WesBanco (WSBC) 10-Q 2 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 22, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	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 Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		54,598,186

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks, including interest bearing amounts of $88,854 and $19,826, respectively	$ 273,680	$ 117,572
Securities:
Equity securities, at fair value	12,784	13,457
Available-for-sale debt securities, at fair value	2,008,232	1,261,865
Held-to-maturity debt securities (fair values of $1,014,361 and $1,023,784, respectively)	1,025,538	1,009,500
Total securities	3,046,554	2,284,822
Loans held for sale	55,913	20,320
Portfolio loans, net of unearned income	7,726,423	6,341,441
Allowance for loan losses	(48,902)	(45,284)
Net portfolio loans	7,677,521	6,296,157
Premises and equipment, net	159,284	130,722
Accrued interest receivable	39,465	29,728
Goodwill and other intangible assets, net	928,083	589,264
Bank-owned life insurance	223,995	192,589
Other assets	194,984	155,004
Total Assets	12,599,479	9,816,178
Deposits:
Non-interest bearing demand	2,411,862	1,846,748
Interest bearing demand	2,187,662	1,625,015
Money market	1,178,950	1,024,856
Savings deposits	1,649,684	1,269,912
Certificates of deposit	1,513,600	1,277,057
Total deposits	8,941,758	7,043,588
Federal Home Loan Bank borrowings	1,131,253	948,203
Other short-term borrowings	294,281	184,805
Subordinated debt and junior subordinated debt	189,745	164,327
Total borrowings	1,615,279	1,297,335
Accrued interest payable	6,623	3,178
Other liabilities	108,550	76,756
Total Liabilities	10,672,210	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; 54,604,294 and 44,043,244 shares issued, respectively; 54,603,967 and 44,043,244 shares outstanding, respectively	113,758	91,756
Capital surplus	1,165,006	684,730
Retained earnings	709,477	651,357
Treasury stock (327 and 0 shares-at cost, respectively)	(15)
Accumulated other comprehensive loss	(59,873)	(31,495)
Deferred benefits for directors	(1,084)	(1,027)
Total Shareholders' Equity	1,927,269	1,395,321
Total Liabilities and Shareholders' Equity	$ 12,599,479	$ 9,816,178

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Interest bearing deposits, banks	$ 88,854	$ 19,826
Held-to-maturity securities, fair values	$ 1,014,361	$ 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	54,604,294	44,043,244
Common stock, shares outstanding	54,603,967	44,043,244
Treasury stock, shares	327	0

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
INTEREST AND DIVIDEND INCOME
Loans, including fees	$ 86,605	$ 70,342	$ 234,276	$ 202,600
Interest and dividends on securities:
Taxable	14,964	9,711	40,702	28,682
Tax-exempt	5,326	4,862	15,216	14,617
Total interest and dividends on securities	20,290	14,573	55,918	43,299
Other interest income	1,498	574	3,402	1,674
Total interest and dividend income	108,393	85,489	293,596	247,573
INTEREST EXPENSE
Interest bearing demand deposits	3,501	1,814	9,174	4,413
Money market deposits	1,360	751	3,332	1,970
Savings deposits	352	189	768	555
Certificates of deposit	3,276	2,610	8,789	7,512
Total interest expense on deposits	8,489	5,364	22,063	14,450
Federal Home Loan Bank borrowings	6,691	3,628	17,142	9,608
Other short-term borrowings	965	394	2,497	954
Subordinated debt and junior subordinated debt	2,315	1,849	6,425	5,449
Total interest expense	18,460	11,235	48,127	30,461
NET INTEREST INCOME	89,933	74,254	245,469	217,112
Provision for credit losses	1,035	2,516	4,911	7,610
Net interest income after provision for credit losses	88,898	71,738	240,558	209,502
NON-INTEREST INCOME
Electronic banking fees	6,139	4,883	16,697	14,395
Net securities brokerage revenue	1,836	1,721	5,315	5,164
Bank-owned life insurance	1,232	1,164	5,116	3,671
Mortgage banking income	1,521	1,103	4,297	3,511
Net securities gains	84	6	403	511
Net gain/(loss) on other real estate owned and other assets	150	(298)	641	9
Other income	2,684	1,642	6,444	6,318
Total non-interest income	26,224	20,899	73,715	65,906
NON-INTEREST EXPENSE
Salaries and wages	30,335	24,957	82,213	71,575
Employee benefits	7,905	7,728	22,782	23,670
Net occupancy	4,957	4,132	13,715	12,969
Equipment	4,488	3,905	12,532	12,043
Marketing	1,446	1,599	3,967	4,482
FDIC insurance	789	945	2,315	2,677
Amortization of intangible assets	1,821	1,223	4,218	3,736
Restructuring and merger-related expense	10,811		16,468	491
Other operating expenses	13,568	11,265	36,024	34,380
Total non-interest expense	76,120	55,754	194,234	166,023
Income before provision for income taxes	39,002	36,883	120,039	109,385
Provision for income taxes	6,516	10,527	20,855	30,801
NET INCOME	$ 32,486	$ 26,356	$ 99,184	$ 78,584
EARNINGS PER COMMON SHARE
Basic	$ 0.65	$ 0.60	$ 2.11	$ 1.79
Diluted	$ 0.64	$ 0.60	$ 2.11	$ 1.78
AVERAGE COMMON SHARES OUTSTANDING
Basic	50,277,847	44,031,813	46,965,095	43,992,017
Diluted	50,432,112	44,086,881	47,107,829	44,059,469
DIVIDENDS DECLARED PER COMMON SHARE	$ 0.29	$ 0.26	$ 0.87	$ 0.78
COMPREHENSIVE INCOME	$ 25,965	$ 27,637	$ 71,869	$ 84,873
Total Trust Fees [Member]
NON-INTEREST INCOME
NON-INTEREST INCOME	6,265	5,358	18,520	17,073
Service Charges on Deposits [Member]
NON-INTEREST INCOME
NON-INTEREST INCOME	$ 6,313	$ 5,320	$ 16,282	$ 15,254

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	First Sentry Bancshares, Inc. [Member]	Farmers Capital Bank Corporation [Member]	Common Stock [Member]	Common Stock [Member]First Sentry Bancshares, Inc. [Member]	Common Stock [Member]Farmers Capital Bank Corporation [Member]	Capital Surplus [Member]	Capital Surplus [Member]First Sentry Bancshares, Inc. [Member]	Capital Surplus [Member]Farmers Capital Bank Corporation [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Treasury Stock [Member]Farmers Capital Bank Corporation [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	78,584									78,584
Other comprehensive income	6,289												6,289
Comprehensive income	84,873
Common dividends declared	(34,326)									(34,326)
Treasury shares acquired	(488)										$ (488)
Treasury shares acquired, shares				(12,987)
Stock options exercised	1,121			$ 75			858				188
Stock options exercised, shares				40,834
Restricted stock granted				$ 154			(154)
Restricted stock granted, shares				74,023
Stock compensation expense	1,970						1,970
Deferred benefits for directors- net							167							(167)
Ending Balance at Sep. 30, 2017	1,394,558			$ 91,753			683,348			641,329	(300)		(20,837)	(735)
Ending Balance, shares at Sep. 30, 2017				44,033,585
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	99,184									99,184
Other comprehensive income	(27,315)												(27,315)
Comprehensive income	71,869
Common dividends declared	(42,127)									(42,127)
Adoption of accounting standard ASU 2016-01										1,063			(1,063)
Shares issued for acquisition		$ 107,347	$ 391,267		$ 5,206	$ 16,487		$ 102,141	$ 374,464			$ 316
Shares issued for acquisition, shares					2,498,761	7,920,387
Treasury shares acquired	(696)						34				(730)
Treasury shares acquired, shares				(15,489)
Stock options exercised	1,849			$ 104			1,346				399
Stock options exercised, shares				58,763
Restricted stock granted				$ 205			(205)
Restricted stock granted, shares				98,301
Stock compensation expense	2,933						2,933
Deferred benefits for directors- net	(494)						(437)							(57)
Ending Balance at Sep. 30, 2018	$ 1,927,269			$ 113,758			$ 1,165,006			$ 709,477	$ (15)		$ (59,873)	$ (1,084)
Ending Balance, shares at Sep. 30, 2018				54,603,967

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Common dividends declared, per share	$ 0.29	$ 0.26	$ 0.87	$ 0.78

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 122,444	$ 93,506
INVESTING ACTIVITIES
Net decrease (increase) in loans held for investment	52,411	(122,332)
Debt securities available-for-sale:
Proceeds from sales	82,134	7,760
Proceeds from maturities, prepayments and calls	188,020	156,944
Purchases of securities	(688,020)	(225,404)
Debt securities held-to-maturity:
Proceeds from maturities, prepayments and calls	51,973	90,457
Purchases of securities	(66,058)	(53,251)
Equity securities:
Proceeds from sales	1,511
Purchases of securities	(431)
Proceeds from bank-owned life insurance	4,772	349
Purchases of premises and equipment - net	(2,400)	(6,223)
Net cash received from acquisitions	278,654
Sale of portfolio loans-net	12,996
Net cash used in investing activities	(84,438)	(151,700)
FINANCING ACTIVITIES
(Decrease) increase in deposits	(20,443)	61,389
Proceeds from Federal Home Loan Bank borrowings	575,000	560,000
Repayment of Federal Home Loan Bank borrowings	(447,381)	(513,911)
Increase in other short-term borrowings	90,043	20,200
Decrease in federal funds purchased	(25,000)	(54,000)
Repayment of junior subordinated debt	(17,519)
Dividends paid to common shareholders	(37,751)	(33,416)
Issuance of common stock	1,578	991
Treasury shares purchased-net	(425)	(358)
Net cash provided by financing activities	118,102	40,895
Net increase (decrease) in cash and cash equivalents	156,108	(17,299)
Cash and cash equivalents at beginning of the period	117,572	128,170
Cash and cash equivalents at end of the period	273,680	110,871
SUPPLEMENTAL DISCLOSURES
Interest paid on deposits and other borrowings	46,524	29,857
Income taxes paid	13,050	20,825
Transfers of loans to other real estate owned	393	$ 506
Transfers of loans to held for sale	12,996
First Sentry Bancshares, Inc. [Member]
SUPPLEMENTAL DISCLOSURES
Non-cash transactions related to acquisition	107,347
Farmers Capital Bank Corporation [Member]
SUPPLEMENTAL DISCLOSURES
Non-cash transactions related to acquisition	$ 391,267

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES 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 — 2018-15, Other—Internal-Use 350-40): internal-use internal-use 2018-15 In August 2018, the FASB issued ASU 2018-14, 715-20): 715-20 2018-14 In August 2018, the FASB issued ASU 2018-13, 2018-13 In August 2017, the FASB issued ASU 2017-12, 2017-12 In March 2017, the FASB issued ASU 2017-07 non-interest In January 2017, the FASB issued ASU 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 September 2016, the FASB issued ASU 2016-13 held-to-maturity available-for-sale In February 2016, the FASB issued ASU 2016-02 2018-01, 2018-10, 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,

Mergers and Acquisitions

Mergers and Acquisitions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Mergers and Acquisitions	NOTE 2. MERGERS AND ACQUISITIONS First Sentry Bancshares, Inc. (“FTSB”) On April 5, 2018, WesBanco completed its acquisition of FTSB, a bank holding company headquartered in Huntington, WV. On the acquisition date, FTSB had approximately $705.6 million in assets, excluding goodwill, which included approximately $448.1 million in loans and $142.9 million in securities. The FTSB acquisition was valued at $108.3 million, based on WesBanco’s closing stock price on April 5, 2018, of $42.96, and resulted in WesBanco issuing 2,498,761 shares of its common stock and $1.0 million in cash in exchange for all of the outstanding shares of FTSB common stock including stock options. The assets and liabilities of FTSB were 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 have been included in WesBanco’s Consolidated Statements of Income since that date. The fair values for certain assets and liabilities acquired from FTSB on April 5, 2018 represent preliminary estimates. Based on a preliminary purchase price allocation, WesBanco recorded $66.8 million in goodwill and $8.1 million in core deposit intangibles in its Community Banking segment. None of the goodwill is deductible for income tax purposes, as the acquisition is accounted for as a tax-free For the nine months ended September 30, 2018, WesBanco recorded merger-related expenses of $5.5 million associated with the FTSB acquisition. The preliminary purchase price of the FTSB acquisition and resulting goodwill is summarized as follows: (unaudited, in thousands) April 5, 2018 Purchase Price: Fair value of WesBanco shares issued $ 107,347 Cash consideration for outstanding FTSB shares 975 Total purchase price $ 108,322 Fair value of: Tangible assets acquired $ 610,443 Core deposit and other intangible assets acquired 8,078 Liabilities assumed (664,172 ) Net cash received in the acquisition 87,124 Fair value of net assets acquired 41,473 Goodwill recognized $ 66,849 The following table presents the preliminary allocation of the purchase price of the assets acquired and the liabilities assumed at the date of acquisition, as WesBanco intends to finalize its accounting for the acquisition of FTSB within one year from the date of acquisition: (unaudited, in thousands) April 5, 2018 Assets acquired Cash and due from banks $ 87,124 Securities 142,903 Loans 448,075 Goodwill and other intangible assets 74,927 Accrued income and other assets 19,465 Total assets acquired $ 772,494 Liabilities assumed Deposits $ 590,065 Borrowings 70,710 Accrued expenses and other liabilities 3,397 Total liabilities assumed $ 664,172 Net assets acquired $ 108,322 The following table presents the changes in the allocation of the purchase price of the assets acquired and the liabilities assumed at the date of the acquisition previously reported as of June 30, 2018: (unaudited, in thousands) April 5, 2018 Goodwill recognized as of June 30, 2018 $ 66,219 Change in fair value of net assets acquired: Assets Loans (264 ) Other intangible assets (159 ) Accrued income and other assets (6 ) Liabilities Deposits (47 ) Accrued expenses and other liabilities (154 ) Fair value of net assets acquired $ (630 ) Increase in goodwill recognized 630 Goodwill recognized as of September 30, 2018 $ 66,849 The fair value estimates for loans, deferred taxes and other liabilities have continued to fluctuate as the final valuations and/or appraisals are completed. The Company expects to finalize the purchase price accounts of FTSB within one year of the date of acquisition. Farmers Capital Bank Corporation (“FFKT”) On August 20, 2018, WesBanco completed its acquisition of FFKT, a bank holding company headquartered in Frankfort, KY. On the acquisition date, FFKT had approximately $1.6 billion in assets, excluding goodwill, which included approximately $1.0 billion in loans and $239.3 million in securities. The FFKT acquisition was valued at $428.9 million, based on WesBanco’s closing stock price on August 20, 2018, of $49.40, and resulted in WesBanco issuing 7,920,387 shares of its common stock and $37.6 million in cash in exchange for all of the outstanding shares of FFKT common stock. The assets and liabilities of FFKT were recorded on WesBanco’s Balance Sheet at their preliminary estimated fair values as of August 20, 2018, the acquisition date, and FFKT’s results of operations have been included in WesBanco’s Consolidated Statements of Income since that date. Due to the timing of the acquisition relative to the end of the reporting period, the fair values for certain assets and liabilities acquired from FFKT on August 20, 2018 represent preliminary estimates. Based on a preliminary purchase price allocation, WesBanco recorded $225.1 million in goodwill and $39.7 million in core deposit intangibles in its community banking segment and $2.9 million in trust customer relationship intangibles in its trust and investment services segment. None of the goodwill is deductible for income tax purposes, as the acquisition is accounted for as a tax-free For the nine months ended September 30, 2018, WesBanco recorded merger-related expenses of $11.0 million associated with the FFKT acquisition. The preliminary purchase price of the FFKT acquisition and resulting goodwill is summarized as follows: (unaudited, in thousands) August 20, 2018 Purchase Price: Fair value of WesBanco shares issued $ 391,267 Cash consideration for outstanding FFKT shares 37,634 Total purchase price $ 428,901 Fair value of: Tangible assets acquired $ 1,360,951 Core deposit and other intangible assets acquired 42,593 Liabilities assumed (1,429,874 ) Net cash received in the acquisition 230,139 Fair value of net assets acquired 203,809 Goodwill recognized $ 225,092 The following table presents the preliminary allocation of the purchase price of the assets acquired and the liabilities assumed at the date of acquisition, as WesBanco intends to finalize its accounting for the acquisition of FFKT within one year from the date of acquisition: (unaudited, in thousands) August 20, 2018 Assets acquired Cash and due from banks $ 230,139 Securities 239,321 Loans 1,028,120 Goodwill and other intangible assets 267,685 Accrued income and other assets 93,510 Total assets acquired $ 1,858,775 Liabilities assumed Deposits $ 1,330,328 Borrowings 71,780 Accrued expenses and other liabilities 27,766 Total liabilities assumed $ 1,429,874 Net assets acquired $ 428,901

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	NOTE 3. EARNINGS PER COMMON SHARE Earnings per common share are calculated as follows: For the Three Months Ended For the Nine Months Ended (unaudited, in thousands, except shares and per share amounts) 2018 2017 2018 2017 Numerator for both basic and diluted earnings per common share: Net income $ 32,486 $ 26,356 $ 99,184 $ 78,584 Denominator: Total average basic common shares outstanding 50,277,847 44,031,813 46,965,095 43,992,017 Effect of dilutive stock options and other stock compensation 154,265 55,068 142,734 67,452 Total diluted average common shares outstanding 50,432,112 44,086,881 47,107,829 44,059,469 Earnings per common share—basic $ 0.65 $ 0.60 $ 2.11 $ 1.79 Earnings per common share—diluted $ 0.64 $ 0.60 $ 2.11 $ 1.78 All options to purchase shares were included in the computation of net income per diluted share for the three months ended September 30, 2018 while 117,550 shares were not included in the computation of net income per diluted share for the three months ended September 30, 2017 because the exercise price was greater than the average market price of the common shares and, therefore, the effect would be antidilutive. Options to purchase 117,600 shares at September 30, 2018 were not included in the computation of net income per diluted share for the nine months ended September 30, 2018 because the exercise price was greater than the average market price of the common shares, and therefore, the effect would be antidilutive. All stock options were included in the computation of net income per diluted share for the nine months ended September 30, 2017. As of September 30, 2018, contingently issuable shares totaling 45,840, were estimated to be awarded under the 2018 and 2017 total shareholder return plans as stock performance targets have been met to date and are included in the diluted calculation. As of September 30, 2018, the shares related to the 2016 total shareholder return plan were not included in the calculation because the effect would be antidilutive. Performance-based restricted stock compensation totaling 17,081 shares were estimated to be awarded as of September 30, 2018 and are included in the diluted calculation for both the three months and nine months ended September 30, 2018. As of September 30, 2017, the shares related to the 2017 and 2016 total shareholder return plan were not included in the calculation because the effect would be antidilutive. Performance-based restricted stock compensation totaling 4,502 shares were estimated to be awarded as of September 30, 2017, and are included in the diluted calculation for both the three months and nine months ended September 30, 2017. On April 5, 2018, WesBanco issued 2,498,761 shares of common stock to complete its acquisition of FTSB and granted 9,465 shares of restricted stock to certain FTSB employees. These shares are included in average shares outstanding beginning on that date. For additional information relating to the FTSB acquisition, refer to Note 2, “Mergers and Acquisitions.” On August 20, 2018, WesBanco issued 7,920,387 shares of common stock, 6,690 of which were treasury stock, to complete its acquisition of FFKT and granted 18,685 shares of restricted stock to certain FFKT employees. These shares are included in average shares outstanding beginning on that date. For additional information relating to the FFKT acquisition, refer to Note 2, “Mergers and Acquisitions.”

