F.N.B. (FNB) 10-K 28 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 31, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Trading Symbol	FNB
Entity Registrant Name	FNB CORP/PA/
Entity Central Index Key	37,808
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		323,523,445
Entity Public Float			$ 4,464,901,676

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks		$ 408,718	$ 303,526
Interest-bearing deposits with banks		70,725	67,881
Cash and Cash Equivalents		479,443	371,407
Securities available for sale		2,764,562	2,231,987
Securities held to maturity (fair value of $3,218,379 and $2,294,777)		3,242,268	2,337,342
Loans held for sale (includes $56,458 and $0 measured at fair value)	[1]	92,891	11,908
Loans and leases, net of unearned income of $50,680 and $52,723		20,998,766	14,896,943
Allowance for credit losses		(175,380)	(158,059)
Net Loans and Leases		20,823,386	14,738,884
Premises and equipment, net		336,540	243,956
Goodwill		2,249,188	1,032,129
Core deposit and other intangible assets, net		92,075	53,806
Bank owned life insurance		526,818	330,152
Other assets		810,464	493,246
Total Assets		31,417,635	21,844,817
Liabilities
Non-interest-bearing demand		5,720,030	4,205,337
Interest-bearing demand		9,571,038	6,931,381
Savings		2,488,178	2,352,434
Certificates and other time deposits		4,620,479	2,576,495
Total Deposits		22,399,725	16,065,647
Short-term borrowings		3,678,337	2,503,010
Long-term borrowings		668,173	539,494
Other liabilities		262,206	165,049
Total Liabilities		27,008,441	19,273,200
Stockholders’ Equity
Preferred stock - $0.01 par value; liquidation preference of $1,000 per share Authorized – 20,000,000 shares Issued – 110,877 shares		106,882	106,882
Common stock - $0.01 par value Authorized – 500,000,000 shares Issued – 325,095,055 and 212,378,494 shares		3,253	2,125
Additional paid-in capital		4,033,567	2,234,366
Retained earnings		367,658	304,397
Accumulated other comprehensive loss		(83,052)	(61,369)
Treasury stock – 1,629,915 and 1,318,947 shares at cost		(19,114)	(14,784)
Total Stockholders’ Equity		4,409,194	2,571,617
Total Liabilities and Stockholders’ Equity		$ 31,417,635	$ 21,844,817
[1]	Amount represents loans for which we have elected the fair value option. See Note 24.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Fair Value	$ 3,218,379	$ 2,294,777
Loans held for sale	56,458	0
Unearned income on loans	$ 50,680	$ 52,723
Preferred stock, par value (USD per Share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference per share (USD per Share)	$ 1,000	$ 1,000
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	110,877	110,877
Common stock, par value (USD per Share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	325,095,055	212,378,494
Treasury stock, shares (in shares)	1,629,915	1,318,947

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Income
Loans and leases, including fees	$ 861,867	$ 597,621	$ 482,086
Securities:
Taxable	97,728	71,853	58,148
Tax-exempt	19,741	9,011	6,405
Dividends	88	34	39
Other	902	444	117
Total Interest Income	980,326	678,963	546,795
Interest Expense
Deposits	71,582	41,239	31,207
Short-term borrowings	43,969	12,183	7,075
Long-term borrowings	18,341	14,029	10,291
Total Interest Expense	133,892	67,451	48,573
Net Interest Income	846,434	611,512	498,222
Provision for credit losses	61,073	55,752	40,441
Net Interest Income After Provision for Credit Losses	785,361	555,760	457,781
Non-Interest Income
Service charges	124,310	97,524	69,877
Trust services	23,121	21,173	20,934
Insurance commissions and fees	19,063	18,328	16,270
Securities commissions and fees	15,286	13,468	13,642
Capital markets income	16,603	15,471	10,246
Mortgage banking operations	19,977	12,106	8,619
Bank owned life insurance	11,693	10,249	8,135
Net securities gains	5,916	712	822
Other	16,480	12,730	13,865
Total Non-Interest Income	252,449	201,761	162,410
Non-Interest Expense
Salaries and employee benefits	326,893	239,798	202,068
Net occupancy	53,787	40,086	33,670
Equipment	49,361	38,046	31,869
Amortization of intangibles	17,517	11,210	8,305
Outside services	56,113	43,737	34,698
FDIC insurance	32,902	19,203	12,888
Supplies	8,326	10,834	8,064
Bank shares and franchise taxes	10,256	8,940	8,139
Telephone	10,218	7,159	6,234
Marketing	11,505	10,141	8,396
Other real estate owned	4,438	5,153	4,637
Merger-related	56,513	37,439	3,033
Other	43,712	39,387	28,548
Total Non-Interest Expense	681,541	511,133	390,549
Income Before Income Taxes	356,269	246,388	229,642
Income taxes	157,065	75,497	69,993
Net Income	199,204	170,891	159,649
Preferred stock dividends	8,041	8,041	8,041
Net Income Available to Common Stockholders	$ 191,163	$ 162,850	$ 151,608
Earnings per Common Share
Basic (in usd per share)	$ 0.63	$ 0.79	$ 0.87
Diluted (in usd per share)	0.63	0.78	0.86
Cash Dividends per Common Share (in usd per share)	$ 0.48	$ 0.48	$ 0.48

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 199,204	$ 170,891	$ 159,649
Securities available for sale:
Unrealized gains arising during the period, net of tax benefit of $3,224, $7,477 and $1,561	(5,744)	(13,886)	(2,899)
Reclassification adjustment for gains included in net income, net of tax expense of $230, $249 and $288	(411)	(463)	(534)
Derivative instruments:
Unrealized (losses) gains arising during the period, net of tax (benefit) expense of $(426), $2,739 and $1,887	(759)	5,086	3,504
Reclassification adjustment for gains included in net income, net of tax expense of $26, $685 and $1,035	(46)	(1,272)	(1,921)
Pension and postretirement benefit obligations:
Unrealized (losses) gains arising during the period, net of tax (benefit) expense of $(1), $161 and $(1,766)	(7)	299	(3,280)
Other comprehensive income (loss)	(6,967)	(10,236)	(5,130)
Comprehensive income	$ 192,237	$ 160,655	$ 154,519

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Unrealized gains arising during the period, net of tax benefit	$ 3,224	$ 7,477	$ 1,561
Reclassification adjustment for gains included in net income, net of tax expense	230	249	288
Unrealized (losses) gains arising during the period, net of tax (benefit) expense	(426)	2,739	1,887
Reclassification adjustment for gains included in net income, net of tax expense	26	685	1,035
Unrealized (losses) gains arising during the period, net of tax (benefit) expense	$ (1)	$ 161	$ (1,766)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Balance at beginning of period at Dec. 31, 2014	$ 2,021,456	$ 106,882	$ 1,754	$ 1,798,984	$ 176,120	$ (46,003)	$ (16,281)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	154,519				159,649	(5,130)
Dividends declared:
Preferred stock	(8,041)				(8,041)
Common stock: $0.48/share	(84,511)				(84,511)
Issuance of common stock	8,270		12	4,737			3,521
Restricted stock compensation	4,461			4,461
Tax benefit of stock-based compensation	28			28
Balance at end of period at Dec. 31, 2015	2,096,182	106,882	1,766	1,808,210	243,217	(51,133)	(12,760)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	160,655				170,891	(10,236)
Dividends declared:
Preferred stock	(8,041)				(8,041)
Common stock: $0.48/share	(101,670)				(101,670)
Issuance of common stock	11,406		19	13,411			(2,024)
Issuance of common stock – acquisitions	404,206		340	403,866
Restricted stock compensation	7,066			7,066
Tax benefit of stock-based compensation	1,813			1,813
Balance at end of period at Dec. 31, 2016	2,571,617	106,882	2,125	2,234,366	304,397	(61,369)	(14,784)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	192,237				199,204	(6,967)
Dividends declared:
Preferred stock	(8,041)				(8,041)
Common stock: $0.48/share	(142,618)				(142,618)
Issuance of common stock	2,980		12	7,298			(4,330)
Issuance of common stock – acquisitions	1,783,424		1,116	1,782,308
Assumption of warrant due to acquisition	1,394			1,394
Restricted stock compensation	8,201			8,201
Reclassification due to tax reform					14,716	(14,716)
Balance at end of period at Dec. 31, 2017	$ 4,409,194	$ 106,882	$ 3,253	$ 4,033,567	$ 367,658	$ (83,052)	$ (19,114)

Consolidated Statements of Sto8

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Common stock dividends per share (in usd per share)	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.48	$ 0.48	$ 0.48

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net income	$ 199,204	$ 170,891	$ 159,649
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	88,797	60,503	43,949
Provision for credit losses	61,073	55,752	40,441
Deferred tax expense	128,983	15,250	550
Net securities gains	(5,916)	(712)	(822)
Tax benefit of stock-based compensation	(822)	(1,813)	(28)
Loans originated for sale	(1,097,869)	(713,087)	(445,558)
Loans sold	1,046,762	716,705	455,623
Net gain on sale of loans	(17,223)	(10,746)	(8,666)
Net change in:
Interest receivable	(18,143)	(5,214)	(4,688)
Interest payable	1,978	(150)	760
Bank owned life insurance	(11,200)	(5,373)	(6,397)
Other, net	(96,718)	10,702	(11,333)
Net cash flows provided by operating activities	278,906	292,708	223,480
Investing Activities
Net change in loans and leases	(1,100,481)	(816,093)	(985,999)
Securities available for sale:
Purchases	(1,141,620)	(1,066,361)	(421,901)
Sales	786,762	615,199	33,499
Maturities	569,949	543,923	284,483
Securities held to maturity:
Purchases	(1,185,859)	(1,063,273)	(465,597)
Sales	57,050	0	0
Maturities	394,823	357,111	277,967
Purchase of bank owned life insurance	(50,124)	(16,587)	(72,688)
Withdrawal/surrender of bank owned life insurance	0	0	72,664
Increase in premises and equipment	(56,874)	(59,327)	(9,723)
Net cash received in business combinations	196,964	245,762	144,629
Net cash flows used in investing activities	(1,529,410)	(1,259,646)	(1,142,666)
Financing Activities
Demand (non-interest-bearing and interest-bearing) and savings accounts	405,777	933,793	1,259,765
Time deposits	757,021	(119,734)	(166,283)
Short-term borrowings	379,139	251,713	7,238
Proceeds from issuance of long-term borrowings	155,399	46,357	134,953
Repayment of long-term borrowings	(199,318)	(173,477)	(34,968)
Net proceeds from issuance of common stock	11,181	18,472	12,731
Tax benefit of stock-based compensation	0	1,813	28
Cash dividends paid:
Preferred stock	(8,041)	(8,041)	(8,041)
Common stock	(142,618)	(101,670)	(84,511)
Net cash flows provided by financing activities	1,358,540	849,226	1,120,912
Net Increase (Decrease) in Cash and Cash Equivalents	108,036	(117,712)	201,726
Cash and cash equivalents at beginning of year	371,407	489,119	287,393
Cash and Cash Equivalents at End of Year	$ 479,443	$ 371,407	$ 489,119

Nature of Operations

Nature of Operations	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	NATURE OF OPERATIONS F.N.B. Corporation (FNB), headquartered in Pittsburgh, Pennsylvania, is a diversified financial services company operating in eight states. We hold a significant retail deposit market share in metropolitan markets including: Pittsburgh, Pennsylvania; Baltimore, Maryland; Cleveland, Ohio; and Charlotte, Raleigh, Durham and the Piedmont Triad (Winston-Salem, Greensboro and High Point) in North Carolina. As of December 31, 2017 , we had 417 banking offices throughout Pennsylvania, Ohio, Maryland, West Virginia, North Carolina and South Carolina. We provide a full range of commercial banking, consumer banking, and wealth management solutions through our subsidiary network which is led by our largest affiliate, First National Bank of Pennsylvania (FNBPA). Commercial banking solutions include corporate banking, small business banking, investment real estate financing, business credit, capital markets and lease financing. Consumer banking provides a full line of consumer banking products and services including deposit products, mortgage lending, consumer lending and a complete suite of mobile and online banking services. Wealth management services include fiduciary and brokerage services, asset management, private banking and insurance. We also operate Regency Finance Company (Regency), which had 77 consumer finance offices in Pennsylvania, Ohio, Kentucky and Tennessee as of December 31, 2017 . The terms “FNB,” “the Corporation,” “we,” “us” and “our” throughout this Report mean F.N.B. Corporation and its subsidiaries, when appropriate.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation Our accompanying consolidated financial statements and these notes to the financial statements include subsidiaries in which we have a controlling financial interest. We own and operate FNBPA, First National Trust Company, First National Investment Services Company, LLC, F.N.B. Investment Advisors, Inc., First National Insurance Agency, LLC (FNIA), Regency, Bank Capital Services, LLC, and F.N.B. Capital Corporation, LLC, and include results for each of these entities in the accompanying consolidated financial statements. The accompanying consolidated financial statements include all adjustments that are necessary, in the opinion of management, to fairly reflect our financial position and results of operations in accordance with U.S. generally accepted accounting principles (GAAP). All significant intercompany balances and transactions have been eliminated. Certain prior period amounts have been reclassified to conform to the current period presentation. Such reclassifications had no impact on our net income and stockholders’ equity. Events occurring subsequent to the date of the December 31, 2017 balance sheet have been evaluated for potential recognition or disclosure in the consolidated financial statements through the date of the filing of the consolidated financial statements with the Securities and Exchange Commission (SEC). Use of Estimates Our accounting and reporting policies conform with GAAP. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could materially differ from those estimates. Material estimates that are particularly susceptible to significant changes include the allowance for credit losses, accounting for acquired loans, fair value of financial instruments, goodwill and other intangible assets, litigation and income taxes and deferred tax assets. Business Combinations Business combinations are accounted for by applying the acquisition method . Under the acquisition method, identifiable assets acquired and liabilities assumed, and any non-controlling interest in the acquiree at the acquisition date are measured at their fair values as of that date, and are recognized separately from goodwill. Results of operations of the acquired entities are included in the consolidated statements of income from the date of acquisition. Cash and Cash Equivalents Cash and cash equivalents include cash on hand, cash items in transit and amounts due from the Federal Reserve Bank (FRB) and other depository institutions (including interest-bearing deposits). Securities Investment securities, which consist of debt securities and certain equity securities, comprise a significant portion of our consolidated balance sheets. Such securities can be classified as trading, held to maturity or available for sale. As of December 31, 2017 and 2016 , we did not hold any trading securities. Securities held to maturity are comprised of debt securities, for which management has the positive intent and ability to hold until their maturity. Such securities are carried at cost, adjusted for related amortization of premiums and accretion of discounts through interest income from securities, and subject to evaluation for other-than-temporary impairment (OTTI). Securities that are not classified as trading or held to maturity are classified as available for sale. Our available for sale securities portfolio is comprised of debt securities and marketable equity securities. Such securities are carried at fair value with net unrealized gains and losses deemed to be temporary and OTTI attributable to non-credit factors reported separately as a component of other comprehensive income, net of tax. We evaluate our securities in a loss position for OTTI on a quarterly basis at the individual security level based on our intent to sell. If we intend to sell the debt security or it is more likely than not we will be required to sell the security before recovery of its amortized cost basis, OTTI must be recognized in earnings equal to the entire difference between the investments’ amortized cost basis and its fair value. If we do not intend to sell the debt security and it is not more likely than not that we will be required to sell the security before recovery of its amortized cost basis, OTTI must be separated into the amount representing credit loss and the amount related to all other market factors. The amount related to credit loss will be recognized in earnings. The amount related to other market factors will be recognized in other comprehensive income, net of applicable taxes. We perform our OTTI evaluation process in a consistent and systematic manner and include an evaluation of all available evidence. This process considers factors such as length of time and anticipated recovery period of the impairment, recent events specific to the issuer and recent experience regarding principal and interest payments. Securities Sold Under Agreements to Repurchase Securities sold under agreements to repurchase are accounted for as collateralized financing transactions and are recorded at the amounts at which the securities were sold plus accrued interest. Securities, generally U.S. government and federal agency securities, pledged as collateral under these financing arrangements cannot be sold or repledged by the secured party. The fair value of collateral either received from or provided to a third party is continually monitored and additional collateral is obtained or is requested to be returned to us as deemed appropriate. Derivative Instruments and Hedging Activities From time to time, we may enter into derivative transactions principally to protect against the risk of adverse price or interest rate movements on the value of certain assets and liabilities and on future cash flows. All derivative instruments are carried at fair value on the balance sheet as either an asset or liability. Accounting for the changes in fair value of a derivative is dependent upon whether or not it has been designated in a formal, qualifying hedging relationship. For derivatives in qualifying hedging relationships, we formally document all relationships between hedging instruments and hedged items, as well as our risk management objective and strategy for undertaking each hedge transaction. Changes in fair value of a derivative instrument that has been designated and qualifies as a cash flow hedge are recorded in accumulated other comprehensive income (AOCI), net of tax. Amounts are reclassified from AOCI to the consolidated statements of income in the period or periods in which the hedged transaction affects earnings. At the hedge’s inception and at least quarterly thereafter, a formal assessment is performed to determine whether changes in the fair values or cash flows of the derivative instruments have been highly effective in offsetting changes in fair values or cash flows of the hedged items and whether they are expected to be highly effective in the future. If it is determined a derivative instrument has not been or will not continue to be highly effective as a hedge, hedge accounting is discontinued. Derivative gains and losses under cash flow hedges not effective in hedging the change in fair value or expected cash flows of the hedged item are recognized immediately in the consolidated statements of income. In addition, we enter into interest rate swap agreements to meet the financing, interest rate and equity risk management needs of qualifying commercial loan customers. These agreements provide the customer the ability to convert from variable to fixed interest rates. We then enter into positions with a derivative counterparty in order to offset our exposure on the fixed components of the customer agreements. The credit risk associated with derivatives executed with customers is essentially the same as that involved in extending loans and is subject to normal credit policies and monitoring. We seek to minimize counterparty credit risk by entering into transactions with only high-quality institutions. These arrangements meet the definition of derivatives, but are not designated as qualifying hedging relationships. The interest rate swap agreement with the loan customer and with the counterparty are reported at fair value in other assets and other liabilities on the consolidated balance sheets with any resulting gain or loss recorded in current period earnings as other income. Loans Held for Sale and Loan Commitments Certain of our residential mortgage loans are originated or purchased for sale in the secondary mortgage loan market. Effective January 1, 2017, we made an automatic election to account for all future originated or purchased residential mortgage loans held for sale under the fair value option (FVO). The FVO election is intended to better reflect the underlying economics and better facilitate the economic hedging of the loans. The FVO is applied on an instrument by instrument basis and is an irrevocable election. Additionally, with the election of the FVO, fees and costs associated with the origination and acquisition of residential mortgage loans held for sale are expensed as incurred, rather than deferred. Changes in fair value under the FVO are recorded in mortgage banking operations non-interest income on the consolidated statements of income. Fair value is determined on the basis of rates obtained in the respective secondary market for the type of loan held for sale. Prior to the FVO election, loans were generally sold at a premium or discount from the carrying amount of the loan which represented the lower of cost or fair value. Gain or loss on the sale of loans is recorded in mortgage banking operations non-interest income. Interest income on loans held for sale is recorded in interest income. We routinely issue interest rate lock commitments for residential mortgage loans that we intend to sell. These interest rate lock commitments are considered derivatives. We also enter into loan sale commitments to sell these loans when funded to mitigate the risk that the market value of residential mortgage loans may decline between the time the rate commitment is issued to the customer and the time we sell the loan. These loan sale commitments are also derivatives. Both types of derivatives are recorded at fair value on the consolidated balance sheets with changes in fair value recorded in mortgage banking operations non-interest income. We also originate loans guaranteed by the Small Business Administration (SBA) for the purchase of businesses, business startups, business expansion, equipment, and working capital. All SBA loans are underwritten and documented as prescribed by the SBA. Starting in the first quarter of 2017, the guaranteed portion of SBA loans originated with the intention to sell on the secondary market are classified as held for sale and are carried at the lower of cost or fair value. At the time of the sale, we allocate the carrying value of the entire loan between the guaranteed portion sold and the unguaranteed portion retained based on their relative fair value which results in a discount recorded on the retained portion of the loan. The guaranteed portion is typically sold at a premium and the gain is recognized in other income for any net premium received in excess of the relative fair value of the portion of the loan transferred. The net carrying value of the retained portion of the loans is included in the appropriate loan classification for disclosure purposes, primarily commercial real estate or commercial and industrial. Loans (Excluding Acquired Loans) Loans we intend to hold for the foreseeable future or until maturity or payoff are reported at their outstanding principal balances, net of any deferred origination fees or costs. Interest income on loans is computed over the term of the loans using the effective interest method. Loan origination fees and certain direct costs incurred to extend credit are deferred and amortized over the term of the loan or loan commitment period as an adjustment to the related loan yield. Non-performing Loans Interest is not accrued on loans where collectability is uncertain. We discontinue interest accruals on loans generally when principal or interest is due and has remained unpaid for a certain number of days unless the loan is both well secured and in the process of collection. Commercial loans are placed on non-accrual at 90 days, installment loans are placed on non-accrual at 120 days and residential mortgages and consumer lines of credit are generally placed on non-accrual at 180 days. Past due status is based on the contractual terms of the loan. When a loan is placed on non-accrual status, all unpaid interest is reversed against interest income and the amortization of deferred fees and costs is suspended. Payments subsequently received are generally applied to either principal or interest or both, depending on management’s evaluation of collectability. A loan is returned to accrual status when principal and interest are no longer past due and collectability is probable. This generally requires a sustained period of timely principal and interest payments. Loans are generally written off when deemed uncollectible or when they reach a predetermined number of days past due depending upon loan product, terms, and other factors. Recoveries of amounts previously charged off are credited to the allowance for credit losses. We consider a loan impaired when, based on current information and events, it is probable that we will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered in determining impairment include payment status, collateral value and the probability of collecting scheduled principal and interest payments when due. The impairment loss is measured by either the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s obtainable market price, or the fair value of the collateral, less estimated selling costs, if the loan is collateral dependent. Acquired impaired loans are not classified as non-performing assets as the loans are considered to be performing. Restructured loans are those in which concessions of terms have been made as a result of deterioration in a borrower’s financial condition. In general, the modification or restructuring of a debt constitutes a troubled debt restructuring (TDR) if we for economic or legal reasons related to the borrower’s financial difficulties grant a concession to the borrower that we would not otherwise consider under current market conditions. Debt restructurings or loan modifications for a borrower occur in the normal course of business and do not necessarily constitute TDRs. To designate a loan as a TDR, the presence of both borrower financial distress and a concession of terms must exist. Additionally, a loan designated as a TDR does not necessarily result in the automatic placement of the loan on non-accrual status. When the full collection of principal and interest is reasonably assured on a loan designated as a TDR and the borrower does not otherwise meet the criteria for non-accrual status, we will continue to accrue interest on the loan. A restructured acquired loan that is accounted for as a component of a pool in accordance is not considered a TDR. Allowance for Credit Losses The allowance for credit losses is established as losses are estimated to have occurred through a provision charged to earnings. Loan losses are charged against the allowance for credit losses when management believes the uncollectability of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance for credit losses. Allowances for impaired commercial loans over $500,000 are generally determined based on collateral values or the present value of estimated cash flows. All other impaired loans are evaluated in the aggregate based on loan segment loss given default. Changes in the allowance for credit losses related to impaired loans are charged or credited to the provision for credit losses. The allowance for credit losses is maintained at a level that, in management’s judgment, is believed appropriate to absorb probable losses associated with specifically identified loans, as well as estimated probable credit losses inherent in the remainder of the loan portfolio. The appropriateness of the allowance for credit losses is based on management’s evaluation of potential loan losses in the loan portfolio, which includes an assessment of past experience, current economic conditions in specific industries and geographic areas, general economic conditions, known and inherent risks in the loan portfolio, the estimated value of underlying collateral and residuals and changes in the composition of the loan portfolio. Determination of the allowance for credit losses is inherently subjective as it requires significant estimates, including the amounts and timing of expected future cash flows on impaired loans, estimated losses on pools of homogeneous loans based on transition matrices with predefined loss emergence periods and consideration of qualitative factors, all of which are susceptible to significant change. Acquired Loans Acquired loans (impaired and non-impaired) are initially recorded at their acquisition-date fair values. Fair values are based on a discounted cash flow methodology that involves assumptions and judgments as to credit risk, default rates, loss severity, collateral values, discount rates, payment speeds, prepayment risk, and liquidity risk. The carryover of allowance for credit losses related to acquired loans is prohibited as any credit losses in the loans are included in the determination of the fair value of the loans at the acquisition date. The allowance for credit losses on acquired loans reflects only those losses incurred after acquisition and represents the present value of cash flows expected at acquisition that is no longer expected to be collected. At acquisition, we consider the following factors as indicators that an acquired loan has evidence of deterioration in credit quality and is therefore impaired and in the scope of ASC 310-30: • loans that were 90 days or more past due; • loans that had an internal risk rating of substandard or worse. Substandard is consistent with regulatory definitions and is defined as having a well-defined weakness that jeopardizes liquidation of the loan; • loans that were classified as non-accrual by the acquired bank at the time of acquisition; or • loans that had been previously modified in a TDR. Any acquired loans that were not individually in the scope of ASC 310-30 because they didn’t meet the criteria above were pooled into groups of similar loans based on various factors including borrower type, loan purpose, and collateral type. For these pools, we used certain loan information, including outstanding principal balance, estimated expected losses, weighted average maturity, weighted average margin, and weighted average interest rate along with estimated prepayment rates, probability of default and loss given default to estimate the expected cash flow for each loan pool. We believe analogizing to ASC 310-30 is the more appropriate option to follow in accounting for discount accretion on non-impaired acquired loans other than revolving loans and therefore account for such loans in accordance with ASC 310-30. ASC 310-30 guidance does not apply to revolving loans. Consequently, discount accretion on revolving loans acquired is accounted for using the ASC 310-20 approach. The excess of cash flows expected to be collected at acquisition over recorded fair value is referred to as the accretable yield. The accretable yield is recognized into income over the remaining life of the loan, or pool of loans, using an effective yield method, if the timing and/or amount of cash flows expected to be collected can be reasonably estimated (the accretion model). If the timing and/or amount of cash flows expected to be collected cannot be reasonably estimated, the cost recovery method of income recognition must be used. The difference between the loan’s total scheduled principal and interest payments over all cash flows expected at acquisition is referred to as the non-accretable difference. The non-accretable difference represents contractually required principal and interest payments which we do not expect to collect. Over the life of the acquired loan, we continue to estimate cash flows expected to be collected. Decreases in expected cash flows, other than from prepayments or rate adjustments, are recognized as impairments through a charge to the provision for credit losses resulting in an increase in the allowance for credit losses. Subsequent improvements in cash flows result in first, reversal of existing valuation allowances recognized subsequent to acquisition, if any, and next, an increase in the amount of accretable yield to be subsequently recognized on a prospective basis over the loan’s remaining life. Acquired loans that met the criteria for non-accrual of interest prior to acquisition are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of expected cash flows on such loans. Accordingly, we do not consider acquired contractually delinquent loans to be non-accrual or non-performing and continue to recognize interest income on these loans using the accretion model. Premises and Equipment Premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the asset’s estimated useful life. Leasehold improvements are expensed over the lesser of the asset’s estimated useful life or the term of the lease including renewal periods when reasonably assured. Useful lives are dependent upon the nature and condition of the asset and range from 3 to 40 years. Maintenance and repairs are charged to expense as incurred, while major improvements are capitalized and amortized to expense over the identified useful life. Premises and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value may not be recoverable. Cloud Computing Arrangements Beginning in 2016, for new or materially modified contracts, we prospectively adopted new accounting principles to evaluate fees paid for cloud computing arrangements to determine if those arrangements include the purchase of or license to use software that should be accounted for separately as internal-use software. If a contract includes the purchase or license to use software that should be accounted for separately as internal-use software, the contract is amortized over the software’s identified useful life in amortization of intangibles. For contracts that do not include a software license, the contract is accounted for as a service contract with fees paid recorded in other non-interest expense. Other Real Estate Owned Other real estate owned (OREO) is comprised principally of commercial and residential real estate properties obtained in partial or total satisfaction of loan obligations. OREO acquired in settlement of indebtedness is included in other assets initially at the lower of estimated fair value of the asset less estimated selling costs or the carrying amount of the loan. Changes to the value subsequent to transfer are recorded in non-interest expense along with direct operating expenses. Gains or losses not previously recognized resulting from sales of OREO are recognized in non-interest expense on the date of sale. Goodwill and Other Intangible Assets Goodwill represents the excess of the cost of an acquisition over the fair value of the net assets acquired. Other intangible assets represent purchased assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights. Intangible assets that have finite lives, such as core deposit intangibles, customer relationship intangibles and renewal lists, are amortized over their estimated useful lives and subject to periodic impairment testing. Core deposit intangibles are primarily amortized over ten years using accelerated methods. Customer renewal lists are amortized over their estimated useful lives which range from eight to thirteen years . Goodwill and other intangibles are subject to impairment testing at the reporting unit level, which must be conducted at least annually. We perform impairment testing during the fourth quarter of each year, or more frequently if impairment indicators exist. We also continue to monitor other intangibles for impairment and to evaluate carrying amounts, as necessary. Determining the fair value of a reporting unit under the goodwill impairment test is judgmental and often involves the use of significant estimates and assumptions. Similarly, estimates and assumptions are used in determining the fair value of other intangible assets. Estimates of fair value are primarily determined using discounted cash flows, market comparisons and recent transactions. These approaches use significant estimates and assumptions including projected future cash flows, discount rates reflecting the market rate of return, projected growth rates and determination and evaluation of appropriate market comparables. However, future events could cause us to conclude that goodwill or other intangibles have become impaired, which would result in recording an impairment loss. Any resulting impairment loss could have a material adverse impact on our financial condition and results of operations. Loan Servicing Rights We have two primary classes of servicing rights, residential mortgage loan servicing and SBA-guaranteed loan servicing. We recognize the right to service residential mortgage loans and SBA-guaranteed loans for others as an asset whether we purchase the servicing rights or as a result from a sale of loans that we originate when the servicing is contractually separated from the underlying loan and retained by us. We initially record servicing rights at fair value in other assets, net on the consolidated balance sheet. Subsequently, servicing rights are measured at the lower of cost or fair value. Servicing rights are amortized in proportion to, and over the period of, estimated net servicing income in mortgage banking operations income for residential mortgage loans and non-interest income for SBA-guaranteed loans. The amount and timing of estimated future net cash flows are updated based on actual results and updated projections. Mortgage servicing rights (MSRs) are separated into pools based on common risk characteristics of the underlying loans and evaluated for impairment at least quarterly. SBA-guaranteed servicing rights are evaluated for impairment at least quarterly on an aggregate basis. Impairment, if any, is recognized when carrying value exceeds the fair value as determined by calculating the present value of expected net future cash flows. If impairment exists at the pool level for residential mortgage loans or on an aggregate basis for SBA-guaranteed loans, the servicing right is written down through a valuation allowance and is charged against mortgage banking operations income or non-interest income, respectively. Bank-Owned Life Insurance (BOLI) We have purchased life insurance policies on certain current and former directors, officers and employees for which the Corporation is the owner and beneficiary. These policies are recorded in the consolidated balance sheet at their cash surrender value, or the amount that could be realized by surrendering the policies. Tax-exempt income from death benefits and changes in the net cash surrender value are recorded in bank owned life insurance income. Low Income Housing Tax Credit Partnerships We invest in various affordable housing projects that qualify for low income housing tax credits (LIHTCs). The net investments are recorded in other assets on the consolidated balance sheets. These investments generate a return through the realization of federal tax credits. We use the proportional amortization method to account for a majority of our investments in these entities. LIHTCs that do not meet the requirements of the proportional amortization method are recognized using the equity method. Our net investment in LIHTCs was $20.9 million and $14.0 million at December 31, 2017 and 2016 , respectively. Our unfunded commitments in LIHTCs were $67.2 million and $9.8 million at December 31, 2017 and 2016 , respectively. Income Taxes We file a consolidated federal income tax return. The provision for federal and state income taxes is based on income reported on the consolidated financial statements, rather than the amounts reported on the respective income tax returns. Deferred tax assets and liabilities are computed using tax rates expected to apply to taxable income in the years in which those assets and liabilities are expected to be realized. The effect on deferred tax assets and liabilities resulting from a change in tax rates is recognized as income or expense in the period that the change in tax rates is enacted. Beginning in the fourth quarter of 2017, we made an accounting policy election to reclassify the stranded tax effects that relate to a change in the federal tax rate from AOCI to retained earnings in accordance with newly adopted accounting guidance. We believe this change in accounting policy reduces the cost and complexity of accounting for stranded tax effects due to a change in federal tax rates. We make certain estimates and judgments in determining income tax expense for financial statement purposes. These estimates and judgments are applied in the calculation of certain tax credits and in the calculation of the deferred income tax expense or benefit associated with certain deferred tax assets and liabilities. Significant changes to these estimates may result in an increase or decrease to our tax provision in a subsequent period. We recognize interest and/or penalties related to income tax matters in income tax expense. We assess the likelihood that we will be able to recover our deferred tax assets. If recovery is not likely, we will increase our provision for income taxes by recording a valuation allowance against the deferred tax assets that are unlikely to be recovered. We believe that we will ultimately recover the deferred tax assets recorded on our balance sheet. However, should there be a change in our ability to recover our deferred tax assets, the effect of this change would be recorded through the provision for income taxes in the period during which such change occurs. We periodically review the tax positions we take on our tax return and apply a more likely than not recognition threshold for all tax positions that are uncertain. The amount recognized in the financial statements is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the more likely than not test, no tax benefit is recorded. Marketing Costs Marketing costs are generally expensed as incurred. Per Share Amounts Earnings per common share is computed using net income available to common stockholders, which is net income adjusted for preferred stock dividends. Basic earnings per common share is calculated by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding, net of unvested shares of restricted stock. Diluted earnings per common share is calculated by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding, adjusted for the dilutive effect of potential common shares issuable for stock options, warrants and restricted shares, as calculated using the treasury stock method. Adjustments to net income available to common stockholders and the weighted average number of shares of common stock outstanding are made only when such adjustments dilute earnings per common share. Beginning in 2017, the assumed proceeds from applying the treasury stock method when computing diluted earnings per share excludes the amount of excess tax benefits that would have been recognized in accumulated paid-in capital in accordance with newly adopted accounting guidance. Retirement Plans FNB sponsors retirement plans f

New Accounting Standards

New Accounting Standards	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
New Accounting Standards	NEW ACCOUNTING STANDARDS The following paragraphs summarize accounting pronouncements issued by the Financial Accounting Standards Board (FASB) that we recently adopted or will be adopting in the future. Reporting Comprehensive Income Accounting Standards Update (ASU or Update) 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , allows for the reclassification from other comprehensive income to retained earnings for stranded tax effects resulting from the enacted tax bill H.R.1, commonly referred to as the Tax Cuts and Jobs Act (the TCJA). The Update also allows an accounting policy election to reclassify other stranded tax effects that relate to the TCJA but not directly related to the change in federal tax rate. This Update is effective in the first quarter of 2019. Early adoption is permitted for reporting periods for which financial statements have not yet been issued. We adopted this Update in the fourth quarter of 2017 by retrospective application. Upon adoption, the Corporation made a policy election to reclassify stranded tax effects of approximately $14.7 million from AOCI to retained earnings using the specific identification method. Stock-Based Compensation ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting , provides guidance about which changes to the terms and conditions of a share-based payment award requires the application of modification accounting. The Update is effective in the first quarter of 2018. Early adoption is permitted. This Update was adopted in the third quarter of 2017 by prospective application to awards modified on or after the adoption date. This Update did not have a material effect on our consolidated financial statements. ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The Update was adopted in the first quarter of 2017 by an application method determined by the type of transaction impacted by the adoption. This Update did not have a material effect on our consolidated financial statements. Securities ASU 2017-08, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities which shortens the amortization period for the premium on certain purchased callable securities to the earliest call date. The accounting for purchased callable debt securities held at a discount does not change. The Update is effective in the first quarter of 2019. Early adoption is permitted. The Update is to be applied using a modified retrospective transition method and is not expected to have a material effect on our consolidated financial statements. Retirement Benefits ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, requires that an employer disaggregate the service cost component from the other components of net benefit cost. The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allows only the service cost component of net benefit cost to be eligible for capitalization. The Update is effective the first quarter of 2018. Early adoption is permitted. The Update is to be applied using a retrospective transition method to adopt the requirement for separate presentation in the income statement of service costs and other components and a prospective transition method to adopt the requirement to limit the capitalization of benefit costs to the service cost component. This Update is not expected to have a material effect on our consolidated financial statements. Goodwill ASU 2017-04, Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment , eliminates the requirement of Step 2 in the current guidance to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value in Step 1 of the current guidance. The Update is effective the first quarter of 2020. Early adoption is permitted for annual or interim goodwill impairment tests with a measurement date after January 1, 2017. We adopted this Update in the first quarter of 2017 and it did not have a material effect on our consolidated financial statements. Business Combinations ASU 2017-01, Business Combinations (Topic 850): Clarifying the Definition of a Business , clarifies the definition of a business with the objective of providing guidance to assist in the evaluation of whether transactions should be accounted for as acquisitions (disposals) of assets or businesses. The Update is effective for the first quarter of 2018. Early adoption is permitted for transactions that occurred before the issuance date or effective date of the Update if the transactions were not reported in financial statements that have been issued or made available for issuance. We adopted this Update in the first quarter of 2017. This Update is applied prospectively and did not have a material effect on our consolidated financial statements. Statement of Cash Flows ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force), adds or clarifies guidance on eight cash flow issues. The Update is effective the first quarter of 2018. This Update will be applied retrospectively to all periods presented. Early adoption is permitted. This Update is not expected to have a material effect on our consolidated financial statements. Credit Losses ASU 2016-13 , Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , replaces the current incurred loss impairment methodology with a methodology that reflects current expected credit losses (commonly referred to as “CECL”) for most financial assets measured at amortized cost and certain other instruments, including loans, held-to-maturity debt securities, net investments in leases and off-balance sheet credit exposures. CECL requires loss estimates for the remaining life of the financial asset at the time the asset is originated or acquired, considering historical experience, current conditions and reasonable and supportable forecasts. In addition, the Update will require the use of a modified available-for-sale debt security impairment model and eliminate the current accounting for purchased credit impaired loans and debt securities. The Update is effective the first quarter of 2020 under a cumulative-effect adjustment to retained earnings. Early adoption is permitted for fiscal years beginning after December 15, 2018. The CECL model is a significant change from existing GAAP and may result in a material change to the Corporation’s accounting for financial instruments. We are reviewing our business processes, information systems and controls to support recognition and disclosures under this Update. This review includes an assessment of our existing credit models and the financial statement disclosure requirements. The impact of this Update will be dependent on the portfolio composition, credit quality and economic conditions at the time of adoption. Revenue Recognition ASU 2014-09, Revenue from Contracts with Customers (Topic 606), modifies the guidance used to recognize revenue from contracts with customers for transfers of goods and services and transfers of nonfinancial assets, unless those contracts are within the scope of other guidance. The guidance also requires new qualitative and quantitative disclosures about contract balances and performance obligations. We will adopt ASU 2014-09 in the first quarter of 2018 under the modified retrospective method where the cumulative effect is recognized at the date of initial application. Based on our evaluation under the current guidance, we estimate that substantially all of our interest income and non-interest income will not be impacted by the adoption of this ASU because either the revenue from those contracts with customers is covered by other guidance in U.S. GAAP or the revenue recognition outcomes anticipated with the adoption of this ASU will likely be similar to our current revenue recognition practices. In addition, we reviewed, and where necessary, enhanced our business processes, systems and controls to support recognition and disclosures under the new standard. The adoption of this Update is not expected to have a material effect on our consolidated financial statements. Investments ASU 2016-07, Investments—Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting, eliminates the requirement for an investor to retrospectively apply the equity method when an investment that it had accounted for by another method qualifies for use of the equity method. The Update was adopted in the first quarter of 2017 by prospective application. This Update did not have a material effect on our consolidated financial statements. Derivative and Hedging Activities ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities , improves the financial reporting of hedging to better align with the entity’s risk management activities. In addition, this Update makes certain targeted improvements to simplify the application of the current hedge accounting guidance. The Update is effective in the first quarter of 2019 by modified retrospective method. The presentation and disclosure guidance are applied prospectively. Early adoption is permitted. We are currently assessing the potential impact to our consolidated financial statements. ASU 2016-06, Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments (a consensus of the Emerging Issues Task Force), provides clarification that determination of whether an embedded contingent put or call option in a financial instrument is clearly and closely related to the debt host requires only an analysis of the four-step decision sequence described in ASC 815-15-25-42. The Update was adopted in the first quarter of 2017 by modified retrospective application. This Update did not have a material effect on our consolidated financial statements. ASU 2016-05, Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships (a consensus of the Emerging Issues Task Force), clarifies that a change in counterparty to a derivative instrument that has been designated as a hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided all other hedge accounting criteria continue to be met. The Update was adopted in the first quarter of 2017 by prospective application. This Update did not have a material effect on our consolidated financial statements. Extinguishments of Liabilities ASU 2016-04, Liabilities—Extinguishments of Liabilities (Subtopic 405-20): Recognition of Breakage for Certain Prepaid Stored-Value Products (a consensus of the Emerging Issues Task Force), requires entities that sell prepaid stored-value products redeemable for goods, services or cash at third-party merchants to recognize breakage. The Update is effective in the first quarter of 2018 with either the modified retrospective method by means of a cumulative-effect adjustment to retained earnings or retrospective application. Early adoption is permitted. This Update is not expected to have a material effect on our consolidated financial statements. Leases ASU 2016-02, Leases (Topic 842), requires lessees to put most leases on their balance sheets but recognize expenses in the income statement similar to current accounting. In addition, the Update changes the guidance for sale-leaseback transactions, initial direct costs and lease executory costs for most entities. All entities will classify leases to determine how to recognize lease related revenue and expense. The Update is effective in the first quarter of 2019 with modified retrospective application including a number of optional practical expedients. Early adoption is permitted. We are currently assessing the potential impact to our consolidated financial statements. Financial Instruments – Recognition and Measurement ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, amends the presentation and accounting for certain financial instruments, including liabilities measured at fair value under the fair value option, and equity investments. The guidance also updates fair value presentation and disclosure requirements for financial instruments measured at amortized cost. The Update is effective in the first quarter of 2018 with a cumulative-effect adjustment as of the beginning of the fiscal year of adoption. Early adoption is prohibited except for the provision requiring the recognition of changes in fair value related to changes in an entity’s own credit risk in other comprehensive income for financial liabilities measured using the fair value option. This Update is not expected to have a material effect on our consolidated financial statements.

Mergers and Acquisitions

Mergers and Acquisitions	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Mergers and Acquisitions	MERGERS AND ACQUISITIONS Yadkin Financial Corporation On March 11, 2017, we completed our acquisition of Yadkin Financial Corporation (YDKN), a bank holding company based in Raleigh, North Carolina. YDKN’s banking affiliate, Yadkin Bank, was also merged into FNBPA on March 11, 2017. YDKN’s results of operations have been included in our consolidated statements of income since that date. The acquisition enabled us to enter several North Carolina markets, including Raleigh, Charlotte and the Piedmont Triad, which is comprised of Winston-Salem, Greensboro and High Point. We also completed the core systems conversion activities during the first quarter. On the acquisition date, the fair values of YDKN included $6.8 billion in assets, of which there was $5.1 billion in loans and $5.2 billion in deposits. The acquisition was valued at $1.8 billion based on the acquisition-date FNB common stock closing price of $15.97 and resulted in FNB issuing 111,619,622 shares of common stock in exchange for 51,677,565 shares of YDKN common stock. Under the terms of the merger agreement, shareholders of YDKN received 2.16 shares of FNB common stock for each share of YDKN common stock and cash in lieu of fractional shares. YDKN’s fully vested and outstanding stock options were converted into options to purchase and receive FNB common stock. In conjunction with the acquisition, we assumed a warrant that was issued by YDKN to the U.S. Department of the Treasury (UST) under the Capital Purchase Program (CPP). Based on the exchange ratio, this warrant, which expires in 2019, was converted into a warrant to purchase up to 207,320 shares of FNB common stock with an exercise price of $9.63 . The acquisition of YDKN constituted a business combination and has been accounted for using the acquisition method of accounting, and accordingly, assets acquired, liabilities assumed and consideration exchanged were recorded at fair value on the acquisition date. The determination of fair values required management to make certain estimates about discount rates, future expected cash flows, market conditions, and other future events that are highly subjective in nature and may require adjustments, which can be updated for up to a year following the acquisition. As of December 31, 2017 , we believe that all fair values and related adjustments to goodwill have been recorded with the exception of acquired premises and equipment which were recorded at provisional amounts. The following table presents the provisional estimate and fair value amounts recorded for certain acquired items: (in thousands) Acquired Asset or Liability Balance Sheet Line Item Provisional Estimate Fair Value Increase (Decrease) Loans and leases Loans and leases, net $ 5,116,497 $ 5,114,355 $ (2,142 ) Premises and equipment Premises and equipment, net 95,208 70,031 (25,177 ) Deferred taxes Other assets 94,307 125,100 30,793 Other liabilities Other liabilities 70,761 68,264 (2,497 ) These adjustments to fair value did not result in any significant impact on the consolidated income statement for 2017. Based on the purchase price allocation, we recorded $1.2 billion in goodwill and $55.7 million in core deposit intangibles as a result of the acquisition. The core deposit intangible asset is being amortized over the estimated useful life of approximately ten years utilizing an accelerated method. Goodwill is not amortized, but is periodically evaluated for impairment. None of the goodwill is deductible for income tax purposes. The following pro forma financial information for the periods presented reflects our estimated consolidated pro forma results of operations as if the YDKN acquisition occurred on January 1, 2016, unadjusted for potential cost savings and other business synergies we expect to receive as a result of the acquisition: (dollars in thousands, except per share data) FNB YDKN Pro Forma Adjustments Pro Forma Combined Twelve Months Ended December 31, 2017 Revenue (net interest income and non-interest income) $ 1,077,984 $ 74,574 $ 3,419 $ 1,155,977 Net income 227,478 22,435 (1,165 ) 248,748 Net income available to common stockholders 219,437 22,435 (1,165 ) 240,707 Earnings per common share – basic 0.92 0.78 — 0.80 Earnings per common share – diluted 0.91 0.77 — 0.79 Twelve Months Ended December 31, 2016 Revenue $ 813,273 $ 293,655 $ (5,290 ) $ 1,101,638 Net income 170,891 55,168 (7,862 ) 218,197 Net income available to common stockholders 162,850 55,168 (7,862 ) 210,156 Earnings per common share – basic 0.79 1.15 — 0.67 Earnings per common share – diluted 0.78 1.14 — 0.67 The pro forma adjustments reflect amortization and associated taxes related to the preliminary purchase accounting adjustments made to record various acquired items at fair value. In connection with the YDKN acquisition, we incurred expenses related to systems conversions and other costs of integrating and conforming acquired operations with and into FNB. These merger-related expenses, that were expensed as incurred, amounted to $56.2 million for the year ended December 31, 2017 . Contract terminations and severance costs comprised 30.9% and 24.3% , respectively, of the merger-related expenses, with the remainder consisting of other non-interest expenses, including professional services, marketing and advertising, technology and communications, occupancy and equipment, and charitable contributions. We also incurred issuance costs of $0.6 million which were charged to additional paid-in capital. Branch Purchase – Fifth Third Bank On April 22, 2016, we completed our purchase of 17 branch-banking locations and certain consumer loans in the Pittsburgh, Pennsylvania metropolitan area from Fifth Third Bank (Fifth Third). The fair value of the acquired assets totaled $312.4 million , including $198.9 million in cash, $95.4 million in loans and $14.1 million in fixed and other assets. We also assumed $302.5 million in deposits, for which we paid a deposit premium of 1.97% , as part of the transaction. The assets and liabilities relating to these purchased branches were recorded on our balance sheet at their fair values as of April 22, 2016, and the related results of operations for these branches have been included in our consolidated income statement since that date. We recorded $14.1 million in goodwill and $4.1 million in core deposit intangibles as a result of the purchase transaction. The goodwill for this transaction is deductible for income tax purposes. Metro Bancorp, Inc. On February 13, 2016, we completed our acquisition of Metro Bancorp, Inc. (METR), a bank holding company based in Harrisburg, Pennsylvania. The acquisition enhanced our distribution and scale across Central Pennsylvania, strengthened our position as the largest Pennsylvania-based regional bank and allowed us to leverage the significant infrastructure investments made in connection with the expansion of our product offerings and risk management systems. On the acquisition date, the fair values of METR included $2.8 billion in assets, of which there was $1.9 billion in loans and $2.3 billion in deposits. The acquisition was valued at $404.2 million and resulted in FNB issuing 34,041,181 shares of common stock in exchange for 14,345,319 shares of METR common stock. We also acquired the fully vested outstanding stock options of METR. The assets and liabilities of METR were recorded on our consolidated balance sheet at their fair values as of the acquisition date, and METR’s results of operations have been included in our consolidated income statement since that date. METR’s banking affiliate, Metro Bank, was merged into FNBPA on February 13, 2016. Based on the purchase price allocation, we recorded $185.1 million in goodwill and $24.2 million in core deposit intangibles as a result of the acquisition. None of the goodwill is deductible for income tax purposes as the acquisition is accounted for as a tax-free exchange for tax purposes. In connection with the METR acquisition, we incurred expenses related to systems conversions and other costs of integrating and conforming acquired operations with and into FNB. These merger-related charges, that were expensed as incurred, amounted to $0.4 million and $31.0 million for the years ended December 31, 2017 and 2016 . Severance costs comprised 39.9% of the merger-related expenses, with the remainder consisting of other non-interest expenses, including professional services, marketing and advertising, technology and communications, occupancy and equipment, and charitable contributions. We also incurred issuance costs of $0.7 million which were charged to additional paid-in capital. Branch Purchase – Bank of America On September 18, 2015, we completed our purchase of five branch-banking locations in southeastern Pennsylvania from Bank of America (BofA). The fair value of the acquired assets totaled $153.1 million , including $148.2 million in cash and $2.0 million in fixed and other assets. We also assumed $154.6 million in deposits associated with these branches. We paid a deposit premium of 1.96% and acquired an immaterial amount of loans as part of the transaction. Our operating results for 2015 include the impact of branch activity subsequent to the September 18, 2015 closing date. We recorded $1.5 million in goodwill and $3.0 million in core deposit intangibles as a result of the purchase transaction. The goodwill for this transaction is deductible for income tax purposes. Insurance Brokerage Purchases On June 22 and July 18, 2015, we, through our wholly-owned subsidiary, FNIA, acquired certain insurance-related assets from Pittsburgh-area insurance brokerage firms. Under the combined purchase agreements, we paid $3.4 million in cash and recorded goodwill of $1.8 million , other intangibles of $1.4 million and miscellaneous other assets of $0.2 million in connection with these acquisitions. The following table summarizes the amounts recorded on the consolidated balance sheets as of each of the acquisition dates in conjunction with the acquisitions discussed above: (in thousands) YDKN Fifth Third Branches METR BofA Branches Fair value of consideration paid $ 1,784,783 $ — $ 404,242 $ — Fair value of identifiable assets acquired: Cash and cash equivalents 196,964 198,872 46,890 148,159 Securities 940,272 — 722,980 — Loans 5,114,355 95,354 1,862,447 842 Core deposit and other intangible assets 69,555 4,129 24,163 3,000 Fixed and other assets 461,293 14,069 127,185 1,133 Total identifiable assets acquired 6,782,439 312,424 2,783,665 153,134 Fair value of liabilities assumed: Deposits 5,176,915 302,529 2,328,238 154,619 Borrowings 969,385 — 227,539 — Other liabilities 68,264 24,041 8,700 — Total liabilities assumed 6,214,564 326,570 2,564,477 154,619 Fair value of net identifiable assets acquired 567,875 (14,146 ) 219,188 (1,485 ) Goodwill recognized (1) $ 1,216,908 $ 14,146 $ 185,054 $ 1,485 (1) All of the goodwill for these transactions has been recorded in the Community Banking segment.

