets 76 102 Total other real estate owned and repossessed assets $ 4,067 $ 5,297 Residential real estate included in other real estate owned at March 31, 2018 and December 31, 2017 was $0.9 million and $1.5 million, respectively. At March 31, 2018 and December 31, 2017, formal foreclosure proceedings were in process on residential real estate loans totaling $4.3 million and $3.5 million, respectively.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	NOTE 5. DERIVATIVES AND HEDGING ACTIVITIES Risk Management Objective of Using Derivatives WesBanco is exposed to certain risks arising from both its business operations and economic conditions. WesBanco principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. WesBanco manages economic risks, including interest rate, liquidity, and credit risk, primarily by managing the amount, sources, and duration of its assets and liabilities. WesBanco’s existing interest rate derivatives result from a service provided to certain qualifying customers and, therefore, are not used to manage interest rate risk in WesBanco’s assets or liabilities. WesBanco manages a matched book with respect to its derivative instruments in order to minimize its net risk exposure resulting from such transactions. A matched book is when the Bank’s assets and liabilities are equally distributed but also have similar maturities. Loan Swaps WesBanco executes interest rate swaps with commercial banking customers to facilitate their respective risk management strategies. Those interest rate swaps are simultaneously hedged by offsetting interest rate swaps that WesBanco executes with a third party, such that WesBanco minimizes its net risk exposure resulting from such transactions. As the interest rate swaps associated with this program do not meet the strict hedge accounting requirements of FASB ASC 815, changes in the fair value of both the customer swaps and the offsetting third-party swaps are recognized directly in earnings. As of March 31, 2018 and December 31, 2017, WesBanco had 43 and 39, respectively, interest rate swaps with an aggregate notional amount of $309.2 million and $298.2 million, respectively, related to this program. During the three months ended March 31, 2018 and 2017, WesBanco recognized net gains (net losses) of $0.2 million and $(0.2) million, respectively, related to the changes in fair value of these swaps. Additionally, WesBanco recognized $0.4 million and $1.0 million of income for the related swap fees for the three months ended March 31, 2018 and 2017, respectively. Mortgage Loans Held for Sale and Loan Commitments Certain residential mortgage loans are originated for sale in the secondary mortgage loan market. These loans are classified as held for sale and carried at fair value as WesBanco has elected the fair value option. Fair value is determined based on rates obtained from the secondary market for loans with similar characteristics. WesBanco sells loans to the secondary market on a mandatory or best efforts basis. The loans sold on a mandatory basis are not committed to an investor until the loan is closed with the borrower. WesBanco enters into forward TBA contracts to manage the interest rate risk between the loan commitment and the closing of the loan. The loans sold on a best efforts basis are committed to an investor simultaneous to the interest rate commitment with the borrower. Fair Values of Derivative Instruments on the Balance Sheet All derivatives are carried on the consolidated balance sheet at fair value. Derivative assets are classified in the consolidated balance sheet under other assets, and derivative liabilities are classified in the consolidated balance sheet under other liabilities. Changes in fair value are recognized in earnings. None of WesBanco’s derivatives are designated in qualifying hedging relationships under ASC 815. The table below presents the fair value of WesBanco’s derivative financial instruments as well as their classification on the Balance Sheet as of March 31, 2018 and December 31, 2017: March 31, 2018 December 31, 2017 (unaudited, in thousands) Notional or Contractual Asset Derivatives Liability Derivatives Notional or Contractual Amount Asset Derivatives Liability Derivatives Derivatives Loan Swaps: Interest rate swaps $ 309,242 $ 9,257 $ 9,083 $ 298,223 $ 7,351 $ 7,345 Other contracts: Interest rate loan commitments 24,730 147 — 20,319 49 — Best efforts forward delivery commitments 3,941 — 11 2,905 — 6 Forward TBA contracts 36,500 — 3 31,750 — 23 Total derivatives $ 9,404 $ 9,097 $ 7,400 $ 7,374 Effect of Derivative Instruments on the Income Statement The table below presents the change in the fair value of the Company’s derivative financial instruments reflected within the other non-interest For the Three Months Ended Location of Gain/(Loss) March 31, (unaudited, in thousands) 2018 2017 Interest rate swaps Other income $ (167 ) $ 195 Interest rate loan commitments Mortgage banking income 98 — Best efforts forward sales contracts Mortgage banking income (5 ) — Forward TBA contracts Mortgage banking income 410 — Total $ 336 $ 195 Credit-risk-related Contingent Features WesBanco has agreements with its derivative counterparties that contain a provision where if WesBanco defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then WesBanco could also be declared in default on its derivative obligations. WesBanco also has agreements with certain of its derivative counterparties that contain a provision where if WesBanco fails to maintain its status as either a well or adequately capitalized institution, then the counterparty could terminate the derivative positions and WesBanco would be required to settle its obligations under the agreements. WesBanco has minimum collateral posting thresholds with certain of its derivative counterparties and has posted collateral with a market value of $2.9 million as of March 31, 2018. If WesBanco had breached any of these provisions at March 31, 2018, it could have been required to settle its obligations under the agreements at the termination value and would have been required to pay any additional amounts due in excess of amounts previously posted as collateral with the respective counterparty.

Pension Plan

Pension Plan	3 Months Ended
	Mar. 31, 2018
Retirement Benefits [Abstract]
Pension Plan	NOTE 6. PENSION PLAN The following table presents the net periodic pension cost for WesBanco’s Defined Benefit Pension Plan (the “Plan”) and the related components: For the Three Months Ended March 31, (unaudited, in thousands) 2018 2017 Service cost – benefits earned during year $ 699 $ 636 Interest cost on projected benefit obligation 1,114 1,084 Expected return on plan assets (2,204 ) (1,886 ) Amortization of prior service cost 6 6 Amortization of net loss 753 794 Net periodic pension cost $ 368 $ 634 The Plan covers all employees of WesBanco and its subsidiaries who were hired on or before August 1, 2007 who satisfy minimum age and length of service requirements, and is not available to employees hired after such date. A minimum required contribution of $5.1 million is due for 2018, which could be all or partially offset by the Plan’s $56.9 million available credit balance. WesBanco currently expects to make a voluntary contribution of $5.0 million to the Plan in 2018. WesBanco assumed YCB’s obligation for a predecessor bank’s participation in the Pentegra Defined Benefit Plan for Financial Institutions (“Pentegra Plan”). The participating employer plan has been frozen to new participants since 2002. WesBanco spun off the assets from the Pentegra Plan, contributing approximately $2.8 million to satisfy the estimated final costs to do so. This spin off had no impact on earnings as the liability was included in YCB’s balance sheet as of the acquisition date. The distributed assets from the Pentegra Plan were transferred to a plan providing substantially the same benefits to the participants. The net periodic pension income for this plan for the three months ended March 31, 2018 was $62 thousand, which was comprised of a $0.2 million expected return on plan assets and a $3 thousand recognized net actuarial gain partially offset by a $0.1 million interest cost on projected benefit obligation. No minimum contribution is due for this plan for fiscal year 2018; however, WesBanco expects to make a voluntary contribution of $0.2 million.

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement	NOTE 7. FAIR VALUE MEASUREMENT Fair value estimates are based on quoted market prices, if available, quoted market prices of similar assets or liabilities, or the present value of expected future cash flows and other valuation techniques. These valuations are significantly affected by discount rates, cash flow assumptions, and risk assumptions used. Therefore, fair value estimates may not be substantiated by comparison to independent markets and are not intended to reflect the proceeds that may be realizable in an immediate settlement of the instruments. Fair value is determined at one point in time and is not representative of future value. These amounts do not reflect the total value of a going concern organization. Management does not have the intention to dispose of a significant portion of its assets and liabilities, and therefore the unrealized gains or losses should not be interpreted as a forecast of future earnings and cash flows. The following is a discussion of assets and liabilities measured at fair value on a recurring basis and valuation techniques applied: Investment securities: Derivatives: WesBanco enters into forward TBA contracts to manage the interest rate risk between the loan commitments to the customer and the closing of the loan for loans that will be sold on a mandatory basis to secondary market investors. The forward TBA contract is reported at fair value in other assets and other liabilities on the consolidated balance sheet with any resulting gain or loss recorded in current period’s earnings as mortgage banking income. WesBanco determines the fair value for derivatives using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects contractual terms of the derivative, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. WesBanco incorporates credit valuation adjustments to appropriately reflect both its own non-performance non-performance We may be required from time to time to measure certain assets and liabilities at fair value on a nonrecurring basis in accordance with GAAP. These adjustments to fair value usually result from the application of lower of cost or market accounting or write-downs of individual assets and liabilities. Impaired loans: Other real estate owned and repossessed assets: Loans held for sale: Certain investments that are measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been categorized in the fair value hierarchy. The fair value amounts presented in the table below are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statement of financial position. The following tables set forth WesBanco’s financial assets and liabilities that were accounted for at fair value on a recurring and nonrecurring basis by level within the fair value hierarchy as of March 31, 2018 and December 31, 2017: March 31, 2018 Fair Value Measurements Using: March 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Investments Measured at Net Asset (unaudited, in thousands) (level 1) (level 2) (level 3) Value Recurring fair value measurements Equity securities $ 13,986 $ 11,568 $ — $ — $ 2,418 Debt securities - available-for-sale U.S. Treasury 9,894 — 9,894 — — U.S. Government sponsored entities and agencies 96,458 — 96,458 — — Residential mortgage-backed securities and collateralized mortgage obligations of government agencies 1,344,410 — 1,344,410 — — Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 140,926 — 140,926 — — Obligations of state and political subdivisions 101,431 — 101,431 — — Corporate debt securities 35,258 — 35,258 — — Total debt securities - available-for-sale $ 1,728,377 $ — $ 1,728,377 $ — $ — Loans held for sale 12,962 — 12,962 — — Other assets - interest rate derivatives agreements 9,257 — 9,257 — — Total assets recurring fair value measurements $ 1,764,582 $ 11,568 $ 1,750,596 $ — $ 2,418 Other liabilities - interest rate derivatives agreements $ 9,083 $ — $ 9,083 $ — $ — Total liabilities recurring fair value measurements $ 9,083 $ — $ 9,083 $ — $ — Nonrecurring fair value measurements Impaired loans $ 1,717 $ — $ — $ 1,717 $ — Other real estate owned and repossessed assets 4,067 — — 4,067 — Total nonrecurring fair value measurements $ 5,784 $ — $ — $ 5,784 $ — December 31, 2017 Fair Value Measurements Using: December 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Investments Measured at Net Asset (unaudited, in thousands) 2017 (level 1) (level 2) (level 3) Value Recurring fair value measurements Equity securities $ 13,457 $ 11,391 $ — $ — $ 2,066 Debt securities - available-for-sale U.S. Government sponsored entities and agencies 71,843 — 71,843 — — Residential mortgage-backed securities and collateralized mortgage obligations of government agencies 934,922 — 934,922 — — Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 114,867 — 114,867 — — Obligations of state and political subdivisions 104,830 — 104,830 — — Corporate debt securities 35,403 — 35,403 — — Total debt securities - available-for-sale $ 1,261,865 $ — $ 1,261,865 $ — $ — Loans held for sale 20,320 — 20,320 — — Other assets - interest rate derivatives agreements 7,351 — 7,351 — — Total assets recurring fair value measurements $ 1,302,993 $ 11,391 $ 1,289,536 $ — $ 2,066 Other liabilities - interest rate derivatives agreements $ 7,345 $ — $ 7,345 $ — $ — Total liabilities recurring fair value measurements $ 7,345 $ — $ 7,345 $ — $ — Nonrecurring fair value measurements Impaired loans $ 1,717 $ — $ — $ 1,717 $ — Other real estate owned and repossessed assets 5,297 — — 5,297 — Total nonrecurring fair value measurements $ 7,014 $ — $ — $ 7,014 $ — WesBanco’s policy is to recognize transfers between levels as of the actual date of the event or change in circumstances that caused the transfer. There were no significant transfers between level 1, 2 or 3 for the three months ended March 31, 2018 or for the year ended December 31, 2017. The following table presents additional quantitative information about assets measured at fair value on a nonrecurring basis and for which WesBanco has utilized level 3 inputs to determine fair value: Quantitative Information about Level 3 Fair Value Measurements Fair Value Valuation Unobservable Range (Weighted (unaudited, in thousands) Estimate Techniques Input Average) March 31, 2018 Impaired loans $ 1,717 Appraisal of collateral (1) Appraisal adjustments (2) (4.8%) / (4.8%) Liquidation expenses (2) (7.6%) / (7.6%) Other real estate owned and repossessed assets 4,067 Appraisal of collateral (1), (3) December 31, 2017: Impaired loans $ 1,717 Appraisal of collateral (1) Appraisal adjustments (2) (4.8%) / (4.8%) Liquidation expenses (2) (7.6%) / (7.6%) Other real estate owned and repossessed assets 5,297 Appraisal of collateral (1), (3) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of appraisal adjustments and liquidation expenses are presented as a percent of the appraisal. (3) Includes estimated liquidation expenses and numerous dissimilar qualitative adjustments by management which are not identifiable. The estimated fair values of WesBanco’s financial instruments are summarized below: Fair Value Measurements at March 31, 2018 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Active Markets for Identical Assets (level 1) Significant Other Observable Inputs (level 2) Significant Unobservable Inputs (level 3) Investments Measured at Net Asset Value Financial Assets Cash and due from banks $ 100,845 $ 100,845 $ 100,845 $ — $ — $ — Equity securities 13,986 13,986 11,568 — — 2,418 Debt securities available-for-sale 1,728,377 1,728,377 — 1,728,377 — — Debt securities held-to-maturity 1,006,042 1,005,502 — 1,004,912 590 — Net loans 6,276,204 6,158,399 — — 6,158,399 — Loans held for sale 12,962 12,962 — 12,962 — — Other assets - interest rate derivatives 9,257 9,257 — 9,257 — — Accrued interest receivable 31,963 31,963 31,963 — — — Financial Liabilities Deposits 7,226,326 7,230,335 6,018,657 1,211,678 — — Federal Home Loan Bank borrowings 1,166,939 1,161,442 — 1,161,442 — — Other borrowings 207,653 207,627 205,651 1,976 — — Subordinated debt and junior subordinated debt 164,379 149,887 — 149,887 — — Other liabilities - interest rate derivatives 9,083 9,083 — 9,083 — — Accrued interest payable 4,033 4,033 4,033 — — — Fair Value Measurements at December 31, 2017 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Active Markets for Identical Assets (level 1) Significant Other Observable Inputs (level 2) Significant Unobservable Inputs (level 3) Investments Measured at Net Asset Value Financial Assets Cash and due from banks $ 117,572 $ 117,572 $ 117,572 $ — $ — $ — Equity securities 13,457 13,457 11,391 — — 2,066 Debt securities available-for-sale 1,261,865 1,261,865 — 1,261,865 — — Debt securities held-to-maturity 1,009,500 1,023,784 — 1,023,191 593 — Net loans 6,296,157 6,212,823 — — 6,212,823 — Loans held for sale 20,320 20,320 — 20,320 — — Other assets - interest rate derivatives 7,351 7,351 — 7,351 — — Accrued interest receivable 29,728 29,728 29,728 — — — Financial Liabilities Deposits 7,043,588 7,053,536 5,766,531 1,287,005 — — Federal Home Loan Bank borrowings 948,203 944,706 — 944,706 — — Other borrowings 184,805 184,814 182,785 2,029 — — Subordinated debt and junior subordinated debt 164,327 146,484 — 146,484 — — Other liabilities - interest rate derivatives 7,345 7,345 — 7,345 — — Accrued interest payable 3,178 3,178 3,178 — — — The following methods and assumptions were used to measure the fair value of financial instruments recorded at cost on WesBanco’s consolidated balance sheets: Cash and due from banks: Debt securities held-to-maturity: held-to-maturity Net loans: Accrued interest receivable: . Deposits: Federal Home Loan Bank borrowings: Other borrowings: Subordinated debt and junior subordinated debt: Accrued interest payable: Off-balance Off-balance

