Hancock Whitney Corporation - 6 (HWC) 10-Q 9 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	HANCOCK HOLDING CO
Entity Filer Category	Large Accelerated Filer
Entity Central Index Key	750,577
Trading Symbol	hbhc
Amendment Flag	false
Document Type	10-Q
Document Fiscal Period Focus	Q1
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		85,287,037

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets:
Cash and due from banks	$ 253,860	$ 386,948
Interest-bearing bank deposits	61,288	92,157
Federal funds sold	253	227
Securities available for sale, at fair value (amortized cost of $3,008,951 and $2,949,057)	2,915,648	2,910,869
Securities held to maturity (fair value of $2,952,295 and $2,962,010)	3,014,428	2,977,511
Loans held for sale	21,827	39,865
Loans	19,092,504	19,004,163
Less: allowance for loan losses	(210,713)	(217,308)
Loans, net	18,881,791	18,786,855
Property and equipment, net of accumulated depreciation of $218,540 and $214,998	334,254	333,663
Prepaid expense	29,669	28,015
Other real estate, net	13,963	14,862
Accrued interest receivable	80,812	82,191
Goodwill	745,523	745,523
Other intangible assets, net	85,021	90,640
Life insurance contracts	544,427	541,081
Deferred tax asset, net	52,735	53,979
Other assets	261,838	251,700
Total assets	27,297,337	27,336,086
Deposits
Noninterest-bearing	8,230,060	8,307,497
Interest-bearing	14,255,662	13,945,705
Total deposits	22,485,722	22,253,202
Short-term borrowings	1,452,097	1,703,890
Long-term debt	300,443	305,513
Accrued interest payable	11,801	8,680
Other liabilities	151,236	179,852
Total liabilities	24,401,299	24,451,137
Stockholders' equity:
Common Stock	292,716	292,716
Capital surplus	1,723,689	1,718,117
Retained earnings	1,060,182	1,008,518
Accumulated other comprehensive loss, net	(180,549)	(134,402)
Total stockholders' equity	2,896,038	2,884,949
Total liabilities and stockholders' equity	$ 27,297,337	$ 27,336,086
Common shares authorized (par value of 3.33 per share)	350,000	350,000
Common shares issued	87,903	87,903
Common shares outstanding	85,285	85,200

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Consolidated Balance Sheets [Abstract]
Securities available for sale, amortized cost	$ 3,008,951	$ 2,949,057
Securities held to maturity, fair value	2,952,295	2,962,010
Property and equipment, accumulated depreciation	$ 218,540	$ 214,998
Common stock, par value per share	$ 3.33	$ 3.33

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest income:
Loans, including fees	$ 205,847	$ 172,781
Loans held for sale	221	217
Securities-taxable	29,301	23,367
Securities-tax exempt	5,537	5,407
Short-term investments	489	743
Total interest income	241,395	202,515
Interest expense:
Deposits	26,959	12,819
Short-term borrowings	5,351	2,941
Long-term debt	3,421	5,064
Total interest expense	35,731	20,824
Net interest income	205,664	181,691
Provision for loan losses	12,253	15,991
Net interest income after provision for loan losses	193,411	165,700
Noninterest income:
Service charges on deposit accounts	21,448	19,206
Trust fees	11,335	11,211
Bank card and ATM fees	14,458	12,468
Investment and annuity fees and insurance commissions	6,125	5,264
Secondary mortgage market operations	3,401	3,567
Other income	9,485	11,775
Total noninterest income	66,252	63,491
Noninterest expense:
Compensation expense	80,100	73,099
Employee benefits	19,874	19,080
Personnel expense	99,974	92,179
Net occupancy expense	11,010	10,757
Equipment expense	3,546	3,714
Data processing expense	16,449	15,397
Professional services expense	9,255	11,276
Amortization of intangibles	5,618	4,705
Telecommunications and postage	3,850	3,467
Deposit insurance and regulatory fees	7,948	6,490
Other real estate (income) expense, net	210	(13)
Other expense	12,931	15,570
Total noninterest expense	170,791	163,542
Income before income taxes	88,872	65,649
Income taxes	16,397	16,635
Net income	$ 72,475	$ 49,014
Earnings per common share-basic	$ 0.83	$ 0.57
Earnings per common share-diluted	0.83	0.57
Dividends paid per share	$ 0.24	$ 0.24
Weighted average shares outstanding-basic	85,241	84,365
Weighted average shares outstanding-diluted	85,423	84,624

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 72,475	$ 49,014
Other comprehensive income before income taxes:
Net change in unrealized gain/loss on available for sale securities and hedges	(62,244)	1,184
Reclassification of net losses realized and included in earnings	1,796	1,387
Amortization of unrealized net loss on securities transferred to held to maturity	755	650
Other comprehensive income/loss before income taxes	(59,693)	3,221
Income tax expense (benefit)	(13,546)	1,201
Other comprehensive income/loss net of income taxes	(46,147)	2,020
Comprehensive income	$ 26,328	$ 51,034

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), Net [Member]	Total
Balance at Dec. 31, 2016	$ 291,358	$ 1,698,253	$ 850,689	$ (120,532)	$ 2,719,768
Balance, Shares Issued at Dec. 31, 2016	87,495
Net income			49,014		49,014
Other comprehensive income				2,020	2,020
Comprehensive income			49,014	2,020	51,034
Cash dividends declared ($0.24 per common share)			(20,793)		(20,793)
Common stock activity, long-term incentive plan		12,815	43		12,858
Issuance of stock from dividend reinvestment and stock repurchase plans		755			755
Balance at Mar. 31, 2017	$ 291,358	1,711,823	878,953	(118,512)	2,763,622
Balance, Shares Issued at Mar. 31, 2017	87,495
Balance at Dec. 31, 2017	$ 292,716	1,718,117	1,008,518	(134,402)	$ 2,884,949
Balance, Shares Issued at Dec. 31, 2017	87,903				87,903,000
Net income			72,475		$ 72,475
Other comprehensive income				(46,147)	(46,147)
Comprehensive income			72,475	(46,147)	26,328
Cash dividends declared ($0.24 per common share)			(20,881)		(20,881)
Common stock activity, long-term incentive plan		4,735	70		4,805
Issuance of stock from dividend reinvestment and stock repurchase plans		837			837
Balance at Mar. 31, 2018	$ 292,716	$ 1,723,689	$ 1,060,182	$ (180,549)	$ 2,896,038
Balance, Shares Issued at Mar. 31, 2018	87,903				87,903,000