Securities

Securities	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Securities	SECURITIES The amortized cost and fair value of securities are as follows: (in thousands) Amortized Gross Unrealized Gains Gross Unrealized Losses Fair Value Securities Available for Sale (AFS): December 31, 2017 U.S. Treasury $ — $ — $ — $ — U.S. government-sponsored entities 347,767 52 (3,877 ) 343,942 Residential mortgage-backed securities: Agency mortgage-backed securities 1,615,168 1,225 (17,519 ) 1,598,874 Agency collateralized mortgage obligations 813,034 — (18,077 ) 794,957 Non-agency collateralized mortgage obligations 1 — — 1 Commercial mortgage-backed securities — — — — States of the U.S. and political subdivisions 21,151 6 (64 ) 21,093 Other debt securities 4,913 — (243 ) 4,670 Total debt securities 2,802,034 1,283 (39,780 ) 2,763,537 Equity securities 587 438 — 1,025 Total securities available for sale $ 2,802,621 $ 1,721 $ (39,780 ) $ 2,764,562 December 31, 2016 U.S. Treasury $ 29,874 $ 79 $ — $ 29,953 U.S. government-sponsored entities 367,604 864 (3,370 ) 365,098 Residential mortgage-backed securities: Agency mortgage-backed securities 1,267,535 2,257 (16,994 ) 1,252,798 Agency collateralized mortgage obligations 546,659 419 (11,104 ) 535,974 Non-agency collateralized mortgage obligations 891 6 — 897 Commercial mortgage-backed securities 1,292 — (1 ) 1,291 States of the U.S. and political subdivisions 36,065 86 (302 ) 35,849 Other debt securities 9,828 94 (435 ) 9,487 Total debt securities 2,259,748 3,805 (32,206 ) 2,231,347 Equity securities 273 367 — 640 Total securities available for sale $ 2,260,021 $ 4,172 $ (32,206 ) $ 2,231,987 (in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Securities Held to Maturity (HTM): December 31, 2017 U.S. Treasury $ 500 $ 134 $ — $ 634 U.S. government-sponsored entities 247,310 93 (4,388 ) 243,015 Residential mortgage-backed securities: Agency mortgage-backed securities 1,219,802 3,475 (9,058 ) 1,214,219 Agency collateralized mortgage obligations 777,146 32 (20,095 ) 757,083 Non-agency collateralized mortgage obligations — — — — Commercial mortgage-backed securities 80,786 414 (575 ) 80,625 States of the U.S. and political subdivisions 916,724 13,209 (7,130 ) 922,803 Total securities held to maturity $ 3,242,268 $ 17,357 $ (41,246 ) $ 3,218,379 December 31, 2016 U.S. Treasury $ 500 $ 137 $ — $ 637 U.S. government-sponsored entities 272,645 348 (4,475 ) 268,518 Residential mortgage-backed securities: Agency mortgage-backed securities 852,215 5,654 (8,645 ) 849,224 Agency collateralized mortgage obligations 743,148 447 (17,801 ) 725,794 Non-agency collateralized mortgage obligations 1,689 3 (6 ) 1,686 Commercial mortgage-backed securities 49,797 181 (226 ) 49,752 States of the U.S. and political subdivisions 417,348 1,456 (19,638 ) 399,166 Total securities held to maturity $ 2,337,342 $ 8,226 $ (50,791 ) $ 2,294,777 During 2017 , we received proceeds of $786.8 million from sales of AFS securities and realized a net gain of $3.7 million (gross gains of $4.7 million and gross losses of $1.0 million ). We also received proceeds of $57.1 million from sales of HTM securities with a net carrying value of $54.9 million and realized a net gain of $2.2 million (gross gains of $2.2 million and gross losses of $4,000 ). The HTM securities that were sold represented amortizing securities that had already returned more than 85% of their principal outstanding at the time we acquired the securities and could be sold without tainting the remaining HTM portfolio. Gross gains and gross losses were realized on securities as follows: Year Ended December 31 2017 2016 2015 (in thousands) Gross gains $ 6,866 $ 713 $ 831 Gross losses (950 ) (1 ) (9 ) Net gains $ 5,916 $ 712 $ 822 As of December 31, 2017 , the amortized cost and fair value of securities, by contractual maturities, were as follows: Available for Sale Held to Maturity (in thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 81,819 $ 81,594 $ 30,438 $ 30,254 Due from one to five years 278,153 274,516 225,054 220,921 Due from five to ten years 10,892 10,795 81,650 82,672 Due after ten years 2,967 2,800 827,392 832,605 373,831 369,705 1,164,534 1,166,452 Residential mortgage-backed securities: Agency mortgage-backed securities 1,615,168 1,598,874 1,219,802 1,214,219 Agency collateralized mortgage obligations 813,034 794,957 777,146 757,083 Non-agency collateralized mortgage obligations 1 1 — — Commercial mortgage-backed securities — — 80,786 80,625 Equity securities 587 1,025 — — Total securities $ 2,802,621 $ 2,764,562 $ 3,242,268 $ 3,218,379 Maturities may differ from contractual terms because borrowers may have the right to call or prepay obligations with or without penalties. Periodic payments are received on residential mortgage-backed securities based on the payment patterns of the underlying collateral. Following is information relating to securities pledged: December 31 2017 2016 (dollars in thousands) Securities pledged (carrying value): To secure public deposits, trust deposits and for other purposes as required by law $ 3,491,634 $ 2,779,335 As collateral for short-term borrowings 263,756 322,038 Securities pledged as a percent of total securities 62.5 % 67.9 % Following are summaries of the fair values and unrealized losses of temporarily impaired securities, segregated by length of impairment: Less than 12 Months 12 Months or More Total (dollars in thousands) # Fair Value Unrealized Losses # Fair Value Unrealized Losses # Fair Value Unrealized Losses Securities Available for Sale: December 31, 2017 U.S. government-sponsored entities 7 $ 106,809 $ (363 ) 10 $ 201,485 $ (3,514 ) 17 $ 308,294 $ (3,877 ) Residential mortgage-backed securities: Agency mortgage-backed securities 43 976,738 (7,723 ) 28 473,625 (9,796 ) 71 1,450,363 (17,519 ) Agency collateralized mortgage obligations 14 409,005 (6,231 ) 33 335,452 (11,846 ) 47 744,457 (18,077 ) Non-agency collateralized mortgage obligations — — — — — — — — — Commercial mortgage-backed securities — — — — — — — — — States of the U.S. and political subdivisions 7 11,254 (55 ) 1 879 (9 ) 8 12,133 (64 ) Other debt securities — — — 3 4,670 (243 ) 3 4,670 (243 ) Equity securities — — — — — — — — — Total temporarily impaired securities AFS 71 $ 1,503,806 $ (14,372 ) 75 $ 1,016,111 $ (25,408 ) 146 $ 2,519,917 $ (39,780 ) December 31, 2016 U.S. government-sponsored entities 11 $ 211,636 $ (3,370 ) — $ — $ — 11 $ 211,636 $ (3,370 ) Residential mortgage-backed securities: Agency mortgage-backed securities 55 1,056,731 (16,994 ) — — — 55 1,056,731 (16,994 ) Agency collateralized mortgage obligations 26 346,662 (7,261 ) 9 89,040 (3,843 ) 35 435,702 (11,104 ) Commercial mortgage-backed securities 1 1,291 (1 ) — — — 1 1,291 (1 ) States of the U.S. and political subdivisions 20 28,631 (302 ) — — — 20 28,631 (302 ) Other debt securities — — — 3 4,470 (435 ) 3 4,470 (435 ) Total temporarily impaired securities AFS 113 $ 1,644,951 $ (27,928 ) 12 $ 93,510 $ (4,278 ) 125 $ 1,738,461 $ (32,206 ) Less than 12 Months 12 Months or More Total (dollars in thousands) # Fair Value Unrealized Losses # Fair Value Unrealized Losses # Fair Value Unrealized Losses Securities Held to Maturity: December 31, 2017 U.S. government-sponsored entities 4 $ 54,790 $ (239 ) 10 $ 185,851 $ (4,149 ) 14 $ 240,641 $ (4,388 ) Residential mortgage-backed securities: Agency mortgage-backed securities 36 648,485 (4,855 ) 11 183,989 (4,203 ) 47 832,474 (9,058 ) Agency collateralized mortgage obligations 14 275,290 (1,701 ) 35 473,257 (18,394 ) 49 748,547 (20,095 ) Non-agency collateralized mortgage obligations — — — — — — — — — Commercial mortgage-backed securities 3 26,399 (123 ) 2 19,443 (452 ) 5 45,842 (575 ) States of the U.S. and political subdivisions 16 56,739 (933 ) 37 121,536 (6,197 ) 53 178,275 (7,130 ) Total temporarily impaired securities HTM 73 $ 1,061,703 $ (7,851 ) 95 $ 984,076 $ (33,395 ) 168 $ 2,045,779 $ (41,246 ) December 31, 2016 U.S. government-sponsored entities 10 $ 185,525 $ (4,475 ) — $ — $ — 10 $ 185,525 $ (4,475 ) Residential mortgage-backed securities: Agency mortgage-backed securities 36 551,404 (8,645 ) — — — 36 551,404 (8,645 ) Agency collateralized mortgage obligations 29 516,237 (13,710 ) 12 112,690 (4,091 ) 41 628,927 (17,801 ) Non-agency collateralized mortgage obligations 3 1,128 (6 ) — — — 3 1,128 (6 ) Commercial mortgage-backed securities 1 12,317 (10 ) 1 8,267 (216 ) 2 20,584 (226 ) States of the U.S. and political subdivisions 94 247,301 (19,638 ) — — — 94 247,301 (19,638 ) Total temporarily impaired securities HTM 173 $ 1,513,912 $ (46,484 ) 13 $ 120,957 $ (4,307 ) 186 $ 1,634,869 $ (50,791 ) We do not intend to sell the debt securities and it is not more likely than not that we will be required to sell the securities before recovery of their amortized cost basis. Other-Than-Temporary Impairment We evaluate our investment securities portfolio for OTTI on a quarterly basis. Impairment is assessed at the individual security level. We consider an investment security impaired if the fair value of the security is less than its cost or amortized cost basis. The following table presents a summary of the cumulative credit-related OTTI charges recognized as components of earnings for securities for which a portion of an OTTI is recognized in other comprehensive income: (in thousands) Equities Total For the Year Ended December 31, 2016 Beginning balance $ 27 $ 27 Loss where impairment was not previously recognized — — Additional loss where impairment was previously recognized — — Reduction due to credit impaired securities sold (27 ) (27 ) Ending balance $ — $ — We did not recognize any OTTI losses on securities for the years ended December 31, 2017 , 2016 and 2015 . States of the U.S. and Political Subdivisions Our municipal bond portfolio with a carrying amount of $937.8 million as of December 31, 2017 is highly rated with an average entity-specific rating of AA and 99% of the portfolio rated A or better. All of the securities in the municipal portfolio are general obligation bonds. Geographically, municipal bonds support our primary footprint as 65% of the securities are from municipalities located throughout Pennsylvania, Ohio, Maryland, North Carolina and South Carolina. The average holding size of the securities in the municipal bond portfolio is $3.0 million . In addition to the strong stand-alone ratings, 62% of the municipalities have some formal credit enhancement insurance that strengthens the creditworthiness of their issue. Management reviews the credit profile of each issuer on a quarterly basis.

Federal Home Loan Bank Stock

Federal Home Loan Bank Stock	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Federal Home Loan Bank Stock	FEDERAL HOME LOAN BANK STOCK We are a member of the Federal Home Loan Bank (FHLB) of Pittsburgh. The FHLB requires members to purchase and hold a specified minimum level of FHLB stock based upon their level of borrowings, collateral balances and participation in other programs offered by the FHLB. Stock in the FHLB is non-marketable and is redeemable at the discretion of the FHLB. Both cash and stock dividends on FHLB stock are reported as income. Members do not purchase stock in the FHLB for the same reasons that traditional equity investors acquire stock in an investor-owned enterprise. Rather, members purchase stock to obtain access to the low-cost products and services offered by the FHLB. Unlike equity securities of traditional for-profit enterprises, the stock of FHLB does not provide its holders with an opportunity for capital appreciation because, by regulation, FHLB stock can only be purchased, redeemed and transferred at par value. At December 31, 2017 and 2016 , our FHLB stock totaled $160.5 million and $85.0 million , respectively, and is included in other assets on the consolidated balance sheets. The increase in FHLB stock is a result of the YDKN acquisition. We account for the stock in accordance with ASC 325, which requires the investment to be carried at cost and evaluated for impairment based on the ultimate recoverability of the par value. Due to the regular quarterly dividends in 2016 and 2017, we believe our holdings in FHLB stock are ultimately recoverable at par value and, therefore, determined that the stock was not other-than-temporarily impaired. In addition, we have ample liquidity and do not require redemption of our FHLB stock in the foreseeable future.

Loans and Leases

Loans and Leases	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Loans and Leases	LOANS AND LEASES Following is a summary of loans and leases, net of unearned income: (in thousands) Originated Loans and Leases Acquired Loans Total Loans and Leases December 31, 2017 Commercial real estate $ 5,174,783 $ 3,567,081 $ 8,741,864 Commercial and industrial 3,495,247 675,420 4,170,667 Commercial leases 266,720 — 266,720 Other 17,063 — 17,063 Total commercial loans and leases 8,953,813 4,242,501 13,196,314 Direct installment 1,755,713 149,822 1,905,535 Residential mortgages 2,036,226 666,465 2,702,691 Indirect installment 1,448,268 165 1,448,433 Consumer lines of credit 1,151,470 594,323 1,745,793 Total consumer loans 6,391,677 1,410,775 7,802,452 Total loans and leases, net of unearned income $ 15,345,490 $ 5,653,276 $ 20,998,766 December 31, 2016 Commercial real estate $ 4,095,817 $ 1,339,345 $ 5,435,162 Commercial and industrial 2,711,886 330,895 3,042,781 Commercial leases 196,636 — 196,636 Other 35,878 — 35,878 Total commercial loans and leases 7,040,217 1,670,240 8,710,457 Direct installment 1,765,257 79,142 1,844,399 Residential mortgages 1,446,776 397,798 1,844,574 Indirect installment 1,196,110 203 1,196,313 Consumer lines of credit 1,099,627 201,573 1,301,200 Total consumer loans 5,507,770 678,716 6,186,486 Total loans and leases, net of unearned income $ 12,547,987 $ 2,348,956 $ 14,896,943 The loans and leases portfolio categories are comprised of the following: • Commercial real estate includes both owner-occupied and non-owner-occupied loans secured by commercial properties; • Commercial and industrial includes loans to businesses that are not secured by real estate; • Commercial leases consist of leases for new or used equipment; • Other is comprised primarily of credit cards and mezzanine loans; • Direct installment is comprised of fixed-rate, closed-end consumer loans for personal, family or household use, such as home equity loans and automobile loans; • Residential mortgages consist of conventional and jumbo mortgage loans for 1-4 family properties; • Indirect installment is comprised of loans originated by approved third parties and underwritten by us, primarily automobile loans; and • Consumer lines of credit include home equity lines of credit (HELOC) and consumer lines of credit that are either unsecured or secured by collateral other than home equity. The loans and leases portfolio consists principally of loans to individuals and small- and medium-sized businesses within our primary market areas of Pennsylvania, eastern Ohio, Maryland, North Carolina, South Carolina and northern West Virginia. The loans and leases portfolio also contains Regency consumer finance loans to individuals in Pennsylvania, Ohio, Tennessee and Kentucky. Due to the relative size of the Regency consumer finance loan portfolio, these loans are not segregated from other consumer loans. The following table shows certain information relating to the Regency consumer finance loans: December 31 2017 2016 (dollars in thousands) Regency consumer finance loans $ 174,916 $ 184,687 Percent of total loans and leases 0.8 % 1.2 % The following table shows certain information relating to commercial real estate loans: December 31 2017 2016 (dollars in thousands) Commercial construction, acquisition and development loans $ 1,170,175 $ 597,617 Percent of total loans and leases 5.6 % 4.0 % Commercial real estate: Percent owner-occupied 35.3 % 36.2 % Percent non-owner-occupied 64.7 % 63.8 % We have extended credit to certain directors and executive officers and their related interests. These related-party loans were made in the ordinary course of business under normal credit terms and do not involve more than a normal risk of collection. Following is a summary of the activity for these loans to related parties during 2017 : (in thousands) Balance at beginning of period $ 21,569 New loans 1,171 Repayments (3,447 ) Other 518 Balance at end of period $ 19,811 Other represents the net change in loan balances resulting from changes in related parties during 2017 . Acquired Loans All acquired loans were initially recorded at fair value at the acquisition date. Refer to the Acquired Loans section in Note 1, “Summary of Significant Accounting Policies,” for a discussion of ASC 310-20 and ASC 310-30 loans. The outstanding balance and the carrying amount of acquired loans included in the consolidated balance sheets are as follows: December 31 2017 2016 (in thousands) Accounted for under ASC 310-30: Outstanding balance $ 5,176,015 $ 2,346,687 Carrying amount 4,834,256 2,015,904 Accounted for under ASC 310-20: Outstanding balance 835,130 342,015 Carrying amount 812,322 325,784 Total acquired loans: Outstanding balance 6,011,145 2,688,702 Carrying amount 5,646,578 2,341,688 The outstanding balance is the undiscounted sum of all amounts owed under the loan, including amounts deemed principal, interest, fees, penalties and other, whether or not currently due and whether or not any such amounts have been written or charged-off. The carrying amount of purchased credit impaired loans included in the table above totaled $1.9 million at December 31, 2017 and $2.8 million at December 31, 2016 , representing 0.03% and 0.12% of the carrying amount of total acquired loans as of each date. The following table provides changes in accretable yield for all acquired loans accounted for under ASC 310-30. Loans accounted for under ASC 310-20 are not included in this table. Year Ended December 31 2017 2016 (in thousands) Balance at beginning of period $ 467,070 $ 256,120 Acquisitions 444,715 308,312 Reduction due to unexpected early payoffs (127,949 ) (86,046 ) Reclass from non-accretable difference 155,840 92,823 Disposals/transfers (3,559 ) (409 ) Other (658 ) — Accretion (226,978 ) (103,730 ) Balance at end of period $ 708,481 $ 467,070 Cash flows expected to be collected on acquired loans are estimated quarterly by incorporating several key assumptions similar to the initial estimate of fair value. These key assumptions include probability of default and the amount of actual prepayments after the acquisition date. Prepayments affect the estimated life of the loans and could change the amount of interest income, and possibly principal expected to be collected. In reforecasting future estimated cash flows, credit loss expectations are adjusted as necessary. Improved cash flow expectations for loans or pools are recorded first as a reversal of previously recorded impairment, if any, and then as an increase in prospective yield when all previously recorded impairment has been recaptured. Decreases in expected cash flows are recognized as impairment through a charge to the provision for credit losses and credit to the allowance for credit losses. During 2017 , there was an overall improvement in cash flow expectations which resulted in a net reclassification of $155.8 million from the non-accretable difference to accretable yield. This reclassification was $92.8 million for 2016 . The reclassification from the non-accretable difference to the accretable yield results in prospective yield adjustments on the loan pools. The following table reflects amounts at acquisition for all purchased loans subject to ASC 310-30 (impaired and non-impaired loans with deteriorated credit quality) acquired from YDKN in 2017 based on the fair value as described in Note 3. (in thousands) Acquired Impaired Loans Acquired Performing Loans Total Contractually required cash flows at acquisition $ 46,053 $ 5,085,712 $ 5,131,765 Non-accretable difference (expected losses and foregone interest) (23,924 ) (406,173 ) (430,097 ) Cash flows expected to be collected at acquisition 22,129 4,679,539 4,701,668 Accretable yield (3,266 ) (441,449 ) (444,715 ) Fair value of acquired loans at acquisition $ 18,863 $ 4,238,090 $ 4,256,953 In addition, loans purchased in the YDKN acquisition that were not subject to ASC 310-30 had the following balances at the date of acquisition: fair value of $778.4 million ; unpaid principal balance of $791.3 million ; and contractual cash flows not expected to be collected of $122.9 million . Credit Quality Management monitors the credit quality of our loan portfolio using several performance measures to do so based on payment activity and borrower performance. Non-performing loans include non-accrual loans and non-performing troubled debt restructurings (TDRs). Past due loans are reviewed on a monthly basis to identify loans for non-accrual status. We place originated loans on non-accrual status and discontinue interest accruals on originated loans generally when principal or interest is due and has remained unpaid for a certain number of days, or when the full amount of principal and interest is due and has remained unpaid for a certain number of days, unless the loan is both well secured and in the process of collection. Commercial loans are placed on non-accrual at 90 days, installment loans are placed on non-accrual at 120 days and residential mortgages and consumer lines of credit are generally placed on non-accrual at 180 days, though we may place a loan on non-accrual prior to these past due thresholds as warranted. When a loan is placed on non-accrual status, all unpaid accrued interest is reversed. Non-accrual loans may not be restored to accrual status until all delinquent principal and interest have been paid and the ultimate ability to collect the remaining principal and interest is reasonably assured. TDRs are loans in which we have granted a concession on the interest rate or the original repayment terms due to the borrower’s financial distress. Following is a summary of non-performing assets: December 31 2017 2016 (dollars in thousands) Non-accrual loans $ 74,635 $ 65,479 Troubled debt restructurings 23,481 20,428 Total non-performing loans 98,116 85,907 Other real estate owned (OREO) 40,606 32,490 Total non-performing assets $ 138,722 $ 118,397 Asset quality ratios: Non-performing loans / total loans and leases 0.47 % 0.58 % Non-performing loans + OREO / total loans and leases + OREO 0.66 % 0.79 % Non-performing assets / total assets 0.44 % 0.54 % The carrying value of residential other real estate owned (OREO) held as a result of obtaining physical possession upon completion of a foreclosure or through completion of a deed in lieu of foreclosure amounted to $3.6 million at December 31, 2017 . The recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process at December 31, 2017 and December 31, 2016 totaled $15.2 million and $12.0 million , respectively. The following tables provide an analysis of the aging of loans by class segregated by loans and leases originated and loans acquired: (in thousands) 30-89 Days Past Due ≥ 90 Days Past Due and Still Accruing Non- Accrual Total Past Due Current Total Loans and Leases Originated Loans and Leases December 31, 2017 Commercial real estate $ 8,273 $ 1 $ 24,773 $ 33,047 $ 5,141,736 $ 5,174,783 Commercial and industrial 8,948 3 17,077 26,028 3,469,219 3,495,247 Commercial leases 1,382 41 1,574 2,997 263,723 266,720 Other 83 153 1,000 1,236 15,827 17,063 Total commercial loans and leases 18,686 198 44,424 63,308 8,890,505 8,953,813 Direct installment 13,192 4,466 8,896 26,554 1,729,159 1,755,713 Residential mortgages 14,096 2,832 5,771 22,699 2,013,527 2,036,226 Indirect installment 10,313 611 2,240 13,164 1,435,104 1,448,268 Consumer lines of credit 5,859 1,014 2,313 9,186 1,142,284 1,151,470 Total consumer loans 43,460 8,923 19,220 71,603 6,320,074 6,391,677 Total originated loans and leases $ 62,146 $ 9,121 $ 63,644 $ 134,911 $ 15,210,579 $ 15,345,490 December 31, 2016 Commercial real estate $ 8,452 $ 1 $ 20,114 $ 28,567 $ 4,067,250 $ 4,095,817 Commercial and industrial 16,019 3 24,141 40,163 2,671,723 2,711,886 Commercial leases 973 1 3,429 4,403 192,233 196,636 Other 398 83 1,000 1,481 34,397 35,878 Total commercial loans and leases 25,842 88 48,684 74,614 6,965,603 7,040,217 Direct installment 10,573 4,386 6,484 21,443 1,743,814 1,765,257 Residential mortgages 10,594 3,014 3,316 16,924 1,429,852 1,446,776 Indirect installment 9,312 513 1,983 11,808 1,184,302 1,196,110 Consumer lines of credit 3,529 1,112 1,616 6,257 1,093,370 1,099,627 Total consumer loans 34,008 9,025 13,399 56,432 5,451,338 5,507,770 Total originated loans and leases $ 59,850 $ 9,113 $ 62,083 $ 131,046 $ 12,416,941 $ 12,547,987 (in thousands) 30-89 Days Past Due ≥ 90 Days Past Due and Still Accruing Non- Accrual Total Past Due (1)(2) Current (Discount)/ Premium Total Loans Acquired Loans December 31, 2017 Commercial real estate $ 34,928 $ 63,092 $ 3,975 $ 101,995 $ 3,657,152 $ (192,066 ) $ 3,567,081 Commercial and industrial 3,187 6,452 5,663 15,302 698,265 (38,147 ) 675,420 Total commercial loans 38,115 69,544 9,638 117,297 4,355,417 (230,213 ) 4,242,501 Direct installment 5,267 2,013 — 7,280 141,386 1,156 149,822 Residential mortgages 17,191 15,139 — 32,330 675,499 (41,364 ) 666,465 Indirect installment — 1 — 1 10 154 165 Consumer lines of credit 6,353 3,253 1,353 10,959 596,298 (12,934 ) 594,323 Total consumer loans 28,811 20,406 1,353 50,570 1,413,193 (52,988 ) 1,410,775 Total acquired loans $ 66,926 $ 89,950 $ 10,991 $ 167,867 $ 5,768,610 $ (283,201 ) $ 5,653,276 December 31, 2016 Commercial real estate $ 9,501 $ 23,890 $ 949 $ 34,340 $ 1,384,752 $ (79,747 ) $ 1,339,345 Commercial and industrial 1,789 2,942 2,111 6,842 353,494 (29,441 ) 330,895 Total commercial loans 11,290 26,832 3,060 41,182 1,738,246 (109,188 ) 1,670,240 Direct installment 2,317 1,344 — 3,661 73,479 2,002 79,142 Residential mortgages 8,428 10,816 — 19,244 416,561 (38,007 ) 397,798 Indirect installment 19 4 — 23 96 84 203 Consumer lines of credit 2,156 1,528 336 4,020 201,958 (4,405 ) 201,573 Total consumer loans 12,920 13,692 336 26,948 692,094 (40,326 ) 678,716 Total acquired loans $ 24,210 $ 40,524 $ 3,396 $ 68,130 $ 2,430,340 $ (149,514 ) $ 2,348,956 (1) Past due information for acquired loans is based on the contractual balance outstanding at December 31, 2017 and 2016 . (2) Acquired loans are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of expected cash flows on such loans. In these instances, we do not consider acquired contractually delinquent loans to be non-accrual or non-performing and continue to recognize interest income on these loans using the accretion method. Acquired loans are considered non-accrual or non-performing when, due to credit deterioration or other factors, we determine we are no longer able to reasonably estimate the timing and amount of expected cash flows on such loans. We do not recognize interest income on acquired loans considered non-accrual or non-performing. We utilize the following categories to monitor credit quality within our commercial loan and lease portfolio: Rating Category Definition Pass in general, the condition of the borrower and the performance of the loan is satisfactory or better Special Mention in general, the condition of the borrower has deteriorated, requiring an increased level of monitoring Substandard in general, the condition of the borrower has significantly deteriorated and the performance of the loan could further deteriorate if deficiencies are not corrected Doubtful in general, the condition of the borrower has significantly deteriorated and the collection in full of both principal and interest is highly questionable or improbable The use of these internally assigned credit quality categories within the commercial loan and lease portfolio permits management’s use of transition matrices to estimate a quantitative portion of credit risk. Our internal credit risk grading system is based on past experiences with similarly graded loans and leases and conforms with regulatory categories. In general, loan and lease risk ratings within each category are reviewed on an ongoing basis according to our policy for each class of loans and leases. Each quarter, management analyzes the resulting ratings, as well as other external statistics and factors such as delinquency, to track the migration performance of the commercial loan and lease portfolio. Loans and leases within the Pass credit category or that migrate toward the Pass credit category generally have a lower risk of loss compared to loans and leases that migrate toward the Substandard or Doubtful credit categories. Accordingly, management applies higher risk factors to Substandard and Doubtful credit categories. The following tables present a summary of our commercial loans and leases by credit quality category segregated by loans and leases originated and loans acquired: Commercial Loan and Lease Credit Quality Categories (in thousands) Pass Special Mention Substandard Doubtful Total Originated Loans and Leases December 31, 2017 Commercial real estate $ 4,922,872 $ 152,744 $ 98,728 $ 439 $ 5,174,783 Commercial and industrial 3,266,966 132,975 92,091 3,215 3,495,247 Commercial leases 260,235 4,425 2,060 — 266,720 Other 15,866 43 1,154 — 17,063 Total originated commercial loans and leases $ 8,465,939 $ 290,187 $ 194,033 $ 3,654 $ 8,953,813 December 31, 2016 Commercial real estate $ 3,895,764 $ 130,452 $ 69,588 $ 13 $ 4,095,817 Commercial and industrial 2,475,955 104,652 128,089 3,190 2,711,886 Commercial leases 188,662 3,789 4,185 — 196,636 Other 34,531 264 1,083 — 35,878 Total originated commercial loans and leases $ 6,594,912 $ 239,157 $ 202,945 $ 3,203 $ 7,040,217 Acquired Loans December 31, 2017 Commercial real estate $ 3,102,788 $ 250,987 $ 213,089 $ 217 $ 3,567,081 Commercial and industrial 603,611 26,059 45,661 89 675,420 Total acquired commercial loans $ 3,706,399 $ 277,046 $ 258,750 $ 306 $ 4,242,501 December 31, 2016 Commercial real estate $ 1,144,676 $ 85,894 $ 108,128 $ 647 $ 1,339,345 Commercial and industrial 274,819 20,593 34,967 516 330,895 Total acquired commercial loans $ 1,419,495 $ 106,487 $ 143,095 $ 1,163 $ 1,670,240 Credit quality information for acquired loans is based on the contractual balance outstanding at December 31, 2017 and 2016 . We use delinquency transition matrices within the consumer and other loan classes to enable management to estimate a quantitative portion of credit risk. Each month, management analyzes payment and volume activity, FICO scores and other external factors such as unemployment, to determine how consumer loans are performing. Following is a table showing consumer loans by payment status: Consumer Loan Credit Quality by Payment Status (in thousands) Performing Non-Performing Total Originated loans December 31, 2017 Direct installment $ 1,739,060 $ 16,653 $ 1,755,713 Residential mortgages 2,019,816 16,410 2,036,226 Indirect installment 1,445,833 2,435 1,448,268 Consumer lines of credit 1,147,576 3,894 1,151,470 Total originated consumer loans $ 6,352,285 $ 39,392 $ 6,391,677 December 31, 2016 Direct installment $ 1,750,305 $ 14,952 $ 1,765,257 Residential mortgages 1,433,409 13,367 1,446,776 Indirect installment 1,193,930 2,180 1,196,110 Consumer lines of credit 1,096,642 2,985 1,099,627 Total originated consumer loans $ 5,474,286 $ 33,484 $ 5,507,770 Acquired loans December 31, 2017 Direct installment $ 149,751 $ 71 $ 149,822 Residential mortgages 666,465 — 666,465 Indirect installment 165 — 165 Consumer lines of credit 592,384 1,939 594,323 Total acquired consumer loans $ 1,408,765 $ 2,010 $ 1,410,775 December 31, 2016 Direct installment $ 79,142 $ — $ 79,142 Residential mortgages 397,798 — 397,798 Indirect installment 203 — 203 Consumer lines of credit 201,061 512 201,573 Total acquired consumer loans $ 678,204 $ 512 $ 678,716 Loans and leases are designated as impaired when, in the opinion of management, based on current information and events, the collection of principal and interest in accordance with the loan and lease contract is doubtful. Typically, we do not consider loans and leases for impairment unless a sustained period of delinquency (i.e., 90 -plus days) is noted or there are subsequent events that impact repayment probability (i.e., negative financial trends, bankruptcy filings, imminent foreclosure proceedings, etc.). Impairment is evaluated in the aggregate for consumer installment loans, residential mortgages, consumer lines of credit and commercial loan and lease relationships less than $500,000 based on loan and lease segment loss given default. For commercial loan and lease relationships greater than or equal to $500,000 , a specific valuation allowance is allocated, if necessary, so that the loan is reported net, at the present value of estimated future cash flows using a market interest rate or at the fair value of collateral if repayment is expected solely from the collateral. Consistent with our existing method of income recognition for loans and leases, interest income on impaired loans, except those classified as non-accrual, is recognized using the accrual method. Impaired loans, or portions thereof, are charged off when deemed uncollectible. Following is a summary of information pertaining to originated loans and leases considered to be impaired, by class of loan and lease: (in thousands) Unpaid Contractual Principal Balance Recorded Investment With No Specific Reserve Recorded Investment With Specific Reserve Total Recorded Investment Specific Reserve Average Recorded Investment At or for the Year Ended Commercial real estate $ 27,718 $ 21,748 $ 2,906 $ 24,654 $ 439 $ 24,413 Commercial and industrial 29,307 11,595 4,457 16,052 3,215 23,907 Commercial leases 1,574 1,574 — 1,574 — 1,386 Other — — — — — — Total commercial loans and leases 58,599 34,917 7,363 42,280 3,654 49,706 Direct installment 19,375 16,653 — 16,653 — 16,852 Residential mortgages 17,754 16,410 — 16,410 — 15,984 Indirect installment 5,709 2,435 — 2,435 — 2,279 Consumer lines of credit 5,039 3,894 — 3,894 — 3,815 Total consumer loans 47,877 39,392 — 39,392 — 38,930 Total $ 106,476 $ 74,309 $ 7,363 $ 81,672 $ 3,654 $ 88,636 At or for the Year Ended Commercial real estate $ 23,771 $ 19,699 $ 464 $ 20,163 $ 13 $ 19,217 Commercial and industrial 25,719 14,781 8,996 23,777 3,190 29,730 Commercial leases 3,429 3,429 — 3,429 — 3,394 Other 1,000 1,000 — 1,000 — 1,000 Total commercial loans and leases 53,919 38,909 9,460 48,369 3,203 53,341 Direct installment 16,440 14,952 — 14,952 — 14,997 Residential mortgages 14,090 13,367 — 13,367 — 13,200 Indirect installment 5,172 2,180 — 2,180 — 2,037 Consumer lines of credit 3,858 2,985 — 2,985 — 2,813 Total consumer loans 39,560 33,484 — 33,484 — 33,047 Total $ 93,479 $ 72,393 $ 9,460 $ 81,853 $ 3,203 $ 86,388 Interest income continued to accrue on certain impaired loans and totaled approximately $6.1 million , $4.6 million and $4.1 million during 2017 , 2016 and 2015 , respectively. The above tables do not reflect the additional allowance for credit losses relating to acquired loans. Following is a summary of the allowance for credit losses required for acquired loans due to changes in credit quality subsequent to the acquisition date: December 31 2017 2016 (in thousands) Commercial real estate $ 4,976 $ 4,538 Commercial and industrial (415 ) 500 Total commercial loans 4,561 5,038 Direct installment 1,553 1,005 Residential mortgages 484 632 Indirect installment 177 221 Consumer lines of credit (77 ) 372 Total consumer loans 2,137 2,230 Total allowance on acquired loans $ 6,698 $ 7,268 Troubled Debt Restructurings TDRs are loans whose contractual terms have been modified in a manner that grants a concession to a borrower experiencing financial difficulties. TDRs typically result from loss mitigation activities and could include the extension of a maturity date, interest rate reduction, principal forgiveness, deferral or decrease in payments for a period of time and other actions intended to minimize the economic loss and to avoid foreclosure or repossession of collateral. Following is a summary of the composition of total TDRs: (in thousands) Originated Acquired Total December 31, 2017 Accruing: Performing $ 19,538 $ 266 $ 19,804 Non-performing 20,173 3,308 23,481 Non-accrual 10,472 234 10,706 Total TDRs $ 50,183 $ 3,808 $ 53,991 December 31, 2016 Accruing: Performing $ 17,105 $ 365 $ 17,470 Non-performing 20,252 176 20,428 Non-accrual 9,035 — 9,035 Total TDRs $ 46,392 $ 541 $ 46,933 TDRs that are accruing and performing include loans that met the criteria for non-accrual of interest prior to restructuring for which we can reasonably estimate the timing and amount of the expected cash flows on such loans and for which we expect to fully collect the new carrying value of the loans. During 2017 , we returned to performing status $3.9 million in restructured residential mortgage loans that have consistently met their modified obligations for more than six months. TDRs that are accruing and non-performing are comprised of consumer loans that have not demonstrated a consistent repayment pattern on the modified terms for more than nine months, however it is expected that we will collect all future principal and interest payments. TDRs that are on non-accrual are not placed on accruing status until all delinquent principal and interest have been paid and the ultimate collectability of the remaining principal and interest is reasonably assured. Some loan modifications classified as TDRs may not ultimately result in the full collection of principal and interest, as modified, and may result in potential incremental losses which are factored into the allowance for credit losses. Excluding purchased impaired loans, commercial loans over $500,000 whose terms have been modified in a TDR are generally placed on non-accrual, individually analyzed and measured for estimated impairment based on the fair value of the underlying collateral. Our allowance for credit losses included specific reserves for commercial TDRs and pooled reserves for individual loans under $500,000 based on loan segment loss given default. Upon default, the amount of the recorded investment in the TDR in excess of the fair value of the collateral, less estimated selling costs, is generally considered a confirmed loss and is charged-off against the allowance for credit losses. The reserve for commercial TDRs included in the allowance for credit losses is presented in the following table: December 31 2017 2016 (in thousands) Specific reserves for commercial TDRs $ 95 $ 291 Pooled reserves for individual commercial loans under $500 469 276 All other classes of loans, which are primarily secured by residential properties whose terms have been modified in a TDR are pooled and measured for estimated impairment based on the expected net present value of the estimated future cash flows of the pool. Our allowance for credit losses included pooled reserves for these classes of loans of $4.0 million and $3.7 million at December 31, 2017 and 2016 , respectively. Upon default of an individual loan, our charge-off policy is followed accordingly for that class of loan. The majority of TDRs are the result of interest rate concessions for a limited period of time. Following is a summary of loans, by class, that have been restructured: Year Ended December 31 2017 2016 (dollars in thousands) Number of Contracts Pre-Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Number of Contracts Pre-Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Commercial real estate 3 $ 1,608 $ 1,683 4 $ 778 $ 737 Commercial and industrial 3 3,568 3,091 3 1,727 1,504 Total commercial loans 6 5,176 4,774 7 2,505 2,241 Direct installment 641 5,107 4,500 527 6,090 5,566 Residential mortgages 43 2,251 2,095 45 2,155 2,081 Indirect installment 18 48 43 19 51 51 Consumer lines of credit 64 1,372 1,158 81 1,419 1,283 Total consumer loans 766 8,778 7,796 672 9,715 8,981 Total 772 $ 13,954 $ 12,570 679 $ 12,220 $ 11,222 Following is a summary of originated TDRs, by class, for which there was a payment default, excluding loans that were either charged-off or cured by period end. Default occurs when a loan is 90 days or more past due and is within 12 months of restructuring. Year Ended December 31 2017 2016 (dollars in thousands) Number of Contracts Recorded Investment Number of Contracts Recorded Investment Commercial real estate 1 $ 463 — $ — Commercial and industrial — — — — Total commercial loans 1 463 — — Direct installment 131 358 90 313 Residential mortgages 6 314 7 285 Indirect installment 17 28 18 35 Consumer lines of credit 5 170 3 394 Total consumer loans 159 870 118 1,027 Total 160 $ 1,333 118 $ 1,027

Allowance for Credit Losses

Allowance for Credit Losses	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Allowance for Credit Losses	ALLOWANCE FOR CREDIT LOSSES Following is a summary of changes in the allowance for credit losses, by loan and lease class: (in thousands) Balance at Beginning of Year Charge- Offs Recoveries Net Charge- Offs Provision for Credit Losses Balance at End of Year Year Ended December 31, 2017 Commercial real estate $ 46,635 $ (2,178 ) $ 2,311 $ 133 $ 3,513 $ 50,281 Commercial and industrial 47,991 (26,188 ) 1,275 (24,913 ) 28,885 51,963 Commercial leases 3,280 (1,017 ) 6 (1,011 ) 3,377 5,646 Other 1,392 (4,099 ) 1,255 (2,844 ) 3,295 1,843 Total commercial loans and leases 99,298 (33,482 ) 4,847 (28,635 ) 39,070 109,733 Direct installment 21,391 (12,401 ) 2,015 (10,386 ) 9,931 20,936 Residential mortgages 10,082 (595 ) 184 (411 ) 5,836 15,507 Indirect installment 10,564 (9,201 ) 3,708 (5,493 ) 6,896 11,967 Consumer lines of credit 9,456 (2,204 ) 461 (1,743 ) 2,826 10,539 Total consumer loans 51,493 (24,401 ) 6,368 (18,033 ) 25,489 58,949 Total allowance on originated loans 150,791 (57,883 ) 11,215 (46,668 ) 64,559 168,682 Purchased credit-impaired loans 572 (469 ) 36 (433 ) 496 635 Other acquired loans 6,696 (1,233 ) 4,582 3,349 (3,982 ) 6,063 Total allowance on acquired loans 7,268 (1,702 ) 4,618 2,916 (3,486 ) 6,698 Total allowance $ 158,059 $ (59,585 ) $ 15,833 $ (43,752 ) $ 61,073 $ 175,380 Year Ended December 31, 2016 Commercial real estate $ 41,741 $ (6,657 ) $ 3,669 $ (2,988 ) $ 7,882 $ 46,635 Commercial and industrial 41,023 (19,584 ) 2,508 (17,076 ) 24,044 47,991 Commercial leases 2,541 (962 ) 66 (896 ) 1,635 3,280 Other 1,013 (2,729 ) 131 (2,598 ) 2,977 1,392 Total commercial loans and leases 86,318 (29,932 ) 6,374 (23,558 ) 36,538 99,298 Direct installment 21,587 (10,153 ) 1,822 (8,331 ) 8,135 21,391 Residential mortgages 7,909 (441 ) 74 (367 ) 2,540 10,082 Indirect installment 9,889 (7,855 ) 2,015 (5,840 ) 6,515 10,564 Consumer lines of credit 9,582 (2,085 ) 265 (1,820 ) 1,694 9,456 Total consumer loans 48,967 (20,534 ) 4,176 (16,358 ) 18,884 51,493 Total allowance on originated loans 135,285 (50,466 ) 10,550 (39,916 ) 55,422 150,791 Purchased credit-impaired loans 834 (399 ) 42 (357 ) 95 572 Other acquired loans 5,893 (649 ) 1,217 568 235 6,696 Total allowance on acquired loans 6,727 (1,048 ) 1,259 211 330 7,268 Total allowance $ 142,012 $ (51,514 ) $ 11,809 $ (39,705 ) $ 55,752 $ 158,059 Year Ended December 31, 2015 Commercial real estate $ 37,588 $ (4,443 ) $ 1,117 $ (3,326 ) $ 7,479 $ 41,741 Commercial and industrial 32,645 (3,562 ) 1,773 (1,789 ) 10,167 41,023 Commercial leases 2,398 (544 ) 101 (443 ) 586 2,541 Other 759 (1,691 ) 55 (1,636 ) 1,890 1,013 Total commercial loans and leases 73,390 (10,240 ) 3,046 (7,194 ) 20,122 86,318 Direct installment 20,538 (10,844 ) 1,527 (9,317 ) 10,366 21,587 Residential mortgages 8,024 (1,010 ) 85 (925 ) 810 7,909 Indirect installment 7,504 (6,427 ) 1,190 (5,237 ) 7,622 9,889 Consumer lines of credit 8,496 (1,653 ) 175 (1,478 ) 2,564 9,582 Total consumer loans 44,562 (19,934 ) 2,977 (16,957 ) 21,362 48,967 Total allowance on originated loans 117,952 (30,174 ) 6,023 (24,151 ) 41,484 135,285 Purchased credit-impaired loans 660 (64 ) 19 (45 ) 219 834 Other acquired loans 7,314 (830 ) 671 (159 ) (1,262 ) 5,893 Total allowance on acquired loans 7,974 (894 ) 690 (204 ) (1,043 ) 6,727 Total allowance $ 125,926 $ (31,068 ) $ 6,713 $ (24,355 ) $ 40,441 $ 142,012 Following is a summary of the individual and collective originated allowance for credit losses and corresponding originated loan and lease balances by class: Originated Allowance Originated Loans and Leases Outstanding (in thousands) Individually Evaluated for Impairment Collectively Evaluated for Impairment Loans and Leases Individually Evaluated for Impairment Collectively Evaluated for Impairment December 31, 2017 Commercial real estate $ 439 $ 49,842 $ 5,174,783 $ 11,114 $ 5,163,669 Commercial and industrial 3,215 48,748 3,495,247 9,872 3,485,375 Commercial leases — 5,646 266,720 — 266,720 Other — 1,843 17,063 — 17,063 Total commercial loans and leases 3,654 106,079 8,953,813 20,986 8,932,827 Direct installment — 20,936 1,755,713 — 1,755,713 Residential mortgages — 15,507 2,036,226 — 2,036,226 Indirect installment — 11,967 1,448,268 — 1,448,268 Consumer lines of credit — 10,539 1,151,470 — 1,151,470 Total consumer loans — 58,949 6,391,677 — 6,391,677 Total $ 3,654 $ 165,028 $ 15,345,490 $ 20,986 $ 15,324,504 December 31, 2016 Commercial real estate $ 13 $ 46,622 $ 4,095,817 $ 12,973 $ 4,082,844 Commercial and industrial 3,190 44,801 2,711,886 21,746 2,690,140 Commercial leases — 3,280 196,636 — 196,636 Other — 1,392 35,878 — 35,878 Total commercial loans and leases 3,203 96,095 7,040,217 34,719 7,005,498 Direct installment — 21,391 1,765,257 — 1,765,257 Residential mortgages — 10,082 1,446,776 — 1,446,776 Indirect installment — 10,564 1,196,110 — 1,196,110 Consumer lines of credit — 9,456 1,099,627 — 1,099,627 Total consumer loans — 51,493 5,507,770 — 5,507,770 Total $ 3,203 $ 147,588 $ 12,547,987 $ 34,719 $ 12,513,268 The above table excludes acquired loans that were pooled into groups of loans for evaluating impairment.

Loan Servicing

Loan Servicing	12 Months Ended
	Dec. 31, 2017
Transfers and Servicing [Abstract]
Loan Servicing	LOAN SERVICING Mortgage Loan Servicing We retain the servicing rights on certain mortgage loans sold. The unpaid principal balance of mortgage loans serviced for others, as of December 31, 2017 and 2016 , is listed below: December 31 2017 2016 (in thousands) Mortgage loans sold with servicing retained $ 3,256,548 $ 1,800,002 The following table summarizes activity relating to mortgage loans sold with servicing retained: Year Ended December 31 2017 2016 2015 (in thousands) Mortgage loans sold with servicing retained $ 1,769,129 $ 672,536 $ 431,617 Pretax gains resulting from above loan sales (1) 21,683 12,519 10,681 Mortgage servicing fees (1) 7,509 3,803 3,056 (1) Recorded in mortgage banking operations. Following is a summary of the MSR activity: Year Ended December 31 2017 2016 2015 (in thousands) Balance at beginning of period $ 13,521 $ 8,921 $ 6,859 Fair value of MSRs acquired 8,553 — — Additions 10,830 7,148 3,370 Payoffs and curtailments (1,491 ) (780 ) (694 ) Amortization (2,360 ) (1,768 ) (614 ) Balance at end of period $ 29,053 $ 13,521 $ 8,921 Fair value, beginning of period $ 17,546 $ 11,503 $ 8,684 Fair value, end of period 32,419 17,546 11,503 We did not have a valuation allowance for MSRs for any of the periods presented in the table above. The fair value of MSRs is highly sensitive to changes in assumptions and is determined by estimating the present value of the asset’s future cash flows utilizing market-based prepayment rates, discount rates and other assumptions validated through comparison to trade information, industry surveys and with the use of independent third party appraisals. Changes in prepayment speed assumptions have the most significant impact on the fair value of MSRs. Generally, as interest rates decline, mortgage loan prepayments accelerate due to increased refinance activity, which results in a decrease in the fair value of the MSR. Measurement of fair value is limited to the conditions existing and the assumptions utilized as of a particular point in time, and those assumptions may not be appropriate if they are applied at a different time. Following is a summary of the sensitivity of the fair value of MSRs to changes in key assumptions: December 31 2017 2016 (dollars in thousands) Weighted average life (months) 80.4 79.0 Constant prepayment rate (annualized) 9.9 % 9.9 % Discount rate 9.9 % 9.8 % Effect on fair value due to change in interest rates: +0.25% $ 1,737 $ 692 +0.50% 3,220 1,288 -0.25% (1,937 ) (789 ) -0.50% (4,007 ) (1,680 ) The sensitivity calculations above are hypothetical and should not be considered to be predictive of future performance. Changes in fair value based on adverse changes in assumptions generally cannot be extrapolated because the relationship of the changes in assumptions to fair value may not be linear. Also, in this table, the effects of an adverse variation in a particular assumption on the fair value of the MSRs is calculated without changing any other assumptions, while in reality, changes in one factor may result in changing another, which may magnify or contract the effect of the change. SBA-Guaranteed Loan Servicing Beginning in March 2017, as a result of the YDKN acquisition, we retain the servicing rights on SBA-guaranteed loans sold to investors. The standard sale structure under the SBA Secondary Participation Guaranty Agreement provides for us to retain a portion of the cash flow from the interest payment received on the loan, which is commonly known as a servicing spread. The unpaid principal balance of SBA-guaranteed loans serviced for investors, as of December 31, 2017 , was as follows: December 31 2017 (in thousands) SBA loans sold to investors with servicing retained $ 305,977 The following table summarizes activity relating to SBA loans sold with servicing retained: Year Ended December 31 2017 (in thousands) SBA loans sold with servicing retained $ 53,938 Pretax gains resulting from above loan sales (1) 2,247 SBA servicing fees (1) 2,195 (1) Recorded in non-interest income. Following is a summary of the activity in SBA servicing assets: Year Ended December 31 2017 (in thousands) Balance at beginning of period $ — Fair value of servicing rights acquired 5,399 Additions 959 Impairment (charge) / recovery (281 ) Amortization (1,019 ) Balance at end of period $ 5,058 Fair value, beginning of period $ — Fair value, end of period 5,058 Following is a summary of key assumptions and the sensitivity of the SBA loan servicing rights to changes in these assumptions: December 31 2017 Decline in fair value due to (dollars in thousands) Actual 10% adverse change 20% adverse change 1% adverse change 2% adverse change Weighted-average life (months) 63.5 Constant prepayment rate 9.29 % $ (145 ) $ (284 ) $ — $ — Discount rate 14.87 — — (147 ) (286 ) The fair value of the SBA servicing assets is compared to the amortized basis when certain triggering events occur. If the amortized basis exceeds the fair value, the asset is considered impaired and is written down to fair value through a valuation allowance on the asset and a charge against SBA income. We had a $0.3 million valuation allowance for SBA servicing assets as of December 31, 2017 .

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Premises and Equipment	PREMISES AND EQUIPMENT Following is a summary of premises and equipment: December 31 2017 2016 (in thousands) Land $ 67,424 $ 45,640 Premises 239,807 186,784 Equipment 212,587 174,325 519,818 406,749 Accumulated depreciation (183,278 ) (162,793 ) Total premises and equipment, net $ 336,540 $ 243,956 Depreciation expense for premises and equipment is presented in the following table: December 31 2017 2016 2015 (in thousands) Depreciation expense for premises and equipment $ 34,322 $ 23,355 $ 20,009 We have operating leases extending to 2046 for certain land, office locations and equipment, many of which have renewal options. Leases that expire are generally expected to be replaced by other leases. Lease costs are expensed in accordance with ASC 840, Leases , taking into account escalation clauses. Rental expense is presented in the following table: December 31 2017 2016 2015 (in thousands) Rental expense $ 29,148 $ 21,015 $ 16,193 Following is a summary of future minimum lease payments for years following December 31, 2017 : (in thousands) 2018 $ 26,949 2019 22,995 2020 18,587 2021 15,358 2022 11,855 Later years 49,342 Total minimum rental commitment under leases $ 145,086

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS The following table shows a rollforward of goodwill by line of business: (in thousands) Community Banking Wealth Manage- ment Insurance Consumer Finance Total Balance at January 1, 2016 $ 812,399 $ 8,020 $ 10,858 $ 1,809 $ 833,086 Goodwill (deductions) additions 199,200 — (157 ) — 199,043 Balance at December 31, 2016 1,011,599 8,020 10,701 1,809 1,032,129 Goodwill (deductions) additions 1,216,908 151 — — 1,217,059 Balance at December 31, 2017 $ 2,228,507 $ 8,171 $ 10,701 $ 1,809 $ 2,249,188 We recorded goodwill during 2016 and 2017 as a result of the purchase accounting adjustments relating to the various acquisitions described in Note 3, “Mergers and Acquisitions.” The following table shows a summary of core deposit intangibles and customer renewal lists: (in thousands) Core Deposit Intangibles Customer Renewal Lists Total December 31, 2017 Gross carrying amount $ 195,582 $ 12,442 $ 208,024 Accumulated amortization (106,938 ) (9,011 ) (115,949 ) Net carrying amount $ 88,644 $ 3,431 $ 92,075 December 31, 2016 Gross carrying amount $ 139,886 $ 12,352 $ 152,238 Accumulated amortization (89,888 ) (8,544 ) (98,432 ) Net carrying amount $ 49,998 $ 3,808 $ 53,806 Core deposit intangibles are being amortized primarily over 10 years using accelerated methods. Customer renewal lists are being amortized over their estimated useful lives, which range from eight to thirteen years. The following table summarizes amortization expense recognized: December 31 2017 2016 2015 (in thousands) Amortization expense $ 17,517 $ 11,210 $ 8,305 Following is a summary of the expected amortization expense on finite-lived intangible assets, assuming no new additions, for each of the five years following December 31, 2017 : (in thousands) 2018 $ 15,633 2019 13,532 2020 12,503 2021 11,339 2022 9,637 Total $ 62,644 Goodwill and other intangible assets are tested annually for impairment, and more frequently if events or changes in circumstances indicate the carrying value may not be recoverable. We completed this test in 2017 and 2016 and determined that our intangible assets are not impaired.