Securities

Securities	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	NOTE 4. SECURITIES The following table presents the fair value and amortized cost of available-for-sale held-to-maturity September 30, 2018 December 31, 2017 (unaudited, in thousands) Amortized Cost Gross Gross Estimated Amortized Gross Gross Estimated Available-for-sale U.S. Treasury $ 9,952 $ — $ (15 ) $ 9,937 $ — $ — $ — $ — U.S. Government sponsored entities and agencies 154,054 17 (4,122 ) 149,949 72,425 24 (606 ) 71,843 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 1,500,563 44 (50,853 ) 1,449,754 954,115 214 (19,407 ) 934,922 Commerical mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 174,331 15 (5,585 ) 168,761 116,448 4 (1,585 ) 114,867 Obligations of states and political subdivisions 187,501 1,445 (2,295 ) 186,651 102,363 2,927 (460 ) 104,830 Corporate debt securities 43,259 160 (239 ) 43,180 35,234 228 (59 ) 35,403 Total available-for-sale $ 2,069,660 $ 1,681 $ (63,109 ) $ 2,008,232 $ 1,280,585 $ 3,397 $ (22,117 ) $ 1,261,865 Held-to-maturity U.S. Government sponsored entities and agencies $ 11,699 $ — $ (615 ) $ 11,084 $ 11,465 $ — $ (325 ) $ 11,140 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 154,018 103 (6,788 ) 147,333 170,025 544 (2,609 ) 167,960 Obligations of states and political subdivisions 826,514 6,434 (9,743 ) 823,205 794,655 17,364 (1,609 ) 810,410 Corporate debt securities 33,307 5 (573 ) 32,739 33,355 919 — 34,274 Total held-to-maturity $ 1,025,538 $ 6,542 $ (17,719 ) $ 1,014,361 $ 1,009,500 $ 18,827 $ (4,543 ) $ 1,023,784 Total debt securities $ 3,095,198 $ 8,223 $ (80,828 ) $ 3,022,593 $ 2,290,085 $ 22,224 $ (26,660 ) $ 2,285,649 At September 30, 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 $8.5 million 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 $12.8 million and $13.5 million at September 30, 2018 and December 31, 2017, respectively. The following table presents the fair value of available-for-sale held-to-maturity September 30, 2018 (unaudited, in thousands) One Year One to Five to After Mortgage-backed Total Available-for-sale U.S. Treasury $ 9,937 $ — $ — $ — $ — $ 9,937 U.S. Government sponsored entities and agencies 10,479 6,260 17,881 15,298 100,031 149,949 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 1,449,754 1,449,754 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 168,761 168,761 Obligations of states and political subdivisions 9,288 48,959 76,972 51,432 — 186,651 Corporate debt securities 8,014 33,251 1,915 — — 43,180 Total available-for-sale $ 37,718 $ 88,470 $ 96,768 $ 66,730 $ 1,718,546 $ 2,008,232 Held-to-maturity U.S. Government sponsored entities and agencies $ — $ — $ — $ — $ 11,084 $ 11,084 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 147,333 147,333 Obligations of states and political subdivisions 6,149 138,709 387,775 290,572 — 823,205 Corporate debt securities — 7,449 25,290 — — 32,739 Total held-to-maturity $ 6,149 $ 146,158 $ 413,065 $ 290,572 $ 158,417 $ 1,014,361 Total debt securities $ 43,867 $ 234,628 $ 509,833 $ 357,302 $ 1,876,963 $ 3,022,593 (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 $1.9 billion and $1.4 billion at September 30, 2018 and December 31, 2017, respectively, were pledged as security for public and trust funds, and securities sold under agreements to repurchase. Proceeds from the sale 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 For the Nine Months Ended (unaudited, in thousands) 2018 2017 2018 2017 Debt securities: Gross realized gains $ 88 $ 29 $ 100 $ 603 Gross realized losses (13 ) (23 ) (31 ) (92 ) Net gains on debt securities $ 75 $ 6 $ 69 $ 511 Equity securities: Unrealized gains recognized on securities still held $ 11 $ — $ 330 $ — Net realized (losses) gains recognized on securities sold (2 ) — 4 — Net gains on equity securities $ 9 $ — $ 334 $ — Net securities gains $ 84 $ 6 $ 403 $ 511 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 September 30, 2018 and December 31, 2017: September 30, 2018 Less than 12 months 12 months or more Total (unaudited, dollars in thousands) Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of U.S. Treasury $ 9,937 $ (15 ) 1 $ — $ — — $ 9,937 $ (15 ) 1 U.S. Government sponsored entities and agencies 93,881 (2,264 ) 38 60,410 (2,473 ) 11 154,291 (4,737 ) 49 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 759,415 (13,670 ) 188 822,774 (43,971 ) 260 1,582,189 (57,641 ) 448 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 79,056 (1,239 ) 15 86,703 (4,346 ) 11 165,759 (5,585 ) 26 Obligations of states and political subdivisions 493,252 (7,866 ) 855 120,843 (4,172 ) 236 614,095 (12,038 ) 1091 Corporate debt securities 42,816 (738 ) 17 1,915 (74 ) 1 44,731 (812 ) 18 Total temporarily impaired securities $ 1,478,357 $ (25,792 ) 1,114 $ 1,092,645 $ (55,036 ) 519 $ 2,571,002 $ (80,828 ) 1,633 December 31, 2017 Less than 12 months 12 months or more Total (unaudited, dollars in thousands) Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of 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 $53.8 million and $45.9 million at September 30, 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	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans and the Allowance for Credit Losses	NOTE 5. 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 $2.8 million and $1.6 million at September 30, 2018 and December 31, 2017, respectively. The unamortized discount on purchased portfolio loans from acquisitions was $54.3 million, including $6.7 million related to FTSB and $25.9 million related to FFKT, and $21.9 million at September 30, 2018 and December 31, 2017, respectively. (unaudited, in thousands) September 30, December 31, Commercial real estate: Land and construction $ 538,922 $ 392,597 Improved property 3,367,299 2,601,851 Total commercial real estate 3,906,221 2,994,448 Commercial and industrial 1,292,073 1,125,327 Residential real estate 1,598,477 1,353,301 Home equity 604,106 529,196 Consumer 325,546 339,169 Total portfolio loans 7,726,423 6,341,441 Loans held for sale 55,913 20,320 Total loans $ 7,782,336 $ 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 Nine Months Ended September 30, 2018 and 2017 (unaudited, in thousands) Commercial Commercial Real Estate - Commercial Residential Home Consumer Deposit 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 789 (721 ) 2,538 1,106 (292 ) 541 840 4,801 Provision for loan commitments 67 (3 ) 32 2 9 3 — 110 Total provision for credit losses 856 (724 ) 2,570 1,108 (283 ) 544 840 4,911 Charge-offs (137 ) (719 ) (871 ) (873 ) (745 ) (2,465 ) (941 ) (6,751 ) Recoveries 400 1,098 970 336 830 1,657 277 5,568 Net charge-offs 263 379 99 (537 ) 85 (808 ) (664 ) (1,183 ) Balance at September 30, 2018: Allowance for loan losses 4,169 20,824 12,051 3,775 4,290 2,796 997 48,902 Allowance for loan commitments 186 23 205 9 221 40 — 684 Total ending allowance for credit losses $ 4,355 $ 20,847 $ 12,256 $ 3,784 $ 4,511 $ 2,836 $ 997 $ 49,586 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 415 1,619 2,842 (203 ) 1,259 922 680 7,534 Provision for loan commitments (18 ) 4 45 — 49 (4 ) — 76 Total provision for credit losses 397 1,623 2,887 (203 ) 1,308 918 680 7,610 Charge-offs — (1,752 ) (2,255 ) (797 ) (372 ) (2,877 ) (947 ) (9,000 ) Recoveries 89 492 649 266 180 1,336 267 3,279 Net charge-offs 89 (1,260 ) (1,606 ) (531 ) (192 ) (1,541 ) (680 ) (5,721 ) Balance at September 30, 2017: Allowance for loan losses 4,852 18,987 9,648 3,372 4,489 3,379 760 45,487 Allowance for loan commitments 133 21 233 9 211 40 — 647 Total ending allowance for credit losses $ 4,985 $ 19,008 $ 9,881 $ 3,381 $ 4,700 $ 3,419 $ 760 $ 46,134 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 (unaudited, in thousands) Commercial Commercial Commercial Residential Estate Home Consumer Deposit Total September 30, 2018 Allowance for credit losses: Allowance for loans individually evaluated for impairment $ — $ — $ — $ — $ — $ — $ — $ — Allowance for loans collectively evaluated for impairment 4,169 20,824 12,051 3,775 4,290 2,796 997 48,902 Allowance for loan commitments 186 23 205 9 221 40 — 684 Total allowance for credit losses $ 4,355 $ 20,847 $ 12,256 $ 3,784 $ 4,511 $ 2,836 $ 997 $ 49,586 Portfolio loans: Individually evaluated for impairment (1) $ — $ — $ — $ — $ — $ — $ — $ — Collectively evaluated for impairment 537,699 3,361,315 1,291,296 1,595,547 604,106 325,419 — 7,715,382 Acquired with deteriorated credit quality 1,223 5,984 777 2,930 — 127 — 11,041 Total portfolio loans $ 538,922 $ 3,367,299 $ 1,292,073 $ 1,598,477 $ 604,106 $ 325,546 $ — $ 7,726,423 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: Commercial Loans by Internally Assigned Risk Grade (unaudited, in thousands) Commercial Commercial Commercial Total As of September 30, 2018 Pass $ 533,982 $ 3,314,324 $ 1,272,181 $ 5,120,487 Criticized—compromised 2,909 31,399 12,062 46,370 Classified—substandard 2,031 21,576 7,830 31,437 Classified—doubtful — — — — Total $ 538,922 $ 3,367,299 $ 1,292,073 $ 5,198,294 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 $20.6 million at September 30, 2018 and $22.8 million at December 31, 2017, of which $2.2 million 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 FFKT Loans 310-20 Loans acquired with deteriorated credit quality with a book value of $2.7 million were recorded at the preliminary fair value of $2.4 million, of which all were accounted for under the cost recovery method in accordance with ASC 310-30 non-accrual. The carrying amount of loans acquired with deteriorated credit quality at September 30, 2018 was $2.1 million, while the outstanding customer balance was $2.4 million. At September 30, 2018 no allowance for loan losses has been recognized related to the acquired impaired loans. Certain acquired underperforming loans with a book value of $45.2 million were transferred to loans held for sale prior to September 30, 2018 at the preliminary fair value of $35.2 million. Acquired FTSB Loans 310-20 Loans acquired with deteriorated credit quality with a book value of $4.1 million were recorded at the preliminary fair value of $2.0 million, of which $0.7 million were accounted for under the cost recovery method in accordance with ASC 310-30 non-accrual. The carrying amount of loans acquired with deteriorated credit quality at September 30, 2018 was $1.7 million, while the outstanding customer balance was $3.8 million. At September 30, 2018, no allowance for loan losses has been recognized related to the acquired impaired loans. Certain acquired underperforming loans with a book value of $4.0 million were transferred to loans held for sale prior to September 30, 2018 at the preliminary fair value of $2.8 million. Certain acquired underperforming loans with a book value of $17.7 million were sold in the second quarter of 2018 for $12.9 million. The acquisition date fair value of the acquired loans was adjusted to the sale price resulting in no gain or loss. The following table provides changes in accretable yield for loans acquired with deteriorated credit quality: For the Nine Months Ended (unaudited, in thousands) September 30, September 30, Balance at beginning of period $ 1,724 $ 1,717 Acquisitions 695 — Reduction due to change in projected cash flows (86 ) — Reclass from non-accretable difference 6,287 1,490 Transfers out — (216 ) Accretion (902 ) (1,384 ) Balance at end of period $ 7,718 $ 1,607 The following tables summarize the age analysis of all categories of loans: Age Analysis of Loans (unaudited, in thousands) Current 30-59 Days 60-89 Days 90 Days Total Total Loans 90 Days As of September 30, 2018 Commercial real estate: Land and construction $ 538,181 $ 643 $ 98 $ — $ 741 $ 538,922 $ — Improved property 3,357,883 1,657 352 7,407 9,416 3,367,299 88 Total commercial real estate 3,896,064 2,300 450 7,407 10,157 3,906,221 88 Commercial and industrial 1,287,693 776 462 3,142 4,380 1,292,073 114 Residential real estate 1,579,164 8,100 2,708 8,505 19,313 1,598,477 1,225 Home equity 596,477 2,871 1,002 3,756 7,629 604,106 646 Consumer 322,093 2,291 605 557 3,453 325,546 378 Total portfolio loans 7,681,491 16,338 5,227 23,367 44,932 7,726,423 2,451 Loans held for sale 55,913 — — — — 55,913 — Total loans $ 7,737,404 $ 16,338 $ 5,227 $ 23,367 $ 44,932 $ 7,782,336 $ 2,451 Impaired loans included above are as follows: Non-accrual $ 7,480 $ 1,653 $ 1,225 $ 20,916 $ 23,794 $ 31,274 TDRs accruing interest (1) 5,667 314 357 — 671 6,338 Total impaired $ 13,147 $ 1,967 $ 1,582 $ 20,916 $ 24,465 $ 37,612 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 September 30, 2018 December 31, 2017 (unaudited, in thousands) Unpaid Recorded Related Unpaid Recorded Related With no related specific allowance recorded: Commercial real estate: Land and construction $ — $ $ — $ 412 $ 239 $ — Improved property 14,639 9,928 — 18,229 12,863 — Commercial and industrial 3,886 3,327 — 3,745 3,086 — Residential real estate 21,226 18,944 — 20,821 18,982 — Home equity 5,550 4,728 — 5,833 5,169 — Consumer 857 685 — 1,084 952 — Total impaired loans without a specific allowance 46,158 37,612 — 50,124 41,291 — With a specific allowance recorded: Commercial real estate: Land and construction — — — — — — Improved property — — — 2,105 2,105 388 Commercial and industrial — — — — — — Total impaired loans with a specific allowance — — — 2,105 2,105 388 Total impaired loans $ 46,158 $ 37,612 $ — $ 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 For the Nine Months Ended September 30, 2018 September 30, 2017 September 30, 2018 September 30, 2017 (unaudited, in thousands) Average Interest Average Interest Average Interest Average Interest With no related specific allowance recorded: Commercial real estate: Land and construction $ — $ — $ 444 $ — $ 260 $ — $ 516 $ — Improved Property 10,409 15 10,923 31 11,000 383 10,271 400 Commercial and industrial 3,181 5 3,588 2 2,985 9 3,700 6 Residential real estate 18,336 68 17,039 57 18,207 195 17,743 192 Home equity 4,924 8 4,727 4 4,997 19 4,456 14 Consumer 692 3 731 2 776 8 746 5 Total impaired loans without a specific allowance 37,542 99 37,452 96 38,225 614 37,432 617 With a specific allowance recorded: Commercial real estate: Land and construction — — — — — — — — Improved Property — — 5,137 — 1,052 — 5,032 — Commercial and industrial — — — — — — 318 — Total impaired loans with a specific allowance — — 5,137 — 1,052 — 5,350 — Total impaired loans $ 37,542 $ 99 $ 42,589 $ 96 $ 39,277 $ 614 $ 42,782 $ 617 The following tables present the recorded investment in non-accrual Non-accrual (unaudited, in thousands) September 30, December 31, Commercial real estate: Land and construction $ — $ 239 Improved property 8,757 13,318 Total commercial real estate 8,757 13,557 Commercial and industrial 3,165 2,958 Residential real estate 14,475 14,661 Home equity 4,283 4,762 Consumer 594 887 Total $ 31,274 $ 36,825 (1) At September 30, 2018, there was one borrower with a loan greater than $1.0 million totaling $3.4 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 September 30, 2018 December 31, 2017 (unaudited, in thousands) Accruing Non-Accrual Total Accruing Non-Accrual Total Commercial real estate: Land and construction $ — $ — $ — $ — $ 3 $ 3 Improved property 1,171 640 1,811 1,650 428 2,078 Total commercial real estate 1,171 640 1,811 1,650 431 2,081 Commercial and industrial 162 — 162 128 97 225 Residential real estate 4,469 1,182 5,651 4,321 1,880 6,201 Home equity 445 167 612 407 337 744 Consumer 91 47 138 65 120 185 Total $ 6,338 $ 2,036 $ 8,374 $ 6,571 $ 2,865 $ 9,436 As of September 30, 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 and nine months ended September 30, 2018 and 2017, respectively: New TDRs (1) For the Three Months Ended September 30, 2018 September 30, 2017 (unaudited, dollars in thousands) Number of Pre- Post- Number of Pre- Post- Commercial real estate: Land and construction — $ — $ — — $ — $ — Improved Property — — — 1 190 185 Total commercial real estate — — — 1 190 185 Commercial and industrial — — — — — — Residential real estate — — — — — — Home equity — — — 2 94 88 Consumer 1 19 18 1 7 6 Total 1 $ 19 $ 18 4 $ 291 $ 279 (1) Excludes loans that were either paid off or charged-off pre-modification New TDRs (1) For the Nine Months Ended September 30, 2018 September 30, 2017 (unaudited, dollars in thousands) Number of Pre- Post- Number of Pre- Post- Commercial real estate: Land and construction — $ — $ — — $ — $ — Improved Property — — — 1 190 185 Total commercial real estate — — — 1 190 185 Commercial and industrial 1 10 8 1 64 59 Residential real estate 5 203 176 2 22 17 Home equity 1 20 19 3 141 132 Consumer 4 65 52 4 42 33 Total 11 $ 298 $ 255 11 $ 459 $ 426 (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 nine months ended September 30, 2018 and 2017, respectively, that were restructured within the last twelve months prior to September, 2018 and 2017, respectively: Defaulted TDRs (1) For the Nine Months Ended September 30, 2018 September 30, 2017 (unaudited, dollars in thousands) Number of Recorded Number of Recorded Commercial real estate: Land and construction — $ — — $ — Improved property — — — — Total commercial real estate — — — — Commercial and industrial — — — — Residential real estate 2 172 1 7 Home equity 1 6 — — Consumer — — 1 7 Total 3 $ 178 2 $ 14 (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: September 30, 2018 December 31, 2017 (unaudited, in thousands) Other real estate owned $ 6,836 $ 5,195 Repossessed assets 41 102 Total other real estate owned and repossessed assets $ 6,877 $ 5,297 Residential real estate included in other real estate owned at September 30, 2018 and December 31, 2017 was $0.7 million and $1.5 million, respectively. At September 30, 2018 and December 31, 2017, formal foreclosure proceedings were in process on residential real estate loans totaling $6.0 million and $3.5 million, respectively.