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Retained Earnings [Member]
Cash dividends declared, per common share	$ 0.24	$ 0.24

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 72,475	$ 49,014
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,551	6,915
Provision for loan losses	12,253	15,991
(Gain) loss on other real estate owned	210	(54)
Deferred tax expense	14,790	7,156
Increase in cash surrender value of life insurance contracts	(3,346)	(3,636)
Loss on disposal of other assets	73	229
Loss on sale of business	1,145
Net decrease in loans held for sale	18,172	13,966
Net amortization of securities premium/discount	8,453	7,323
Amortization of intangible assets	5,618	4,705
Amortization of FDIC indemnification assets		1,100
Stock-based compensation expense	4,883	4,209
Decrease in interest payable and other liabilities	(32,568)	(33,323)
Net payments to FDIC for loss share claims		(1,131)
Decrease in FDIC loss share receivable		902
Decrease in payable to FDIC for loan servicing	(11,107)
Decrease in other assets	6,821	21,362
Other, net	71	1,600
Net cash provided by operating activities	104,494	96,328
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities of securities available for sale	80,155	81,116
Purchases of securities available for sale	(142,052)	(60,484)
Proceeds from maturities of securities held to maturity	93,408	92,684
Purchases of securities held to maturity	(134,020)	(87,847)
Net decrease in short-term investments	30,843	9,428
Proceeds from sale of loans	12,211	33,279
Net increase in loans	(196,328)	(306,745)
Purchases of property and equipment	(7,904)	(7,329)
Proceeds from sales of property and equipment	42	17
Proceeds from sales of other real estate	1,641	3,099
Cash paid for acquisition, net of cash received		(322,708)
Proceeds from the sale of business, net of cash sold	77,081
Other, net	(8,915)	(39,588)
Net cash used in investing activities	(193,838)	(605,078)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in deposits	232,638	99,583
Net increase (decrease) in short-term borrowings	(251,793)	385,777
Repayments of long-term debt	(5,268)	(4,475)
Net proceeds from issuance of long-term debt	83	41
Dividends paid	(20,881)	(20,793)
Payroll tax remitted on net share settlement of equity awards	(142)	(163)
Proceeds from exercise of stock options	782	8,650
Proceeds from dividend reinvestment and stock purchase plans	837	755
Net cash provided by (used in) financing activities	(43,744)	469,375
NET DECREASE IN CASH AND DUE FROM BANKS	(133,088)	(39,375)
CASH AND DUE FROM BANKS, BEGINNING	386,948	372,689
CASH AND DUE FROM BANKS, ENDING	253,860	333,314
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 1,305	$ 1,031

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Basis of Presentation [Abstract]
Basis of Presentation	HANCOCK HOLDING COMPANY AND SUBSIDIARIES NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS  1. Basis of Presentation The consolidated financial statements include the accounts of Hancock Holding Company and all other entities in which it has a controlling interest (the “Company”). The financial statements include all adjustments that are, in the opinion of management, necessary to fairly state the Company’s financial condition, results of operations, changes in stockholders’ equity and cash flows for the interim periods presented. The Company has also evaluated all subsequent events for potential recognition and disclosure through the date of the filing of this Quarterly Report on Form 10-Q. Some financial information and disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) have been condensed or omitted in this Quarterly Report on Form 10-Q pursuant to Securities and Exchange Commission rules and regulations. These financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Financial information reported in these financial statements is not necessarily indicative of the Company’s financial condition, results of operations, or cash flows for any other interim or annual period. Certain prior period amounts have been reclassified to conform to the current period presentation. These changes in presentation did not have a material impact on the Company’s financial condition or operating results. Use of Estimates The accounting principles the Company follows and the methods for applying these principles conform to GAAP and general practices followed by the banking industry. These accounting principles require management to make estimates and assumptions about future events that affect the amounts reported in the consolidated financial statements and the accompanying notes. Actual results could differ from those estimates. Critical Accounting Policies and Estimates  There were no material changes or developments during the reporting period with respect to methodologies that the Company uses when applying what management believes are critical accounting policies and developing critical accounting estimates as disclosed in its Annual Report on Form 10-K for the year ended December 31, 2017. Refer to Note 15 – Recent Accounting Pronouncements for a discussion of accounting standards adopted during the quarter ended March 31, 2018. 

Acquisitions and Divestiture

Acquisitions and Divestiture	3 Months Ended
	Mar. 31, 2018
Acquisitions and Divestiture [Abstract]
Acquisitions and Divestiture	2. Acquisitions and Divestiture  On March 10, 2017, the Company , through its banking subsidiary, Whitney Bank (“Whitney”), acquired certain assets and assumed certain liabilities, including nine branches, from First NBC Bank (“FNBC”), referred to as the FNBC I transaction. Whitney paid approximately $323 million in cash consideration ( $326 million cash paid net of $3 million in branch cash acquired), including a $41.6 million transaction premium for the earnings stream acquired.  On April 28, 2017, the Louisiana Office of Financial Institutions (“OFI”) closed FNBC and appointed the FDIC as receiver. Whitney entered into a purchase and assumption agreement with the FDIC , referred to as the FNBC II transaction . Pursuant to the agreement, Whitney acquired selected assets and assumed selected liabilities of the former FNBC , including substantially all of the transaction and savings deposits. Whitney paid a premium of $35 million to the FDIC for the earnings stream acquired and received approximately $ 800 million in cash ( $64 2 million from the FDIC for the net liabilities assumed and $158 million in branch cash acquired). The terms of the a greement require the FDIC to indemnify Whitney against certain liabilities of FNBC and its affiliates not assumed or otherwise purchased by Whitney. Neither the Company nor Whitney Bank acquired any assets, common stock, preferred stock or debt, or assume d any other obligations, of First NBC Bank Holding Company.  Pending Business Combination  In December 2017, the Company announced entry into an agreement to acquire the bank-managed high net worth individual and institutional investment management and trust business from Capital One, National Association (“Capital One”). The transaction is expected to close in early third quarter 2018, pending regulatory approval and the satisfaction of customary and other closing conditions.  Divestiture  On March 9, 2018, the Company sold its consumer finance subsidiary, Harrison Finance Company (“HFC”). The Company recorded a loss on the sale of $1.1 million based on the preliminary cash settlement of $78.3 million, with a final cash settlement expected to occur in the second quarter of 2018.