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Deposits	DEPOSITS Following is a summary of deposits: December 31 2017 2016 (in thousands) Non-interest-bearing demand $ 5,720,030 $ 4,205,337 Interest-bearing demand 9,571,038 6,931,381 Savings 2,488,178 2,352,434 Certificates and other time deposits: Less than $100,000 2,461,014 1,680,068 $100,000 through $250,000 1,326,562 642,509 Greater than $250,000 832,903 253,918 Total deposits $ 22,399,725 $ 16,065,647 Following is a summary of the scheduled maturities of certificates and other time deposits for the years following December 31, 2017 : (in thousands) 2018 $ 2,778,467 2019 1,026,222 2020 351,431 2021 194,678 2022 118,891 Later years 150,790 Total $ 4,620,479

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Short-Term Borrowings	SHORT-TERM BORROWINGS Following is a summary of short-term borrowings: December 31 2017 2016 (in thousands) Securities sold under repurchase agreements $ 256,017 $ 313,062 Federal Home Loan Bank advances 2,285,000 1,025,000 Federal funds purchased 1,000,000 1,037,000 Subordinated notes 137,320 127,948 Total short-term borrowings $ 3,678,337 $ 2,503,010 Borrowings with original maturities of one year or less are classified as short-term. Securities sold under repurchase agreements are comprised of customer repurchase agreements, which are sweep accounts with next-day maturities utilized by larger commercial customers to earn interest on their funds. Securities are pledged to these customers in an amount equal to the outstanding balance. The following represents weighted average interest rates on short-term borrowings: December 31 2017 2016 2015 Year-to-date average 1.16 % 0.61 % 0.42 % Period-end 1.44 % 0.69 % 0.48 %

Long-Term Borrowings

Long-Term Borrowings	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Long-Term Borrowings	LONG-TERM BORROWINGS Following is a summary of long-term borrowings: December 31 2017 2016 (in thousands) Federal Home Loan Bank advances $ 310,061 $ 305,110 Subordinated notes 87,614 87,147 Junior subordinated debt 110,347 48,600 Other subordinated debt 160,151 98,637 Total long-term borrowings $ 668,173 $ 539,494 Scheduled annual maturities for the long-term borrowings for the years following December 31, 2017 are as follows: (in thousands) 2018 $ 69,684 2019 151,558 2020 105,610 2021 52,189 2022 6,072 Later years 283,060 Total $ 668,173 Federal Home Loan Bank advances Our banking affiliate has available credit with the FHLB of $7.9 billion of which $2.6 billion was utilized as of December 31, 2017 . These advances are secured by loans collateralized by residential mortgages, HELOCs, commercial real estate and FHLB stock and are scheduled to mature in various amounts periodically through the year 2021 . Effective interest rates paid on the long-term advances ranged from 1.11% to 4.19% for the year ended December 31, 2017 and 0.95% to 4.19% for the year ended December 31, 2016 . Subordinated notes Subordinated notes are unsecured and subordinated to our other indebtedness. The subordinated notes mature in various amounts periodically through the year 2027. At December 31, 2017 , all of the subordinated notes are redeemable by the holders prior to maturity at a discount equal to three to 12 months of interest, depending on the term of the note. We may require the holder to give 30 days prior written notice. No sinking fund is required and none has been established to retire the notes. The weighted average interest rate on the subordinated notes are presented in the following table: December 31 2017 2016 2015 Subordinated notes weighted average interest rate 2.85 % 2.71 % 2.73 % Junior subordinated debt The junior subordinated debt is comprised of the debt securities issued by FNB in relation to our six unconsolidated subsidiary trusts (collectively, the Trusts), which are unconsolidated variable interest entities. One hundred percent of the common equity of each Trust is owned by FNB. The Trusts were formed for the purpose of issuing FNB-obligated mandatorily redeemable capital securities, or trust preferred securities (TPS) to third-party investors. The proceeds from the sale of TPS and the issuance of common equity by the Trusts were invested in junior subordinated debt securities issued by FNB, which are the sole assets of each Trust. Since third-party investors are the primary beneficiaries, the Trusts are not consolidated in our financial statements. The Trusts pay dividends on the TPS at the same rate as the distributions paid by us on the junior subordinated debt held by the Trusts. F.N.B. Statutory Trust II was formed by us, and the other five statutory trusts were assumed through acquisitions. The acquired statutory trusts were adjusted to fair value in conjunction with the various acquisitions. During 2016, we redeemed $10.0 million of the TPS issued by Omega Financial Capital Trust I. We record the distributions on the junior subordinated debt issued to the Trusts as interest expense. The TPS are subject to mandatory redemption, in whole or in part, upon repayment of the junior subordinated debt. The TPS are eligible for redemption, at any time, at our discretion. Under capital guidelines, effective January 1, 2016, the junior subordinated debt, net of our investments in the Trusts, is included in tier 2 capital. We have entered into agreements which, when taken collectively, fully and unconditionally guarantee the obligations under the TPS subject to the terms of each of the guarantees. The following table provides information relating to the Trusts as of December 31, 2017 : (dollars in thousands) Trust Preferred Securities Common Securities Junior Subordinated Debt Stated Maturity Date Interest Rate Rate Reset Factor F.N.B. Statutory Trust II $ 21,500 $ 665 $ 22,165 6/15/2036 3.24 % LIBOR + 165 basis points (bps) Omega Financial Capital Trust I 26,000 1,114 26,473 10/18/2034 3.54 % LIBOR + 219 bps Yadkin Valley Statutory Trust I 25,000 774 20,863 12/15/2037 2.91 % LIBOR + 132 bps FNB Financial Services Capital Trust I 25,000 774 21,804 9/30/2035 2.80 % LIBOR + 146 bps American Community Capital Trust II 10,000 310 10,448 12/15/2033 4.14 % LIBOR + 280 bps Crescent Financial Capital Trust I 8,000 248 8,594 10/7/2033 4.46 % LIBOR + 310 bps Total $ 115,500 $ 3,885 $ 110,347 Other subordinated debt Subordinated Debt Due 2025. In an October 2015 debt offering, we issued $100.0 million aggregate principal amount of 4.875% subordinated notes due in October 2025. The net proceeds of the debt offering after deducting underwriting discounts and commissions and offering costs were $98.4 million , and as of December 31, 2017 , the carrying value was $98.8 million . These subordinated notes are eligible for treatment as tier 2 capital for regulatory capital purposes. Subordinated Debt Due 2024. In conjunction with the YDKN acquisition, we assumed $15.5 million aggregate principal amount of 7.25% subordinated notes due in March 2024. These subordinated notes, which are eligible for treatment as tier 2 capital for regulatory capital purposes, were adjusted to fair value at the time of acquisition, and as of December 31, 2017 , the carrying value was $16.8 million . Subordinated Debt Due 2023. In conjunction with the YDKN acquisition, we assumed $38.1 million aggregate principal amount of 7.625% subordinated notes due in August 2023. These subordinated notes, which are eligible for treatment as tier 2 capital for regulatory capital purposes, were adjusted to fair value at the time of acquisition, and as of December 31, 2017 , the carrying value was $44.5 million . Additionally, on May 1, 2017, we repaid $7.5 million in other subordinated debt that we acquired from YDKN.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES We are exposed to certain risks arising from both our business operations and economic conditions. We principally manage our exposures to a wide variety of business and operational risks through management of our core business activities. We manage economic risks, including interest rate risk, primarily by managing the amount, source, and duration of our assets and liabilities, and through the use of derivative instruments. Derivative instruments are used to reduce the effects that changes in interest rates may have on net income and cash flows. We also use derivative instruments to facilitate transactions on behalf of our customers. All derivatives are carried on the consolidated balance sheets at fair value and do not take into account the effects of master netting arrangements we have with other financial institutions. Credit risk is included in the determination of the estimated fair value of derivatives. Derivative assets are reported in the consolidated balance sheets in other assets and derivative liabilities are reported in the consolidated balance sheets in other liabilities. Changes in fair value are recognized in earnings except for certain changes related to derivative instruments designated as part of a cash flow hedging relationship. The following table presents notional amounts and gross fair values of our derivative assets and derivative liabilities which are not offset in the balance sheet. December 31 2017 2016 Notional Amount Fair Value Notional Amount Fair Value (in thousands) Asset Liability Asset Liability Gross Derivatives Subject to master netting arrangements: Interest rate contracts – designated $ 705,000 $ 228 $ 1,982 $ 450,000 $ 9,256 $ 1,171 Interest rate swaps – not designated 2,245,442 1,169 11,599 1,689,157 12,720 34,046 Equity contracts – not designated 1,180 51 — 1,180 61 — Total subject to master netting arrangements 2,951,622 1,448 13,581 2,140,337 22,037 35,217 Not subject to master netting arrangements: Interest rate swaps – not designated 2,245,442 27,233 15,303 1,689,157 32,170 11,866 Interest rate lock commitments – not designated 88,107 1,594 5 — — — Forward delivery commitments – not designated 106,572 233 148 — — — Credit risk contracts – not designated 235,196 39 109 174,538 13 123 Equity contracts – not designated 1,180 — 51 1,180 — 61 Total not subject to master netting arrangements 2,676,497 29,099 15,616 1,864,875 32,183 12,050 Total $ 5,628,119 $ 30,547 $ 29,197 $ 4,005,212 $ 54,220 $ 47,267 On January 3, 2017, the Chicago Mercantile Exchange (CME) enacted a rule change which in effect results in the legal characterization of variation margin payments for certain derivative contracts as settlement of the derivatives mark-to-market exposure and not collateral. This rule change became effective for us in the first quarter of 2017. Accordingly, we have changed our reporting of certain derivatives to record variation margin on trades cleared through CME as settled where we had previously recorded cash collateral. The daily settlement of the derivative exposure does not change or reset the contractual terms of the instrument. Derivatives Designated as Hedging Instruments under GAAP Interest Rate Contracts. We entered into interest rate derivative agreements to modify the interest rate characteristics of certain commercial loans and five of our FHLB advances from variable rate to fixed rate in order to reduce the impact of changes in future cash flows due to market interest rate changes. These agreements are designated as cash flow hedges (i.e., hedging the exposure to variability in expected future cash flows). The effective portion of the derivative’s gain or loss is initially reported as a component of other comprehensive income and subsequently reclassified into earnings in the same line item associated with the forecasted transaction when the forecasted transaction affects earnings. The ineffective portion of the gain or loss is reported in earnings immediately. Following is a summary of key data related to interest rate contracts: December 31 2017 2016 (in thousands) Notional amount $ 705,000 $ 450,000 Fair value included in other assets 228 9,256 Fair value included in other liabilities 1,982 1,171 The following table shows amounts reclassified from accumulated other comprehensive income (AOCI): December 31 2017 2016 (in thousands) Total Net of Tax Total Net of Tax Reclassified from AOCI to interest income $ 1,446 $ 940 $ 2,659 $ 1,728 Reclassified from AOCI to interest expense 1,374 893 703 457 As of December 31, 2017 , the maximum length of time over which forecasted interest cash flows are hedged is six years. In the twelve months that follow December 31, 2017 , we expect to reclassify from the amount currently reported in AOCI net derivative gains of $1.4 million ( $0.9 million net of tax), in association with interest on the hedged loans and FHLB advances. This amount could differ from amounts actually recognized due to changes in interest rates, hedge de-designations, and the addition of other hedges subsequent to December 31, 2017 . There were no components of derivative gains or losses excluded from the assessment of hedge effectiveness related to these cash flow hedges. For the years ended December 31, 2017 and 2016 , there was no hedge ineffectiveness. Also, during the years ended December 31, 2017 and 2016 , there were no gains or losses from cash flow hedge derivatives reclassified to earnings because it became probable that the original forecasted transactions would not occur. Derivatives Not Designated as Hedging Instruments under GAAP Interest Rate Swaps. We enter into interest rate swap agreements to meet the financing, interest rate and equity risk management needs of qualifying commercial loan customers. These agreements provide the customer the ability to convert from variable to fixed interest rates. The credit risk associated with derivatives executed with customers is essentially the same as that involved in extending loans and is subject to normal credit policies and monitoring. Swap derivative transactions with customers are not subject to enforceable master netting arrangements and are generally secured by rights to non-financial collateral, such as real and personal property. We enter into positions with a derivative counterparty in order to offset our exposure on the fixed components of the customer interest rate swap agreements. We seek to minimize counterparty credit risk by entering into transactions only with high-quality financial dealer institutions. These arrangements meet the definition of derivatives, but are not designated as hedging instruments under ASC 815, Derivatives and Hedging. Substantially all contracts with dealers that require central clearing (generally, transactions since June 10, 2014) are novated to a SEC registered clearing agency who becomes our counterparty. Following is a summary of key data related to interest rate swaps: December 31 2017 2016 (in thousands) Notional amount $ 4,490,884 $ 3,378,314 Fair value included in other assets 28,402 44,890 Fair value included in other liabilities 26,902 45,912 The interest rate swap agreement with the loan customer and with the counterparty is reported at fair value in other assets and other liabilities on the consolidated balance sheets with any resulting gain or loss recorded in current period earnings as other income or other expense. Interest Rate Lock Commitments . Interest rate lock commitments (IRLCs) represent an agreement to extend credit to a mortgage loan borrower, or an agreement to purchase a loan from a third-party originator, whereby the interest rate on the loan is set prior to funding. We are bound to fund the loan at a specified rate, regardless of whether interest rates have changed between the commitment date and the loan funding date, subject to the loan approval process. The borrower is not obligated to perform under the commitment. As such, outstanding IRLCs subject us to interest rate risk and related price risk during the period from the commitment to the borrower through the loan funding date, or commitment expiration. The IRLCs generally range between 30 to 90 days. The IRLCs are reported at fair value in other assets and other liabilities on the consolidated balance sheets with any resulting gain or loss recorded in current period earnings as mortgage banking operations income. Forward Delivery Commitments . Forward delivery commitments on mortgage-backed securities are used to manage the interest rate and price risk of our IRLCs and mortgage loan held for sale inventory by fixing the forward sale price that will be realized upon sale of the mortgage loans into the secondary market. Historical commitment-to-closing ratios are considered to estimate the quantity of mortgage loans that will fund within the terms of the IRLCs. The forward delivery contracts are reported at fair value in other assets and other liabilities on the consolidated balance sheets with any resulting gain or loss recorded in current period earnings as mortgage banking operations income. Credit Risk Contracts. We purchase and sell credit protection under risk participation agreements to share with other counterparties some of the credit exposure related to interest rate derivative contracts or to take on credit exposure to generate revenue. We will make/receive payments under these agreements if a customer defaults on our obligation to perform under certain derivative swap contracts. Risk participation agreements sold with notional amounts totaling $154.2 million as of December 31, 2017 have remaining terms ranging from six months to nine years. Under these agreements, our maximum exposure assuming a customer defaults on their obligation to perform under certain derivative swap contracts with third parties would be $108,000 and $123,000 at December 31, 2017 and 2016 . The fair values of risk participation agreements purchased and sold were $39,000 and $(108,000) , respectively, at December 31, 2017 and $13,000 and $(123,000) , respectively at December 31, 2016 . Counterparty Credit Risk We are party to master netting arrangements with most of our swap derivative counterparties. Collateral, usually marketable securities and/or cash, is exchanged between FNB and our counterparties, and is generally subject to thresholds and transfer minimums. For swap transactions that require central clearing, we post cash to our clearing agency. Collateral positions are valued daily, and adjustments to amounts received and pledged by us are made as appropriate to maintain proper collateralization for these transactions. Certain master netting agreements contain provisions that, if violated, could cause the counterparties to request immediate settlement or demand full collateralization under the derivative instrument. If we had breached our agreements with our derivative counterparties we would be required to settle our obligations under the agreements at the termination value and would be required to pay an additional $0.9 million and $1.1 million as of December 31, 2017 and 2016 , respectively, in excess of amounts previously posted as collateral with the respective counterparty. The following table presents a reconciliation of the net amounts of derivative assets and derivative liabilities presented in the balance sheets to the net amounts that would result in the event of offset: Amount Not Offset in the (in thousands) Net Amount Financial Cash Net December 31, 2017 Derivative Assets Interest rate contracts: Designated $ 228 $ 228 $ — $ — Not designated 1,169 1,169 — — Equity contracts – not designated 51 51 — — Total $ 1,448 $ 1,448 $ — $ — Derivative Liabilities Interest rate contracts: Designated $ 1,982 $ 1,982 $ — $ — Not designated 11,599 10,940 — 659 Total $ 13,581 $ 12,922 $ — $ 659 December 31, 2016 Derivative Assets Interest rate contracts: Designated $ 9,256 $ 843 $ 8,413 $ — Not designated 12,720 474 12,132 114 Equity contracts – not designated 61 61 — — Total $ 22,037 $ 1,378 $ 20,545 $ 114 Derivative Liabilities Interest rate contracts: Designated $ 1,171 $ 1,171 $ — $ — Not designated 34,046 15,490 17,651 905 Total $ 35,217 $ 16,661 $ 17,651 $ 905 The following table presents the effect of certain derivative financial instruments on the income statement: Year Ended December 31, (in thousands) Income Statement Location 2017 2016 Interest Rate Contracts Interest income – loans and leases $ 1,446 $ 2,659 Interest Rate Contracts Interest expense – short-term borrowings 1,374 703 Interest Rate Swaps Other income (592 ) (529 ) Credit Risk Contracts Other income 40 16

Commitments, Credit Risk and Co

Commitments, Credit Risk and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments, Credit Risk and Contingencies	COMMITMENTS, CREDIT RISK AND CONTINGENCIES We have commitments to extend credit and standby letters of credit that involve certain elements of credit risk in excess of the amount stated in the consolidated balance sheets. Our exposure to credit loss in the event of non-performance by the customer is represented by the contractual amount of those instruments. The credit risk associated with commitments to extend credit and standby letters of credit is essentially the same as that involved in extending loans and leases to customers and is subject to normal credit policies. Since many of these commitments expire without being drawn upon, the total commitment amounts do not necessarily represent future cash flow requirements. Following is a summary of off-balance sheet credit risk information: December 31 2017 2016 (in thousands) Commitments to extend credit $ 6,957,822 $ 4,486,164 Standby letters of credit 132,904 117,732 At December 31, 2017 , funding of 76.8% of the commitments to extend credit was dependent on the financial condition of the customer. We have the ability to withdraw such commitments at our discretion. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Based on management’s credit evaluation of the customer, collateral may be deemed necessary. Collateral requirements vary and may include accounts receivable, inventory, property, plant and equipment and income-producing commercial properties. Standby letters of credit are conditional commitments issued by us that may require payment at a future date. The credit risk involved in issuing letters of credit is actively monitored through review of the historical performance of our portfolios. In addition to the above commitments, subordinated notes issued by FNB Financial Services, LP, a wholly-owned finance subsidiary, are fully and unconditionally guaranteed by FNB. These subordinated notes are included in the summaries of short-term borrowings and long-term borrowings in Notes 12 and 13. Other Legal Proceedings In the ordinary course of business, we are routinely named as defendants in, or made parties to, pending and potential legal actions. Also, as regulated entities, we are subject to governmental and regulatory examinations, information-gathering requests, and may be subject to investigations and proceedings (both formal and informal). Such threatened claims, litigation, investigations, regulatory and administrative proceedings typically entail matters that are considered incidental to the normal conduct of business. Claims for significant monetary damages may be asserted in many of these types of legal actions, while claims for disgorgement, restitution, penalties and/or other remedial actions or sanctions may be sought in regulatory matters. In these instances, if we determine that we have meritorious defenses, we will engage in an aggressive defense. However, if management determines, in consultation with counsel, that settlement of a matter is in the best interest of our Company and our shareholders, we may do so. It is inherently difficult to predict the eventual outcomes of such matters given their complexity and the particular facts and circumstances at issue in each of these matters. However, on the basis of current knowledge and understanding, and advice of counsel, we do not believe that judgments, sanctions, settlements or orders, if any, that may arise from these matters (either individually or in the aggregate, after giving effect to applicable reserves and insurance coverage) will have a material adverse effect on our financial position or liquidity, although they could have a material effect on net income in a given period. In view of the inherent unpredictability of outcomes in litigation and governmental and regulatory matters, particularly where (i) the damages sought are indeterminate, (ii) the proceedings are in the early stages, or (iii) the matters involve novel legal theories or a large number of parties, as a matter of course, there is considerable uncertainty surrounding the timing or ultimate resolution of litigation and governmental and regulatory matters, including a possible eventual loss, fine, penalty, business or adverse reputational impact, if any, associated with each such matter. In accordance with applicable accounting guidance, we establish accruals for litigation and governmental and regulatory matters when those matters proceed to a stage where they present loss contingencies that are both probable and reasonably estimable. In such cases, there may be a possible exposure to loss in excess of any amounts accrued. We will continue to monitor such matters for developments that could affect the amount of the accrual, and will adjust the accrual amount as appropriate. If the loss contingency in question is not both probable and reasonably estimable, we do not establish an accrual and the matter will continue to be monitored for any developments that would make the loss contingency both probable and reasonably estimable. We believe that our accruals for legal proceedings are appropriate and, in the aggregate, are not material to our consolidated financial position, although future accruals could have a material effect on net income in a given period.

Stock Incentive Plans

Stock Incentive Plans	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Incentive Plans	STOCK INCENTIVE PLANS Restricted Stock We issue restricted stock awards, consisting of both restricted stock and restricted stock units, to key employees under our Incentive Compensation Plan (Plan). We issue time-based awards and performance-based awards under this Plan, both of which are based on a three -year vesting period. The grant date fair value of the time-based awards is equal to the price of our common stock on the grant date. The fair value of the performance-based awards is based on a Monte-Carlo Simulation valuation of our common stock as of the grant date. The assumptions used for this valuation include stock price volatility, risk-free interest rate and dividend yield. We issued 251,379 and 277,174 performance-based restricted stock units in 2017 and 2016 , respectively. For performance-based restricted stock awards granted, the recipients will earn shares, totaling between 0% and 175% of the number of units issued, based on our total stockholder return relative to a specified peer group of financial institutions over the three -year period. These market-based restricted stock units are included in the table below as if the recipients earned shares equal to 100% of the units issued. The following table details our issuance of restricted stock awards and the aggregate weighted average grant date fair values under these plans for the years indicated. As of December 31, 2017 , we had available up to 2,642,020 shares of common stock to issue under this Plan. (dollars in thousands) 2017 2016 2015 Restricted stock awards 713,998 574,125 664,337 Weighted average grant date fair values $ 10,474 $ 7,383 $ 8,802 The unvested restricted stock awards are eligible to receive cash dividends or dividend equivalents which are ultimately used to purchase additional shares of stock and are subject to forfeiture if the requisite service period is not completed or the specified performance criteria are not met. These awards are subject to certain accelerated vesting provisions upon retirement, death, disability or in the event of a change of control as defined in the award agreements. The following table summarizes the activity relating to restricted stock awards during the periods indicated: 2017 2016 2015 Awards Weighted Average Grant Price per Share Awards Weighted Average Grant Price per Share Awards Weighted Average Grant Price per Share Unvested awards outstanding at beginning of year 1,836,363 $ 12.97 1,548,444 $ 12.85 1,354,093 $ 11.86 Granted 713,998 14.67 574,125 12.86 664,337 13.25 Net adjustment due to performance (64,861 ) 13.85 72,070 11.79 13,115 19.74 Vested (542,580 ) 12.71 (384,704 ) 12.11 (484,010 ) 10.70 Forfeited/expired (31,018 ) 14.03 (31,394 ) 13.02 (41,130 ) 13.24 Dividend reinvestment 63,960 13.80 57,822 13.08 42,039 11.86 Unvested awards outstanding at end of year 1,975,862 13.64 1,836,363 12.97 1,548,444 12.85 The following table provides certain information relating to restricted stock awards: Year Ended December 31 2017 2016 2015 (in thousands) Stock-based compensation expense $ 8,201 $ 7,066 $ 4,461 Tax benefit related to stock-based compensation expense 2,870 2,473 1,561 Fair value of awards vested 8,106 4,587 6,070 As of December 31, 2017 , there was $12.1 million of unrecognized compensation cost related to unvested restricted stock awards including $0.7 million that is subject to accelerated vesting under the Plan’s immediate vesting upon retirement provision for awards granted prior to the adoption of ASC 718, Compensation - Stock Compensation . The components of the restricted stock awards as of December 31, 2017 are as follows: (dollars in thousands) Service- Based Awards Performance- Based Awards Total Unvested restricted stock awards 1,062,902 912,960 1,975,862 Unrecognized compensation expense $ 7,037 $ 5,062 $ 12,099 Intrinsic value $ 14,689 $ 12,617 $ 27,306 Weighted average remaining life (in years) 1.93 1.72 1.83 Stock Options All outstanding stock options were assumed from acquisitions and are fully vested. Upon consummation of our acquisitions, all outstanding stock options issued by the acquired companies were converted into equivalent FNB stock options. We issue shares of treasury stock or authorized but unissued shares to satisfy stock options exercised. The following table summarizes the activity relating to stock options during the periods indicated: 2017 Weighted Average Exercise Price per Share 2016 Weighted Average Exercise Price per Share 2015 Weighted Average Exercise Price per Share Options outstanding at beginning of year 892,532 $ 8.95 435,340 $ 8.86 568,834 $ 8.86 Assumed from acquisitions 207,645 8.92 1,707,036 7.83 — — Exercised (255,503 ) 10.21 (1,128,075 ) 7.18 (93,822 ) 5.94 Forfeited/expired (122,024 ) 12.12 (121,769 ) 9.33 (39,672 ) 15.66 Options outstanding and exercisable at end of year 722,650 7.96 892,532 8.95 435,340 8.86 The following table summarizes information about stock options outstanding at December 31, 2017 : Range of Exercise Prices Options Outstanding and Exercisable Weighted Average Remaining Contractual Years Weighted Average Exercise Price $3.45 - $5.18 162,224 3.07 $ 4.87 $5.19 - $7.78 118,707 3.31 6.84 $7.79 - $11.68 432,260 3.80 9.33 $11.69 - $14.53 9,459 0.69 12.48 722,650 The intrinsic value of outstanding and exercisable stock options at December 31, 2017 was $4.4 million . The aggregate intrinsic value represents the amount by which the fair value of underlying stock exceeds the "in-the-money" option exercise price. The following table summarizes certain information relating to stock options exercised: Year Ended December 31 2017 2016 2015 (in thousands) Proceeds from stock options exercised $ 2,340 $ 7,816 $ 557 Tax benefit recognized from stock options exercised 385 1,862 130 Intrinsic value of stock options exercised 1,001 6,577 693 Warrants In conjunction with our participation in the UST’s CPP, we issued to the UST a warrant to purchase up to 1,302,083 shares of our common stock. Pursuant to Section 13(H) of the Warrant to Purchase Common Stock, the number of shares of common stock issuable upon exercise of the warrant was reduced in half to 651,042 shares on June 16, 2009, the date we completed a public offering. The warrant, which expires in 2019, was sold at auction by the UST and has an exercise price of $11.52 per share. In conjunction with the ANNB acquisition on April 6, 2013, the warrant issued by ANNB to the UST under the CPP has been converted into a warrant to purchase up to 342,564 shares of our common stock at an exercise price of $3.57 per share. Subsequent adjustments related to actual dividends paid by us have increased the share amount of these warrants to 402,287 , with a resulting lower exercise price of $3.04 per share as of December 31, 2017 . The warrant, which was recorded at its fair value on April 6, 2013, was sold at auction by the UST and expires in 2019. In conjunction with the YDKN acquisition on March 11, 2017, the warrant issued by YDKN to the UST under the CPP has been converted into a warrant to purchase up to 207,320 shares of our common stock at an exercise price of $9.63 per share. Subsequent adjustments related to actual dividends paid by us have increased the share amount of these warrants to 210,135 , with a resulting lower exercise price of $9.50 per share as of December 31, 2017 . The warrant, which was recorded at its fair value on March 11, 2017, was sold at auction by the UST and expires in 2019.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Retirement Plans	RETIREMENT PLANS We sponsor the Retirement Income Plan (RIP), a qualified noncontributory defined benefit pension plan that covered substantially all salaried employees hired prior to January 1, 2008. The RIP covers employees who satisfied minimum age and length of service requirements. Our funding guideline has been to make annual contributions to the RIP each year, if necessary, such that minimum funding requirements have been met. The RIP was frozen as of December 31, 2010. We also sponsor two supplemental non-qualified retirement plans. The ERISA Excess Retirement Plan provides retirement benefits equal to the difference, if any, between the maximum benefit allowable under the Internal Revenue Code and the amount that would be provided under the RIP, if no limits were applied. The Basic Retirement Plan (BRP) is applicable to certain officers whom the Board of Directors designates. Officers participating in the BRP receive a benefit based on a target benefit percentage based on years of service at retirement and a designated tier as determined by the Board of Directors. When a participant retires, the benefit under the BRP is a monthly benefit equal to the participant's aggregate target benefit percentage multiplied by the participant’s highest average monthly cash compensation, including bonuses, during five consecutive calendar years within the last ten calendar years of employment before 2009. This monthly benefit is reduced by the monthly benefit the participant receives from the Social Security Administration, the RIP, the ERISA Excess Retirement Plan and the annuity equivalent of the automatic contributions paid to participants under the qualified 401(k) defined contribution plan and the ERISA Excess Lost Match Plan. The BRP was frozen as of December 31, 2008. The ERISA Excess Retirement Plan was frozen as of December 31, 2010. The following tables provide information relating to the accumulated benefit obligation, change in benefit obligation, change in plan assets, the plans’ funded status and the amount included in the consolidated balance sheets for the qualified and non-qualified plans described above (collectively, the Plans): December 31 2017 2016 (in thousands) Accumulated benefit obligation $ 181,412 $ 152,586 Projected benefit obligation at beginning of year $ 152,916 $ 151,015 Acquisition 29,613 — Service cost (13 ) (15 ) Interest cost 6,846 6,129 Actuarial loss 9,061 3,723 Benefits paid (9,728 ) (7,936 ) Settlement (7,158 ) — Projected benefit obligation at end of year $ 181,537 $ 152,916 Fair value of plan assets at beginning of year $ 136,958 $ 132,762 Acquisition 24,961 — Actual return on plan assets 17,327 10,787 Corporation contribution 1,345 1,345 Benefits paid (9,728 ) (7,936 ) Settlement (7,158 ) — Fair value of plan assets at end of year $ 163,705 $ 136,958 Funded status of plans $ (17,832 ) $ (15,958 ) The unrecognized actuarial loss, prior service cost and net transition obligation are required to be recognized into earnings over the average remaining participant life due to the freezing of the RIP, which may, on a net basis reduce future earnings. Actuarial assumptions used in the determination of the projected benefit obligation in the Plans are as follows: Assumptions at December 31 2017 2016 Weighted average discount rate 3.53 % 3.96 % Rates of average increase in compensation levels 3.50 3.50 The discount rate assumption at December 31, 2017 and 2016 was determined using a yield-curve based approach. A yield curve was produced for a universe containing the majority of U.S.-issued Aa-graded corporate bonds, all of which were non-callable (or callable with make-whole provisions), and after excluding the 10% of the bonds with the highest and lowest yields. The discount rate was developed as the level equivalent rate that would produce the same present value as that using spot rates aligned with the projected benefit payments. The net periodic pension cost and other comprehensive income for the Plans included the following components: Year Ended December 31 2017 2016 2015 (in thousands) Service cost $ (13 ) $ (15 ) $ (14 ) Interest cost 6,846 6,129 5,897 Expected return on plan assets (11,121 ) (9,413 ) (9,964 ) Transition amount amortization — — — Prior service credit amortization 7 7 7 Actuarial loss amortization 2,461 2,383 2,112 Net periodic pension income (1,820 ) (909 ) (1,962 ) Settlement charge 168 — — Total pension income (1,652 ) (909 ) (1,962 ) Other changes in plan assets and benefit obligations recognized in other comprehensive income: Current year actuarial loss 2,855 2,349 6,914 Amortization of actuarial loss (2,461 ) (2,383 ) (2,112 ) Amortization of prior service credit (7 ) (7 ) (7 ) Amortization of transition asset — — — Total amount recognized in other comprehensive income 387 (41 ) 4,795 Total amount recognized in net periodic benefit cost and other comprehensive income $ (1,265 ) $ (950 ) $ 2,833 The plans have an actuarial measurement date of December 31. Actuarial assumptions used in the determination of the net periodic pension cost in the Plans are as follows: Assumptions for the Year Ended December 31 2017 2016 2015 Weighted average discount rate 3.96 % 4.19 % 3.85 % Rates of increase in compensation levels 3.50 3.50 3.50 Expected long-term rate of return on assets 7.25 7.25 7.25 The expected long-term rate of return on plan assets has been established by considering historical and anticipated expected returns on the asset classes invested in by the pension trust and the allocation strategy currently in place among those classes. The change in plan assets reflects benefits paid from the qualified pension plans of $8.4 million and $6.6 million for 2017 and 2016 , respectively. The employer did not make any contributions to the qualified pension plans during 2017 or 2016 . For the non-qualified pension plans, the change in plan assets reflects benefits paid from and contributions made to the plans in the same amount. This amount represents the actual benefit payments paid from general assets of $1.3 million for 2017 and $1.3 million for 2016 . As of December 31, 2017 and 2016 , the projected benefit obligation, accumulated benefit obligation and fair value of plan assets for the qualified and non-qualified pension plans were as follows: (in thousands) Qualified Pension Plans Non-Qualified Pension Plans December 31 2017 2016 2017 2016 Projected benefit obligation $ 161,632 $ 132,902 $ 19,905 $ 20,014 Accumulated benefit obligation 161,632 132,902 19,780 19,684 Fair value of plan assets 163,705 136,958 — — The impact of changes in the discount rate and expected long-term rate of return on plan assets would have had the following effects on 2017 pension expense: (in thousands) Estimated Effect on Pension Expense 0.5% decrease in the discount rate $ (97 ) 0.5% decrease in the expected long-term rate of return on plan assets 767 The following table provides information regarding estimated future cash flows relating to the Plans at December 31, 2017 (in thousands): Expected employer contributions: 2018 $ 1,424 Expected benefit payments: 2018 9,474 2019 9,957 2020 10,227 2021 10,390 2022 10,501 2023 – 2027 53,902 The qualified pension plan contributions are deposited into a trust and the qualified benefit payments are made from trust assets. For the non-qualified plans, the contributions and the benefit payments are the same and reflect expected benefit amounts, which we pay from general assets. Our subsidiaries participate in a qualified 401(k) defined contribution plan under which employees may contribute a percentage of their salary. Employees are eligible to participate upon their first day of employment. Under this plan, we match 100% of the first six percent that the employee defers. Additionally, we may provide a performance-based company contribution of up to three percent if we exceed annual financial goals. Our contribution expense is presented in the following table: Year Ended December 31 2017 2016 2015 (in thousands) 401(k) contribution expense $ 12,286 $ 9,069 $ 8,055 We also sponsor an ERISA Excess Lost Match Plan for certain officers. This plan provides retirement benefits equal to the difference, if any, between the maximum benefit allowable under the Internal Revenue Code and the amount that would have been provided under the qualified 401(k) defined contribution plan, if no limits were applied. Pension Plan Investment Policy and Strategy Our investment strategy for the RIP is to diversify plan assets between a wide mix of equity and debt securities in an effort to allow the plan the opportunity to meet the plan’s expected long-term rate of return requirements while minimizing short-term volatility. In this regard, the plan has targeted allocations within the equity securities category for domestic large cap, domestic mid cap, domestic small cap, real estate investment trusts, emerging market and international securities. Within the debt securities category, the plan has targeted allocation levels for U.S. Treasury, U.S. agency, domestic investment-grade bonds, high-yield bonds, inflation-protected securities and international bonds. The following table presents asset allocations for our pension plans as of December 31, 2017 and 2016 , and the target allocation for 2018 , by asset category: Target Allocation Percentage of Plan Assets December 31 2018 2017 2016 Asset Category Equity securities 45 - 65 64 % 61 % Debt securities 30 - 50 33 35 Cash equivalents 0 - 10 3 4 At December 31, 2017 and 2016 , equity securities included 575,128 shares of our common stock, representing 4.9% and 6.7% of total plan assets at December 31, 2017 and 2016 , respectively. Dividends received on our common stock held by the Plan were $276,000 for both 2017 and 2016 . The fair values of our pension plan assets by asset category are as follows: (in thousands) Level 1 Level 2 Level 3 Total December 31, 2017 Asset Class Cash $ 5,613 $ — $ — $ 5,613 Equity securities: F.N.B. Corporation 7,948 — — 7,948 Other large-cap U.S. financial services companies 4,269 — — 4,269 Other large-cap U.S. companies 45,583 — — 45,583 International companies 576 — — 576 Other equity 726 — — 726 Mutual fund equity investments: U.S. equity index funds: U.S. large-cap equity index funds 3,489 — — 3,489 U.S. small-cap equity index funds 3,983 — — 3,983 U.S. mid-cap equity index funds 4,836 — — 4,836 Non-U.S. equities growth fund 13,965 — — 13,965 U.S. equity funds: U.S. mid-cap 9,413 — — 9,413 U.S. small-cap 3,165 — — 3,165 Other 5,681 — — 5,681 Fixed income securities: U.S. Treasury bonds — 121 — 121 U.S. government agencies — 37,671 — 37,671 Corporate bonds — 5,532 — 5,532 Fixed income mutual funds: U.S. investment-grade fixed income securities 11,134 — — 11,134 Non-U.S. fixed income securities — — — — Total $ 120,381 $ 43,324 $ — $ 163,705 (in thousands) Level 1 Level 2 Level 3 Total December 31, 2016 Asset Class Cash $ 5,125 $ — $ — $ 5,125 Equity securities: F.N.B. Corporation 9,219 — — 9,219 Other large-cap U.S. financial services companies 2,999 — — 2,999 Other large-cap U.S. companies 36,570 — — 36,570 International companies 718 — — 718 Other equity 596 — — 596 Mutual fund equity investments: U.S. equity index funds: U.S. large-cap equity index funds 559 — — 559 U.S. small-cap equity index funds 3,035 — — 3,035 U.S. mid-cap equity index funds 3,795 — — 3,795 Non-U.S. equities growth fund 9,555 — — 9,555 U.S. equity funds: U.S. mid-cap 7,615 — — 7,615 U.S. small-cap 3,173 — — 3,173 Other 5,928 — — 5,928 Fixed income securities: U.S. government agencies — 36,891 — 36,891 Fixed income mutual funds: U.S. investment-grade fixed income securities 10,766 — — 10,766 Non-U.S. fixed income securities 414 — — 414 Total $ 100,067 $ 36,891 $ — $ 136,958 The classifications for Level 1, Level 2 and Level 3 are discussed in Note 24, “Fair Value Measurements.”

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The TCJA includes several changes to existing U.S. tax laws that impact us, most notably a reduction of the U.S. corporate income tax rate from 35% to 21% , which became effective January 1, 2018. We recognized the initial income tax effects of the TCJA in our 2017 financial statements in accordance with Staff Accounting Bulletin No. 118, which provides SEC staff guidance for the application of ASC 740, Income Taxes, in the reporting period in which the TCJA was signed into law. As such, our financial results reflect the income tax effects of the TCJA for which the accounting under ASC 740 is complete, as well as for provisional amounts for those specific income tax effects under ASC 740 that are incomplete, but a reasonable estimate could be determined. We did not identify any items for which the income tax effects of the TCJA have not been completed and a reasonable estimate could not be determined as of December 31, 2017. As of December 31, 2017 , we recorded provisional charges related to the remeasurement of the deferred tax assets and liabilities due to the reduction in the corporate tax rate. Examples of unavailable or unanalyzed information for which we have provisional estimates include deferred taxes related to depreciation (including lease financing), partnership earnings, and realized built-in losses from a prior acquisition. These estimates are subject to change as additional data is gathered, as interpretations and guidance are received, and as the final analyses are completed. The measurement period ends when we have analyzed the information necessary to finalize our accounting, but cannot extend beyond one year. The effects of changes in tax rates on deferred tax balances are applicable even in situations in which the related income tax effects of such items were originally recognized in other comprehensive income. This results in stranded tax effects for items that were recorded in AOCI rather than in income from continuing operations. In the fourth quarter of 2017, we elected to change our accounting policy to reclassify the income tax effects related to the TCJA of approximately $14.7 million from AOCI to retained earnings. This change in accounting policy results in the appropriate tax rate being recognized in AOCI for debt and equity investments, certain derivative transactions, and pension and other post-retirement benefit plans. Income Tax Expense Federal and state income tax expense consist of the following: Year Ended December 31 2017 2016 2015 (in thousands) Current income taxes: Federal taxes $ 26,336 $ 57,894 $ 69,572 State taxes 1,746 2,329 989 Total current income taxes 28,082 60,223 70,561 Deferred income taxes: Federal taxes 128,204 14,983 63 State taxes 779 291 (631 ) Total deferred income taxes 128,983 15,274 (568 ) Total income taxes $ 157,065 $ 75,497 $ 69,993 The following table provides a reconciliation between the statutory tax rate and the actual effective tax rate: Year Ended December 31 2017 2016 2015 Statutory tax rate 35.0 % 35.0 % 35.0 % State taxes, net of federal benefit 0.5 0.7 0.8 Valuation allowance reversal — — (0.8 ) Tax-exempt interest (3.3 ) (2.9 ) (2.2 ) Cash surrender value on BOLI (1.1 ) (1.5 ) (1.3 ) Tax credits (2.6 ) (0.9 ) (1.1 ) Affordable housing cost amortization, net of tax benefits 0.2 — — Tax Cuts and Jobs Act revaluation of net deferred tax assets 15.2 — — Other items 0.2 0.2 0.1 Actual effective tax rate 44.1 % 30.6 % 30.5 % The effective tax rate for 2017 was 44.1% , as compared to 30.6% in 2016 . The higher rate is largely due to $54.0 million of income tax expense recorded from the revaluation of net deferred tax assets in connection the TCJA, partially offset by increased tax credit activity in 2017 . The effective tax rates for 2016 and 2015 were lower than the statutory tax rate due to tax benefits resulting from tax-exempt income on investments, loans, tax credits and income from bank-owned life insurance (BOLI). Income tax expense related to gains on the sale of securities is presented in the following table: Year Ended December 31 2017 2016 2015 (in thousands) Income tax expense related to gains on sale of securities $ 2,071 $ 249 $ 288 Deferred Income Taxes Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and tax purposes. Deferred tax assets and liabilities are measured based on the enacted tax rates that will apply in the years in which the temporary differences are expected to be recovered or paid. As such, during December 2017, we remeasured our deferred tax assets and liabilities as a result of the passage of the TCJA. The primary impact of this remeasurement was a reduction in deferred tax assets and liabilities in connection with the reduction of the U.S. corporate income tax rate from 35% to 21% . The following table presents the tax effects of significant temporary differences that give rise to federal and state deferred tax assets and liabilities: December 31 2017 2016 (in thousands) Deferred tax assets: Allowance for credit losses $ 38,933 $ 56,090 Discounts on acquired loans 64,341 48,978 Net operating loss/tax credit carryforwards 47,376 17,753 Deferred compensation 8,534 12,236 Securities impairments 1,092 — Pension and other defined benefit plans 6,768 7,713 Net unrealized securities losses 7,238 6,972 Other 7,787 11,264 Total 182,069 161,006 Valuation allowance (26,620 ) (18,945 ) Total deferred tax assets 155,449 142,061 Deferred tax liabilities: Loan costs (7,211 ) (2,222 ) Depreciation (12,263 ) (12,392 ) Prepaid expenses (3,669 ) (682 ) Amortizable intangibles (18,422 ) (18,506 ) Lease financing (10,035 ) (5,538 ) Debt discharge income deferral (474 ) (1,361 ) Originated mortgage servicing rights (6,178 ) (748 ) Net unrealized securities gains — (86 ) Other (1,647 ) (1,253 ) Total deferred tax liabilities (59,899 ) (42,788 ) Net deferred tax assets $ 95,550 $ 99,273 We establish a valuation allowance when it is more likely than not that we will not be able to realize the benefit of the deferred tax assets or when future deductibility is uncertain. Periodically, the valuation allowance is reviewed and adjusted based on management’s assessment of realizable deferred tax assets. As of December 31, 2017 , the valuation allowance primarily relates to unused federal and state net operating loss carryforwards expiring from 2018 to 2037 . We anticipate that neither the state net operating loss carryforwards nor the other net deferred tax assets at certain of our subsidiaries will be utilized and, as such, has recorded a valuation allowance against the deferred tax assets related to these carryforwards. As of December 31, 2017 , we had approximately $65.5 million of federal net operating loss and built-in loss carryforwards, $5.2 million of federal tax credit carryforwards, and $21.5 million of state net operating loss carryforwards to which we succeeded as a result of the YDKN acquisition. The utilization of these tax attributes is subject to annual limitations under Section 382 of the Internal Revenue Code, or a similar state-level statute, which will cause the utilization of these attributes to be deferred over a number of years, not to exceed beyond 2036 . We have determined that we will likely have sufficient taxable income in the years during which these tax attributes are available to be utilized and, consequently, have determined that no valuation allowance against the recorded deferred tax asset is warranted. Unrecognized Tax Benefits A reconciliation of the beginning and ending amount of unrecognized tax benefits (excluding interest and the federal income tax benefit of unrecognized state tax benefits) is as follows: Year Ended December 31 2017 2016 (in thousands) Balance at beginning of year $ 542 $ 455 Additions based on tax positions related to current year 186 163 Additions based on tax positions of prior year — — Reductions for tax positions of prior years (5 ) — Reductions due to expiration of statute of limitations (73 ) (76 ) Balance at end of year $ 650 $ 542 As of December 31, 2017 and 2016 , we have approximately $0.7 million and $0.5 million , respectively, of unrecognized tax benefits, excluding interest and the federal tax benefit of unrecognized state tax benefits. Also, as of December 31, 2017 and 2016 , additional unrecognized tax benefits relating to accrued interest, net of the related federal tax benefit, amounted to $25,000 and $19,000 , respectively. As of December 31, 2017 , $0.5 million of these tax benefits would affect the effective tax rate if recognized. We recognize potential accrued interest and penalties related to unrecognized tax benefits in income tax expense. To the extent interest is not assessed with respect to uncertain tax positions, amounts accrued will be reduced and reflected as a reduction of the overall income tax provision. We file numerous income tax returns in the U.S. federal jurisdiction and in several state jurisdictions. We are no longer subject to U.S. federal income tax examinations for years prior to 2014 . With limited exception, we are no longer subject to state income tax examinations for years prior to 2014 . We anticipate that a reduction in the unrecognized tax benefit of up to $81 thousand may occur in the next twelve months from the expiration of statutes of limitations which would result in a reduction in income taxes.

Other Comprehensive Income

Other Comprehensive Income	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Other Comprehensive Income	OTHER COMPREHENSIVE INCOME The following table presents changes in AOCI, net of tax, by component: (in thousands) Unrealized Net Gains (Losses) on Securities Available for Sale Unrealized Net Gains (Losses) on Derivative Instruments Unrecognized Pension and Postretirement Obligations Total Year Ended December 31, 2017 Balance at beginning of period $ (18,222 ) $ 5,254 $ (48,401 ) $ (61,369 ) Other comprehensive income (loss) before reclassifications (5,744 ) (759 ) (7 ) (6,510 ) Amounts reclassified from AOCI (411 ) (46 ) — (457 ) Amounts reclassified from AOCI due to tax reform (5,249 ) 958 (10,425 ) (14,716 ) Net current period other comprehensive income (loss) (11,404 ) 153 (10,432 ) (21,683 ) Balance at end of period $ (29,626 ) $ 5,407 $ (58,833 ) $ (83,052 ) The amounts reclassified from AOCI related to securities available for sale are included in net securities gains on the consolidated income statements, while the amounts reclassified from AOCI related to derivative instruments are included in interest income on loans and leases on the consolidated income statements. The tax (benefit) expense amounts reclassified from AOCI in connection with the securities available for sale and derivative instruments reclassifications are included in income taxes on the consolidated statements of income.

Earnings per Common Share

Earnings per Common Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Earnings per Common Share	EARNINGS PER COMMON SHARE The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31 2017 2016 2015 (dollars in thousands, except per share data) Net income $ 199,204 $ 170,891 $ 159,649 Less: Preferred stock dividends 8,041 8,041 8,041 Net income available to common stockholders $ 191,163 $ 162,850 $ 151,608 Basic weighted average common shares outstanding 302,195,295 206,244,498 174,971,785 Net effect of dilutive stock options, warrants and restricted stock 1,662,681 1,524,111 1,367,168 Diluted weighted average common shares outstanding 303,857,976 207,768,609 176,338,953 Earnings per common share: Basic $ 0.63 $ 0.79 $ 0.87 Diluted $ 0.63 $ 0.78 $ 0.86 The following table shows the average shares excluded from the above calculation as their effect would have been anti-dilutive: Year Ended December 31 2017 2016 2015 Average shares excluded from the diluted earnings per common share calculation 910 9,980 18,167

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Regulatory Matters	REGULATORY MATTERS FNB and FNBPA are subject to various regulatory capital requirements administered by the federal banking agencies. Quantitative measures established by regulators to ensure capital adequacy require FNB and FNBPA to maintain minimum amounts and ratios of total, tier 1 and common equity tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined) and of leverage ratio (as defined). Failure to meet minimum capital requirements could lead to initiation of certain mandatory, and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on our consolidated financial statements, dividends and future merger and acquisition activity. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, FNB and FNBPA must meet specific capital guidelines that involve quantitative measures of assets, liabilities and certain off-balance sheet items as calculated under regulatory accounting practices. FNB’s and FNBPA’s capital amounts and classifications are also subject to qualitative judgments by the regulators about components, risk weightings and other factors. As of December 31, 2017 , the most recent notification from the federal banking agencies categorized FNB and FNBPA as “well-capitalized” under the regulatory framework for prompt corrective action. There are no conditions or events since the notification which management believes have changed this categorization. Following are the capital ratios for FNB and FNBPA: Actual Well-Capitalized Requirements Minimum Capital Requirements (dollars in thousands) Amount Ratio Amount Ratio Amount Ratio As of December 31, 2017 F.N.B. Corporation: Total capital $ 2,666,272 11.4 % $ 2,340,362 10.0 % $ 2,164,835 9.3 % Tier 1 capital 2,184,571 9.3 1,872,290 8.0 1,696,763 7.3 Common equity tier 1 2,077,689 8.9 1,521,235 6.5 1,345,708 5.8 Leverage 2,184,571 7.6 1,440,797 5.0 1,152,638 4.0 Risk-weighted assets 23,403,622 FNBPA: Total capital 2,504,191 10.7 2,332,593 10.0 2,157,649 9.3 Tier 1 capital 2,332,892 10.0 1,866,075 8.0 1,691,130 7.3 Common equity tier 1 2,252,892 9.7 1,516,186 6.5 1,341,241 5.8 Leverage 2,332,892 8.1 1,432,604 5.0 1,146,084 4.0 Risk-weighted assets 23,325,934 As of December 31, 2016 F.N.B. Corporation: Total capital $ 1,917,386 12.0 % $ 1,597,951 10.0 % $ 1,378,232 8.6 % Tier 1 capital 1,582,251 9.9 1,278,360 8.0 1,058,642 6.6 Common equity tier 1 1,475,369 9.2 1,038,668 6.5 818,950 5.1 Leverage 1,582,251 7.7 1,027,831 5.0 822,265 4.0 Risk-weighted assets 15,979,505 FNBPA: Total capital 1,768,561 11.1 1,588,989 10.0 1,370,503 8.6 Tier 1 capital 1,614,167 10.2 1,271,191 8.0 1,052,705 6.6 Common equity tier 1 1,534,167 9.7 1,032,843 6.5 814,357 5.1 Leverage 1,614,167 7.9 1,019,034 5.0 815,227 4.0 Risk-weighted assets 15,889,893 In accordance with Basel III standards, the implementation of capital requirements is transitional and phases-in from January 1, 2015 through January 1, 2019. The minimum capital requirements for each period above are based on the requirements that were in effect at that time. Our management believes that FNB and FNBPA will continue to meet all "well-capitalized" requirements after Basel III is completely phased-in. FNBPA was required to maintain aggregate cash reserves with the FRB amounting to $39.6 million at December 31, 2017 . We also maintain deposits for various services such as check clearing. Certain limitations exist under applicable law and regulations by regulatory agencies regarding dividend distributions to a parent by our subsidiaries. As of December 31, 2017 , our subsidiaries had $206.8 million of retained earnings available for distribution to us without prior regulatory approval. Under current FRB regulations, FNBPA is limited in the amount it may lend to non-bank affiliates, including FNB. Such loans must be secured by specified collateral. In addition, any such loans to a non-bank affiliate may not exceed 10% of FNBPA’s capital and surplus and the aggregate of loans to all such affiliates may not exceed 20% of FNBPA’s capital and surplus. The maximum amount that may be borrowed by FNB affiliates under these provisions was $474.8 million at December 31, 2017 .

Cash Flow Information

Cash Flow Information	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash Flow Information	CASH FLOW INFORMATION Following is a summary of supplemental cash flow information: Year Ended December 31 2017 2016 2015 (in thousands) Interest paid on deposits and other borrowings $ 129,024 $ 67,296 $ 47,805 Income taxes paid 52,500 60,000 61,500 Transfers of loans to other real estate owned 34,841 14,592 9,628 Financing of other real estate owned sold 19 441 372 Supplemental non-cash information relating to our acquisitions is included in Note 3, “Mergers and Acquisitions.”