Derivatives and Hedging Activit

Derivatives and Hedging Activities	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	NOTE 6. 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 economically 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 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 September 30, 2018 and December 31, 2017, WesBanco had 42 and 39, respectively, interest rate swaps with an aggregate notional amount of $234.4 million and $298.2 million, respectively, related to this program. During the nine months ended September 30, 2018 and 2017, WesBanco recognized net losses of $0.1 million and $0.3 million, respectively, related to the changes in fair value of these swaps. Additionally, WesBanco recognized $1.4 million and $1.2 million of income for the related swap fees for the nine months ended September 30, 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 September 30, 2018 and December 31, 2017: September 30, 2018 December 31, 2017 (unaudited, in thousands) Notional or Asset Liability Notional or Asset Liability Derivatives Loan Swaps: Interest rate swaps $ 234,363 $ 6,451 $ 6,527 $ 298,223 $ 7,351 $ 7,345 Other contracts: Interest rate loan commitments 27,795 32 — 20,319 49 — Forward TBA contracts 32,000 148 — 31,750 — 23 Total derivatives $ 6,631 $ 6,527 $ 7,400 $ 7,368 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 For the Nine Months Ended (unaudited, in thousands) Location of Gain/(Loss) 2018 2017 2018 2017 Interest rate swaps Other income $ (293 ) $ (32 ) $ (82 ) $ (335 ) Interest rate loan commitments Mortgage banking income (111 ) — 32 123 Forward TBA contracts Mortgage banking income 131 — 530 — Total $ (273 ) $ (32 ) $ 480 $ (212 ) 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 $3.7 million as of September 30, 2018. If WesBanco had breached any of these provisions at September 30, 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	9 Months Ended
	Sep. 30, 2018
Retirement Benefits [Abstract]
Pension Plan	NOTE 7. 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 For the Nine Months Ended (unaudited, in thousands) 2018 2017 2018 2017 Service cost – benefits earned during year $ 715 $ 650 $ 2,121 $ 1,929 Interest cost on projected benefit obligation 1,242 1,107 3,684 3,287 Expected return on plan assets (2,416 ) (1,928 ) (7,169 ) (5,721 ) Amortization of prior service cost 6 7 19 19 Amortization of net loss 766 812 2,274 2,409 Net periodic pension cost $ 313 $ 648 $ 929 $ 1,923 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 made a voluntary contribution of $2.5 million to the Plan in June 2018. WesBanco assumed YCB’s obligation for a predecessor bank’s participation in a defined benefit plan. The net periodic pension income for this plan for the three and nine months ended September 30, 2018 was $0.1 million and $0.2 million, respectively, which was comprised of a $0.2 million and a $0.5 million expected return on plan assets and net actuarial gain, partially offset by a $0.1 million and a $0.3 million interest cost on projected benefit obligation for the three and nine months ended September 30, 2018, respectively. No minimum contribution is due for this plan for fiscal year 2018; however, WesBanco made a voluntary contribution of $0.2 million to this plan in June 2018. WesBanco assumed FFKT’s postretirement medical benefit plan, which had a liability totaling $15.0 million at the acquisition date. The plan covers FFKT employees who were hired before January 1, 2016 and meet certain age and length of full-time service requirements. The plan was modified in August 2018, which reduced the number of eligible employees. The modification resulted in a $5.5 million unrealized gain, which was recorded in Accumulated Other Comprehensive Income net of tax and will be recognized over the life of the plan participants estimated to be approximately 17 years. The modification reduced the plan liability to $9.5 million as of September 30, 2018.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement	NOTE 8. 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 September 30, 2018 and December 31, 2017: September 30, 2018 Fair Value Measurements Using: (unaudited, in thousands) September 30, Quoted Prices in Significant Significant Investments Recurring fair value measurements Equity securities $ 12,784 $ 12,784 $ — $ — $ — Debt securities—available-for-sale U.S. Treasury 9,937 — 9,937 — — U.S. Government sponsored entities and agencies 149,949 — 149,949 — — Residential mortgage-backed securities and 1,449,754 — 1,449,754 — — Commercial mortgage-backed securities and 168,761 — 168,761 — — Obligations of state and political subdivisions 186,651 — 185,125 1,526 — Corporate debt securities 43,180 — 43,180 — — Total debt securities—available-for-sale $ 2,008,232 $ — $ 2,006,706 $ 1,526 $ — Loans held for sale 55,913 — 55,913 — — Other assets—interest rate derivatives agreements 6,451 — 6,451 — — Total assets recurring fair value measurements $ 2,083,380 $ 12,784 $ 2,069,070 $ 1,526 $ — Other liabilities—interest rate derivatives agreements $ 6,527 $ — $ 6,527 $ — $ — Total liabilities recurring fair value measurements $ 6,527 $ — $ 6,527 $ — $ — Nonrecurring fair value measurements Impaired loans $ — $ — $ — $ — $ — Other real estate owned and repossessed assets 6,877 — — 6,877 — Total nonrecurring fair value measurements $ 6,877 $ — $ — $ 6,877 $ — December 31, 2017 Fair Value Measurements Using: (unaudited, in thousands) December 31, Quoted Prices in Significant Significant Investments 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 934,922 — 934,922 — — Commercial mortgage-backed securities and 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 and nine months ended September 30, 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 (unaudited, in thousands) Fair Value Valuation Unobservable Range (Weighted September 30, 2018 Impaired loans $ — Appraisal of collateral (1) Appraisal adjustments (2) — Liquidation expenses (2) — Other real estate owned and repossessed assets 6,877 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 September 30, 2018 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Significant Other Significant Investments Financial Assets Cash and due from banks $ 273,680 $ 273,680 $ 273,680 $ — $ — $ — Equity securities 12,784 12,784 12,784 — — — Debt securities available-for-sale 2,008,232 2,008,232 — 2,006,706 1,526 — Debt securities held-to-maturity 1,025,538 1,014,361 — 1,013,788 573 — Net loans 7,677,521 7,517,958 — — 7,517,958 — Loans held for sale 55,913 55,913 — 55,913 — — Other assets—interest rate derivatives 6,451 6,451 — 6,451 — — Accrued interest receivable 39,465 39,465 39,465 — — — Financial Liabilities Deposits 8,941,758 8,960,221 7,428,158 1,532,063 — — Federal Home Loan Bank borrowings 1,131,253 1,123,441 — 1,123,441 — — Other borrowings 294,281 294,285 292,290 1,995 — — Subordinated debt and junior subordinated debt 189,745 179,497 — 179,497 — — Other liabilities—interest rate derivatives 6,527 6,527 — 6,527 — — Accrued interest payable 6,623 6,623 6,623 — — — Fair Value Measurements at December 31, 2017 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Significant Other Significant Investments 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	9 Months Ended
	Sep. 30, 2018
Text Block [Abstract]
Revenue Recognition	NOTE 9. REVENUE RECOGNITION WesBanco adopted ASU 2014-09 Trust fees: Service charges on deposits: Allotment fees: 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 and nine months ended September 30, 2018: (unaudited, in thousands) Point of Revenue Recognition For the Three For the Nine Revenue Streams Trust fees Trust account fees Over time $ 4,006 $ 11,856 WesMark fees Over time 2,259 6,664 Total trust fees 6,265 18,520 Service charges on deposits Commercial banking fees Over time 563 1,406 Personal service charges At a point in time & over time 5,750 14,876 Total service charges on deposits 6,313 16,282 Net securities brokerage revenue Annuity commissions At a point in time 1,326 3,836 Equity and debt security trades At a point in time 116 304 Managed money Over time 173 477 Trail commissions Over time 221 698 Total net securities brokerage revenue 1,836 5,315 Allotment fees (1) At a point in time & over time 311 311 Electronic banking fees At a point in time 6,139 16,697 Mortgage banking income At a point in time 1,521 4,297 Net gain or loss on sale of other real estate owned At a point in time 150 641 (1) Allotment fees are included in other non-interest

Comprehensive Income_(Loss)

Comprehensive Income/(Loss)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Comprehensive Income/(Loss)	NOTE 10. COMPREHENSIVE INCOME/(LOSS) The activity in accumulated other comprehensive income for the nine months ended September 30, 2018 and 2017 is as follows: Accumulated Other Comprehensive Income/(Loss) (1) (unaudited, in thousands) Defined Unrealized Available-for-Sale Unrealized Gains 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 — (33,013 ) — (33,013 ) Acquired FFKT Medical benefit plan 4,235 — — 4,235 Amounts reclassified from accumulated other comprehensive income 1,621 (9 ) (149 ) 1,463 Period change 5,856 (33,022 ) (149 ) (27,315 ) Adoption of Accounting Standard ASU 2016-01 (2) — (1,063 ) — (1,063 ) Balance at September 30, 2018 $ (12,770 ) $ (47,335 ) $ 232 $ (59,873 ) Balance at December 31, 2016 $ (17,758 ) $ (9,890 ) $ 522 $ (27,126 ) Other comprehensive income before reclassifications — 4,740 — 4,740 Amounts reclassified from accumulated other comprehensive income 1,679 35 (165 ) 1,549 Period change 1,679 4,775 (165 ) 6,289 Balance at September 30, 2017 $ (16,079 ) $ (5,115 ) $ 357 $ (20,837 ) (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 and nine months ended September 30, 2018 and 2017, respectively: Details about Accumulated Other Comprehensive Income Components (unaudited, in thousands) For the Three For the Nine Affected Line Item in the Statement of 2018 2017 2018 2017 Securities available-for-sale (1) Net securities gains/losses reclassified into earnings $ (11 ) $ — $ (11 ) $ 55 Net securities gains (Non-interest Related income tax benefit 2 — 2 (20 ) Provision for income taxes Net effect on accumulated other comprehensive income for the period (9 ) — (9 ) 35 Securities held-to-maturity (1) Amortization of unrealized gain transferred from available-for-sale (64 ) (66 ) (195 ) (256 ) Interest and dividends on securities (Interest and dividend income) Related income tax expense 15 24 46 91 Provision for income taxes Net effect on accumulated other comprehensive income for the period (49 ) (42 ) (149 ) (165 ) Defined benefit plans (2) Amortization of net loss and prior service costs 772 816 2,293 2,429 Employee benefits (Non-interest Related income tax benefit (177 ) (303 ) (672 ) (750 ) Provision for income taxes Net effect on accumulated other comprehensive income for the period 595 513 1,621 1,679 Total reclassifications for the period $ 537 $ 471 $ 1,463 $ 1,549 (1) For additional detail related to unrealized gains on securities and related amounts reclassified from accumulated other comprehensive income, see Note 4, “Securities.” (2) Included in the computation of net periodic pension cost. See Note 7, “Pension and Other Post Retirement Benefits” for additional detail.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	NOTE 11. 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 September 30, 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 any loan balances that default. The following table presents total commitments to extend credit, guarantees and various letters of credit outstanding: (unaudited, in thousands) September 30, December 31, Lines of credit $ 1,855,388 $ 1,452,697 Loans approved but not closed 349,173 245,644 Overdraft limits 154,221 126,671 Letters of credit 41,515 31,951 Contingent obligations and other guarantees 5,725 6,700 Contingent Liabilities —

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Business Segments	NOTE 12. 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: (unaudited, in thousands) Community Trust and Consolidated For the Three Months ended September 30, 2018: Interest income $ 108,393 $ — $ 108,393 Interest expense 18,460 — 18,460 Net interest income 89,933 — 89,933 Provision for credit losses 1,035 — 1,035 Net interest income after provision for credit losses 88,898 — 88,898 Non-interest 19,959 6,265 26,224 Non-interest 72,378 3,742 76,120 Income before provision for income taxes 36,479 2,523 39,002 Provision for income taxes 5,986 530 6,516 Net income $ 30,493 $ 1,993 $ 32,486 For the Three Months ended September 30, 2017: Interest income $ 85,489 $ — $ 85,489 Interest expense 11,235 — 11,235 Net interest income 74,254 — 74,254 Provision for credit losses 2,516 — 2,516 Net interest income after provision for credit losses 71,738 — 71,738 Non-interest 15,541 5,358 20,899 Non-interest 52,355 3,399 55,754 Income before provision for income taxes 34,924 1,959 36,883 Provision for income taxes 9,744 783 10,527 Net income $ 25,180 $ 1,176 $ 26,356 For the Nine Months ended September 30, 2018: Interest income $ 293,596 $ — $ 293,596 Interest expense 48,127 — 48,127 Net interest income 245,469 — 245,469 Provision for credit losses 4,911 — 4,911 Net interest income after provision for credit losses 240,558 — 240,558 Non-interest 55,195 18,520 73,715 Non-interest 183,298 10,936 194,234 Income before provision for income taxes 112,455 7,584 120,039 Provision for income taxes 19,262 1,593 20,855 Net income $ 93,193 $ 5,991 $ 99,184 For the Nine Months ended September 30, 2017: Interest income $ 247,573 $ — $ 247,573 Interest expense 30,461 — 30,461 Net interest income 217,112 — 217,112 Provision for credit losses 7,610 — 7,610 Net interest income after provision for credit losses 209,502 — 209,502 Non-interest 48,833 17,073 65,906 Non-interest 156,102 9,921 166,023 Income before provision for income taxes 102,233 7,152 109,385 Provision for income taxes 27,940 2,861 30,801 Net income $ 74,293 $ 4,291 $ 78,584 Total non-fiduciary

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 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 — 2018-15, Other—Internal-Use 350-40): internal-use internal-use 2018-15 In August 2018, the FASB issued ASU 2018-14, 715-20): 715-20 2018-14 In August 2018, the FASB issued ASU 2018-13, 2018-13 In August 2017, the FASB issued ASU 2017-12, 2017-12 In March 2017, the FASB issued ASU 2017-07 non-interest In January 2017, the FASB issued ASU 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 September 2016, the FASB issued ASU 2016-13 held-to-maturity available-for-sale In February 2016, the FASB issued ASU 2016-02 2018-01, 2018-10, 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,