Securities

Securities	3 Months Ended
	Mar. 31, 2018
Securities [Abstract]
Securities	3 . Securities The amortized cost , gross unrealized gains and losses, and estimated fair value of securities classified as available for sale and held to maturity follow.      Securities Available for Sale  (in thousands) March 31, 2018 December 31, 2017  Gross Gross Gross Gross  Amortized Unrealized Unrealized Fair Amortized Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  U.S. Treasury and government agency securities $ 97,431 — 3,547 93,884 $ 99,535 $ — $ 2,263 $ 97,272  Municipal obligations 245,164 211 8,084 237,291 245,997 1,135 3,346 243,786  Residential mortgage-backed securities 1,787,382 3,552 47,391 1,743,543 1,729,989 5,611 20,387 1,715,213  Commercial mortgage-backed securities 715,360 — 35,088 680,272 704,518 480 17,863 687,135  Collateralized mortgage obligations 158,114 — 2,956 155,158 165,518 4 1,559 163,963  Corporate debt securities 5,500 — — 5,500 3,500 — — 3,500  $ 3,008,951 $ 3,763 $ 97,066 $ 2,915,648 $ 2,949,057 $ 7,230 $ 45,418 $ 2,910,869      Securities Held to Maturity  (in thousands) March 31, 2018 December 31, 2017  Gross Gross Gross Gross  Amortized Unrealized Unrealized Fair Amortized Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  U.S. Treasury and government agency securities $ 50,000 — 576 49,424 $ 50,000 $ — $ 289 $ 49,711  Municipal obligations 707,581 1,315 13,453 695,443 723,094 8,323 4,245 727,172  Residential mortgage-backed securities 695,655 721 10,624 685,752 725,748 4,175 2,690 727,233  Commercial mortgage-backed securities 316,966 — 11,400 305,566 317,185 40 3,915 313,310  Collateralized mortgage obligations 1,244,226 391 28,507 1,216,110 1,161,484 572 17,472 1,144,584  $ 3,014,428 $ 2,427 $ 64,560 $ 2,952,295 $ 2,977,511 $ 13,110 $ 28,611 $ 2,962,010  The following table presents the amortized cost and estimated fair value of debt securities available for sale and held to maturity at March 31, 2018 by contractual maturity. Actual maturities will differ from contractual maturities because of rights to call or repay obligations with or without penalties and scheduled and unscheduled principal payments on mortgage-backed securities and collateralized mortgage obligations.       Debt Securities Available for Sale Amortized Fair  (in thousands) Cost Value  Due in one year or less $ 7,388 $ 7,408  Due after one year through five years 45,623 45,740  Due after five years through ten years 1,249,127 1,202,997  Due after ten years 1,706,813 1,659,503  Total available for sale debt securities $ 3,008,951 $ 2,915,648   Debt Securities Held to Maturity Amortized Fair  (in thousands) Cost Value  Due in one year or less $ 4,190 $ 4,205  Due after one year through five years 132,047 131,197  Due after five years through ten years 1,478,419 1,446,343  Due after ten years 1,399,772 1,370,550  Total held to maturity securities $ 3,014,428 $ 2,952,295 The Company held no securities c lassified as trading at March 31, 2018 or December 31, 2017 . The fair value and gross unrealized losses for securities classified as available for sale with unrealized losses for the periods indicated follow.     Available for Sale  March 31, 2018 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ 43,521 1,214 50,362 2,333 $ 93,883 $ 3,547  Municipal obligations 54,330 948 169,119 7,136 223,449 8,084  Residential mortgage-backed securities 654,990 14,667 850,853 32,724 1,505,843 47,391  Commercial mortgage-backed securities 279,631 8,091 400,641 26,997 680,272 35,088  Collateralized mortgage obligations 122,186 2,324 32,972 632 155,158 2,956  $ 1,154,658 $ 27,244 $ 1,503,947 $ 69,822 $ 2,658,605 $ 97,066       Available for Sale  December 31, 2017 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ 45,616 $ 42 $ 51,157 $ 2,221 $ 96,773 $ 2,263  Municipal obligations 2,768 11 173,530 3,335 176,298 3,346  Residential mortgage-backed securities 461,835 4,195 898,099 16,192 1,359,934 20,387  Commercial mortgage-backed securities 203,618 995 411,046 16,868 614,664 17,863  Collateralized mortgage obligations 128,174 1,076 35,488 483 163,662 1,559  $ 842,011 $ 6,319 $ 1,569,320 $ 39,099 $ 2,411,331 $ 45,418 The fair value and gross unrealized losses for securities classified as held to maturity with unrealized losses for the periods indicated follow.      Held to maturity  March 31, 2018 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ — — 49,424 576 $ 49,424 $ 576  Municipal obligations 341,011 4,530 221,438 8,923 562,449 13,453  Residential mortgage-backed securities 403,985 4,090 224,200 6,534 628,185 10,624  Commercial mortgage-backed securities 234,468 6,845 71,098 4,555 305,566 11,400  Collateralized mortgage obligations 672,660 12,567 441,866 15,940 1,114,526 28,507  $ 1,652,124 $ 28,032 $ 1,008,026 $ 36,528 $ 2,660,150 $ 64,560      Held to maturity  December 31, 2017 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ — $ — $ 49,711 $ 289 $ 49,711 $ 289  Municipal obligations 14,603 19 230,960 4,226 245,563 4,245  Residential mortgage-backed securities 8,815 99 230,277 2,591 239,092 2,690  Commercial mortgage-backed securities 174,882 744 72,499 3,171 247,381 3,915  Collateralized mortgage obligations 570,289 5,653 472,536 11,819 1,042,825 17,472  $ 768,589 $ 6,515 $ 1,055,983 $ 22,096 $ 1,824,572 28,611 The unrealized losses primarily relate to c hanges in market rates on fixed rate debt securities since the respective purchase dates. In all cases, the indicated impairment on these debt securities would be recovered no later than the security’s maturity date or possibly earlier if the market price for the security increases with a reduction in the yield required by the market. None of the unrealized losses relate to the marketability o f the securities or the issuers’ abilities to meet contractual obligations. The Company believes it has adequate liquidity and, therefore, does not plan to and, more likely than not, will not be required to sell these securities before recovery of the indicated impairment. Accordingly, the unrealized losses on these securities have been determined to be temporary. There were no sales of securities during either of the three months ended March 31, 2018 or 2017. Securities with carrying values totaling $ 3.4 billion and $3.3 billion at March 31, 2018 and December 31, 2017, respectively, were pledged as collateral , primarily to secure public deposits or sec urities sold under agreements to repurchase.