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2018
Text Block [Abstract]
Revenue Recognition	NOTE 8. REVENUE RECOGNITION WesBanco adopted ASU 2014-09 Revenue from Contracts with Customers Trust fees: Service charges on deposits: Electronic banking fees: Net securities brokerage revenue: Mortgage banking income: Net gain or loss on sale of other real estate owned: The following table summarizes the point of revenue recognition and the income recognized for each of the revenue streams for the three months ended March 31, 2018: (unaudited, in thousands) Point of Revenue Recognition For the Three Months Ended March 31, 2018 Revenue Streams Trust Fees Trust account fees Over time $ 4,292 WesMark fees Over time 2,211 Total trust fees 6,503 Service charges on deposits Commercial banking fees Over time 407 Personal service charges At a point in time & Over time 4,415 Total service charges on deposits 4,822 Net securities brokerage revenue Annuity commissions At a point in time 1,200 Equity and debt security trades At a point in time 102 Managed money Over time 141 Trail commissions Over time 227 Total net securities brokerage revenue 1,670 Electronic banking fees At a point in time 4,829 Mortgage banking income At a point in time 1,004 Gain/loss on sale of OREO/other assets At a point in time 262

Comprehensive Income_(Loss)

Comprehensive Income/(Loss)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Comprehensive Income/(Loss)	NOTE 9. COMPREHENSIVE INCOME/(LOSS) The activity in accumulated other comprehensive income for the three months ended March 31, 2018 and 2017 is as follows: Accumulated Other Comprehensive Income/(Loss) (1) (unaudited, in thousands) Defined Unrealized Gains (Losses) on Debt Securities Available-for-Sale Unrealized Gains on Debt Securities Transferred from Available-for-Sale to Held-to-Maturity Total Balance at December 31, 2017 $ (18,626 ) $ (13,250 ) $ 381 $ (31,495 ) Other comprehensive income before reclassifications — (14,905 ) — (14,905 ) Amounts reclassified from accumulated other comprehensive income 437 — (50 ) 387 Period change 437 (14,905 ) (50 ) (14,518 ) Adoption of Accounting Standard ASU 2016-01 — (1,063 ) — (1,063 ) Balance at March 31, 2018 $ (18,189 ) $ (29,218 ) $ 331 $ (47,076 ) Balance at December 31, 2016 $ (17,758 ) $ (9,890 ) $ 522 $ (27,126 ) Other comprehensive income before reclassifications — 1,680 — 1,680 Amounts reclassified from accumulated other comprehensive income 655 — (50 ) 605 Period change 655 1,680 (50 ) 2,285 Balance at March 31, 2017 $ (17,103 ) $ (8,210 ) $ 472 $ (24,841 ) (1) All amounts are net of tax. Related income tax expense or benefit is calculated using a combined Federal and State income tax rate approximating 23% in 2018 and 37% in all prior periods. (2) See Note 1, Summary of Significant Accounting Policies for additional information about WesBanco’s adoption of ASU 2016-01. The following table provides details about amounts reclassified from accumulated other comprehensive income for the three months ended March 31, 2018 and 2017: Details about Accumulated Other Comprehensive Income/(Loss) Components Amounts Reclassified from Accumulated Other Comprehensive Income/(Loss) For the Three Months Ended March 31, Affected Line Item in the Statement of Net Income (unaudited, in thousands) 2018 2017 Debt securities available-for-sale (1) Net securities gains reclassified into earnings $ — $ — Net securities gains (Non-interest Related income tax expense — — Provision for income taxes Net effect on accumulated other comprehensive income for the period — — Debt securities held-to-maturity (1) Amortization of unrealized gain transferred from available-for-sale (66 ) (72 ) Interest and dividends on securities (Interest and dividend income) Related income tax expense 16 22 Provision for income taxes Net effect on accumulated other comprehensive income for the period (50 ) (50 ) Defined benefit pension plan (2) Amortization of net loss and prior service costs 756 801 Employee benefits (Non-interest Related income tax benefit (319 ) (146 ) Provision for income taxes Net effect on accumulated other comprehensive income for the period 437 655 Total reclassifications for the period $ 387 $ 605 (1) For additional detail related to unrealized gains on securities and related amounts reclassified from accumulated other comprehensive income, see Note 3, “Securities.” (2) Included in the computation of net periodic pension cost. See Note 6, “Pension Plan” for additional detail.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	NOTE 10. COMMITMENTS AND CONTINGENT LIABILITIES Commitments — off-balance non-performance Letters of credit are conditional commitments issued by banks to guarantee the performance of a customer to a third party. Those guarantees are primarily issued to support public and private borrowing arrangements, including normal business activities, bond financing and similar transactions. Letters of credit are considered guarantees. The liability associated with letters of credit was $0.2 million as of both March 31, 2018 and December 31, 2017. Contingent obligations and other guarantees include affordable housing plan guarantees, credit card guarantees and obligations under the FHLB’s loan purchasing program. Affordable housing plan guarantees are performance guarantees for various building project loans. The guarantee amortizes as the loan balances decrease. Credit card guarantees are credit card balances not owned by WesBanco, whereby the Bank guarantees the performance of the cardholder. The mortgages sold to FHLB obligate WesBanco to reimburse the FHLB for a portion of the loan balances that default. The following table presents total commitments to extend credit, guarantees and various letters of credit outstanding: March 31, December 31, (unaudited, in thousands) 2018 2017 Lines of credit $ 1,464,970 $ 1,452,697 Loans approved but not closed 358,367 245,644 Overdraft limits 124,752 126,671 Letters of credit 31,947 31,951 Contingent obligations and other guarantees 6,796 6,700 Contingent Liabilities —

Business Segments

Business Segments	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Business Segments	NOTE 11. BUSINESS SEGMENTS WesBanco operates two reportable segments: community banking and trust and investment services. WesBanco’s community banking segment offers services traditionally offered by full-service commercial banks, including commercial demand, individual demand and time deposit accounts, as well as commercial, mortgage and individual installment loans, and certain non-traditional Condensed financial information by business segment is presented below: Trust and Community Investment (unaudited, in thousands) Banking Services Consolidated For the Three Months ended March 31, 2018: Interest and dividend income $ 86,417 $ — $ 86,417 Interest expense 13,125 — 13,125 Net interest income 73,292 — 73,292 Provision for credit losses 2,168 — 2,168 Net interest income after provision for credit losses 71,124 — 71,124 Non-interest 17,477 6,503 23,980 Non-interest 50,894 3,677 54,571 Income before provision for income taxes 37,707 2,826 40,533 Provision for income taxes 6,411 593 7,004 Net income $ 31,296 $ 2,233 $ 33,529 For the Three Months ended March 31, 2017: Interest and dividend income $ 79,924 $ — $ 79,924 Interest expense 9,205 — 9,205 Net interest income 70,719 — 70,719 Provision for credit losses 2,711 — 2,711 Net interest income after provision for credit losses 68,008 — 68,008 Non-interest 16,741 6,143 22,884 Non-interest 50,992 3,392 54,384 Income before provision for income taxes 33,757 2,751 36,508 Provision for income taxes 9,522 1,100 10,622 Net income $ 24,235 $ 1,651 $ 25,886 Total non-fiduciary

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	NOTE 12. SUBSEQUENT EVENTS On April 5, 2018, WesBanco completed its acquisition of First Sentry Bancshares, Inc. (“FTSB”), a bank holding company headquartered in Huntington, West Virginia. As of March 31, 2018, FTSB had approximately $705.1 million in assets excluding goodwill, $577.4 million in total deposits, $459.5 million in total loans and 5 branches in West Virginia. The acquisition was valued at approximately $107.5 million and resulted in WesBanco issuing approximately 2.5 million shares of its common stock and $1.0 million in cash in exchange for FTSB common stock. The assets and liabilities of FTSB will be recorded on WesBanco’s balance sheet at their preliminary estimated fair values as of April 5, 2018, the acquisition date, and FTSB’s results of operations will be included in WesBanco’s Consolidated Statements of Income from that date. For the three months ended March 31, 2018, WesBanco recorded merger-related expenses of $0.2 million associated with the FTSB acquisition. WesBanco accounts for business combinations using the acquisition method of accounting. The initial accounting and determination of the fair values of the assets and liabilities resulting from the acquisition was incomplete at the time of this filing due to the timing of the closing of the acquisition in relation to WesBanco’s required Form 10-Q 10-Q On April 19, 2018, WesBanco and Farmers Capital Bank Corporation (“Farmers”), a bank holding company headquartered in Frankfort, Kentucky with approximately $1.7 billion in assets, $1.4 billion in deposits, $1.0 billion in loans and 34 branches, jointly announced that a definitive Agreement and Plan of Merger was executed providing for the merger of Farmers with and into WesBanco. On the date of the announcement, the transaction was valued at approximately $378.2 million. Under the terms of the Agreement and Plan of Merger, which has been approved by that board of directors of both companies, WesBanco will exchange a combination of its common stock and cash for Farmers common stock. Farmers shareholders will be entitled to receive 1.053 shares of WesBanco common stock and cash in the amount of $5.00 per share for each share of Farmers’common stock for a total value of approximately $50.31 per share at the date of announcement. The receipt by Farmers’ shareholders of shares of WesBanco common stock in exchange for their shares of Farmers common stock is anticipated to qualify as a tax-free

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation — 10-Q S-X. 10-K WesBanco’s interim financial statements have been prepared following the significant accounting policies disclosed in Note 1 of the Notes to the Consolidated Financial Statements of its 2017 Annual Report on Form 10-K
Recent accounting pronouncements	Recent accounting pronouncements — No. 2017-12, 2017-12 In March 2017, the FASB issued ASU 2017-07 non-interest In January 2017, the FASB issued ASU No. 2017-01, 2017-01 In October 2016, the FASB issued ASU 2016-16 In August 2016, the FASB issued ASU 2016-15 zero-coupon In June 2016, the FASB issued ASU 2016-13 held-to-maturity available-for-sale In February 2016, the FASB issued ASU 2016-02 2018-01, non-cancellable In January 2016, the FASB issued ASU 2016-01 2018-03, 2016-01. available-for-sale held-to-maturity In May 2014, the FASB issued ASU 2014-09 one-year 2016-08, 2016-10, 2016-12,

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Summary of Earnings Per Common Share	Earnings per common share are calculated as follows: For the Three Months Ended (unaudited, in thousands, except shares and per share amounts) 2018 2017 Numerator for both basic and diluted earnings per common share: Net income $ 33,529 $ 25,886 Denominator: Total average basic common shares outstanding 44,050,701 43,947,563 Effect of dilutive stock options and other stock compensation 117,541 73,202 Total diluted average common shares outstanding 44,168,242 44,020,765 Earnings per common share – basic $ 0.76 $ 0.59 Earnings per common share – diluted $ 0.76 $ 0.59