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Business Segments	BUSINESS SEGMENTS We operate in four reportable segments: Community Banking, Wealth Management, Insurance and Consumer Finance. • The Community Banking segment provides commercial and consumer banking services. Commercial banking solutions include corporate banking, small business banking, investment real estate financing, business credit, capital markets and lease financing. Consumer banking products and services include deposit products, mortgage lending, consumer lending and a complete suite of mobile and online banking services. • The Wealth Management segment provides a broad range of personal and corporate fiduciary services including the administration of decedent and trust estates. In addition, it offers various alternative products, including securities brokerage and investment advisory services, mutual funds and annuities. • The Insurance segment includes a full-service insurance agency offering all lines of commercial and personal insurance through major carriers. The Insurance segment also includes a reinsurer. • The Consumer Finance segment primarily makes installment loans to individuals and purchases installment sales finance contracts from retail merchants. The Consumer Finance segment activity is funded through the sale of subordinated notes, which are issued by a wholly-owned subsidiary and guaranteed by us. The following tables provide financial information for these segments of FNB. The information provided under the caption “Parent and Other” represents operations not considered to be reportable segments and/or general operating expenses of FNB, and includes the parent company, other non-bank subsidiaries and eliminations and adjustments to reconcile to the consolidated financial statements. (in thousands) Community Banking Wealth Manage- ment Insurance Consumer Finance Parent and Other Consolidated At or for the Year Ended December 31, 2017 Interest income $ 943,661 $ — $ 81 $ 40,187 $ (3,603 ) $ 980,326 Interest expense 117,951 — — 3,676 12,265 133,892 Net interest income 825,710 — 81 36,511 (15,868 ) 846,434 Provision for credit losses 52,780 — — 8,293 — 61,073 Non-interest income 197,517 39,256 15,671 3,256 (3,251 ) 252,449 Non-interest expense (1) 596,813 30,563 14,507 21,502 639 664,024 Amortization of intangibles 17,050 254 213 — — 17,517 Income tax expense (benefit) 152,778 2,679 (256 ) 5,283 (3,419 ) 157,065 Net income (loss) 203,806 5,760 1,288 4,689 (16,339 ) 199,204 Total assets 31,155,973 24,218 21,062 181,260 35,122 31,417,635 Total intangibles 2,317,151 10,176 12,127 1,809 — 2,341,263 At or for the Year Ended Interest income $ 640,895 $ — $ 84 $ 40,922 $ (2,938 ) $ 678,963 Interest expense 56,182 — — 3,759 7,510 67,451 Net interest income 584,713 — 84 37,163 (10,448 ) 611,512 Provision for credit losses 49,046 — — 6,706 — 55,752 Non-interest income 149,408 35,283 14,750 3,002 (682 ) 201,761 Non-interest expense (1) 437,031 27,201 12,965 21,662 1,064 499,923 Amortization of intangibles 10,526 259 425 — — 11,210 Income tax expense (benefit) 72,619 2,845 532 4,488 (4,987 ) 75,497 Net income (loss) 164,899 4,978 912 7,309 (7,207 ) 170,891 Total assets 21,629,374 19,619 22,053 193,349 (19,578 ) 21,844,817 Total intangibles 1,061,597 10,189 12,340 1,809 — 1,085,935 At or for the Year Ended Interest income $ 509,585 $ — $ 89 $ 39,868 $ (2,747 ) $ 546,795 Interest expense 41,227 — — 3,518 3,828 48,573 Net interest income 468,358 — 89 36,350 (6,575 ) 498,222 Provision for credit losses 33,045 — — 7,396 — 40,441 Non-interest income 114,377 35,246 13,052 2,926 (3,191 ) 162,410 Non-interest expense (1) 320,912 27,264 13,891 20,189 (12 ) 382,244 Amortization of intangibles 7,544 273 488 — — 8,305 Income tax expense (benefit) 66,979 2,803 (412 ) 4,709 (4,086 ) 69,993 Net income (loss) 154,255 4,906 (826 ) 6,982 (5,668 ) 159,649 Total assets 17,349,459 20,753 22,207 195,048 (29,805 ) 17,557,662 Total intangibles 844,630 10,447 12,923 1,809 — 869,809 (1) Excludes amortization of intangibles, which is presented separately.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS We use fair value measurements to record fair value adjustments to certain financial assets and liabilities and to determine fair value disclosures. Securities available for sale and derivatives are recorded at fair value on a recurring basis. Additionally, from time to time, we may be required to record at fair value other assets on a non-recurring basis, such as mortgage loans held for sale, certain impaired loans, OREO and certain other assets. Fair value is defined as an exit price, representing the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurements are not adjusted for transaction costs. Fair value is a market-based measure considered from the perspective of a market participant who holds the asset or owes the liability rather than an entity-specific measure. In determining fair value, we use various valuation approaches, including market, income and cost approaches. ASC 820, Fair Value Measurements and Disclosures , establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability, which are developed based on market data obtained from sources independent of FNB. Unobservable inputs reflect our assumptions about the assumptions that market participants would use in pricing an asset or liability, which are developed based on the best information available in the circumstances. The fair value hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The fair value hierarchy is broken down into three levels based on the reliability of inputs as follows: Measurement Category Definition Level 1 valuation is based upon unadjusted quoted market prices for identical instruments traded in active markets. Level 2 valuation is based upon quoted market prices for similar instruments traded in active markets, quoted market prices for identical or similar instruments traded in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by market data. Level 3 valuation is derived from other valuation methodologies including discounted cash flow models and similar techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in determining fair value. A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Following is a description of the valuation methodologies we use for financial instruments recorded at fair value on either a recurring or non-recurring basis: Securities Available For Sale Securities available for sale consist of both debt and equity securities. These securities are recorded at fair value on a recurring basis. At December 31, 2017 , 100.0% of these securities used valuation methodologies involving market-based or market-derived information, collectively Level 1 and Level 2 measurements, to measure fair value. We closely monitor market conditions involving assets that have become less actively traded. If the fair value measurement is based upon recent observable market activity of such assets or comparable assets (other than forced or distressed transactions) that occur in sufficient volume, and do not require significant adjustment using unobservable inputs, those assets are classified as Level 1 or Level 2; if not, they are classified as Level 3. Making this assessment requires significant judgment. We use prices from independent pricing services and, to a lesser extent, indicative (non-binding) quotes from independent brokers, to measure the fair value of investment securities. We validate prices received from pricing services or brokers using a variety of methods, including, but not limited to, comparison to secondary pricing services, corroboration of pricing by reference to other independent market data such as secondary broker quotes and relevant benchmark indices, and review of pricing information by corporate personnel familiar with market liquidity and other market-related conditions. Derivative Financial Instruments We determine 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. We incorporate credit valuation adjustments to appropriately reflect both our own non-performance risk and the respective counterparty’s non-performance risk in the fair value measurements. In adjusting the fair value of our derivative contracts for the effect of non-performance risk, we consider the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts and guarantees. Although we have determined that the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives and IRLCs utilize Level 3 inputs. Credit valuation estimates of current credit spreads are used to evaluate the likelihood of our default and the default of our counterparties. However, as of December 31, 2017 and 2016 , we have assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our non-IRLC derivative positions and have determined that the credit valuation adjustments are not significant to the overall valuation of our derivatives. As a result, we have determined that our derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The fair value of IRLCs is based upon the estimated fair value of the underlying mortgage loan, including the expected cash flows related to the MSRs and the estimated percentage of IRLCs that will result in a closed mortgage loan, and classified as Level 3. Loans Held For Sale Beginning in 2017, residential mortgage loans held for sale are carried at fair value under the FVO. Prior to 2017, residential mortgage loans held for sale were carried at the lower of cost or fair value accounting, under which, periodically, it may have been necessary to record non-recurring fair value adjustments. Fair value for residential mortgage loans held for sale, when recorded, is based on independent quoted market prices and is classified as Level 2. SBA loans held for sale are carried under lower of cost or fair value accounting, for which, periodically, it may be necessary to record non-recurring fair value adjustments. Fair value for SBA loans held for sale, when recorded, is based on independent quoted market prices and is classified as Level 2. Impaired Loans We reserve for commercial loan relationships greater than or equal to $500,000 that we consider impaired as defined in ASC 310 at the time we identify the loan as impaired based upon the present value of expected future cash flows available to pay the loan, or based upon the fair value of the collateral less estimated selling costs where a loan is collateral dependent. Collateral may be real estate and/or business assets including equipment, inventory and accounts receivable. We determine the fair value of real estate based on appraisals by licensed or certified appraisers. The value of business assets is generally based on amounts reported on the business’ financial statements. Management must rely on the financial statements prepared and certified by the borrower or their accountants in determining the value of these business assets on an ongoing basis, which may be subject to significant change over time. Based on the quality of information or statements provided, management may require the use of business asset appraisals and site-inspections to better value these assets. We may discount appraised and reported values based on management’s historical knowledge, changes in market conditions from the time of valuation or management’s knowledge of the borrower and the borrower’s business. Since not all valuation inputs are observable, we classify these non-recurring fair value determinations as Level 2 or Level 3 based on the lowest level of input that is significant to the fair value measurement. We review and evaluate impaired loans no less frequently than quarterly for additional impairment based on the same factors identified above. Other Real Estate Owned OREO is comprised principally of commercial and residential real estate properties obtained in partial or total satisfaction of loan obligations. OREO acquired in settlement of indebtedness is recorded at the lower of carrying amount of the loan or fair value less costs to sell. Subsequently, these assets are carried at the lower of carrying value or fair value less costs to sell. Accordingly, it may be necessary to record non-recurring fair value adjustments. Fair value is generally based upon appraisals by licensed or certified appraisers and other market information and is classified as Level 2 or Level 3. The following table presents the balances of assets and liabilities measured at fair value on a recurring basis: (in thousands) Level 1 Level 2 Level 3 Total December 31, 2017 Assets Measured at Fair Value Debt securities available for sale U.S. Treasury $ — $ — $ — $ — U.S. government-sponsored entities — 343,942 — 343,942 Residential mortgage-backed securities Agency mortgage-backed securities — 1,598,874 — 1,598,874 Agency collateralized mortgage obligations — 794,957 — 794,957 Non-agency collateralized mortgage obligations — 1 — 1 Commercial mortgage-backed securities — — — — States of the U.S. and political subdivisions — 21,093 — 21,093 Other debt securities — 4,670 — 4,670 Total debt securities available for sale — 2,763,537 — 2,763,537 Equity securities available for sale Fixed income mutual fund 161 — — 161 Financial services industry — 864 — 864 Insurance services industry — — — — Total equity securities available for sale 161 864 — 1,025 Total securities available for sale 161 2,764,401 — 2,764,562 Loans held for sale — 56,458 — 56,458 Derivative financial instruments Trading — 28,453 — 28,453 Not for trading — 500 1,594 2,094 Total derivative financial instruments — 28,953 1,594 30,547 Total assets measured at fair value on a recurring basis $ 161 $ 2,849,812 $ 1,594 $ 2,851,567 Liabilities Measured at Fair Value Derivative financial instruments Trading $ — $ 26,953 $ — $ 26,953 Not for trading — 2,239 5 2,244 Total derivative financial instruments — 29,192 5 29,197 Total liabilities measured at fair value on a recurring basis $ — $ 29,192 $ 5 $ 29,197 (in thousands) Level 1 Level 2 Level 3 Total December 31, 2016 Assets Measured at Fair Value Debt securities available for sale U.S. Treasury $ — $ 29,953 $ — $ 29,953 U.S. government-sponsored entities — 365,098 — 365,098 Residential mortgage-backed securities Agency mortgage-backed securities — 1,252,798 — 1,252,798 Agency collateralized mortgage obligations — 535,974 — 535,974 Non-agency collateralized mortgage obligations — 3 894 897 Commercial mortgage-backed securities — 1,291 — 1,291 States of the U.S. and political subdivisions — 35,849 — 35,849 Other debt securities — 9,487 — 9,487 Total debt securities available for sale — 2,230,453 894 2,231,347 Equity securities available for sale Financial services industry — — 492 492 Insurance services industry 148 — — 148 Total equity securities available for sale 148 — 492 640 Total securities available for sale 148 2,230,453 1,386 2,231,987 Derivative financial instruments Trading — 44,951 — 44,951 Not for trading — 9,269 — 9,269 Total derivative financial instruments — 54,220 — 54,220 Total assets measured at fair value on a recurring basis $ 148 $ 2,284,673 $ 1,386 $ 2,286,207 Liabilities Measured at Fair Value Derivative financial instruments Trading $ — $ 45,973 $ — $ 45,973 Not for trading — 1,294 — 1,294 Total derivative financial instruments — 47,267 — 47,267 Total liabilities measured at fair value on a recurring basis $ — $ 47,267 $ — $ 47,267 The following table presents additional information about assets measured at fair value on a recurring basis and for which we have utilized Level 3 inputs to determine fair value: (in thousands) Other Equity Securities Residential Non-Agency Collateralized Mortgage Obligations Interest Total Year Ended December 31, 2017 Balance at beginning of period $ — $ 492 $ 894 $ — $ 1,386 Total gains (losses) – realized/unrealized: Included in earnings — — 4 — 4 Included in other comprehensive income — 86 (6 ) — 80 Accretion included in earnings (1 ) — 1 — — Purchases, issuances, sales and settlements: Purchases 12,048 — — 1,594 13,642 Issuances — — — — — Sales/redemptions (12,047 ) — (874 ) — (12,921 ) Settlements — — (19 ) (4,569 ) (4,588 ) Transfers from Level 3 — (578 ) — — (578 ) Transfers into Level 3 — — — 4,569 4,569 Balance at end of period $ — $ — $ — $ 1,594 $ 1,594 Year Ended December 31, 2016 Balance at beginning of period $ — $ 439 $ 1,184 $ — $ 1,623 Total gains (losses) – realized/unrealized: Included in earnings — — — — — Included in other comprehensive income — 53 (7 ) — 46 Accretion included in earnings — — 6 — 6 Purchases, issuances, sales and settlements: Purchases — — — — — Issuances — — — — — Sales/redemptions — — — — — Settlements — — (289 ) — (289 ) Transfers from Level 3 — — — — — Transfers into Level 3 — — — — — Balance at end of period $ — $ 492 $ 894 $ — $ 1,386 We review fair value hierarchy classifications on a quarterly basis. Changes in the observability of the valuation attributes may result in reclassification of certain financial assets or liabilities. Such reclassifications are reported as transfers in/out of Level 3 at fair value at the beginning of the period in which the changes occur. See the “Securities Available for Sale” discussion within this footnote for information relating to determining Level 3 fair values. During 2017 , we acquired $12.0 million in other debt securities from YDKN that are measured at Level 3. These securities were sold during the second quarter of 2017. During 2017 , we transferred equity securities totaling $0.6 million from Level 3 to Level 2, as a result of increased trading activity relating to these securities. There were no transfers of assets or liabilities between the hierarchy levels during 2016 . For the years ended December 31, 2017 and 2016 , there were no gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held as of those dates. The total gains (losses) included in earnings are in the net securities gains (losses) line item in the consolidated statements of income. In accordance with GAAP, from time to time, we measure certain assets at fair value on a non-recurring basis. These adjustments to fair value usually result from the application of the lower of cost or fair value accounting or write-downs of individual assets. Valuation methodologies used to measure these fair value adjustments were previously described. For assets measured at fair value on a non-recurring basis still held at the balance sheet date, the following table provides the hierarchy level and the fair value of the related assets or portfolios: (in thousands) Level 1 Level 2 Level 3 Total December 31, 2017 Impaired loans $ — $ 2,813 $ 1,297 $ 4,110 Other real estate owned — 10,513 10,823 21,336 Loans held for sale - SBA — — 36,432 36,432 Other assets - SBA servicing asset — — 5,058 5,058 December 31, 2016 Impaired loans $ — $ 500 $ 5,883 $ 6,383 Other real estate owned — 11,017 3,181 14,198 Substantially all of the fair value amounts in the table above were estimated at a date during the twelve months ended December 31, 2017 and 2016 . Consequently, the fair value information presented is not as of the period’s end. Impaired loans measured or re-measured at fair value on a non-recurring basis during 2017 had a carrying amount of $7.3 million and an allocated allowance for credit losses of $3.6 million . The allocated allowance is based on fair value of $4.1 million less estimated costs to sell of $0.4 million . The allowance for credit losses includes a provision applicable to the current period fair value measurements of $3.7 million , which was included in the provision for credit losses for 2017 . OREO with a carrying amount of $23.3 million was written down to $18.7 million (fair value of $21.3 million less estimated costs to sell of $2.6 million ), resulting in a loss of $4.6 million , which was included in earnings for 2017 . Fair Value of Financial Instruments The following methods and assumptions were used to estimate the fair value of each financial instrument: Cash and Cash Equivalents, Accrued Interest Receivable and Accrued Interest Payable. For these short-term instruments, the carrying amount is a reasonable estimate of fair value. Securities. For both securities available for sale and securities held to maturity, fair value equals the quoted market price from an active market, if available, and is classified within Level 1. If a quoted market price is not available, fair value is estimated using quoted market prices for similar securities or pricing models, and is classified as Level 2. Where there is limited market activity or significant valuation inputs are unobservable, securities are classified within Level 3. Under current market conditions, assumptions used to determine the fair value of Level 3 securities have greater subjectivity due to the lack of observable market transactions. Loans and Leases. The fair value of fixed rate loans and leases is estimated by discounting the future cash flows using the current rates at which similar loans and leases would be made to borrowers with similar credit ratings and for the same remaining maturities less an illiquidity discount. The fair value of variable and adjustable rate loans and leases approximates the carrying amount. Due to the significant judgment involved in evaluating credit quality, loans and leases are classified within Level 3 of the fair value hierarchy. Loan Servicing Rights . For both MSRs and SBA-servicing rights, both classified as Level 3 assets, fair value is determined using a discounted cash flow valuation method. These models use significant unobservable inputs including discount rates, prepayment rates and cost to service which have greater subjectivity due to the lack of observable market transactions. Derivative Assets and Liabilities. See the “Derivative Financial Instruments” discussion included within this footnote . Deposits. The estimated fair value of demand deposits, savings accounts and certain money market deposits is the amount payable on demand at the reporting date because of the customers’ ability to withdraw funds immediately. The fair value of fixed-maturity deposits is estimated by discounting future cash flows using rates currently offered for deposits of similar remaining maturities. Short-Term Borrowings. The carrying amounts for short-term borrowings approximate fair value for amounts that mature in 90 days or less. The fair value of subordinated notes is estimated by discounting future cash flows using rates currently offered. Long-Term Borrowings. The fair value of long-term borrowings is estimated by discounting future cash flows based on the market prices for the same or similar issues or on the current rates offered to us for debt of the same remaining maturities. Loan Commitments and Standby Letters of Credit. Estimates of the fair value of these off-balance sheet items were not made because of the short-term nature of these arrangements and the credit standing of the counterparties. Also, unfunded loan commitments relate principally to variable rate commercial loans, typically are non-binding, and fees are not normally assessed on these balances. Nature of Estimates . Many of the estimates presented herein are based upon the use of highly subjective information and assumptions and, accordingly, the results may not be precise. Management believes that fair value estimates may not be comparable to other financial institutions due to the wide range of permitted valuation techniques and numerous estimates which must be made. Further, because the disclosed fair value amounts were estimated as of the balance sheet date, the amounts actually realized or paid upon maturity or settlement of the various financial instruments could be significantly different. The fair values of our financial instruments are as follows: Fair Value Measurements (in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 December 31, 2017 Financial Assets Cash and cash equivalents $ 479,443 $ 479,443 $ 479,443 $ — $ — Securities available for sale 2,764,562 2,764,562 161 2,764,401 — Securities held to maturity 3,242,268 3,218,379 — 3,218,379 — Net loans and leases, including loans held for sale 20,916,277 20,661,196 — 56,458 20,604,738 Loan servicing rights 34,111 37,758 — — 37,758 Derivative assets 30,547 30,547 — 28,953 1,594 Accrued interest receivable 94,254 94,254 94,254 — — Financial Liabilities Deposits 22,399,725 22,359,182 17,779,246 4,579,936 — Short-term borrowings 3,678,337 3,678,723 3,678,723 — — Long-term borrowings 668,173 675,489 — — 675,489 Derivative liabilities 29,197 29,197 — 29,192 5 Accrued interest payable 12,480 12,480 12,480 — — December 31, 2016 Financial Assets Cash and cash equivalents $ 371,407 $ 371,407 $ 371,407 $ — $ — Securities available for sale 2,231,987 2,231,987 148 2,230,453 1,386 Securities held to maturity 2,337,342 2,294,777 — 2,293,091 1,686 Net loans and leases, including loans held for sale 14,750,792 14,464,274 — — 14,464,274 Loan servicing rights 13,521 17,546 — — 17,546 Derivative assets 54,220 54,220 — 54,220 — Accrued interest receivable 58,712 58,712 58,712 — — Financial Liabilities Deposits 16,065,647 16,045,323 13,489,152 2,556,171 — Short-term borrowings 2,503,010 2,503,277 2,503,277 — — Long-term borrowings 539,494 536,088 — — 536,088 Derivative liabilities 47,267 47,267 — 47,267 — Accrued interest payable 7,612 7,612 7,612 — —

Parent Company Financial Statem

Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Financial Statements	PARENT COMPANY FINANCIAL STATEMENTS The following is condensed financial information of F.N.B. Corporation (parent company only). In this information, the parent company’s investments in subsidiaries are stated at cost plus equity in undistributed earnings of subsidiaries since acquisition. This information should be read in conjunction with the consolidated financial statements. Balance Sheets (in thousands) December 31 2017 2016 Assets Cash and cash equivalents $ 165,698 $ 164,276 Securities available for sale 864 492 Other assets 22,344 17,405 Investment in bank subsidiary 4,553,703 2,598,520 Investments in and advances to non-bank subsidiaries 294,236 269,998 Total Assets $ 5,036,845 $ 3,050,691 Liabilities Other liabilities $ 33,000 $ 26,063 Advances from affiliates 306,096 295,897 Long-term borrowings 279,536 147,916 Subordinated notes: Short-term 7,993 8,172 Long-term 1,026 1,026 Total Liabilities 627,651 479,074 Stockholders’ Equity 4,409,194 2,571,617 Total Liabilities and Stockholders’ Equity $ 5,036,845 $ 3,050,691 Statements of Income (in thousands) Year Ended December 31 2017 2016 2015 Income Dividend income from subsidiaries: Bank $ 149,000 $ 108,954 $ 87,580 Non-bank 9,210 8,525 7,863 158,210 117,479 95,443 Interest income 5,323 5,041 4,845 Other income 100 2,799 1,053 Total Income 163,633 125,319 101,341 Expenses Interest expense 17,977 13,609 9,526 Other expenses 10,320 10,377 8,993 Total Expenses 28,297 23,986 18,519 Income Before Taxes and Equity in Undistributed Income of Subsidiaries 135,336 101,333 82,822 Income tax benefit 2,737 6,352 5,088 138,073 107,685 87,910 Equity in undistributed income (loss) of subsidiaries: Bank 60,567 60,924 71,581 Non-bank 564 2,282 158 Net Income $ 199,204 $ 170,891 $ 159,649 Statements of Cash Flows (in thousands) Year Ended December 31 2017 2016 2015 Operating Activities Net income $ 199,204 $ 170,891 $ 159,649 Adjustments to reconcile net income to net cash flows from operating activities: Undistributed earnings from subsidiaries (61,131 ) (63,206 ) (71,739 ) Other, net 5,441 (2,530 ) 680 Net cash flows provided by operating activities 143,514 105,155 88,590 Investing Activities Proceeds from sale of securities available for sale — 815 — Net (increase) decrease in advances to subsidiaries (9,838 ) (6,263 ) 3,285 Payment for further investment in subsidiaries (4,841 ) (71,050 ) (9,060 ) Net cash received in business combinations 3,173 1,089 — Net cash flows (used in) provided by investing activities (11,506 ) (75,409 ) (5,775 ) Financing Activities Net decrease in advance from affiliate 10,018 6,356 (2,797 ) Net decrease in short-term borrowings (179 ) (44 ) (135 ) Decrease in long-term debt (1,510 ) (10,291 ) (650 ) Increase in long-term debt 563 381 98,794 Net proceeds from issuance of common stock 11,181 18,472 12,731 Tax benefit of stock-based compensation — 1,813 28 Cash dividends paid: Preferred stock (8,041 ) (8,041 ) (8,041 ) Common stock (142,618 ) (101,670 ) (84,511 ) Net cash flows (used in) provided by financing activities (130,586 ) (93,024 ) 15,419 Net (Decrease) Increase in Cash and Cash Equivalents 1,422 (63,278 ) 98,234 Cash and cash equivalents at beginning of year 164,276 227,554 129,320 Cash and Cash Equivalents at End of Year $ 165,698 $ 164,276 $ 227,554 Cash paid during the year for: Interest $ 15,807 $ 13,620 $ 8,309

Quarterly Earnings Summary (Una

Quarterly Earnings Summary (Unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Earnings Summary (Unaudited) [Abstract]
Quarterly Earnings Summary (Unaudited)	QUARTERLY EARNINGS SUMMARY (UNAUDITED) Dollars in thousands, except per share data Quarter Ended 2017 Dec. 31 Sept. 30 June 30 Mar. 31 Total interest income $ 271,085 $ 263,514 $ 251,034 $ 194,693 Total interest expense 41,049 38,283 32,619 21,941 Net interest income 230,036 225,231 218,415 172,752 Provision for credit losses 16,699 16,768 16,756 10,850 Net securities gains 21 2,777 493 2,625 Other non-interest income 65,083 63,374 65,585 52,491 Total non-interest expense 166,529 163,743 163,714 187,555 Net income 24,126 77,693 74,406 22,979 Net income available to common stockholders 22,115 75,683 72,396 20,969 Per Common Share Basic earnings per share $ 0.07 $ 0.23 $ 0.22 $ 0.09 Diluted earnings per share 0.07 0.23 0.22 0.09 Cash dividends declared 0.12 0.12 0.12 0.12 Quarter Ended 2016 Dec. 31 Sept. 30 June 30 Mar. 31 Total interest income $ 177,168 $ 175,110 $ 170,931 $ 155,754 Total interest expense 17,885 17,604 16,562 15,400 Net interest income 159,283 157,506 154,369 140,354 Provision for credit losses 12,705 14,639 16,640 11,768 Net securities gains 116 299 226 71 Other non-interest income 50,950 52,941 51,185 45,973 Total non-interest expense 123,806 121,050 129,629 136,648 Net income 51,291 52,168 41,300 26,132 Net income available to common stockholders 49,280 50,158 39,290 24,122 Per Common Share Basic earnings per share $ 0.23 $ 0.24 $ 0.19 $ 0.12 Diluted earnings per share 0.23 0.24 0.19 0.12 Cash dividends declared 0.12 0.12 0.12 0.12

Summary of Significant Accoun37

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation Our accompanying consolidated financial statements and these notes to the financial statements include subsidiaries in which we have a controlling financial interest. We own and operate FNBPA, First National Trust Company, First National Investment Services Company, LLC, F.N.B. Investment Advisors, Inc., First National Insurance Agency, LLC (FNIA), Regency, Bank Capital Services, LLC, and F.N.B. Capital Corporation, LLC, and include results for each of these entities in the accompanying consolidated financial statements. The accompanying consolidated financial statements include all adjustments that are necessary, in the opinion of management, to fairly reflect our financial position and results of operations in accordance with U.S. generally accepted accounting principles (GAAP). All significant intercompany balances and transactions have been eliminated. Certain prior period amounts have been reclassified to conform to the current period presentation. Such reclassifications had no impact on our net income and stockholders’ equity. Events occurring subsequent to the date of the December 31, 2017 balance sheet have been evaluated for potential recognition or disclosure in the consolidated financial statements through the date of the filing of the consolidated financial statements with the Securities and Exchange Commission (SEC).
Use of Estimates	Use of Estimates Our accounting and reporting policies conform with GAAP. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could materially differ from those estimates. Material estimates that are particularly susceptible to significant changes include the allowance for credit losses, accounting for acquired loans, fair value of financial instruments, goodwill and other intangible assets, litigation and income taxes and deferred tax assets.
Business Combinations	Business Combinations Business combinations are accounted for by applying the acquisition method . Under the acquisition method, identifiable assets acquired and liabilities assumed, and any non-controlling interest in the acquiree at the acquisition date are measured at their fair values as of that date, and are recognized separately from goodwill. Results of operations of the acquired entities are included in the consolidated statements of income from the date of acquisition.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash on hand, cash items in transit and amounts due from the Federal Reserve Bank (FRB) and other depository institutions (including interest-bearing deposits).
Securities	Securities Investment securities, which consist of debt securities and certain equity securities, comprise a significant portion of our consolidated balance sheets. Such securities can be classified as trading, held to maturity or available for sale. As of December 31, 2017 and 2016 , we did not hold any trading securities. Securities held to maturity are comprised of debt securities, for which management has the positive intent and ability to hold until their maturity. Such securities are carried at cost, adjusted for related amortization of premiums and accretion of discounts through interest income from securities, and subject to evaluation for other-than-temporary impairment (OTTI). Securities that are not classified as trading or held to maturity are classified as available for sale. Our available for sale securities portfolio is comprised of debt securities and marketable equity securities. Such securities are carried at fair value with net unrealized gains and losses deemed to be temporary and OTTI attributable to non-credit factors reported separately as a component of other comprehensive income, net of tax. We evaluate our securities in a loss position for OTTI on a quarterly basis at the individual security level based on our intent to sell. If we intend to sell the debt security or it is more likely than not we will be required to sell the security before recovery of its amortized cost basis, OTTI must be recognized in earnings equal to the entire difference between the investments’ amortized cost basis and its fair value. If we do not intend to sell the debt security and it is not more likely than not that we will be required to sell the security before recovery of its amortized cost basis, OTTI must be separated into the amount representing credit loss and the amount related to all other market factors. The amount related to credit loss will be recognized in earnings. The amount related to other market factors will be recognized in other comprehensive income, net of applicable taxes. We perform our OTTI evaluation process in a consistent and systematic manner and include an evaluation of all available evidence. This process considers factors such as length of time and anticipated recovery period of the impairment, recent events specific to the issuer and recent experience regarding principal and interest payments.
Securities Sold Under Agreements to Repurchase	Securities Sold Under Agreements to Repurchase Securities sold under agreements to repurchase are accounted for as collateralized financing transactions and are recorded at the amounts at which the securities were sold plus accrued interest. Securities, generally U.S. government and federal agency securities, pledged as collateral under these financing arrangements cannot be sold or repledged by the secured party. The fair value of collateral either received from or provided to a third party is continually monitored and additional collateral is obtained or is requested to be returned to us as deemed appropriate.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities From time to time, we may enter into derivative transactions principally to protect against the risk of adverse price or interest rate movements on the value of certain assets and liabilities and on future cash flows. All derivative instruments are carried at fair value on the balance sheet as either an asset or liability. Accounting for the changes in fair value of a derivative is dependent upon whether or not it has been designated in a formal, qualifying hedging relationship. For derivatives in qualifying hedging relationships, we formally document all relationships between hedging instruments and hedged items, as well as our risk management objective and strategy for undertaking each hedge transaction. Changes in fair value of a derivative instrument that has been designated and qualifies as a cash flow hedge are recorded in accumulated other comprehensive income (AOCI), net of tax. Amounts are reclassified from AOCI to the consolidated statements of income in the period or periods in which the hedged transaction affects earnings. At the hedge’s inception and at least quarterly thereafter, a formal assessment is performed to determine whether changes in the fair values or cash flows of the derivative instruments have been highly effective in offsetting changes in fair values or cash flows of the hedged items and whether they are expected to be highly effective in the future. If it is determined a derivative instrument has not been or will not continue to be highly effective as a hedge, hedge accounting is discontinued. Derivative gains and losses under cash flow hedges not effective in hedging the change in fair value or expected cash flows of the hedged item are recognized immediately in the consolidated statements of income. In addition, we enter into interest rate swap agreements to meet the financing, interest rate and equity risk management needs of qualifying commercial loan customers. These agreements provide the customer the ability to convert from variable to fixed interest rates. We then enter into positions with a derivative counterparty in order to offset our exposure on the fixed components of the customer agreements. The credit risk associated with derivatives executed with customers is essentially the same as that involved in extending loans and is subject to normal credit policies and monitoring. We seek to minimize counterparty credit risk by entering into transactions with only high-quality institutions. These arrangements meet the definition of derivatives, but are not designated as qualifying hedging relationships. The interest rate swap agreement with the loan customer and with the counterparty are reported at fair value in other assets and other liabilities on the consolidated balance sheets with any resulting gain or loss recorded in current period earnings as other income.
Loans Held for Sale and Loan Commitments	Loans Held for Sale and Loan Commitments Certain of our residential mortgage loans are originated or purchased for sale in the secondary mortgage loan market. Effective January 1, 2017, we made an automatic election to account for all future originated or purchased residential mortgage loans held for sale under the fair value option (FVO). The FVO election is intended to better reflect the underlying economics and better facilitate the economic hedging of the loans. The FVO is applied on an instrument by instrument basis and is an irrevocable election. Additionally, with the election of the FVO, fees and costs associated with the origination and acquisition of residential mortgage loans held for sale are expensed as incurred, rather than deferred. Changes in fair value under the FVO are recorded in mortgage banking operations non-interest income on the consolidated statements of income. Fair value is determined on the basis of rates obtained in the respective secondary market for the type of loan held for sale. Prior to the FVO election, loans were generally sold at a premium or discount from the carrying amount of the loan which represented the lower of cost or fair value. Gain or loss on the sale of loans is recorded in mortgage banking operations non-interest income. Interest income on loans held for sale is recorded in interest income. We routinely issue interest rate lock commitments for residential mortgage loans that we intend to sell. These interest rate lock commitments are considered derivatives. We also enter into loan sale commitments to sell these loans when funded to mitigate the risk that the market value of residential mortgage loans may decline between the time the rate commitment is issued to the customer and the time we sell the loan. These loan sale commitments are also derivatives. Both types of derivatives are recorded at fair value on the consolidated balance sheets with changes in fair value recorded in mortgage banking operations non-interest income. We also originate loans guaranteed by the Small Business Administration (SBA) for the purchase of businesses, business startups, business expansion, equipment, and working capital. All SBA loans are underwritten and documented as prescribed by the SBA. Starting in the first quarter of 2017, the guaranteed portion of SBA loans originated with the intention to sell on the secondary market are classified as held for sale and are carried at the lower of cost or fair value. At the time of the sale, we allocate the carrying value of the entire loan between the guaranteed portion sold and the unguaranteed portion retained based on their relative fair value which results in a discount recorded on the retained portion of the loan. The guaranteed portion is typically sold at a premium and the gain is recognized in other income for any net premium received in excess of the relative fair value of the portion of the loan transferred. The net carrying value of the retained portion of the loans is included in the appropriate loan classification for disclosure purposes, primarily commercial real estate or commercial and industrial.
Loans (Excluding Acquired Loans)	Loans (Excluding Acquired Loans) Loans we intend to hold for the foreseeable future or until maturity or payoff are reported at their outstanding principal balances, net of any deferred origination fees or costs. Interest income on loans is computed over the term of the loans using the effective interest method. Loan origination fees and certain direct costs incurred to extend credit are deferred and amortized over the term of the loan or loan commitment period as an adjustment to the related loan yield.
Non-performing Loans/ Deteriorated Credit Quality	Non-performing Loans Interest is not accrued on loans where collectability is uncertain. We discontinue interest accruals on loans generally when principal or interest is due and has remained unpaid for a certain number of days unless the loan is both well secured and in the process of collection. Commercial loans are placed on non-accrual at 90 days, installment loans are placed on non-accrual at 120 days and residential mortgages and consumer lines of credit are generally placed on non-accrual at 180 days. Past due status is based on the contractual terms of the loan. When a loan is placed on non-accrual status, all unpaid interest is reversed against interest income and the amortization of deferred fees and costs is suspended. Payments subsequently received are generally applied to either principal or interest or both, depending on management’s evaluation of collectability. A loan is returned to accrual status when principal and interest are no longer past due and collectability is probable. This generally requires a sustained period of timely principal and interest payments. Loans are generally written off when deemed uncollectible or when they reach a predetermined number of days past due depending upon loan product, terms, and other factors. Recoveries of amounts previously charged off are credited to the allowance for credit losses. We consider a loan impaired when, based on current information and events, it is probable that we will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered in determining impairment include payment status, collateral value and the probability of collecting scheduled principal and interest payments when due. The impairment loss is measured by either the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s obtainable market price, or the fair value of the collateral, less estimated selling costs, if the loan is collateral dependent. Acquired impaired loans are not classified as non-performing assets as the loans are considered to be performing. Restructured loans are those in which concessions of terms have been made as a result of deterioration in a borrower’s financial condition. In general, the modification or restructuring of a debt constitutes a troubled debt restructuring (TDR) if we for economic or legal reasons related to the borrower’s financial difficulties grant a concession to the borrower that we would not otherwise consider under current market conditions. Debt restructurings or loan modifications for a borrower occur in the normal course of business and do not necessarily constitute TDRs. To designate a loan as a TDR, the presence of both borrower financial distress and a concession of terms must exist. Additionally, a loan designated as a TDR does not necessarily result in the automatic placement of the loan on non-accrual status. When the full collection of principal and interest is reasonably assured on a loan designated as a TDR and the borrower does not otherwise meet the criteria for non-accrual status, we will continue to accrue interest on the loan. A restructured acquired loan that is accounted for as a component of a pool in accordance is not considered a TDR.
Allowance for Credit Losses	Allowance for Credit Losses The allowance for credit losses is established as losses are estimated to have occurred through a provision charged to earnings. Loan losses are charged against the allowance for credit losses when management believes the uncollectability of a loan balance is confirmed. Subsequent recoveries, if any, are credited to the allowance for credit losses. Allowances for impaired commercial loans over $500,000 are generally determined based on collateral values or the present value of estimated cash flows. All other impaired loans are evaluated in the aggregate based on loan segment loss given default. Changes in the allowance for credit losses related to impaired loans are charged or credited to the provision for credit losses. The allowance for credit losses is maintained at a level that, in management’s judgment, is believed appropriate to absorb probable losses associated with specifically identified loans, as well as estimated probable credit losses inherent in the remainder of the loan portfolio. The appropriateness of the allowance for credit losses is based on management’s evaluation of potential loan losses in the loan portfolio, which includes an assessment of past experience, current economic conditions in specific industries and geographic areas, general economic conditions, known and inherent risks in the loan portfolio, the estimated value of underlying collateral and residuals and changes in the composition of the loan portfolio. Determination of the allowance for credit losses is inherently subjective as it requires significant estimates, including the amounts and timing of expected future cash flows on impaired loans, estimated losses on pools of homogeneous loans based on transition matrices with predefined loss emergence periods and consideration of qualitative factors, all of which are susceptible to significant change.
Acquired Loans	Acquired Loans Acquired loans (impaired and non-impaired) are initially recorded at their acquisition-date fair values. Fair values are based on a discounted cash flow methodology that involves assumptions and judgments as to credit risk, default rates, loss severity, collateral values, discount rates, payment speeds, prepayment risk, and liquidity risk. The carryover of allowance for credit losses related to acquired loans is prohibited as any credit losses in the loans are included in the determination of the fair value of the loans at the acquisition date. The allowance for credit losses on acquired loans reflects only those losses incurred after acquisition and represents the present value of cash flows expected at acquisition that is no longer expected to be collected. At acquisition, we consider the following factors as indicators that an acquired loan has evidence of deterioration in credit quality and is therefore impaired and in the scope of ASC 310-30: • loans that were 90 days or more past due; • loans that had an internal risk rating of substandard or worse. Substandard is consistent with regulatory definitions and is defined as having a well-defined weakness that jeopardizes liquidation of the loan; • loans that were classified as non-accrual by the acquired bank at the time of acquisition; or • loans that had been previously modified in a TDR. Any acquired loans that were not individually in the scope of ASC 310-30 because they didn’t meet the criteria above were pooled into groups of similar loans based on various factors including borrower type, loan purpose, and collateral type. For these pools, we used certain loan information, including outstanding principal balance, estimated expected losses, weighted average maturity, weighted average margin, and weighted average interest rate along with estimated prepayment rates, probability of default and loss given default to estimate the expected cash flow for each loan pool. We believe analogizing to ASC 310-30 is the more appropriate option to follow in accounting for discount accretion on non-impaired acquired loans other than revolving loans and therefore account for such loans in accordance with ASC 310-30. ASC 310-30 guidance does not apply to revolving loans. Consequently, discount accretion on revolving loans acquired is accounted for using the ASC 310-20 approach. The excess of cash flows expected to be collected at acquisition over recorded fair value is referred to as the accretable yield. The accretable yield is recognized into income over the remaining life of the loan, or pool of loans, using an effective yield method, if the timing and/or amount of cash flows expected to be collected can be reasonably estimated (the accretion model). If the timing and/or amount of cash flows expected to be collected cannot be reasonably estimated, the cost recovery method of income recognition must be used. The difference between the loan’s total scheduled principal and interest payments over all cash flows expected at acquisition is referred to as the non-accretable difference. The non-accretable difference represents contractually required principal and interest payments which we do not expect to collect. Over the life of the acquired loan, we continue to estimate cash flows expected to be collected. Decreases in expected cash flows, other than from prepayments or rate adjustments, are recognized as impairments through a charge to the provision for credit losses resulting in an increase in the allowance for credit losses. Subsequent improvements in cash flows result in first, reversal of existing valuation allowances recognized subsequent to acquisition, if any, and next, an increase in the amount of accretable yield to be subsequently recognized on a prospective basis over the loan’s remaining life. Acquired loans that met the criteria for non-accrual of interest prior to acquisition are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of expected cash flows on such loans. Accordingly, we do not consider acquired contractually delinquent loans to be non-accrual or non-performing and continue to recognize interest income on these loans using the accretion model.
Premises and Equipment	Premises and Equipment Premises and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the asset’s estimated useful life. Leasehold improvements are expensed over the lesser of the asset’s estimated useful life or the term of the lease including renewal periods when reasonably assured. Useful lives are dependent upon the nature and condition of the asset and range from 3 to 40 years. Maintenance and repairs are charged to expense as incurred, while major improvements are capitalized and amortized to expense over the identified useful life. Premises and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying value may not be recoverable.
Cloud Computing Arrangements	Cloud Computing Arrangements Beginning in 2016, for new or materially modified contracts, we prospectively adopted new accounting principles to evaluate fees paid for cloud computing arrangements to determine if those arrangements include the purchase of or license to use software that should be accounted for separately as internal-use software. If a contract includes the purchase or license to use software that should be accounted for separately as internal-use software, the contract is amortized over the software’s identified useful life in amortization of intangibles. For contracts that do not include a software license, the contract is accounted for as a service contract with fees paid recorded in other non-interest expense.
Other Real Estate Owned	Other Real Estate Owned Other real estate owned (OREO) is comprised principally of commercial and residential real estate properties obtained in partial or total satisfaction of loan obligations. OREO acquired in settlement of indebtedness is included in other assets initially at the lower of estimated fair value of the asset less estimated selling costs or the carrying amount of the loan. Changes to the value subsequent to transfer are recorded in non-interest expense along with direct operating expenses. Gains or losses not previously recognized resulting from sales of OREO are recognized in non-interest expense on the date of sale.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess of the cost of an acquisition over the fair value of the net assets acquired. Other intangible assets represent purchased assets that lack physical substance but can be distinguished from goodwill because of contractual or other legal rights. Intangible assets that have finite lives, such as core deposit intangibles, customer relationship intangibles and renewal lists, are amortized over their estimated useful lives and subject to periodic impairment testing. Core deposit intangibles are primarily amortized over ten years using accelerated methods. Customer renewal lists are amortized over their estimated useful lives which range from eight to thirteen years . Goodwill and other intangibles are subject to impairment testing at the reporting unit level, which must be conducted at least annually. We perform impairment testing during the fourth quarter of each year, or more frequently if impairment indicators exist. We also continue to monitor other intangibles for impairment and to evaluate carrying amounts, as necessary. Determining the fair value of a reporting unit under the goodwill impairment test is judgmental and often involves the use of significant estimates and assumptions. Similarly, estimates and assumptions are used in determining the fair value of other intangible assets. Estimates of fair value are primarily determined using discounted cash flows, market comparisons and recent transactions. These approaches use significant estimates and assumptions including projected future cash flows, discount rates reflecting the market rate of return, projected growth rates and determination and evaluation of appropriate market comparables. However, future events could cause us to conclude that goodwill or other intangibles have become impaired, which would result in recording an impairment loss. Any resulting impairment loss could have a material adverse impact on our financial condition and results of operations.
Loan Servicing Rights	Loan Servicing Rights We have two primary classes of servicing rights, residential mortgage loan servicing and SBA-guaranteed loan servicing. We recognize the right to service residential mortgage loans and SBA-guaranteed loans for others as an asset whether we purchase the servicing rights or as a result from a sale of loans that we originate when the servicing is contractually separated from the underlying loan and retained by us. We initially record servicing rights at fair value in other assets, net on the consolidated balance sheet. Subsequently, servicing rights are measured at the lower of cost or fair value. Servicing rights are amortized in proportion to, and over the period of, estimated net servicing income in mortgage banking operations income for residential mortgage loans and non-interest income for SBA-guaranteed loans. The amount and timing of estimated future net cash flows are updated based on actual results and updated projections. Mortgage servicing rights (MSRs) are separated into pools based on common risk characteristics of the underlying loans and evaluated for impairment at least quarterly. SBA-guaranteed servicing rights are evaluated for impairment at least quarterly on an aggregate basis. Impairment, if any, is recognized when carrying value exceeds the fair value as determined by calculating the present value of expected net future cash flows. If impairment exists at the pool level for residential mortgage loans or on an aggregate basis for SBA-guaranteed loans, the servicing right is written down through a valuation allowance and is charged against mortgage banking operations income or non-interest income, respectively.
Bank-Owned Life Insurance (BOLI)	Bank-Owned Life Insurance (BOLI) We have purchased life insurance policies on certain current and former directors, officers and employees for which the Corporation is the owner and beneficiary. These policies are recorded in the consolidated balance sheet at their cash surrender value, or the amount that could be realized by surrendering the policies. Tax-exempt income from death benefits and changes in the net cash surrender value are recorded in bank owned life insurance income.
Low Income Housing Tax Credit Partnerships	Low Income Housing Tax Credit Partnerships We invest in various affordable housing projects that qualify for low income housing tax credits (LIHTCs). The net investments are recorded in other assets on the consolidated balance sheets. These investments generate a return through the realization of federal tax credits. We use the proportional amortization method to account for a majority of our investments in these entities. LIHTCs that do not meet the requirements of the proportional amortization method are recognized using the equity method.
Income Taxes	Income Taxes We file a consolidated federal income tax return. The provision for federal and state income taxes is based on income reported on the consolidated financial statements, rather than the amounts reported on the respective income tax returns. Deferred tax assets and liabilities are computed using tax rates expected to apply to taxable income in the years in which those assets and liabilities are expected to be realized. The effect on deferred tax assets and liabilities resulting from a change in tax rates is recognized as income or expense in the period that the change in tax rates is enacted. Beginning in the fourth quarter of 2017, we made an accounting policy election to reclassify the stranded tax effects that relate to a change in the federal tax rate from AOCI to retained earnings in accordance with newly adopted accounting guidance. We believe this change in accounting policy reduces the cost and complexity of accounting for stranded tax effects due to a change in federal tax rates. We make certain estimates and judgments in determining income tax expense for financial statement purposes. These estimates and judgments are applied in the calculation of certain tax credits and in the calculation of the deferred income tax expense or benefit associated with certain deferred tax assets and liabilities. Significant changes to these estimates may result in an increase or decrease to our tax provision in a subsequent period. We recognize interest and/or penalties related to income tax matters in income tax expense. We assess the likelihood that we will be able to recover our deferred tax assets. If recovery is not likely, we will increase our provision for income taxes by recording a valuation allowance against the deferred tax assets that are unlikely to be recovered. We believe that we will ultimately recover the deferred tax assets recorded on our balance sheet. However, should there be a change in our ability to recover our deferred tax assets, the effect of this change would be recorded through the provision for income taxes in the period during which such change occurs. We periodically review the tax positions we take on our tax return and apply a more likely than not recognition threshold for all tax positions that are uncertain. The amount recognized in the financial statements is the largest amount of tax benefit that is greater than 50% likely of being realized on examination. For tax positions not meeting the more likely than not test, no tax benefit is recorded.
Marketing Costs	Marketing Costs Marketing costs are generally expensed as incurred.
Per Share Amounts	Per Share Amounts Earnings per common share is computed using net income available to common stockholders, which is net income adjusted for preferred stock dividends. Basic earnings per common share is calculated by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding, net of unvested shares of restricted stock. Diluted earnings per common share is calculated by dividing net income available to common stockholders by the weighted average number of shares of common stock outstanding, adjusted for the dilutive effect of potential common shares issuable for stock options, warrants and restricted shares, as calculated using the treasury stock method. Adjustments to net income available to common stockholders and the weighted average number of shares of common stock outstanding are made only when such adjustments dilute earnings per common share. Beginning in 2017, the assumed proceeds from applying the treasury stock method when computing diluted earnings per share excludes the amount of excess tax benefits that would have been recognized in accumulated paid-in capital in accordance with newly adopted accounting guidance.
Retirement Plans	Retirement Plans FNB sponsors retirement plans for our employees. The calculation of the obligations and related expenses under these plans requires use of actuarial valuation methods and assumptions. The plans utilize assumptions and methods including reflecting trust assets at their fair value for the qualified pension plans and recognizing the overfunded and underfunded status of the plans on our consolidated balance sheets. Gains and losses, prior service costs and credits are recognized in AOCI, net of tax, until they are amortized, or immediately upon curtailment.
Stock Based Compensation	Stock-Based Compensation Our stock based compensation awards requires the measurement and recognition of compensation expense, based on estimated fair values, for all stock-based awards, including stock options and restricted stock, made to employees and directors. We are required to estimate the fair value of stock-based awards on the date of grant. The value of the award is recognized as expense in our consolidated statements of comprehensive income over the shorter of requisite service periods or the period through the date that the employee first becomes eligible to retire. Some of our plans contain performance targets that affect vesting and can be achieved after the requisite service period and are accounted for as performance conditions. Performance targets are not reflected in the estimation of the award’s grant date fair value. Compensation cost for awards with non-market based performance targets is recognized in the period in which it becomes probable that the performance condition will be achieved. Compensation cost for awards with market based performance targets is recognized based on the award’s grant date fair value. Prior to 2017, because stock-based compensation expense was based on awards that are ultimately expected to vest, stock-based compensation expense was reduced to account for estimated forfeitures. Beginning in 2017, we elected to change our accounting policy to account for forfeitures as they occur. The estimate for forfeitures prior to this election was immaterial to our consolidated financial statements. We believe this change in accounting policy reduces the cost and complexity of accounting for stock-based compensation and is preferable to estimating forfeitures at the time of grant.
New Accounting Standards	The following paragraphs summarize accounting pronouncements issued by the Financial Accounting Standards Board (FASB) that we recently adopted or will be adopting in the future. Reporting Comprehensive Income Accounting Standards Update (ASU or Update) 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , allows for the reclassification from other comprehensive income to retained earnings for stranded tax effects resulting from the enacted tax bill H.R.1, commonly referred to as the Tax Cuts and Jobs Act (the TCJA). The Update also allows an accounting policy election to reclassify other stranded tax effects that relate to the TCJA but not directly related to the change in federal tax rate. This Update is effective in the first quarter of 2019. Early adoption is permitted for reporting periods for which financial statements have not yet been issued. We adopted this Update in the fourth quarter of 2017 by retrospective application. Upon adoption, the Corporation made a policy election to reclassify stranded tax effects of approximately $14.7 million from AOCI to retained earnings using the specific identification method. Stock-Based Compensation ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting , provides guidance about which changes to the terms and conditions of a share-based payment award requires the application of modification accounting. The Update is effective in the first quarter of 2018. Early adoption is permitted. This Update was adopted in the third quarter of 2017 by prospective application to awards modified on or after the adoption date. This Update did not have a material effect on our consolidated financial statements. ASU 2016-09, Compensation—Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The Update was adopted in the first quarter of 2017 by an application method determined by the type of transaction impacted by the adoption. This Update did not have a material effect on our consolidated financial statements. Securities ASU 2017-08, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities which shortens the amortization period for the premium on certain purchased callable securities to the earliest call date. The accounting for purchased callable debt securities held at a discount does not change. The Update is effective in the first quarter of 2019. Early adoption is permitted. The Update is to be applied using a modified retrospective transition method and is not expected to have a material effect on our consolidated financial statements. Retirement Benefits ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, requires that an employer disaggregate the service cost component from the other components of net benefit cost. The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allows only the service cost component of net benefit cost to be eligible for capitalization. The Update is effective the first quarter of 2018. Early adoption is permitted. The Update is to be applied using a retrospective transition method to adopt the requirement for separate presentation in the income statement of service costs and other components and a prospective transition method to adopt the requirement to limit the capitalization of benefit costs to the service cost component. This Update is not expected to have a material effect on our consolidated financial statements. Goodwill ASU 2017-04, Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment , eliminates the requirement of Step 2 in the current guidance to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, entities will record an impairment charge based on the excess of a reporting unit’s carrying amount over its fair value in Step 1 of the current guidance. The Update is effective the first quarter of 2020. Early adoption is permitted for annual or interim goodwill impairment tests with a measurement date after January 1, 2017. We adopted this Update in the first quarter of 2017 and it did not have a material effect on our consolidated financial statements. Business Combinations ASU 2017-01, Business Combinations (Topic 850): Clarifying the Definition of a Business , clarifies the definition of a business with the objective of providing guidance to assist in the evaluation of whether transactions should be accounted for as acquisitions (disposals) of assets or businesses. The Update is effective for the first quarter of 2018. Early adoption is permitted for transactions that occurred before the issuance date or effective date of the Update if the transactions were not reported in financial statements that have been issued or made available for issuance. We adopted this Update in the first quarter of 2017. This Update is applied prospectively and did not have a material effect on our consolidated financial statements. Statement of Cash Flows ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force), adds or clarifies guidance on eight cash flow issues. The Update is effective the first quarter of 2018. This Update will be applied retrospectively to all periods presented. Early adoption is permitted. This Update is not expected to have a material effect on our consolidated financial statements. Credit Losses ASU 2016-13 , Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , replaces the current incurred loss impairment methodology with a methodology that reflects current expected credit losses (commonly referred to as “CECL”) for most financial assets measured at amortized cost and certain other instruments, including loans, held-to-maturity debt securities, net investments in leases and off-balance sheet credit exposures. CECL requires loss estimates for the remaining life of the financial asset at the time the asset is originated or acquired, considering historical experience, current conditions and reasonable and supportable forecasts. In addition, the Update will require the use of a modified available-for-sale debt security impairment model and eliminate the current accounting for purchased credit impaired loans and debt securities. The Update is effective the first quarter of 2020 under a cumulative-effect adjustment to retained earnings. Early adoption is permitted for fiscal years beginning after December 15, 2018. The CECL model is a significant change from existing GAAP and may result in a material change to the Corporation’s accounting for financial instruments. We are reviewing our business processes, information systems and controls to support recognition and disclosures under this Update. This review includes an assessment of our existing credit models and the financial statement disclosure requirements. The impact of this Update will be dependent on the portfolio composition, credit quality and economic conditions at the time of adoption. Revenue Recognition ASU 2014-09, Revenue from Contracts with Customers (Topic 606), modifies the guidance used to recognize revenue from contracts with customers for transfers of goods and services and transfers of nonfinancial assets, unless those contracts are within the scope of other guidance. The guidance also requires new qualitative and quantitative disclosures about contract balances and performance obligations. We will adopt ASU 2014-09 in the first quarter of 2018 under the modified retrospective method where the cumulative effect is recognized at the date of initial application. Based on our evaluation under the current guidance, we estimate that substantially all of our interest income and non-interest income will not be impacted by the adoption of this ASU because either the revenue from those contracts with customers is covered by other guidance in U.S. GAAP or the revenue recognition outcomes anticipated with the adoption of this ASU will likely be similar to our current revenue recognition practices. In addition, we reviewed, and where necessary, enhanced our business processes, systems and controls to support recognition and disclosures under the new standard. The adoption of this Update is not expected to have a material effect on our consolidated financial statements. Investments ASU 2016-07, Investments—Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting, eliminates the requirement for an investor to retrospectively apply the equity method when an investment that it had accounted for by another method qualifies for use of the equity method. The Update was adopted in the first quarter of 2017 by prospective application. This Update did not have a material effect on our consolidated financial statements. Derivative and Hedging Activities ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities , improves the financial reporting of hedging to better align with the entity’s risk management activities. In addition, this Update makes certain targeted improvements to simplify the application of the current hedge accounting guidance. The Update is effective in the first quarter of 2019 by modified retrospective method. The presentation and disclosure guidance are applied prospectively. Early adoption is permitted. We are currently assessing the potential impact to our consolidated financial statements. ASU 2016-06, Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments (a consensus of the Emerging Issues Task Force), provides clarification that determination of whether an embedded contingent put or call option in a financial instrument is clearly and closely related to the debt host requires only an analysis of the four-step decision sequence described in ASC 815-15-25-42. The Update was adopted in the first quarter of 2017 by modified retrospective application. This Update did not have a material effect on our consolidated financial statements. ASU 2016-05, Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships (a consensus of the Emerging Issues Task Force), clarifies that a change in counterparty to a derivative instrument that has been designated as a hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided all other hedge accounting criteria continue to be met. The Update was adopted in the first quarter of 2017 by prospective application. This Update did not have a material effect on our consolidated financial statements. Extinguishments of Liabilities ASU 2016-04, Liabilities—Extinguishments of Liabilities (Subtopic 405-20): Recognition of Breakage for Certain Prepaid Stored-Value Products (a consensus of the Emerging Issues Task Force), requires entities that sell prepaid stored-value products redeemable for goods, services or cash at third-party merchants to recognize breakage. The Update is effective in the first quarter of 2018 with either the modified retrospective method by means of a cumulative-effect adjustment to retained earnings or retrospective application. Early adoption is permitted. This Update is not expected to have a material effect on our consolidated financial statements. Leases ASU 2016-02, Leases (Topic 842), requires lessees to put most leases on their balance sheets but recognize expenses in the income statement similar to current accounting. In addition, the Update changes the guidance for sale-leaseback transactions, initial direct costs and lease executory costs for most entities. All entities will classify leases to determine how to recognize lease related revenue and expense. The Update is effective in the first quarter of 2019 with modified retrospective application including a number of optional practical expedients. Early adoption is permitted. We are currently assessing the potential impact to our consolidated financial statements. Financial Instruments – Recognition and Measurement ASU 2016-01, Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, amends the presentation and accounting for certain financial instruments, including liabilities measured at fair value under the fair value option, and equity investments. The guidance also updates fair value presentation and disclosure requirements for financial instruments measured at amortized cost. The Update is effective in the first quarter of 2018 with a cumulative-effect adjustment as of the beginning of the fiscal year of adoption. Early adoption is prohibited except for the provision requiring the recognition of changes in fair value related to changes in an entity’s own credit risk in other comprehensive income for financial liabilities measured using the fair value option. This Update is not expected to have a material effect on our consolidated financial statements.