Mergers and Acquisitions (Table

Mergers and Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2018
First Sentry Bancshares, Inc. [Member]
Summary of Preliminary Purchase Price of Acquisition and Resulting Goodwill	The preliminary purchase price of the FTSB acquisition and resulting goodwill is summarized as follows: (unaudited, in thousands) April 5, 2018 Purchase Price: Fair value of WesBanco shares issued $ 107,347 Cash consideration for outstanding FTSB shares 975 Total purchase price $ 108,322 Fair value of: Tangible assets acquired $ 610,443 Core deposit and other intangible assets acquired 8,078 Liabilities assumed (664,172 ) Net cash received in the acquisition 87,124 Fair value of net assets acquired 41,473 Goodwill recognized $ 66,849
Allocation of Purchase Price of Assets Acquired and Liabilities Assumed	The following table presents the preliminary allocation of the purchase price of the assets acquired and the liabilities assumed at the date of acquisition, as WesBanco intends to finalize its accounting for the acquisition of FTSB within one year from the date of acquisition: (unaudited, in thousands) April 5, 2018 Assets acquired Cash and due from banks $ 87,124 Securities 142,903 Loans 448,075 Goodwill and other intangible assets 74,927 Accrued income and other assets 19,465 Total assets acquired $ 772,494 Liabilities assumed Deposits $ 590,065 Borrowings 70,710 Accrued expenses and other liabilities 3,397 Total liabilities assumed $ 664,172 Net assets acquired $ 108,322
Purchase Price Allocation Adjustment [Member]
Allocation of Purchase Price of Assets Acquired and Liabilities Assumed	The following table presents the changes in the allocation of the purchase price of the assets acquired and the liabilities assumed at the date of the acquisition previously reported as of June 30, 2018: (unaudited, in thousands) April 5, 2018 Goodwill recognized as of June 30, 2018 $ 66,219 Change in fair value of net assets acquired: Assets Loans (264 ) Other intangible assets (159 ) Accrued income and other assets (6 ) Liabilities Deposits (47 ) Accrued expenses and other liabilities (154 ) Fair value of net assets acquired $ (630 ) Increase in goodwill recognized 630 Goodwill recognized as of September 30, 2018 $ 66,849
Farmers Capital Bank Corporation [Member]
Summary of Preliminary Purchase Price of Acquisition and Resulting Goodwill	The preliminary purchase price of the FFKT acquisition and resulting goodwill is summarized as follows: (unaudited, in thousands) August 20, 2018 Purchase Price: Fair value of WesBanco shares issued $ 391,267 Cash consideration for outstanding FFKT shares 37,634 Total purchase price $ 428,901 Fair value of: Tangible assets acquired $ 1,360,951 Core deposit and other intangible assets acquired 42,593 Liabilities assumed (1,429,874 ) Net cash received in the acquisition 230,139 Fair value of net assets acquired 203,809 Goodwill recognized $ 225,092
Allocation of Purchase Price of Assets Acquired and Liabilities Assumed	The following table presents the preliminary allocation of the purchase price of the assets acquired and the liabilities assumed at the date of acquisition, as WesBanco intends to finalize its accounting for the acquisition of FFKT within one year from the date of acquisition: (unaudited, in thousands) August 20, 2018 Assets acquired Cash and due from banks $ 230,139 Securities 239,321 Loans 1,028,120 Goodwill and other intangible assets 267,685 Accrued income and other assets 93,510 Total assets acquired $ 1,858,775 Liabilities assumed Deposits $ 1,330,328 Borrowings 71,780 Accrued expenses and other liabilities 27,766 Total liabilities assumed $ 1,429,874 Net assets acquired $ 428,901

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Summary of Earnings Per Common Share	Earnings per common share are calculated as follows: For the Three Months Ended For the Nine Months Ended (unaudited, in thousands, except shares and per share amounts) 2018 2017 2018 2017 Numerator for both basic and diluted earnings per common share: Net income $ 32,486 $ 26,356 $ 99,184 $ 78,584 Denominator: Total average basic common shares outstanding 50,277,847 44,031,813 46,965,095 43,992,017 Effect of dilutive stock options and other stock compensation 154,265 55,068 142,734 67,452 Total diluted average common shares outstanding 50,432,112 44,086,881 47,107,829 44,059,469 Earnings per common share—basic $ 0.65 $ 0.60 $ 2.11 $ 1.79 Earnings per common share—diluted $ 0.64 $ 0.60 $ 2.11 $ 1.78

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2018 December 31, 2017 (unaudited, in thousands) Amortized Cost Gross Gross Estimated Amortized Gross Gross Estimated Available-for-sale U.S. Treasury $ 9,952 $ — $ (15 ) $ 9,937 $ — $ — $ — $ — U.S. Government sponsored entities and agencies 154,054 17 (4,122 ) 149,949 72,425 24 (606 ) 71,843 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 1,500,563 44 (50,853 ) 1,449,754 954,115 214 (19,407 ) 934,922 Commerical mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 174,331 15 (5,585 ) 168,761 116,448 4 (1,585 ) 114,867 Obligations of states and political subdivisions 187,501 1,445 (2,295 ) 186,651 102,363 2,927 (460 ) 104,830 Corporate debt securities 43,259 160 (239 ) 43,180 35,234 228 (59 ) 35,403 Total available-for-sale $ 2,069,660 $ 1,681 $ (63,109 ) $ 2,008,232 $ 1,280,585 $ 3,397 $ (22,117 ) $ 1,261,865 Held-to-maturity U.S. Government sponsored entities and agencies $ 11,699 $ — $ (615 ) $ 11,084 $ 11,465 $ — $ (325 ) $ 11,140 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 154,018 103 (6,788 ) 147,333 170,025 544 (2,609 ) 167,960 Obligations of states and political subdivisions 826,514 6,434 (9,743 ) 823,205 794,655 17,364 (1,609 ) 810,410 Corporate debt securities 33,307 5 (573 ) 32,739 33,355 919 — 34,274 Total held-to-maturity $ 1,025,538 $ 6,542 $ (17,719 ) $ 1,014,361 $ 1,009,500 $ 18,827 $ (4,543 ) $ 1,023,784 Total debt securities $ 3,095,198 $ 8,223 $ (80,828 ) $ 3,022,593 $ 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 September 30, 2018 (unaudited, in thousands) One Year One to Five to After Mortgage-backed Total Available-for-sale U.S. Treasury $ 9,937 $ — $ — $ — $ — $ 9,937 U.S. Government sponsored entities and agencies 10,479 6,260 17,881 15,298 100,031 149,949 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 1,449,754 1,449,754 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 168,761 168,761 Obligations of states and political subdivisions 9,288 48,959 76,972 51,432 — 186,651 Corporate debt securities 8,014 33,251 1,915 — — 43,180 Total available-for-sale $ 37,718 $ 88,470 $ 96,768 $ 66,730 $ 1,718,546 $ 2,008,232 Held-to-maturity U.S. Government sponsored entities and agencies $ — $ — $ — $ — $ 11,084 $ 11,084 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies (1) — — — — 147,333 147,333 Obligations of states and political subdivisions 6,149 138,709 387,775 290,572 — 823,205 Corporate debt securities — 7,449 25,290 — — 32,739 Total held-to-maturity $ 6,149 $ 146,158 $ 413,065 $ 290,572 $ 158,417 $ 1,014,361 Total debt securities $ 43,867 $ 234,628 $ 509,833 $ 357,302 $ 1,876,963 $ 3,022,593 (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 For the Nine Months Ended (unaudited, in thousands) 2018 2017 2018 2017 Debt securities: Gross realized gains $ 88 $ 29 $ 100 $ 603 Gross realized losses (13 ) (23 ) (31 ) (92 ) Net gains on debt securities $ 75 $ 6 $ 69 $ 511 Equity securities: Unrealized gains recognized on securities still held $ 11 $ — $ 330 $ — Net realized (losses) gains recognized on securities sold (2 ) — 4 — Net gains on equity securities $ 9 $ — $ 334 $ — Net securities gains $ 84 $ 6 $ 403 $ 511
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 September 30, 2018 and December 31, 2017: September 30, 2018 Less than 12 months 12 months or more Total (unaudited, dollars in thousands) Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of U.S. Treasury $ 9,937 $ (15 ) 1 $ — $ — — $ 9,937 $ (15 ) 1 U.S. Government sponsored entities and agencies 93,881 (2,264 ) 38 60,410 (2,473 ) 11 154,291 (4,737 ) 49 Residential mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 759,415 (13,670 ) 188 822,774 (43,971 ) 260 1,582,189 (57,641 ) 448 Commercial mortgage-backed securities and collateralized mortgage obligations of government sponsored entities and agencies 79,056 (1,239 ) 15 86,703 (4,346 ) 11 165,759 (5,585 ) 26 Obligations of states and political subdivisions 493,252 (7,866 ) 855 120,843 (4,172 ) 236 614,095 (12,038 ) 1091 Corporate debt securities 42,816 (738 ) 17 1,915 (74 ) 1 44,731 (812 ) 18 Total temporarily impaired securities $ 1,478,357 $ (25,792 ) 1,114 $ 1,092,645 $ (55,036 ) 519 $ 2,571,002 $ (80,828 ) 1,633 December 31, 2017 Less than 12 months 12 months or more Total (unaudited, dollars in thousands) Fair Unrealized # of Fair Unrealized # of Fair Unrealized # of 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 C_2

Loans and the Allowance for Credit Losses (Tables)	9 Months Ended
	Sep. 30, 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 $2.8 million and $1.6 million at September 30, 2018 and December 31, 2017, respectively. The unamortized discount on purchased portfolio loans from acquisitions was $54.3 million, including $6.7 million related to FTSB and $25.9 million related to FFKT, and $21.9 million at September 30, 2018 and December 31, 2017, respectively. (unaudited, in thousands) September 30, December 31, Commercial real estate: Land and construction $ 538,922 $ 392,597 Improved property 3,367,299 2,601,851 Total commercial real estate 3,906,221 2,994,448 Commercial and industrial 1,292,073 1,125,327 Residential real estate 1,598,477 1,353,301 Home equity 604,106 529,196 Consumer 325,546 339,169 Total portfolio loans 7,726,423 6,341,441 Loans held for sale 55,913 20,320 Total loans $ 7,782,336 $ 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 Nine Months Ended September 30, 2018 and 2017 (unaudited, in thousands) Commercial Commercial Real Estate - Commercial Residential Home Consumer Deposit 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 789 (721 ) 2,538 1,106 (292 ) 541 840 4,801 Provision for loan commitments 67 (3 ) 32 2 9 3 — 110 Total provision for credit losses 856 (724 ) 2,570 1,108 (283 ) 544 840 4,911 Charge-offs (137 ) (719 ) (871 ) (873 ) (745 ) (2,465 ) (941 ) (6,751 ) Recoveries 400 1,098 970 336 830 1,657 277 5,568 Net charge-offs 263 379 99 (537 ) 85 (808 ) (664 ) (1,183 ) Balance at September 30, 2018: Allowance for loan losses 4,169 20,824 12,051 3,775 4,290 2,796 997 48,902 Allowance for loan commitments 186 23 205 9 221 40 — 684 Total ending allowance for credit losses $ 4,355 $ 20,847 $ 12,256 $ 3,784 $ 4,511 $ 2,836 $ 997 $ 49,586 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 415 1,619 2,842 (203 ) 1,259 922 680 7,534 Provision for loan commitments (18 ) 4 45 — 49 (4 ) — 76 Total provision for credit losses 397 1,623 2,887 (203 ) 1,308 918 680 7,610 Charge-offs — (1,752 ) (2,255 ) (797 ) (372 ) (2,877 ) (947 ) (9,000 ) Recoveries 89 492 649 266 180 1,336 267 3,279 Net charge-offs 89 (1,260 ) (1,606 ) (531 ) (192 ) (1,541 ) (680 ) (5,721 ) Balance at September 30, 2017: Allowance for loan losses 4,852 18,987 9,648 3,372 4,489 3,379 760 45,487 Allowance for loan commitments 133 21 233 9 211 40 — 647 Total ending allowance for credit losses $ 4,985 $ 19,008 $ 9,881 $ 3,381 $ 4,700 $ 3,419 $ 760 $ 46,134
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 (unaudited, in thousands) Commercial Commercial Commercial Residential Estate Home Consumer Deposit Total September 30, 2018 Allowance for credit losses: Allowance for loans individually evaluated for impairment $ — $ — $ — $ — $ — $ — $ — $ — Allowance for loans collectively evaluated for impairment 4,169 20,824 12,051 3,775 4,290 2,796 997 48,902 Allowance for loan commitments 186 23 205 9 221 40 — 684 Total allowance for credit losses $ 4,355 $ 20,847 $ 12,256 $ 3,784 $ 4,511 $ 2,836 $ 997 $ 49,586 Portfolio loans: Individually evaluated for impairment (1) $ — $ — $ — $ — $ — $ — $ — $ — Collectively evaluated for impairment 537,699 3,361,315 1,291,296 1,595,547 604,106 325,419 — 7,715,382 Acquired with deteriorated credit quality 1,223 5,984 777 2,930 — 127 — 11,041 Total portfolio loans $ 538,922 $ 3,367,299 $ 1,292,073 $ 1,598,477 $ 604,106 $ 325,546 $ — $ 7,726,423 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: Commercial Loans by Internally Assigned Risk Grade (unaudited, in thousands) Commercial Commercial Commercial Total As of September 30, 2018 Pass $ 533,982 $ 3,314,324 $ 1,272,181 $ 5,120,487 Criticized—compromised 2,909 31,399 12,062 46,370 Classified—substandard 2,031 21,576 7,830 31,437 Classified—doubtful — — — — Total $ 538,922 $ 3,367,299 $ 1,292,073 $ 5,198,294 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 Nine Months Ended (unaudited, in thousands) September 30, September 30, Balance at beginning of period $ 1,724 $ 1,717 Acquisitions 695 — Reduction due to change in projected cash flows (86 ) — Reclass from non-accretable difference 6,287 1,490 Transfers out — (216 ) Accretion (902 ) (1,384 ) Balance at end of period $ 7,718 $ 1,607
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 60-89 Days 90 Days Total Total Loans 90 Days As of September 30, 2018 Commercial real estate: Land and construction $ 538,181 $ 643 $ 98 $ — $ 741 $ 538,922 $ — Improved property 3,357,883 1,657 352 7,407 9,416 3,367,299 88 Total commercial real estate 3,896,064 2,300 450 7,407 10,157 3,906,221 88 Commercial and industrial 1,287,693 776 462 3,142 4,380 1,292,073 114 Residential real estate 1,579,164 8,100 2,708 8,505 19,313 1,598,477 1,225 Home equity 596,477 2,871 1,002 3,756 7,629 604,106 646 Consumer 322,093 2,291 605 557 3,453 325,546 378 Total portfolio loans 7,681,491 16,338 5,227 23,367 44,932 7,726,423 2,451 Loans held for sale 55,913 — — — — 55,913 — Total loans $ 7,737,404 $ 16,338 $ 5,227 $ 23,367 $ 44,932 $ 7,782,336 $ 2,451 Impaired loans included above are as follows: Non-accrual $ 7,480 $ 1,653 $ 1,225 $ 20,916 $ 23,794 $ 31,274 TDRs accruing interest (1) 5,667 314 357 — 671 6,338 Total impaired $ 13,147 $ 1,967 $ 1,582 $ 20,916 $ 24,465 $ 37,612 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 September 30, 2018 December 31, 2017 (unaudited, in thousands) Unpaid Recorded Related Unpaid Recorded Related With no related specific allowance recorded: Commercial real estate: Land and construction $ — $ $ — $ 412 $ 239 $ — Improved property 14,639 9,928 — 18,229 12,863 — Commercial and industrial 3,886 3,327 — 3,745 3,086 — Residential real estate 21,226 18,944 — 20,821 18,982 — Home equity 5,550 4,728 — 5,833 5,169 — Consumer 857 685 — 1,084 952 — Total impaired loans without a specific allowance 46,158 37,612 — 50,124 41,291 — With a specific allowance recorded: Commercial real estate: Land and construction — — — — — — Improved property — — — 2,105 2,105 388 Commercial and industrial — — — — — — Total impaired loans with a specific allowance — — — 2,105 2,105 388 Total impaired loans $ 46,158 $ 37,612 $ — $ 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 For the Nine Months Ended September 30, 2018 September 30, 2017 September 30, 2018 September 30, 2017 (unaudited, in thousands) Average Interest Average Interest Average Interest Average Interest With no related specific allowance recorded: Commercial real estate: Land and construction $ — $ — $ 444 $ — $ 260 $ — $ 516 $ — Improved Property 10,409 15 10,923 31 11,000 383 10,271 400 Commercial and industrial 3,181 5 3,588 2 2,985 9 3,700 6 Residential real estate 18,336 68 17,039 57 18,207 195 17,743 192 Home equity 4,924 8 4,727 4 4,997 19 4,456 14 Consumer 692 3 731 2 776 8 746 5 Total impaired loans without a specific allowance 37,542 99 37,452 96 38,225 614 37,432 617 With a specific allowance recorded: Commercial real estate: Land and construction — — — — — — — — Improved Property — — 5,137 — 1,052 — 5,032 — Commercial and industrial — — — — — — 318 — Total impaired loans with a specific allowance — — 5,137 — 1,052 — 5,350 — Total impaired loans $ 37,542 $ 99 $ 42,589 $ 96 $ 39,277 $ 614 $ 42,782 $ 617
Recorded Investment in Non-Accrual Loans and TDRs	The following tables present the recorded investment in non-accrual Non-accrual (unaudited, in thousands) September 30, December 31, Commercial real estate: Land and construction $ — $ 239 Improved property 8,757 13,318 Total commercial real estate 8,757 13,557 Commercial and industrial 3,165 2,958 Residential real estate 14,475 14,661 Home equity 4,283 4,762 Consumer 594 887 Total $ 31,274 $ 36,825 (1) At September 30, 2018, there was one borrower with a loan greater than $1.0 million totaling $3.4 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 September 30, 2018 December 31, 2017 (unaudited, in thousands) Accruing Non-Accrual Total Accruing Non-Accrual Total Commercial real estate: Land and construction $ — $ — $ — $ — $ 3 $ 3 Improved property 1,171 640 1,811 1,650 428 2,078 Total commercial real estate 1,171 640 1,811 1,650 431 2,081 Commercial and industrial 162 — 162 128 97 225 Residential real estate 4,469 1,182 5,651 4,321 1,880 6,201 Home equity 445 167 612 407 337 744 Consumer 91 47 138 65 120 185 Total $ 6,338 $ 2,036 $ 8,374 $ 6,571 $ 2,865 $ 9,436 As of September 30, 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 and nine months ended September 30, 2018 and 2017, respectively: New TDRs (1) For the Three Months Ended September 30, 2018 September 30, 2017 (unaudited, dollars in thousands) Number of Pre- Post- Number of Pre- Post- Commercial real estate: Land and construction — $ — $ — — $ — $ — Improved Property — — — 1 190 185 Total commercial real estate — — — 1 190 185 Commercial and industrial — — — — — — Residential real estate — — — — — — Home equity — — — 2 94 88 Consumer 1 19 18 1 7 6 Total 1 $ 19 $ 18 4 $ 291 $ 279 (1) Excludes loans that were either paid off or charged-off pre-modification New TDRs (1) For the Nine Months Ended September 30, 2018 September 30, 2017 (unaudited, dollars in thousands) Number of Pre- Post- Number of Pre- Post- Commercial real estate: Land and construction — $ — $ — — $ — $ — Improved Property — — — 1 190 185 Total commercial real estate — — — 1 190 185 Commercial and industrial 1 10 8 1 64 59 Residential real estate 5 203 176 2 22 17 Home equity 1 20 19 3 141 132 Consumer 4 65 52 4 42 33 Total 11 $ 298 $ 255 11 $ 459 $ 426 (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 nine months ended September 30, 2018 and 2017, respectively, that were restructured within the last twelve months prior to September, 2018 and 2017, respectively: Defaulted TDRs (1) For the Nine Months Ended September 30, 2018 September 30, 2017 (unaudited, dollars in thousands) Number of Recorded Number of Recorded Commercial real estate: Land and construction — $ — — $ — Improved property — — — — Total commercial real estate — — — — Commercial and industrial — — — — Residential real estate 2 172 1 7 Home equity 1 6 — — Consumer — — 1 7 Total 3 $ 178 2 $ 14 (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: September 30, 2018 December 31, 2017 (unaudited, in thousands) Other real estate owned $ 6,836 $ 5,195 Repossessed assets 41 102 Total other real estate owned and repossessed assets $ 6,877 $ 5,297