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of Fair Value and Amortized Cost of Available-for-sale and Held-to-maturity Debt Securities	The following table presents the fair value and amortized cost of available-for-sale held-to-maturity March 31, 2018 December 31, 2017 (unaudited, in thousands) Amortized Gross Gross Estimated Value Amortized Gross Gross Estimated Value Available-for-sale U.S. Treasury $ 9,900 $ — $ (6 ) $ 9,894 $ — $ — $ — $ — U.S. Government sponsored entities and agencies 98,166 1 (1,709 ) 96,458 72,425 24 (606 ) 71,843 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 1,377,904 214 (33,708 ) 1,344,410 954,115 214 (19,407 ) 934,922 Commerical mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 144,568 19 (3,661 ) 140,926 116,448 4 (1,585 ) 114,867 Obligations of states and political subdivisions 100,531 2,093 (1,193 ) 101,431 102,363 2,927 (460 ) 104,830 Corporate debt securities 35,219 170 (131 ) 35,258 35,234 228 (59 ) 35,403 Total available-for-sale $ 1,766,288 $ 2,497 $ (40,408 ) $ 1,728,377 $ 1,280,585 $ 3,397 $ (22,117 ) $ 1,261,865 Held-to-maturity U.S. Government sponsored entities and agencies $ 11,263 $ — $ (373 ) $ 10,890 $ 11,465 $ — $ (325 ) $ 11,140 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 162,904 301 (4,987 ) 158,218 170,025 544 (2,609 ) 167,960 Obligations of states and political subdivisions 798,536 10,510 (5,838 ) 803,208 794,655 17,364 (1,609 ) 810,410 Corporate debt securities 33,339 82 (235 ) 33,186 33,355 919 — 34,274 Total held-to-maturity $ 1,006,042 $ 10,893 $ (11,433 ) $ 1,005,502 $ 1,009,500 $ 18,827 $ (4,543 ) $ 1,023,784 Total debt securities $ 2,772,330 $ 13,390 $ (51,841 ) $ 2,733,879 $ 2,290,085 $ 22,224 $ (26,660 ) $ 2,285,649
Schedule of Fair Value of Available-for-sale and Held-to-maturity Debt Securities by Contractual Maturity	The following table presents the fair value of available-for-sale held-to-maturity March 31, 2018 (unaudited, in thousands) One Year or less One to Five Years Five to Ten Years After Ten Years Mortgage-backed securities Total Available-for-sale U.S. Treasury $ 9,894 $ — $ — $ — $ — $ 9,894 U.S. Government sponsored entities and agencies 9,945 1,961 16,671 6,864 61,017 96,458 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 1,344,410 1,344,410 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 140,926 140,926 Obligations of states and political subdivisions 3,686 17,368 40,161 40,216 — 101,431 Corporate debt securities 3,991 26,299 4,968 — — 35,258 Total available-for-sale $ 27,516 $ 45,628 $ 61,800 $ 47,080 $ 1,546,353 $ 1,728,377 Held-to-maturity (2) U.S. Government sponsored entities and agencies $ — $ — $ — $ — $ 10,890 $ 10,890 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — 158,218 158,218 Obligations of states and political subdivisions 6,872 114,768 398,845 282,723 — 803,208 Corporate debt securities — 7,504 25,682 — — 33,186 Total held-to-maturity $ 6,872 $ 122,272 $ 424,527 $ 282,723 $ 169,108 $ 1,005,502 Total debt securities $ 34,388 $ 167,900 $ 486,327 $ 329,803 $ 1,715,461 $ 2,733,879 (1) Mortgage-backed and collateralized mortgage securities, which have prepayment provisions, are not assigned to maturity categories due to fluctuations in their prepayment speeds. (2) The held-to-maturity
Schedule of Gross Realized Gains and Losses on the Sales and Calls of Securities as well as Gains and Losses on Equity Securities	The following table presents the gross realized gains and losses on sales and calls of available-for-sale held-to-maturity For the Three Months Ended March 31, (unaudited, in thousands) 2018 2017 Debt securities: Gross realized gains $ 7 $ 12 Gross realized losses (18 ) — Net (losses) gains on debt securities $ (11 ) $ 12 Equity securities: Unrealized (losses) gains recognized on securities still held $ (28 ) $ — Net realized (losses) gains recognized on securities sold — — Net (losses) gains on equity securities $ (28 ) $ — Net securities (losses) gains $ (39 ) $ 12
Schedule of Unrealized Losses on Debt Securities	The following tables provide information on unrealized losses on debt securities that have been in an unrealized loss position for less than twelve months and twelve months or more as of March 31, 2018 and December 31, 2017: March 31, 2018 Less than 12 months 12 months or more Total Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of (unaudited, dollars in thousands) Value Losses Securities Value Losses Securities Value Losses Securities U.S. Treasury $ 9,894 $ (6 ) 1 $ — $ — — $ 9,894 $ (6 ) 1 U.S. Government sponsored entities and agencies 59,280 (1,129 ) 8 41,203 (953 ) 8 100,483 (2,082 ) 16 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 785,806 (13,021 ) 128 602,202 (25,674 ) 195 1,388,008 (38,695 ) 323 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 101,309 (2,780 ) 12 23,376 (881 ) 4 124,685 (3,661 ) 16 Obligations of states and political subdivisions 335,762 (4,776 ) 527 72,751 (2,255 ) 152 408,513 (7,031 ) 679 Corporate debt securities 35,405 (352 ) 12 1,974 (14 ) 1 37,379 (366 ) 13 Total temporarily impaired securities $ 1,327,456 $ (22,064 ) 688 $ 741,506 $ (29,777 ) 360 $ 2,068,962 $ (51,841 ) 1,048 December 31, 2017 Less than 12 months 12 months or more Total Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of (unaudited, dollars in thousands) Value Losses Securities Value Losses Securities Value Losses Securities U.S. Government sponsored entities and agencies $ 24,776 $ (160 ) 4 $ 42,248 $ (771 ) 8 $ 67,024 $ (931 ) 12 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 423,794 (5,039 ) 87 637,461 (16,977 ) 193 1,061,255 (22,016 ) 280 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 79,061 (1,089 ) 10 27,852 (496 ) 6 106,913 (1,585 ) 16 Obligations of states and political subdivisions 132,831 (852 ) 210 77,554 (1,217 ) 160 210,385 (2,069 ) 370 Corporate debt securities 4,015 (19 ) 1 1,948 (40 ) 1 5,963 (59 ) 2 Total temporarily impaired securities $ 664,477 $ (7,159 ) 312 $ 787,063 $ (19,501 ) 368 $ 1,451,540 $ (26,660 ) 680

Loans and the Allowance for C23

Loans and the Allowance for Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Schedule of Recorded Investment in Loans by Category	The recorded investment in loans is presented in the Consolidated Balance Sheets net of deferred loan fees and costs, and discounts on purchased loans. The net deferred loan costs were $1.9 million and $1.6 million at March 31, 2018 and December 31, 2017, respectively. The unamortized discount on purchased loans from acquisitions was $20.8 million, including $10.0 million related to YCB, and $21.9 million at March 31, 2018 and December 31, 2017, respectively. (unaudited, in thousands) March 31, 2018 December 31, 2017 Commercial real estate: Land and construction $ 440,896 $ 392,597 Improved property 2,574,330 2,601,851 Total commercial real estate 3,015,226 2,994,448 Commercial and industrial 1,118,333 1,125,327 Residential real estate 1,345,993 1,353,301 Home equity 523,425 529,196 Consumer 319,561 339,169 Total portfolio loans 6,322,538 6,341,441 Loans held for sale 12,962 20,320 Total loans $ 6,335,500 $ 6,361,761
Summary of Changes in Allowance for Credit Losses	The following tables summarize changes in the allowance for credit losses applicable to each category of the loan portfolio: Allowance for Credit Losses By Category For the Three Months Ended March 31, 2018 and 2017 Commercial Commercial Real Estate- Real Estate- Land and Improved Commercial Residential Home Deposit (unaudited, in thousands) Construction Property & Industrial Real Estate Equity Consumer Overdraft Total Balance at December 31, 2017: Allowance for loan losses $ 3,117 $ 21,166 $ 9,414 $ 3,206 $ 4,497 $ 3,063 $ 821 $ 45,284 Allowance for loan commitments 119 26 173 7 212 37 — 574 Total beginning allowance for credit losses 3,236 21,192 9,587 3,213 4,709 3,100 821 45,858 Provision for credit losses: Provision for loan losses 1,090 (895 ) 919 202 262 583 (48 ) 2,113 Provision for loan commitments 57 (5 ) 3 — (4 ) 4 — 55 Total provision for credit losses 1,147 (900 ) 922 202 258 587 (48 ) 2,168 Charge-offs — (279 ) (109 ) (287 ) (576 ) (1,125 ) (267 ) (2,643 ) Recoveries 117 287 270 131 120 546 109 1,580 Net charge-offs 117 8 161 (156 ) (456 ) (579 ) (158 ) (1,063 ) Balance at March 31, 2018: Allowance for loan losses 4,324 20,279 10,494 3,252 4,303 3,067 615 46,334 Allowance for loan commitments 176 21 176 7 208 41 — 629 Total ending allowance for credit losses $ 4,500 $ 20,300 $ 10,670 $ 3,259 $ 4,511 $ 3,108 $ 615 $ 46,963 Balance at December 31, 2016: Allowance for loan losses $ 4,348 $ 18,628 $ 8,412 $ 4,106 $ 3,422 $ 3,998 $ 760 $ 43,674 Allowance for loan commitments 151 17 188 9 162 44 — 571 Total beginning allowance for credit losses 4,499 18,645 8,600 4,115 3,584 4,042 760 44,245 Provision for credit losses: Provision for loan losses (425 ) 983 832 330 365 583 66 2,734 Provision for loan commitments (8 ) — (31 ) 1 17 (2 ) — (23 ) Total provision for credit losses (433 ) 983 801 331 382 581 66 2,711 Charge-offs — (602 ) (880 ) (404 ) (108 ) (1,287 ) (338 ) (3,619 ) Recoveries 52 251 376 78 48 369 98 1,272 Net charge-offs 52 (351 ) (504 ) (326 ) (60 ) (918 ) (240 ) (2,347 ) Balance at March 31, 2017: Allowance for loan losses 3,975 19,260 8,740 4,110 3,727 3,663 586 44,061 Allowance for loan commitments 143 17 157 10 179 42 — 548 Total ending allowance for credit losses $ 4,118 $ 19,277 $ 8,897 $ 4,120 $ 3,906 $ 3,705 $ 586 $ 44,609
Allowance for Credit Losses and Recorded Investments in Loans	The following tables present the allowance for credit losses and recorded investments in loans by category: Allowance for Credit Losses and Recorded Investment in Loans Commercial Commercial Real Estate- Real Estate- Commercial Residential Deposit Land and Improved and Real Home Over- (unaudited, in thousands) Construction Property Industrial Estate Equity Consumer draft Total March 31, 2018 Allowance for credit losses: Allowance for loans individually evaluated for impairment $ — $ 387 $ — $ — $ — $ — $ — $ 387 Allowance for loans collectively evaluated for impairment 4,324 19,892 10,494 3,252 4,303 3,067 615 45,947 Allowance for loan commitments 176 21 176 7 208 41 — 629 Total allowance for credit losses $ 4,500 $ 20,300 $ 10,670 $ 3,259 $ 4,511 $ 3,108 $ 615 $ 46,963 Portfolio loans: Individually evaluated for impairment (1) $ — $ 2,104 $ — $ — $ — $ — $ — $ 2,104 Collectively evaluated for impairment 439,480 2,567,367 1,117,607 1,345,290 523,425 319,561 — 6,312,730 Acquired with deteriorated credit quality 1,416 4,859 726 703 — — — 7,704 Total portfolio loans $ 440,896 $ 2,574,330 $ 1,118,333 $ 1,345,993 $ 523,425 $ 319,561 $ — $ 6,322,538 December 31, 2017 Allowance for credit losses: Allowance for loans individually evaluated for impairment $ — $ 388 $ — $ — $ — $ — $ — $ 388 Allowance for loans collectively evaluated for impairment 3,117 20,778 9,414 3,206 4,497 3,063 821 44,896 Allowance for loan commitments 119 26 173 7 212 37 — 574 Total allowance for credit losses $ 3,236 $ 21,192 $ 9,587 $ 3,213 $ 4,709 $ 3,100 $ 821 $ 45,858 Portfolio loans: Individually evaluated for impairment (1) $ — $ 3,344 $ — $ — $ — $ — $ — $ 3,344 Collectively evaluated for impairment 391,140 2,593,393 1,124,544 1,352,587 529,196 339,163 — 6,330,023 Acquired with deteriorated credit quality 1,457 5,114 783 714 — 6 — 8,074 Total portfolio loans $ 392,597 $ 2,601,851 $ 1,125,327 $ 1,353,301 $ 529,196 $ 339,169 $ — $ 6,341,441 (1) Commercial loans greater than $1 million that are reported as non-accrual
Summary of Commercial Loans by Risk Grade	The following tables summarize commercial loans by their assigned risk grade: Commerical Loans by Internally Assigned Risk Grade (unaudited, in thousands) Commercial Commercial Commercial Total As of March 31, 2018 Pass $ 434,665 $ 2,526,334 $ 1,104,209 $ 4,065,208 Criticized - compromised 3,384 24,807 5,594 33,785 Classified - substandard 2,847 23,189 8,530 34,566 Classified - doubtful — — — — Total $ 440,896 $ 2,574,330 $ 1,118,333 $ 4,133,559 As of December 31, 2017 Pass $ 386,753 $ 2,548,805 $ 1,110,267 $ 4,045,825 Criticized - compromised 2,984 25,673 7,435 36,092 Classified - substandard 2,860 27,373 7,625 37,858 Classified - doubtful — — — — Total $ 392,597 $ 2,601,851 $ 1,125,327 $ 4,119,775
Summary of Changes in Accretable Yield for Loans Acquired with Deteriorated Credit Quality	The following table provides changes in accretable yield for loans acquired with deteriorated credit quality: For the Three Months Ended (unaudited, in thousands) March 31, March 31, Balance at beginning of period $ 1,724 $ 1,717 Acquisitions — — Reduction due to change in projected cash flows (86 ) (200 ) Reclass from non-accretable difference 2,841 174 Transfers out — — Accretion (268 ) (151 ) Balance at end of period $ 4,211 $ 1,540
Summary of Age Analysis of Loan Categories	The following tables summarize the age analysis of all categories of loans: Age Analysis of Loans (unaudited, in thousands) Current 30-59 Days Past Due 60-89 Days Past Due 90 Days or More Past Due Total Past Due Total Loans 90 Days or More Past Due and Accruing (1) As of March 31, 2018 Commercial real estate: Land and construction $ 439,926 $ — $ — $ 970 $ 970 $ 440,896 $ 172 Improved property 2,559,491 4,431 528 9,880 14,839 2,574,330 364 Total commercial real estate 2,999,417 4,431 528 10,850 15,809 3,015,226 536 Commercial and industrial 1,115,453 667 201 2,012 2,880 1,118,333 21 Residential real estate 1,333,175 3,860 1,618 7,340 12,818 1,345,993 561 Home equity 517,172 2,654 682 2,917 6,253 523,425 251 Consumer 316,517 1,950 432 662 3,044 319,561 210 Total portfolio loans 6,281,734 13,562 3,461 23,781 40,804 6,322,538 1,579 Loans held for sale 12,962 — — — — 12,962 — Total loans $ 6,294,696 $ 13,562 $ 3,461 $ 23,781 $ 40,804 $ 6,335,500 $ 1,579 Impaired loans included above are as follows: Non-accrual $ 8,120 $ 1,310 $ 754 $ 22,202 $ 24,266 $ 32,386 TDRs accruing interest (1) 6,435 230 193 — 423 6,858 Total impaired $ 14,555 $ 1,540 $ 947 $ 22,202 $ 24,689 $ 39,244 As of December 31, 2017 Commercial real estate: Land and construction $ 392,189 $ — $ 172 $ 236 $ 408 $ 392,597 $ — Improved property 2,589,704 374 1,200 10,573 12,147 2,601,851 243 Total commercial real estate 2,981,893 374 1,372 10,809 12,555 2,994,448 243 Commercial and industrial 1,121,957 572 196 2,602 3,370 1,125,327 20 Residential real estate 1,338,240 4,487 2,376 8,198 15,061 1,353,301 1,113 Home equity 522,584 2,135 683 3,794 6,612 529,196 742 Consumer 334,723 2,466 842 1,138 4,446 339,169 608 Total portfolio loans 6,299,397 10,034 5,469 26,541 42,044 6,341,441 2,726 Loans held for sale 20,320 — — — — 20,320 — Total loans $ 6,319,717 $ 10,034 $ 5,469 $ 26,541 $ 42,044 $ 6,361,761 $ 2,726 Impaired loans included above are as follows: Non-accrual $ 9,195 $ 1,782 $ 2,033 $ 23,815 $ 27,630 $ 36,825 TDRs accruing interest (1) 6,055 348 168 — 516 6,571 Total impaired $ 15,250 $ 2,130 $ 2,201 $ 23,815 $ 28,146 $ 43,396 (1) Loans 90 days or more past due and accruing interest exclude TDRs 90 days or more past due and accruing interest.
Summary of Impaired Loans	The following tables summarize impaired loans: Impaired Loans March 31, 2018 December 31, 2017 Unpaid Principal Balance (1) Recorded Investment Related Allowance Unpaid Principal Balance (1) Recorded Investment Related Allowance (unaudited, in thousands) With no related specific allowance recorded: Commercial real estate: Land and construction $ 873 $ 800 $ — $ 412 $ 239 $ — Improved property 14,554 10,319 — 18,229 12,863 — Commercial and industrial 3,045 2,496 — 3,745 3,086 — Residential real estate 19,601 17,751 — 20,821 18,982 — Home equity 5,771 4,971 — 5,833 5,169 — Consumer 918 803 — 1,084 952 — Total impaired loans without a specific allowance 44,762 37,140 — 50,124 41,291 — With a specific allowance recorded: Commercial real estate: Land and construction — — — — — — Improved property 2,104 2,104 387 2,105 2,105 388 Commercial and industrial — — — — — — Total impaired loans with a specific allowance 2,104 2,104 387 2,105 2,105 388 Total impaired loans $ 46,866 $ 39,244 $ 387 $ 52,229 $ 43,396 $ 388 (1) The difference between the unpaid principal balance and the recorded investment generally reflects amounts that have been previously charged-off Impaired Loans For the Three Months Ended March 31, 2018 For the Three Months Ended March 31, 2017 Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized (unaudited, in thousands) With no related specific allowance recorded: Commercial real estate: Land and construction $ 520 $ — $ 588 $ — Improved property 11,591 345 9,620 346 Commercial and industrial 2,791 2 3,812 2 Residential real estate 18,367 66 18,448 69 Home equity 5,070 5 4,186 5 Consumer 878 3 761 2 Total impaired loans without a specific allowance 39,217 421 37,415 424 With a specific allowance recorded: Commercial real estate: Land and construction — — — — Improved property 2,105 — 4,927 — Commercial and industrial — — 635 — Total impaired loans with a specific allowance 2,105 — 5,562 — Total impaired loans $ 41,322 $ 421 $ 42,977 $ 424
Recorded Investment in Non-Accrual Loans and TDRs	The following tables present the recorded investment in non-accrual Non-accrual (unaudited, in thousands) March 31, December 31, 2017 Commercial real estate: Land and construction $ 800 $ 239 Improved property 10,821 13,318 Total commercial real estate 11,621 13,557 Commercial and industrial 2,373 2,958 Residential real estate 13,149 14,661 Home equity 4,540 4,762 Consumer 703 887 Total $ 32,386 $ 36,825 (1) At March 31, 2018, there were 2 borrowers with loans greater than $1.0 million totaling $5.6 million, as compared to three borrowers with loans greater than $1.0 million totaling $6.8 million at December 31, 2017. Total non-accrual non-accrual TDRs March 31, 2018 December 31, 2017 (unaudited, in thousands) Accruing Non-Accrual Total Accruing Non-Accrual Total Commercial real estate: Land and construction $ — $ 2 $ 2 $ — $ 3 $ 3 Improved property 1,602 490 2,092 1,650 428 2,078 Total commercial real estate 1,602 492 2,094 1,650 431 2,081 Commercial and industrial 123 94 217 128 97 225 Residential real estate 4,602 1,525 6,127 4,321 1,880 6,201 Home equity 431 220 651 407 337 744 Consumer 100 66 166 65 120 185 Total $ 6,858 $ 2,397 $ 9,255 $ 6,571 $ 2,865 $ 9,436 As of March 31, 2018 and December 31, 2017 there were no TDRs greater than $1.0 million. The concessions granted in the majority of loans reported as accruing and non-accrual
Loans Identified as TDRs	The following tables present details related to loans identified as TDRs during the three months ended March 31, 2018 and 2017, respectively: New TDRs (1) For the Three Months Ended March 31, 2018 March 31, 2017 Pre- Post- Pre- Post- Modification Modification Modification Modification Outstanding Outstanding Outstanding Outstanding Number of Recorded Recorded Number of Recorded Recorded (unaudited, dollars in thousands) Modifications Investment Investment Modifications Investment Investment Commercial real estate: Land and construction — $ — $ — — $ — $ — Improved Property — — — — — — Total commercial real estate — — — — — — Commercial and industrial — — — 2 126 122 Residential real estate 5 203 195 1 10 9 Home equity — — — 1 44 43 Consumer 2 4 3 2 84 21 Total 7 $ 207 $ 198 6 $ 264 $ 195 (1) Excludes loans that were either paid off or charged-off pre-modification The following table summarizes TDRs which defaulted (defined as past due 90 days) during the three months ended March 31, 2018 and 2017, respectively, that were restructured within the last twelve months prior to March 31, 2018 and 2017, respectively: Defaulted TDRs (1) Defaulted TDRs (1) For the Three Months Ended For the Three Months Ended March 31, 2018 March 31, 2017 (unaudited, dollars in thousands) Number of Recorded Investment Number of Defaults Recorded Investment Commercial real estate: Land and construction — $ — — $ — Improved property — — — — Total commercial real estate — — — — Commercial and industrial — — — — Residential real estate 1 122 — — Home equity 1 7 — — Consumer — — 1 9 Total 2 $ 129 1 $ 9 (1) Excludes loans that were either charged-off
Summary of Other Real Estate Owned and Repossessed Assets	The following table summarizes other real estate owned and repossessed assets included in other assets: (unaudited, in thousands) March 31, December 31, Other real estate owned $ 3,991 $ 5,195 Repossessed assets 76 102 Total other real estate owned and repossessed assets $ 4,067 $ 5,297