Loans and Allowance for Loan Lo

Loans and Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2018
Loans and Allowance for Loan Losses [Abstract]
Loans and Allowance for Loan Losses	4. Loans and Allowance for Loan Losses The Company generally makes loans in its market areas of south Mississippi, southern and central Alabama, south Louisiana, the Houston, Texas area and the northern, central and panhandle regions of Florida. Loans, net of unearned income, by portfolio are presented in the table below.     March 31, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 8,336,222 $ 8,297,937  Commercial real estate - owner occupied 2,185,543 2,142,439  Total commercial & industrial 10,521,765 10,440,376  Commercial real estate - income producing 2,394,862 2,384,599  Construction and land development 1,413,878 1,373,421  Residential mortgages 2,732,821 2,690,472  Consumer 2,029,178 2,115,295  Total loans $ 19,092,504 $ 19,004,163  The following briefly describes the composition of each loan category.  Commercial and industrial  Commercial and industrial loans are made available to businesses for working capital (including financing of inventory and receivables), business expansion, to facilitate the acquisition of a business, and the purchase of equipment and machinery, including equipment leasing. These loans are primarily made based on the identified cash flows of the borrower and, when secured, have the added strength of the underlying collateral.  Commercial non-real estate loans may be secured by the assets being financed or other tangible or intangible business assets such as accounts receivable, inventory, ownership , enterprise value or commodity interests, and may incorporate a personal or corporate guarantee; however, some short-term loans may be made on an unsecured basis, including a small portfolio of corporate credit cards, generally issued as a part of overall customer relationships.  Commercial real estate – owner occupied loans consist of commercial mortgages on properties where repayment is generally dependent on the cash flow from the ongoing operations and activities of the borrower. Like commercial non-real estate, these loans are primarily made based on the identified cash flows of the borrower, but also have the added strength of the value of underlying real estate collateral.  Commercial real estate – income producing  Commercial real estate – income producing loans consist of loans secured by commercial mortgages on properties where the loan is made to real estate developers or investors and repayment is dependent on the sale, refinance, or income generated from the operation of the property. Properties financed include retail, office, multifamily, senior housing, hotel/motel, skilled nursing facilities and other commercial properties.  Construction and land development  C onstruction and land development loans are made to facilitate t he acquisition, development, improvement and construction of both commercial and residential-purpose properties. Such loans are made to builders and investors where repayment is expected to be made from the sale, refinance or operation of the property or to businesses to be used in their business operations. This portfolio also includes a small amount of residential construction loans and loans secured by raw land not yet under development.  Residential m ortgages  Residential mortgages consist of closed-end loans secured by first liens on 1- 4 family residential properties. The portfolio includes both fixed and adjustable rate loans, although most longer term, fixed rate loans originated are sold in the secondary mortgage market .  Consumer  Consumer loans include second lien mortgage home loans, home equity lines of credit and nonresidential consumer purpose loans. Nonresidential consumer loans include both direct and indirect loans. Direct nonresidential consumer loans are made to finance the purchase of personal property, including automobiles, recreational vehicles and boats, and for other personal purposes (secured and unsecured), and deposit account secured loans. Indirect nonresidential consumer loans include automobile financing provided to the consumer through an agreement with automobile dealerships. Consumer loans also include a small portfolio of credit card receivables issued on the basis of applications received through referrals from the Bank’s branches, online and other marketing efforts. Allowance for Loan Losses The following tables show activity in the allowance for loan losses by portfolio class for the three months ended March 31, 2018 and 2017, as well as the corresponding recorded investment in loans at the end of each period. Charge-off, recovery and provision activity in the purchased credit impaired portfolio previously segregated has been collapsed into the remainder of the portfolio’s activity as it is no longer material, and the respective reclassifications have been made to the prior period to conform to the current presentation.      Commercial Commercial  Commercial real estate- Total real estate- Construction  non-real owner commercial & income and land Residential  (in thousands) estate occupied industrial producing development mortgages Consumer Total  Three Months Ended March 31, 2018  Allowance for loan losses:  Beginning balance $ 127,918 $ 12,962 $ 140,880 $ 13,709 $ 7,372 $ 24,844 $ 30,503 $ 217,308  Charge-offs (9,335) (851) (10,186) — (10) (192) (8,048) (18,436)  Recoveries 4,146 88 4,234 63 29 116 1,794 6,236  Net provision for loan losses 3,877 1,421 5,298 (787) 2,533 150 5,059 12,253  Reduction as a result of sale of subsidiary — — — — — — (6,648) (6,648)  Ending balance $ 126,606 $ 13,620 $ 140,226 $ 12,985 $ 9,924 $ 24,918 $ 22,660 $ 210,713   Allowance at end of period :  Individually evaluated for impairment $ 20,356 $ 2,475 $ 22,831 $ 1,261 $ 1 $ 276 $ 232 $ 24,601  Amounts related to purchased credit impaired loans 471 495 966 576 173 11,720 612 14,047  Collectively evaluated for impairment 105,779 10,650 116,429 11,148 9,750 12,922 21,816 172,065  Total allowance $ 126,606 $ 13,620 $ 140,226 $ 12,985 $ 9,924 $ 24,918 $ 22,660 $ 210,713  Loans at end of period :  Individually evaluated for impairment $ 323,913 $ 30,318 $ 354,231 $ 14,071 $ 113 $ 8,338 $ 617 $ 377,370  Purchased credit impaired loans 8,510 8,384 16,894 4,361 5,843 116,409 5,876 149,383  Collectively evaluated for impairment 8,003,799 2,146,841 10,150,640 2,376,430 1,407,922 2,608,074 2,022,685 18,565,751  Total loans $ 8,336,222 $ 2,185,543 $ 10,521,765 $ 2,394,862 $ 1,413,878 $ 2,732,821 $ 2,029,178 $ 19,092,504        Commercial Commercial  Commercial real estate- Total real estate- Construction  non-real owner commercial & income and land Residential  (in thousands) estate occupied industrial producing development mortgages Consumer Total  Three Months Ended March 31, 2017  Allowance for loan losses:  Beginning balance $ 147,052 $ 11,083 $ 