Mergers and Acquisitions (Table

Mergers and Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Acquisition [Line Items]
Amounts Recorded on Consolidated Balance Sheets in Conjunction with Acquisition	The following table summarizes the amounts recorded on the consolidated balance sheets as of each of the acquisition dates in conjunction with the acquisitions discussed above: (in thousands) YDKN Fifth Third Branches METR BofA Branches Fair value of consideration paid $ 1,784,783 $ — $ 404,242 $ — Fair value of identifiable assets acquired: Cash and cash equivalents 196,964 198,872 46,890 148,159 Securities 940,272 — 722,980 — Loans 5,114,355 95,354 1,862,447 842 Core deposit and other intangible assets 69,555 4,129 24,163 3,000 Fixed and other assets 461,293 14,069 127,185 1,133 Total identifiable assets acquired 6,782,439 312,424 2,783,665 153,134 Fair value of liabilities assumed: Deposits 5,176,915 302,529 2,328,238 154,619 Borrowings 969,385 — 227,539 — Other liabilities 68,264 24,041 8,700 — Total liabilities assumed 6,214,564 326,570 2,564,477 154,619 Fair value of net identifiable assets acquired 567,875 (14,146 ) 219,188 (1,485 ) Goodwill recognized (1) $ 1,216,908 $ 14,146 $ 185,054 $ 1,485 (1) All of the goodwill for these transactions has been recorded in the Community Banking segment.
Yadkin Financial Corporation (YDKN)
Business Acquisition [Line Items]
Measurement period adjustments	The following table presents the provisional estimate and fair value amounts recorded for certain acquired items: (in thousands) Acquired Asset or Liability Balance Sheet Line Item Provisional Estimate Fair Value Increase (Decrease) Loans and leases Loans and leases, net $ 5,116,497 $ 5,114,355 $ (2,142 ) Premises and equipment Premises and equipment, net 95,208 70,031 (25,177 ) Deferred taxes Other assets 94,307 125,100 30,793 Other liabilities Other liabilities 70,761 68,264 (2,497 )
Business Acquisition Pro Forma Information	The following pro forma financial information for the periods presented reflects our estimated consolidated pro forma results of operations as if the YDKN acquisition occurred on January 1, 2016, unadjusted for potential cost savings and other business synergies we expect to receive as a result of the acquisition: (dollars in thousands, except per share data) FNB YDKN Pro Forma Adjustments Pro Forma Combined Twelve Months Ended December 31, 2017 Revenue (net interest income and non-interest income) $ 1,077,984 $ 74,574 $ 3,419 $ 1,155,977 Net income 227,478 22,435 (1,165 ) 248,748 Net income available to common stockholders 219,437 22,435 (1,165 ) 240,707 Earnings per common share – basic 0.92 0.78 — 0.80 Earnings per common share – diluted 0.91 0.77 — 0.79 Twelve Months Ended December 31, 2016 Revenue $ 813,273 $ 293,655 $ (5,290 ) $ 1,101,638 Net income 170,891 55,168 (7,862 ) 218,197 Net income available to common stockholders 162,850 55,168 (7,862 ) 210,156 Earnings per common share – basic 0.79 1.15 — 0.67 Earnings per common share – diluted 0.78 1.14 — 0.67

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Cost and Fair Value of Securities Available for Sale	The amortized cost and fair value of securities are as follows: (in thousands) Amortized Gross Unrealized Gains Gross Unrealized Losses Fair Value Securities Available for Sale (AFS): December 31, 2017 U.S. Treasury $ — $ — $ — $ — U.S. government-sponsored entities 347,767 52 (3,877 ) 343,942 Residential mortgage-backed securities: Agency mortgage-backed securities 1,615,168 1,225 (17,519 ) 1,598,874 Agency collateralized mortgage obligations 813,034 — (18,077 ) 794,957 Non-agency collateralized mortgage obligations 1 — — 1 Commercial mortgage-backed securities — — — — States of the U.S. and political subdivisions 21,151 6 (64 ) 21,093 Other debt securities 4,913 — (243 ) 4,670 Total debt securities 2,802,034 1,283 (39,780 ) 2,763,537 Equity securities 587 438 — 1,025 Total securities available for sale $ 2,802,621 $ 1,721 $ (39,780 ) $ 2,764,562 December 31, 2016 U.S. Treasury $ 29,874 $ 79 $ — $ 29,953 U.S. government-sponsored entities 367,604 864 (3,370 ) 365,098 Residential mortgage-backed securities: Agency mortgage-backed securities 1,267,535 2,257 (16,994 ) 1,252,798 Agency collateralized mortgage obligations 546,659 419 (11,104 ) 535,974 Non-agency collateralized mortgage obligations 891 6 — 897 Commercial mortgage-backed securities 1,292 — (1 ) 1,291 States of the U.S. and political subdivisions 36,065 86 (302 ) 35,849 Other debt securities 9,828 94 (435 ) 9,487 Total debt securities 2,259,748 3,805 (32,206 ) 2,231,347 Equity securities 273 367 — 640 Total securities available for sale $ 2,260,021 $ 4,172 $ (32,206 ) $ 2,231,987
Schedule of Amortized Cost and Fair Value of Securities Held to Maturity	(in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Securities Held to Maturity (HTM): December 31, 2017 U.S. Treasury $ 500 $ 134 $ — $ 634 U.S. government-sponsored entities 247,310 93 (4,388 ) 243,015 Residential mortgage-backed securities: Agency mortgage-backed securities 1,219,802 3,475 (9,058 ) 1,214,219 Agency collateralized mortgage obligations 777,146 32 (20,095 ) 757,083 Non-agency collateralized mortgage obligations — — — — Commercial mortgage-backed securities 80,786 414 (575 ) 80,625 States of the U.S. and political subdivisions 916,724 13,209 (7,130 ) 922,803 Total securities held to maturity $ 3,242,268 $ 17,357 $ (41,246 ) $ 3,218,379 December 31, 2016 U.S. Treasury $ 500 $ 137 $ — $ 637 U.S. government-sponsored entities 272,645 348 (4,475 ) 268,518 Residential mortgage-backed securities: Agency mortgage-backed securities 852,215 5,654 (8,645 ) 849,224 Agency collateralized mortgage obligations 743,148 447 (17,801 ) 725,794 Non-agency collateralized mortgage obligations 1,689 3 (6 ) 1,686 Commercial mortgage-backed securities 49,797 181 (226 ) 49,752 States of the U.S. and political subdivisions 417,348 1,456 (19,638 ) 399,166 Total securities held to maturity $ 2,337,342 $ 8,226 $ (50,791 ) $ 2,294,777
Gross Gains and Gross Losses Realized on Sales of Securities	Gross gains and gross losses were realized on securities as follows: Year Ended December 31 2017 2016 2015 (in thousands) Gross gains $ 6,866 $ 713 $ 831 Gross losses (950 ) (1 ) (9 ) Net gains $ 5,916 $ 712 $ 822
Amortized Cost and Fair Value of Securities, by Contractual Maturities	As of December 31, 2017 , the amortized cost and fair value of securities, by contractual maturities, were as follows: Available for Sale Held to Maturity (in thousands) Amortized Cost Fair Value Amortized Cost Fair Value Due in one year or less $ 81,819 $ 81,594 $ 30,438 $ 30,254 Due from one to five years 278,153 274,516 225,054 220,921 Due from five to ten years 10,892 10,795 81,650 82,672 Due after ten years 2,967 2,800 827,392 832,605 373,831 369,705 1,164,534 1,166,452 Residential mortgage-backed securities: Agency mortgage-backed securities 1,615,168 1,598,874 1,219,802 1,214,219 Agency collateralized mortgage obligations 813,034 794,957 777,146 757,083 Non-agency collateralized mortgage obligations 1 1 — — Commercial mortgage-backed securities — — 80,786 80,625 Equity securities 587 1,025 — — Total securities $ 2,802,621 $ 2,764,562 $ 3,242,268 $ 3,218,379
Schedule of Securities Pledged as Collateral	Following is information relating to securities pledged: December 31 2017 2016 (dollars in thousands) Securities pledged (carrying value): To secure public deposits, trust deposits and for other purposes as required by law $ 3,491,634 $ 2,779,335 As collateral for short-term borrowings 263,756 322,038 Securities pledged as a percent of total securities 62.5 % 67.9 %
Summaries of Fair Values and Unrealized Losses of Securities, Segregated by Length of Impairment	Following are summaries of the fair values and unrealized losses of temporarily impaired securities, segregated by length of impairment: Less than 12 Months 12 Months or More Total (dollars in thousands) # Fair Value Unrealized Losses # Fair Value Unrealized Losses # Fair Value Unrealized Losses Securities Available for Sale: December 31, 2017 U.S. government-sponsored entities 7 $ 106,809 $ (363 ) 10 $ 201,485 $ (3,514 ) 17 $ 308,294 $ (3,877 ) Residential mortgage-backed securities: Agency mortgage-backed securities 43 976,738 (7,723 ) 28 473,625 (9,796 ) 71 1,450,363 (17,519 ) Agency collateralized mortgage obligations 14 409,005 (6,231 ) 33 335,452 (11,846 ) 47 744,457 (18,077 ) Non-agency collateralized mortgage obligations — — — — — — — — — Commercial mortgage-backed securities — — — — — — — — — States of the U.S. and political subdivisions 7 11,254 (55 ) 1 879 (9 ) 8 12,133 (64 ) Other debt securities — — — 3 4,670 (243 ) 3 4,670 (243 ) Equity securities — — — — — — — — — Total temporarily impaired securities AFS 71 $ 1,503,806 $ (14,372 ) 75 $ 1,016,111 $ (25,408 ) 146 $ 2,519,917 $ (39,780 ) December 31, 2016 U.S. government-sponsored entities 11 $ 211,636 $ (3,370 ) — $ — $ — 11 $ 211,636 $ (3,370 ) Residential mortgage-backed securities: Agency mortgage-backed securities 55 1,056,731 (16,994 ) — — — 55 1,056,731 (16,994 ) Agency collateralized mortgage obligations 26 346,662 (7,261 ) 9 89,040 (3,843 ) 35 435,702 (11,104 ) Commercial mortgage-backed securities 1 1,291 (1 ) — — — 1 1,291 (1 ) States of the U.S. and political subdivisions 20 28,631 (302 ) — — — 20 28,631 (302 ) Other debt securities — — — 3 4,470 (435 ) 3 4,470 (435 ) Total temporarily impaired securities AFS 113 $ 1,644,951 $ (27,928 ) 12 $ 93,510 $ (4,278 ) 125 $ 1,738,461 $ (32,206 ) Less than 12 Months 12 Months or More Total (dollars in thousands) # Fair Value Unrealized Losses # Fair Value Unrealized Losses # Fair Value Unrealized Losses Securities Held to Maturity: December 31, 2017 U.S. government-sponsored entities 4 $ 54,790 $ (239 ) 10 $ 185,851 $ (4,149 ) 14 $ 240,641 $ (4,388 ) Residential mortgage-backed securities: Agency mortgage-backed securities 36 648,485 (4,855 ) 11 183,989 (4,203 ) 47 832,474 (9,058 ) Agency collateralized mortgage obligations 14 275,290 (1,701 ) 35 473,257 (18,394 ) 49 748,547 (20,095 ) Non-agency collateralized mortgage obligations — — — — — — — — — Commercial mortgage-backed securities 3 26,399 (123 ) 2 19,443 (452 ) 5 45,842 (575 ) States of the U.S. and political subdivisions 16 56,739 (933 ) 37 121,536 (6,197 ) 53 178,275 (7,130 ) Total temporarily impaired securities HTM 73 $ 1,061,703 $ (7,851 ) 95 $ 984,076 $ (33,395 ) 168 $ 2,045,779 $ (41,246 ) December 31, 2016 U.S. government-sponsored entities 10 $ 185,525 $ (4,475 ) — $ — $ — 10 $ 185,525 $ (4,475 ) Residential mortgage-backed securities: Agency mortgage-backed securities 36 551,404 (8,645 ) — — — 36 551,404 (8,645 ) Agency collateralized mortgage obligations 29 516,237 (13,710 ) 12 112,690 (4,091 ) 41 628,927 (17,801 ) Non-agency collateralized mortgage obligations 3 1,128 (6 ) — — — 3 1,128 (6 ) Commercial mortgage-backed securities 1 12,317 (10 ) 1 8,267 (216 ) 2 20,584 (226 ) States of the U.S. and political subdivisions 94 247,301 (19,638 ) — — — 94 247,301 (19,638 ) Total temporarily impaired securities HTM 173 $ 1,513,912 $ (46,484 ) 13 $ 120,957 $ (4,307 ) 186 $ 1,634,869 $ (50,791 )
Summary of Cumulative Credit-Related OTTI Charges	The following table presents a summary of the cumulative credit-related OTTI charges recognized as components of earnings for securities for which a portion of an OTTI is recognized in other comprehensive income: (in thousands) Equities Total For the Year Ended December 31, 2016 Beginning balance $ 27 $ 27 Loss where impairment was not previously recognized — — Additional loss where impairment was previously recognized — — Reduction due to credit impaired securities sold (27 ) (27 ) Ending balance $ — $ —

Loans and Leases (Tables)

Loans and Leases (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Summary of Loans and Leases, Net of Unearned Income	Following is a summary of loans and leases, net of unearned income: (in thousands) Originated Loans and Leases Acquired Loans Total Loans and Leases December 31, 2017 Commercial real estate $ 5,174,783 $ 3,567,081 $ 8,741,864 Commercial and industrial 3,495,247 675,420 4,170,667 Commercial leases 266,720 — 266,720 Other 17,063 — 17,063 Total commercial loans and leases 8,953,813 4,242,501 13,196,314 Direct installment 1,755,713 149,822 1,905,535 Residential mortgages 2,036,226 666,465 2,702,691 Indirect installment 1,448,268 165 1,448,433 Consumer lines of credit 1,151,470 594,323 1,745,793 Total consumer loans 6,391,677 1,410,775 7,802,452 Total loans and leases, net of unearned income $ 15,345,490 $ 5,653,276 $ 20,998,766 December 31, 2016 Commercial real estate $ 4,095,817 $ 1,339,345 $ 5,435,162 Commercial and industrial 2,711,886 330,895 3,042,781 Commercial leases 196,636 — 196,636 Other 35,878 — 35,878 Total commercial loans and leases 7,040,217 1,670,240 8,710,457 Direct installment 1,765,257 79,142 1,844,399 Residential mortgages 1,446,776 397,798 1,844,574 Indirect installment 1,196,110 203 1,196,313 Consumer lines of credit 1,099,627 201,573 1,301,200 Total consumer loans 5,507,770 678,716 6,186,486 Total loans and leases, net of unearned income $ 12,547,987 $ 2,348,956 $ 14,896,943
Certain Information Relating to Regency Consumer Finance Loans	The following table shows certain information relating to the Regency consumer finance loans: December 31 2017 2016 (dollars in thousands) Regency consumer finance loans $ 174,916 $ 184,687 Percent of total loans and leases 0.8 % 1.2 %
Certain Information Relating to Commercial Real Estate Loans	The following table shows certain information relating to commercial real estate loans: December 31 2017 2016 (dollars in thousands) Commercial construction, acquisition and development loans $ 1,170,175 $ 597,617 Percent of total loans and leases 5.6 % 4.0 % Commercial real estate: Percent owner-occupied 35.3 % 36.2 % Percent non-owner-occupied 64.7 % 63.8 %
Summary of Loans to Related Parties	Following is a summary of the activity for these loans to related parties during 2017 : (in thousands) Balance at beginning of period $ 21,569 New loans 1,171 Repayments (3,447 ) Other 518 Balance at end of period $ 19,811
Summary of Outstanding Principal Balance and Carrying Amount of Acquired Loans	The outstanding balance and the carrying amount of acquired loans included in the consolidated balance sheets are as follows: December 31 2017 2016 (in thousands) Accounted for under ASC 310-30: Outstanding balance $ 5,176,015 $ 2,346,687 Carrying amount 4,834,256 2,015,904 Accounted for under ASC 310-20: Outstanding balance 835,130 342,015 Carrying amount 812,322 325,784 Total acquired loans: Outstanding balance 6,011,145 2,688,702 Carrying amount 5,646,578 2,341,688
Summary of Change in Accretable Yield of Acquired Loans	The following table provides changes in accretable yield for all acquired loans accounted for under ASC 310-30. Loans accounted for under ASC 310-20 are not included in this table. Year Ended December 31 2017 2016 (in thousands) Balance at beginning of period $ 467,070 $ 256,120 Acquisitions 444,715 308,312 Reduction due to unexpected early payoffs (127,949 ) (86,046 ) Reclass from non-accretable difference 155,840 92,823 Disposals/transfers (3,559 ) (409 ) Other (658 ) — Accretion (226,978 ) (103,730 ) Balance at end of period $ 708,481 $ 467,070
Summary of Acquisition of Purchased Loans	The following table reflects amounts at acquisition for all purchased loans subject to ASC 310-30 (impaired and non-impaired loans with deteriorated credit quality) acquired from YDKN in 2017 based on the fair value as described in Note 3. (in thousands) Acquired Impaired Loans Acquired Performing Loans Total Contractually required cash flows at acquisition $ 46,053 $ 5,085,712 $ 5,131,765 Non-accretable difference (expected losses and foregone interest) (23,924 ) (406,173 ) (430,097 ) Cash flows expected to be collected at acquisition 22,129 4,679,539 4,701,668 Accretable yield (3,266 ) (441,449 ) (444,715 ) Fair value of acquired loans at acquisition $ 18,863 $ 4,238,090 $ 4,256,953
Summary of Non-Performing Assets	Following is a summary of non-performing assets: December 31 2017 2016 (dollars in thousands) Non-accrual loans $ 74,635 $ 65,479 Troubled debt restructurings 23,481 20,428 Total non-performing loans 98,116 85,907 Other real estate owned (OREO) 40,606 32,490 Total non-performing assets $ 138,722 $ 118,397 Asset quality ratios: Non-performing loans / total loans and leases 0.47 % 0.58 % Non-performing loans + OREO / total loans and leases + OREO 0.66 % 0.79 % Non-performing assets / total assets 0.44 % 0.54 %
Age Analysis of Past Due Loans, by Class	The following tables provide an analysis of the aging of loans by class segregated by loans and leases originated and loans acquired: (in thousands) 30-89 Days Past Due ≥ 90 Days Past Due and Still Accruing Non- Accrual Total Past Due Current Total Loans and Leases Originated Loans and Leases December 31, 2017 Commercial real estate $ 8,273 $ 1 $ 24,773 $ 33,047 $ 5,141,736 $ 5,174,783 Commercial and industrial 8,948 3 17,077 26,028 3,469,219 3,495,247 Commercial leases 1,382 41 1,574 2,997 263,723 266,720 Other 83 153 1,000 1,236 15,827 17,063 Total commercial loans and leases 18,686 198 44,424 63,308 8,890,505 8,953,813 Direct installment 13,192 4,466 8,896 26,554 1,729,159 1,755,713 Residential mortgages 14,096 2,832 5,771 22,699 2,013,527 2,036,226 Indirect installment 10,313 611 2,240 13,164 1,435,104 1,448,268 Consumer lines of credit 5,859 1,014 2,313 9,186 1,142,284 1,151,470 Total consumer loans 43,460 8,923 19,220 71,603 6,320,074 6,391,677 Total originated loans and leases $ 62,146 $ 9,121 $ 63,644 $ 134,911 $ 15,210,579 $ 15,345,490 December 31, 2016 Commercial real estate $ 8,452 $ 1 $ 20,114 $ 28,567 $ 4,067,250 $ 4,095,817 Commercial and industrial 16,019 3 24,141 40,163 2,671,723 2,711,886 Commercial leases 973 1 3,429 4,403 192,233 196,636 Other 398 83 1,000 1,481 34,397 35,878 Total commercial loans and leases 25,842 88 48,684 74,614 6,965,603 7,040,217 Direct installment 10,573 4,386 6,484 21,443 1,743,814 1,765,257 Residential mortgages 10,594 3,014 3,316 16,924 1,429,852 1,446,776 Indirect installment 9,312 513 1,983 11,808 1,184,302 1,196,110 Consumer lines of credit 3,529 1,112 1,616 6,257 1,093,370 1,099,627 Total consumer loans 34,008 9,025 13,399 56,432 5,451,338 5,507,770 Total originated loans and leases $ 59,850 $ 9,113 $ 62,083 $ 131,046 $ 12,416,941 $ 12,547,987 (in thousands) 30-89 Days Past Due ≥ 90 Days Past Due and Still Accruing Non- Accrual Total Past Due (1)(2) Current (Discount)/ Premium Total Loans Acquired Loans December 31, 2017 Commercial real estate $ 34,928 $ 63,092 $ 3,975 $ 101,995 $ 3,657,152 $ (192,066 ) $ 3,567,081 Commercial and industrial 3,187 6,452 5,663 15,302 698,265 (38,147 ) 675,420 Total commercial loans 38,115 69,544 9,638 117,297 4,355,417 (230,213 ) 4,242,501 Direct installment 5,267 2,013 — 7,280 141,386 1,156 149,822 Residential mortgages 17,191 15,139 — 32,330 675,499 (41,364 ) 666,465 Indirect installment — 1 — 1 10 154 165 Consumer lines of credit 6,353 3,253 1,353 10,959 596,298 (12,934 ) 594,323 Total consumer loans 28,811 20,406 1,353 50,570 1,413,193 (52,988 ) 1,410,775 Total acquired loans $ 66,926 $ 89,950 $ 10,991 $ 167,867 $ 5,768,610 $ (283,201 ) $ 5,653,276 December 31, 2016 Commercial real estate $ 9,501 $ 23,890 $ 949 $ 34,340 $ 1,384,752 $ (79,747 ) $ 1,339,345 Commercial and industrial 1,789 2,942 2,111 6,842 353,494 (29,441 ) 330,895 Total commercial loans 11,290 26,832 3,060 41,182 1,738,246 (109,188 ) 1,670,240 Direct installment 2,317 1,344 — 3,661 73,479 2,002 79,142 Residential mortgages 8,428 10,816 — 19,244 416,561 (38,007 ) 397,798 Indirect installment 19 4 — 23 96 84 203 Consumer lines of credit 2,156 1,528 336 4,020 201,958 (4,405 ) 201,573 Total consumer loans 12,920 13,692 336 26,948 692,094 (40,326 ) 678,716 Total acquired loans $ 24,210 $ 40,524 $ 3,396 $ 68,130 $ 2,430,340 $ (149,514 ) $ 2,348,956 (1) Past due information for acquired loans is based on the contractual balance outstanding at December 31, 2017 and 2016 . (2) Acquired loans are considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of expected cash flows on such loans. In these instances, we do not consider acquired contractually delinquent loans to be non-accrual or non-performing and continue to recognize interest income on these loans using the accretion method. Acquired loans are considered non-accrual or non-performing when, due to credit deterioration or other factors, we determine we are no longer able to reasonably estimate the timing and amount of expected cash flows on such loans. We do not recognize interest income on acquired loans considered non-accrual or non-performing.
Summary of Commercial Loans by Credit Quality	The following tables present a summary of our commercial loans and leases by credit quality category segregated by loans and leases originated and loans acquired: Commercial Loan and Lease Credit Quality Categories (in thousands) Pass Special Mention Substandard Doubtful Total Originated Loans and Leases December 31, 2017 Commercial real estate $ 4,922,872 $ 152,744 $ 98,728 $ 439 $ 5,174,783 Commercial and industrial 3,266,966 132,975 92,091 3,215 3,495,247 Commercial leases 260,235 4,425 2,060 — 266,720 Other 15,866 43 1,154 — 17,063 Total originated commercial loans and leases $ 8,465,939 $ 290,187 $ 194,033 $ 3,654 $ 8,953,813 December 31, 2016 Commercial real estate $ 3,895,764 $ 130,452 $ 69,588 $ 13 $ 4,095,817 Commercial and industrial 2,475,955 104,652 128,089 3,190 2,711,886 Commercial leases 188,662 3,789 4,185 — 196,636 Other 34,531 264 1,083 — 35,878 Total originated commercial loans and leases $ 6,594,912 $ 239,157 $ 202,945 $ 3,203 $ 7,040,217 Acquired Loans December 31, 2017 Commercial real estate $ 3,102,788 $ 250,987 $ 213,089 $ 217 $ 3,567,081 Commercial and industrial 603,611 26,059 45,661 89 675,420 Total acquired commercial loans $ 3,706,399 $ 277,046 $ 258,750 $ 306 $ 4,242,501 December 31, 2016 Commercial real estate $ 1,144,676 $ 85,894 $ 108,128 $ 647 $ 1,339,345 Commercial and industrial 274,819 20,593 34,967 516 330,895 Total acquired commercial loans $ 1,419,495 $ 106,487 $ 143,095 $ 1,163 $ 1,670,240
Summary of Consumer Loans by Payment Status	Following is a table showing consumer loans by payment status: Consumer Loan Credit Quality by Payment Status (in thousands) Performing Non-Performing Total Originated loans December 31, 2017 Direct installment $ 1,739,060 $ 16,653 $ 1,755,713 Residential mortgages 2,019,816 16,410 2,036,226 Indirect installment 1,445,833 2,435 1,448,268 Consumer lines of credit 1,147,576 3,894 1,151,470 Total originated consumer loans $ 6,352,285 $ 39,392 $ 6,391,677 December 31, 2016 Direct installment $ 1,750,305 $ 14,952 $ 1,765,257 Residential mortgages 1,433,409 13,367 1,446,776 Indirect installment 1,193,930 2,180 1,196,110 Consumer lines of credit 1,096,642 2,985 1,099,627 Total originated consumer loans $ 5,474,286 $ 33,484 $ 5,507,770 Acquired loans December 31, 2017 Direct installment $ 149,751 $ 71 $ 149,822 Residential mortgages 666,465 — 666,465 Indirect installment 165 — 165 Consumer lines of credit 592,384 1,939 594,323 Total acquired consumer loans $ 1,408,765 $ 2,010 $ 1,410,775 December 31, 2016 Direct installment $ 79,142 $ — $ 79,142 Residential mortgages 397,798 — 397,798 Indirect installment 203 — 203 Consumer lines of credit 201,061 512 201,573 Total acquired consumer loans $ 678,204 $ 512 $ 678,716
Summary of Impaired Loans and Leases, by Class	Following is a summary of information pertaining to originated loans and leases considered to be impaired, by class of loan and lease: (in thousands) Unpaid Contractual Principal Balance Recorded Investment With No Specific Reserve Recorded Investment With Specific Reserve Total Recorded Investment Specific Reserve Average Recorded Investment At or for the Year Ended Commercial real estate $ 27,718 $ 21,748 $ 2,906 $ 24,654 $ 439 $ 24,413 Commercial and industrial 29,307 11,595 4,457 16,052 3,215 23,907 Commercial leases 1,574 1,574 — 1,574 — 1,386 Other — — — — — — Total commercial loans and leases 58,599 34,917 7,363 42,280 3,654 49,706 Direct installment 19,375 16,653 — 16,653 — 16,852 Residential mortgages 17,754 16,410 — 16,410 — 15,984 Indirect installment 5,709 2,435 — 2,435 — 2,279 Consumer lines of credit 5,039 3,894 — 3,894 — 3,815 Total consumer loans 47,877 39,392 — 39,392 — 38,930 Total $ 106,476 $ 74,309 $ 7,363 $ 81,672 $ 3,654 $ 88,636 At or for the Year Ended Commercial real estate $ 23,771 $ 19,699 $ 464 $ 20,163 $ 13 $ 19,217 Commercial and industrial 25,719 14,781 8,996 23,777 3,190 29,730 Commercial leases 3,429 3,429 — 3,429 — 3,394 Other 1,000 1,000 — 1,000 — 1,000 Total commercial loans and leases 53,919 38,909 9,460 48,369 3,203 53,341 Direct installment 16,440 14,952 — 14,952 — 14,997 Residential mortgages 14,090 13,367 — 13,367 — 13,200 Indirect installment 5,172 2,180 — 2,180 — 2,037 Consumer lines of credit 3,858 2,985 — 2,985 — 2,813 Total consumer loans 39,560 33,484 — 33,484 — 33,047 Total $ 93,479 $ 72,393 $ 9,460 $ 81,853 $ 3,203 $ 86,388
Additional Allowance for Credit Losses Relating to Acquired Loans	Following is a summary of the allowance for credit losses required for acquired loans due to changes in credit quality subsequent to the acquisition date: December 31 2017 2016 (in thousands) Commercial real estate $ 4,976 $ 4,538 Commercial and industrial (415 ) 500 Total commercial loans 4,561 5,038 Direct installment 1,553 1,005 Residential mortgages 484 632 Indirect installment 177 221 Consumer lines of credit (77 ) 372 Total consumer loans 2,137 2,230 Total allowance on acquired loans $ 6,698 $ 7,268
Summary of Composition of Total TDRs	Following is a summary of the composition of total TDRs: (in thousands) Originated Acquired Total December 31, 2017 Accruing: Performing $ 19,538 $ 266 $ 19,804 Non-performing 20,173 3,308 23,481 Non-accrual 10,472 234 10,706 Total TDRs $ 50,183 $ 3,808 $ 53,991 December 31, 2016 Accruing: Performing $ 17,105 $ 365 $ 17,470 Non-performing 20,252 176 20,428 Non-accrual 9,035 — 9,035 Total TDRs $ 46,392 $ 541 $ 46,933
Reserve for Commercial TDRs Included in Allowance for Credit Losses	The reserve for commercial TDRs included in the allowance for credit losses is presented in the following table: December 31 2017 2016 (in thousands) Specific reserves for commercial TDRs $ 95 $ 291 Pooled reserves for individual commercial loans under $500 469 276
Summary of Troubled Debt Restructurings by Class of Loans	The majority of TDRs are the result of interest rate concessions for a limited period of time. Following is a summary of loans, by class, that have been restructured: Year Ended December 31 2017 2016 (dollars in thousands) Number of Contracts Pre-Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Number of Contracts Pre-Modification Outstanding Recorded Investment Post- Modification Outstanding Recorded Investment Commercial real estate 3 $ 1,608 $ 1,683 4 $ 778 $ 737 Commercial and industrial 3 3,568 3,091 3 1,727 1,504 Total commercial loans 6 5,176 4,774 7 2,505 2,241 Direct installment 641 5,107 4,500 527 6,090 5,566 Residential mortgages 43 2,251 2,095 45 2,155 2,081 Indirect installment 18 48 43 19 51 51 Consumer lines of credit 64 1,372 1,158 81 1,419 1,283 Total consumer loans 766 8,778 7,796 672 9,715 8,981 Total 772 $ 13,954 $ 12,570 679 $ 12,220 $ 11,222
Summary of Originated Troubled Debt Restructurings by Class of Loans and Leases, Payment Default	Following is a summary of originated TDRs, by class, for which there was a payment default, excluding loans that were either charged-off or cured by period end. Default occurs when a loan is 90 days or more past due and is within 12 months of restructuring. Year Ended December 31 2017 2016 (dollars in thousands) Number of Contracts Recorded Investment Number of Contracts Recorded Investment Commercial real estate 1 $ 463 — $ — Commercial and industrial — — — — Total commercial loans 1 463 — — Direct installment 131 358 90 313 Residential mortgages 6 314 7 285 Indirect installment 17 28 18 35 Consumer lines of credit 5 170 3 394 Total consumer loans 159 870 118 1,027 Total 160 $ 1,333 118 $ 1,027

Allowance for Credit Losses (Ta

Allowance for Credit Losses (Tables)	12 Months Ended
	Dec. 31, 2017
Receivables [Abstract]
Summary of Changes in Allowance for Credit Losses by Loan and Lease Class	Following is a summary of changes in the allowance for credit losses, by loan and lease class: (in thousands) Balance at Beginning of Year Charge- Offs Recoveries Net Charge- Offs Provision for Credit Losses Balance at End of Year Year Ended December 31, 2017 Commercial real estate $ 46,635 $ (2,178 ) $ 2,311 $ 133 $ 3,513 $ 50,281 Commercial and industrial 47,991 (26,188 ) 1,275 (24,913 ) 28,885 51,963 Commercial leases 3,280 (1,017 ) 6 (1,011 ) 3,377 5,646 Other 1,392 (4,099 ) 1,255 (2,844 ) 3,295 1,843 Total commercial loans and leases 99,298 (33,482 ) 4,847 (28,635 ) 39,070 109,733 Direct installment 21,391 (12,401 ) 2,015 (10,386 ) 9,931 20,936 Residential mortgages 10,082 (595 ) 184 (411 ) 5,836 15,507 Indirect installment 10,564 (9,201 ) 3,708 (5,493 ) 6,896 11,967 Consumer lines of credit 9,456 (2,204 ) 461 (1,743 ) 2,826 10,539 Total consumer loans 51,493 (24,401 ) 6,368 (18,033 ) 25,489 58,949 Total allowance on originated loans 150,791 (57,883 ) 11,215 (46,668 ) 64,559 168,682 Purchased credit-impaired loans 572 (469 ) 36 (433 ) 496 635 Other acquired loans 6,696 (1,233 ) 4,582 3,349 (3,982 ) 6,063 Total allowance on acquired loans 7,268 (1,702 ) 4,618 2,916 (3,486 ) 6,698 Total allowance $ 158,059 $ (59,585 ) $ 15,833 $ (43,752 ) $ 61,073 $ 175,380 Year Ended December 31, 2016 Commercial real estate $ 41,741 $ (6,657 ) $ 3,669 $ (2,988 ) $ 7,882 $ 46,635 Commercial and industrial 41,023 (19,584 ) 2,508 (17,076 ) 24,044 47,991 Commercial leases 2,541 (962 ) 66 (896 ) 1,635 3,280 Other 1,013 (2,729 ) 131 (2,598 ) 2,977 1,392 Total commercial loans and leases 86,318 (29,932 ) 6,374 (23,558 ) 36,538 99,298 Direct installment 21,587 (10,153 ) 1,822 (8,331 ) 8,135 21,391 Residential mortgages 7,909 (441 ) 74 (367 ) 2,540 10,082 Indirect installment 9,889 (7,855 ) 2,015 (5,840 ) 6,515 10,564 Consumer lines of credit 9,582 (2,085 ) 265 (1,820 ) 1,694 9,456 Total consumer loans 48,967 (20,534 ) 4,176 (16,358 ) 18,884 51,493 Total allowance on originated loans 135,285 (50,466 ) 10,550 (39,916 ) 55,422 150,791 Purchased credit-impaired loans 834 (399 ) 42 (357 ) 95 572 Other acquired loans 5,893 (649 ) 1,217 568 235 6,696 Total allowance on acquired loans 6,727 (1,048 ) 1,259 211 330 7,268 Total allowance $ 142,012 $ (51,514 ) $ 11,809 $ (39,705 ) $ 55,752 $ 158,059 Year Ended December 31, 2015 Commercial real estate $ 37,588 $ (4,443 ) $ 1,117 $ (3,326 ) $ 7,479 $ 41,741 Commercial and industrial 32,645 (3,562 ) 1,773 (1,789 ) 10,167 41,023 Commercial leases 2,398 (544 ) 101 (443 ) 586 2,541 Other 759 (1,691 ) 55 (1,636 ) 1,890 1,013 Total commercial loans and leases 73,390 (10,240 ) 3,046 (7,194 ) 20,122 86,318 Direct installment 20,538 (10,844 ) 1,527 (9,317 ) 10,366 21,587 Residential mortgages 8,024 (1,010 ) 85 (925 ) 810 7,909 Indirect installment 7,504 (6,427 ) 1,190 (5,237 ) 7,622 9,889 Consumer lines of credit 8,496 (1,653 ) 175 (1,478 ) 2,564 9,582 Total consumer loans 44,562 (19,934 ) 2,977 (16,957 ) 21,362 48,967 Total allowance on originated loans 117,952 (30,174 ) 6,023 (24,151 ) 41,484 135,285 Purchased credit-impaired loans 660 (64 ) 19 (45 ) 219 834 Other acquired loans 7,314 (830 ) 671 (159 ) (1,262 ) 5,893 Total allowance on acquired loans 7,974 (894 ) 690 (204 ) (1,043 ) 6,727 Total allowance $ 125,926 $ (31,068 ) $ 6,713 $ (24,355 ) $ 40,441 $ 142,012
Summary of Individual and Collective Allowance for Credit Losses and Loan and Lease Balances by Class	Following is a summary of the individual and collective originated allowance for credit losses and corresponding originated loan and lease balances by class: Originated Allowance Originated Loans and Leases Outstanding (in thousands) Individually Evaluated for Impairment Collectively Evaluated for Impairment Loans and Leases Individually Evaluated for Impairment Collectively Evaluated for Impairment December 31, 2017 Commercial real estate $ 439 $ 49,842 $ 5,174,783 $ 11,114 $ 5,163,669 Commercial and industrial 3,215 48,748 3,495,247 9,872 3,485,375 Commercial leases — 5,646 266,720 — 266,720 Other — 1,843 17,063 — 17,063 Total commercial loans and leases 3,654 106,079 8,953,813 20,986 8,932,827 Direct installment — 20,936 1,755,713 — 1,755,713 Residential mortgages — 15,507 2,036,226 — 2,036,226 Indirect installment — 11,967 1,448,268 — 1,448,268 Consumer lines of credit — 10,539 1,151,470 — 1,151,470 Total consumer loans — 58,949 6,391,677 — 6,391,677 Total $ 3,654 $ 165,028 $ 15,345,490 $ 20,986 $ 15,324,504 December 31, 2016 Commercial real estate $ 13 $ 46,622 $ 4,095,817 $ 12,973 $ 4,082,844 Commercial and industrial 3,190 44,801 2,711,886 21,746 2,690,140 Commercial leases — 3,280 196,636 — 196,636 Other — 1,392 35,878 — 35,878 Total commercial loans and leases 3,203 96,095 7,040,217 34,719 7,005,498 Direct installment — 21,391 1,765,257 — 1,765,257 Residential mortgages — 10,082 1,446,776 — 1,446,776 Indirect installment — 10,564 1,196,110 — 1,196,110 Consumer lines of credit — 9,456 1,099,627 — 1,099,627 Total consumer loans — 51,493 5,507,770 — 5,507,770 Total $ 3,203 $ 147,588 $ 12,547,987 $ 34,719 $ 12,513,268

Loan Servicing (Tables)

Loan Servicing (Tables)	12 Months Ended
	Dec. 31, 2017
Mortgage Loan
Servicing Assets at Fair Value [Line Items]
Servicing Asset at Amortized Cost	The unpaid principal balance of mortgage loans serviced for others, as of December 31, 2017 and 2016 , is listed below: December 31 2017 2016 (in thousands) Mortgage loans sold with servicing retained $ 3,256,548 $ 1,800,002 The following table summarizes activity relating to mortgage loans sold with servicing retained: Year Ended December 31 2017 2016 2015 (in thousands) Mortgage loans sold with servicing retained $ 1,769,129 $ 672,536 $ 431,617 Pretax gains resulting from above loan sales (1) 21,683 12,519 10,681 Mortgage servicing fees (1) 7,509 3,803 3,056 (1) Recorded in mortgage banking operations. Following is a summary of the MSR activity: Year Ended December 31 2017 2016 2015 (in thousands) Balance at beginning of period $ 13,521 $ 8,921 $ 6,859 Fair value of MSRs acquired 8,553 — — Additions 10,830 7,148 3,370 Payoffs and curtailments (1,491 ) (780 ) (694 ) Amortization (2,360 ) (1,768 ) (614 ) Balance at end of period $ 29,053 $ 13,521 $ 8,921 Fair value, beginning of period $ 17,546 $ 11,503 $ 8,684 Fair value, end of period 32,419 17,546 11,503
Schedule of Assumptions for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement	Following is a summary of the sensitivity of the fair value of MSRs to changes in key assumptions: December 31 2017 2016 (dollars in thousands) Weighted average life (months) 80.4 79.0 Constant prepayment rate (annualized) 9.9 % 9.9 % Discount rate 9.9 % 9.8 % Effect on fair value due to change in interest rates: +0.25% $ 1,737 $ 692 +0.50% 3,220 1,288 -0.25% (1,937 ) (789 ) -0.50% (4,007 ) (1,680 )
Small Business Administration Loans
Servicing Assets at Fair Value [Line Items]
Servicing Asset at Amortized Cost	The unpaid principal balance of SBA-guaranteed loans serviced for investors, as of December 31, 2017 , was as follows: December 31 2017 (in thousands) SBA loans sold to investors with servicing retained $ 305,977 The following table summarizes activity relating to SBA loans sold with servicing retained: Year Ended December 31 2017 (in thousands) SBA loans sold with servicing retained $ 53,938 Pretax gains resulting from above loan sales (1) 2,247 SBA servicing fees (1) 2,195 (1) Recorded in non-interest income. Following is a summary of the activity in SBA servicing assets: Year Ended December 31 2017 (in thousands) Balance at beginning of period $ — Fair value of servicing rights acquired 5,399 Additions 959 Impairment (charge) / recovery (281 ) Amortization (1,019 ) Balance at end of period $ 5,058 Fair value, beginning of period $ — Fair value, end of period 5,058
Schedule of Assumptions for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement	Following is a summary of key assumptions and the sensitivity of the SBA loan servicing rights to changes in these assumptions: December 31 2017 Decline in fair value due to (dollars in thousands) Actual 10% adverse change 20% adverse change 1% adverse change 2% adverse change Weighted-average life (months) 63.5 Constant prepayment rate 9.29 % $ (145 ) $ (284 ) $ — $ — Discount rate 14.87 — — (147 ) (286 )

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Summary of Premises and Equipment	Following is a summary of premises and equipment: December 31 2017 2016 (in thousands) Land $ 67,424 $ 45,640 Premises 239,807 186,784 Equipment 212,587 174,325 519,818 406,749 Accumulated depreciation (183,278 ) (162,793 ) Total premises and equipment, net $ 336,540 $ 243,956
Depreciation Expense for Premises and Equipment	Depreciation expense for premises and equipment is presented in the following table: December 31 2017 2016 2015 (in thousands) Depreciation expense for premises and equipment $ 34,322 $ 23,355 $ 20,009
Schedule of Rent Expense	Rental expense is presented in the following table: December 31 2017 2016 2015 (in thousands) Rental expense $ 29,148 $ 21,015 $ 16,193
Summary of Future Minimum Lease Payments	Following is a summary of future minimum lease payments for years following December 31, 2017 : (in thousands) 2018 $ 26,949 2019 22,995 2020 18,587 2021 15,358 2022 11,855 Later years 49,342 Total minimum rental commitment under leases $ 145,086

Goodwill and Other Intangible44

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Rollforward of Goodwill	The following table shows a rollforward of goodwill by line of business: (in thousands) Community Banking Wealth Manage- ment Insurance Consumer Finance Total Balance at January 1, 2016 $ 812,399 $ 8,020 $ 10,858 $ 1,809 $ 833,086 Goodwill (deductions) additions 199,200 — (157 ) — 199,043 Balance at December 31, 2016 1,011,599 8,020 10,701 1,809 1,032,129 Goodwill (deductions) additions 1,216,908 151 — — 1,217,059 Balance at December 31, 2017 $ 2,228,507 $ 8,171 $ 10,701 $ 1,809 $ 2,249,188
Summary of Core Deposit Intangibles, Customer Renewal Lists and Mortgage Servicing Rights	The following table shows a summary of core deposit intangibles and customer renewal lists: (in thousands) Core Deposit Intangibles Customer Renewal Lists Total December 31, 2017 Gross carrying amount $ 195,582 $ 12,442 $ 208,024 Accumulated amortization (106,938 ) (9,011 ) (115,949 ) Net carrying amount $ 88,644 $ 3,431 $ 92,075 December 31, 2016 Gross carrying amount $ 139,886 $ 12,352 $ 152,238 Accumulated amortization (89,888 ) (8,544 ) (98,432 ) Net carrying amount $ 49,998 $ 3,808 $ 53,806
Schedule of Amortization Expense Recognized	The following table summarizes amortization expense recognized: December 31 2017 2016 2015 (in thousands) Amortization expense $ 17,517 $ 11,210 $ 8,305
Schedule of Expected Amortization Expenses on Finite-Lived Intangible Assets	Following is a summary of the expected amortization expense on finite-lived intangible assets, assuming no new additions, for each of the five years following December 31, 2017 : (in thousands) 2018 $ 15,633 2019 13,532 2020 12,503 2021 11,339 2022 9,637 Total $ 62,644

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits [Abstract]
Summary of Deposits	Following is a summary of deposits: December 31 2017 2016 (in thousands) Non-interest-bearing demand $ 5,720,030 $ 4,205,337 Interest-bearing demand 9,571,038 6,931,381 Savings 2,488,178 2,352,434 Certificates and other time deposits: Less than $100,000 2,461,014 1,680,068 $100,000 through $250,000 1,326,562 642,509 Greater than $250,000 832,903 253,918 Total deposits $ 22,399,725 $ 16,065,647
Summary of Scheduled Maturities of Certificates and Other Time Deposits	Following is a summary of the scheduled maturities of certificates and other time deposits for the years following December 31, 2017 : (in thousands) 2018 $ 2,778,467 2019 1,026,222 2020 351,431 2021 194,678 2022 118,891 Later years 150,790 Total $ 4,620,479

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Summary of Short-Term Borrowings	Following is a summary of short-term borrowings: December 31 2017 2016 (in thousands) Securities sold under repurchase agreements $ 256,017 $ 313,062 Federal Home Loan Bank advances 2,285,000 1,025,000 Federal funds purchased 1,000,000 1,037,000 Subordinated notes 137,320 127,948 Total short-term borrowings $ 3,678,337 $ 2,503,010
Schedule of Weighted Average Interest Rates on Short-Term Borrowings	The following represents weighted average interest rates on short-term borrowings: December 31 2017 2016 2015 Year-to-date average 1.16 % 0.61 % 0.42 % Period-end 1.44 % 0.69 % 0.48 %

Long-Term Borrowings (Tables)

Long-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Summary of Long-Term Borrowings	Following is a summary of long-term borrowings: December 31 2017 2016 (in thousands) Federal Home Loan Bank advances $ 310,061 $ 305,110 Subordinated notes 87,614 87,147 Junior subordinated debt 110,347 48,600 Other subordinated debt 160,151 98,637 Total long-term borrowings $ 668,173 $ 539,494
Scheduled Annual Maturities for Long-Term Borrowings	Scheduled annual maturities for the long-term borrowings for the years following December 31, 2017 are as follows: (in thousands) 2018 $ 69,684 2019 151,558 2020 105,610 2021 52,189 2022 6,072 Later years 283,060 Total $ 668,173
Schedule of Weighted Average Interest Rate on Subordinated Notes	The weighted average interest rate on the subordinated notes are presented in the following table: December 31 2017 2016 2015 Subordinated notes weighted average interest rate 2.85 % 2.71 % 2.73 %
Junior Subordinated Debt Trusts	The following table provides information relating to the Trusts as of December 31, 2017 : (dollars in thousands) Trust Preferred Securities Common Securities Junior Subordinated Debt Stated Maturity Date Interest Rate Rate Reset Factor F.N.B. Statutory Trust II $ 21,500 $ 665 $ 22,165 6/15/2036 3.24 % LIBOR + 165 basis points (bps) Omega Financial Capital Trust I 26,000 1,114 26,473 10/18/2034 3.54 % LIBOR + 219 bps Yadkin Valley Statutory Trust I 25,000 774 20,863 12/15/2037 2.91 % LIBOR + 132 bps FNB Financial Services Capital Trust I 25,000 774 21,804 9/30/2035 2.80 % LIBOR + 146 bps American Community Capital Trust II 10,000 310 10,448 12/15/2033 4.14 % LIBOR + 280 bps Crescent Financial Capital Trust I 8,000 248 8,594 10/7/2033 4.46 % LIBOR + 310 bps Total $ 115,500 $ 3,885 $ 110,347

Derivative Instruments and He48

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative [Line Items]
Schedule of Notional Amounts and Gross Fair Values of Derivative Assets and Derivative Liabilities	The following table presents notional amounts and gross fair values of our derivative assets and derivative liabilities which are not offset in the balance sheet. December 31 2017 2016 Notional Amount Fair Value Notional Amount Fair Value (in thousands) Asset Liability Asset Liability Gross Derivatives Subject to master netting arrangements: Interest rate contracts – designated $ 705,000 $ 228 $ 1,982 $ 450,000 $ 9,256 $ 1,171 Interest rate swaps – not designated 2,245,442 1,169 11,599 1,689,157 12,720 34,046 Equity contracts – not designated 1,180 51 — 1,180 61 — Total subject to master netting arrangements 2,951,622 1,448 13,581 2,140,337 22,037 35,217 Not subject to master netting arrangements: Interest rate swaps – not designated 2,245,442 27,233 15,303 1,689,157 32,170 11,866 Interest rate lock commitments – not designated 88,107 1,594 5 — — — Forward delivery commitments – not designated 106,572 233 148 — — — Credit risk contracts – not designated 235,196 39 109 174,538 13 123 Equity contracts – not designated 1,180 — 51 1,180 — 61 Total not subject to master netting arrangements 2,676,497 29,099 15,616 1,864,875 32,183 12,050 Total $ 5,628,119 $ 30,547 $ 29,197 $ 4,005,212 $ 54,220 $ 47,267
Summary of Amounts Reclassified from Accumulated Other Comprehensive Income (AOCI)	The following table shows amounts reclassified from accumulated other comprehensive income (AOCI): December 31 2017 2016 (in thousands) Total Net of Tax Total Net of Tax Reclassified from AOCI to interest income $ 1,446 $ 940 $ 2,659 $ 1,728 Reclassified from AOCI to interest expense 1,374 893 703 457
Derivative Assets	The following table presents a reconciliation of the net amounts of derivative assets and derivative liabilities presented in the balance sheets to the net amounts that would result in the event of offset: Amount Not Offset in the (in thousands) Net Amount Financial Cash Net December 31, 2017 Derivative Assets Interest rate contracts: Designated $ 228 $ 228 $ — $ — Not designated 1,169 1,169 — — Equity contracts – not designated 51 51 — — Total $ 1,448 $ 1,448 $ — $ — December 31, 2016 Derivative Assets Interest rate contracts: Designated $ 9,256 $ 843 $ 8,413 $ — Not designated 12,720 474 12,132 114 Equity contracts – not designated 61 61 — — Total $ 22,037 $ 1,378 $ 20,545 $ 114
Derivative Liabilities	The following table presents a reconciliation of the net amounts of derivative assets and derivative liabilities presented in the balance sheets to the net amounts that would result in the event of offset: Amount Not Offset in the (in thousands) Net Amount Financial Cash Net Derivative Liabilities Interest rate contracts: Designated $ 1,982 $ 1,982 $ — $ — Not designated 11,599 10,940 — 659 Total $ 13,581 $ 12,922 $ — $ 659 Derivative Liabilities Interest rate contracts: Designated $ 1,171 $ 1,171 $ — $ — Not designated 34,046 15,490 17,651 905 Total $ 35,217 $ 16,661 $ 17,651 $ 905
Effect of Derivative Financial Instruments on Income Statement	The following table presents the effect of certain derivative financial instruments on the income statement: Year Ended December 31, (in thousands) Income Statement Location 2017 2016 Interest Rate Contracts Interest income – loans and leases $ 1,446 $ 2,659 Interest Rate Contracts Interest expense – short-term borrowings 1,374 703 Interest Rate Swaps Other income (592 ) (529 ) Credit Risk Contracts Other income 40 16
Designated as Hedging Instrument
Derivative [Line Items]
Summary of Key Data Related to Interest Rate	Following is a summary of key data related to interest rate contracts: December 31 2017 2016 (in thousands) Notional amount $ 705,000 $ 450,000 Fair value included in other assets 228 9,256 Fair value included in other liabilities 1,982 1,171
Not Designated as Hedging Instrument
Derivative [Line Items]
Summary of Key Data Related to Interest Rate	Following is a summary of key data related to interest rate swaps: December 31 2017 2016 (in thousands) Notional amount $ 4,490,884 $ 3,378,314 Fair value included in other assets 28,402 44,890 Fair value included in other liabilities 26,902 45,912

Commitments, Credit Risk and 49

Commitments, Credit Risk and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Summary of Off-Balance Sheet Credit Risk Information	Following is a summary of off-balance sheet credit risk information: December 31 2017 2016 (in thousands) Commitments to extend credit $ 6,957,822 $ 4,486,164 Standby letters of credit 132,904 117,732

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Issuance of Restricted Stock Awards and Aggregate Weighted Average Grant Date Fair Values	The following table details our issuance of restricted stock awards and the aggregate weighted average grant date fair values under these plans for the years indicated. As of December 31, 2017 , we had available up to 2,642,020 shares of common stock to issue under this Plan. (dollars in thousands) 2017 2016 2015 Restricted stock awards 713,998 574,125 664,337 Weighted average grant date fair values $ 10,474 $ 7,383 $ 8,802
Summary of Information Concerning Restricted Stock Awards	The following table summarizes the activity relating to restricted stock awards during the periods indicated: 2017 2016 2015 Awards Weighted Average Grant Price per Share Awards Weighted Average Grant Price per Share Awards Weighted Average Grant Price per Share Unvested awards outstanding at beginning of year 1,836,363 $ 12.97 1,548,444 $ 12.85 1,354,093 $ 11.86 Granted 713,998 14.67 574,125 12.86 664,337 13.25 Net adjustment due to performance (64,861 ) 13.85 72,070 11.79 13,115 19.74 Vested (542,580 ) 12.71 (384,704 ) 12.11 (484,010 ) 10.70 Forfeited/expired (31,018 ) 14.03 (31,394 ) 13.02 (41,130 ) 13.24 Dividend reinvestment 63,960 13.80 57,822 13.08 42,039 11.86 Unvested awards outstanding at end of year 1,975,862 13.64 1,836,363 12.97 1,548,444 12.85
Schedule of Certain Information Related to Restricted Stock Awards	The following table provides certain information relating to restricted stock awards: Year Ended December 31 2017 2016 2015 (in thousands) Stock-based compensation expense $ 8,201 $ 7,066 $ 4,461 Tax benefit related to stock-based compensation expense 2,870 2,473 1,561 Fair value of awards vested 8,106 4,587 6,070
Components of Restricted Stock Awards	The components of the restricted stock awards as of December 31, 2017 are as follows: (dollars in thousands) Service- Based Awards Performance- Based Awards Total Unvested restricted stock awards 1,062,902 912,960 1,975,862 Unrecognized compensation expense $ 7,037 $ 5,062 $ 12,099 Intrinsic value $ 14,689 $ 12,617 $ 27,306 Weighted average remaining life (in years) 1.93 1.72 1.83
Summary of Activity Related to Stock Options Awards	The following table summarizes the activity relating to stock options during the periods indicated: 2017 Weighted Average Exercise Price per Share 2016 Weighted Average Exercise Price per Share 2015 Weighted Average Exercise Price per Share Options outstanding at beginning of year 892,532 $ 8.95 435,340 $ 8.86 568,834 $ 8.86 Assumed from acquisitions 207,645 8.92 1,707,036 7.83 — — Exercised (255,503 ) 10.21 (1,128,075 ) 7.18 (93,822 ) 5.94 Forfeited/expired (122,024 ) 12.12 (121,769 ) 9.33 (39,672 ) 15.66 Options outstanding and exercisable at end of year 722,650 7.96 892,532 8.95 435,340 8.86
Summary of Stock Options Outstanding	The following table summarizes information about stock options outstanding at December 31, 2017 : Range of Exercise Prices Options Outstanding and Exercisable Weighted Average Remaining Contractual Years Weighted Average Exercise Price $3.45 - $5.18 162,224 3.07 $ 4.87 $5.19 - $7.78 118,707 3.31 6.84 $7.79 - $11.68 432,260 3.80 9.33 $11.69 - $14.53 9,459 0.69 12.48 722,650
Summary of Stock Options Exercised	The following table summarizes certain information relating to stock options exercised: Year Ended December 31 2017 2016 2015 (in thousands) Proceeds from stock options exercised $ 2,340 $ 7,816 $ 557 Tax benefit recognized from stock options exercised 385 1,862 130 Intrinsic value of stock options exercised 1,001 6,577 693