Derivatives and Hedging Activ24

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Fair Values of Derivative Instruments on Balance Sheets	The table below presents the fair value of WesBanco’s derivative financial instruments as well as their classification on the Balance Sheet as of March 31, 2018 and December 31, 2017: March 31, 2018 December 31, 2017 (unaudited, in thousands) Notional or Contractual Asset Derivatives Liability Derivatives Notional or Contractual Amount Asset Derivatives Liability Derivatives Derivatives Loan Swaps: Interest rate swaps $ 309,242 $ 9,257 $ 9,083 $ 298,223 $ 7,351 $ 7,345 Other contracts: Interest rate loan commitments 24,730 147 — 20,319 49 — Best efforts forward delivery commitments 3,941 — 11 2,905 — 6 Forward TBA contracts 36,500 — 3 31,750 — 23 Total derivatives $ 9,404 $ 9,097 $ 7,400 $ 7,374
Summary of Effect of Derivative Instruments on Income Statement	The table below presents the change in the fair value of the Company’s derivative financial instruments reflected within the other non-interest For the Three Months Ended Location of Gain/(Loss) March 31, (unaudited, in thousands) 2018 2017 Interest rate swaps Other income $ (167 ) $ 195 Interest rate loan commitments Mortgage banking income 98 — Best efforts forward sales contracts Mortgage banking income (5 ) — Forward TBA contracts Mortgage banking income 410 — Total $ 336 $ 195

Pension Plan (Tables)

Pension Plan (Tables)	3 Months Ended
	Mar. 31, 2018
Retirement Benefits [Abstract]
Components of Net Periodic Pension Cost	The following table presents the net periodic pension cost for WesBanco’s Defined Benefit Pension Plan (the “Plan”) and the related components: For the Three Months Ended March 31, (unaudited, in thousands) 2018 2017 Service cost – benefits earned during year $ 699 $ 636 Interest cost on projected benefit obligation 1,114 1,084 Expected return on plan assets (2,204 ) (1,886 ) Amortization of prior service cost 6 6 Amortization of net loss 753 794 Net periodic pension cost $ 368 $ 634

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring and Nonrecurring Basis	The following tables set forth WesBanco’s financial assets and liabilities that were accounted for at fair value on a recurring and nonrecurring basis by level within the fair value hierarchy as of March 31, 2018 and December 31, 2017: March 31, 2018 Fair Value Measurements Using: March 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Investments Measured at Net Asset (unaudited, in thousands) (level 1) (level 2) (level 3) Value Recurring fair value measurements Equity securities $ 13,986 $ 11,568 $ — $ — $ 2,418 Debt securities - available-for-sale U.S. Treasury 9,894 — 9,894 — — U.S. Government sponsored entities and agencies 96,458 — 96,458 — — Residential mortgage-backed securities and collateralized mortgage obligations of government agencies 1,344,410 — 1,344,410 — — Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 140,926 — 140,926 — — Obligations of state and political subdivisions 101,431 — 101,431 — — Corporate debt securities 35,258 — 35,258 — — Total debt securities - available-for-sale $ 1,728,377 $ — $ 1,728,377 $ — $ — Loans held for sale 12,962 — 12,962 — — Other assets - interest rate derivatives agreements 9,257 — 9,257 — — Total assets recurring fair value measurements $ 1,764,582 $ 11,568 $ 1,750,596 $ — $ 2,418 Other liabilities - interest rate derivatives agreements $ 9,083 $ — $ 9,083 $ — $ — Total liabilities recurring fair value measurements $ 9,083 $ — $ 9,083 $ — $ — Nonrecurring fair value measurements Impaired loans $ 1,717 $ — $ — $ 1,717 $ — Other real estate owned and repossessed assets 4,067 — — 4,067 — Total nonrecurring fair value measurements $ 5,784 $ — $ — $ 5,784 $ — December 31, 2017 Fair Value Measurements Using: December 31, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Investments Measured at Net Asset (unaudited, in thousands) 2017 (level 1) (level 2) (level 3) Value Recurring fair value measurements Equity securities $ 13,457 $ 11,391 $ — $ — $ 2,066 Debt securities - available-for-sale U.S. Government sponsored entities and agencies 71,843 — 71,843 — — Residential mortgage-backed securities and collateralized mortgage obligations of government agencies 934,922 — 934,922 — — Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 114,867 — 114,867 — — Obligations of state and political subdivisions 104,830 — 104,830 — — Corporate debt securities 35,403 — 35,403 — — Total debt securities - available-for-sale $ 1,261,865 $ — $ 1,261,865 $ — $ — Loans held for sale 20,320 — 20,320 — — Other assets - interest rate derivatives agreements 7,351 — 7,351 — — Total assets recurring fair value measurements $ 1,302,993 $ 11,391 $ 1,289,536 $ — $ 2,066 Other liabilities - interest rate derivatives agreements $ 7,345 $ — $ 7,345 $ — $ — Total liabilities recurring fair value measurements $ 7,345 $ — $ 7,345 $ — $ — Nonrecurring fair value measurements Impaired loans $ 1,717 $ — $ — $ 1,717 $ — Other real estate owned and repossessed assets 5,297 — — 5,297 — Total nonrecurring fair value measurements $ 7,014 $ — $ — $ 7,014 $ —
Schedule of Assets Measured at Fair Value on Nonrecurring Basis	The following table presents additional quantitative information about assets measured at fair value on a nonrecurring basis and for which WesBanco has utilized level 3 inputs to determine fair value: Quantitative Information about Level 3 Fair Value Measurements Fair Value Valuation Unobservable Range (Weighted (unaudited, in thousands) Estimate Techniques Input Average) March 31, 2018 Impaired loans $ 1,717 Appraisal of collateral (1) Appraisal adjustments (2) (4.8%) / (4.8%) Liquidation expenses (2) (7.6%) / (7.6%) Other real estate owned and repossessed assets 4,067 Appraisal of collateral (1), (3) December 31, 2017: Impaired loans $ 1,717 Appraisal of collateral (1) Appraisal adjustments (2) (4.8%) / (4.8%) Liquidation expenses (2) (7.6%) / (7.6%) Other real estate owned and repossessed assets 5,297 Appraisal of collateral (1), (3) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of appraisal adjustments and liquidation expenses are presented as a percent of the appraisal. (3) Includes estimated liquidation expenses and numerous dissimilar qualitative adjustments by management which are not identifiable.
Estimates Fair Values of Financial Instruments	The estimated fair values of WesBanco’s financial instruments are summarized below: Fair Value Measurements at March 31, 2018 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Active Markets for Identical Assets (level 1) Significant Other Observable Inputs (level 2) Significant Unobservable Inputs (level 3) Investments Measured at Net Asset Value Financial Assets Cash and due from banks $ 100,845 $ 100,845 $ 100,845 $ — $ — $ — Equity securities 13,986 13,986 11,568 — — 2,418 Debt securities available-for-sale 1,728,377 1,728,377 — 1,728,377 — — Debt securities held-to-maturity 1,006,042 1,005,502 — 1,004,912 590 — Net loans 6,276,204 6,158,399 — — 6,158,399 — Loans held for sale 12,962 12,962 — 12,962 — — Other assets - interest rate derivatives 9,257 9,257 — 9,257 — — Accrued interest receivable 31,963 31,963 31,963 — — — Financial Liabilities Deposits 7,226,326 7,230,335 6,018,657 1,211,678 — — Federal Home Loan Bank borrowings 1,166,939 1,161,442 — 1,161,442 — — Other borrowings 207,653 207,627 205,651 1,976 — — Subordinated debt and junior subordinated debt 164,379 149,887 — 149,887 — — Other liabilities - interest rate derivatives 9,083 9,083 — 9,083 — — Accrued interest payable 4,033 4,033 4,033 — — — Fair Value Measurements at December 31, 2017 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Active Markets for Identical Assets (level 1) Significant Other Observable Inputs (level 2) Significant Unobservable Inputs (level 3) Investments Measured at Net Asset Value Financial Assets Cash and due from banks $ 117,572 $ 117,572 $ 117,572 $ — $ — $ — Equity securities 13,457 13,457 11,391 — — 2,066 Debt securities available-for-sale 1,261,865 1,261,865 — 1,261,865 — — Debt securities held-to-maturity 1,009,500 1,023,784 — 1,023,191 593 — Net loans 6,296,157 6,212,823 — — 6,212,823 — Loans held for sale 20,320 20,320 — 20,320 — — Other assets - interest rate derivatives 7,351 7,351 — 7,351 — — Accrued interest receivable 29,728 29,728 29,728 — — — Financial Liabilities Deposits 7,043,588 7,053,536 5,766,531 1,287,005 — — Federal Home Loan Bank borrowings 948,203 944,706 — 944,706 — — Other borrowings 184,805 184,814 182,785 2,029 — — Subordinated debt and junior subordinated debt 164,327 146,484 — 146,484 — — Other liabilities - interest rate derivatives 7,345 7,345 — 7,345 — — Accrued interest payable 3,178 3,178 3,178 — — —