158,135 $ 13,509 $ 6,271 $ 25,361 $ 26,142 $ 229,418  Charge-offs (24,791) (29) (24,820) (7) (91) (348) (8,678) (33,944)  Recoveries 938 275 1,213 375 471 113 1,743 3,915  Net provision for loan losses 8,101 193 8,294 (266) 69 376 7,518 15,991  Decrease in FDIC loss share receivable (31) — (31) — — (1,696) (103) (1,830)  Ending balance $ 131,269 $ 11,522 $ 142,791 $ 13,611 $ 6,720 $ 23,806 $ 26,622 $ 213,550   Allowance at end of period :  Individually evaluated for impairment $ 15,017 $ 76 $ 15,093 $ 1,114 $ 1 $ 94 $ 199 $ 16,501  Amounts related to purchased credit impaired loans 411 787 1,198 213 283 13,286 1,019 15,999  Collectively evaluated for impairment 115,841 10,659 126,500 12,284 6,436 10,426 25,404 181,050  Total allowance $ 131,269 $ 11,522 $ 142,791 $ 13,611 $ 6,720 $ 23,806 $ 26,622 $ 213,550  Loans at end of period :  Individually evaluated for impairment $ 231,988 $ 3,894 $ 235,882 $ 13,599 $ 1,592 $ 3,236 $ 2,149 $ 256,458  Purchased credit impaired loans 6,693 12,468 19,161 7,669 4,326 138,260 9,951 179,367  Collectively evaluated for impairment 7,835,606 2,031,089 9,866,695 2,483,836 1,246,749 2,124,767 2,046,996 17,769,043  Total loans $ 8,074,287 $ 2,047,451 $ 10,121,738 $ 2,505,104 $ 1,252,667 $ 2,266,263 $ 2,059,096 $ 18,204,868  Impaired Loans The following table shows the composition of nonaccrual loans by portfolio class. Purchased credit impaired loans accounted for in pools with an accretable yield are considered to be performing and are excluded from the table.     March 31, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 179,203 $ 152,863  Commercial real estate - owner occupied 27,387 25,989  Total commercial & industrial 206,590 178,852  Commercial real estate - income producing 15,633 14,574  Construction and land development 3,724 3,807  Residential mortgages 35,069 40,480  Consumer 14,163 15,087  Total loans $ 275,179 $ 252,800 Nonaccrual loans include nonaccruing loans modified in troubled debt restructurings (“TDRs”) of $ 118.0 million and $ 99.2 million at March 31, 2018 and December 31, 2017, respectively. Total TDRs, both accruing and nonaccruing, were $ 284.5 million at March 31, 2018 and $ 219.7 million at December 31, 2017. All TDRs are individually evaluated for impairment. At March 31, 2018 and December 31, 2017, the Company had unfunded commitments of $8.5 million and $7.3 million, respectively, to borrowers whose loan terms have been modified in a TDR. The table below details by portfolio class TDRs that were modified during the three months ended March 31, 2018 and 2017:      Three Months Ended  ($ in thousands) March 31, 2018 March 31, 2017  Pre-Modification Post-Modification Pre-Modification Post-Modification  Outstanding Outstanding Outstanding Outstanding  Number of Recorded Recorded Number of Recorded Recorded  Troubled Debt Restructurings: Contracts Investment Investment Contracts Investment Investment  Commercial non-real estate 13 $ 55,482 $ 55,482 9 $ 38,659 $ 38,659  Commercial real estate - owner occupied 1 5,909 5,909 1 656 656  Total commercial & industrial 14 61,391 61,391 10 39,315 39,315  Commercial real estate - income producing 1 1,564 1,564 2 5,527 5,527  Construction and land development 1 43 43 — — —  Residential mortgages — — — 1 250 250  Consumer 1 222 222 — — —  Total loans 17 $ 63,220 $ 63,220 13 $ 45,092 $ 45,092  The TDRs modified during the three months ended March 31, 2018 reflected in the table above include $ 48.4 million of loans with extended amortization terms or other payment concessions, $ 14.6 million with significant covenant waivers and $ 0.2 million with other modifications. The TDRs modified during the three months ended March 31, 2017 include $ 27.4 million of loans with extended amortization terms or other payment concessions, $ 10.7 million with significant covenant waivers and $ 6.9 million with other modifications.  For the three month periods ended March 31, 2018 and 2017, there were no loans modified in a TDR within the previous twelve months that subsequently defaulted during the respective periods. The tables below present loans that are individually evaluated for impairment disaggregated by portfolio class at March 31, 2018 and December 31, 2017. Loans individually evaluated for impairment include TDRs and loans that are determined to be impaired and have aggregate relationship balances of $1 million or more.     March 31, 2018  Recorded investment Recorded investment Unpaid  (in thousands) without an allowance with an allowance principal balance Related allowance  Commercial non-real estate $ 108,898 $ 215,015 $ 335,178 $ 20,356  Commercial real estate - owner occupied 6,064 24,254 30,997 2,475  Total commercial & industrial 114,962 239,269 366,175 22,831  Commercial real estate - income producing 6,055 8,016 14,269 1,261  Construction and land development 100 13 114 1  Residential mortgages 5,861 2,477 11,682 276  Consumer 14 603 718 232  Total loans $ 126,992 $ 250,378 $ 392,958 $ 24,601    December 31, 2017  Recorded investment Recorded investment Unpaid  (in thousands) without an allowance with an allowance principal balance Related allowance  Commercial non-real estate $ 116,682 $ 151,199 $ 285,685 $ 16,129  Commercial real estate - owner occupied 16,927 4,564 24,829 793  Total commercial & industrial 133,609 155,763 310,514 16,922  Commercial real estate - income producing 5,101 10,429 15,687 1,326  Construction and land development 100 263 363 11  Residential mortgages 8,245 2,395 13,855 189  Consumer — 1,292 1,294 118  Total loans $ 147,055 $ 170,142 $ 341,713 $ 18,566 The tables below present the average balances and interest income for total impaired loans for the three months ended March 31, 2018 and 2017. Interest income recognized represents interest on accruing loans modified in a TDR.      Three Months Ended  March 31, 2018 March 31, 2017  Average Interest Average Interest  recorded income recorded income  (in thousands) investment recognized investment recognized  Commercial non-real estate $ 295,897 $ 1,586 $ 251,625 $ 337  Commercial real estate - owner occupied 25,905 66 5,081 4  Total commercial & industrial 321,802 1,652 256,706 341  Commercial real estate - income producing 14,801 25 14,487 43  Construction and land development 238 — 1,766 —  Residential mortgages 9,489 5 3,792 2  Consumer 955 9 2,152 2  Total loans $ 347,285 $ 1,691 $ 278,903 $ 388 Aging Analysis The tables below present the age analysis of past due loans by portfolio class at March 31, 2018 and December 31, 2017. Purchased credit impaired loans accounted for in pools with an accretable yield are considered to be current.     