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Benefits [Abstract]
Schedule of Accumulated Benefit Obligation, Change in Benefit Obligation, Change in Plan Assets, Plans' Funded Status and Amount Included in Consolidated Balance Sheets	The following tables provide information relating to the accumulated benefit obligation, change in benefit obligation, change in plan assets, the plans’ funded status and the amount included in the consolidated balance sheets for the qualified and non-qualified plans described above (collectively, the Plans): December 31 2017 2016 (in thousands) Accumulated benefit obligation $ 181,412 $ 152,586 Projected benefit obligation at beginning of year $ 152,916 $ 151,015 Acquisition 29,613 — Service cost (13 ) (15 ) Interest cost 6,846 6,129 Actuarial loss 9,061 3,723 Benefits paid (9,728 ) (7,936 ) Settlement (7,158 ) — Projected benefit obligation at end of year $ 181,537 $ 152,916 Fair value of plan assets at beginning of year $ 136,958 $ 132,762 Acquisition 24,961 — Actual return on plan assets 17,327 10,787 Corporation contribution 1,345 1,345 Benefits paid (9,728 ) (7,936 ) Settlement (7,158 ) — Fair value of plan assets at end of year $ 163,705 $ 136,958 Funded status of plans $ (17,832 ) $ (15,958 )
Schedule of Actuarial Assumptions Used in Determination of Projected Benefit Obligation	Actuarial assumptions used in the determination of the projected benefit obligation in the Plans are as follows: Assumptions at December 31 2017 2016 Weighted average discount rate 3.53 % 3.96 % Rates of average increase in compensation levels 3.50 3.50
Schedule of Net Periodic Pension Cost and Other Comprehensive Income	The net periodic pension cost and other comprehensive income for the Plans included the following components: Year Ended December 31 2017 2016 2015 (in thousands) Service cost $ (13 ) $ (15 ) $ (14 ) Interest cost 6,846 6,129 5,897 Expected return on plan assets (11,121 ) (9,413 ) (9,964 ) Transition amount amortization — — — Prior service credit amortization 7 7 7 Actuarial loss amortization 2,461 2,383 2,112 Net periodic pension income (1,820 ) (909 ) (1,962 ) Settlement charge 168 — — Total pension income (1,652 ) (909 ) (1,962 ) Other changes in plan assets and benefit obligations recognized in other comprehensive income: Current year actuarial loss 2,855 2,349 6,914 Amortization of actuarial loss (2,461 ) (2,383 ) (2,112 ) Amortization of prior service credit (7 ) (7 ) (7 ) Amortization of transition asset — — — Total amount recognized in other comprehensive income 387 (41 ) 4,795 Total amount recognized in net periodic benefit cost and other comprehensive income $ (1,265 ) $ (950 ) $ 2,833
Schedule of Actuarial Assumptions Used in Determination of Net Periodic Pension Cost	The plans have an actuarial measurement date of December 31. Actuarial assumptions used in the determination of the net periodic pension cost in the Plans are as follows: Assumptions for the Year Ended December 31 2017 2016 2015 Weighted average discount rate 3.96 % 4.19 % 3.85 % Rates of increase in compensation levels 3.50 3.50 3.50 Expected long-term rate of return on assets 7.25 7.25 7.25
Schedule of Projected Benefit Obligation, Accumulated Benefit Obligation and Fair Value of Plan Assets for Qualified and Non-Qualified Pension Plans	As of December 31, 2017 and 2016 , the projected benefit obligation, accumulated benefit obligation and fair value of plan assets for the qualified and non-qualified pension plans were as follows: (in thousands) Qualified Pension Plans Non-Qualified Pension Plans December 31 2017 2016 2017 2016 Projected benefit obligation $ 161,632 $ 132,902 $ 19,905 $ 20,014 Accumulated benefit obligation 161,632 132,902 19,780 19,684 Fair value of plan assets 163,705 136,958 — —
Schedule of Impact of Changes in Discount Rate, Return on Plan Assets on Pension Expense	The impact of changes in the discount rate and expected long-term rate of return on plan assets would have had the following effects on 2017 pension expense: (in thousands) Estimated Effect on Pension Expense 0.5% decrease in the discount rate $ (97 ) 0.5% decrease in the expected long-term rate of return on plan assets 767
Schedule of Estimated Future Cash Flows	The following table provides information regarding estimated future cash flows relating to the Plans at December 31, 2017 (in thousands): Expected employer contributions: 2018 $ 1,424 Expected benefit payments: 2018 9,474 2019 9,957 2020 10,227 2021 10,390 2022 10,501 2023 – 2027 53,902
Schedule of Contribution Expense	Our contribution expense is presented in the following table: Year Ended December 31 2017 2016 2015 (in thousands) 401(k) contribution expense $ 12,286 $ 9,069 $ 8,055
Schedule of Asset Allocations for Pension Plans	The following table presents asset allocations for our pension plans as of December 31, 2017 and 2016 , and the target allocation for 2018 , by asset category: Target Allocation Percentage of Plan Assets December 31 2018 2017 2016 Asset Category Equity securities 45 - 65 64 % 61 % Debt securities 30 - 50 33 35 Cash equivalents 0 - 10 3 4
Schedule of Fair Values of Pension Plan Assets by Asset Category	The fair values of our pension plan assets by asset category are as follows: (in thousands) Level 1 Level 2 Level 3 Total December 31, 2017 Asset Class Cash $ 5,613 $ — $ — $ 5,613 Equity securities: F.N.B. Corporation 7,948 — — 7,948 Other large-cap U.S. financial services companies 4,269 — — 4,269 Other large-cap U.S. companies 45,583 — — 45,583 International companies 576 — — 576 Other equity 726 — — 726 Mutual fund equity investments: U.S. equity index funds: U.S. large-cap equity index funds 3,489 — — 3,489 U.S. small-cap equity index funds 3,983 — — 3,983 U.S. mid-cap equity index funds 4,836 — — 4,836 Non-U.S. equities growth fund 13,965 — — 13,965 U.S. equity funds: U.S. mid-cap 9,413 — — 9,413 U.S. small-cap 3,165 — — 3,165 Other 5,681 — — 5,681 Fixed income securities: U.S. Treasury bonds — 121 — 121 U.S. government agencies — 37,671 — 37,671 Corporate bonds — 5,532 — 5,532 Fixed income mutual funds: U.S. investment-grade fixed income securities 11,134 — — 11,134 Non-U.S. fixed income securities — — — — Total $ 120,381 $ 43,324 $ — $ 163,705 (in thousands) Level 1 Level 2 Level 3 Total December 31, 2016 Asset Class Cash $ 5,125 $ — $ — $ 5,125 Equity securities: F.N.B. Corporation 9,219 — — 9,219 Other large-cap U.S. financial services companies 2,999 — — 2,999 Other large-cap U.S. companies 36,570 — — 36,570 International companies 718 — — 718 Other equity 596 — — 596 Mutual fund equity investments: U.S. equity index funds: U.S. large-cap equity index funds 559 — — 559 U.S. small-cap equity index funds 3,035 — — 3,035 U.S. mid-cap equity index funds 3,795 — — 3,795 Non-U.S. equities growth fund 9,555 — — 9,555 U.S. equity funds: U.S. mid-cap 7,615 — — 7,615 U.S. small-cap 3,173 — — 3,173 Other 5,928 — — 5,928 Fixed income securities: U.S. government agencies — 36,891 — 36,891 Fixed income mutual funds: U.S. investment-grade fixed income securities 10,766 — — 10,766 Non-U.S. fixed income securities 414 — — 414 Total $ 100,067 $ 36,891 $ — $ 136,958

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Summary of Income Tax Expense Allocated Based on Separate Tax Return Basis	Federal and state income tax expense consist of the following: Year Ended December 31 2017 2016 2015 (in thousands) Current income taxes: Federal taxes $ 26,336 $ 57,894 $ 69,572 State taxes 1,746 2,329 989 Total current income taxes 28,082 60,223 70,561 Deferred income taxes: Federal taxes 128,204 14,983 63 State taxes 779 291 (631 ) Total deferred income taxes 128,983 15,274 (568 ) Total income taxes $ 157,065 $ 75,497 $ 69,993
Summary of Reconciliation Between the Statutory Tax Rate and Actual Effective Tax Rate	The following table provides a reconciliation between the statutory tax rate and the actual effective tax rate: Year Ended December 31 2017 2016 2015 Statutory tax rate 35.0 % 35.0 % 35.0 % State taxes, net of federal benefit 0.5 0.7 0.8 Valuation allowance reversal — — (0.8 ) Tax-exempt interest (3.3 ) (2.9 ) (2.2 ) Cash surrender value on BOLI (1.1 ) (1.5 ) (1.3 ) Tax credits (2.6 ) (0.9 ) (1.1 ) Affordable housing cost amortization, net of tax benefits 0.2 — — Tax Cuts and Jobs Act revaluation of net deferred tax assets 15.2 — — Other items 0.2 0.2 0.1 Actual effective tax rate 44.1 % 30.6 % 30.5 %
Income Tax Expense Related to Gains on Sale of Securities	Income tax expense related to gains on the sale of securities is presented in the following table: Year Ended December 31 2017 2016 2015 (in thousands) Income tax expense related to gains on sale of securities $ 2,071 $ 249 $ 288
Summary of Deferred Tax Assets and Liabilities from Tax Effects of Temporary Differences	The following table presents the tax effects of significant temporary differences that give rise to federal and state deferred tax assets and liabilities: December 31 2017 2016 (in thousands) Deferred tax assets: Allowance for credit losses $ 38,933 $ 56,090 Discounts on acquired loans 64,341 48,978 Net operating loss/tax credit carryforwards 47,376 17,753 Deferred compensation 8,534 12,236 Securities impairments 1,092 — Pension and other defined benefit plans 6,768 7,713 Net unrealized securities losses 7,238 6,972 Other 7,787 11,264 Total 182,069 161,006 Valuation allowance (26,620 ) (18,945 ) Total deferred tax assets 155,449 142,061 Deferred tax liabilities: Loan costs (7,211 ) (2,222 ) Depreciation (12,263 ) (12,392 ) Prepaid expenses (3,669 ) (682 ) Amortizable intangibles (18,422 ) (18,506 ) Lease financing (10,035 ) (5,538 ) Debt discharge income deferral (474 ) (1,361 ) Originated mortgage servicing rights (6,178 ) (748 ) Net unrealized securities gains — (86 ) Other (1,647 ) (1,253 ) Total deferred tax liabilities (59,899 ) (42,788 ) Net deferred tax assets $ 95,550 $ 99,273
Summary of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits (excluding interest and the federal income tax benefit of unrecognized state tax benefits) is as follows: Year Ended December 31 2017 2016 (in thousands) Balance at beginning of year $ 542 $ 455 Additions based on tax positions related to current year 186 163 Additions based on tax positions of prior year — — Reductions for tax positions of prior years (5 ) — Reductions due to expiration of statute of limitations (73 ) (76 ) Balance at end of year $ 650 $ 542

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Changes in AOCI, net of tax, by component	The following table presents changes in AOCI, net of tax, by component: (in thousands) Unrealized Net Gains (Losses) on Securities Available for Sale Unrealized Net Gains (Losses) on Derivative Instruments Unrecognized Pension and Postretirement Obligations Total Year Ended December 31, 2017 Balance at beginning of period $ (18,222 ) $ 5,254 $ (48,401 ) $ (61,369 ) Other comprehensive income (loss) before reclassifications (5,744 ) (759 ) (7 ) (6,510 ) Amounts reclassified from AOCI (411 ) (46 ) — (457 ) Amounts reclassified from AOCI due to tax reform (5,249 ) 958 (10,425 ) (14,716 ) Net current period other comprehensive income (loss) (11,404 ) 153 (10,432 ) (21,683 ) Balance at end of period $ (29,626 ) $ 5,407 $ (58,833 ) $ (83,052 )

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Common Share	The following table sets forth the computation of basic and diluted earnings per common share: Year Ended December 31 2017 2016 2015 (dollars in thousands, except per share data) Net income $ 199,204 $ 170,891 $ 159,649 Less: Preferred stock dividends 8,041 8,041 8,041 Net income available to common stockholders $ 191,163 $ 162,850 $ 151,608 Basic weighted average common shares outstanding 302,195,295 206,244,498 174,971,785 Net effect of dilutive stock options, warrants and restricted stock 1,662,681 1,524,111 1,367,168 Diluted weighted average common shares outstanding 303,857,976 207,768,609 176,338,953 Earnings per common share: Basic $ 0.63 $ 0.79 $ 0.87 Diluted $ 0.63 $ 0.78 $ 0.86
Schedule of Average Shares Excluded from Diluted Earnings Per Common Share Calculation	The following table shows the average shares excluded from the above calculation as their effect would have been anti-dilutive: Year Ended December 31 2017 2016 2015 Average shares excluded from the diluted earnings per common share calculation 910 9,980 18,167

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2017
Banking and Thrift [Abstract]
Schedule of Capital Ratios	Following are the capital ratios for FNB and FNBPA: Actual Well-Capitalized Requirements Minimum Capital Requirements (dollars in thousands) Amount Ratio Amount Ratio Amount Ratio As of December 31, 2017 F.N.B. Corporation: Total capital $ 2,666,272 11.4 % $ 2,340,362 10.0 % $ 2,164,835 9.3 % Tier 1 capital 2,184,571 9.3 1,872,290 8.0 1,696,763 7.3 Common equity tier 1 2,077,689 8.9 1,521,235 6.5 1,345,708 5.8 Leverage 2,184,571 7.6 1,440,797 5.0 1,152,638 4.0 Risk-weighted assets 23,403,622 FNBPA: Total capital 2,504,191 10.7 2,332,593 10.0 2,157,649 9.3 Tier 1 capital 2,332,892 10.0 1,866,075 8.0 1,691,130 7.3 Common equity tier 1 2,252,892 9.7 1,516,186 6.5 1,341,241 5.8 Leverage 2,332,892 8.1 1,432,604 5.0 1,146,084 4.0 Risk-weighted assets 23,325,934 As of December 31, 2016 F.N.B. Corporation: Total capital $ 1,917,386 12.0 % $ 1,597,951 10.0 % $ 1,378,232 8.6 % Tier 1 capital 1,582,251 9.9 1,278,360 8.0 1,058,642 6.6 Common equity tier 1 1,475,369 9.2 1,038,668 6.5 818,950 5.1 Leverage 1,582,251 7.7 1,027,831 5.0 822,265 4.0 Risk-weighted assets 15,979,505 FNBPA: Total capital 1,768,561 11.1 1,588,989 10.0 1,370,503 8.6 Tier 1 capital 1,614,167 10.2 1,271,191 8.0 1,052,705 6.6 Common equity tier 1 1,534,167 9.7 1,032,843 6.5 814,357 5.1 Leverage 1,614,167 7.9 1,019,034 5.0 815,227 4.0 Risk-weighted assets 15,889,893

Cash Flow Information (Tables)

Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Summary of Cash Flow Information	Following is a summary of supplemental cash flow information: Year Ended December 31 2017 2016 2015 (in thousands) Interest paid on deposits and other borrowings $ 129,024 $ 67,296 $ 47,805 Income taxes paid 52,500 60,000 61,500 Transfers of loans to other real estate owned 34,841 14,592 9,628 Financing of other real estate owned sold 19 441 372

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Financial Information for Segments of FNB	The following tables provide financial information for these segments of FNB. The information provided under the caption “Parent and Other” represents operations not considered to be reportable segments and/or general operating expenses of FNB, and includes the parent company, other non-bank subsidiaries and eliminations and adjustments to reconcile to the consolidated financial statements. (in thousands) Community Banking Wealth Manage- ment Insurance Consumer Finance Parent and Other Consolidated At or for the Year Ended December 31, 2017 Interest income $ 943,661 $ — $ 81 $ 40,187 $ (3,603 ) $ 980,326 Interest expense 117,951 — — 3,676 12,265 133,892 Net interest income 825,710 — 81 36,511 (15,868 ) 846,434 Provision for credit losses 52,780 — — 8,293 — 61,073 Non-interest income 197,517 39,256 15,671 3,256 (3,251 ) 252,449 Non-interest expense (1) 596,813 30,563 14,507 21,502 639 664,024 Amortization of intangibles 17,050 254 213 — — 17,517 Income tax expense (benefit) 152,778 2,679 (256 ) 5,283 (3,419 ) 157,065 Net income (loss) 203,806 5,760 1,288 4,689 (16,339 ) 199,204 Total assets 31,155,973 24,218 21,062 181,260 35,122 31,417,635 Total intangibles 2,317,151 10,176 12,127 1,809 — 2,341,263 At or for the Year Ended Interest income $ 640,895 $ — $ 84 $ 40,922 $ (2,938 ) $ 678,963 Interest expense 56,182 — — 3,759 7,510 67,451 Net interest income 584,713 — 84 37,163 (10,448 ) 611,512 Provision for credit losses 49,046 — — 6,706 — 55,752 Non-interest income 149,408 35,283 14,750 3,002 (682 ) 201,761 Non-interest expense (1) 437,031 27,201 12,965 21,662 1,064 499,923 Amortization of intangibles 10,526 259 425 — — 11,210 Income tax expense (benefit) 72,619 2,845 532 4,488 (4,987 ) 75,497 Net income (loss) 164,899 4,978 912 7,309 (7,207 ) 170,891 Total assets 21,629,374 19,619 22,053 193,349 (19,578 ) 21,844,817 Total intangibles 1,061,597 10,189 12,340 1,809 — 1,085,935 At or for the Year Ended Interest income $ 509,585 $ — $ 89 $ 39,868 $ (2,747 ) $ 546,795 Interest expense 41,227 — — 3,518 3,828 48,573 Net interest income 468,358 — 89 36,350 (6,575 ) 498,222 Provision for credit losses 33,045 — — 7,396 — 40,441 Non-interest income 114,377 35,246 13,052 2,926 (3,191 ) 162,410 Non-interest expense (1) 320,912 27,264 13,891 20,189 (12 ) 382,244 Amortization of intangibles 7,544 273 488 — — 8,305 Income tax expense (benefit) 66,979 2,803 (412 ) 4,709 (4,086 ) 69,993 Net income (loss) 154,255 4,906 (826 ) 6,982 (5,668 ) 159,649 Total assets 17,349,459 20,753 22,207 195,048 (29,805 ) 17,557,662 Total intangibles 844,630 10,447 12,923 1,809 — 869,809 (1) Excludes amortization of intangibles, which is presented separately.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Balances of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents the balances of assets and liabilities measured at fair value on a recurring basis: (in thousands) Level 1 Level 2 Level 3 Total December 31, 2017 Assets Measured at Fair Value Debt securities available for sale U.S. Treasury $ — $ — $ — $ — U.S. government-sponsored entities — 343,942 — 343,942 Residential mortgage-backed securities Agency mortgage-backed securities — 1,598,874 — 1,598,874 Agency collateralized mortgage obligations — 794,957 — 794,957 Non-agency collateralized mortgage obligations — 1 — 1 Commercial mortgage-backed securities — — — — States of the U.S. and political subdivisions — 21,093 — 21,093 Other debt securities — 4,670 — 4,670 Total debt securities available for sale — 2,763,537 — 2,763,537 Equity securities available for sale Fixed income mutual fund 161 — — 161 Financial services industry — 864 — 864 Insurance services industry — — — — Total equity securities available for sale 161 864 — 1,025 Total securities available for sale 161 2,764,401 — 2,764,562 Loans held for sale — 56,458 — 56,458 Derivative financial instruments Trading — 28,453 — 28,453 Not for trading — 500 1,594 2,094 Total derivative financial instruments — 28,953 1,594 30,547 Total assets measured at fair value on a recurring basis $ 161 $ 2,849,812 $ 1,594 $ 2,851,567 Liabilities Measured at Fair Value Derivative financial instruments Trading $ — $ 26,953 $ — $ 26,953 Not for trading — 2,239 5 2,244 Total derivative financial instruments — 29,192 5 29,197 Total liabilities measured at fair value on a recurring basis $ — $ 29,192 $ 5 $ 29,197 (in thousands) Level 1 Level 2 Level 3 Total December 31, 2016 Assets Measured at Fair Value Debt securities available for sale U.S. Treasury $ — $ 29,953 $ — $ 29,953 U.S. government-sponsored entities — 365,098 — 365,098 Residential mortgage-backed securities Agency mortgage-backed securities — 1,252,798 — 1,252,798 Agency collateralized mortgage obligations — 535,974 — 535,974 Non-agency collateralized mortgage obligations — 3 894 897 Commercial mortgage-backed securities — 1,291 — 1,291 States of the U.S. and political subdivisions — 35,849 — 35,849 Other debt securities — 9,487 — 9,487 Total debt securities available for sale — 2,230,453 894 2,231,347 Equity securities available for sale Financial services industry — — 492 492 Insurance services industry 148 — — 148 Total equity securities available for sale 148 — 492 640 Total securities available for sale 148 2,230,453 1,386 2,231,987 Derivative financial instruments Trading — 44,951 — 44,951 Not for trading — 9,269 — 9,269 Total derivative financial instruments — 54,220 — 54,220 Total assets measured at fair value on a recurring basis $ 148 $ 2,284,673 $ 1,386 $ 2,286,207 Liabilities Measured at Fair Value Derivative financial instruments Trading $ — $ 45,973 $ — $ 45,973 Not for trading — 1,294 — 1,294 Total derivative financial instruments — 47,267 — 47,267 Total liabilities measured at fair value on a recurring basis $ — $ 47,267 $ — $ 47,267
Additional Information about Assets Measured at Fair Value on Recurring Basis	The following table presents additional information about assets measured at fair value on a recurring basis and for which we have utilized Level 3 inputs to determine fair value: (in thousands) Other Equity Securities Residential Non-Agency Collateralized Mortgage Obligations Interest Total Year Ended December 31, 2017 Balance at beginning of period $ — $ 492 $ 894 $ — $ 1,386 Total gains (losses) – realized/unrealized: Included in earnings — — 4 — 4 Included in other comprehensive income — 86 (6 ) — 80 Accretion included in earnings (1 ) — 1 — — Purchases, issuances, sales and settlements: Purchases 12,048 — — 1,594 13,642 Issuances — — — — — Sales/redemptions (12,047 ) — (874 ) — (12,921 ) Settlements — — (19 ) (4,569 ) (4,588 ) Transfers from Level 3 — (578 ) — — (578 ) Transfers into Level 3 — — — 4,569 4,569 Balance at end of period $ — $ — $ — $ 1,594 $ 1,594 Year Ended December 31, 2016 Balance at beginning of period $ — $ 439 $ 1,184 $ — $ 1,623 Total gains (losses) – realized/unrealized: Included in earnings — — — — — Included in other comprehensive income — 53 (7 ) — 46 Accretion included in earnings — — 6 — 6 Purchases, issuances, sales and settlements: Purchases — — — — — Issuances — — — — — Sales/redemptions — — — — — Settlements — — (289 ) — (289 ) Transfers from Level 3 — — — — — Transfers into Level 3 — — — — — Balance at end of period $ — $ 492 $ 894 $ — $ 1,386
Additional Information about Assets Measured at Fair Value on Non-Recurring Basis	For assets measured at fair value on a non-recurring basis still held at the balance sheet date, the following table provides the hierarchy level and the fair value of the related assets or portfolios: (in thousands) Level 1 Level 2 Level 3 Total December 31, 2017 Impaired loans $ — $ 2,813 $ 1,297 $ 4,110 Other real estate owned — 10,513 10,823 21,336 Loans held for sale - SBA — — 36,432 36,432 Other assets - SBA servicing asset — — 5,058 5,058 December 31, 2016 Impaired loans $ — $ 500 $ 5,883 $ 6,383 Other real estate owned — 11,017 3,181 14,198
Fair Values of Financial Instruments	The fair values of our financial instruments are as follows: Fair Value Measurements (in thousands) Carrying Amount Fair Value Level 1 Level 2 Level 3 December 31, 2017 Financial Assets Cash and cash equivalents $ 479,443 $ 479,443 $ 479,443 $ — $ — Securities available for sale 2,764,562 2,764,562 161 2,764,401 — Securities held to maturity 3,242,268 3,218,379 — 3,218,379 — Net loans and leases, including loans held for sale 20,916,277 20,661,196 — 56,458 20,604,738 Loan servicing rights 34,111 37,758 — — 37,758 Derivative assets 30,547 30,547 — 28,953 1,594 Accrued interest receivable 94,254 94,254 94,254 — — Financial Liabilities Deposits 22,399,725 22,359,182 17,779,246 4,579,936 — Short-term borrowings 3,678,337 3,678,723 3,678,723 — — Long-term borrowings 668,173 675,489 — — 675,489 Derivative liabilities 29,197 29,197 — 29,192 5 Accrued interest payable 12,480 12,480 12,480 — — December 31, 2016 Financial Assets Cash and cash equivalents $ 371,407 $ 371,407 $ 371,407 $ — $ — Securities available for sale 2,231,987 2,231,987 148 2,230,453 1,386 Securities held to maturity 2,337,342 2,294,777 — 2,293,091 1,686 Net loans and leases, including loans held for sale 14,750,792 14,464,274 — — 14,464,274 Loan servicing rights 13,521 17,546 — — 17,546 Derivative assets 54,220 54,220 — 54,220 — Accrued interest receivable 58,712 58,712 58,712 — — Financial Liabilities Deposits 16,065,647 16,045,323 13,489,152 2,556,171 — Short-term borrowings 2,503,010 2,503,277 2,503,277 — — Long-term borrowings 539,494 536,088 — — 536,088 Derivative liabilities 47,267 47,267 — 47,267 — Accrued interest payable 7,612 7,612 7,612 — —

Parent Company Financial Stat59

Parent Company Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Consolidated Balance Sheet of Parent Company Only	Balance Sheets (in thousands) December 31 2017 2016 Assets Cash and cash equivalents $ 165,698 $ 164,276 Securities available for sale 864 492 Other assets 22,344 17,405 Investment in bank subsidiary 4,553,703 2,598,520 Investments in and advances to non-bank subsidiaries 294,236 269,998 Total Assets $ 5,036,845 $ 3,050,691 Liabilities Other liabilities $ 33,000 $ 26,063 Advances from affiliates 306,096 295,897 Long-term borrowings 279,536 147,916 Subordinated notes: Short-term 7,993 8,172 Long-term 1,026 1,026 Total Liabilities 627,651 479,074 Stockholders’ Equity 4,409,194 2,571,617 Total Liabilities and Stockholders’ Equity $ 5,036,845 $ 3,050,691
Statements of Income of Parent Company Only	Statements of Income (in thousands) Year Ended December 31 2017 2016 2015 Income Dividend income from subsidiaries: Bank $ 149,000 $ 108,954 $ 87,580 Non-bank 9,210 8,525 7,863 158,210 117,479 95,443 Interest income 5,323 5,041 4,845 Other income 100 2,799 1,053 Total Income 163,633 125,319 101,341 Expenses Interest expense 17,977 13,609 9,526 Other expenses 10,320 10,377 8,993 Total Expenses 28,297 23,986 18,519 Income Before Taxes and Equity in Undistributed Income of Subsidiaries 135,336 101,333 82,822 Income tax benefit 2,737 6,352 5,088 138,073 107,685 87,910 Equity in undistributed income (loss) of subsidiaries: Bank 60,567 60,924 71,581 Non-bank 564 2,282 158 Net Income $ 199,204 $ 170,891 $ 159,649
Statements of Cash Flows of Parent Company Only	Statements of Cash Flows (in thousands) Year Ended December 31 2017 2016 2015 Operating Activities Net income $ 199,204 $ 170,891 $ 159,649 Adjustments to reconcile net income to net cash flows from operating activities: Undistributed earnings from subsidiaries (61,131 ) (63,206 ) (71,739 ) Other, net 5,441 (2,530 ) 680 Net cash flows provided by operating activities 143,514 105,155 88,590 Investing Activities Proceeds from sale of securities available for sale — 815 — Net (increase) decrease in advances to subsidiaries (9,838 ) (6,263 ) 3,285 Payment for further investment in subsidiaries (4,841 ) (71,050 ) (9,060 ) Net cash received in business combinations 3,173 1,089 — Net cash flows (used in) provided by investing activities (11,506 ) (75,409 ) (5,775 ) Financing Activities Net decrease in advance from affiliate 10,018 6,356 (2,797 ) Net decrease in short-term borrowings (179 ) (44 ) (135 ) Decrease in long-term debt (1,510 ) (10,291 ) (650 ) Increase in long-term debt 563 381 98,794 Net proceeds from issuance of common stock 11,181 18,472 12,731 Tax benefit of stock-based compensation — 1,813 28 Cash dividends paid: Preferred stock (8,041 ) (8,041 ) (8,041 ) Common stock (142,618 ) (101,670 ) (84,511 ) Net cash flows (used in) provided by financing activities (130,586 ) (93,024 ) 15,419 Net (Decrease) Increase in Cash and Cash Equivalents 1,422 (63,278 ) 98,234 Cash and cash equivalents at beginning of year 164,276 227,554 129,320 Cash and Cash Equivalents at End of Year $ 165,698 $ 164,276 $ 227,554 Cash paid during the year for: Interest $ 15,807 $ 13,620 $ 8,309

Quarterly Earnings Summary (U60

Quarterly Earnings Summary (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Earnings Summary (Unaudited) [Abstract]
Quarterly Financial Information	Dollars in thousands, except per share data Quarter Ended 2017 Dec. 31 Sept. 30 June 30 Mar. 31 Total interest income $ 271,085 $ 263,514 $ 251,034 $ 194,693 Total interest expense 41,049 38,283 32,619 21,941 Net interest income 230,036 225,231 218,415 172,752 Provision for credit losses 16,699 16,768 16,756 10,850 Net securities gains 21 2,777 493 2,625 Other non-interest income 65,083 63,374 65,585 52,491 Total non-interest expense 166,529 163,743 163,714 187,555 Net income 24,126 77,693 74,406 22,979 Net income available to common stockholders 22,115 75,683 72,396 20,969 Per Common Share Basic earnings per share $ 0.07 $ 0.23 $ 0.22 $ 0.09 Diluted earnings per share 0.07 0.23 0.22 0.09 Cash dividends declared 0.12 0.12 0.12 0.12 Quarter Ended 2016 Dec. 31 Sept. 30 June 30 Mar. 31 Total interest income $ 177,168 $ 175,110 $ 170,931 $ 155,754 Total interest expense 17,885 17,604 16,562 15,400 Net interest income 159,283 157,506 154,369 140,354 Provision for credit losses 12,705 14,639 16,640 11,768 Net securities gains 116 299 226 71 Other non-interest income 50,950 52,941 51,185 45,973 Total non-interest expense 123,806 121,050 129,629 136,648 Net income 51,291 52,168 41,300 26,132 Net income available to common stockholders 49,280 50,158 39,290 24,122 Per Common Share Basic earnings per share $ 0.23 $ 0.24 $ 0.19 $ 0.12 Diluted earnings per share 0.23 0.24 0.19 0.12 Cash dividends declared 0.12 0.12 0.12 0.12

Nature of Operations (Additiona

Nature of Operations (Additional Information) (Detail)	12 Months Ended
	Dec. 31, 2017OfficeState
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of states, company operating financial services | State	8
Number of banking offices	417
Number of consumer finance offices	77

Summary of Significant Accoun62

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Minimum corporation reserves for commercial loan	$ 500	$ 500
Core deposit intangibles amortization period, years	10 years
Qualified affordable housing project investments	$ 20,900	14,000
Qualified affordable housing project investments, unfunded commitments	$ 67,200	$ 9,800
Largest amount recognized in the financial statement of tax benefit threshold, minimum	Greater than 50%
Total commercial loans
Summary Of Significant Accounting Policies [Line Items]
Number of days placed on non-accrual	90 days	90 days
Installment Loans
Summary Of Significant Accounting Policies [Line Items]
Number of days placed on non-accrual	120 days	120 days
Residential Mortgages
Summary Of Significant Accounting Policies [Line Items]
Number of days placed on non-accrual	180 days	180 days
Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life of the asset, years	3 years
Estimated useful life of intangibles, years	8 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life of the asset, years	40 years
Estimated useful life of intangibles, years	13 years

New Accounting Standards (Detai

New Accounting Standards (Details) $ in Millions	3 Months Ended
	Dec. 31, 2017USD ($)
Accounting Changes and Error Corrections [Abstract]
Reclassification due to tax reform	$ 14.7

Mergers and Acquisitions - Addi

Mergers and Acquisitions - Additional Information (Detail) $ / shares in Units, $ in Thousands	Mar. 11, 2017USD ($)$ / sharesshares	Apr. 22, 2016USD ($)Branch	Feb. 13, 2016USD ($)shares	Sep. 18, 2015USD ($)Branch	Jul. 18, 2015USD ($)	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Business Acquisition [Line Items]
Goodwill recorded as a result of merger						$ 2,249,188	$ 1,032,129	$ 833,086
Merger-related expenses						$ 56,513	37,439	$ 3,033
Pittsburgh
Business Acquisition [Line Items]
Goodwill recorded as a result of merger					$ 1,800
Payments to acquire businesses, cash paid					3,400
Other intangibles recorded as a result of merger					1,400
Other assets recorded as a result of merger					$ 200
Warrant Expires in 2019
Business Acquisition [Line Items]
Warrant issued, exercise price (in usd per share) | $ / shares						$ 11.52
Yadkin Financial Corporation (YDKN)
Business Acquisition [Line Items]
Assets acquired as a result of merger	$ 6,782,439
Loans acquired as a result of merger	5,114,355
Deposits acquired as a result of merger	5,176,915
Value of acquisition	$ 1,784,783
Common stock closing price (in usd per share) | $ / shares	$ 15.97
Common shares issued (in shares) | shares	111,619,622
Common shares to be acquired, shares (in shares) | shares	51,677,565
Number of shares entitled to receive as per merger agreement, Ratio	2.16
Warrant issued, shares (in shares) | shares	207,320
Warrant issued, exercise price (in usd per share) | $ / shares						$ 9.50
Goodwill recorded as a result of merger	$ 1,216,908
Core deposit intangibles recorded as result of the acquisition	55,700
Merger-related expenses						$ 56,200
Percentage of contract termination cost						30.90%
Issuance costs incurred in connection with acquisition						$ 600
Cash acquired as a result of merger	$ 196,964
Yadkin Financial Corporation (YDKN) | Merger - Related Expenses
Business Acquisition [Line Items]
Severance costs						24.30%
Yadkin Financial Corporation (YDKN) | Warrant Expires in 2019
Business Acquisition [Line Items]
Warrant issued, shares (in shares) | shares	207,320					210,135
Warrant issued, exercise price (in usd per share) | $ / shares	$ 9.63
Fifth Third Bank Branches
Business Acquisition [Line Items]
Assets acquired as a result of merger		$ 312,424
Loans acquired as a result of merger		95,354
Deposits acquired as a result of merger		302,529
Value of acquisition		0
Goodwill recorded as a result of merger		14,146
Core deposit intangibles recorded as result of the acquisition		$ 4,100
Number of branch-banking locations acquired | Branch		17
Cash acquired as a result of merger		$ 198,872
Fixed and other assets acquired as a result of merger		$ 14,100
Percentage of deposit premium paid		1.97%
Metro Bancorp Inc
Business Acquisition [Line Items]
Assets acquired as a result of merger			$ 2,783,665
Loans acquired as a result of merger			1,862,447
Deposits acquired as a result of merger			2,328,238
Value of acquisition			$ 404,242
Common shares issued (in shares) | shares			34,041,181
Goodwill recorded as a result of merger			$ 185,054
Core deposit intangibles recorded as result of the acquisition			24,200
Merger-related expenses						$ 400	$ 31,000
Issuance costs incurred in connection with acquisition						$ 700
Cash acquired as a result of merger			$ 46,890
Common shares acquired | shares			14,345,319
Metro Bancorp Inc | Merger - Related Expenses
Business Acquisition [Line Items]
Severance costs						39.90%
Bank of America Branches
Business Acquisition [Line Items]
Assets acquired as a result of merger				$ 153,134
Loans acquired as a result of merger				842
Deposits acquired as a result of merger				154,619
Value of acquisition				0
Goodwill recorded as a result of merger				1,485
Core deposit intangibles recorded as result of the acquisition				$ 3,000
Number of branch-banking locations acquired | Branch				5
Cash acquired as a result of merger				$ 148,159
Fixed and other assets acquired as a result of merger				$ 2,000
Percentage of deposit premium paid				1.96%

Mergers and Acquisitions - Meas

Mergers and Acquisitions - Measurement Period Adjustments (Detail) - Yadkin Financial Corporation (YDKN) $ in Thousands	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Loans and leases	$ 5,114,355
Premises and equipment	70,031
Deferred taxes	125,100
Other liabilities	68,264
Provisional Estimate
Business Acquisition [Line Items]
Loans and leases	5,116,497
Premises and equipment	95,208
Deferred taxes	94,307
Other liabilities	70,761
Increase (Decrease)
Business Acquisition [Line Items]
Loans and leases	(2,142)
Premises and equipment	(25,177)
Deferred taxes	30,793
Other liabilities	$ (2,497)

Mergers and Acquisitions - Pro

Mergers and Acquisitions - Pro Forma Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition Pro Forma Information [Line Items]
Revenue (net interest income and non-interest income)	$ 1,155,977	$ 1,101,638
Net income	248,748	218,197
Net income available to common stockholders	$ 240,707	$ 210,156
Earnings per common share - basic (in USD per share)	$ 0.80	$ 0.67
Earnings per common share - diluted (in USD per share)	$ 0.79	$ 0.67
Proforma Adjustments [Member]
Business Acquisition Pro Forma Information [Line Items]
Revenue (net interest income and non-interest income)	$ 3,419	$ (5,290)
Net income	(1,165)	(7,862)
Net income available to common stockholders	$ (1,165)	$ (7,862)
Earnings per common share - basic (in USD per share)	$ 0	$ 0
Earnings per common share - diluted (in USD per share)	$ 0	$ 0
Yadkin Financial Corporation (YDKN)
Business Acquisition Pro Forma Information [Line Items]
Revenue (net interest income and non-interest income)	$ 74,574	$ 293,655
Net income	22,435	55,168
Net income available to common stockholders	$ 22,435	$ 55,168
Earnings per common share - basic (in USD per share)	$ 0.78	$ 1.15
Earnings per common share - diluted (in USD per share)	$ 0.77	$ 1.14
F.N.B. Corporation
Business Acquisition Pro Forma Information [Line Items]
Revenue (net interest income and non-interest income)	$ 1,077,984	$ 813,273
Net income	227,478	170,891
Net income available to common stockholders	$ 219,437	$ 162,850
Earnings per common share - basic (in USD per share)	$ 0.92	$ 0.79
Earnings per common share - diluted (in USD per share)	$ 0.91	$ 0.78

Mergers and Acquisitions - Amou

Mergers and Acquisitions - Amounts Recorded on Consolidated Balance Sheets in Conjunction with Acquisition (Detail) - USD ($) $ in Thousands	Mar. 11, 2017	Apr. 22, 2016	Feb. 13, 2016	Sep. 18, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill recognized					$ 2,249,188	$ 1,032,129	$ 833,086
Yadkin Financial Corporation (YDKN)
Business Acquisition [Line Items]
Fair value of consideration paid	$ 1,784,783
Cash and cash equivalents	196,964
Securities	940,272
Loans	5,114,355
Core deposit and other intangible assets	69,555
Fixed and other assets	461,293
Total identifiable assets acquired	6,782,439
Deposits	5,176,915
Borrowings	969,385
Other liabilities	68,264
Total liabilities assumed	6,214,564
Fair value of net identifiable assets acquired	567,875
Goodwill recognized	$ 1,216,908
Fifth Third Bank Branches
Business Acquisition [Line Items]
Fair value of consideration paid		$ 0
Cash and cash equivalents		198,872
Securities		0
Loans		95,354
Core deposit and other intangible assets		4,129
Fixed and other assets		14,069
Total identifiable assets acquired		312,424
Deposits		302,529
Borrowings		0
Other liabilities		24,041
Total liabilities assumed		326,570
Fair value of net identifiable assets acquired		(14,146)
Goodwill recognized		$ 14,146
Metro Bancorp Inc
Business Acquisition [Line Items]
Fair value of consideration paid			$ 404,242
Cash and cash equivalents			46,890
Securities			722,980
Loans			1,862,447
Core deposit and other intangible assets			24,163
Fixed and other assets			127,185
Total identifiable assets acquired			2,783,665
Deposits			2,328,238
Borrowings			227,539
Other liabilities			8,700
Total liabilities assumed			2,564,477
Fair value of net identifiable assets acquired			219,188
Goodwill recognized			$ 185,054
Bank of America Branches
Business Acquisition [Line Items]
Fair value of consideration paid				$ 0
Cash and cash equivalents				148,159
Securities				0
Loans				842
Core deposit and other intangible assets				3,000
Fixed and other assets				1,133
Total identifiable assets acquired				153,134
Deposits				154,619
Borrowings				0
Other liabilities				0
Total liabilities assumed				154,619
Fair value of net identifiable assets acquired				(1,485)
Goodwill recognized				$ 1,485

Securities - Schedule of Amorti

Securities - Schedule of Amortized Cost and Fair Value of Securities Available for Sale (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,802,621	$ 2,260,021
Gross Unrealized Gains	1,721	4,172
Gross Unrealized Losses	(39,780)	(32,206)
Fair Value	2,764,562	2,231,987
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	29,874
Gross Unrealized Gains	0	79
Gross Unrealized Losses	0	0
Fair Value	0	29,953
U.S. government-sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	347,767	367,604
Gross Unrealized Gains	52	864
Gross Unrealized Losses	(3,877)	(3,370)
Fair Value	343,942	365,098
Agency mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,615,168	1,267,535
Gross Unrealized Gains	1,225	2,257
Gross Unrealized Losses	(17,519)	(16,994)
Fair Value	1,598,874	1,252,798
Agency collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	813,034	546,659
Gross Unrealized Gains	0	419
Gross Unrealized Losses	(18,077)	(11,104)
Fair Value	794,957	535,974
Non-agency collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1	891
Gross Unrealized Gains	0	6
Gross Unrealized Losses	0	0
Fair Value	1	897
Commercial mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	1,292
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Fair Value	0	1,291
States of the U.S. and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,151	36,065
Gross Unrealized Gains	6	86
Gross Unrealized Losses	(64)	(302)
Fair Value	21,093	35,849
Other debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,913	9,828
Gross Unrealized Gains	0	94
Gross Unrealized Losses	(243)	(435)
Fair Value	4,670	9,487
Total debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,802,034	2,259,748
Gross Unrealized Gains	1,283	3,805
Gross Unrealized Losses	(39,780)	(32,206)
Fair Value	2,763,537	2,231,347
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	587	273
Gross Unrealized Gains	438	367
Gross Unrealized Losses	0	0
Fair Value	$ 1,025	$ 640

Securities - Schedule of Amor69

Securities - Schedule of Amortized Cost and Fair Value of Securities Held to Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 3,242,268	$ 2,337,342
Gross Unrealized Gains	17,357	8,226
Gross Unrealized Losses	(41,246)	(50,791)
Fair Value	3,218,379	2,294,777
U.S. Treasury
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	500	500
Gross Unrealized Gains	134	137
Gross Unrealized Losses	0	0
Fair Value	634	637
U.S. government-sponsored entities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	247,310	272,645
Gross Unrealized Gains	93	348
Gross Unrealized Losses	(4,388)	(4,475)
Fair Value	243,015	268,518
Agency mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,219,802	852,215
Gross Unrealized Gains	3,475	5,654
Gross Unrealized Losses	(9,058)	(8,645)
Fair Value	1,214,219	849,224
Agency collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	777,146	743,148
Gross Unrealized Gains	32	447
Gross Unrealized Losses	(20,095)	(17,801)
Fair Value	757,083	725,794
Non-agency collateralized mortgage obligations
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		1,689
Gross Unrealized Gains		3
Gross Unrealized Losses		(6)
Fair Value		1,686
Commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	80,786	49,797
Gross Unrealized Gains	414	181
Gross Unrealized Losses	(575)	(226)
Fair Value	80,625	49,752
States of the U.S. and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	916,724	417,348
Gross Unrealized Gains	13,209	1,456
Gross Unrealized Losses	(7,130)	(19,638)
Fair Value	$ 922,803	$ 399,166

Securities - Additional Informa

Securities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Securities [Line Items]
Net proceeds from sale of securities	$ 786,762,000	$ 615,199,000	$ 33,499,000
Gross realized gain (loss)	3,700,000
Gross gains	4,700,000
Gross losses	1,000,000
Proceeds from sale of HTM securities	57,050,000	0	0
HTM securities sold, carrying value	54,900,000
Realized gain (loss)	2,200,000
Realized gain on sale of HTM securities	2,200,000
Realized loss on sale of HTM securities	$ 4,000
Return on sale of HTM securities, percent	85.00%
OTTI losses on securities	$ 0	$ 0	$ 0
Municipal bond portfolio, value	$ 937,800,000
Percentage of formal credit enhancement insurance of municipalities	62.00%
Municipal Bonds | Weighted Average
Schedule Of Securities [Line Items]
Average holding size of securities in bond portfolio	$ 3,000,000
Municipal Bonds | Credit Concentration Risk | General Obligation Bonds | A Rating | Minimum
Schedule Of Securities [Line Items]
Percentage of portfolio	99.00%
Municipal Bonds | Geographic Concentration Risk | Pennsylvania, Ohio and Maryland
Schedule Of Securities [Line Items]
Percentage of portfolio	65.00%

Securities - Gross Gains and Gr

Securities - Gross Gains and Gross Losses Realized on Sales of Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Gross gains	$ 6,866	$ 713	$ 831
Gross losses	(950)	(1)	(9)
Net gains	$ 5,916	$ 712	$ 822

Securities - Amortized Cost and

Securities - Amortized Cost and Fair Value of Securities, by Contractual Maturities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule Of Securities [Line Items]
Available for sale, due in one year or less, amortized cost	$ 81,819
Available for sale, due from one to five years, amortized cost	278,153
Available for sale, due from five to ten years, amortized cost	10,892
Available for sale, due after ten years, amortized cost	2,967
Available for sale, with contractual maturities, amortized cost	373,831
Total securities available for sale, amortized cost	2,802,621	$ 2,260,021
Available for sale, due in one year or less, fair value	81,594
Available for sale, due from one to five years, fair value	274,516
Available for sale, due from five to ten years, fair value	10,795
Available for sale, due after ten years, fair value	2,800
Available for sale, with contractual maturities, fair value	369,705
Total securities available for sale, fair value	2,764,562	2,231,987
Held to maturity, due in one year or less, amortized cost	30,438
Held to maturity, due from one to five years, amortized cost	225,054
Held to maturity, due from five to ten years, amortized cost	81,650
Held to maturity, due after ten years, amortized cost	827,392
Securities held to maturity, with contractual maturities, amortized cost	1,164,534
Held to maturity, with contractual maturities, amortized cost	3,242,268	2,337,342
Held to maturity, due in one year or less, fair value	30,254
Held to maturity, due from one to five years, fair value	220,921
Held to maturity, due from five to ten years, fair value	82,672
Held to maturity, due after ten years, fair value	832,605
Securities held to maturity, with contractual maturities, fair value	1,166,452
Held to maturity, with contractual maturities, fair value	3,218,379	2,294,777
Agency mortgage-backed securities
Schedule Of Securities [Line Items]
Total securities available for sale, amortized cost	1,615,168	1,267,535
Total securities available for sale, fair value	1,598,874	1,252,798
Held to maturity, with contractual maturities, amortized cost	1,219,802
Held to maturity, with contractual maturities, fair value	1,214,219
Agency collateralized mortgage obligations
Schedule Of Securities [Line Items]
Total securities available for sale, amortized cost	813,034	546,659
Total securities available for sale, fair value	794,957	535,974
Held to maturity, with contractual maturities, amortized cost	777,146
Held to maturity, with contractual maturities, fair value	757,083
Non-agency collateralized mortgage obligations
Schedule Of Securities [Line Items]
Total securities available for sale, amortized cost	1	891
Total securities available for sale, fair value	1	897
Held to maturity, with contractual maturities, amortized cost	0
Held to maturity, with contractual maturities, fair value	0
Commercial mortgage-backed securities
Schedule Of Securities [Line Items]
Total securities available for sale, amortized cost	0	1,292
Total securities available for sale, fair value	0	1,291
Held to maturity, with contractual maturities, amortized cost	80,786
Held to maturity, with contractual maturities, fair value	80,625
Equity securities
Schedule Of Securities [Line Items]
Total securities available for sale, amortized cost	587	273
Total securities available for sale, fair value	1,025	$ 640
Held to maturity, with contractual maturities, amortized cost	0
Held to maturity, with contractual maturities, fair value	$ 0

Securities - Schedule of Securi

Securities - Schedule of Securities Pledged as Collateral (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
To secure public deposits, trust deposits and for other purposes as required by law	$ 3,491,634	$ 2,779,335
As collateral for short-term borrowings	$ 263,756	$ 322,038
Securities pledged as a percent of total securities	62.50%	67.90%

Securities - Summaries of Fair

Securities - Summaries of Fair Values and Unrealized Losses of Securities, Segregated by Length of Impairment (Detail) $ in Thousands	Dec. 31, 2017USD ($)Security	Dec. 31, 2016USD ($)Security
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	71	113
Number of available for sale securities, greater than 1 year | Security	75	12
Number of available for sale securities | Security	146	125
Securities available for sale, less than 12 months, fair value	$ 1,503,806	$ 1,644,951
Securities available for sale, less than 12 months, unrealized losses	(14,372)	(27,928)
Securities available for sale, 12 months or more, fair value	1,016,111	93,510
Securities available for sale, 12 months or more, unrealized losses	(25,408)	(4,278)
Securities available for sale, fair value, total	2,519,917	1,738,461
Securities available for sale, unrealized losses, total	$ (39,780)	$ (32,206)
Number of held to maturity securities | Security	168	186
Securities held to maturity, less than 12 months, fair value	$ 1,061,703	$ 1,513,912
Securities held to maturity, less than 12 months, unrealized losses	(7,851)	(46,484)
Securities held to maturity, greater than 12 months, fair value	984,076	120,957
Securities held to maturity, greater than 12 months, unrealized losses	(33,395)	(4,307)
Securities held to maturity, fair value, total	2,045,779	1,634,869
Securities held to maturity, unrealized losses, total	$ 41,246	$ 50,791
Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	73	173
12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	95	13
U.S. government-sponsored entities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	7	11
Number of available for sale securities, greater than 1 year | Security	10	0
Number of available for sale securities | Security	17	11
Securities available for sale, less than 12 months, fair value	$ 106,809	$ 211,636
Securities available for sale, less than 12 months, unrealized losses	(363)	(3,370)
Securities available for sale, 12 months or more, fair value	201,485	0
Securities available for sale, 12 months or more, unrealized losses	(3,514)	0
Securities available for sale, fair value, total	308,294	211,636
Securities available for sale, unrealized losses, total	$ (3,877)	$ (3,370)
Number of held to maturity securities | Security	14	10
Securities held to maturity, less than 12 months, fair value	$ 54,790	$ 185,525
Securities held to maturity, less than 12 months, unrealized losses	(239)	(4,475)
Securities held to maturity, greater than 12 months, fair value	185,851	0
Securities held to maturity, greater than 12 months, unrealized losses	(4,149)	0
Securities held to maturity, fair value, total	240,641	185,525
Securities held to maturity, unrealized losses, total	$ 4,388	$ 4,475
U.S. government-sponsored entities | Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	4	10
U.S. government-sponsored entities | 12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	10	0
Agency mortgage-backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	43	55
Number of available for sale securities, greater than 1 year | Security	28	0
Number of available for sale securities | Security	71	55
Securities available for sale, less than 12 months, fair value	$ 976,738	$ 1,056,731
Securities available for sale, less than 12 months, unrealized losses	(7,723)	(16,994)
Securities available for sale, 12 months or more, fair value	473,625	0
Securities available for sale, 12 months or more, unrealized losses	(9,796)	0
Securities available for sale, fair value, total	1,450,363	1,056,731
Securities available for sale, unrealized losses, total	$ (17,519)	$ (16,994)
Number of held to maturity securities | Security	47	36
Securities held to maturity, less than 12 months, fair value	$ 648,485	$ 551,404
Securities held to maturity, less than 12 months, unrealized losses	(4,855)	(8,645)
Securities held to maturity, greater than 12 months, fair value	183,989	0
Securities held to maturity, greater than 12 months, unrealized losses	(4,203)	0
Securities held to maturity, fair value, total	832,474	551,404
Securities held to maturity, unrealized losses, total	$ 9,058	$ 8,645
Agency mortgage-backed securities | Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	36	36
Agency mortgage-backed securities | 12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	11	0
Agency collateralized mortgage obligations
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	14	26
Number of available for sale securities, greater than 1 year | Security	33	9
Number of available for sale securities | Security	47	35
Securities available for sale, less than 12 months, fair value	$ 409,005	$ 346,662
Securities available for sale, less than 12 months, unrealized losses	(6,231)	(7,261)
Securities available for sale, 12 months or more, fair value	335,452	89,040
Securities available for sale, 12 months or more, unrealized losses	(11,846)	(3,843)
Securities available for sale, fair value, total	744,457	435,702
Securities available for sale, unrealized losses, total	$ (18,077)	$ (11,104)
Number of held to maturity securities | Security	49	41
Securities held to maturity, less than 12 months, fair value	$ 275,290	$ 516,237
Securities held to maturity, less than 12 months, unrealized losses	(1,701)	(13,710)
Securities held to maturity, greater than 12 months, fair value	473,257	112,690
Securities held to maturity, greater than 12 months, unrealized losses	(18,394)	(4,091)
Securities held to maturity, fair value, total	748,547	628,927
Securities held to maturity, unrealized losses, total	$ 20,095	$ 17,801
Agency collateralized mortgage obligations | Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	14	29
Agency collateralized mortgage obligations | 12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	35	12
Non-agency collateralized mortgage obligations
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	0
Number of available for sale securities, greater than 1 year | Security	0
Number of available for sale securities | Security	0
Securities available for sale, less than 12 months, fair value	$ 0
Securities available for sale, less than 12 months, unrealized losses	0
Securities available for sale, 12 months or more, fair value	0
Securities available for sale, 12 months or more, unrealized losses	0
Securities available for sale, fair value, total	0
Securities available for sale, unrealized losses, total	$ 0
Number of held to maturity securities | Security	0	3
Securities held to maturity, less than 12 months, fair value	$ 0	$ 1,128
Securities held to maturity, less than 12 months, unrealized losses	0	(6)
Securities held to maturity, greater than 12 months, fair value	0	0
Securities held to maturity, greater than 12 months, unrealized losses	0	0
Securities held to maturity, fair value, total	0	1,128
Securities held to maturity, unrealized losses, total	$ 0	$ 6
Non-agency collateralized mortgage obligations | Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	0	3
Non-agency collateralized mortgage obligations | 12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	0	0
Commercial mortgage-backed securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	0	1
Number of available for sale securities, greater than 1 year | Security	0	0
Number of available for sale securities | Security	0	1
Securities available for sale, less than 12 months, fair value	$ 0	$ 1,291
Securities available for sale, less than 12 months, unrealized losses	0	(1)
Securities available for sale, 12 months or more, fair value	0	0
Securities available for sale, 12 months or more, unrealized losses	0	0
Securities available for sale, fair value, total	0	1,291
Securities available for sale, unrealized losses, total	$ 0	$ (1)
Number of held to maturity securities | Security	5	2
Securities held to maturity, less than 12 months, fair value	$ 26,399	$ 12,317
Securities held to maturity, less than 12 months, unrealized losses	(123)	(10)
Securities held to maturity, greater than 12 months, fair value	19,443	8,267
Securities held to maturity, greater than 12 months, unrealized losses	(452)	(216)
Securities held to maturity, fair value, total	45,842	20,584
Securities held to maturity, unrealized losses, total	$ 575	$ 226
Commercial mortgage-backed securities | Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	3	1
Commercial mortgage-backed securities | 12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	2	1
States of the U.S. and political subdivisions
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	7	20
Number of available for sale securities, greater than 1 year | Security	1	0
Number of available for sale securities | Security	8	20
Securities available for sale, less than 12 months, fair value	$ 11,254	$ 28,631
Securities available for sale, less than 12 months, unrealized losses	(55)	(302)
Securities available for sale, 12 months or more, fair value	879	0
Securities available for sale, 12 months or more, unrealized losses	(9)	0
Securities available for sale, fair value, total	12,133	28,631
Securities available for sale, unrealized losses, total	$ (64)	$ (302)
Number of held to maturity securities | Security	53	94
Securities held to maturity, less than 12 months, fair value	$ 56,739	$ 247,301
Securities held to maturity, less than 12 months, unrealized losses	(933)	(19,638)
Securities held to maturity, greater than 12 months, fair value	121,536	0
Securities held to maturity, greater than 12 months, unrealized losses	(6,197)	0
Securities held to maturity, fair value, total	178,275	247,301
Securities held to maturity, unrealized losses, total	$ 7,130	$ 19,638
States of the U.S. and political subdivisions | Less than 12 Months
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	16	94
States of the U.S. and political subdivisions | 12 Months or More
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of held to maturity securities | Security	37	0
Other debt securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	0	0
Number of available for sale securities, greater than 1 year | Security	3	3
Number of available for sale securities | Security	3	3
Securities available for sale, less than 12 months, fair value	$ 0	$ 0
Securities available for sale, less than 12 months, unrealized losses	0	0
Securities available for sale, 12 months or more, fair value	4,670	4,470
Securities available for sale, 12 months or more, unrealized losses	(243)	(435)
Securities available for sale, fair value, total	4,670	4,470
Securities available for sale, unrealized losses, total	$ (243)	$ (435)
Equity securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Number of available for sale securities, less than 1 year | Security	0
Number of available for sale securities, greater than 1 year | Security	0
Number of available for sale securities | Security	0
Securities available for sale, less than 12 months, fair value	$ 0
Securities available for sale, less than 12 months, unrealized losses	0
Securities available for sale, 12 months or more, fair value	0
Securities available for sale, 12 months or more, unrealized losses	0
Securities available for sale, fair value, total	0
Securities available for sale, unrealized losses, total	$ 0

Securities - Summary of Cumulat

Securities - Summary of Cumulative Credit-Related OTTI Charges (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance	$ 27
Loss where impairment was not previously recognized	0
Additional loss where impairment was previously recognized	0
Reduction due to credit impaired securities sold	(27)
Ending balance	0
Equity securities
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance	27
Loss where impairment was not previously recognized	0
Additional loss where impairment was previously recognized	0
Reduction due to credit impaired securities sold	(27)
Ending balance	$ 0

Federal Home Loan Bank Stock -

Federal Home Loan Bank Stock - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Banking and Thrift [Abstract]
Federal Home Loan Bank stock	$ 160.5	$ 85