Derivatives and Hedging Activ_2

Derivatives and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2018 and December 31, 2017: September 30, 2018 December 31, 2017 (unaudited, in thousands) Notional or Asset Liability Notional or Asset Liability Derivatives Loan Swaps: Interest rate swaps $ 234,363 $ 6,451 $ 6,527 $ 298,223 $ 7,351 $ 7,345 Other contracts: Interest rate loan commitments 27,795 32 — 20,319 49 — Forward TBA contracts 32,000 148 — 31,750 — 23 Total derivatives $ 6,631 $ 6,527 $ 7,400 $ 7,368
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 For the Nine Months Ended (unaudited, in thousands) Location of Gain/(Loss) 2018 2017 2018 2017 Interest rate swaps Other income $ (293 ) $ (32 ) $ (82 ) $ (335 ) Interest rate loan commitments Mortgage banking income (111 ) — 32 123 Forward TBA contracts Mortgage banking income 131 — 530 — Total $ (273 ) $ (32 ) $ 480 $ (212 )

Pension Plan (Tables)

Pension Plan (Tables)	9 Months Ended
	Sep. 30, 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 For the Nine Months Ended (unaudited, in thousands) 2018 2017 2018 2017 Service cost – benefits earned during year $ 715 $ 650 $ 2,121 $ 1,929 Interest cost on projected benefit obligation 1,242 1,107 3,684 3,287 Expected return on plan assets (2,416 ) (1,928 ) (7,169 ) (5,721 ) Amortization of prior service cost 6 7 19 19 Amortization of net loss 766 812 2,274 2,409 Net periodic pension cost $ 313 $ 648 $ 929 $ 1,923

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2018 and December 31, 2017: September 30, 2018 Fair Value Measurements Using: (unaudited, in thousands) September 30, Quoted Prices in Significant Significant Investments Recurring fair value measurements Equity securities $ 12,784 $ 12,784 $ — $ — $ — Debt securities—available-for-sale U.S. Treasury 9,937 — 9,937 — — U.S. Government sponsored entities and agencies 149,949 — 149,949 — — Residential mortgage-backed securities and 1,449,754 — 1,449,754 — — Commercial mortgage-backed securities and 168,761 — 168,761 — — Obligations of state and political subdivisions 186,651 — 185,125 1,526 — Corporate debt securities 43,180 — 43,180 — — Total debt securities—available-for-sale $ 2,008,232 $ — $ 2,006,706 $ 1,526 $ — Loans held for sale 55,913 — 55,913 — — Other assets—interest rate derivatives agreements 6,451 — 6,451 — — Total assets recurring fair value measurements $ 2,083,380 $ 12,784 $ 2,069,070 $ 1,526 $ — Other liabilities—interest rate derivatives agreements $ 6,527 $ — $ 6,527 $ — $ — Total liabilities recurring fair value measurements $ 6,527 $ — $ 6,527 $ — $ — Nonrecurring fair value measurements Impaired loans $ — $ — $ — $ — $ — Other real estate owned and repossessed assets 6,877 — — 6,877 — Total nonrecurring fair value measurements $ 6,877 $ — $ — $ 6,877 $ — December 31, 2017 Fair Value Measurements Using: (unaudited, in thousands) December 31, Quoted Prices in Significant Significant Investments 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 934,922 — 934,922 — — Commercial mortgage-backed securities and 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 (unaudited, in thousands) Fair Value Valuation Unobservable Range (Weighted September 30, 2018 Impaired loans $ — Appraisal of collateral (1) Appraisal adjustments (2) — Liquidation expenses (2) — Other real estate owned and repossessed assets 6,877 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 September 30, 2018 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Significant Other Significant Investments Financial Assets Cash and due from banks $ 273,680 $ 273,680 $ 273,680 $ — $ — $ — Equity securities 12,784 12,784 12,784 — — — Debt securities available-for-sale 2,008,232 2,008,232 — 2,006,706 1,526 — Debt securities held-to-maturity 1,025,538 1,014,361 — 1,013,788 573 — Net loans 7,677,521 7,517,958 — — 7,517,958 — Loans held for sale 55,913 55,913 — 55,913 — — Other assets—interest rate derivatives 6,451 6,451 — 6,451 — — Accrued interest receivable 39,465 39,465 39,465 — — — Financial Liabilities Deposits 8,941,758 8,960,221 7,428,158 1,532,063 — — Federal Home Loan Bank borrowings 1,131,253 1,123,441 — 1,123,441 — — Other borrowings 294,281 294,285 292,290 1,995 — — Subordinated debt and junior subordinated debt 189,745 179,497 — 179,497 — — Other liabilities—interest rate derivatives 6,527 6,527 — 6,527 — — Accrued interest payable 6,623 6,623 6,623 — — — Fair Value Measurements at December 31, 2017 (unaudited, in thousands) Carrying Fair Value Quoted Prices in Significant Other Significant Investments 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)	9 Months Ended
	Sep. 30, 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 and nine months ended September 30, 2018: (unaudited, in thousands) Point of Revenue Recognition For the Three For the Nine Revenue Streams Trust fees Trust account fees Over time $ 4,006 $ 11,856 WesMark fees Over time 2,259 6,664 Total trust fees 6,265 18,520 Service charges on deposits Commercial banking fees Over time 563 1,406 Personal service charges At a point in time & over time 5,750 14,876 Total service charges on deposits 6,313 16,282 Net securities brokerage revenue Annuity commissions At a point in time 1,326 3,836 Equity and debt security trades At a point in time 116 304 Managed money Over time 173 477 Trail commissions Over time 221 698 Total net securities brokerage revenue 1,836 5,315 Allotment fees (1) At a point in time & over time 311 311 Electronic banking fees At a point in time 6,139 16,697 Mortgage banking income At a point in time 1,521 4,297 Net gain or loss on sale of other real estate owned At a point in time 150 641 (1) Allotment fees are included in other non-interest

Comprehensive Income_(Loss) (Ta

Comprehensive Income/(Loss) (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Components of Accumulated Other Comprehensive Income	The activity in accumulated other comprehensive income for the nine months ended September 30, 2018 and 2017 is as follows: Accumulated Other Comprehensive Income/(Loss) (1) (unaudited, in thousands) Defined Unrealized Available-for-Sale Unrealized Gains 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 — (33,013 ) — (33,013 ) Acquired FFKT Medical benefit plan 4,235 — — 4,235 Amounts reclassified from accumulated other comprehensive income 1,621 (9 ) (149 ) 1,463 Period change 5,856 (33,022 ) (149 ) (27,315 ) Adoption of Accounting Standard ASU 2016-01 (2) — (1,063 ) — (1,063 ) Balance at September 30, 2018 $ (12,770 ) $ (47,335 ) $ 232 $ (59,873 ) Balance at December 31, 2016 $ (17,758 ) $ (9,890 ) $ 522 $ (27,126 ) Other comprehensive income before reclassifications — 4,740 — 4,740 Amounts reclassified from accumulated other comprehensive income 1,679 35 (165 ) 1,549 Period change 1,679 4,775 (165 ) 6,289 Balance at September 30, 2017 $ (16,079 ) $ (5,115 ) $ 357 $ (20,837 ) (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 and nine months ended September 30, 2018 and 2017, respectively: Details about Accumulated Other Comprehensive Income Components (unaudited, in thousands) For the Three For the Nine Affected Line Item in the Statement of 2018 2017 2018 2017 Securities available-for-sale (1) Net securities gains/losses reclassified into earnings $ (11 ) $ — $ (11 ) $ 55 Net securities gains (Non-interest Related income tax benefit 2 — 2 (20 ) Provision for income taxes Net effect on accumulated other comprehensive income for the period (9 ) — (9 ) 35 Securities held-to-maturity (1) Amortization of unrealized gain transferred from available-for-sale (64 ) (66 ) (195 ) (256 ) Interest and dividends on securities (Interest and dividend income) Related income tax expense 15 24 46 91 Provision for income taxes Net effect on accumulated other comprehensive income for the period (49 ) (42 ) (149 ) (165 ) Defined benefit plans (2) Amortization of net loss and prior service costs 772 816 2,293 2,429 Employee benefits (Non-interest Related income tax benefit (177 ) (303 ) (672 ) (750 ) Provision for income taxes Net effect on accumulated other comprehensive income for the period 595 513 1,621 1,679 Total reclassifications for the period $ 537 $ 471 $ 1,463 $ 1,549 (1) For additional detail related to unrealized gains on securities and related amounts reclassified from accumulated other comprehensive income, see Note 4, “Securities.” (2) Included in the computation of net periodic pension cost. See Note 7, “Pension and Other Post Retirement Benefits” for additional detail.

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	9 Months Ended
	Sep. 30, 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: (unaudited, in thousands) September 30, December 31, Lines of credit $ 1,855,388 $ 1,452,697 Loans approved but not closed 349,173 245,644 Overdraft limits 154,221 126,671 Letters of credit 41,515 31,951 Contingent obligations and other guarantees 5,725 6,700

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Financial Information by Business Segment	Condensed financial information by business segment is presented below: (unaudited, in thousands) Community Trust and Consolidated For the Three Months ended September 30, 2018: Interest income $ 108,393 $ — $ 108,393 Interest expense 18,460 — 18,460 Net interest income 89,933 — 89,933 Provision for credit losses 1,035 — 1,035 Net interest income after provision for credit losses 88,898 — 88,898 Non-interest 19,959 6,265 26,224 Non-interest 72,378 3,742 76,120 Income before provision for income taxes 36,479 2,523 39,002 Provision for income taxes 5,986 530 6,516 Net income $ 30,493 $ 1,993 $ 32,486 For the Three Months ended September 30, 2017: Interest income $ 85,489 $ — $ 85,489 Interest expense 11,235 — 11,235 Net interest income 74,254 — 74,254 Provision for credit losses 2,516 — 2,516 Net interest income after provision for credit losses 71,738 — 71,738 Non-interest 15,541 5,358 20,899 Non-interest 52,355 3,399 55,754 Income before provision for income taxes 34,924 1,959 36,883 Provision for income taxes 9,744 783 10,527 Net income $ 25,180 $ 1,176 $ 26,356 For the Nine Months ended September 30, 2018: Interest income $ 293,596 $ — $ 293,596 Interest expense 48,127 — 48,127 Net interest income 245,469 — 245,469 Provision for credit losses 4,911 — 4,911 Net interest income after provision for credit losses 240,558 — 240,558 Non-interest 55,195 18,520 73,715 Non-interest 183,298 10,936 194,234 Income before provision for income taxes 112,455 7,584 120,039 Provision for income taxes 19,262 1,593 20,855 Net income $ 93,193 $ 5,991 $ 99,184 For the Nine Months ended September 30, 2017: Interest income $ 247,573 $ — $ 247,573 Interest expense 30,461 — 30,461 Net interest income 217,112 — 217,112 Provision for credit losses 7,610 — 7,610 Net interest income after provision for credit losses 209,502 — 209,502 Non-interest 48,833 17,073 65,906 Non-interest 156,102 9,921 166,023 Income before provision for income taxes 102,233 7,152 109,385 Provision for income taxes 27,940 2,861 30,801 Net income $ 74,293 $ 4,291 $ 78,584

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Feb. 28, 2016
Summary Of Significant Accounting Policies [Line Items]
Service cost component of defined benefit plan		$ 715	$ 650	$ 2,121	$ 1,929
Accounting Standards Update 2016-01 [Member]
Summary Of Significant Accounting Policies [Line Items]
Adjustment to retained earnings	$ 1,100
Accounting Standards Update 2016-02 [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cancellable operating leases						$ 15,000
Accounting Standards Update 2016-02 [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Non-cancellable operating leases						$ 20,000

Mergers and Acquisitions - Addi

Mergers and Acquisitions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Aug. 20, 2018	Apr. 05, 2018	Sep. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Total Assets			$ 12,599,479	$ 9,816,178
Portfolio loans, net of unearned income			7,726,423	$ 6,341,441
First Sentry Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Total Assets		$ 705,600
Portfolio loans, net of unearned income		448,100
Securities		142,903
Value of acquisition		$ 108,322
Closing stock price		$ 42.96
Number of shares issued for acquisition		2,498,761
Cash paid for acquisition		$ 975
Goodwill acquired		66,849
Purchase price allocation in core deposit intangible		$ 8,078
Merger related expense			5,500
Farmers Capital Bank Corporation [Member]
Business Acquisition [Line Items]
Total Assets	$ 1,600,000
Portfolio loans, net of unearned income	1,000,000
Securities	239,321
Value of acquisition	$ 428,901
Closing stock price	$ 49.40
Number of shares issued for acquisition	7,920,387
Cash paid for acquisition	$ 37,634
Goodwill acquired	225,092
Purchase price allocation in core deposit intangible	42,593
Merger related expense			$ 11,000
Farmers Capital Bank Corporation [Member] | Community Banking Segment [Member]
Business Acquisition [Line Items]
Goodwill acquired	225,100
Purchase price allocation in core deposit intangible	39,700
Farmers Capital Bank Corporation [Member] | Trust and Investment Services [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Purchase price allocation in core deposit intangible	$ 2,900

Mergers and Acquisitions - Summ

Mergers and Acquisitions - Summary of Purchase Price of Acquisition and Resulting Goodwill (Detail) - USD ($) $ in Thousands	Aug. 20, 2018	Apr. 05, 2018
First Sentry Bancshares, Inc. [Member]
Purchase Price:
Fair value of WesBanco shares issued		$ 107,347
Cash consideration for outstanding shares		975
Total purchase price		108,322
Fair value of:
Tangible assets acquired		610,443
Core deposit and other intangible assets acquired		8,078
Liabilities assumed		(664,172)
Net cash received in the acquisition		87,124
Fair value of net assets acquired		41,473
Goodwill recognized		$ 66,849
Farmers Capital Bank Corporation [Member]
Purchase Price:
Fair value of WesBanco shares issued	$ 391,267
Cash consideration for outstanding shares	37,634
Total purchase price	428,901
Fair value of:
Tangible assets acquired	1,360,951
Core deposit and other intangible assets acquired	42,593
Liabilities assumed	(1,429,874)
Net cash received in the acquisition	230,139
Fair value of net assets acquired	203,809
Goodwill recognized	$ 225,092

Mergers and Acquisitions - Allo

Mergers and Acquisitions - Allocation of Purchase Price of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Aug. 20, 2018	Jun. 30, 2018	Apr. 05, 2018
First Sentry Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Cash and due from banks				$ 87,124
Securities				142,903
Loans				448,075
Goodwill and other intangible assets				74,927
Accrued income and other assets				19,465
Total assets acquired				772,494
Liabilities assumed
Deposits				590,065
Borrowings				70,710
Accrued expenses and other liabilities				3,397
Total liabilities assumed				664,172
Fair value of net assets acquired				41,473
Net assets acquired				$ 108,322
Purchase Price Allocation Adjustment [Member]
Business Acquisition [Line Items]
Loans	$ (264)
Goodwill and other intangible assets	(159)
Accrued income and other assets	(6)
Liabilities assumed
Deposits	47
Accrued expenses and other liabilities	(154)
Fair value of net assets acquired	(630)
Increase in goodwill recognized	630
Goodwill recognized	$ 66,849		$ 66,219
Farmers Capital Bank Corporation [Member]
Business Acquisition [Line Items]
Cash and due from banks		$ 230,139
Securities		239,321
Loans		1,028,120
Goodwill and other intangible assets		267,685
Accrued income and other assets		93,510
Total assets acquired		1,858,775
Liabilities assumed
Deposits		1,330,328
Borrowings		71,780
Accrued expenses and other liabilities		27,766
Total liabilities assumed		1,429,874
Fair value of net assets acquired		203,809
Net assets acquired		$ 428,901