Recorded  Greater than investment  30-59 days 60-89 days 90 days Total Total > 90 days and  March 31, 2018 past due past due past due past due Current Loans still accruing  (in thousands)  Commercial non-real estate $ 45,309 $ 18,497 $ 130,360 $ 194,166 $ 8,142,056 $ 8,336,222 $ 20,330  Commercial real estate - owner occupied 7,464 115 22,138 29,717 2,155,826 2,185,543 1,360  Total commercial & industrial 52,773 18,612 152,498 223,883 10,297,882 10,521,765 21,690  Commercial real estate - income producing 928 1,954 8,419 11,301 2,383,561 2,394,862 2,771  Construction and land development 6,537 416 3,115 10,068 1,403,810 1,413,878 259  Residential mortgages 32,815 4,496 20,122 57,433 2,675,388 2,732,821 1,170  Consumer 16,083 5,124 7,542 28,749 2,000,429 2,029,178 573  Total $ 109,136 $ 30,602 $ 191,696 $ 331,434 $ 18,761,070 $ 19,092,504 $ 26,463      Recorded  Greater than investment  30-59 days 60-89 days 90 days Total Total > 90 days and  December 31, 2017 past due past due past due past due Current Loans still accruing  (in thousands)  Commercial non-real estate $ 62,766 $ 10,761 $ 92,982 $ 166,509 $ 8,131,428 $ 8,297,937 $ 21,989  Commercial real estate - owner occupied 8,493 648 15,517 24,658 2,117,781 2,142,439 2,032  Total commercial & industrial 71,259 11,409 108,499 191,167 10,249,209 10,440,376 24,021  Commercial real estate - income producing 5,315 2,165 6,081 13,561 2,371,038 2,384,599 489  Construction and land development 4,113 1,056 3,412 8,581 1,364,840 1,373,421 477  Residential mortgages 33,621 10,554 30,537 74,712 2,615,760 2,690,472 2,208  Consumer 22,959 7,816 8,553 39,328 2,075,967 2,115,295 571  Total $ 137,267 $ 33,000 $ 157,082 $ 327,349 $ 18,676,814 $ 19,004,163 $ 27,766  Credit Quality Indicators The following tables present the credit quality indicators by segments and portfolio class of loans at March 31, 2018 and December 31, 2017.      March 31, 2018  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial & industrial Commercial real estate - income producing Construction and land development Total commercial  Grade:  Pass $ 7,250,715 $ 1,954,384 $ 9,205,099 $ 2,268,358 $ 1,334,456 $ 12,807,913  Pass-Watch 269,657 51,856 321,513 58,092 59,208 438,813  Special Mention 100,005 35,971 135,976 9,344 6,279 151,599  Substandard 715,827 143,332 859,159 59,068 13,935 932,162  Doubtful 18 — 18 — — 18  Total $ 8,336,222 $ 2,185,543 $ 10,521,765 $ 2,394,862 $ 1,413,878 $ 14,330,505   December 31, 2017  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial & industrial Commercial real estate - income producing Construction and land development Total commercial  Grade:  Pass $ 7,190,604 $ 1,896,366 $ 9,086,970 $ 2,223,245 $ 1,291,638 $ 12,601,853  Pass-Watch 293,069 82,913 375,982 83,444 60,804 520,230  Special Mention 80,649 27,456 108,105 13,244 4,788 126,137  Substandard 733,558 135,704 869,262 64,658 16,191 950,111  Doubtful 57 — 57 8 — 65  Total $ 8,297,937 $ 2,142,439 $ 10,440,376 $ 2,384,599 $ 1,373,421 $ 14,198,396       March 31, 2018 December 31, 2017  (in thousands) Residential mortgage Consumer Total Residential mortgage Consumer Total  Performing $ 2,696,582 $ 2,014,442 $ 4,711,024 $ 2,647,784 $ 2,099,637 $ 4,747,421  Nonperforming 36,239 14,736 50,975 42,688 15,658 58,346  Total $ 2,732,821 $ 2,029,178 $ 4,761,999 $ 2,690,472 $ 2,115,295 $ 4,805,767 Below are the definitions of the Company’s internally assigned grades: Commercial : · Pass – loans properly approved, documented, collateralized, and performing which do not reflect an abnormal credit risk. · Pass-Watch – credits in this category are of sufficient risk to cause concern. This category is reserved for credits that display negative performance trends. The “Watch” grade should be regarded as a transition category. · Special Mention – a criticized asset category defined as having potential weaknesses that deserve management’s close attention. If left uncorrected, these potential weaknesses may, at some future date, result in the deterioration of the repayment prospects for the credit or the institution’s credit position. Special mention credits are not considered part of the Classified credit categories and do not expose the institution to sufficient risk to warrant adverse classification. · Substandard – an asset that is inadequately protected by the current sound worth and paying capacity of the obligor or of the collateral pledged, if any. Assets so classified must have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. · Doubtful – an asset that has all the weaknesses inherent in one classified Substandard with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. · Loss – credits classified as Loss are considered uncollectable and are charged off promptly once so classified. Residential and Consumer: · Performing – loans on which payments of principal and interest are less than 90 days past due. · Nonperforming – a nonperforming loan is a loan that is in default or close to being in default and there are good reasons to doubt that payments will be made in full. All loans rated as nonaccrual loans are also classified as nonperforming.  Purchased Credit Impaired Loans Changes in the carrying amount of purchased credit impaired loans and related accretable yield are presented in the following table for the three months ended March 31, 2018 and the year ended December 31, 2017.      March 31, 2018 December 31, 2017  Carrying Carrying  Amount Accretable Amount Accretable  (in thousands) of Loans Yield of Loans Yield  Balance at beginning of period $ 153,403 $ 62,517 $ 190,915 $ 113,686  Addition of cost recovery loans - FNBC I — — 15,000 —  Payments received, net (8,288) (1,703) (69,591) (7,412)  Accretion 4,268 (4,268) 17,079 (17,079)  Increase in expected cash flows based on actual cash flows and changes in cash flow assumptions — (956) — (30,379)  Net transfers from nonaccretable difference to accretable yield — — — 3,701  Balance at end of period $ 149,383 $ 55,590 $ 153,403 $ 62,517  During the three months ended March 31, 2017, certain of the Company’s purchased credit impaired loans were covered by two loss share agreements with the FDIC. The Company had a receivable representing an indemnification asset arising from the agreements. The receivable was accounted for separately from the covered loans as the agreements were not contractually part of the loans and were not transferrable should the Company have disposed of the loans. The agreements were terminated by the Company during the third quarter of 2017.   Residential Mortgage Loans in Process of Foreclosure  Included in loans are $ 7.8 million and $ 7.5 million of consumer loans secured by single family residential real estate that are in process of foreclosure as of March 31, 2018 and December 31, 2017, respectively. Loans in process of foreclosure include those for which formal foreclosure proceedings are in process according to local requirements of the applicable jurisdiction. In addition to the single family residential real estate loans in process of foreclosure, the Company also held $ 3.7 million and $3. 4 million of foreclosed single family residential properties in other real estate owned as of March 31, 2018 and December 31, 2017, respectively.