Loans and Leases - Summary of L

Loans and Leases - Summary of Loans and Leases, Net of Unearned Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	$ 20,998,766	$ 14,896,943
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	8,741,864	5,435,162
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	4,170,667	3,042,781
Commercial leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	266,720	196,636
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	17,063	35,878
Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	7,802,452	6,186,486
Total commercial loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	13,196,314	8,710,457
Direct installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,905,535	1,844,399
Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	2,702,691	1,844,574
Indirect installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,448,433	1,196,313
Consumer lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,745,793	1,301,200
Originated Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	15,345,490	12,547,987
Originated Loans and Leases | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	5,174,783	4,095,817
Originated Loans and Leases | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	3,495,247	2,711,886
Originated Loans and Leases | Commercial leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	266,720	196,636
Originated Loans and Leases | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	17,063	35,878
Originated Loans and Leases | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	6,391,677	5,507,770
Originated Loans and Leases | Total commercial loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	8,953,813	7,040,217
Originated Loans and Leases | Direct installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,755,713	1,765,257
Originated Loans and Leases | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	2,036,226	1,446,776
Originated Loans and Leases | Indirect installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,448,268	1,196,110
Originated Loans and Leases | Consumer lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,151,470	1,099,627
Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	5,653,276	2,348,956
Acquired Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	3,567,081	1,339,345
Acquired Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	675,420	330,895
Acquired Loans | Commercial leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	0	0
Acquired Loans | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	0	0
Acquired Loans | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	1,410,775	678,716
Acquired Loans | Total commercial loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	4,242,501	1,670,240
Acquired Loans | Direct installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	149,822	79,142
Acquired Loans | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	666,465	397,798
Acquired Loans | Indirect installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	165	203
Acquired Loans | Consumer lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net of unearned income	$ 594,323	$ 201,573

Loans and Leases - Certain Info

Loans and Leases - Certain Information Relating to Regency Consumer Finance Loans (Detail) - Consumer lines of credit - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Regency consumer finance loans	$ 174,916	$ 184,687
Loan portfolio diversification risk | Loans and leases receivable net of deferred income
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	0.80%	1.20%

Loans and Leases - Certain In79

Loans and Leases - Certain Information Relating to Commercial Real Estate Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Line Items]
Commercial construction, acquisition and development loans	$ 1,170,175	$ 597,617
Credit Concentration Risk | Commercial construction loans
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	5.60%	4.00%
Loan portfolio diversification risk | Commercial real estate loans | Percent owner-occupied
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	35.30%	36.20%
Loan portfolio diversification risk | Commercial real estate loans | Percent non-owner-occupied
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	64.70%	63.80%

Loans and Leases - Summary of80

Loans and Leases - Summary of Loans to Related Parties (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Loans and Leases Receivable, Related Parties [Roll Forward]
Balance at beginning of period	$ 21,569
New loans	1,171
Repayments	(3,447)
Other	(518)
Balance at end of period	$ 19,811

Loans and Leases - Summary of O

Loans and Leases - Summary of Outstanding Principal Balance and Carrying Amount of Acquired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	$ 20,998,766	$ 14,896,943
Accounted for under ASC 310-30:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	5,176,015	2,346,687
Carrying amount	4,834,256	2,015,904
Accounted for under ASC 310-20:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	835,130	342,015
Carrying amount	812,322	325,784
Total acquired loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding balance	6,011,145	2,688,702
Carrying amount	$ 5,646,578	$ 2,341,688

Loans and Leases - Additional I

Loans and Leases - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	$ 20,998,766,000	$ 14,896,943,000
Reclassification from non-accretable difference	155,840,000	$ 92,823,000
Sustained period of delinquency for impairment evaluation		90 days
Minimum reserves for commercial loan	500,000	$ 500,000
Minimum amount to allocate specific valuation allowance		500,000
Interest income on impaired loans still accruing	6,100,000	4,600,000	$ 4,100,000
Restructured loans returned to performing status	3,900,000
Valuation for impairment of loans with pooled reserves	500,000
Pooled reserves for all other classes of loans	4,000,000	3,700,000
Loan Purchased not Subject to ASC 310-30
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans acquired and accounted for under ASC 310-30, Fair value	778,400,000
Loans acquired and accounted for under ASC 310-30, Unpaid principal balance	791,300,000
Loans acquired and accounted for under ASC 310-30, Contractual cash flows not expected to be collected	122,900,000
Purchased credit-impaired loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying amount	$ 1,900,000	$ 2,800,000
Credit Concentration Risk | Acquired Loans Receivable | Purchased credit-impaired loans | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of portfolio	0.03%
Credit Concentration Risk | Acquired Loans Receivable | Purchased credit-impaired loans | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of portfolio		0.12%
Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold period past due for default non-accrual status of trade accounts receivable	90 days	90 days
Installment Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold period past due for default non-accrual status of trade accounts receivable	120 days	120 days
Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold period past due for default non-accrual status of trade accounts receivable	180 days	180 days
Carrying value of OREO through foreclosure	$ 3,600,000
Mortgage loans on real estate, foreclosure	$ 15,200,000	$ 12,000,000

Loans and Leases - Summary of C

Loans and Leases - Summary of Change in Accretable Yield of Acquired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Balance at beginning of period	$ 467,070	$ 256,120
Acquisitions	444,715	308,312
Reduction due to unexpected early payoffs	(127,949)	(86,046)
Reclass from non-accretable difference	155,840	92,823
Disposals/transfers	(3,559)	(409)
Other	(658)	0
Accretion	(226,978)	(103,730)
Balance at end of period	$ 708,481	$ 467,070

Loans and Leases - Summary of A

Loans and Leases - Summary of Acquisition of Purchased Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Accretable yield	$ (226,978)	$ (103,730)
Yadkin Financial Corporation (YDKN)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required cash flows at acquisition	5,131,765
Non-accretable difference (expected losses and foregone interest)	430,097
Cash flows expected to be collected at acquisition	4,701,668
Accretable yield	(444,715)
Fair value of acquired loans at acquisition	4,256,953
Yadkin Financial Corporation (YDKN) | Acquired Impaired Loans
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required cash flows at acquisition	46,053
Non-accretable difference (expected losses and foregone interest)	23,924
Cash flows expected to be collected at acquisition	22,129
Accretable yield	(3,266)
Fair value of acquired loans at acquisition	18,863
Yadkin Financial Corporation (YDKN) | Acquired Performing Loans
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required cash flows at acquisition	5,085,712
Non-accretable difference (expected losses and foregone interest)	406,173
Cash flows expected to be collected at acquisition	4,679,539
Accretable yield	(441,449)
Fair value of acquired loans at acquisition	$ 4,238,090

Loans and Leases - Summary of N

Loans and Leases - Summary of Non-Performing Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings	$ 53,991	$ 46,933
Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	74,635	65,479
Troubled debt restructurings	23,481	20,428
Total non-performing loans	98,116	85,907
Other real estate owned (OREO)	40,606	32,490
Total non-performing assets	$ 138,722	$ 118,397
Non-performing loans / total loans and leases	0.47%	0.58%
Non-performing loans OREO / total loans and leases OREO	0.66%	0.79%
Non-performing assets / total assets	0.44%	0.54%

Loans and Leases - Age Analysis

Loans and Leases - Age Analysis of Past Due Loans, by Class (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	$ 20,998,766	$ 14,896,943
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	8,741,864	5,435,162
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	4,170,667	3,042,781
Commercial leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	266,720	196,636
Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	17,063	35,878
Total commercial loans and leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	13,196,314	8,710,457
Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	1,905,535	1,844,399
Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	2,702,691	1,844,574
Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	1,448,433	1,196,313
Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	1,745,793	1,301,200
Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	7,802,452	6,186,486
Originated Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	63,644	62,083
Total Past Due	134,911	131,046
Current	15,210,579	12,416,941
Total Loans and Leases	15,345,490	12,547,987
Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	24,773	20,114
Total Past Due	33,047	28,567
Current	5,141,736	4,067,250
Total Loans and Leases	5,174,783	4,095,817
Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	17,077	24,141
Total Past Due	26,028	40,163
Current	3,469,219	2,671,723
Total Loans and Leases	3,495,247	2,711,886
Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	1,574	3,429
Total Past Due	2,997	4,403
Current	263,723	192,233
Total Loans and Leases	266,720	196,636
Originated Loans and Leases | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	1,000	1,000
Total Past Due	1,236	1,481
Current	15,827	34,397
Total Loans and Leases	17,063	35,878
Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	44,424	48,684
Total Past Due	63,308	74,614
Current	8,890,505	6,965,603
Total Loans and Leases	8,953,813	7,040,217
Originated Loans and Leases | Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	8,896	6,484
Total Past Due	26,554	21,443
Current	1,729,159	1,743,814
Total Loans and Leases	1,755,713	1,765,257
Originated Loans and Leases | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	5,771	3,316
Total Past Due	22,699	16,924
Current	2,013,527	1,429,852
Total Loans and Leases	2,036,226	1,446,776
Originated Loans and Leases | Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	2,240	1,983
Total Past Due	13,164	11,808
Current	1,435,104	1,184,302
Total Loans and Leases	1,448,268	1,196,110
Originated Loans and Leases | Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	2,313	1,616
Total Past Due	9,186	6,257
Current	1,142,284	1,093,370
Total Loans and Leases	1,151,470	1,099,627
Originated Loans and Leases | Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	19,220	13,399
Total Past Due	71,603	56,432
Current	6,320,074	5,451,338
Total Loans and Leases	6,391,677	5,507,770
Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	10,991	3,396
Total Past Due	167,867	68,130
Current	5,768,610	2,430,340
(Discount)/ Premium	(283,201)	(149,514)
Total Loans and Leases	5,653,276	2,348,956
Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	3,975	949
Total Past Due	101,995	34,340
Current	3,657,152	1,384,752
(Discount)/ Premium	(192,066)	(79,747)
Total Loans and Leases	3,567,081	1,339,345
Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	5,663	2,111
Total Past Due	15,302	6,842
Current	698,265	353,494
(Discount)/ Premium	(38,147)	(29,441)
Total Loans and Leases	675,420	330,895
Acquired Loans | Total commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	9,638	3,060
Total Past Due	117,297	41,182
Current	4,355,417	1,738,246
(Discount)/ Premium	(230,213)	(109,188)
Total Loans and Leases	4,242,501	1,670,240
Acquired Loans | Commercial leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	0	0
Acquired Loans | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	0	0
Acquired Loans | Total commercial loans and leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans and Leases	4,242,501	1,670,240
Acquired Loans | Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	0	0
Total Past Due	7,280	3,661
Current	141,386	73,479
(Discount)/ Premium	1,156	2,002
Total Loans and Leases	149,822	79,142
Acquired Loans | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	0	0
Total Past Due	32,330	19,244
Current	675,499	416,561
(Discount)/ Premium	(41,364)	(38,007)
Total Loans and Leases	666,465	397,798
Acquired Loans | Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	0	0
Total Past Due	1	23
Current	10	96
(Discount)/ Premium	154	84
Total Loans and Leases	165	203
Acquired Loans | Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	1,353	336
Total Past Due	10,959	4,020
Current	596,298	201,958
(Discount)/ Premium	(12,934)	(4,405)
Total Loans and Leases	594,323	201,573
Acquired Loans | Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non- Accrual	1,353	336
Total Past Due	50,570	26,948
Current	1,413,193	692,094
(Discount)/ Premium	(52,988)	(40,326)
Total Loans and Leases	1,410,775	678,716
30-89 Days Past Due | Originated Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	62,146	59,850
30-89 Days Past Due | Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,273	8,452
30-89 Days Past Due | Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,948	16,019
30-89 Days Past Due | Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,382	973
30-89 Days Past Due | Originated Loans and Leases | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	83	398
30-89 Days Past Due | Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18,686	25,842
30-89 Days Past Due | Originated Loans and Leases | Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	13,192	10,573
30-89 Days Past Due | Originated Loans and Leases | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	14,096	10,594
30-89 Days Past Due | Originated Loans and Leases | Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,313	9,312
30-89 Days Past Due | Originated Loans and Leases | Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,859	3,529
30-89 Days Past Due | Originated Loans and Leases | Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	43,460	34,008
30-89 Days Past Due | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	66,926	24,210
30-89 Days Past Due | Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	34,928	9,501
30-89 Days Past Due | Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,187	1,789
30-89 Days Past Due | Acquired Loans | Total commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	38,115	11,290
30-89 Days Past Due | Acquired Loans | Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,267	2,317
30-89 Days Past Due | Acquired Loans | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	17,191	8,428
30-89 Days Past Due | Acquired Loans | Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	19
30-89 Days Past Due | Acquired Loans | Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,353	2,156
30-89 Days Past Due | Acquired Loans | Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	28,811	12,920
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,121	9,113
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1	1
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3	3
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	41	1
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	153	83
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	198	88
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,466	4,386
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,832	3,014
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	611	513
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,014	1,112
≥ 90 Days Past Due and Still Accruing | Originated Loans and Leases | Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,923	9,025
≥ 90 Days Past Due and Still Accruing | Acquired Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	89,950	40,524
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	63,092	23,890
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,452	2,942
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Total commercial loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	69,544	26,832
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Direct installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,013	1,344
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Residential mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	15,139	10,816
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Indirect installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1	4
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Consumer lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,253	1,528
≥ 90 Days Past Due and Still Accruing | Acquired Loans | Total consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 20,406	$ 13,692

Loans and Leases - Summary of87

Loans and Leases - Summary of Commercial Loans and Leases by Credit Quality (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	$ 20,998,766	$ 14,896,943
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	8,741,864	5,435,162
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	4,170,667	3,042,781
Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	266,720	196,636
Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	17,063	35,878
Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	13,196,314	8,710,457
Originated Loans and Leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	15,345,490	12,547,987
Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	5,174,783	4,095,817
Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,495,247	2,711,886
Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	266,720	196,636
Originated Loans and Leases | Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	17,063	35,878
Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	8,953,813	7,040,217
Acquired Loans
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	5,653,276	2,348,956
Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,567,081	1,339,345
Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	675,420	330,895
Acquired Loans | Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	0	0
Acquired Loans | Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	0	0
Acquired Loans | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	4,242,501	1,670,240
Pass | Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	4,922,872	3,895,764
Pass | Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,266,966	2,475,955
Pass | Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	260,235	188,662
Pass | Originated Loans and Leases | Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	15,866	34,531
Pass | Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	8,465,939	6,594,912
Pass | Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,102,788	1,144,676
Pass | Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	603,611	274,819
Pass | Acquired Loans | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,706,399	1,419,495
Special Mention | Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	152,744	130,452
Special Mention | Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	132,975	104,652
Special Mention | Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	4,425	3,789
Special Mention | Originated Loans and Leases | Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	43	264
Special Mention | Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	290,187	239,157
Special Mention | Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	250,987	85,894
Special Mention | Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	26,059	20,593
Special Mention | Acquired Loans | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	277,046	106,487
Substandard | Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	98,728	69,588
Substandard | Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	92,091	128,089
Substandard | Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	2,060	4,185
Substandard | Originated Loans and Leases | Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	1,154	1,083
Substandard | Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	194,033	202,945
Substandard | Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	213,089	108,128
Substandard | Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	45,661	34,967
Substandard | Acquired Loans | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	258,750	143,095
Doubtful | Originated Loans and Leases | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	439	13
Doubtful | Originated Loans and Leases | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,215	3,190
Doubtful | Originated Loans and Leases | Commercial leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	0	0
Doubtful | Originated Loans and Leases | Other
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	0	0
Doubtful | Originated Loans and Leases | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	3,654	3,203
Doubtful | Acquired Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	217	647
Doubtful | Acquired Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	89	516
Doubtful | Acquired Loans | Total commercial loans and leases
Financing Receivable, Recorded Investment [Line Items]
Total commercial loans and leases	$ 306	$ 1,163

Loans and Leases - Summary of88

Loans and Leases - Summary of Consumer Loans by Payment Status (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Credit Quality [Line Items]
Total Loans and Leases	$ 20,998,766	$ 14,896,943
Direct installment
Credit Quality [Line Items]
Total Loans and Leases	1,905,535	1,844,399
Residential mortgages
Credit Quality [Line Items]
Total Loans and Leases	2,702,691	1,844,574
Indirect installment
Credit Quality [Line Items]
Total Loans and Leases	1,448,433	1,196,313
Originated Loans and Leases
Credit Quality [Line Items]
Total Loans and Leases	15,345,490	12,547,987
Originated Loans and Leases | Direct installment
Credit Quality [Line Items]
Total Loans and Leases	1,755,713	1,765,257
Originated Loans and Leases | Residential mortgages
Credit Quality [Line Items]
Total Loans and Leases	2,036,226	1,446,776
Originated Loans and Leases | Indirect installment
Credit Quality [Line Items]
Total Loans and Leases	1,448,268	1,196,110
Acquired Loans
Credit Quality [Line Items]
Total Loans and Leases	5,653,276	2,348,956
Acquired Loans | Direct installment
Credit Quality [Line Items]
Total Loans and Leases	149,822	79,142
Acquired Loans | Residential mortgages
Credit Quality [Line Items]
Total Loans and Leases	666,465	397,798
Acquired Loans | Indirect installment
Credit Quality [Line Items]
Total Loans and Leases	165	203
Total consumer loans | Originated Loans and Leases
Credit Quality [Line Items]
Total Loans and Leases	6,391,677	5,507,770
Total consumer loans | Originated Loans and Leases | Performing
Credit Quality [Line Items]
Total Loans and Leases	6,352,285	5,474,286
Total consumer loans | Originated Loans and Leases | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	39,392	33,484
Total consumer loans | Originated Loans and Leases | Direct installment
Credit Quality [Line Items]
Total Loans and Leases	1,755,713	1,765,257
Total consumer loans | Originated Loans and Leases | Direct installment | Performing
Credit Quality [Line Items]
Total Loans and Leases	1,739,060	1,750,305
Total consumer loans | Originated Loans and Leases | Direct installment | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	16,653	14,952
Total consumer loans | Originated Loans and Leases | Residential mortgages
Credit Quality [Line Items]
Total Loans and Leases	2,036,226	1,446,776
Total consumer loans | Originated Loans and Leases | Residential mortgages | Performing
Credit Quality [Line Items]
Total Loans and Leases	2,019,816	1,433,409
Total consumer loans | Originated Loans and Leases | Residential mortgages | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	16,410	13,367
Total consumer loans | Originated Loans and Leases | Indirect installment
Credit Quality [Line Items]
Total Loans and Leases	1,448,268	1,196,110
Total consumer loans | Originated Loans and Leases | Indirect installment | Performing
Credit Quality [Line Items]
Total Loans and Leases	1,445,833	1,193,930
Total consumer loans | Originated Loans and Leases | Indirect installment | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	2,435	2,180
Total consumer loans | Originated Loans and Leases | Consumer lines of credit
Credit Quality [Line Items]
Total Loans and Leases	1,151,470	1,099,627
Total consumer loans | Originated Loans and Leases | Consumer lines of credit | Performing
Credit Quality [Line Items]
Total Loans and Leases	1,147,576	1,096,642
Total consumer loans | Originated Loans and Leases | Consumer lines of credit | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	3,894	2,985
Total consumer loans | Acquired Loans
Credit Quality [Line Items]
Total Loans and Leases	1,410,775	678,716
Total consumer loans | Acquired Loans | Performing
Credit Quality [Line Items]
Total Loans and Leases	1,408,765	678,204
Total consumer loans | Acquired Loans | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	2,010	512
Total consumer loans | Acquired Loans | Direct installment
Credit Quality [Line Items]
Total Loans and Leases	149,822	79,142
Total consumer loans | Acquired Loans | Direct installment | Performing
Credit Quality [Line Items]
Total Loans and Leases	149,751	79,142
Total consumer loans | Acquired Loans | Direct installment | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	71	0
Total consumer loans | Acquired Loans | Residential mortgages
Credit Quality [Line Items]
Total Loans and Leases	666,465	397,798
Total consumer loans | Acquired Loans | Residential mortgages | Performing
Credit Quality [Line Items]
Total Loans and Leases	666,465	397,798
Total consumer loans | Acquired Loans | Residential mortgages | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	0	0
Total consumer loans | Acquired Loans | Indirect installment
Credit Quality [Line Items]
Total Loans and Leases	165	203
Total consumer loans | Acquired Loans | Indirect installment | Performing
Credit Quality [Line Items]
Total Loans and Leases	165	203
Total consumer loans | Acquired Loans | Indirect installment | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	0	0
Total consumer loans | Acquired Loans | Consumer lines of credit
Credit Quality [Line Items]
Total Loans and Leases	594,323	201,573
Total consumer loans | Acquired Loans | Consumer lines of credit | Performing
Credit Quality [Line Items]
Total Loans and Leases	592,384	201,061
Total consumer loans | Acquired Loans | Consumer lines of credit | Non-Performing
Credit Quality [Line Items]
Total Loans and Leases	$ 1,939	$ 512

Loans and Leases - Summary of I

Loans and Leases - Summary of Impaired Loans and Lease, by Class (Detail) - Originated Loans and Leases - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	$ 106,476	$ 93,479
Recorded Investment With No Specific Reserve	74,309	72,393
Recorded Investment With Specific Reserve	7,363	9,460
Total Recorded Investment	81,672	81,853
Specific Reserve	3,654	3,203
Average Recorded Investment	88,636	86,388
Commercial real estate
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	27,718	23,771
Recorded Investment With No Specific Reserve	21,748	19,699
Recorded Investment With Specific Reserve	2,906	464
Total Recorded Investment	24,654	20,163
Specific Reserve	439	13
Average Recorded Investment	24,413	19,217
Commercial and industrial
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	29,307	25,719
Recorded Investment With No Specific Reserve	11,595	14,781
Recorded Investment With Specific Reserve	4,457	8,996
Total Recorded Investment	16,052	23,777
Specific Reserve	3,215	3,190
Average Recorded Investment	23,907	29,730
Commercial leases
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	1,574	3,429
Recorded Investment With No Specific Reserve	1,574	3,429
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	1,574	3,429
Specific Reserve	0	0
Average Recorded Investment	1,386	3,394
Other
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	0	1,000
Recorded Investment With No Specific Reserve	0	1,000
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	0	1,000
Specific Reserve	0	0
Average Recorded Investment	0	1,000
Total commercial loans and leases
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	58,599	53,919
Recorded Investment With No Specific Reserve	34,917	38,909
Recorded Investment With Specific Reserve	7,363	9,460
Total Recorded Investment	42,280	48,369
Specific Reserve	3,654	3,203
Average Recorded Investment	49,706	53,341
Direct installment
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	19,375	16,440
Recorded Investment With No Specific Reserve	16,653	14,952
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	16,653	14,952
Specific Reserve	0	0
Average Recorded Investment	16,852	14,997
Residential mortgages
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	17,754	14,090
Recorded Investment With No Specific Reserve	16,410	13,367
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	16,410	13,367
Specific Reserve	0	0
Average Recorded Investment	15,984	13,200
Indirect installment
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	5,709	5,172
Recorded Investment With No Specific Reserve	2,435	2,180
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	2,435	2,180
Specific Reserve	0	0
Average Recorded Investment	2,279	2,037
Consumer lines of credit
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	5,039	3,858
Recorded Investment With No Specific Reserve	3,894	2,985
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	3,894	2,985
Specific Reserve	0	0
Average Recorded Investment	3,815	2,813
Total consumer loans
Financial Receivables Impaired Or Restructured [Line Items]
Unpaid Contractual Principal Balance	47,877	39,560
Recorded Investment With No Specific Reserve	39,392	33,484
Recorded Investment With Specific Reserve	0	0
Total Recorded Investment	39,392	33,484
Specific Reserve	0	0
Average Recorded Investment	$ 38,930	$ 33,047

Loans and Leases - Additional A

Loans and Leases - Additional Allowance for Credit Losses Relating to Acquired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	$ 175,380	$ 158,059	$ 142,012	$ 125,926
Acquired Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	6,698	7,268	$ 6,727	$ 7,974
Acquired Loans | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	4,976	4,538
Acquired Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	(415)	500
Acquired Loans | Total commercial loans and leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	4,561	5,038
Acquired Loans | Direct installment
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	1,553	1,005
Acquired Loans | Residential mortgages
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	484	632
Acquired Loans | Indirect installment
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	177	221
Acquired Loans | Consumer lines of credit
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	(77)	372
Acquired Loans | Total consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and leases receivable, allowance	$ 2,137	$ 2,230

Loans and Leases - Summary of P

Loans and Leases - Summary of Payment Status of Originated TDRs (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	$ 53,991	$ 46,933
Performing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	19,804	17,470
Non-Performing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	23,481	20,428
Non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	10,706	9,035
Originated Loans and Leases
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	50,183	46,392
Originated Loans and Leases | Performing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	19,538	17,105
Originated Loans and Leases | Non-Performing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	20,173	20,252
Originated Loans and Leases | Non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	10,472	9,035
Acquired Loans
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	3,808	541
Acquired Loans | Performing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	266	365
Acquired Loans | Non-Performing
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	3,308	176
Acquired Loans | Non-accrual
Financing Receivable, Modifications [Line Items]
Troubled debt restructurings ("TDRs")	$ 234	$ 0

Loans and Leases - Reserve for

Loans and Leases - Reserve for Commercial TDRs Included in Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Modifications [Line Items]
Reserves in allowance for loan losses	$ 175,380	$ 158,059	$ 142,012	$ 125,926
Specific reserves for commercial TDRs | Total commercial loans and leases
Financing Receivable, Modifications [Line Items]
Reserves in allowance for loan losses	95	291
Pooled reserves for individual commercial loans under $500 | Total commercial loans and leases
Financing Receivable, Modifications [Line Items]
Reserves in allowance for loan losses	$ 469	$ 276

Loans and Leases - Summary of T

Loans and Leases - Summary of Troubled Debt Restructurings by Class of Loans (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)Contract	Dec. 31, 2016USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	772	679
Pre-Modification Outstanding Recorded Investment	$ 13,954	$ 12,220
Post- Modification Outstanding Recorded Investment	$ 12,570	$ 11,222
Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	3	4
Pre-Modification Outstanding Recorded Investment	$ 1,608	$ 778
Post- Modification Outstanding Recorded Investment	$ 1,683	$ 737
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	3	3
Pre-Modification Outstanding Recorded Investment	$ 3,568	$ 1,727
Post- Modification Outstanding Recorded Investment	$ 3,091	$ 1,504
Total commercial loans and leases
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	6	7
Pre-Modification Outstanding Recorded Investment	$ 5,176	$ 2,505
Post- Modification Outstanding Recorded Investment	$ 4,774	$ 2,241
Direct installment
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	641	527
Pre-Modification Outstanding Recorded Investment	$ 5,107	$ 6,090
Post- Modification Outstanding Recorded Investment	$ 4,500	$ 5,566
Residential mortgages
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	43	45
Pre-Modification Outstanding Recorded Investment	$ 2,251	$ 2,155
Post- Modification Outstanding Recorded Investment	$ 2,095	$ 2,081
Indirect installment
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	18	19
Pre-Modification Outstanding Recorded Investment	$ 48	$ 51
Post- Modification Outstanding Recorded Investment	$ 43	$ 51
Consumer lines of credit
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	64	81
Pre-Modification Outstanding Recorded Investment	$ 1,372	$ 1,419
Post- Modification Outstanding Recorded Investment	$ 1,158	$ 1,283
Total consumer loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	766	672
Pre-Modification Outstanding Recorded Investment	$ 8,778	$ 9,715
Post- Modification Outstanding Recorded Investment	$ 7,796	$ 8,981

Loans and Leases - Summary of94

Loans and Leases - Summary of Originated Troubled Debt Restructurings by Class of Loans and Leases, Payment Default (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)Contract	Dec. 31, 2016USD ($)Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	160	118
Recorded Investment | $	$ 1,333	$ 1,027
Commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	1	0
Recorded Investment | $	$ 463	$ 0
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	0	0
Recorded Investment | $	$ 0	$ 0
Total commercial loans and leases
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	1	0
Recorded Investment | $	$ 463	$ 0
Direct installment
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	131	90
Recorded Investment | $	$ 358	$ 313
Residential mortgages
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	6	7
Recorded Investment | $	$ 314	$ 285
Indirect installment
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	17	18
Recorded Investment | $	$ 28	$ 35
Consumer lines of credit
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	5	3
Recorded Investment | $	$ 170	$ 394
Total consumer loans
Financing Receivable, Modifications [Line Items]
Number of Contracts | Contract	159	118
Recorded Investment | $	$ 870	$ 1,027

Allowance for Credit Losses - S

Allowance for Credit Losses - Summary of Changes in Allowance for Credit Losses by Loan and Lease Class (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				$ 158,059				$ 142,012	$ 158,059	$ 142,012	$ 125,926
Charge- Offs									(59,585)	(51,514)	(31,068)
Recoveries									15,833	11,809	6,713
Net Charge- Offs									(43,752)	(39,705)	(24,355)
Provision for credit losses	$ 16,699	$ 16,768	$ 16,756	10,850	$ 12,705	$ 14,639	$ 16,640	11,768	61,073	55,752	40,441
Balance at End of Year	175,380				158,059				175,380	158,059	142,012
Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				150,791				135,285	150,791	135,285	117,952
Charge- Offs									(57,883)	(50,466)	(30,174)
Recoveries									11,215	10,550	6,023
Net Charge- Offs									(46,668)	(39,916)	(24,151)
Provision for credit losses									64,559	55,422	41,484
Balance at End of Year	168,682				150,791				168,682	150,791	135,285
Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				7,268				6,727	7,268	6,727	7,974
Charge- Offs									(1,702)	(1,048)	(894)
Recoveries									4,618	1,259	690
Net Charge- Offs									2,916	211	(204)
Provision for credit losses									(3,486)	330	(1,043)
Balance at End of Year	6,698				7,268				6,698	7,268	6,727
Commercial real estate | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				46,635				41,741	46,635	41,741	37,588
Charge- Offs									(2,178)	(6,657)	(4,443)
Recoveries									2,311	3,669	1,117
Net Charge- Offs									133	(2,988)	(3,326)
Provision for credit losses									3,513	7,882	7,479
Balance at End of Year	50,281				46,635				50,281	46,635	41,741
Commercial real estate | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				4,538					4,538
Balance at End of Year	4,976				4,538				4,976	4,538
Commercial and industrial | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				47,991				41,023	47,991	41,023	32,645
Charge- Offs									(26,188)	(19,584)	(3,562)
Recoveries									1,275	2,508	1,773
Net Charge- Offs									(24,913)	(17,076)	(1,789)
Provision for credit losses									28,885	24,044	10,167
Balance at End of Year	51,963				47,991				51,963	47,991	41,023
Commercial and industrial | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				500					500
Balance at End of Year	(415)				500				(415)	500
Commercial leases | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				3,280				2,541	3,280	2,541	2,398
Charge- Offs									(1,017)	(962)	(544)
Recoveries									6	66	101
Net Charge- Offs									(1,011)	(896)	(443)
Provision for credit losses									3,377	1,635	586
Balance at End of Year	5,646				3,280				5,646	3,280	2,541
Other | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				1,392				1,013	1,392	1,013	759
Charge- Offs									(4,099)	(2,729)	(1,691)
Recoveries									1,255	131	55
Net Charge- Offs									(2,844)	(2,598)	(1,636)
Provision for credit losses									3,295	2,977	1,890
Balance at End of Year	1,843				1,392				1,843	1,392	1,013
Total commercial loans and leases | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				99,298				86,318	99,298	86,318	73,390
Charge- Offs									(33,482)	(29,932)	(10,240)
Recoveries									4,847	6,374	3,046
Net Charge- Offs									(28,635)	(23,558)	(7,194)
Provision for credit losses									39,070	36,538	20,122
Balance at End of Year	109,733				99,298				109,733	99,298	86,318
Total commercial loans and leases | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				5,038					5,038
Balance at End of Year	4,561				5,038				4,561	5,038
Direct installment | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				21,391				21,587	21,391	21,587	20,538
Charge- Offs									(12,401)	(10,153)	(10,844)
Recoveries									2,015	1,822	1,527
Net Charge- Offs									(10,386)	(8,331)	(9,317)
Provision for credit losses									9,931	8,135	10,366
Balance at End of Year	20,936				21,391				20,936	21,391	21,587
Direct installment | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				1,005					1,005
Balance at End of Year	1,553				1,005				1,553	1,005
Residential mortgages | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				10,082				7,909	10,082	7,909	8,024
Charge- Offs									(595)	(441)	(1,010)
Recoveries									184	74	85
Net Charge- Offs									(411)	(367)	(925)
Provision for credit losses									5,836	2,540	810
Balance at End of Year	15,507				10,082				15,507	10,082	7,909
Residential mortgages | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				632					632
Balance at End of Year	484				632				484	632
Indirect installment | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				10,564				9,889	10,564	9,889	7,504
Charge- Offs									(9,201)	(7,855)	(6,427)
Recoveries									3,708	2,015	1,190
Net Charge- Offs									(5,493)	(5,840)	(5,237)
Provision for credit losses									6,896	6,515	7,622
Balance at End of Year	11,967				10,564				11,967	10,564	9,889
Indirect installment | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				221					221
Balance at End of Year	177				221				177	221
Consumer lines of credit | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				9,456				9,582	9,456	9,582	8,496
Charge- Offs									(2,204)	(2,085)	(1,653)
Recoveries									461	265	175
Net Charge- Offs									(1,743)	(1,820)	(1,478)
Provision for credit losses									2,826	1,694	2,564
Balance at End of Year	10,539				9,456				10,539	9,456	9,582
Consumer lines of credit | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				372					372
Balance at End of Year	(77)				372				(77)	372
Total consumer loans | Originated Loans and Leases
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				51,493				48,967	51,493	48,967	44,562
Charge- Offs									(24,401)	(20,534)	(19,934)
Recoveries									6,368	4,176	2,977
Net Charge- Offs									(18,033)	(16,358)	(16,957)
Provision for credit losses									25,489	18,884	21,362
Balance at End of Year	58,949				51,493				58,949	51,493	48,967
Total consumer loans | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				2,230					2,230
Balance at End of Year	2,137				2,230				2,137	2,230
Purchased credit-impaired loans | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				572				834	572	834	660
Charge- Offs									(469)	(399)	(64)
Recoveries									36	42	19
Net Charge- Offs									(433)	(357)	(45)
Provision for credit losses									496	95	219
Balance at End of Year	635				572				635	572	834
Other acquired loans | Acquired Loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at Beginning of Year				$ 6,696				$ 5,893	6,696	5,893	7,314
Charge- Offs									(1,233)	(649)	(830)
Recoveries									4,582	1,217	671
Net Charge- Offs									3,349	568	(159)
Provision for credit losses									(3,982)	235	(1,262)
Balance at End of Year	$ 6,063				$ 6,696				$ 6,063	$ 6,696	$ 5,893

Allowance for Credit Losses -96

Allowance for Credit Losses - Summary of Individual and Collective Allowance for Credit Losses and Loan and Lease Balances by Class (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Originated loans and leases	$ 20,998,766	$ 14,896,943
Commercial real estate
Valuation Allowance [Line Items]
Originated loans and leases	8,741,864	5,435,162
Commercial and industrial
Valuation Allowance [Line Items]
Originated loans and leases	4,170,667	3,042,781
Commercial leases
Valuation Allowance [Line Items]
Originated loans and leases	266,720	196,636
Other
Valuation Allowance [Line Items]
Originated loans and leases	17,063	35,878
Total commercial loans and leases
Valuation Allowance [Line Items]
Originated loans and leases	13,196,314	8,710,457
Direct installment
Valuation Allowance [Line Items]
Originated loans and leases	1,905,535	1,844,399
Residential mortgages
Valuation Allowance [Line Items]
Originated loans and leases	2,702,691	1,844,574
Indirect installment
Valuation Allowance [Line Items]
Originated loans and leases	1,448,433	1,196,313
Consumer lines of credit
Valuation Allowance [Line Items]
Originated loans and leases	1,745,793	1,301,200
Total consumer loans
Valuation Allowance [Line Items]
Originated loans and leases	7,802,452	6,186,486
Originated Loans and Leases
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	3,654	3,203
Allowance, collectively evaluated for impairment	165,028	147,588
Originated loans and leases	15,345,490	12,547,987
Loans and leases outstanding, individually evaluated for impairment	20,986	34,719
Loans and leases outstanding, collectively evaluated for impairment	15,324,504	12,513,268
Originated Loans and Leases | Commercial real estate
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	439	13
Allowance, collectively evaluated for impairment	49,842	46,622
Originated loans and leases	5,174,783	4,095,817
Loans and leases outstanding, individually evaluated for impairment	11,114	12,973
Loans and leases outstanding, collectively evaluated for impairment	5,163,669	4,082,844
Originated Loans and Leases | Commercial and industrial
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	3,215	3,190
Allowance, collectively evaluated for impairment	48,748	44,801
Originated loans and leases	3,495,247	2,711,886
Loans and leases outstanding, individually evaluated for impairment	9,872	21,746
Loans and leases outstanding, collectively evaluated for impairment	3,485,375	2,690,140
Originated Loans and Leases | Commercial leases
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	5,646	3,280
Originated loans and leases	266,720	196,636
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	266,720	196,636
Originated Loans and Leases | Other
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	1,843	1,392
Originated loans and leases	17,063	35,878
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	17,063	35,878
Originated Loans and Leases | Total commercial loans and leases
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	3,654	3,203
Allowance, collectively evaluated for impairment	106,079	96,095
Originated loans and leases	8,953,813	7,040,217
Loans and leases outstanding, individually evaluated for impairment	20,986	34,719
Loans and leases outstanding, collectively evaluated for impairment	8,932,827	7,005,498
Originated Loans and Leases | Direct installment
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	20,936	21,391
Originated loans and leases	1,755,713	1,765,257
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	1,755,713	1,765,257
Originated Loans and Leases | Residential mortgages
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	15,507	10,082
Originated loans and leases	2,036,226	1,446,776
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	2,036,226	1,446,776
Originated Loans and Leases | Indirect installment
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	11,967	10,564
Originated loans and leases	1,448,268	1,196,110
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	1,448,268	1,196,110
Originated Loans and Leases | Consumer lines of credit
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	10,539	9,456
Originated loans and leases	1,151,470	1,099,627
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	1,151,470	1,099,627
Originated Loans and Leases | Total consumer loans
Valuation Allowance [Line Items]
Allowance, individually evaluated for impairment	0	0
Allowance, collectively evaluated for impairment	58,949	51,493
Originated loans and leases	6,391,677	5,507,770
Loans and leases outstanding, individually evaluated for impairment	0	0
Loans and leases outstanding, collectively evaluated for impairment	$ 6,391,677	$ 5,507,770

Loan Servicing - Mortgage Servi

Loan Servicing - Mortgage Servicing Rights Activity (Detail) (Details) - Mortgage Loan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Servicing Assets at Fair Value [Line Items]
SBA loans sold to investors with servicing retained	$ 3,256,548	$ 1,800,002
Mortgage loans sold with servicing retained	1,769,129	672,536	$ 431,617
Pretax gains resulting from above loan sales	21,683	12,519	10,681
Mortgage servicing fees	7,509	3,803	3,056
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance at beginning of period	13,521	8,921	6,859
Fair value of MSRs acquired	8,553	0	0
Additions	10,830	7,148	3,370
Payoffs and curtailments	(1,491)	(780)	(694)
Amortization	(2,360)	(1,768)	(614)
Balance at end of period	29,053	13,521	8,921
Fair value, beginning of period	17,546	11,503	8,684
Fair value, end of period	$ 32,419	$ 17,546	$ 11,503

Loan Servicing - Sensitivity of

Loan Servicing - Sensitivity of Fair Value to Changes in key Assumptions (Detail) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Mortgage Loan
Servicing Assets at Fair Value [Line Items]
Weighted average life (months)	80 months 12 days	79 months
Constant prepayment rate (annualized)	9.90%	9.90%
Discount rate	9.90%	9.80%
Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point two five percent favorable change in prepayment speed	$ 1,737	$ 692
Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point five zero percent favorable change in prepayment speed	3,220	1,288
Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point two five percent adverse change in prepayment speed	(1,937)	(789)
Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point five zero percent adverse change in prepayment speed	$ (4,007)	$ (1,680)
Small Business Administration Loans
Servicing Assets at Fair Value [Line Items]
Weighted average life (months)	63 months 16 days
Constant prepayment rate (annualized)	9.29%
Discount rate	14.87%
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 10 percent adverse change in prepayment speed	$ (145)
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 20 percent adverse change in prepayment speed	(284)
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 1 percent adverse change in prepayment speed	0
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 2 percent adverse change in prepayment speed	0
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 10 percent adverse change in discount rate	0
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 20 percent adverse change in discount rate	0
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 1 percent adverse change in discount rate	(147)
Sensitivity analysis of fair value, transferor's interests in transferred financial assets, impact of 2 percent adverse change in discount rate	$ (286)

Loan Servicing - Activity in SB

Loan Servicing - Activity in SBA-Guaranteed Loan Servicing Asset (Detail) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Servicing Assets at Fair Value [Line Items]
Service charges	$ 124,310	$ 97,524	$ 69,877
Mortgage Loan
Servicing Assets at Fair Value [Line Items]
SBA loans sold to investors with servicing retained	3,256,548	1,800,002
Mortgage loans sold with servicing retained	1,769,129	672,536	431,617
Pretax gains resulting from above loan sales	21,683	12,519	10,681
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	13,521	8,921	6,859
Additions	10,830	7,148	3,370
Amortization	2,360	1,768	614
Balance at end of period	29,053	13,521	8,921
Fair value, beginning of period	17,546	11,503	8,684
Fair value, end of period	32,419	17,546	$ 11,503
Small Business Administration Loans
Servicing Assets at Fair Value [Line Items]
SBA loans sold to investors with servicing retained	305,977
Mortgage loans sold with servicing retained	53,938
Pretax gains resulting from above loan sales	2,247
Service charges	2,195
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	0
Fair value of servicing rights acquired	5,399
Additions	959
Impairment (charge) / recovery	(281)
Amortization	1,019
Balance at end of period	5,058	0
Fair value, beginning of period	0
Fair value, end of period	5,058	$ 0
Valuation allowance for impairment of recognized servicing assets, balance	$ 300

Premises and Equipment - Summar

Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Land	$ 67,424	$ 45,640
Premises	239,807	186,784
Equipment	212,587	174,325
Property Plant and Equipment Gross	519,818	406,749
Accumulated depreciation	(183,278)	(162,793)
Total premises and equipment, net	$ 336,540	$ 243,956

Premises and Equipment - Deprec

Premises and Equipment - Depreciation Expense for Premises and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation expense for premises and equipment	$ 34,322	$ 23,355	$ 20,009

Premises and Equipment - Schedu

Premises and Equipment - Schedule of Rent Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Rental expense	$ 29,148	$ 21,015	$ 16,193

Premises and Equipment - Sum103

Premises and Equipment - Summary of Future Minimum Lease Payments (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Property, Plant and Equipment [Abstract]
2,018	$ 26,949
2,019	22,995
2,020	18,587
2,021	15,358
2,022	11,855
Later years	49,342
Total minimum rental commitment under leases	$ 145,086

Goodwill and Other Intangibl104

Goodwill and Other Intangible Assets - Rollforward of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 1,032,129	$ 833,086
Goodwill (deductions) additions	1,217,059	199,043
Goodwill, Ending Balance	2,249,188	1,032,129
Community Banking
Goodwill [Roll Forward]
Goodwill, Beginning Balance	1,011,599	812,399
Goodwill (deductions) additions	1,216,908	199,200
Goodwill, Ending Balance	2,228,507	1,011,599
Wealth Management
Goodwill [Roll Forward]
Goodwill, Beginning Balance	8,020	8,020
Goodwill (deductions) additions	151	0
Goodwill, Ending Balance	8,171	8,020
Insurance
Goodwill [Roll Forward]
Goodwill, Beginning Balance	10,701	10,858
Goodwill (deductions) additions	0	(157)
Goodwill, Ending Balance	10,701	10,701
Consumer Finance
Goodwill [Roll Forward]
Goodwill, Beginning Balance	1,809	1,809
Goodwill (deductions) additions	0	0
Goodwill, Ending Balance	$ 1,809	$ 1,809

Goodwill and Other Intangibl105

Goodwill and Other Intangible Assets - Summary of Core Deposit Intangibles, Customer Renewal Lists and Mortgage Servicing Rights (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 208,024	$ 152,238
Accumulated amortization	(115,949)	(98,432)
Net carrying amount	92,075	53,806
Core Deposit Intangibles
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	195,582	139,886
Accumulated amortization	(106,938)	(89,888)
Net carrying amount	88,644	49,998
Customer Renewal Lists
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	12,442	12,352
Accumulated amortization	(9,011)	(8,544)
Net carrying amount	$ 3,431	$ 3,808

Goodwill and Other Intangibl106

Goodwill and Other Intangible Assets - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017
Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization period of intangible assets, years	8 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization period of intangible assets, years	13 years
Core Deposit Intangibles
Finite-Lived Intangible Assets [Line Items]
Amortization period of intangible assets, years	10 years
Customer Renewal Lists | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization period of intangible assets, years	8 years
Customer Renewal Lists | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization period of intangible assets, years	13 years

Goodwill and Other Intangibl107

Goodwill and Other Intangible Assets - Schedule of Amortization Expense Recognized (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 17,517	$ 11,210	$ 8,305

Goodwill and Other Intangibl108

Goodwill and Other Intangible Assets - Schedule of Expected Amortization Expense on Finite-Lived Intangible Assets (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,018	$ 15,633
2,019	13,532
2,020	12,503
2,021	11,339
2,022	9,637
Total	$ 62,644

Deposits - Summary of Deposits

Deposits - Summary of Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Non-interest-bearing demand	$ 5,720,030	$ 4,205,337
Interest-bearing demand	9,571,038	6,931,381
Savings	2,488,178	2,352,434
Less than $100,000	2,461,014	1,680,068
$100,000 through $250,000	1,326,562	642,509
Greater than $250,000	832,903	253,918
Total Deposits	$ 22,399,725	$ 16,065,647

Deposits - Summary of Scheduled

Deposits - Summary of Scheduled Maturities of Certificates and Other Time Deposits (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
2,018	$ 2,778,467
2,019	1,026,222
2,020	351,431
2,021	194,678
2,022	118,891
Later years	150,790
Total	$ 4,620,479	$ 2,576,495

Short-Term Borrowings - Summary

Short-Term Borrowings - Summary of Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Securities sold under repurchase agreements	$ 256,017	$ 313,062
Federal Home Loan Bank advances	2,285,000	1,025,000
Federal funds purchased	1,000,000	1,037,000
Subordinated notes	137,320	127,948
Total short-term borrowings	$ 3,678,337	$ 2,503,010

Short-Term Borrowings - Schedul

Short-Term Borrowings - Schedule of Weighted Average Interest Rates on Short-Term Borrowings (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
Year-to-date average	1.16%	0.61%	0.42%
Period-end	1.44%	0.69%	0.48%

Long-Term Borrowings - Summary

Long-Term Borrowings - Summary of Long-Term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Federal Home Loan Bank advances	$ 310,061	$ 305,110
Subordinated notes	87,614	87,147
Junior subordinated debt	110,347	48,600
Other subordinated debt	160,151	98,637
Total long-term borrowings	$ 668,173	$ 539,494

Long-Term Borrowings - Schedule

Long-Term Borrowings - Scheduled Annual Maturities for Long-Term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
2,018	$ 69,684
2,019	151,558
2,020	105,610
2,021	52,189
2,022	6,072
Later years	283,060
Total long-term borrowings	$ 668,173	$ 539,494

Long-Term Borrowings - Addition

Long-Term Borrowings - Additional Information (Detail)	May 01, 2017USD ($)	Oct. 31, 2015USD ($)	Dec. 31, 2017USD ($)Trust	Dec. 31, 2016USD ($)	Mar. 11, 2017USD ($)
Debt Instrument [Line Items]
Number of unconsolidated subsidiary trusts | Trust			6
Percent of the common equity of each Trust owned by the Corporation			100.00%
FHLB
Debt Instrument [Line Items]
Credit available with FHLB			$ 7,931,000,000
Credit with FHLB used			$ 2,600,000,000
Federal Home Loan Bank advances are scheduled to mature periodically through the year			2,021
Omega Financial Capital Trust I
Debt Instrument [Line Items]
Redemption of corporation issued TPS				$ 10,000,000
4.875% Subordinated Notes Due in 2025
Debt Instrument [Line Items]
Aggregate principal amount		$ 100,000,000
Debt instrument interest rate percentage		4.875%
Proceeds from issuance of notes		$ 98,400,000
Long-term borrowings, carrying value			$ 98,800,000
7.25% Subordinated Notes Due in 2024
Debt Instrument [Line Items]
Aggregate principal amount					$ 15,500,000
Debt instrument interest rate percentage					7.25%
Long-term borrowings, carrying value			16,800,000
7.625% Subordinated Notes Due in 2023
Debt Instrument [Line Items]
Aggregate principal amount					$ 38,050,000
Debt instrument interest rate percentage					7.625%
Long-term borrowings, carrying value			$ 44,500,000
Minimum | FHLB
Debt Instrument [Line Items]
Effective interest rates			1.11%	0.95%
Minimum | Subordinated Notes
Debt Instrument [Line Items]
Months prior to maturity, interest discount			3 months
Maximum | FHLB
Debt Instrument [Line Items]
Effective interest rates			4.19%	4.19%
Maximum | Subordinated Notes
Debt Instrument [Line Items]
Months prior to maturity, interest discount			12 months
Yadkin Financial Corporation (YDKN)
Debt Instrument [Line Items]
Repayments of subordinated debt	$ 7,500,000

Long-Term Borrowings - Summa116

Long-Term Borrowings - Summary of Weighted Average Interest Rate on Subordinated Notes (Detail)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
Subordinated notes weighted average interest rate	2.85%	2.71%	2.73%

Long-Term Borrowings - Junior S

Long-Term Borrowings - Junior Subordinated Debt Trusts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 110,347	$ 48,600
Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	115,500
Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	3,885
F.N.B. Statutory Trust II
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 22,165
Stated Maturity Date	Jun. 15, 2036
Interest Rate	3.24%
Description of variable rate	LIBOR + 165 basis points (bps)
Basis points	1.65%
F.N.B. Statutory Trust II | Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 21,500
F.N.B. Statutory Trust II | Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	665
Omega Financial Capital Trust I
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 26,473
Stated Maturity Date	Oct. 18, 2034
Interest Rate	3.54%
Description of variable rate	LIBOR + 219 bps
Basis points	2.19%
Omega Financial Capital Trust I | Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 26,000
Omega Financial Capital Trust I | Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	1,114
Yadkin Valley Statutory Trust I
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 20,863
Stated Maturity Date	Dec. 15, 2037
Interest Rate	2.91%
Description of variable rate	LIBOR + 132 bps
Basis points	1.32%
Yadkin Valley Statutory Trust I | Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 25,000
Yadkin Valley Statutory Trust I | Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	774
FNB Financial Services Capital Trust I
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 21,804
Stated Maturity Date	Sep. 30, 2035
Interest Rate	2.80%
Description of variable rate	LIBOR + 146 bps
Basis points	1.46%
FNB Financial Services Capital Trust I | Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 25,000
FNB Financial Services Capital Trust I | Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	774
American Community Capital Trust II
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 10,448
Stated Maturity Date	Dec. 15, 2033
Interest Rate	4.14%
Description of variable rate	LIBOR + 280 bps
Basis points	2.80%
American Community Capital Trust II | Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 10,000
American Community Capital Trust II | Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	310
Crescent Financial Capital Trust I
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 8,594
Stated Maturity Date	Oct. 7, 2033
Interest Rate	4.46%
Description of variable rate	LIBOR + 310 bps
Basis points	3.10%
Crescent Financial Capital Trust I | Trust Preferred Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 8,000
Crescent Financial Capital Trust I | Common Securities
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 248

Derivative Instruments and H118

Derivative Instruments and Hedging Activities - Schedule of Notional Amounts and Gross Fair Values of Derivative Assets and Derivative Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional amount	$ 5,628,119	$ 4,005,212
Derivative asset, fair value, amount not offset against collateral	1,448	22,037
Derivative liability, fair value, amount not offset against collateral	13,581	35,217
Derivative asset, not subject to master netting arrangement	29,099	32,183
Derivative liability, not subject to master netting arrangement	15,616	12,050
Derivative asset	30,547	54,220
Derivative liabilities	29,197	47,267
Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, amount not offset against collateral	228	9,256
Derivative liability, fair value, amount not offset against collateral	1,982	1,171
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, amount not offset against collateral	1,169	12,720
Derivative liability, fair value, amount not offset against collateral	11,599	34,046
Derivative asset, not subject to master netting arrangement	27,233	32,170
Derivative liability, not subject to master netting arrangement	15,303	11,866
Equity Contracts
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, amount not offset against collateral	51	61
Derivative liability, fair value, amount not offset against collateral	0	0
Derivative asset, not subject to master netting arrangement	0	0
Derivative liability, not subject to master netting arrangement	51	61
Credit Risk Contracts
Derivatives, Fair Value [Line Items]
Notional amount	154,200
Derivative asset, not subject to master netting arrangement	39	13
Derivative liability, not subject to master netting arrangement	109	123
Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Derivative asset, not subject to master netting arrangement	1,594	0
Derivative liability, not subject to master netting arrangement	5	0
Forward Delivery Commitments
Derivatives, Fair Value [Line Items]
Derivative asset, not subject to master netting arrangement	233	0
Derivative liability, not subject to master netting arrangement	148	0
Subject to Master Netting Arrangement
Derivatives, Fair Value [Line Items]
Notional amount	2,951,622	2,140,337
Subject to Master Netting Arrangement | Interest Rate Contracts
Derivatives, Fair Value [Line Items]
Notional amount	705,000	450,000
Subject to Master Netting Arrangement | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Notional amount	2,245,442	1,689,157
Subject to Master Netting Arrangement | Equity Contracts
Derivatives, Fair Value [Line Items]
Notional amount	1,180	1,180
Not Subject to Master Netting Arrangement
Derivatives, Fair Value [Line Items]
Notional amount	2,676,497	1,864,875
Not Subject to Master Netting Arrangement | Interest Rate Swap
Derivatives, Fair Value [Line Items]
Notional amount	2,245,442	1,689,157
Not Subject to Master Netting Arrangement | Equity Contracts
Derivatives, Fair Value [Line Items]
Notional amount	1,180	1,180
Not Subject to Master Netting Arrangement | Credit Risk Contracts
Derivatives, Fair Value [Line Items]
Notional amount	235,196	174,538
Not Subject to Master Netting Arrangement | Interest Rate Lock Commitments
Derivatives, Fair Value [Line Items]
Notional amount	88,107	0
Not Subject to Master Netting Arrangement | Forward Delivery Commitments
Derivatives, Fair Value [Line Items]
Notional amount	$ 106,572	$ 0

Derivative Instruments and H119

Derivative Instruments and Hedging Activities - Summary of Key Data Related to Interest Rate (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	$ 5,628,119	$ 4,005,212
Fair value included in other assets	30,547	54,220
Fair value included in other liabilities	29,197	47,267
Designated as Hedging Instrument | Interest Rate Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	705,000	450,000
Fair value included in other assets	228	9,256
Designated as Hedging Instrument | Trading | Interest Rate Contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value included in other liabilities	1,982	1,171
Not Designated as Hedging Instrument | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount	4,490,884	3,378,314
Fair value included in other assets	28,402	44,890
Not Designated as Hedging Instrument | Trading | Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value included in other liabilities	$ 26,902	$ 45,912

Derivative Instrument and Hedgi

Derivative Instrument and Hedging Activities - Summary of Amounts Reclassified from Accumulated Other Comprehensive Income (AOCI) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassified from AOCI to interest expense	$ 41,049	$ 38,283	$ 32,619	$ 21,941	$ 17,885	$ 17,604	$ 16,562	$ 15,400	$ 133,892	$ 67,451	$ 48,573
Reclassification out of Accumulated Other Comprehensive Income [Member] | Before Tax Amount
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassified from AOCI to interest income									1,446	2,659
Reclassified from AOCI to interest expense									1,374	703
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Of Tax Amount
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassified from AOCI to interest income									940	1,728
Reclassified from AOCI to interest expense									$ 893	$ 457