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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator for both basic and diluted earnings per common share:
Net income	$ 32,486	$ 26,356	$ 99,184	$ 78,584
Denominator:
Total average basic common shares outstanding	50,277,847	44,031,813	46,965,095	43,992,017
Effect of dilutive stock options and other stock compensation	154,265	55,068	142,734	67,452
Total diluted average common shares outstanding	50,432,112	44,086,881	47,107,829	44,059,469
Earnings per common share-basic	$ 0.65	$ 0.60	$ 2.11	$ 1.79
Earnings per common share-diluted	$ 0.64	$ 0.60	$ 2.11	$ 1.78

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Detail) - shares	Aug. 20, 2018	Apr. 05, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule Of Antidilutive Securities Included In Computation of Earnings Per Share [Line Items]
Shares contingently issuable under shareholder return plan					45,840
First Sentry Bancshares, Inc. [Member]
Schedule Of Antidilutive Securities Included In Computation of Earnings Per Share [Line Items]
Number of shares issued for acquisition		2,498,761
Number of shares granted to employees		9,465
Farmers Capital Bank Corporation [Member]
Schedule Of Antidilutive Securities Included In Computation of Earnings Per Share [Line Items]
Number of shares issued for acquisition	7,920,387
Number of shares granted to employees	18,685
Farmers Capital Bank Corporation [Member] | Treasury Stock [Member]
Schedule Of Antidilutive Securities Included In Computation of Earnings Per Share [Line Items]
Number of shares granted to employees	6,690
Restricted Stock [Member]
Schedule Of Antidilutive Securities Included In Computation of Earnings Per Share [Line Items]
Shares contingently issuable under shareholder return plan			17,081	4,502	17,081	4,502
Stock Option [Member]
Schedule Of Antidilutive Securities Included In Computation of Earnings Per Share [Line Items]
Securities excluded from computation of net income per diluted shares				117,550	117,600

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	Sep. 30, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	$ 2,069,660	$ 1,280,585
Available-for-sale, Gross Unrealized Gains	1,681	3,397
Available-for-sale, Gross Unrealized Losses	(63,109)	(22,117)
Available-for-sale, Estimated Fair Value	2,008,232	1,261,865
Held-to-maturity, Amortized Cost	1,025,538	1,009,500
Held-to-maturity, Gross Unrealized Gains	6,542	18,827
Held-to-maturity, Gross Unrealized Losses	(17,719)	(4,543)
Held-to-maturity securities, Fair value	1,014,361	1,023,784
Total securities, Amortized Cost	3,095,198	2,290,085
Total securities, Gross Unrealized Gains	8,223	22,224
Total securities, Gross Unrealized Losses	(80,828)	(26,660)
Total securities, Estimated Fair Value	3,022,593	2,285,649
U.S. Government Sponsored Entities and Agencies [Member]
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	154,054	72,425
Available-for-sale, Gross Unrealized Gains	17	24
Available-for-sale, Gross Unrealized Losses	(4,122)	(606)
Available-for-sale, Estimated Fair Value	149,949	71,843
Held-to-maturity, Amortized Cost	11,699	11,465
Held-to-maturity, Gross Unrealized Losses	(615)	(325)
Held-to-maturity securities, Fair value	11,084	11,140
Residential Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	1,500,563	954,115
Available-for-sale, Gross Unrealized Gains	44	214
Available-for-sale, Gross Unrealized Losses	(50,853)	(19,407)
Available-for-sale, Estimated Fair Value	1,449,754	934,922
Held-to-maturity, Amortized Cost	154,018	170,025
Held-to-maturity, Gross Unrealized Gains	103	544
Held-to-maturity, Gross Unrealized Losses	(6,788)	(2,609)
Held-to-maturity securities, Fair value	147,333	167,960
Obligations of State and Political Subdivisions [Member]
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	187,501	102,363
Available-for-sale, Gross Unrealized Gains	1,445	2,927
Available-for-sale, Gross Unrealized Losses	(2,295)	(460)
Available-for-sale, Estimated Fair Value	186,651	104,830
Held-to-maturity, Amortized Cost	826,514	794,655
Held-to-maturity, Gross Unrealized Gains	6,434	17,364
Held-to-maturity, Gross Unrealized Losses	(9,743)	(1,609)
Held-to-maturity securities, Fair value	823,205	810,410
Corporate Debt Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	43,259	35,234
Available-for-sale, Gross Unrealized Gains	160	228
Available-for-sale, Gross Unrealized Losses	(239)	(59)
Available-for-sale, Estimated Fair Value	43,180	35,403
Held-to-maturity, Amortized Cost	33,307	33,355
Held-to-maturity, Gross Unrealized Gains	5	919
Held-to-maturity, Gross Unrealized Losses	(573)
Held-to-maturity securities, Fair value	32,739	34,274
US Treasury Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	9,952
Available-for-sale, Gross Unrealized Losses	(15)
Available-for-sale, Estimated Fair Value	9,937
Commercial Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Debt and Equity Securities, FV-NI [Line Items]
Available-for-sale, Amortized Cost	174,331	116,448
Available-for-sale, Gross Unrealized Gains	15	4
Available-for-sale, Gross Unrealized Losses	(5,585)	(1,585)
Available-for-sale, Estimated Fair Value	$ 168,761	$ 114,867

Securities - Additional Informa

Securities - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018USD ($)Holdings	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)Holdings
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Maximum percentage of equity of one issuer	10.00%
Number of holdings greater than specified percentage of equity | Holdings	0		0
Equities securities	$ 12,784,000		$ 13,457,000
Securities with aggregate fair values	1,900,000,000		1,400,000,000
Net unrealized losses on available-for-sale debt securities included in AOCI	47,300,000		13,300,000
Sales of available-for-sale debt securities	82,100,000	$ 7,800,000
Impairment loss relating to securities	0
Federal home loan bank stock, Total	53,800,000		$ 45,900,000
Grantor Trusts [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Equities securities	$ 8,500,000

Securities - Schedule of Fair_2

Securities - Schedule of Fair Value of Available-for-Sale and Held-to-Maturity Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 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	$ 37,718
Total available-for-sale securities, One to Five Years	88,470
Total available-for-sale securities, Five to Ten Years	96,768
Total available-for-sale securities, After Ten Years	66,730
Total available-for-sale securities, Mortgage-backed	1,718,546
Available-for-sale, Estimated Fair Value	2,008,232	$ 1,261,865
Total held-to-maturity securities, One Year or less	6,149
Total held-to-maturity securities, One to Five Years	146,158
Total held-to-maturity securities, Five to Ten Years	413,065
Total held-to-maturity securities, After Ten Years	290,572
Total held-to-maturity securities, Mortgage-backed	158,417
Held-to-maturity securities, Fair value	1,014,361	1,023,784
Total, One Year or less	43,867
Total, One to Five Years	234,628
Total, Five to Ten Years	509,833
Total, After Ten Years, Fair value	357,302
Total, Mortgage-backed	1,876,963
Total, Fair value	3,022,593	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	9,937
Available-for-sale, Estimated Fair Value	9,937
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	10,479
Total available-for-sale securities, One to Five Years	6,260
Total available-for-sale securities, Five to Ten Years	17,881
Total available-for-sale securities, After Ten Years	15,298
Total available-for-sale securities, Mortgage-backed	100,031
Available-for-sale, Estimated Fair Value	149,949	71,843
Total held-to-maturity securities, Mortgage-backed	11,084
Held-to-maturity securities, Fair value	11,084	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	1,449,754
Available-for-sale, Estimated Fair Value	1,449,754	934,922
Total held-to-maturity securities, Mortgage-backed	147,333
Held-to-maturity securities, Fair value	147,333	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	168,761
Available-for-sale, Estimated Fair Value	168,761	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	9,288
Total available-for-sale securities, One to Five Years	48,959
Total available-for-sale securities, Five to Ten Years	76,972
Total available-for-sale securities, After Ten Years	51,432
Available-for-sale, Estimated Fair Value	186,651	104,830
Total held-to-maturity securities, One Year or less	6,149
Total held-to-maturity securities, One to Five Years	138,709
Total held-to-maturity securities, Five to Ten Years	387,775
Total held-to-maturity securities, After Ten Years	290,572
Held-to-maturity securities, Fair value	823,205	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	8,014
Total available-for-sale securities, One to Five Years	33,251
Total available-for-sale securities, Five to Ten Years	1,915
Available-for-sale, Estimated Fair Value	43,180	35,403
Total held-to-maturity securities, One to Five Years	7,449
Total held-to-maturity securities, Five to Ten Years	25,290
Held-to-maturity securities, Fair value	$ 32,739	$ 34,274

Securities - Schedule of Fair_3

Securities - Schedule of Fair Value of Available-for-Sale and Held-to-Maturity Debt Securities by Contractual Maturity (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost and Fair Value Debt Securities [Abstract]
Held-to-maturity, Amortized Cost	$ 1,025,538	$ 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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Available-for-Sale Securities, Gross Unrealized Gain (Loss) [Line Items]
Net securities gains	$ 84	$ 6	$ 403	$ 511
Debt Securities [Member]
Available-for-Sale Securities, Gross Unrealized Gain (Loss) [Line Items]
Gross realized gains	88	29	100	603
Gross realized losses	(13)	(23)	(31)	(92)
Net gains on debt securities	75	$ 6	69	$ 511
Equity Securities [Member]
Available-for-Sale Securities, Gross Unrealized Gain (Loss) [Line Items]
Unrealized gains recognized on securities still held	11		330
Net realized (losses) gains recognized on securities sold	(2)		4
Net gains on equity securities	$ 9		$ 334

Securities - Schedule of Unreal

Securities - Schedule of Unrealized Losses on Debt Securities (Detail) $ in Thousands	Sep. 30, 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	$ 9,937
Less than 12 months, Unrealized Losses	$ (15)
Less than 12 months, Number of Securities | Security	1
Fair Value, Total	$ 9,937
Unrealized Losses, Total	$ (15)
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	$ 93,881	$ 24,776
Less than 12 months, Unrealized Losses	$ (2,264)	$ (160)
Less than 12 months, Number of Securities | Security	38	4
12 months or more, Fair Value	$ 60,410	$ 42,248
12 months or more, Unrealized Losses	$ (2,473)	$ (771)
12 months or more, Number of Securities | Security	11	8
Fair Value, Total	$ 154,291	$ 67,024
Unrealized Losses, Total	$ (4,737)	$ (931)
Number of Securities Total | Security	49	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	$ 759,415	$ 423,794
Less than 12 months, Unrealized Losses	$ (13,670)	$ (5,039)
Less than 12 months, Number of Securities | Security	188	87
12 months or more, Fair Value	$ 822,774	$ 637,461
12 months or more, Unrealized Losses	$ (43,971)	$ (16,977)
12 months or more, Number of Securities | Security	260	193
Fair Value, Total	$ 1,582,189	$ 1,061,255
Unrealized Losses, Total	$ (57,641)	$ (22,016)
Number of Securities Total | Security	448	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	$ 79,056	$ 79,061
Less than 12 months, Unrealized Losses	$ (1,239)	$ (1,089)
Less than 12 months, Number of Securities | Security	15	10
12 months or more, Fair Value	$ 86,703	$ 27,852
12 months or more, Unrealized Losses	$ (4,346)	$ (496)
12 months or more, Number of Securities | Security	11	6
Fair Value, Total	$ 165,759	$ 106,913
Unrealized Losses, Total	$ (5,585)	$ (1,585)
Number of Securities Total | Security	26	16
Obligations of State and Political Subdivisions [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 493,252	$ 132,831
Less than 12 months, Unrealized Losses	$ (7,866)	$ (852)
Less than 12 months, Number of Securities | Security	855	210
12 months or more, Fair Value	$ 120,843	$ 77,554
12 months or more, Unrealized Losses	$ (4,172)	$ (1,217)
12 months or more, Number of Securities | Security	236	160
Fair Value, Total	$ 614,095	$ 210,385
Unrealized Losses, Total	$ (12,038)	$ (2,069)
Number of Securities Total | Security	1,091	370
Corporate Debt Securities [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 42,816	$ 4,015
Less than 12 months, Unrealized Losses	$ (738)	$ (19)
Less than 12 months, Number of Securities | Security	17	1
12 months or more, Fair Value	$ 1,915	$ 1,948
12 months or more, Unrealized Losses	$ (74)	$ (40)
12 months or more, Number of Securities | Security	1	1
Fair Value, Total	$ 44,731	$ 5,963
Unrealized Losses, Total	$ (812)	$ (59)
Number of Securities Total | Security	18	2
Total Temporarily Impaired Securities [Member]
Net Unrealized Gains And Losses On Investments [Line Items]
Less than 12 months, Fair Value	$ 1,478,357	$ 664,477
Less than 12 months, Unrealized Losses	$ (25,792)	$ (7,159)
Less than 12 months, Number of Securities | Security	1,114	312
12 months or more, Fair Value	$ 1,092,645	$ 787,063
12 months or more, Unrealized Losses	$ (55,036)	$ (19,501)
12 months or more, Number of Securities | Security	519	368
Fair Value, Total	$ 2,571,002	$ 1,451,540
Unrealized Losses, Total	$ (80,828)	$ (26,660)
Number of Securities Total | Security	1,633	680

Loans and the Allowance for C_3

Loans and the Allowance for Credit Losses - Additional Information (Detail)	Aug. 20, 2018USD ($)	Apr. 05, 2018USD ($)	Jun. 30, 2018USD ($)	Sep. 30, 2018USD ($)Contract	Dec. 31, 2017USD ($)Contract
Financing Receivable, Recorded Investment [Line Items]
Deferred loan (costs) and fees				$ 2,800,000	$ 1,600,000
Unamortized discount on purchased loans from acquisitions				54,300,000	21,900,000
Aggregate amount of residential real estate, home equity and consumer loans classified as substandard				20,600,000	22,800,000
Internally assigned loan grades to residential real estate, home equity and consumer loans				2,200,000	2,500,000
Loans acquired with deteriorated credit quality				$ 11,041,000	$ 8,074,000
Number of restructured contracts greater than $0 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				$ 200,000	100,000
Other real estate owned				6,836,000	5,195,000
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans acquired with deteriorated credit quality				777,000	783,000
Maximum [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Annual sales of borrowers				100,000,000
First Sentry Bancshares, Inc. [Member]
Financing Receivable, Recorded Investment [Line Items]
Unamortized discount on purchased loans from acquisitions				6,700,000
Portfolio loans, net of unearned income		$ 465,900,000
Fair value of acquired loans		448,075,000
Fair market value adjustment of acquired loans		440,100,000
Fair market value adjustment of acquired loans		9,700,000
Loans acquired with deteriorated credit quality		4,100,000		1,700,000
Loans acquired with deteriorated credit quality, fair value		2,000,000
Loans acquired with deteriorated credit quality outstanding customer balance				3,800,000
Acquired impaired loans allowances for loan losses				0
Acquired loans, sold book value			$ 17,700,000	4,000,000
Acquired loans, transferred to loans held for sale fair value				2,800,000
Acquired loans, sold			$ 12,900,000
First Sentry Bancshares, Inc. [Member] | Cost Recovery Method [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans acquired with deteriorated credit quality, fair value		$ 700,000
Farmers Capital Bank Corporation [Member]
Financing Receivable, Recorded Investment [Line Items]
Unamortized discount on purchased loans from acquisitions				25,900,000
Portfolio loans, net of unearned income	$ 1,064,800,000
Fair value of acquired loans	1,028,120,000
Fair market value adjustment of acquired loans	1,016,900,000
Fair market value adjustment of acquired loans	26,400,000
Loans acquired with deteriorated credit quality	2,700,000			2,100,000
Loans acquired with deteriorated credit quality, fair value	$ 2,400,000
Loans acquired with deteriorated credit quality outstanding customer balance				2,400,000
Acquired impaired loans allowances for loan losses				0
Acquired loans, sold book value				45,200,000
Acquired loans, transferred to loans held for sale fair value				35,200,000
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans acquired with deteriorated credit quality				2,930,000	714,000
Other real estate owned				700,000	1,500,000
Foreclosure proceedings in process on residential real estate loans				$ 6,000,000	$ 3,500,000

Loans and the Allowance for C_4

Loans and the Allowance for Credit Losses - Schedule of Recorded Investment in Loans by Category (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 7,726,423	$ 6,341,441
Loans held for sale	55,913	20,320
Total loans	7,782,336	6,361,761
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	538,922	392,597
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	3,367,299	2,601,851
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,292,073	1,125,327
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	3,906,221	2,994,448
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	1,598,477	1,353,301
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	325,546	339,169
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total portfolio loans	$ 604,106	$ 529,196