Revenue Recognition (Tables)

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2018
Text Block [Abstract]
Summary of Revenue Recognition	The following table summarizes the point of revenue recognition and the income recognized for each of the revenue streams for the three months ended March 31, 2018: (unaudited, in thousands) Point of Revenue Recognition For the Three Months Ended March 31, 2018 Revenue Streams Trust Fees Trust account fees Over time $ 4,292 WesMark fees Over time 2,211 Total trust fees 6,503 Service charges on deposits Commercial banking fees Over time 407 Personal service charges At a point in time & Over time 4,415 Total service charges on deposits 4,822 Net securities brokerage revenue Annuity commissions At a point in time 1,200 Equity and debt security trades At a point in time 102 Managed money Over time 141 Trail commissions Over time 227 Total net securities brokerage revenue 1,670 Electronic banking fees At a point in time 4,829 Mortgage banking income At a point in time 1,004 Gain/loss on sale of OREO/other assets At a point in time 262

Comprehensive Income_(Loss) (Ta

Comprehensive Income/(Loss) (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Components of Accumulated Other Comprehensive Income	The activity in accumulated other comprehensive income for the three months ended March 31, 2018 and 2017 is as follows: Accumulated Other Comprehensive Income/(Loss) (1) (unaudited, in thousands) Defined Unrealized Gains (Losses) on Debt Securities Available-for-Sale Unrealized Gains on Debt Securities Transferred from Available-for-Sale to Held-to-Maturity Total Balance at December 31, 2017 $ (18,626 ) $ (13,250 ) $ 381 $ (31,495 ) Other comprehensive income before reclassifications — (14,905 ) — (14,905 ) Amounts reclassified from accumulated other comprehensive income 437 — (50 ) 387 Period change 437 (14,905 ) (50 ) (14,518 ) Adoption of Accounting Standard ASU 2016-01 — (1,063 ) — (1,063 ) Balance at March 31, 2018 $ (18,189 ) $ (29,218 ) $ 331 $ (47,076 ) Balance at December 31, 2016 $ (17,758 ) $ (9,890 ) $ 522 $ (27,126 ) Other comprehensive income before reclassifications — 1,680 — 1,680 Amounts reclassified from accumulated other comprehensive income 655 — (50 ) 605 Period change 655 1,680 (50 ) 2,285 Balance at March 31, 2017 $ (17,103 ) $ (8,210 ) $ 472 $ (24,841 ) (1) All amounts are net of tax. Related income tax expense or benefit is calculated using a combined Federal and State income tax rate approximating 23% in 2018 and 37% in all prior periods. (2) See Note 1, Summary of Significant Accounting Policies for additional information about WesBanco’s adoption of ASU 2016-01.
Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income	The following table provides details about amounts reclassified from accumulated other comprehensive income for the three months ended March 31, 2018 and 2017: Details about Accumulated Other Comprehensive Income/(Loss) Components Amounts Reclassified from Accumulated Other Comprehensive Income/(Loss) For the Three Months Ended March 31, Affected Line Item in the Statement of Net Income (unaudited, in thousands) 2018 2017 Debt securities available-for-sale (1) Net securities gains reclassified into earnings $ — $ — Net securities gains (Non-interest Related income tax expense — — Provision for income taxes Net effect on accumulated other comprehensive income for the period — — Debt securities held-to-maturity (1) Amortization of unrealized gain transferred from available-for-sale (66 ) (72 ) Interest and dividends on securities (Interest and dividend income) Related income tax expense 16 22 Provision for income taxes Net effect on accumulated other comprehensive income for the period (50 ) (50 ) Defined benefit pension plan (2) Amortization of net loss and prior service costs 756 801 Employee benefits (Non-interest Related income tax benefit (319 ) (146 ) Provision for income taxes Net effect on accumulated other comprehensive income for the period 437 655 Total reclassifications for the period $ 387 $ 605 (1) For additional detail related to unrealized gains on securities and related amounts reclassified from accumulated other comprehensive income, see Note 3, “Securities.” (2) Included in the computation of net periodic pension cost. See Note 6, “Pension Plan” for additional detail.

Commitments and Contingent Li29

Commitments and Contingent Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments to Extend Credit, Guarantees and Various Letters of Credit Outstanding	The following table presents total commitments to extend credit, guarantees and various letters of credit outstanding: March 31, December 31, (unaudited, in thousands) 2018 2017 Lines of credit $ 1,464,970 $ 1,452,697 Loans approved but not closed 358,367 245,644 Overdraft limits 124,752 126,671 Letters of credit 31,947 31,951 Contingent obligations and other guarantees 6,796 6,700

Business Segments (Tables)

Business Segments (Tables)	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
Financial Information by Business Segment	Condensed financial information by business segment is presented below: Trust and Community Investment (unaudited, in thousands) Banking Services Consolidated For the Three Months ended March 31, 2018: Interest and dividend income $ 86,417 $ — $ 86,417 Interest expense 13,125 — 13,125 Net interest income 73,292 — 73,292 Provision for credit losses 2,168 — 2,168 Net interest income after provision for credit losses 71,124 — 71,124 Non-interest 17,477 6,503 23,980 Non-interest 50,894 3,677 54,571 Income before provision for income taxes 37,707 2,826 40,533 Provision for income taxes 6,411 593 7,004 Net income $ 31,296 $ 2,233 $ 33,529 For the Three Months ended March 31, 2017: Interest and dividend income $ 79,924 $ — $ 79,924 Interest expense 9,205 — 9,205 Net interest income 70,719 — 70,719 Provision for credit losses 2,711 — 2,711 Net interest income after provision for credit losses 68,008 — 68,008 Non-interest 16,741 6,143 22,884 Non-interest 50,992 3,392 54,384 Income before provision for income taxes 33,757 2,751 36,508 Provision for income taxes 9,522 1,100 10,622 Net income $ 24,235 $ 1,651 $ 25,886

Summary of Significant Accoun31

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Service cost component of defined benefit plan		$ 699	$ 636
Accounting Standards Update 2016-01 [Member]
Summary Of Significant Accounting Policies [Line Items]
Adjustment to retained earnings	$ 1,100

Earnings Per Common Share - Sum

Earnings Per Common Share - Summary of Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator for both basic and diluted earnings per common share:
Net income	$ 33,529	$ 25,886
Denominator:
Total average basic common shares outstanding	44,050,701	43,947,563
Effect of dilutive stock options and other stock compensation	117,541	73,202
Total diluted average common shares outstanding	44,168,242	44,020,765
Earnings per common share - basic	$ 0.76	$ 0.59
Earnings per common share - diluted	$ 0.76	$ 0.59

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares contingently issuable under shareholder return plan	39,216	0
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities excluded from computation of net income per diluted shares	9,000	0

Securities - Schedule of Fair V

Securities - Schedule of Fair Value and Amortized Cost of Available-for-sale and Held-to-maturity Debt Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	$ 1,766,288	$ 1,280,585
Available-for-sale, Gross Unrealized Gains	2,497	3,397
Available-for-sale, Gross Unrealized Losses	(40,408)	(22,117)
Available-for-sale, Estimated Fair Value	1,728,377	1,261,865
Held-to-maturity, Amortized Cost	1,006,042	1,009,500
Held-to-maturity, Gross Unrealized Gains	10,893	18,827
Held-to-maturity, Gross Unrealized Losses	(11,433)	(4,543)
Held-to-maturity securities, Fair value	1,005,502	1,023,784
Total securities, Amortized Cost	2,772,330	2,290,085
Total securities, Gross Unrealized Gains	13,390	22,224
Total securities, Gross Unrealized Losses	(51,841)	(26,660)
Total securities, Estimated Fair Value	2,733,879	2,285,649
US Treasury Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	9,900
Available-for-sale, Gross Unrealized Losses	(6)
Available-for-sale, Estimated Fair Value	9,894
U.S. Government Sponsored Entities and Agencies [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	98,166	72,425
Available-for-sale, Gross Unrealized Gains	1	24
Available-for-sale, Gross Unrealized Losses	(1,709)	(606)
Available-for-sale, Estimated Fair Value	96,458	71,843
Held-to-maturity, Amortized Cost	11,263	11,465
Held-to-maturity, Gross Unrealized Losses	(373)	(325)
Held-to-maturity securities, Fair value	10,890	11,140
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	1,377,904	954,115
Available-for-sale, Gross Unrealized Gains	214	214
Available-for-sale, Gross Unrealized Losses	(33,708)	(19,407)
Available-for-sale, Estimated Fair Value	1,344,410	934,922
Held-to-maturity, Amortized Cost	162,904	170,025
Held-to-maturity, Gross Unrealized Gains	301	544
Held-to-maturity, Gross Unrealized Losses	(4,987)	(2,609)
Held-to-maturity securities, Fair value	158,218	167,960
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	144,568	116,448
Available-for-sale, Gross Unrealized Gains	19	4
Available-for-sale, Gross Unrealized Losses	(3,661)	(1,585)
Available-for-sale, Estimated Fair Value	140,926	114,867
Obligations of State and Political Subdivisions [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	100,531	102,363
Available-for-sale, Gross Unrealized Gains	2,093	2,927
Available-for-sale, Gross Unrealized Losses	(1,193)	(460)
Available-for-sale, Estimated Fair Value	101,431	104,830
Held-to-maturity, Amortized Cost	798,536	794,655
Held-to-maturity, Gross Unrealized Gains	10,510	17,364
Held-to-maturity, Gross Unrealized Losses	(5,838)	(1,609)
Held-to-maturity securities, Fair value	803,208	810,410
Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale, Amortized Cost	35,219	35,234
Available-for-sale, Gross Unrealized Gains	170	228
Available-for-sale, Gross Unrealized Losses	(131)	(59)
Available-for-sale, Estimated Fair Value	35,258	35,403
Held-to-maturity, Amortized Cost	33,339	33,355
Held-to-maturity, Gross Unrealized Gains	82	919
Held-to-maturity, Gross Unrealized Losses	(235)
Held-to-maturity securities, Fair value	$ 33,186	$ 34,274

Securities - Additional Informa

Securities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)Holdings	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)Holdings
Investments, Debt and Equity Securities [Abstract]
Maximum percentage of equity of one issuer	10.00%
Number of holdings greater than specified percentage of equity | Holdings	0		0
Equities securities	$ 13,986,000		$ 13,457,000
Securities with aggregate fair values	1,500,000,000		1,400,000,000
Net unrealized losses on available-for-sale debt securities included in AOCI	29,200,000		13,300,000
Sales of available-for-sale debt securities	0	$ 0
Impairment loss relating to securities	0
Federal home loan bank stock, Total	$ 55,600,000		$ 45,900,000