Derivative Instruments and H121

Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional amount	$ 5,628,119,000	$ 4,005,212,000
Additional amount in excess of posted collateral required in case of breached agreements	$ 900,000	1,100,000
Interest Rate Contracts
Derivative [Line Items]
Maximum length of time hedged in interest rate cash flow hedge	6 years
Period to reclassification of cash flow hedge gain loss	12 months
Derivative gains to be reclassified within twelve months	$ 1,400,000
Derivative gains to be reclassified within twelve months, net of tax	900,000
Hedge ineffectiveness	0	0
Gains or losses from cash flow hedge derivatives reclassified to earnings	$ 0	0
Interest Rate Lock Commitments | Minimum
Derivative [Line Items]
Lock in period for interest rates	30 days
Interest Rate Lock Commitments | Maximum
Derivative [Line Items]
Lock in period for interest rates	90 days
Credit Risk Contracts
Derivative [Line Items]
Notional amount	$ 154,200,000
Maximum exposure under credit risk agreement assuming customer default	108,000	123,000
Credit risk derivatives, purchased at fair value	39,000	13,000
Credit risk derivatives, sold at fair value	$ (108,000)	$ (123,000)
Credit Risk Contracts | Minimum
Derivative [Line Items]
Risk participation agreements, term	6 months
Credit Risk Contracts | Maximum
Derivative [Line Items]
Risk participation agreements, term	9 years

Derivative Instruments and H122

Derivative Instruments and Hedging Activities - Derivative Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	$ 1,448	$ 22,037
Gross amounts not offset in the balance sheet financial instruments, derivative assets	1,448	1,378
Gross amounts not offset in the balance sheet cash collateral received, derivative assets	0	20,545
Net Amount	0	114
Interest Rate Contracts
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	228	9,256
Gross amounts not offset in the balance sheet financial instruments, derivative assets	228	843
Gross amounts not offset in the balance sheet cash collateral received, derivative assets	0	8,413
Net Amount	0	0
Interest Rate Swap
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	1,169	12,720
Gross amounts not offset in the balance sheet financial instruments, derivative assets	1,169	474
Gross amounts not offset in the balance sheet cash collateral received, derivative assets	0	12,132
Net Amount	0	114
Equity Contracts
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	51	61
Gross amounts not offset in the balance sheet financial instruments, derivative assets	51	61
Gross amounts not offset in the balance sheet cash collateral received, derivative assets	0	0
Net Amount	$ 0	$ 0

Derivative Instruments and H123

Derivative Instruments and Hedging Activities - Derivative Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	$ 13,581	$ 35,217
Gross amount not offset in the balance sheet financial instruments, derivative liabilities	12,922	16,661
Gross amount not offset in the balance sheet cash collateral pledged, derivative liabilities	0	17,651
Net Amount	659	905
Interest Rate Swap
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	11,599	34,046
Gross amount not offset in the balance sheet financial instruments, derivative liabilities	10,940	15,490
Gross amount not offset in the balance sheet cash collateral pledged, derivative liabilities	0	17,651
Net Amount	659	905
Interest Rate Contracts
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	1,982	1,171
Gross amount not offset in the balance sheet financial instruments, derivative liabilities	1,982	1,171
Gross amount not offset in the balance sheet cash collateral pledged, derivative liabilities	0	0
Net Amount	$ 0	$ 0

Derivative Instruments and H124

Derivative Instruments and Hedging Activities - Effect of Derivative Financial Instruments on Income Statement (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Interest Rate Contracts | Interest income – loans and leases
Derivative [Line Items]
Derivative financial instrument, net	$ 1,446	$ 2,659
Interest Rate Contracts | Interest expense – short-term borrowings
Derivative [Line Items]
Derivative financial instrument, net	1,374	703
Interest Rate Swap | Other income
Derivative [Line Items]
Derivative financial instrument, net	(592)	(529)
Credit Risk Contracts | Other income
Derivative [Line Items]
Derivative financial instrument, net	$ 40	$ 16

Commitments, Credit Risk and125

Commitments, Credit Risk and Contingencies - Summary of Off-Balance Sheet Credit Risk Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Extended credit and standby letters of credit	$ 132,904	$ 117,732
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Extended credit and standby letters of credit	$ 6,957,822	$ 4,486,164

Commitments, Credit Risk and126

Commitments, Credit Risk and Contingencies - Additional Information (Detail)	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Percentage of commitments to extend credit dependent upon the financial condition of the customers	76.80%

Stock Incentive Plans - Additio

Stock Incentive Plans - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Mar. 11, 2017	Apr. 06, 2013	Jun. 15, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards issued (in shares)	713,998	574,125	664,337
Common stock shares available under incentive compensation plans (in shares)	2,642,020
Unrecognized compensation expense	$ 12,099
Intrinsic value of outstanding and exercisable stock options	$ 4,400
Common shares available for purchase under warrants (in shares)						651,042
Annapolis Bancorp, Inc. (ANNB)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant issued, exercise price (in usd per share)	$ 3.04
Warrant issued, shares (in shares)					342,564
Warrants converted to purchase common stock (in shares)	402,287
Yadkin Financial Corporation (YDKN)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant issued, exercise price (in usd per share)	$ 9.50
Warrant issued, shares (in shares)				207,320
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards issued (in shares)	713,998	574,125	664,337
Unrecognized compensation expense	$ 12,100
Amount subject to accelerated vesting under Incentive Compensation Plan	$ 700
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for purchase under warrants (in shares)	1,302,083
Service- Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards issued, years	3 years
Unrecognized compensation expense	$ 7,037
Performance- Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 5,062
Performance- Based Awards | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards issued (in shares)	251,379	277,174
Performance- Based Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock percentage of number of units issued	175.00%
Performance- Based Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock percentage of number of units issued	0.00%
Market Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock percentage of number of units issued		100.00%
Warrant Expires in 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant issued, exercise price (in usd per share)	$ 11.52
Warrant Expires in 2019 | Annapolis Bancorp, Inc. (ANNB)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant issued, exercise price (in usd per share)					$ 3.57
Warrant Expires in 2019 | Yadkin Financial Corporation (YDKN)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant issued, exercise price (in usd per share)				$ 9.63
Warrant issued, shares (in shares)	210,135			207,320

Stock Incentive Plans - Schedul

Stock Incentive Plans - Schedule of Issuance of Restricted Stock Awards and Aggregate Weighted Average Grant Date Fair Values (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted stock awards (in shares)	713,998	574,125	664,337
Weighted average grant date fair values	$ 10,474	$ 7,383	$ 8,802

Stock Incentive Plans - Summary

Stock Incentive Plans - Summary of Information Concerning Restricted Stock Awards (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Awards
Shares, granted (in shares)	713,998	574,125	664,337
Shares, unvested shares outstanding at end of year (in shares)	1,975,862
Restricted Stock
Awards
Shares, unvested shares outstanding at beginning of year (in shares)	1,836,363	1,548,444	1,354,093
Shares, granted (in shares)	713,998	574,125	664,337
Shares, net adjustment due to performance (in shares)	(64,861)	72,070	13,115
Shares, vested (in shares)	(542,580)	(384,704)	(484,010)
Shares, forfeited (in shares)	(31,018)	(31,394)	(41,130)
Shares, dividend reinvestment (in shares)	63,960	57,822	42,039
Shares, unvested shares outstanding at end of year (in shares)	1,975,862	1,836,363	1,548,444
Weighted Average Grant Price per Share
Weighted average grant price per share, unvested shares outstanding at beginning of year (USD per share)	$ 12.97	$ 12.85	$ 11.86
Weighted average grant price per share, granted (USD per share)	14.67	12.86	13.25
Weighted average grant price per share, net adjustment due to performance (USD per share)	13.85	11.79	19.74
Weighted average grant price per share, vested (USD per share)	12.71	12.11	10.70
Weighted average grant price per share, forfeited (USD per share)	14.03	13.02	13.24
Weighted average grant price per share, dividend reinvestment (USD per share)	13.80	13.08	11.86
Weighted average grant price per share, unvested shares outstanding at end of year (USD per share)	$ 13.64	$ 12.97	$ 12.85

Stock Incentive Plans - Sche130

Stock Incentive Plans - Schedule of Certain Information Related to Restricted Stock Awards (Detail) - Restricted Stock - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 8,201	$ 7,066	$ 4,461
Tax benefit related to stock-based compensation expense	2,870	2,473	1,561
Fair value of awards vested	$ 8,106	$ 4,587	$ 6,070

Stock Incentive Plans - Compone

Stock Incentive Plans - Components of Restricted Stock Awards (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock awards (in shares) | shares	1,975,862
Unrecognized compensation expense	$ 12,099
Intrinsic value	$ 27,306
Weighted average remaining life (in years)	1 year 9 months 30 days
Service- Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock awards (in shares) | shares	1,062,902
Unrecognized compensation expense	$ 7,037
Intrinsic value	$ 14,689
Weighted average remaining life (in years)	1 year 11 months 5 days
Performance- Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock awards (in shares) | shares	912,960
Unrecognized compensation expense	$ 5,062
Intrinsic value	$ 12,617
Weighted average remaining life (in years)	1 year 8 months 18 days

Stock Incentive Plans - Summ132

Stock Incentive Plans - Summary of Activity Related to Stock Options Awards (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Options Outstanding and Exercisable
Shares, options outstanding at beginning of year (in shares)	892,532	435,340	568,834
Shares, assumed from acquisitions (in shares)	207,645	1,707,036	0
Shares, exercised (in shares)	(255,503)	(1,128,075)	(93,822)
Shares, forfeited (in shares)	(122,024)	(121,769)	(39,672)
Shares, options outstanding and exercisable at end of year (in shares)	722,650	892,532	435,340
Weighted Average Exercise Price per Share
Weighted average price per share, options outstanding at beginning of year (USD per share)	$ 8.95	$ 8.86	$ 8.86
Weighted average price per share, assumed from acquisition (USD per share)	8.92	7.83	0
Weighted average price per share, exercised (USD per share)	10.21	7.18	5.94
Weighted average price per share, forfeited (USD per share)	12.12	9.33	15.66
Weighted average price per share, options outstanding and exercisable at end of year (USD per share)	$ 7.96	$ 8.95	$ 8.86

Stock Incentive Plans - Summ133

Stock Incentive Plans - Summary of Stock Options Outstanding (Detail)	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding and Exercisable (in shares) | shares	722,650
$3.45 - $5.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding and Exercisable (in shares) | shares	162,224
Range of Exercise Prices, Minimum	$ 3.45
Range of Exercise Prices, Maximum	$ 5.18
Weighted Average Remaining Contractual Years	3 years 25 days
Weighted Average Exercise Price (USD per share)	$ 4.87
$5.19 - $7.78
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding and Exercisable (in shares) | shares	118,707
Range of Exercise Prices, Minimum	$ 5.19
Range of Exercise Prices, Maximum	$ 7.78
Weighted Average Remaining Contractual Years	3 years 3 months 21 days
Weighted Average Exercise Price (USD per share)	$ 6.84
$7.79 - $11.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding and Exercisable (in shares) | shares	432,260
Range of Exercise Prices, Minimum	$ 7.79
Range of Exercise Prices, Maximum	$ 11.68
Weighted Average Remaining Contractual Years	3 years 9 months 18 days
Weighted Average Exercise Price (USD per share)	$ 9.33
$11.69 - $14.53
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding and Exercisable (in shares) | shares	9,459
Range of Exercise Prices, Minimum	$ 11.69
Range of Exercise Prices, Maximum	$ 14.53
Weighted Average Remaining Contractual Years	8 months 8 days
Weighted Average Exercise Price (USD per share)	$ 12.48

Stock Incentive Plans - Summ134

Stock Incentive Plans - Summary of Stock Options Exercised (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Proceeds from stock options exercised	$ 2,340	$ 7,816	$ 557
Tax benefit recognized from stock options exercised	385	1,862	130
Intrinsic value of stock options exercised	$ 1,001	$ 6,577	$ 693

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017USD ($)RetirementPlansshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2008
Retirement Plans [Line Items]
Number of supplemental non-qualified retirement plans sponsored by the Corporation | RetirementPlans	2
Consecutive calendar years used to calculate BRP benefits			5 years
Term of employment for consideration of BRP			10 years
Percentage of non callable corporate bonds	A yield curve was produced for a universe containing the majority of U.S.-issued Aa-graded corporate bonds, all of which were non-callable (or callable with make-whole provisions), and after excluding the 10% of the bonds with the highest and lowest yields.
Corporation contribution	$ 1,345,000	$ 1,345,000
Benefits paid	$ 9,728,000	7,936,000
Percent of employer match	100.00%
Employee contribution percentage	6.00%
Additional discretionary contribution, annual financial goals, percentage	3.00%
Dividends received on common stock	$ 276,000	$ 276,000
Equity securities
Retirement Plans [Line Items]
Common stock, shares | shares	575,128	575,128
Percentage of common stock on total plan assets	4.90%	6.70%
Non Qualified Pension Plans
Retirement Plans [Line Items]
Benefits paid	$ 1,300,000	$ 1,300,000
Qualified Pension Plans
Retirement Plans [Line Items]
Corporation contribution	0	0
Benefits paid	$ 8,400,000	$ 6,600,000

Retirement Plans - Schedule of

Retirement Plans - Schedule of Accumulated Benefit Obligation, Change in Benefit Obligation, Change in Plan Assets, Plans' Funded Status and Amount Included in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Benefit Obligation
Accumulated benefit obligation	$ 181,412	$ 152,586
Projected benefit obligation at beginning of year	152,916	151,015
Acquisition	29,613	0
Service cost	(13)	(15)	$ (14)
Interest cost	6,846	6,129	5,897
Actuarial loss	9,061	3,723
Benefits paid	(9,728)	(7,936)
Settlement	(7,158)	0
Projected benefit obligation at end of year	181,537	152,916	151,015
Fair Value of Plan Assets
Fair value of plan assets at beginning of year	136,958	132,762
Acquisition	24,961	0
Actual return on plan assets	17,327	10,787
Corporation contribution	1,345	1,345
Benefits paid	(9,728)	(7,936)
Settlement	(7,158)	0
Fair value of plan assets at end of year	163,705	136,958	$ 132,762
Funded status of plans	$ (17,832)	$ (15,958)

Retirement Plans - Schedule 137

Retirement Plans - Schedule of Actuarial Assumptions Used in Determination of Projected Benefit Obligation (Detail)	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Weighted average discount rate	3.53%	3.96%
Rates of average increase in compensation levels	3.50%	3.50%

Retirement Plans - Schedule 138

Retirement Plans - Schedule of Net Periodic Pension Cost and Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Service cost	$ (13)	$ (15)	$ (14)
Interest cost	6,846	6,129	5,897
Expected return on plan assets	(11,121)	(9,413)	(9,964)
Transition amount amortization	0	0	0
Prior service credit amortization	7	7	7
Actuarial loss amortization	2,461	2,383	2,112
Net periodic pension income	(1,820)	(909)	(1,962)
Settlement charge	168	0	0
Total pension income	(1,652)	(909)	(1,962)
Current year actuarial loss	2,855	2,349	6,914
Amortization of actuarial loss	(2,461)	(2,383)	(2,112)
Amortization of prior service credit	(7)	(7)	(7)
Amortization of transition asset	0	0	0
Total amount recognized in other comprehensive income	387	(41)	4,795
Total amount recognized in net periodic benefit cost and other comprehensive income	$ (1,265)	$ (950)	$ 2,833

Retirement Plans - Schedule 139

Retirement Plans - Schedule of Actuarial Assumptions Used in Determination of Net Periodic Pension Cost (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Weighted average discount rate	3.96%	4.19%	3.85%
Rates of increase in compensation levels	3.50%	3.50%	3.50%
Expected long-term rate of return on assets	7.25%	7.25%	7.25%

Retirement Plans - Schedule 140

Retirement Plans - Schedule of Projected Benefit Obligation, Accumulated Benefit Obligation and Fair Value of Plan Assets for Qualified and Non-Qualified Pension Plans (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 181,537	$ 152,916	$ 151,015
Accumulated benefit obligation	181,412	152,586
Fair value of plan assets	163,705	136,958	$ 132,762
Qualified Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	161,632	132,902
Accumulated benefit obligation	161,632	132,902
Fair value of plan assets	163,705	136,958
Non-Qualified Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	19,905	20,014
Accumulated benefit obligation	19,780	19,684
Fair value of plan assets	$ 0	$ 0

Retirement Plans - Schedule 141

Retirement Plans - Schedule of Impact of Changes in Discount Rate, Return on Plan Assets on Pension Expense (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Retirement Benefits [Abstract]
0.5% decrease in the discount rate	$ (97)
0.5% decrease in the expected long-term rate of return on plan assets	$ 767

Retirement Plans - Schedule 142

Retirement Plans - Schedule of Estimated Future Cash Flows (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Retirement Benefits [Abstract]
Expected employer contributions: 2018	$ 1,424
Expected benefit payments: 2018	9,474
Expected benefit payments: 2019	9,957
Expected benefit payments: 2020	10,227
Expected benefit payments: 2021	10,390
Expected benefit payments: 2022	10,501
Expected benefit payments: 2023 - 2027	$ 53,902

Retirement Plans - Schedule 143

Retirement Plans - Schedule of Contribution Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
401(k) contribution expense	$ 12,286	$ 9,069	$ 8,055

Retirement Plans - Schedule 144

Retirement Plans - Schedule of Asset Allocations for Pension Plans (Detail)	Dec. 31, 2017	Dec. 31, 2016
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	64.00%	61.00%
Total debt securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	33.00%	35.00%
Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	3.00%	4.00%
Minimum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		45.00%
Minimum | Total debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		30.00%
Minimum | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		0.00%
Maximum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		65.00%
Maximum | Total debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		50.00%
Maximum | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Target Allocation		10.00%

Retirement Plans - Schedule 145

Retirement Plans - Schedule of Fair Value of Pension Plan Assets by Asset Category (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 163,705	$ 136,958	$ 132,762
Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,613	5,125
Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,948	9,219
Other equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	726	596
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,681	5,928
Fixed income securities: | U.S. Treasury
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	121
Fixed income securities: | U.S. government agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37,671	36,891
Fixed income securities: | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,532
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	120,381	100,067
Level 1 | Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,613	5,125
Level 1 | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,948	9,219
Level 1 | Other equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	726	596
Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,681	5,928
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	43,324	36,891
Level 2 | Fixed income securities: | U.S. Treasury
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	121
Level 2 | Fixed income securities: | U.S. government agencies
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37,671	36,891
Level 2 | Fixed income securities: | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,532
Small Cap Equities | U.S. equity funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,165	3,173
Small Cap Equities | Level 1 | U.S. equity funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,165	3,173
Mid-Cap Equities | U.S. equity funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9,413	7,615
Mid-Cap Equities | Level 1 | U.S. equity funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9,413	7,615
UNITED STATES | Fixed income mutual funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11,134	10,766
UNITED STATES | Level 1 | Fixed income mutual funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11,134	10,766
UNITED STATES | Large Cap Equities | U.S. equity index funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,489	559
UNITED STATES | Large Cap Equities | Level 1 | U.S. equity index funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,489	559
UNITED STATES | Small Cap Equities | U.S. equity index funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,983	3,035
UNITED STATES | Small Cap Equities | Level 1 | U.S. equity index funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,983	3,035
UNITED STATES | Mid-Cap Equities | U.S. equity index funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,836	3,795
UNITED STATES | Mid-Cap Equities | Level 1 | U.S. equity index funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,836	3,795
Non-US | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	576	718
Non-US | Mutual fund equity investments:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,965	9,555
Non-US | Fixed income mutual funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	414
Non-US | Level 1 | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	576	718
Non-US | Level 1 | Mutual fund equity investments:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,965	9,555
Non-US | Level 1 | Fixed income mutual funds:
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	414
Financial Services Sector | UNITED STATES | Large Cap Equities | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,269	2,999
Financial Services Sector | UNITED STATES | Large Cap Equities | Level 1 | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,269	2,999
Other Sectors | UNITED STATES | Large Cap Equities | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	45,583	36,570
Other Sectors | UNITED STATES | Large Cap Equities | Level 1 | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 45,583	$ 36,570

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Reclassification due to tax reform	$ 14,700
Effective income tax rate		44.10%	30.60%	30.50%
Income tax expense		$ 54,000
Unrecognized tax benefits	650	650	$ 542	$ 455
Unrecognized tax benefits relating to accrued interest, net of related federal tax benefits	25	25	$ 19
Unrecognized tax benefits which affect the effective tax rate if recognized	500	500
Reduction in the unrecognized tax benefit due to statutes of limitations for next twelve months	81	$ 81
Minimum
Income Tax Contingency [Line Items]
Expiration of unused state net operating loss carryforwards			2,018
Maximum
Income Tax Contingency [Line Items]
Expiration of unused state net operating loss carryforwards			2,037
Yadkin Financial Corporation (YDKN) | Maximum
Income Tax Contingency [Line Items]
Expiration of unused state net operating loss carryforwards		2,036
Yadkin Financial Corporation (YDKN) | Federal
Income Tax Contingency [Line Items]
Tax credit carryforward	5,200	$ 5,200
Operating loss carryforwards	65,500	65,500
Yadkin Financial Corporation (YDKN) | State
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 21,500	$ 21,500

Income Taxes - Summary of Incom

Income Taxes - Summary of Income Tax Expense Allocated Based on Separate Tax Return Basis (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Current income taxes: Federal taxes	$ 26,336	$ 57,894	$ 69,572
Current income taxes: State taxes	1,746	2,329	989
Total current income taxes	28,082	60,223	70,561
Deferred income taxes: Federal taxes	128,204	14,983	63
Deferred income taxes: State taxes	779	291	(631)
Total deferred income taxes	128,983	15,274	(568)
Total income taxes	$ 157,065	$ 75,497	$ 69,993

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation Between the Statutory Tax Rate and Actual Effective Tax Rate (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Statutory tax rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	0.50%	0.70%	0.80%
Valuation allowance reversal	0.00%	0.00%	(0.80%)
Tax-exempt interest	(3.30%)	(2.90%)	(2.20%)
Cash surrender value of life insurance	1.10%	1.50%	1.30%
Tax credits	(2.60%)	(0.90%)	(1.10%)
TCJA deferred tax corporate rate change	0.20%	0.00%	0.00%
Tax Cuts and Jobs Act revaluation of net deferred tax assets	15.20%	0.00%	0.00%
Other items	0.20%	0.20%	0.10%
Actual effective tax rate	44.10%	30.60%	30.50%
Income tax expense	$ 54

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense Related to Gains on Sale of Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax expense related to gains on sale of securities	$ 2,071	$ 249	$ 288

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets and Liabilities from Tax Effects of Temporary Differences (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Allowance for credit losses	$ 38,933	$ 56,090
Discounts on acquired loans	64,341	48,978
Net operating loss/tax credit carryforwards	47,376	17,753
Deferred compensation	8,534	12,236
Securities impairments	1,092	0
Pension and other defined benefit plans	6,768	7,713
Net unrealized securities losses	7,238	6,972
Other	7,787	11,264
Total	182,069	161,006
Valuation allowance	(26,620)	(18,945)
Total deferred tax assets	155,449	142,061
Loan costs	(7,211)	(2,222)
Depreciation	(12,263)	(12,392)
Prepaid expenses	(3,669)	(682)
Amortizable intangibles	(18,422)	(18,506)
Lease financing	(10,035)	(5,538)
Debt discharge income deferral	(474)	(1,361)
Originated mortgage servicing rights	(6,178)	(748)
Net unrealized securities gains	0	(86)
Other	(1,647)	(1,253)
Total deferred tax liabilities	(59,899)	(42,788)
Net deferred tax assets	$ 95,550	$ 99,273

Income Taxes - Summary of Re151

Income Taxes - Summary of Reconciliation of the Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Changes of Unrecognized Tax Benefits [Roll Forward]
Balance at beginning of year	$ 542	$ 455
Additions based on tax positions related to current year	186	163
Additions based on tax positions of prior year	0	0
Reductions for tax positions of prior years	(5)	0
Reductions due to expiration of statute of limitations	(73)	(76)
Balance at end of year	$ 650	$ 542

Other Comprehensive Income - Ch

Other Comprehensive Income - Changes in AOCI, Net of Tax, by Component (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		$ 2,571,617
Amounts reclassified from AOCI due to tax reform	$ (14,700)
Balance at end of period	4,409,194	4,409,194
Unrealized Net Gains (Losses) on Securities Available for Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		(18,222)
Other comprehensive income (loss) before reclassifications		(5,744)
Amounts reclassified from AOCI		(411)
Amounts reclassified from AOCI due to tax reform		(5,249)
Net current period other comprehensive income (loss)		(11,404)
Balance at end of period	(29,626)	(29,626)
Unrealized Net Gains (Losses) on Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		5,254
Other comprehensive income (loss) before reclassifications		(759)
Amounts reclassified from AOCI		(46)
Amounts reclassified from AOCI due to tax reform		958
Net current period other comprehensive income (loss)		153
Balance at end of period	5,407	5,407
Unrecognized Pension and Postretirement Obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		(48,401)
Other comprehensive income (loss) before reclassifications		(7)
Amounts reclassified from AOCI		0
Amounts reclassified from AOCI due to tax reform		(10,425)
Net current period other comprehensive income (loss)		(10,432)
Balance at end of period	(58,833)	(58,833)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		(61,369)
Other comprehensive income (loss) before reclassifications		(6,510)
Amounts reclassified from AOCI		(457)
Amounts reclassified from AOCI due to tax reform		(14,716)
Net current period other comprehensive income (loss)		(21,683)
Balance at end of period	$ (83,052)	$ (83,052)

Earnings Per Common Share - Com

Earnings Per Common Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income	$ 24,126	$ 77,693	$ 74,406	$ 22,979	$ 51,291	$ 52,168	$ 41,300	$ 26,132	$ 199,204	$ 170,891	$ 159,649
Less: Preferred stock dividends									8,041	8,041	8,041
Net Income Available to Common Stockholders	$ 22,115	$ 75,683	$ 72,396	$ 20,969	$ 49,280	$ 50,158	$ 39,290	$ 24,122	$ 191,163	$ 162,850	$ 151,608
Basic weighted average common shares outstanding (in shares)									302,195,295	206,244,498	174,971,785
Net effect of dilutive stock options, warrants and restricted stock (in shares)									1,662,681	1,524,111	1,367,168
Diluted weighted average common shares outstanding (in shares)									303,857,976	207,768,609	176,338,953
Basic (in usd per share)	$ 0.07	$ 0.23	$ 0.22	$ 0.09	$ 0.23	$ 0.24	$ 0.19	$ 0.12	$ 0.63	$ 0.79	$ 0.87
Diluted (in usd per share)	$ 0.07	$ 0.23	$ 0.22	$ 0.09	$ 0.23	$ 0.24	$ 0.19	$ 0.12	$ 0.63	$ 0.78	$ 0.86

Earnings Per Common Share - Sch

Earnings Per Common Share - Schedule of Average Shares Excluded from Diluted Earnings Per Common Share Calculation (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Average shares excluded from the diluted earnings per common share calculation (in shares)	910	9,980	18,167

Regulatory Matters - Schedule o

Regulatory Matters - Schedule of Capital Ratios (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital, actual amount	$ 2,666,272,000	$ 1,917,386,000
Tier 1 capital, actual amount	2,184,571,000	1,582,251,000
Common equity tier 1, actual amount	2,077,689,000	1,475,369,000
Leverage, actual amount	2,184,571,000	1,582,251,000
Risk weighted assets, actual amount	$ 23,403,622,000	$ 15,979,505,000
Total capital, actual ratio	11.40%	12.00%
Total capital, actual ratio tier 1 capital, actual ratio	9.30%	9.90%
Common equity tier 1, actual ratio	8.90%	9.20%
Leverage, actual ratio	7.60%	7.70%
Total capital, well-capitalized requirements amount	$ 2,340,362,000	$ 1,597,951,000
Tier 1 capital, well-capitalized requirements amount	1,872,290,000	1,278,360,000
Common equity tier 1, well-capitalized requirements amount	1,521,235,000	1,038,668,000
Leverage, well-capitalized requirements amount	$ 1,440,797,000	$ 1,027,831,000
Total capital, well-capitalized requirements ratio	10.00%	10.00%
Tier 1 capital, well-capitalized requirements ratio	8.00%	8.00%
Common equity tier 1, well-capitalized requirements ratio	6.50%	6.50%
Leverage, well-capitalized requirements ratio	5.00%	5.00%
Total capital, minimum capital requirements amount	$ 2,164,835,000	$ 1,378,232,000
Tier 1 capital, minimum capital requirements amount	1,696,763,000	1,058,642,000
Common equity tier 1, minimum capital requirements amount	1,345,708,000	818,950,000
Leverage, minimum capital requirements amount	$ 1,152,638,000	$ 822,265,000
Total capital, minimum capital requirements ratio	9.30%	8.60%
Tier 1 capital, minimum capital requirements ratio	7.30%	6.60%
Common equity tier 1, minimum capital requirements ratio	5.80%	5.10%
Leverage, minimum capital requirements ratio	4.00%	4.00%
FNBPA
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital, actual amount	$ 2,504,191,000	$ 1,768,561,000
Tier 1 capital, actual amount	2,332,892,000	1,614,167,000
Common equity tier 1, actual amount	2,252,892,000	1,534,167,000
Leverage, actual amount	2,332,892,000	1,614,167,000
Risk weighted assets, actual amount	$ 23,325,934,000	$ 15,889,893,000
Total capital, actual ratio	10.70%	11.10%
Total capital, actual ratio tier 1 capital, actual ratio	10.00%	10.20%
Common equity tier 1, actual ratio	9.70%	9.70%
Leverage, actual ratio	8.10%	7.90%
Total capital, well-capitalized requirements amount	$ 2,332,593,000	$ 1,588,989,000
Tier 1 capital, well-capitalized requirements amount	1,866,075,000	1,271,191,000
Common equity tier 1, well-capitalized requirements amount	1,516,186,000	1,032,843,000
Leverage, well-capitalized requirements amount	$ 1,432,604,000	$ 1,019,034,000
Total capital, well-capitalized requirements ratio	10.00%	10.00%
Tier 1 capital, well-capitalized requirements ratio	8.00%	8.00%
Common equity tier 1, well-capitalized requirements ratio	6.50%	6.50%
Leverage, well-capitalized requirements ratio	5.00%	5.00%
Total capital, minimum capital requirements amount	$ 2,157,649,000	$ 1,370,503,000
Tier 1 capital, minimum capital requirements amount	1,691,130,000	1,052,705,000
Common equity tier 1, minimum capital requirements amount	1,341,241,000	814,357,000
Leverage, minimum capital requirements amount	$ 1,146,084,000	$ 815,227,000
Total capital, minimum capital requirements ratio	9.30%	8.60%
Tier 1 capital, minimum capital requirements ratio	7.30%	6.60%
Common equity tier 1, minimum capital requirements ratio	5.80%	5.10%
Leverage, minimum capital requirements ratio	4.00%	4.00%

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail) $ in Millions	Dec. 31, 2017USD ($)
Banking and Thrift [Abstract]
Aggregate cash reserves with FRB	$ 39.6
Retained earnings available for distribution	206.8
Maximum amount loans that corporation can borrower under current provisions	$ 474.8

Cash Flow Information - Summary

Cash Flow Information - Summary of Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Cash Flows [Abstract]
Interest paid on deposits and other borrowings	$ 129,024	$ 67,296	$ 47,805
Income taxes paid	52,500	60,000	61,500
Transfers of loans to other real estate owned	34,841	14,592	9,628
Financing of other real estate owned sold	$ 19	$ 441	$ 372

Business Segments - Additional

Business Segments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2017Segment
Segment Reporting [Abstract]
Number of reportable segments	4

Business Segments - Financial I

Business Segments - Financial Information for Segments of FNB (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Interest income	$ 271,085	$ 263,514	$ 251,034	$ 194,693	$ 177,168	$ 175,110	$ 170,931	$ 155,754	$ 980,326	$ 678,963	$ 546,795
Interest expense	41,049	38,283	32,619	21,941	17,885	17,604	16,562	15,400	133,892	67,451	48,573
Net interest income	230,036	225,231	218,415	172,752	159,283	157,506	154,369	140,354	846,434	611,512	498,222
Provision for credit losses	16,699	16,768	16,756	10,850	12,705	14,639	16,640	11,768	61,073	55,752	40,441
Non-interest income									252,449	201,761	162,410
Non-interest expense									664,024	499,923	382,244
Amortization of intangibles									17,517	11,210	8,305
Income tax expense (benefit)									157,065	75,497	69,993
Net income (loss)	24,126	$ 77,693	$ 74,406	$ 22,979	51,291	$ 52,168	$ 41,300	$ 26,132	199,204	170,891	159,649
Total assets	31,417,635				21,844,817				31,417,635	21,844,817	17,557,662
Total intangibles	2,341,263				1,085,935				2,341,263	1,085,935	869,809
Operating Segments | Community Banking
Segment Reporting Information [Line Items]
Interest income									943,661	640,895	509,585
Interest expense									117,951	56,182	41,227
Net interest income									825,710	584,713	468,358
Provision for credit losses									52,780	49,046	33,045
Non-interest income									197,517	149,408	114,377
Non-interest expense									596,813	437,031	320,912
Amortization of intangibles									17,050	10,526	7,544
Income tax expense (benefit)									152,778	72,619	66,979
Net income (loss)									203,806	164,899	154,255
Total assets	31,155,973				21,629,374				31,155,973	21,629,374	17,349,459
Total intangibles	2,317,151				1,061,597				2,317,151	1,061,597	844,630
Operating Segments | Wealth Management
Segment Reporting Information [Line Items]
Interest income									0	0	0
Interest expense									0	0	0
Net interest income									0	0	0
Provision for credit losses									0	0	0
Non-interest income									39,256	35,283	35,246
Non-interest expense									30,563	27,201	27,264
Amortization of intangibles									254	259	273
Income tax expense (benefit)									2,679	2,845	2,803
Net income (loss)									5,760	4,978	4,906
Total assets	24,218				19,619				24,218	19,619	20,753
Total intangibles	10,176				10,189				10,176	10,189	10,447
Operating Segments | Insurance
Segment Reporting Information [Line Items]
Interest income									81	84	89
Interest expense									0	0	0
Net interest income									81	84	89
Provision for credit losses									0	0	0
Non-interest income									15,671	14,750	13,052
Non-interest expense									14,507	12,965	13,891
Amortization of intangibles									213	425	488
Income tax expense (benefit)									(256)	532	(412)
Net income (loss)									1,288	912	(826)
Total assets	21,062				22,053				21,062	22,053	22,207
Total intangibles	12,127				12,340				12,127	12,340	12,923
Operating Segments | Consumer Finance
Segment Reporting Information [Line Items]
Interest income									40,187	40,922	39,868
Interest expense									3,676	3,759	3,518
Net interest income									36,511	37,163	36,350
Provision for credit losses									8,293	6,706	7,396
Non-interest income									3,256	3,002	2,926
Non-interest expense									21,502	21,662	20,189
Amortization of intangibles									0	0	0
Income tax expense (benefit)									5,283	4,488	4,709
Net income (loss)									4,689	7,309	6,982
Total assets	181,260				193,349				181,260	193,349	195,048
Total intangibles	1,809				1,809				1,809	1,809	1,809
Parent and Other
Segment Reporting Information [Line Items]
Interest income									(3,603)	(2,938)	(2,747)
Interest expense									12,265	7,510	3,828
Net interest income									(15,868)	(10,448)	(6,575)
Provision for credit losses									0	0	0
Non-interest income									(3,251)	(682)	(3,191)
Non-interest expense									639	1,064	(12)
Amortization of intangibles									0	0	0
Income tax expense (benefit)									(3,419)	(4,987)	(4,086)
Net income (loss)									(16,339)	(7,207)	(5,668)
Total assets	35,122				(19,578)				35,122	(19,578)	(29,805)
Total intangibles	$ 0				$ 0				$ 0	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Measurements Disclosure [Line Items]
Percentage of securities using market-based information	100.00%
Minimum reserves for commercial loan	$ 500,000
Allocated allowance for loan losses	3,600,000
Fair value of allocated allowance	4,100,000
Estimated costs to sell	400,000
Provision for fair value measurements included in allowance for loan losses	3,700,000
Carrying amount of OREO	23,300,000
Written down of OREO	18,700,000
Fair value of OREO	21,300,000
Estimated cost to sell OREO	2,600,000
Loss from OREO included in earnings	$ 4,600,000
Short-term borrowings approximate fair value for amounts that mature, days, less than	90 days
Fair value, measurements, nonrecurring
Fair Value Measurements Disclosure [Line Items]
Impaired loans, carrying amount	$ 7,300,000
Allocated allowance for loan losses	4,110,000	$ 6,383,000
Fair value of OREO	21,336,000	14,198,000
Assets Still Held
Fair Value Measurements Disclosure [Line Items]
Change in unrealized gains or losses included in earnings relating to assets still held	0	$ 0
Equity securities
Fair Value Measurements Disclosure [Line Items]
Transfer of equity security to non-marketable equity securities, included in other assets	600,000
Yadkin Financial Corporation (YDKN) | Other debt securities
Fair Value Measurements Disclosure [Line Items]
Certain loans acquired in transfer not accounted for as debt securities, outstanding balance	$ 12,000,000

Fair Value Measurements - Balan

Fair Value Measurements - Balances of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	$ 2,764,562	$ 2,231,987
Loans held for sale	56,458	0
Derivative financial instruments	30,547	54,220
Derivative financial instruments	29,197	47,267
U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	0	29,953
U.S. government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	343,942	365,098
Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	794,957	535,974
Non-agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	1	897
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	0	1,291
States of the U.S. and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	21,093	35,849
Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	4,670	9,487
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	161	148
Derivative financial instruments	0	0
Derivative financial instruments	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	2,764,401	2,230,453
Derivative financial instruments	28,953	54,220
Derivative financial instruments	29,192	47,267
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total equity securities available for sale	0	1,386
Derivative financial instruments	1,594	0
Derivative financial instruments	5	0
Fair value, measurements, recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	2,763,537	2,231,347
Equity securities available for sale	1,025	640
Total equity securities available for sale	2,764,562	2,231,987
Loans held for sale	56,458
Derivative financial instruments	30,547	54,220
Total assets measured at fair value on a recurring basis	2,851,567	2,286,207
Derivative financial instruments	29,197	47,267
Total liabilities measured at fair value on a recurring basis	29,197	47,267
Fair value, measurements, recurring | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	29,953
Fair value, measurements, recurring | U.S. government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	343,942	365,098
Fair value, measurements, recurring | Agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1,598,874	1,252,798
Fair value, measurements, recurring | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	794,957	535,974
Fair value, measurements, recurring | Non-agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1	897
Fair value, measurements, recurring | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	1,291
Fair value, measurements, recurring | States of the U.S. and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	21,093	35,849
Fair value, measurements, recurring | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	4,670	9,487
Fair value, measurements, recurring | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	28,453	44,951
Fair value, measurements, recurring | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	2,094	9,269
Fair value, measurements, recurring | Fixed income mutual fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	161
Fair value, measurements, recurring | Financial services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	864	492
Fair value, measurements, recurring | Insurance services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0	148
Fair value, measurements, recurring | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	26,953	45,973
Fair value, measurements, recurring | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	2,244	1,294
Fair value, measurements, recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Equity securities available for sale	161	148
Total equity securities available for sale	161	148
Loans held for sale	0
Derivative financial instruments	0	0
Total assets measured at fair value on a recurring basis	161	148
Derivative financial instruments	0	0
Total liabilities measured at fair value on a recurring basis	0	0
Fair value, measurements, recurring | Level 1 | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | U.S. government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Non-agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | States of the U.S. and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Fair value, measurements, recurring | Level 1 | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Fair value, measurements, recurring | Level 1 | Fixed income mutual fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	161
Fair value, measurements, recurring | Level 1 | Financial services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0	0
Fair value, measurements, recurring | Level 1 | Insurance services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0	148
Fair value, measurements, recurring | Level 1 | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Fair value, measurements, recurring | Level 1 | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Fair value, measurements, recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	2,763,537	2,230,453
Equity securities available for sale	864	0
Total equity securities available for sale	2,764,401	2,230,453
Loans held for sale	56,458
Derivative financial instruments	28,953	54,220
Total assets measured at fair value on a recurring basis	2,849,812	2,284,673
Derivative financial instruments	29,192	47,267
Total liabilities measured at fair value on a recurring basis	29,192	47,267
Fair value, measurements, recurring | Level 2 | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	29,953
Fair value, measurements, recurring | Level 2 | U.S. government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	343,942	365,098
Fair value, measurements, recurring | Level 2 | Agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1,598,874	1,252,798
Fair value, measurements, recurring | Level 2 | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	794,957	535,974
Fair value, measurements, recurring | Level 2 | Non-agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	1	3
Fair value, measurements, recurring | Level 2 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	1,291
Fair value, measurements, recurring | Level 2 | States of the U.S. and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	21,093	35,849
Fair value, measurements, recurring | Level 2 | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	4,670	9,487
Fair value, measurements, recurring | Level 2 | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	28,453	44,951
Fair value, measurements, recurring | Level 2 | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	500	9,269
Fair value, measurements, recurring | Level 2 | Fixed income mutual fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0
Fair value, measurements, recurring | Level 2 | Financial services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	864	0
Fair value, measurements, recurring | Level 2 | Insurance services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0	0
Fair value, measurements, recurring | Level 2 | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	26,953	45,973
Fair value, measurements, recurring | Level 2 | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	2,239	1,294
Fair value, measurements, recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	894
Equity securities available for sale	0	492
Total equity securities available for sale	0	1,386
Loans held for sale	0
Derivative financial instruments	1,594	0
Total assets measured at fair value on a recurring basis	1,594	1,386
Derivative financial instruments	5	0
Total liabilities measured at fair value on a recurring basis	5	0
Fair value, measurements, recurring | Level 3 | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | U.S. government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | Agency mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | Agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | Non-agency collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	894
Fair value, measurements, recurring | Level 3 | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | States of the U.S. and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | Other debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Fair value, measurements, recurring | Level 3 | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	1,594	0
Fair value, measurements, recurring | Level 3 | Fixed income mutual fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0
Fair value, measurements, recurring | Level 3 | Financial services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0	492
Fair value, measurements, recurring | Level 3 | Insurance services industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities available for sale	0	0
Fair value, measurements, recurring | Level 3 | Trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	0	0
Fair value, measurements, recurring | Level 3 | Not for trading
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative financial instruments	$ 5	$ 0

Fair Value Measurements - Ad162

Fair Value Measurements - Additional Information about Assets Measured at Fair Value on Recurring Basis (Detail) - Fair value, measurements, recurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 1,386	$ 1,623
Included in earnings	4	0
Included in other comprehensive income	80	46
Accretion included in earnings	0	6
Purchases	13,642	0
Issuances	0	0
Sales/redemptions	(12,921)	0
Settlements	(4,588)	(289)
Transfers from Level 3	(578)	0
Transfers into Level 3	4,569	0
Balance at end of period	1,594	1,386
Other debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	0	0
Included in earnings	0	0
Included in other comprehensive income	0	0
Accretion included in earnings	(1)	0
Purchases	12,048	0
Issuances	0	0
Sales/redemptions	(12,047)	0
Settlements	0	0
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance at end of period	0	0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	492	439
Included in earnings	0	0
Included in other comprehensive income	86	53
Accretion included in earnings	0	0
Purchases	0	0
Issuances	0	0
Sales/redemptions	0	0
Settlements	0	0
Transfers from Level 3	(578)	0
Transfers into Level 3	0	0
Balance at end of period	0	492
Residential Non-Agency Collateralized Mortgage Obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	894	1,184
Included in earnings	4	0
Included in other comprehensive income	(6)	(7)
Accretion included in earnings	1	6
Purchases	0	0
Issuances	0	0
Sales/redemptions	(874)	0
Settlements	(19)	(289)
Transfers from Level 3	0	0
Transfers into Level 3	0	0
Balance at end of period	0	894
Interest Rate Lock Commitments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	0	0
Included in earnings	0	0
Included in other comprehensive income	0	0
Accretion included in earnings	0	0
Purchases	1,594	0
Issuances	0	0
Sales/redemptions	0	0
Settlements	(4,569)	0
Transfers from Level 3	0	0
Transfers into Level 3	4,569	0
Balance at end of period	$ 1,594	$ 0

Fair Value Measurements - Ad163

Fair Value Measurements - Additional Information about Assets Measured at Fair Value on Non-Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 3,600
Other real estate owned	21,300
Loans held for sale	56,458	$ 0
Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	4,110	6,383
Other real estate owned	21,336	14,198
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Level 1 | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Other real estate owned	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	0	0
Level 2 | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	2,813	500
Other real estate owned	10,513	11,017
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	37,758	17,546
Level 3 | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	1,297	5,883
Other real estate owned	10,823	3,181
Small Business Administration Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	5,058	$ 0
Small Business Administration Loans | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	36,432
Other assets	5,058
Small Business Administration Loans | Level 1 | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0
Other assets	0
Small Business Administration Loans | Level 2 | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	0
Other assets	0
Small Business Administration Loans | Level 3 | Fair value, measurements, nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held for sale	36,432
Other assets	$ 5,058

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Corporation's Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financial Assets
Cash and cash equivalents	$ 479,443	$ 371,407	$ 489,119	$ 287,393
Securities available for sale	2,764,562	2,231,987
Securities held to maturity	3,242,268	2,337,342
Securities held to maturity	3,218,379	2,294,777
Derivative financial instruments	30,547	54,220
Financial Liabilities
Financial Liabilities Deposits	22,399,725	16,065,647
Short-term borrowings	3,678,337	2,503,010
Long-term borrowings	668,173	539,494
Derivative liabilities	29,197	47,267
Carrying Amount
Financial Assets
Cash and cash equivalents	479,443	371,407
Securities available for sale	2,764,562	2,231,987
Securities held to maturity	3,242,268	2,337,342
Net loans and leases, including loans held for sale	20,916,277	14,750,792
Loan servicing rights	34,111	13,521
Derivative financial instruments	30,547	54,220
Accrued interest receivable	94,254	58,712
Financial Liabilities
Financial Liabilities Deposits	22,399,725	16,065,647
Short-term borrowings	3,678,337	2,503,010
Long-term borrowings	668,173	539,494
Derivative liabilities	29,197	47,267
Accrued interest payable	12,480	7,612
Fair Value
Financial Assets
Cash and cash equivalents	479,443	371,407
Securities available for sale	2,764,562	2,231,987
Securities held to maturity	3,218,379	2,294,777
Net loans and leases, including loans held for sale	20,661,196	14,464,274
Loan servicing rights	37,758	17,546
Derivative financial instruments	30,547	54,220
Accrued interest receivable	94,254	58,712
Financial Liabilities
Deposits	22,359,182	16,045,323
Short-term borrowings	3,678,723	2,503,277
Long-term borrowings	675,489	536,088
Derivative liabilities	29,197	47,267
Accrued interest payable	12,480	7,612
Level 1
Financial Assets
Cash and cash equivalents	479,443	371,407
Securities available for sale	161	148
Securities held to maturity	0	0
Net loans and leases, including loans held for sale	0	0
Loan servicing rights	0	0
Derivative financial instruments	0	0
Accrued interest receivable	94,254	58,712
Financial Liabilities
Deposits	17,779,246	13,489,152
Short-term borrowings	3,678,723	2,503,277
Long-term borrowings	0	0
Derivative liabilities	0	0
Accrued interest payable	12,480	7,612
Level 2
Financial Assets
Cash and cash equivalents	0	0
Securities available for sale	2,764,401	2,230,453
Securities held to maturity	3,218,379	2,293,091
Net loans and leases, including loans held for sale	56,458	0
Loan servicing rights	0	0
Derivative financial instruments	28,953	54,220
Accrued interest receivable	0	0
Financial Liabilities
Deposits	4,579,936	2,556,171
Short-term borrowings	0	0
Long-term borrowings	0	0
Derivative liabilities	29,192	47,267
Accrued interest payable	0	0
Level 3
Financial Assets
Cash and cash equivalents	0	0
Securities available for sale	0	1,386
Securities held to maturity	0	1,686
Net loans and leases, including loans held for sale	20,604,738	14,464,274
Loan servicing rights	37,758	17,546
Derivative financial instruments	1,594	0
Accrued interest receivable	0	0
Financial Liabilities
Deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	675,489	536,088
Derivative liabilities	5	0
Accrued interest payable	$ 0	$ 0

Parent Company Financial Sta165

Parent Company Financial Statements - Consolidated Balance Sheet of Parent Company Only (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 479,443	$ 371,407	$ 489,119	$ 287,393
Securities available for sale	2,764,562	2,231,987
Other assets	810,464	493,246
Total Assets	31,417,635	21,844,817	17,557,662
Other liabilities	262,206	165,049
Long-term borrowings	668,173	539,494
Long-term	87,614	87,147
Total Liabilities	27,008,441	19,273,200
Stockholders' Equity	4,409,194	2,571,617	2,096,182	2,021,456
Total Liabilities and Stockholders' Equity	31,417,635	21,844,817
Parent Company
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	165,698	164,276	$ 227,554	$ 129,320
Securities available for sale	864	492
Other assets	22,344	17,405
Total Assets	5,036,845	3,050,691
Other liabilities	33,000	26,063
Advances from affiliates	306,096	295,897
Long-term borrowings	279,536	147,916
Short-term	7,993	8,172
Long-term	1,026	1,026
Total Liabilities	627,651	479,074
Stockholders' Equity	4,409,194	2,571,617
Total Liabilities and Stockholders' Equity	5,036,845	3,050,691
Parent Company | Bank Subsidiary
Condensed Balance Sheet Statements, Captions [Line Items]
Investment in and advances to subsidiaries	4,553,703	2,598,520
Parent Company | Non-bank Subsidiaries
Condensed Balance Sheet Statements, Captions [Line Items]
Investment in and advances to subsidiaries	$ 294,236	$ 269,998

Parent Company Financial Sta166

Parent Company Financial Statements - Statements of Income of Parent Company Only (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:									$ 88	$ 34	$ 39
Interest income	$ 271,085	$ 263,514	$ 251,034	$ 194,693	$ 177,168	$ 175,110	$ 170,931	$ 155,754	980,326	678,963	546,795
Interest income									902	444	117
Interest expense	41,049	38,283	32,619	21,941	17,885	17,604	16,562	15,400	133,892	67,451	48,573
Income tax benefit									(157,065)	(75,497)	(69,993)
Net income	24,126	$ 77,693	$ 74,406	$ 22,979	51,291	$ 52,168	$ 41,300	$ 26,132	199,204	170,891	159,649
Parent Company
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:									158,210	117,479	95,443
Interest income									5,323	5,041	4,845
Interest income									100	2,799	1,053
Total Income									163,633	125,319	101,341
Interest expense									17,977	13,609	9,526
Other expenses									10,320	10,377	8,993
Total Expenses									28,297	23,986	18,519
Income Before Taxes and Equity in Undistributed Income of Subsidiaries									135,336	101,333	82,822
Income tax benefit									2,737	6,352	5,088
Income after income taxes									138,073	107,685	87,910
Equity in undistributed income (loss) of subsidiaries:	61,131				63,206				61,131	63,206	71,739
Net income									199,204	170,891	159,649
Parent Company | Bank [Member]
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:									149,000	108,954	87,580
Equity in undistributed income (loss) of subsidiaries:	60,567				60,924				60,567	60,924	71,581
Parent Company | Non-Bank [Member]
Condensed Income Statements, Captions [Line Items]
Dividend income from subsidiaries:									9,210	8,525	7,863
Equity in undistributed income (loss) of subsidiaries:	$ 564				$ 2,282				$ 564	$ 2,282	$ 158

Parent Company Financial Sta167

Parent Company Financial Statements - Statements of Cash Flows of Parent Company Only (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net income	$ 24,126	$ 77,693	$ 74,406	$ 22,979	$ 51,291	$ 52,168	$ 41,300	$ 26,132	$ 199,204	$ 170,891	$ 159,649
Other, net									(96,718)	10,702	(11,333)
Investing Activities
Proceeds from sale of securities available for sale									786,762	615,199	33,499
Net cash received in business combinations									196,964	245,762	144,629
Financing Activities
Decrease in long-term debt									(199,318)	(173,477)	(34,968)
Increase in long-term debt									155,399	46,357	134,953
Net proceeds from issuance of common stock									11,181	18,472	12,731
Tax benefit of stock-based compensation									0	1,813	28
Preferred stock									(8,041)	(8,041)	(8,041)
Common stock									(142,618)	(101,670)	(84,511)
Net (Decrease) Increase in Cash and Cash Equivalents									108,036	(117,712)	201,726
Cash and cash equivalents at beginning of year				371,407				489,119	371,407	489,119	287,393
Cash and Cash Equivalents at End of Year	479,443				371,407				479,443	371,407	489,119
Interest									129,024	67,296	47,805
Parent Company
Operating Activities
Net income									199,204	170,891	159,649
Undistributed earnings from subsidiaries	(61,131)				(63,206)				(61,131)	(63,206)	(71,739)
Other, net									5,441	(2,530)	680
Net cash flows provided by operating activities									143,514	105,155	88,590
Investing Activities
Proceeds from sale of securities available for sale									0	815	0
Net (increase) decrease in advances to subsidiaries									(9,838)	(6,263)	3,285
Payment for further investment in subsidiaries									(4,841)	(71,050)	(9,060)
Net cash received in business combinations									3,173	1,089	0
Net cash flows (used in) provided by investing activities									(11,506)	(75,409)	(5,775)
Financing Activities
Net decrease in advance from affiliate									10,018	6,356	(2,797)
Net decrease in short-term borrowings									(179)	(44)	(135)
Decrease in long-term debt									(1,510)	(10,291)	(650)
Increase in long-term debt									563	381	98,794
Net proceeds from issuance of common stock									11,181	18,472	12,731
Tax benefit of stock-based compensation									0	1,813	28
Preferred stock									(8,041)	(8,041)	(8,041)
Common stock									(142,618)	(101,670)	(84,511)
Net cash flows (used in) provided by financing activities									(130,586)	(93,024)	15,419
Net (Decrease) Increase in Cash and Cash Equivalents									1,422	(63,278)	98,234
Cash and cash equivalents at beginning of year				$ 164,276				$ 227,554	164,276	227,554	129,320
Cash and Cash Equivalents at End of Year	$ 165,698				$ 164,276				165,698	164,276	227,554
Interest									$ 15,807	$ 13,620	$ 8,309

Quarterly Earnings Summary (168

Quarterly Earnings Summary (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Earnings Summary (Unaudited) [Abstract]
Interest income	$ 271,085	$ 263,514	$ 251,034	$ 194,693	$ 177,168	$ 175,110	$ 170,931	$ 155,754	$ 980,326	$ 678,963	$ 546,795
Interest expense	41,049	38,283	32,619	21,941	17,885	17,604	16,562	15,400	133,892	67,451	48,573
Net interest income	230,036	225,231	218,415	172,752	159,283	157,506	154,369	140,354	846,434	611,512	498,222
Provision for credit losses	16,699	16,768	16,756	10,850	12,705	14,639	16,640	11,768	61,073	55,752	40,441
Net securities gains	21	2,777	493	2,625	116	299	226	71	5,916	712	822
Other non-interest income	65,083	63,374	65,585	52,491	50,950	52,941	51,185	45,973	16,480	12,730	13,865
Total non-interest expense	166,529	163,743	163,714	187,555	123,806	121,050	129,629	136,648	681,541	511,133	390,549
Net income	24,126	77,693	74,406	22,979	51,291	52,168	41,300	26,132	199,204	170,891	159,649
Net income available to common stockholders	$ 22,115	$ 75,683	$ 72,396	$ 20,969	$ 49,280	$ 50,158	$ 39,290	$ 24,122	$ 191,163	$ 162,850	$ 151,608
Earnings per Common Share
Basic (in usd per share)	$ 0.07	$ 0.23	$ 0.22	$ 0.09	$ 0.23	$ 0.24	$ 0.19	$ 0.12	$ 0.63	$ 0.79	$ 0.87
Diluted (in usd per share)	0.07	0.23	0.22	0.09	0.23	0.24	0.19	0.12	0.63	0.78	0.86
Cash Dividends per Common Share (in usd per share)	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.48	$ 0.48	$ 0.48