Loans and the Allowance for C_5

Loans and the Allowance for Credit Losses - Summary of Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 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			4,801	7,534
Provision for loan commitments			110	76
Total provision for credit losses	$ 1,035	$ 2,516	4,911	7,610
Charge-offs			(6,751)	(9,000)
Recoveries			5,568	3,279
Net charge-offs			(1,183)	(5,721)
Allowance for loan losses, ending balance	48,902	45,487	48,902	45,487
Allowance for loan commitments, ending balance	684	647	684	647
Total ending allowance for credit losses	49,586	46,134	49,586	46,134
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			789	415
Provision for loan commitments			67	(18)
Total provision for credit losses			856	397
Charge-offs			(137)
Recoveries			400	89
Net charge-offs			263	89
Allowance for loan losses, ending balance	4,169	4,852	4,169	4,852
Allowance for loan commitments, ending balance	186	133	186	133
Total ending allowance for credit losses	4,355	4,985	4,355	4,985
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			(721)	1,619
Provision for loan commitments			(3)	4
Total provision for credit losses			(724)	1,623
Charge-offs			(719)	(1,752)
Recoveries			1,098	492
Net charge-offs			379	(1,260)
Allowance for loan losses, ending balance	20,824	18,987	20,824	18,987
Allowance for loan commitments, ending balance	23	21	23	21
Total ending allowance for credit losses	20,847	19,008	20,847	19,008
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			2,538	2,842
Provision for loan commitments			32	45
Total provision for credit losses			2,570	2,887
Charge-offs			(871)	(2,255)
Recoveries			970	649
Net charge-offs			99	(1,606)
Allowance for loan losses, ending balance	12,051	9,648	12,051	9,648
Allowance for loan commitments, ending balance	205	233	205	233
Total ending allowance for credit losses	12,256	9,881	12,256	9,881
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			840	680
Total provision for credit losses			840	680
Charge-offs			(941)	(947)
Recoveries			277	267
Net charge-offs			(664)	(680)
Allowance for loan losses, ending balance	997	760	997	760
Total ending allowance for credit losses	997	760	997	760
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			1,106	(203)
Provision for loan commitments			2
Total provision for credit losses			1,108	(203)
Charge-offs			(873)	(797)
Recoveries			336	266
Net charge-offs			(537)	(531)
Allowance for loan losses, ending balance	3,775	3,372	3,775	3,372
Allowance for loan commitments, ending balance	9	9	9	9
Total ending allowance for credit losses	3,784	3,381	3,784	3,381
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			541	922
Provision for loan commitments			3	(4)
Total provision for credit losses			544	918
Charge-offs			(2,465)	(2,877)
Recoveries			1,657	1,336
Net charge-offs			(808)	(1,541)
Allowance for loan losses, ending balance	2,796	3,379	2,796	3,379
Allowance for loan commitments, ending balance	40	40	40	40
Total ending allowance for credit losses	2,836	3,419	2,836	3,419
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			(292)	1,259
Provision for loan commitments			9	49
Total provision for credit losses			(283)	1,308
Charge-offs			(745)	(372)
Recoveries			830	180
Net charge-offs			85	(192)
Allowance for loan losses, ending balance	4,290	4,489	4,290	4,489
Allowance for loan commitments, ending balance	221	211	221	211
Total ending allowance for credit losses	$ 4,511	$ 4,700	$ 4,511	$ 4,700

Loans and the Allowance for C_6

Loans and the Allowance for Credit Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans individually evaluated for impairment		$ 388
Allowance for loans collectively evaluated for impairment	$ 48,902	44,896
Allowance for loan commitments	684	574	$ 647	$ 571
Total allowance for credit losses	49,586	45,858	46,134	44,245
Individually evaluated for impairment		3,344
Collectively evaluated for impairment	7,715,382	6,330,023
Acquired with deteriorated credit quality	11,041	8,074
Total loans	7,726,423	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	4,169	3,117
Allowance for loan commitments	186	119	133	151
Total allowance for credit losses	4,355	3,236	4,985	4,499
Collectively evaluated for impairment	537,699	391,140
Acquired with deteriorated credit quality	1,223	1,457
Total loans	538,922	392,597
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans individually evaluated for impairment		388
Allowance for loans collectively evaluated for impairment	20,824	20,778
Allowance for loan commitments	23	26	21	17
Total allowance for credit losses	20,847	21,192	19,008	18,645
Individually evaluated for impairment		3,344
Collectively evaluated for impairment	3,361,315	2,593,393
Acquired with deteriorated credit quality	5,984	5,114
Total loans	3,367,299	2,601,851
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	12,051	9,414
Allowance for loan commitments	205	173	233	188
Total allowance for credit losses	12,256	9,587	9,881	8,600
Collectively evaluated for impairment	1,291,296	1,124,544
Acquired with deteriorated credit quality	777	783
Total loans	1,292,073	1,125,327
Deposit Overdraft [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	997	821
Total allowance for credit losses	997	821	760	760
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	3,775	3,206
Allowance for loan commitments	9	7	9	9
Total allowance for credit losses	3,784	3,213	3,381	4,115
Collectively evaluated for impairment	1,595,547	1,352,587
Acquired with deteriorated credit quality	2,930	714
Total loans	1,598,477	1,353,301
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	2,796	3,063
Allowance for loan commitments	40	37	40	44
Total allowance for credit losses	2,836	3,100	3,419	4,042
Collectively evaluated for impairment	325,419	339,163
Acquired with deteriorated credit quality	127	6
Total loans	325,546	339,169
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loans collectively evaluated for impairment	4,290	4,497
Allowance for loan commitments	221	212	211	162
Total allowance for credit losses	4,511	4,709	$ 4,700	$ 3,584
Collectively evaluated for impairment	604,106	529,196
Total loans	$ 604,106	$ 529,196

Loans and the Allowance for C_7

Loans and the Allowance for Credit Losses - Allowance for Credit Losses and Recorded Investments in Loans (Parenthetical) (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Troubled debt restructuring threshold	$ 1	$ 1

Loans and the Allowance for C_8

Loans and the Allowance for Credit Losses - Summary of Commercial Loans by Risk Grade (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Summary of commercial loans by risk grade
Commercial loans	$ 7,677,521	$ 6,296,157
Commercial Portfolio Segment [Member]
Summary of commercial loans by risk grade
Commercial loans	5,198,294	4,119,775
Commercial Portfolio Segment [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	5,120,487	4,045,825
Commercial Portfolio Segment [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	46,370	36,092
Commercial Portfolio Segment [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	31,437	37,858
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member]
Summary of commercial loans by risk grade
Commercial loans	538,922	392,597
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	533,982	386,753
Commercial Portfolio Segment [Member] | Commercial Real Estate - Land and Construction [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	2,909	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	2,031	2,860
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member]
Summary of commercial loans by risk grade
Commercial loans	3,367,299	2,601,851
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	3,314,324	2,548,805
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	31,399	25,673
Commercial Portfolio Segment [Member] | Commercial Real Estate - Improved Property [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	21,576	27,373
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Summary of commercial loans by risk grade
Commercial loans	1,292,073	1,125,327
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Pass [Member]
Summary of commercial loans by risk grade
Commercial loans	1,272,181	1,110,267
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Criticized [Member]
Summary of commercial loans by risk grade
Commercial loans	12,062	7,435
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Classified - Substandard [Member]
Summary of commercial loans by risk grade
Commercial loans	$ 7,830	$ 7,625

Loans and the Allowance for C_9

Loans and the Allowance for Credit Losses - Summary of Changes in Accretable Yield for Loans Acquired with Deteriorated Credit Quality (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 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	695
Reduction due to change in projected cash flows	(86)
Reclass from non-accretable difference	6,287	1,490
Transfers out		(216)
Accretion	(902)	(1,384)
Balance at end of period	$ 7,718	$ 1,607

Loans and the Allowance for _10

Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Current	$ 7,681,491	$ 6,299,397
Total Past Due	44,932	42,044
Total loans	7,726,423	6,341,441
90 Days or More Past Due and Accruing	2,451	2,726
Loans held for sale, current	55,913	20,320
Loans held for sale	55,913	20,320
Total loans, current	7,737,404	6,319,717
Total loans	7,782,336	6,361,761
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	596,477	522,584
Total Past Due	7,629	6,612
Total loans	604,106	529,196
90 Days or More Past Due and Accruing	646	742
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	3,896,064	2,981,893
Total Past Due	10,157	12,555
Total loans	3,906,221	2,994,448
90 Days or More Past Due and Accruing	88	243
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	1,579,164	1,338,240
Total Past Due	19,313	15,061
Total loans	1,598,477	1,353,301
90 Days or More Past Due and Accruing	1,225	1,113
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	322,093	334,723
Total Past Due	3,453	4,446
Total loans	325,546	339,169
90 Days or More Past Due and Accruing	378	608
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	538,181	392,189
Total Past Due	741	408
Total loans	538,922	392,597
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	3,357,883	2,589,704
Total Past Due	9,416	12,147
Total loans	3,367,299	2,601,851
90 Days or More Past Due and Accruing	88	243
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	1,287,693	1,121,957
Total Past Due	4,380	3,370
Total loans	1,292,073	1,125,327
90 Days or More Past Due and Accruing	114	20
Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	7,480	9,195
Total Past Due	23,794	27,630
Total loans	31,274	36,825
TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	5,667	6,055
Total Past Due	671	516
Total loans	6,338	6,571
Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Current	13,147	15,250
Total Past Due	24,465	28,146
Total loans	37,612	43,396
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	16,338	10,034
30-59 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,871	2,135
30-59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,300	374
30-59 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	8,100	4,487
30-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,291	2,466
30-59 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	643
30-59 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,657	374
30-59 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	776	572
30-59 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,653	1,782
30-59 Days Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	314	348
30-59 Days Past Due [Member] | Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,967	2,130
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	5,227	5,469
60-89 Days Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,002	683
60-89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	450	1,372
60-89 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	2,708	2,376
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	605	842
60-89 Days Past Due [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	98	172
60-89 Days Past Due [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	352	1,200
60-89 Days Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	462	196
60-89 Days Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,225	2,033
60-89 Days Past Due [Member] | TDRs Accruing Interest [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	357	168
60-89 Days Past Due [Member] | Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	1,582	2,201
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	23,367	26,541
90 Days or More Past Due [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	3,756	3,794
90 Days or More Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	7,407	10,809
90 Days or More Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	8,505	8,198
90 Days or More Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	557	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		236
90 Days or More Past Due [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	7,407	10,573
90 Days or More Past Due [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	3,142	2,602
90 Days or More Past Due [Member] | Non-Accrual Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	20,916	23,815
90 Days or More Past Due [Member] | Total Impaired [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Past Due	$ 20,916	$ 23,815

Loans and the Allowance for _11

Loans and the Allowance for Credit Losses - Summary of Age Analysis of Loan Categories (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Past due loans excluded TDRs past due and accruing	90 days

Loans and the Allowance for _12

Loans and the Allowance for Credit Losses - Summary of Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	$ 46,158		$ 46,158		$ 50,124
Total impaired loans, Unpaid principal balance	46,158		46,158		52,229
Recorded Investment, With no specific allowance recorded	37,612		37,612		41,291
Total impaired loans, Recorded investment	37,612		37,612		43,396
Unpaid Principal Balance, With a specific allowance recorded					2,105
Recorded Investment, With a specific allowance recorded					2,105
Related Allowance, With a specific allowance recorded					388
Average recorded investment, with no related specific allowance	37,542	$ 37,452	38,225	$ 37,432
Interest income recognized, With no related specific allowance	99	96	614	617
Average recorded investment, With a specific allowance recorded		5,137	1,052	5,350
Interest income recognized, With a specific allowance recorded	0	0	0	0
Total impaired loans, Average recorded investment	37,542	42,589	39,277	42,782
Total impaired loans, Interest income recognized	99	96	614	617
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	21,226		21,226		20,821
Recorded Investment, With no specific allowance recorded	18,944		18,944		18,982
Average recorded investment, with no related specific allowance	18,336	17,039	18,207	17,743
Interest income recognized, With no related specific allowance	68	57	195	192
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	857		857		1,084
Recorded Investment, With no specific allowance recorded	685		685		952
Average recorded investment, with no related specific allowance	692	731	776	746
Interest income recognized, With no related specific allowance	3	2	8	5
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	5,550		5,550		5,833
Recorded Investment, With no specific allowance recorded	4,728		4,728		5,169
Average recorded investment, with no related specific allowance	4,924	4,727	4,997	4,456
Interest income recognized, With no related specific allowance	8	4	19	14
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded					412
Recorded Investment, With no specific allowance recorded					239
Average recorded investment, with no related specific allowance		444	260	516
Interest income recognized, With a specific allowance recorded	0	0	0	0
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	14,639		14,639		18,229
Recorded Investment, With no specific allowance recorded	9,928		9,928		12,863
Unpaid Principal Balance, With a specific allowance recorded					2,105
Recorded Investment, With a specific allowance recorded					2,105
Related Allowance, With a specific allowance recorded					388
Average recorded investment, with no related specific allowance	10,409	10,923	11,000	10,271
Interest income recognized, With no related specific allowance	15	31	383	400
Average recorded investment, With a specific allowance recorded		5,137	1,052	5,032
Interest income recognized, With a specific allowance recorded	0	0	0	0
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance, With no specific allowance recorded	3,886		3,886		3,745
Recorded Investment, With no specific allowance recorded	3,327		3,327		$ 3,086
Average recorded investment, with no related specific allowance	3,181	3,588	2,985	3,700
Interest income recognized, With no related specific allowance	5	2	9	6
Average recorded investment, With a specific allowance recorded				318
Interest income recognized, With a specific allowance recorded	$ 0	$ 0	$ 0	$ 0

Loans and the Allowance for _13

Loans and the Allowance for Credit Losses - Recorded Investment in Non-Accrual Loans and TDRs (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Non-accrual loans	$ 31,274	$ 36,825
TDRs	8,374	9,436
Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	6,338	6,571
Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	2,036	2,865
Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans		239
TDRs		3
Commercial Real Estate - Land and Construction [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs		3
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	8,757	13,318
TDRs	1,811	2,078
Commercial Real Estate - Improved Property [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	1,171	1,650
Commercial Real Estate - Improved Property [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	640	428
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	3,165	2,958
TDRs	162	225
Commercial and Industrial [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	162	128
Commercial and Industrial [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs		97
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	4,283	4,762
TDRs	612	744
Home Equity [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	445	407
Home Equity [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	167	337
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	8,757	13,557
TDRs	1,811	2,081
Commercial Real Estate [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	1,171	1,650
Commercial Real Estate [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	640	431
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	14,475	14,661
TDRs	5,651	6,201
Residential Real Estate [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	4,469	4,321
Residential Real Estate [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	1,182	1,880
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	594	887
TDRs	138	185
Consumer [Member] | Accruing TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	91	65
Consumer [Member] | Non-Accrual TDRs [Member]
Financing Receivable, Impaired [Line Items]
TDRs	$ 47	$ 120

Loans and the Allowance for _14

Loans and the Allowance for Credit Losses - Recorded Investment in Non-Accrual Loans and TDRs (Parenthetical) (Detail)	Sep. 30, 2018USD ($)Borrowers	Dec. 31, 2017USD ($)Borrowers
Receivables [Abstract]
Number of borrowers with loans greater than one million | Borrowers	1	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	$ 3,400,000	$ 6,800,000

Loans and the Allowance for _15

Loans and the Allowance for Credit Losses - Loans Identified as TDRs (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)Contract	Sep. 30, 2017USD ($)Contract	Sep. 30, 2018USD ($)Contract	Sep. 30, 2017USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract	1	4	11	11
Pre-Modification Outstanding Recorded Investment	$ 19	$ 291	$ 298	$ 459
Post-Modification Outstanding Recorded Investment	$ 18	$ 279	$ 255	$ 426
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract		1		1
Pre-Modification Outstanding Recorded Investment		$ 190		$ 190
Post-Modification Outstanding Recorded Investment		$ 185		$ 185
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract			1	1
Pre-Modification Outstanding Recorded Investment			$ 10	$ 64
Post-Modification Outstanding Recorded Investment			$ 8	$ 59
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract		1		1
Pre-Modification Outstanding Recorded Investment		$ 190		$ 190
Post-Modification Outstanding Recorded Investment		$ 185		$ 185
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract			5	2
Pre-Modification Outstanding Recorded Investment			$ 203	$ 22
Post-Modification Outstanding Recorded Investment			$ 176	$ 17
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract	1	1	4	4
Pre-Modification Outstanding Recorded Investment	$ 19	$ 7	$ 65	$ 42
Post-Modification Outstanding Recorded Investment	$ 18	$ 6	$ 52	$ 33
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications | Contract		2	1	3
Pre-Modification Outstanding Recorded Investment		$ 94	$ 20	$ 141
Post-Modification Outstanding Recorded Investment		$ 88	$ 19	$ 132

Loans and the Allowance for _16

Loans and the Allowance for Credit Losses - TDRs Defaulted Later Restructured (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)Defaults	Sep. 30, 2017USD ($)Defaults
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults	3	2
Recorded Investment | $	$ 178	$ 14
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults	2	1
Recorded Investment | $	$ 172	$ 7
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults		1
Recorded Investment | $		$ 7
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Defaults | Defaults	1
Recorded Investment | $	$ 6

Loans and the Allowance for _17

Loans and the Allowance for Credit Losses - Summary of Other Real Estate Owned and Repossessed Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Receivables [Abstract]
Other real estate owned	$ 6,836	$ 5,195
Repossessed assets	41	102
Total other real estate owned and repossessed assets	$ 6,877	$ 5,297