Securities - Schedule of Fair36

Securities - Schedule of Fair Value of Available-for-Sale and Held-to-Maturity Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, One Year or less	$ 27,516
Total available-for-sale securities, One to Five Years	45,628
Total available-for-sale securities, Five to Ten Years	61,800
Total available-for-sale securities, After Ten Years	47,080
Total available-for-sale securities, Mortgage-backed	1,546,353
Available-for-sale, Estimated Fair Value	1,728,377	$ 1,261,865
Total held-to-maturity securities, One Year or less	6,872
Total held-to-maturity securities, One to Five Years	122,272
Total held-to-maturity securities, Five to Ten Years	424,527
Total held-to-maturity securities, After Ten Years	282,723
Total held-to-maturity securities, Mortgage-backed	169,108
Held-to-maturity securities, Fair value	1,005,502	1,023,784
Total, One Year or less	34,388
Total, One to Five Years	167,900
Total, Five to Ten Years	486,327
Total, After Ten Years, Fair value	329,803
Total, Mortgage-backed	1,715,461
Total, Fair value	2,733,879	2,285,649
US Treasury Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, One Year or less	9,894
Available-for-sale, Estimated Fair Value	9,894
U.S. Government Sponsored Entities and Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, One Year or less	9,945
Total available-for-sale securities, One to Five Years	1,961
Total available-for-sale securities, Five to Ten Years	16,671
Total available-for-sale securities, After Ten Years	6,864
Total available-for-sale securities, Mortgage-backed	61,017
Available-for-sale, Estimated Fair Value	96,458	71,843
Total held-to-maturity securities, Mortgage-backed	10,890
Held-to-maturity securities, Fair value	10,890	11,140
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, Mortgage-backed	1,344,410
Available-for-sale, Estimated Fair Value	1,344,410	934,922
Total held-to-maturity securities, Mortgage-backed	158,218
Held-to-maturity securities, Fair value	158,218	167,960
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, Mortgage-backed	140,926
Available-for-sale, Estimated Fair Value	140,926	114,867
Obligations of State and Political Subdivisions [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, One Year or less	3,686
Total available-for-sale securities, One to Five Years	17,368
Total available-for-sale securities, Five to Ten Years	40,161
Total available-for-sale securities, After Ten Years	40,216
Available-for-sale, Estimated Fair Value	101,431	104,830
Total held-to-maturity securities, One Year or less	6,872
Total held-to-maturity securities, One to Five Years	114,768
Total held-to-maturity securities, Five to Ten Years	398,845
Total held-to-maturity securities, After Ten Years	282,723
Held-to-maturity securities, Fair value	803,208	810,410
Corporate Debt Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Total available-for-sale securities, One Year or less	3,991
Total available-for-sale securities, One to Five Years	26,299
Total available-for-sale securities, Five to Ten Years	4,968
Available-for-sale, Estimated Fair Value	35,258	35,403
Total held-to-maturity securities, One to Five Years	7,504
Total held-to-maturity securities, Five to Ten Years	25,682
Held-to-maturity securities, Fair value	$ 33,186	$ 34,274

Securities - Schedule of Fair37

Securities - Schedule of Fair Value of Available-for-Sale and Held-to-Maturity Debt Securities by Contractual Maturity (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Amortized Cost and Fair Value Debt Securities [Abstract]
Held-to-maturity, Amortized Cost	$ 1,006,042	$ 1,009,500

Securities - Schedule of Gross

Securities - Schedule of Gross Realized Gains and Losses on the Sales and Calls of Securities as well as Gains and Losses on Equity Securities (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Available-for-Sale Securities, Gross Unrealized Gain (Loss) [Line Items]
Net securities (losses) gains	$ (39)	$ 12
Debt Securities [Member]
Available-for-Sale Securities, Gross Unrealized Gain (Loss) [Line Items]
Gross realized gains	7	12
Gross realized losses	(18)
Net (losses) gains on debt securities	(11)	12
Equity Securities [Member]
Available-for-Sale Securities, Gross Unrealized Gain (Loss) [Line Items]
Unrealized (losses) gains recognized on securities still held	(28)
Net realized (losses) gains recognized on securities sold	0	$ 0
Net (losses) gains on equity securities	$ (28)

Securities - Schedule of Unreal

Securities - Schedule of Unrealized Losses on Debt Securities (Detail) $ in Thousands	Mar. 31, 2018USD ($)Security	Dec. 31, 2017USD ($)Security
US Treasury Securities [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 9,894
Less than 12 months, Unrealized Losses	$ (6)
Less than 12 months, Number of Securities | Security	1
Fair Value, Total	$ 9,894
Unrealized Losses, Total	$ (6)
Number of Securities Total | Security	1
U.S. Government Sponsored Entities and Agencies [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 59,280	$ 24,776
Less than 12 months, Unrealized Losses	$ (1,129)	$ (160)
Less than 12 months, Number of Securities | Security	8	4
12 months or more, Fair Value	$ 41,203	$ 42,248
12 months or more, Unrealized Losses	$ (953)	$ (771)
12 months or more, Number of Securities | Security	8	8
Fair Value, Total	$ 100,483	$ 67,024
Unrealized Losses, Total	$ (2,082)	$ (931)
Number of Securities Total | Security	16	12
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 785,806	$ 423,794
Less than 12 months, Unrealized Losses	$ (13,021)	$ (5,039)
Less than 12 months, Number of Securities | Security	128	87
12 months or more, Fair Value	$ 602,202	$ 637,461
12 months or more, Unrealized Losses	$ (25,674)	$ (16,977)
12 months or more, Number of Securities | Security	195	193
Fair Value, Total	$ 1,388,008	$ 1,061,255
Unrealized Losses, Total	$ (38,695)	$ (22,016)
Number of Securities Total | Security	323	280
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 101,309	$ 79,061
Less than 12 months, Unrealized Losses	$ (2,780)	$ (1,089)
Less than 12 months, Number of Securities | Security	12	10
12 months or more, Fair Value	$ 23,376	$ 27,852
12 months or more, Unrealized Losses	$ (881)	$ (496)
12 months or more, Number of Securities | Security	4	6
Fair Value, Total	$ 124,685	$ 106,913
Unrealized Losses, Total	$ (3,661)	$ (1,585)
Number of Securities Total | Security	16	16
Obligations of State and Political Subdivisions [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 335,762	$ 132,831
Less than 12 months, Unrealized Losses	$ (4,776)	$ (852)
Less than 12 months, Number of Securities | Security	527	210
12 months or more, Fair Value	$ 72,751	$ 77,554
12 months or more, Unrealized Losses	$ (2,255)	$ (1,217)
12 months or more, Number of Securities | Security	152	160
Fair Value, Total	$ 408,513	$ 210,385
Unrealized Losses, Total	$ (7,031)	$ (2,069)
Number of Securities Total | Security	679	370
Corporate Debt Securities [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 35,405	$ 4,015
Less than 12 months, Unrealized Losses	$ (352)	$ (19)
Less than 12 months, Number of Securities | Security	12	1
12 months or more, Fair Value	$ 1,974	$ 1,948
12 months or more, Unrealized Losses	$ (14)	$ (40)
12 months or more, Number of Securities | Security	1	1
Fair Value, Total	$ 37,379	$ 5,963
Unrealized Losses, Total	$ (366)	$ (59)
Number of Securities Total | Security	13	2
Total Temporarily Impaired Securities [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 1,327,456	$ 664,477
Less than 12 months, Unrealized Losses	$ (22,064)	$ (7,159)
Less than 12 months, Number of Securities | Security	688	312
12 months or more, Fair Value	$ 741,506	$ 787,063
12 months or more, Unrealized Losses	$ (29,777)	$ (19,501)
12 months or more, Number of Securities | Security	360	368
Fair Value, Total	$ 2,068,962	$ 1,451,540
Unrealized Losses, Total	$ (51,841)	$ (26,660)
Number of Securities Total | Security	1,048	680

Loans and the Allowance for C40

Loans and the Allowance for Credit Losses - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)Contract	Dec. 31, 2017USD ($)Contract	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Financing Receivable, Recorded Investment [Line Items]
Deferred loan (costs) and fees	$ 1,900,000	$ 1,600,000
Unamortized discount on purchased loans from acquisitions	20,800,000	21,900,000
Aggregate amount of residential real estate, home equity and consumer loans classified as substandard	19,400,000	22,800,000
Internally assigned loan grades to residential real estate, home equity and consumer loans	1,000,000	2,500,000
Loans acquired with deteriorated credit quality	7,704,000	8,074,000
Allowance for loan losses	$ 46,334,000	$ 45,284,000	$ 44,061,000	$ 43,674,000
Number of restructured contracts greater than $1 million | Contract	0	0
Threshold for TDR	$ 1,000,000	$ 1,000,000
Accruing and non accrual TDR permitted interest-only payment period	3 months
Unfunded commitments to debtors for impaired loans	$ 100,000	100,000
Other real estate owned	3,991,000	5,195,000
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans acquired with deteriorated credit quality	726,000	783,000
Allowance for loan losses	10,494,000	9,414,000	8,740,000	8,412,000
Commercial and Industrial [Member] | Maximum [Member]
Financing Receivable, Recorded Investment [Line Items]
Annual sales of borrowers	100,000,000
Your Community Bankshares, Inc [Member]
Financing Receivable, Recorded Investment [Line Items]
Unamortized discount on purchased loans from acquisitions	10,000,000
Loans acquired with deteriorated credit quality	4,200,000	4,300,000
Loans acquired accretable	1,300,000
Allowance for loan losses	200,000	0
Your Community Bankshares, Inc [Member] | Cost Recovery Method [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of acquired loans	700,000	800,000
ESB Financial Corporation [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans acquired with deteriorated credit quality	3,500,000	3,700,000
Loans acquired accretable	2,900,000
Allowance for loan losses	2,000,000	2,000,000
ESB Financial Corporation [Member] | Cost Recovery Method [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of acquired loans	3,500,000	3,500,000
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans acquired with deteriorated credit quality	703,000	714,000
Allowance for loan losses	3,252,000	3,206,000	$ 4,110,000	$ 4,106,000
Other real estate owned	900,000	1,500,000
Foreclosure proceedings in process on residential real estate loans	$ 4,300,000	$ 3,500,000

Loans and the Allowance for C41

Loans and the Allowance for Credit Losses - Schedule of Recorded Investment in Loans by Category (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 6,322,538	$ 6,341,441
Loans held for sale	12,962	20,320
Total loans	6,335,500	6,361,761
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	440,896	392,597
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	2,574,330	2,601,851
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,118,333	1,125,327
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	3,015,226	2,994,448
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,345,993	1,353,301
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	319,561	339,169
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 523,425	$ 529,196

Loans and the Allowance for C42

Loans and the Allowance for Credit Losses - Summary of Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	$ 45,284	$ 43,674
Allowance for loan commitments, beginning balance	574	571
Total beginning allowance for credit losses	45,858	44,245
Provision for loan losses	2,113	2,734
Provision for loan commitments	55	(23)
Total provision for credit losses	2,168	2,711
Charge-offs	(2,643)	(3,619)
Recoveries	1,580	1,272
Net charge-offs	(1,063)	(2,347)
Allowance for loan losses, ending balance	46,334	44,061
Allowance for loan commitments, ending balance	629	548
Total ending allowance for credit losses	46,963	44,609
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	3,117	4,348
Allowance for loan commitments, beginning balance	119	151
Total beginning allowance for credit losses	3,236	4,499
Provision for loan losses	1,090	(425)
Provision for loan commitments	57	(8)
Total provision for credit losses	1,147	(433)
Recoveries	117	52
Net charge-offs	117	52
Allowance for loan losses, ending balance	4,324	3,975
Allowance for loan commitments, ending balance	176	143
Total ending allowance for credit losses	4,500	4,118
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	21,166	18,628
Allowance for loan commitments, beginning balance	26	17
Total beginning allowance for credit losses	21,192	18,645
Provision for loan losses	(895)	983
Provision for loan commitments	(5)
Total provision for credit losses	(900)	983
Charge-offs	(279)	(602)
Recoveries	287	251
Net charge-offs	8	(351)
Allowance for loan losses, ending balance	20,279	19,260
Allowance for loan commitments, ending balance	21	17
Total ending allowance for credit losses	20,300	19,277
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	9,414	8,412
Allowance for loan commitments, beginning balance	173	188
Total beginning allowance for credit losses	9,587	8,600
Provision for loan losses	919	832
Provision for loan commitments	3	(31)
Total provision for credit losses	922	801
Charge-offs	(109)	(880)
Recoveries	270	376
Net charge-offs	161	(504)
Allowance for loan losses, ending balance	10,494	8,740
Allowance for loan commitments, ending balance	176	157
Total ending allowance for credit losses	10,670	8,897
Deposit Overdraft [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	821	760
Total beginning allowance for credit losses	821	760
Provision for loan losses	(48)	66
Total provision for credit losses	(48)	66
Charge-offs	(267)	(338)
Recoveries	109	98
Net charge-offs	(158)	(240)
Allowance for loan losses, ending balance	615	586
Total ending allowance for credit losses	615	586
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	3,206	4,106
Allowance for loan commitments, beginning balance	7	9
Total beginning allowance for credit losses	3,213	4,115
Provision for loan losses	202	330
Provision for loan commitments		1
Total provision for credit losses	202	331
Charge-offs	(287)	(404)
Recoveries	131	78
Net charge-offs	(156)	(326)
Allowance for loan losses, ending balance	3,252	4,110
Allowance for loan commitments, ending balance	7	10
Total ending allowance for credit losses	3,259	4,120
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	3,063	3,998
Allowance for loan commitments, beginning balance	37	44
Total beginning allowance for credit losses	3,100	4,042
Provision for loan losses	583	583
Provision for loan commitments	4	(2)
Total provision for credit losses	587	581
Charge-offs	(1,125)	(1,287)
Recoveries	546	369
Net charge-offs	(579)	(918)
Allowance for loan losses, ending balance	3,067	3,663
Allowance for loan commitments, ending balance	41	42
Total ending allowance for credit losses	3,108	3,705
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, beginning balance	4,497	3,422
Allowance for loan commitments, beginning balance	212	162
Total beginning allowance for credit losses	4,709	3,584
Provision for loan losses	262	365
Provision for loan commitments	(4)	17
Total provision for credit losses	258	382
Charge-offs	(576)	(108)
Recoveries	120	48
Net charge-offs	(456)	(60)
Allowance for loan losses, ending balance	4,303	3,727
Allowance for loan commitments, ending balance	208	179
Total ending allowance for credit losses	$ 4,511	$ 3,906

Loans and the Allowance for C43

Loans and the Allowance for Credit Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans individually evaluated for impairment	$ 387	$ 388
Allowance for loans collectively evaluated for impairment	45,947	44,896
Allowance for loan commitments	629	574	$ 548	$ 571
Total allowance for credit losses	46,963	45,858	44,609	44,245
Individually evaluated for impairment	2,104	3,344
Collectively evaluated for impairment	6,312,730	6,330,023
Acquired with deteriorated credit quality	7,704	8,074
Total loans	6,322,538	6,341,441
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	4,324	3,117
Allowance for loan commitments	176	119	143	151
Total allowance for credit losses	4,500	3,236	4,118	4,499
Collectively evaluated for impairment	439,480	391,140
Acquired with deteriorated credit quality	1,416	1,457
Total loans	440,896	392,597
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans individually evaluated for impairment	387	388
Allowance for loans collectively evaluated for impairment	19,892	20,778
Allowance for loan commitments	21	26	17	17
Total allowance for credit losses	20,300	21,192	19,277	18,645
Individually evaluated for impairment	2,104	3,344
Collectively evaluated for impairment	2,567,367	2,593,393
Acquired with deteriorated credit quality	4,859	5,114
Total loans	2,574,330	2,601,851
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	10,494	9,414
Allowance for loan commitments	176	173	157	188
Total allowance for credit losses	10,670	9,587	8,897	8,600
Collectively evaluated for impairment	1,117,607	1,124,544
Acquired with deteriorated credit quality	726	783
Total loans	1,118,333	1,125,327
Deposit Overdraft [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	615	821
Total allowance for credit losses	615	821	586	760
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	3,252	3,206
Allowance for loan commitments	7	7	10	9
Total allowance for credit losses	3,259	3,213	4,120	4,115
Collectively evaluated for impairment	1,345,290	1,352,587
Acquired with deteriorated credit quality	703	714
Total loans	1,345,993	1,353,301
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	3,067	3,063
Allowance for loan commitments	41	37	42	44
Total allowance for credit losses	3,108	3,100	3,705	4,042
Collectively evaluated for impairment	319,561	339,163
Acquired with deteriorated credit quality		6
Total loans	319,561	339,169
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	4,303	4,497
Allowance for loan commitments	208	212	179	162
Total allowance for credit losses	4,511	4,709	$ 3,906	$ 3,584
Collectively evaluated for impairment	523,425	529,196
Total loans	$ 523,425	$ 529,196

Loans and the Allowance for C44

Loans and the Allowance for Credit Losses - Allowance for Credit Losses and Recorded Investments in Loans (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Troubled debt restructuring threshold	$ 1	$ 1

Loans and the Allowance for C45

Loans and the Allowance for Credit Losses - Summary of Commercial Loans by Risk Grade (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Summary of commercial loans by risk grade
Commercial loans	$ 6,276,204	$ 6,296,157
Commercial Portfolio Segment [Member]
Summary of commercial loans by risk grade
Commercial loans	4,133,559	4,119,775
Commercial Portfolio Segment [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	4,065,208	4,045,825
Commercial Portfolio Segment [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	33,785	36,092
Commercial Portfolio Segment [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	34,566	37,858
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member]
Summary of commercial loans by risk grade
Commercial loans	440,896	392,597
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	434,665	386,753
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	3,384	2,984
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	2,847	2,860
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member]
Summary of commercial loans by risk grade
Commercial loans	2,574,330	2,601,851
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	2,526,334	2,548,805
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	24,807	25,673
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	23,189	27,373
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Summary of commercial loans by risk grade
Commercial loans	1,118,333	1,125,327
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	1,104,209	1,110,267
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	5,594	7,435
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	$ 8,530	$ 7,625

Loans and the Allowance for C46

Loans and the Allowance for Credit Losses - Summary of Changes in Accretable Yield for Loans Acquired with Deteriorated Credit Quality (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period [Abstract]
Balance at beginning of period	$ 1,724	$ 1,717
Acquisitions	0	0
Reduction due to change in projected cash flows	(86)	(200)
Reclass from non-accretable difference	2,841	174
Transfers out	0	0
Accretion	(268)	(151)
Balance at end of period	$ 4,211	$ 1,540

Loans and the Allowance for C47

Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Current	$ 6,281,734	$ 6,299,397
Total Past Due	40,804	42,044
Total loans	6,322,538	6,341,441
90 Days or More Past Due and Accruing	1,579	2,726
Loans held for sale, current	12,962	20,320
Loans held for sale	12,962	20,320
Total loans, current	6,294,696	6,319,717
Total loans	6,335,500	6,361,761
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	517,172	522,584
Total Past Due	6,253	6,612
Total loans	523,425	529,196
90 Days or More Past Due and Accruing	251	742
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	2,999,417	2,981,893
Total Past Due	15,809	12,555
Total loans	3,015,226	2,994,448
90 Days or More Past Due and Accruing	536	243
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	1,333,175	1,338,240
Total Past Due	12,818	15,061
Total loans	1,345,993	1,353,301
90 Days or More Past Due and Accruing	561	1,113
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	316,517	334,723
Total Past Due	3,044	4,446
Total loans	319,561	339,169
90 Days or More Past Due and Accruing	210	608
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	439,926	392,189
Total Past Due	970	408
Total loans	440,896	392,597
90 Days or More Past Due and Accruing	172
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	2,559,491	2,589,704
Total Past Due	14,839	12,147
Total loans	2,574,330	2,601,851
90 Days or More Past Due and Accruing	364	243
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	1,115,453	1,121,957
Total Past Due	2,880	3,370
Total loans	1,118,333	1,125,327
90 Days or More Past Due and Accruing	21	20
Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	8,120	9,195
Total Past Due	24,266	27,630
Total loans	32,386	36,825
TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	6,435	6,055
Total Past Due	423	516
Total loans	6,858	6,571
Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	14,555	15,250
Total Past Due	24,689	28,146
Total loans	39,244	43,396
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	13,562	10,034
30-59 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,654	2,135
30-59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	4,431	374
30-59 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	3,860	4,487
30-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,950	2,466
30-59 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	4,431	374
30-59 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	667	572
30-59 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,310	1,782
30-59 Days Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	230	348
30-59 Days Past Due [Member] | Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,540	2,130
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	3,461	5,469
60-89 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	682	683
60-89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	528	1,372
60-89 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,618	2,376
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	432	842
60-89 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due		172
60-89 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	528	1,200
60-89 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	201	196
60-89 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	754	2,033
60-89 Days Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	193	168
60-89 Days Past Due [Member] | Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	947	2,201
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	23,781	26,541
90 Days or More Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,917	3,794
90 Days or More Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	10,850	10,809
90 Days or More Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	7,340	8,198
90 Days or More Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	662	1,138
90 Days or More Past Due [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	970	236
90 Days or More Past Due [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	9,880	10,573
90 Days or More Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,012	2,602
90 Days or More Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	22,202	23,815
90 Days or More Past Due [Member] | Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	$ 22,202	$ 23,815

Loans and the Allowance for C48

Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Past due loans excluded TDRs past due and accruing	90 days

Loans and the Allowance for C49

Loans and the Allowance for Credit Losses - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	$ 44,762	$ 50,124
Total impaired loans, Unpaid principal balance	46,866	52,229
Recorded Investment, With no specific allowance recorded	37,140	41,291
Total impaired loans, Recorded investment	39,244	43,396
Unpaid Principal Balance, With a specific allowance recorded	2,104	2,105
Recorded Investment, With a specific allowance recorded	2,104	2,105
Related Allowance, With a specific allowance recorded	387	388
Average recorded investment, with no related specific allowance	39,217	37,415
Interest income recognized, With no related specific allowance	421	424
Average recorded investment, With a specific allowance recorded	2,105	5,562
Interest income recognized, With a specific allowance recorded	0	0
Total impaired loans, Average recorded investment	41,322	42,977
Total impaired loans, Interest income recognized	421	424
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	19,601	20,821
Recorded Investment, With no specific allowance recorded	17,751	18,982
Average recorded investment, with no related specific allowance	18,367	18,448
Interest income recognized, With no related specific allowance	66	69
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	918	1,084
Recorded Investment, With no specific allowance recorded	803	952
Average recorded investment, with no related specific allowance	878	761
Interest income recognized, With no related specific allowance	3	2
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	5,771	5,833
Recorded Investment, With no specific allowance recorded	4,971	5,169
Average recorded investment, with no related specific allowance	5,070	4,186
Interest income recognized, With no related specific allowance	5	5
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	873	412
Recorded Investment, With no specific allowance recorded	800	239
Average recorded investment, with no related specific allowance	520	588
Interest income recognized, With a specific allowance recorded	0	0
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	14,554	18,229
Recorded Investment, With no specific allowance recorded	10,319	12,863
Unpaid Principal Balance, With a specific allowance recorded	2,104	2,105
Recorded Investment, With a specific allowance recorded	2,104	2,105
Related Allowance, With a specific allowance recorded	387	388
Average recorded investment, with no related specific allowance	11,591	9,620
Interest income recognized, With no related specific allowance	345	346
Average recorded investment, With a specific allowance recorded	2,105	4,927
Interest income recognized, With a specific allowance recorded	0	0
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	3,045	3,745
Recorded Investment, With no specific allowance recorded	2,496	3,086
Average recorded investment, with no related specific allowance	2,791	3,812
Interest income recognized, With no related specific allowance	2	2
Average recorded investment, With a specific allowance recorded		635
Interest income recognized, With a specific allowance recorded	$ 0	$ 0

Loans and the Allowance for C50

Loans and the Allowance for Credit Losses - Recorded Investment in Non-Accrual Loans and TDRs (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Non-accrual loans	$ 32,386	$ 36,825
TDRs	9,255	9,436
Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	6,858	6,571
Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	2,397	2,865
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	800	239
TDRs	2	3
Commercial Real Estate - Land and Construction [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	2	3
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	10,821	13,318
TDRs	2,092	2,078
Commercial Real Estate - Improved Property [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	1,602	1,650
Commercial Real Estate - Improved Property [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	490	428
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	2,373	2,958
TDRs	217	225
Commercial and Industrial [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	123	128
Commercial and Industrial [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	94	97
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	4,540	4,762
TDRs	651	744
Home Equity [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	431	407
Home Equity [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	220	337
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	11,621	13,557
TDRs	2,094	2,081
Commercial Real Estate [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	1,602	1,650
Commercial Real Estate [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	492	431
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	13,149	14,661
TDRs	6,127	6,201
Residential Real Estate [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	4,602	4,321
Residential Real Estate [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	1,525	1,880
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	703	887
TDRs	166	185
Consumer [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	100	65
Consumer [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	$ 66	$ 120

Loans and the Allowance for C51

Loans and the Allowance for Credit Losses - Recorded Investment in Non-Accrual Loans and TDRs (Parenthetical) (Detail)	Mar. 31, 2018USD ($)Borrowers	Dec. 31, 2017USD ($)Borrowers
Receivables [Abstract]
Number of borrowers with loans greater than one million | Borrowers	2	3
Borrowers with large amount of loans outstanding, minimum amount of loans per borrower	$ 1,000,000	$ 1,000,000
Borrowers with large amount of loans outstanding, net	$ 5,600,000	$ 6,800,000

Loans and the Allowance for C52

Loans and the Allowance for Credit Losses - Loans Identified as TDRs (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)Contract	Mar. 31, 2017USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract	7	6
Pre-Modification Outstanding Recorded Investment	$ 207	$ 264
Post-Modification Outstanding Recorded Investment	$ 198	$ 195
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract		2
Pre-Modification Outstanding Recorded Investment		$ 126
Post-Modification Outstanding Recorded Investment		$ 122
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract	5	1
Pre-Modification Outstanding Recorded Investment	$ 203	$ 10
Post-Modification Outstanding Recorded Investment	$ 195	$ 9
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract	2	2
Pre-Modification Outstanding Recorded Investment	$ 4	$ 84
Post-Modification Outstanding Recorded Investment	$ 3	$ 21
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract		1
Pre-Modification Outstanding Recorded Investment		$ 44
Post-Modification Outstanding Recorded Investment		$ 43

Loans and the Allowance for C53

Loans and the Allowance for Credit Losses - TDRs Defaulted Later Restructured (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)Defaults	Mar. 31, 2017USD ($)Defaults
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults	2	1
Recorded Investment | $	$ 129	$ 9
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults	1
Recorded Investment | $	$ 122
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults		1
Recorded Investment | $		$ 9
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults	1
Recorded Investment | $	$ 7

Loans and the Allowance for C54

Loans and the Allowance for Credit Losses - Summary of Other Real Estate Owned and Repossessed Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Other real estate owned	$ 3,991	$ 5,195
Repossessed assets	76	102
Total other real estate owned and repossessed assets	$ 4,067	$ 5,297

Derivatives and Hedging Activ55

Derivatives and Hedging Activities - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018USD ($)Derivative	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)Derivative
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Aggregate notional amount	$ 309,200,000		$ 298,200,000
Net gain (loss) on change in fair value	336,000	$ 195,000
Collateral posted with market value on liability positions with credit risk-related contingent features	$ 2,900,000
Interest Rate Swaps [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps | Derivative	43		39
Net gain (loss) on change in fair value	$ 200,000	(200,000)
Income (loss) on derivative instrument not designated hedges	$ 400,000	$ 1,000,000

Derivatives and Hedging Activ56

Derivatives and Hedging Activities - Summary of Fair Values of Derivative Instruments on Balance Sheets (Detail) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	$ 309,200,000	$ 298,200,000
Asset Derivatives	9,404,000	7,400,000
Liability Derivatives	9,097,000	7,374,000
Interest Rate Swaps [Member] | Loan Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	309,242,000	298,223,000
Asset Derivatives	9,257,000	7,351,000
Liability Derivatives	9,083,000	7,345,000
Interest Rate Loan Commitments [Member] | Other Contract [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	24,730,000	20,319,000
Asset Derivatives	147,000	49,000
Best Efforts Forward Delivery Commitments [Member] | Other Contract [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	3,941,000	2,905,000
Liability Derivatives	11,000	6,000
Forward TBA Contracts [Member] | Other Contract [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	36,500,000	31,750,000
Liability Derivatives	$ 3,000	$ 23,000

Derivatives and Hedging Activ57

Derivatives and Hedging Activities - Summary of Effect of Derivative Instruments on Income Statement (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	$ 336	$ 195
Interest Rate Swaps [Member] | Other Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	(167)	$ 195
Interest Rate Loan Commitments [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	98
Best Efforts Forward Delivery Commitments [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	(5)
Forward TBA Contracts [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	$ 410

Pension Plan - Components of Ne

Pension Plan - Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost - benefits earned during year	$ 699	$ 636
Interest cost on projected benefit obligation	1,114	1,084
Expected return on plan assets	(2,204)	(1,886)
Amortization of prior service cost	6	6
Amortization of net loss	753	794
Net periodic pension cost	$ 368	$ 634