Derivatives and Hedging Activ_3

Derivatives and Hedging Activities - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)Derivative	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Derivative	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)Derivative
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Aggregate notional amount	$ 234,400,000		$ 234,400,000		$ 298,200,000
Net gain (loss) on change in fair value	(273,000)	$ (32,000)	480,000	$ (212,000)
Collateral posted with market value on liability positions with credit risk-related contingent features	$ 3,700,000		$ 3,700,000
Interest Rate Swaps [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate swaps | Derivative	42		42		39
Net gain (loss) on change in fair value			$ (100,000)	(300,000)
Income (loss) on derivative instrument not designated hedges			$ 1,400,000	$ 1,200,000

Derivatives and Hedging Activ_4

Derivatives and Hedging Activities - Summary of Fair Values of Derivative Instruments on Balance Sheets (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	$ 234,400,000	$ 298,200,000
Asset Derivatives	6,631,000	7,400,000
Liability Derivatives	6,527,000	7,368,000
Interest Rate Swaps [Member] | Loan Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	234,363,000	298,223,000
Asset Derivatives	6,451,000	7,351,000
Liability Derivatives	6,527,000	7,345,000
Interest Rate Loan Commitments [Member] | Other Contract [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	27,795,000	20,319,000
Asset Derivatives	32,000	49,000
Forward TBA Contracts [Member] | Other Contract [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	32,000,000	31,750,000
Asset Derivatives	$ 148,000
Liability Derivatives		$ 23,000

Derivatives and Hedging Activ_5

Derivatives and Hedging Activities - Summary of Effect of Derivative Instruments on Income Statement (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	$ (273)	$ (32)	$ 480	$ (212)
Interest Rate Swaps [Member] | Other Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	(293)	$ (32)	(82)	(335)
Interest Rate Loan Commitments [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	(111)		32	$ 123
Forward TBA Contracts [Member] | Mortgage Banking Income [Member]
Derivatives, Fair Value [Line Items]
Total gain (loss) on derivative financial instruments	$ 131		$ 530

Pension Plan - Components of Ne

Pension Plan - Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost - benefits earned during year	$ 715	$ 650	$ 2,121	$ 1,929
Interest cost on projected benefit obligation	1,242	1,107	3,684	3,287
Expected return on plan assets	(2,416)	(1,928)	(7,169)	(5,721)
Amortization of prior service cost	6	7	19	19
Amortization of net loss	766	812	2,274	2,409
Net periodic pension cost	$ 313	$ 648	$ 929	$ 1,923

Pension Plan - Additional Infor

Pension Plan - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Aug. 20, 2018	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum required pension plan contribution	$ 5,100,000		$ 5,100,000
Voluntary contribution			56,900,000
Available credit balance						$ 2,500,000
Net periodic pension income	313,000	$ 648,000	929,000	$ 1,923,000
Expected return on plan assets	2,416,000	1,928,000	7,169,000	5,721,000
Interest cost on projected benefit obligation	1,242,000	$ 1,107,000	3,684,000	$ 3,287,000
Farmers Capital Bank Corporation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Postretirement medical benefit plan	9,500,000		$ 9,500,000		$ 15,000,000
Life of the plan			17 years
Defined benefit plan, Unrealized gain			$ 5,500,000
Pentegra Defined Benefit Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum required pension plan contribution	0		0
Voluntary contribution			200,000
Net periodic pension income	100,000		200,000
Expected return on plan assets	200,000		500,000
Interest cost on projected benefit obligation	$ 100,000		$ 300,000

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	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	$ 12,784	$ 13,457
Total debt securities - available-for-sale	2,008,232	1,261,865
Loans held for sale	55,913	20,320
Other real estate owned and repossessed assets	6,877	5,297
Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	12,784	13,457
Total debt securities - available-for-sale	2,008,232	1,261,865
Loans held for sale	55,913	20,320
Other assets - interest rate derivatives agreements	6,451	7,351
Total assets recurring fair value measurements	2,083,380	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	6,527	7,345
Total liabilities recurring fair value measurements	6,527	7,345
Impaired loans		1,717
Other real estate owned and repossessed assets	6,877	5,297
Total assets recurring fair value measurements	6,877	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	9,937
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	9,937
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	149,949	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	149,949	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	1,449,754	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	1,449,754	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	168,761	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	168,761	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	186,651	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	186,651	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	43,180	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	43,180	35,403
Investments Measured at Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		2,066
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	0	2,066
Total debt securities - available-for-sale	0	0
Loans held for sale	0	0
Other assets - interest rate derivatives agreements	0	0
Total assets recurring fair value measurements	0	2,066
Investments Measured at Net Asset Value [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	0	0
Total liabilities recurring fair value measurements	0	0
Impaired loans	0	0
Other real estate owned and repossessed assets	0	0
Total assets recurring fair value measurements	0	0
Investments Measured at Net Asset Value [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	0
Investments Measured at Net Asset Value [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	0	0
Investments Measured at Net Asset Value [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	0	0
Investments Measured at Net Asset Value [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	0	0
Investments Measured at Net Asset Value [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	0	0
Investments Measured at Net Asset Value [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	0	0
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	12,784	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	12,784	11,391
Total debt securities - available-for-sale	0	0
Loans held for sale	0	0
Other assets - interest rate derivatives agreements	0	0
Total assets recurring fair value measurements	12,784	11,391
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0	0
Total liabilities recurring fair value measurements	0	0
Impaired loans	0	0
Other real estate owned and repossessed assets	0	0
Total assets recurring fair value measurements	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [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	0	0
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	6,527	7,345
Total debt securities - available-for-sale	2,006,706	1,261,865
Loans held for sale	55,913	20,320
Other assets - interest rate derivatives agreements	6,451	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]
Equity securities	0	0
Total debt securities - available-for-sale	2,006,706	1,261,865
Loans held for sale	55,913	20,320
Other assets - interest rate derivatives agreements	6,451	7,351
Total assets recurring fair value measurements	2,069,070	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	6,527	7,345
Total liabilities recurring fair value measurements	6,527	7,345
Impaired loans	0	0
Other real estate owned and repossessed assets	0	0
Total assets recurring fair value measurements	0	0
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	9,937
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	149,949	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	1,449,754	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	168,761	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	185,125	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	43,180	35,403
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities - available-for-sale	1,526
Significant Unobservable Inputs (Level 3) [Member] | Recurring Fair Value Measurements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	0	0
Total debt securities - available-for-sale	1,526	0
Loans held for sale	0	0
Other assets - interest rate derivatives agreements	0	0
Total assets recurring fair value measurements	1,526	0
Significant Unobservable Inputs (Level 3) [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	0	0
Total liabilities recurring fair value measurements	0	0
Impaired loans	0	1,717
Other real estate owned and repossessed assets	6,877	5,297
Total assets recurring fair value measurements	6,877	7,014
Significant Unobservable Inputs (Level 3) [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	0
Significant Unobservable Inputs (Level 3) [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	0	0
Significant Unobservable Inputs (Level 3) [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	0	0
Significant Unobservable Inputs (Level 3) [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	0	0
Significant Unobservable Inputs (Level 3) [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	1,526	0
Significant Unobservable Inputs (Level 3) [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	$ 0	$ 0

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair value transfer amount	$ 0	$ 0	$ 0

Fair Value Measurement - Sche_2

Fair Value Measurement - Schedule of Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value Inputs Asset Quantitative Information [Line Items]
Other real estate owned and repossessed assets	$ 6,877	$ 5,297
Impaired loans, Appraisal adjustments	0.00%	(4.80%)
Impaired loans, Liquidation expenses	0.00%	(7.60%)
Nonrecurring Fair Value Measurements [Member]
Fair Value Inputs Asset Quantitative Information [Line Items]
Impaired loans		$ 1,717
Other real estate owned and repossessed assets	$ 6,877	5,297
Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring Fair Value Measurements [Member]
Fair Value Inputs Asset Quantitative Information [Line Items]
Impaired loans	0	1,717
Other real estate owned and repossessed assets	$ 6,877	$ 5,297
Weighted Average [Member]
Fair Value Inputs Asset Quantitative Information [Line Items]
Impaired loans, Appraisal adjustments	0.00%	(4.80%)
Impaired loans, Liquidation expenses	0.00%	(7.60%)

Fair Value Measurement - Estima

Fair Value Measurement - Estimates Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial Assets
Cash and due from banks	$ 273,680	$ 117,572
Equity securities	12,784	13,457
Debt securities available-for-sale	2,008,232	1,261,865
Debt securities held-to-maturity	1,025,538	1,009,500
Net loans	7,677,521	6,296,157
Loans held for sale	55,913	20,320
Accrued interest receivable	39,465	29,728
Financial Liabilities
Deposits	8,941,758	7,043,588
Federal Home Loan Bank borrowings	1,131,253	948,203
Other borrowings	294,281	184,805
Subordinated debt and junior subordinated debt	189,745	164,327
Accrued interest payable	6,623	3,178
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial Assets
Cash and due from banks	273,680	117,572
Equity securities	12,784	11,391
Accrued interest receivable	39,465	29,728
Financial Liabilities
Deposits	7,428,158	5,766,531
Other borrowings	292,290	182,785
Accrued interest payable	6,623	3,178
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets
Debt securities available-for-sale	2,006,706	1,261,865
Debt securities held-to-maturity	1,013,788	1,023,191
Loans held for sale	55,913	20,320
Other assets - interest rate derivatives	6,451	7,351
Financial Liabilities
Deposits	1,532,063	1,287,005
Federal Home Loan Bank borrowings	1,123,441	944,706
Other borrowings	1,995	2,029
Subordinated debt and junior subordinated debt	179,497	146,484
Other liabilities - interest rate derivatives	6,527	7,345
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets
Debt securities available-for-sale	1,526
Debt securities held-to-maturity	573	593
Net loans	7,517,958	6,212,823
Carrying Amount [Member]
Financial Assets
Cash and due from banks	273,680	117,572
Equity securities	12,784	13,457
Debt securities available-for-sale	2,008,232	1,261,865
Debt securities held-to-maturity	1,025,538	1,009,500
Net loans	7,677,521	6,296,157
Loans held for sale	55,913	20,320
Other assets - interest rate derivatives	6,451	7,351
Accrued interest receivable	39,465	29,728
Financial Liabilities
Deposits	8,941,758	7,043,588
Federal Home Loan Bank borrowings	1,131,253	948,203
Other borrowings	294,281	184,805
Subordinated debt and junior subordinated debt	189,745	164,327
Other liabilities - interest rate derivatives	6,527	7,345
Accrued interest payable	6,623	3,178
Fair Value Estimate [Member]
Financial Assets
Cash and due from banks	273,680	117,572
Equity securities	12,784	13,457
Debt securities available-for-sale	2,008,232	1,261,865
Debt securities held-to-maturity	1,014,361	1,023,784
Net loans	7,517,958	6,212,823
Loans held for sale	55,913	20,320
Other assets - interest rate derivatives	6,451	7,351
Accrued interest receivable	39,465	29,728
Financial Liabilities
Deposits	8,960,221	7,053,536
Federal Home Loan Bank borrowings	1,123,441	944,706
Other borrowings	294,285	184,814
Subordinated debt and junior subordinated debt	179,497	146,484
Other liabilities - interest rate derivatives	6,527	7,345
Accrued interest payable	$ 6,623	3,178
Investments Measured at Net Asset Value [Member]
Financial Assets
Equity securities		$ 2,066

Revenue Recognition - Summary o

Revenue Recognition - Summary of Revenue Recognition (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule Of Revenue Recognition [Line Items]
Total net securities brokerage revenue	$ 1,836	$ 1,721	$ 5,315	$ 5,164
Allotment fees	311		311
Electronic banking fees	6,139	4,883	16,697	14,395
Mortgage banking income	1,521	1,103	4,297	3,511
Net gain or loss on sale of other real estate owned	150	(298)	641	9
Total Service Charges on Deposits [Member]
Schedule Of Revenue Recognition [Line Items]
Total trust fees/Total service charges on deposits	6,313		$ 16,282
Trust Account Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			Over time
Total trust fees/Total service charges on deposits	4,006		$ 11,856
WesMark Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			Over time
Total trust fees/Total service charges on deposits	2,259		$ 6,664
Total Trust Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Total trust fees/Total service charges on deposits	6,265	$ 5,358	$ 18,520	$ 17,073
Commercial Banking Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			Over time
Total trust fees/Total service charges on deposits	563		$ 1,406
Personal Service Charges [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			At a point in time & over time
Total trust fees/Total service charges on deposits	5,750		$ 14,876
Annuity Commissions [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			At a point in time
Total net securities brokerage revenue	1,326		$ 3,836
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	116		$ 304
Managed Money [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			Over time
Total net securities brokerage revenue	173		$ 477
Trail Commissions [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			Over time
Total net securities brokerage revenue	$ 221		$ 698
Allotment Fees [Member]
Schedule Of Revenue Recognition [Line Items]
Point of revenue recognition			At a point in time & over time
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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ 1,395,321	$ 1,341,408
Amounts reclassified from accumulated other comprehensive income	$ 537	$ 471	1,463	1,549
Total other comprehensive income			(27,315)	6,289
Ending Balance	1,927,269	1,394,558	1,927,269	1,394,558
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(18,626)	(17,758)
Acquired FFKT Medical benefit plan			4,235
Amounts reclassified from accumulated other comprehensive income	595	513	1,621	1,679
Total other comprehensive income			5,856	1,679
Ending Balance	(12,770)	(16,079)	(12,770)	(16,079)
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			(33,013)	4,740
Amounts reclassified from accumulated other comprehensive income	(9)		(9)	35
Total other comprehensive income			(33,022)	4,775
Adoption of Accounting Standard ASU 2016-01	(1,063)		(1,063)
Ending Balance	(47,335)	(5,115)	(47,335)	(5,115)
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	(49)	(42)	(149)	(165)
Total other comprehensive income			(149)	(165)
Ending Balance	232	357	232	357
Accumulated Other Comprehensive (Loss) Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(31,495)	(27,126)
Other comprehensive income before reclassifications			(33,013)	4,740
Acquired FFKT Medical benefit plan			4,235
Amounts reclassified from accumulated other comprehensive income			1,463	1,549
Total other comprehensive income			(27,315)	6,289
Adoption of Accounting Standard ASU 2016-01	(1,063)		(1,063)
Ending Balance	$ (59,873)	$ (20,837)	$ (59,873)	$ (20,837)

Comprehensive Income_(Loss) -_2

Comprehensive Income/(Loss) - Components of Accumulated Other Comprehensive Income (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains (Non-interest income)	$ (84)	$ (6)	$ (403)	$ (511)
Interest and dividends on securities (Interest and dividend income)	(20,290)	(14,573)	(55,918)	(43,299)
Employee benefits (Non-interest expense)	7,905	7,728	22,782	23,670
Provision for income taxes	6,516	10,527	20,855	30,801
Net effect on accumulated other comprehensive income for the period	537	471	1,463	1,549
Accumulated Unrealized Gains (Losses) on Debt Securities Available for Sale [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net effect on accumulated other comprehensive income for the period	(9)		(9)	35
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	(49)	(42)	(149)	(165)
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	595	513	1,621	1,679
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)	(11)		(11)	55
Provision for income taxes	2		2	(20)
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)	(64)	(66)	(195)	(256)
Provision for income taxes	15	24	46	91
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)	772	816	2,293	2,429
Provision for income taxes	$ (177)	$ (303)	$ (672)	$ (750)

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Allowance for credit losses associated with loan commitments	$ 684	$ 574	$ 647	$ 571
Liability associated with letters of credit	$ 200	$ 200

Commitments and Contingent Li_4

Commitments and Contingent Liabilities - Commitments to Extend Credit, Guarantees and Various Letters of Credit Outstanding (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Lines of credit	$ 1,855,388	$ 1,452,697
Loans approved but not closed	349,173	245,644
Overdraft limits	154,221	126,671
Letters of credit	41,515	31,951
Contingent obligations and other guarantees	$ 5,725	$ 6,700

Business Segments - Additional

Business Segments - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)Segment	Sep. 30, 2017USD ($)
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	$ 4,700	$ 3,900
Total non-fiduciary assets of the trust and investment services segment	$ 5.1	$ 1.7

Business Segments - Financial I

Business Segments - Financial Information by Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Interest income	$ 108,393	$ 85,489	$ 293,596	$ 247,573
Interest expense	18,460	11,235	48,127	30,461
Net interest income	89,933	74,254	245,469	217,112
Provision for credit losses	1,035	2,516	4,911	7,610
Net interest income after provision for credit losses	88,898	71,738	240,558	209,502
Non-interest income	26,224	20,899	73,715	65,906
Non-interest expense	76,120	55,754	194,234	166,023
Income before provision for income taxes	39,002	36,883	120,039	109,385
Provision for income taxes	6,516	10,527	20,855	30,801
Net income	32,486	26,356	99,184	78,584
Community Banking [Member]
Segment Reporting Information [Line Items]
Interest income	108,393	85,489	293,596	247,573
Interest expense	18,460	11,235	48,127	30,461
Net interest income	89,933	74,254	245,469	217,112
Provision for credit losses	1,035	2,516	4,911	7,610
Net interest income after provision for credit losses	88,898	71,738	240,558	209,502
Non-interest income	19,959	15,541	55,195	48,833
Non-interest expense	72,378	52,355	183,298	156,102
Income before provision for income taxes	36,479	34,924	112,455	102,233
Provision for income taxes	5,986	9,744	19,262	27,940
Net income	30,493	25,180	93,193	74,293
Trust and Investment Services [Member]
Segment Reporting Information [Line Items]
Non-interest income	6,265	5,358	18,520	17,073
Non-interest expense	3,742	3,399	10,936	9,921
Income before provision for income taxes	2,523	1,959	7,584	7,152
Provision for income taxes	530	783	1,593	2,861
Net income	$ 1,993	$ 1,176	$ 5,991	$ 4,291