Pension Plan - Additional Infor

Pension Plan - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum required pension plan contribution	$ 5,100
Expected voluntary contribution for the year 2018	5,000
Available credit balance	56,900
Net periodic pension income	368	$ 634
Expected return on plan assets	2,204	1,886
Interest cost on projected benefit obligation	1,114	$ 1,084
Pentegra Defined Benefit Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Spinning off of asset cost	2,800
Net periodic pension income	62
Expected return on plan assets	200
Recognized net actuarial gain	3
Interest cost on projected benefit obligation	$ 100

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of Fair Value of Assets and Liabilities Measured on Recurring and Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 13,986	$ 13,457
Total debt securities - available-for-sale	1,728,377	1,261,865
Loans held for sale	12,962	20,320
Other real estate owned and repossessed assets	4,067	5,297
Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	13,986	13,457
Total debt securities - available-for-sale	1,728,377	1,261,865
Loans held for sale	12,962	20,320
Other assets - interest rate derivatives agreements	9,257	7,351
Total assets recurring fair value measurements	1,764,582	1,302,993
Nonrecurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities - interest rate derivatives agreements	9,083	7,345
Total liabilities recurring fair value measurements	9,083	7,345
Impaired loans	1,717	1,717
Other real estate owned and repossessed assets	4,067	5,297
Total assets recurring fair value measurements	5,784	7,014
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	9,894
US Treasury Securities [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	9,894
U.S. Government Sponsored Entities and Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	96,458	71,843
U.S. Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	96,458	71,843
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	1,344,410	934,922
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	1,344,410	934,922
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	140,926	114,867
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	140,926	114,867
Obligations of State and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	101,431	104,830
Obligations of State and Political Subdivisions [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	101,431	104,830
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	35,258	35,403
Corporate Debt Securities [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	35,258	35,403
Investments Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2,418	2,066
Investments Measured at Net Asset Value [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	2,418	2,066
Total assets recurring fair value measurements	2,418	2,066
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	11,568	11,391
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	11,568	11,391
Total assets recurring fair value measurements	11,568	11,391
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities - interest rate derivatives agreements	9,083	7,345
Total debt securities - available-for-sale	1,728,377	1,261,865
Loans held for sale	12,962	20,320
Other assets - interest rate derivatives agreements	9,257	7,351
Significant Other Observable Inputs (Level 2) [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	1,728,377	1,261,865
Loans held for sale	12,962	20,320
Other assets - interest rate derivatives agreements	9,257	7,351
Total assets recurring fair value measurements	1,750,596	1,289,536
Significant Other Observable Inputs (Level 2) [Member] | Nonrecurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other liabilities - interest rate derivatives agreements	9,083	7,345
Total liabilities recurring fair value measurements	9,083	7,345
Significant Other Observable Inputs (Level 2) [Member] | US Treasury Securities [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	9,894
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	96,458	71,843
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	1,344,410	934,922
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	140,926	114,867
Significant Other Observable Inputs (Level 2) [Member] | Obligations of State and Political Subdivisions [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	101,431	104,830
Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	35,258	35,403
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	1,717	1,717
Other real estate owned and repossessed assets	4,067	5,297
Total assets recurring fair value measurements	$ 5,784	$ 7,014

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair value transfer amount	$ 0	$ 0

Fair Value Measurement - Sche62

Fair Value Measurement - Schedule of Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Other real estate owned and repossessed assets	$ 4,067	$ 5,297
Impaired loans, Appraisal adjustments	(4.80%)	(4.80%)
Impaired loans, Liquidation expenses	(7.60%)	(7.60%)
Nonrecurring Fair Value Measurements [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	$ 1,717	$ 1,717
Other real estate owned and repossessed assets	4,067	5,297
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring Fair Value Measurements [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	1,717	1,717
Other real estate owned and repossessed assets	$ 4,067	$ 5,297
Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans, Appraisal adjustments	(4.80%)	(4.80%)
Impaired loans, Liquidation expenses	(7.60%)	(7.60%)

Fair Value Measurement - Estima

Fair Value Measurement - Estimates Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Financial Assets
Cash and due from banks	$ 100,845	$ 117,572	$ 115,084	$ 128,170
Equity securities	13,986	13,457
Debt securities available-for-sale	1,728,377	1,261,865
Debt securities held-to-maturity	1,006,042	1,009,500
Net loans	6,276,204	6,296,157
Loans held for sale	12,962	20,320
Accrued interest receivable	31,963	29,728
Financial Liabilities
Deposits	7,226,326	7,043,588
Federal Home Loan Bank borrowings	1,166,939	948,203
Other borrowings	207,653	184,805
Subordinated debt and junior subordinated debt	164,379	164,327
Accrued interest payable	4,033	3,178
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial Assets
Cash and due from banks	100,845	117,572
Equity securities	11,568	11,391
Accrued interest receivable	31,963	29,728
Financial Liabilities
Deposits	6,018,657	5,766,531
Other borrowings	205,651	182,785
Accrued interest payable	4,033	3,178
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets
Debt securities available-for-sale	1,728,377	1,261,865
Debt securities held-to-maturity	1,004,912	1,023,191
Loans held for sale	12,962	20,320
Other assets - interest rate derivatives	9,257	7,351
Financial Liabilities
Deposits	1,211,678	1,287,005
Federal Home Loan Bank borrowings	1,161,442	944,706
Other borrowings	1,976	2,029
Subordinated debt and junior subordinated debt	149,887	146,484
Other liabilities - interest rate derivatives	9,083	7,345
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets
Debt securities held-to-maturity	590	593
Net loans	6,158,399	6,212,823
Carrying Amount [Member]
Financial Assets
Cash and due from banks	100,845	117,572
Equity securities	13,986	13,457
Debt securities available-for-sale	1,728,377	1,261,865
Debt securities held-to-maturity	1,006,042	1,009,500
Net loans	6,276,204	6,296,157
Loans held for sale	12,962	20,320
Other assets - interest rate derivatives	9,257	7,351
Accrued interest receivable	31,963	29,728
Financial Liabilities
Deposits	7,226,326	7,043,588
Federal Home Loan Bank borrowings	1,166,939	948,203
Other borrowings	207,653	184,805
Subordinated debt and junior subordinated debt	164,379	164,327
Other liabilities - interest rate derivatives	9,083	7,345
Accrued interest payable	4,033	3,178
Fair Value Estimate [Member]
Financial Assets
Cash and due from banks	100,845	117,572
Equity securities	13,986	13,457
Debt securities available-for-sale	1,728,377	1,261,865
Debt securities held-to-maturity	1,005,502	1,023,784
Net loans	6,158,399	6,212,823
Loans held for sale	12,962	20,320
Other assets - interest rate derivatives	9,257	7,351
Accrued interest receivable	31,963	29,728
Financial Liabilities
Deposits	7,230,335	7,053,536
Federal Home Loan Bank borrowings	1,161,442	944,706
Other borrowings	207,627	184,814
Subordinated debt and junior subordinated debt	149,887	146,484
Other liabilities - interest rate derivatives	9,083	7,345
Accrued interest payable	4,033	3,178
Investments Measured at Net Asset Value [Member]
Financial Assets
Equity securities	$ 2,418	$ 2,066

Revenue Recognition - Summary o

Revenue Recognition - Summary of Revenue Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule Of Revenue Recognition [Line Items]
Total trust fees	$ 6,503	$ 6,143
Service charges on deposits	4,822	4,853
Total net securities brokerage revenue	1,670	1,762
Electronic banking fees	4,829	4,528
Mortgage banking income	1,004	1,440
Gain/loss on sale of OREO/other assets	$ 262	$ (76)
Trust Account Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	Over time
Total trust fees	$ 4,292
WesMark Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	Over time
Total trust fees	$ 2,211
Commercial Banking Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	Over time
Service charges on deposits	$ 407
Personal Service Charges [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	At a point in time & Over time
Service charges on deposits	$ 4,415
Annuity Commissions [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	At a point in time
Total net securities brokerage revenue	$ 1,200
Equity and Debt Security Trades [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	At a point in time
Total net securities brokerage revenue	$ 102
Managed Money [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	Over time
Total net securities brokerage revenue	$ 141
Trail Commissions [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	Over time
Total net securities brokerage revenue	$ 227
Electronic Banking Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	At a point in time
Mortgage [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	At a point in time
OREO/other assets [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition	At a point in time

Comprehensive Income_(Loss) - C

Comprehensive Income/(Loss) - Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 1,395,321	$ 1,341,408
Amounts reclassified from accumulated other comprehensive income	387	605
Total other comprehensive income	(14,518)	2,285
Ending Balance	1,403,026	1,359,153
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(18,626)	(17,758)
Amounts reclassified from accumulated other comprehensive income	437	655
Total other comprehensive income	437	655
Ending Balance	(18,189)	(17,103)
Accumulated Unrealized Gains (Losses) on Debt Securities Available for Sale [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(13,250)	(9,890)
Other comprehensive income before reclassifications	(14,905)	1,680
Total other comprehensive income	(14,905)	1,680
Adoption of Accounting Standard ASU 2016-01	(1,063)
Ending Balance	(29,218)	(8,210)
Accumulated Unrealized Gains on Debt Securities Transferred from Available For Sale to Held to Maturity [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	381	522
Amounts reclassified from accumulated other comprehensive income	(50)	(50)
Total other comprehensive income	(50)	(50)
Ending Balance	331	472
Accumulated Other Comprehensive (Loss) Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(31,495)	(27,126)
Other comprehensive income before reclassifications	(14,905)	1,680
Amounts reclassified from accumulated other comprehensive income	387	605
Total other comprehensive income	(14,518)	2,285
Adoption of Accounting Standard ASU 2016-01	(1,063)
Ending Balance	$ (47,076)	$ (24,841)

Comprehensive Income_(Loss) -66

Comprehensive Income/(Loss) - Components of Accumulated Other Comprehensive Income (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Percentage of Federal and State income tax rate	23.00%	37.00%

Comprehensive Income_(Loss) - S

Comprehensive Income/(Loss) - Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains (Non-interest income)	$ 39	$ (12)
Interest and dividends on securities (Interest and dividend income)	(16,377)	(14,487)
Employee benefits (Non-interest expense)	6,912	8,210
Provision for income taxes	7,004	10,622
Net effect on accumulated other comprehensive income for the period	387	605
Accumulated Unrealized Gains on Debt Securities Transferred from Available For Sale to Held to Maturity [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net effect on accumulated other comprehensive income for the period	(50)	(50)
Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net effect on accumulated other comprehensive income for the period	437	655
Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Unrealized Gains (Losses) on Debt Securities Available for Sale [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains (Non-interest income)	0	0
Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Unrealized Gains on Debt Securities Transferred from Available For Sale to Held to Maturity [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and dividends on securities (Interest and dividend income)	(66)	(72)
Provision for income taxes	16	22
Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Employee benefits (Non-interest expense)	756	801
Provision for income taxes	$ (319)	$ (146)

Commitments and Contingent Li68

Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Allowance for credit losses associated with loan commitments	$ 629	$ 574	$ 548	$ 571
Liability associated with letters of credit	$ 200	$ 200

Commitments and Contingent Li69

Commitments and Contingent Liabilities - Commitments to Extend Credit, Guarantees and Various Letters of Credit Outstanding (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Lines of credit	$ 1,464,970	$ 1,452,697
Loans approved but not closed	358,367	245,644
Overdraft limits	124,752	126,671
Letters of credit	31,947	31,951
Contingent obligations and other guarantees	$ 6,796	$ 6,700

Business Segments - Additional

Business Segments - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)Segment	Mar. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Operating segments | Segment	2
Trust and Investment Services [Member]
Segment Reporting Information [Line Items]
Market value of assets managed or held in custody by trust and investment services segment	$ 4,000	$ 3,800
Total non-fiduciary assets of the trust and investment services segment	$ 1.8	$ 3.8

Business Segments - Financial I

Business Segments - Financial Information by Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Interest and dividend income	$ 86,417	$ 79,924
Interest expense	13,125	9,205
Net interest income	73,292	70,719
Provision for credit losses	2,168	2,711
Net interest income after provision for credit losses	71,124	68,008
Non-interest income	23,980	22,884
Non-interest expense	54,571	54,384
Income before provision for income taxes	40,533	36,508
Provision for income taxes	7,004	10,622
Net income	33,529	25,886
Community Banking [Member]
Segment Reporting Information [Line Items]
Interest and dividend income	86,417	79,924
Interest expense	13,125	9,205
Net interest income	73,292	70,719
Provision for credit losses	2,168	2,711
Net interest income after provision for credit losses	71,124	68,008
Non-interest income	17,477	16,741
Non-interest expense	50,894	50,992
Income before provision for income taxes	37,707	33,757
Provision for income taxes	6,411	9,522
Net income	31,296	24,235
Trust and Investment Services [Member]
Segment Reporting Information [Line Items]
Non-interest income	6,503	6,143
Non-interest expense	3,677	3,392
Income before provision for income taxes	2,826	2,751
Provision for income taxes	593	1,100
Net income	$ 2,233	$ 1,651

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Thousands	Apr. 19, 2018USD ($)Branch$ / sharesshares	Apr. 05, 2018USD ($)shares	Mar. 31, 2018USD ($)Branches	Dec. 31, 2017USD ($)
Subsequent Event [Line Items]
Total Assets			$ 10,245,419	$ 9,816,178
Deposits			7,226,326	7,043,588
Portfolio loans, net of unearned income			6,322,538	$ 6,341,441
First Sentry Bancshares, Inc. [Member]
Subsequent Event [Line Items]
Total Assets			705,100
Deposits			577,400
Portfolio loans, net of unearned income			$ 459,500
Number of branches | Branches			5
First Sentry Bancshares, Inc. [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Value of acquisition		$ 107,500
Number of shares issued for acquisition | shares		2,500,000
Cash paid for acquisition		$ 1,000
Merger related expenses		$ 200
Farmers Capital Bank Corporation [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Deposits	$ 1,400,000
Portfolio loans, net of unearned income	1,000,000
Value of acquisition	378,200
Total assets acquired	$ 1,700,000
Number of branches entered into definitive agreement and plan of merger | Branch	34
Number of shares issued for each acquiree share | shares	1.053
Cash paid in excess of shares issued | $ / shares	$ 5
Total consideration per share | $ / shares	$ 50.31