Securities Sold under Agreement

Securities Sold under Agreements to Repurchase	3 Months Ended
	Mar. 31, 2018
Securities Sold under Agreements to Repurchase [Abstract]
Securities Sold under Agreements to Repurchase	5. Securities Sold under Agreements to Repurchase Included in short-term borrowings are customer securities sold under agreements to repurchase (“repurchase agreements”) that mature daily and are secured by U.S. agency securities totaling $ 443.2 million and $430.6 million at March 31, 2018 and December 31, 2017, respectively . The Company borrows funds on a secured basis by selling securities under agreements to repurchase, mainly in connection with treasury management services offered to its deposit customers. As the Company maintains effective control over assets sold under agreements to repurchase, the securities continue to be carried on the consolidated statements of financial condition. Because the Company acts as borrower transferring assets to the counterparty, and the agreements mature daily, the Company’s risk is limited.

Derivatives

Derivatives	3 Months Ended
	Mar. 31, 2018
Derivatives [Abstract]
Derivatives	6. Derivatives On January 1, 2018, the Company adopted the provisions of Accounting Standards Update (ASU) 2017-12, “Derivatives and Hedging,” using the modified retrospective transition approach . As a result of adoption of the u pdate, the Company is making certain adjustments to its existing designation documentation for active hedging relationships to take advantage of sp ecific provisions of the update. Adoption of this guidance did not have a material impact on the Company’s financial condition or results of operations. Following is a discussion of the provisions of the guidance relevant to the Company: Ineffectiveness measurement and presentation The provisions of the update eliminate the concept of ineffectiveness from an accounting perspective. The guidance provides that, as long as a hedging instrument is designated and the results of the effectiveness testing support that the instrument qualifies for hedge accounting treatment, there will be no periodic measurement or recognition of ineffectiveness. Rather, the full impact of hedge gains and losses will be recognized in the period in which the hedged transactions impact the entity’s earnings. Presentation of r eclassifications from Accumulated Other Comprehensive Income Amounts in Accumulated Other Comprehensive Income that are included in the assessment of effectiveness should be reclassified into earnings in the same period in which the hedged forecasted transactions impact earnings. As such, the Company will recognize all reclassifications out of Other Comprehensive Income in the same statement of income line item in which the earnings effect of the hedged item is presented. Changes to hedged risk The update also states that if the designated hedged risk changes during the life of the hedging relationship, an entity may continue to apply hedge accounting as long as the hedging instrument is highly effective at achieving offsetting cash flows attributable to the revised hedged risk. Regardless of the description of the hedged transactions contained in the initial designation documentation, the Company intends to utilize this provision in the updated guidance to the extent possible. Risk component hedging in fair value hedges The update allows an entity to make a one-time transition election regarding the fair value measurement methodology applied to fair value hedges in place at adoption. The Company did not elect either of the one-time transition options; rather, it will continue to measure the hedged items as documented in the initial hedge documentation. Risk Management Objective of Using Derivatives The Company enters into derivative financial instruments to manage risks related to differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments, currently related to select pools of variable rate loans and fixed rate brokered deposits. The Bank also enters into interest rate derivative agreements as a service to certain qualifying customers. The Bank manages a matched book with respect to these customer derivatives in order to minimize its net risk exposure resulting from such agreements. The Bank also enters into risk participation agreements under which it may either sell or buy credit risk associated with a customer’s performance under certain interest rate derivative contracts related to loans in which participation interests have been sold to or purchased from other banks. Fair Values of Derivative Instruments on the Balance Sheet The table below presents the notional or contractual amounts and fair values of the Company’s derivative financial instruments as well as their classification on the consolidated balance sheets as of March 31, 2018 and December 31, 2017.      March 31, 2018 December 31, 2017  Derivative (1) Derivative (1)  (in thousands) Type of Hedge Notional or Contractual Amount Assets Liabilities Notional or Contractual Amount Assets Liabilities  Derivatives designated as hedging instruments:  Interest rate swaps Cash Flow $ 875,000 $ 1,752 $ 12,667 $ 875,000 $ — $ 14,020  Interest rate swaps Fair Value 483,110 — 3,948 483,110 — 2,475  $ 1,358,110 $ 1,752 $ 16,615 $ 1,358,110 $ — $ 16,495  Derivatives not designated as hedging instruments:  Interest rate swaps (2) N/A $ 1,184,109 $ 20,680 $ 20,710 $ 1,144,789 $ 15,408 $ 15,857  Risk participation agreements N/A 121,479 13 61 119,951 23 109  Forward commitments to sell residential mortgage loans N/A 81,326 847 454 80,462 1,000 290  Interest rate-lock commitments on residential mortgage loans N/A 61,904 376 789 53,724 186 782  Foreign exchange forward contracts N/A 42,815 3,096 3,062 42,260 2,453 2,419  1,491,633 25,012 25,076 1,441,186 19,070 19,457  Total derivatives $ 2,849,743 $ 26,764 $ 41,691 $ 2,799,296 $ 19,070 $ 35,952  Less: netting adjustment (3) (14,081) (19,162) (4,913) (21,563)  Total derivative assets/liabilities $ 12,683 $ 22,529 $ 14,157 $ 14,389 (1) Derivative assets and liabilities are reported at fair value in other assets or other liabilities, respectively, in the consolidated balance sheets. (2) The notional amount represents both the customer accommodation agreements and offsetting agreements with unrelated financial institutions.  (3) Represents balance sheet netting of derivative assets and liabilities for variation margin collateral held or placed with the same central clearing counterparty. See offsetting assets and liabilities for further information.  Cash Flow Hedges of Interest Rate Risk The Company is party to various interest rate swap agreements designated and qualify ing as cash flow hedges of the Company’s forec asted variable cash flows for pools of variable rate loans. For each agreement, the Company receives interest at a fixed rate and pays at a variable rate. During the three months ended March 31, 2018, the Company terminated five of its shorter-term swap agreements with notional amounts totaling $450 million and entered into five longer-term agreements with notional amounts totaling $450 million. The Company paid termination fees of approximately $10.6 million to settle the interest rate swap liabilities, and the resulting accumulated other comprehensive loss will be amortized over the remaining maturities of the designated instruments. Amortization of other comprehensive loss on terminated cash flow hedges totaled $1.0 million for the three months ended March 31, 2018. The notional amounts of the swap agreements in place at March 31, 2018 expire as follows: $ 425 million in 20 22 ; $ 350 million in 202 3 ; and $ 100 million in 202 4 .  Fair Value Hedges of Interest Rate Risk  During 2017, the Company entered into interest rate swap agreements that modify the Company’s exposure to interest rate risk by effectively converting a portion of the Company’s brokered certificates of deposit from fixed rates to variable rates. The maturities and call features of these interest rate swaps match the features of the hedged deposits. As interest rates fall, the decline in the value of the certificates of deposit is offset by the increase in the value of the interest rate swaps. Conversely, as interest rates rise, the value of the underlying hedged deposits increases, but the value of the interest rate swaps decrease s , resu lting in no impact on earnings. Interest expense is adjusted by the difference between the fixed and floating rates for the period the swaps are in effect. Derivatives Not Designated as Hedges Customer interest rate derivative program The Bank enters into interest rate derivative agreements, primarily rate swaps, with commercial banking customers to facilitate their risk management strategies. The Bank enters into offsetting agreements with unrelated financial institutions, thereby mitigating its net risk exposure resulting from such transactions. Because the interest rate derivatives associated with this program do not meet hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings. Risk participation agreements The Bank also enters into risk participation agreements under which it may either assume or sell credit risk associated with a borrower’s performance under certain interest rate derivative contracts. In those instances where the Bank has assumed credit risk, it is not a direct counterparty to the derivative contract with the borrower and has entered into the risk participation agreement because it is a party to the related loan agreement with the borrower. In those instances in which the Bank has sold credit risk, it is the sole counterparty to the derivative contract with the borrower and has entered into the risk participation agreement because other banks participate in the related loan ag reement. The Bank manages its credit risk under risk participation agreements by monitoring the creditworthine ss of the borrower, based on the Bank’s normal credit review process. Mortgage banking derivatives The Bank also enters into certain deri vative agreements as part of its mortgage banking activities. These agreements include interest rate lock commitments on prospective residential mortgage loans and forward commitments to sell these loans to investors on a best efforts delivery basis. Customer foreign exchange forward contract derivatives The Bank enters into foreign exchange forward derivative agreements, primarily forward foreign currency contracts, with commercial ban king customers to facilitate their risk management strategies. The Bank manages its risk exposure from such transactions by entering into offsetting agreements with unrelated financial institutions. Because the foreign exchange forward contract derivatives associated with this program do not meet hedge accounting requirements, changes in the fair value of both the customer derivatives and the offsetting derivatives are recognized directly in earnings. Effect of Derivative Instruments on the Income Statement  Derivative instrument income consisting primarily of customer interest rate swap fees, net of fair value adjustments, is reflected in the income statement in other noninterest income, totaling $ 1.5 million and $ 0.5 million for the three months ended March 31, 2018 and 2017 , respectively . The impact to interest income from cash flow hedges, including amortization of comprehensive loss on terminated cash flow hedges, was $(0.6) million and $0. 1 million for the three months ended March 31, 2018 and 2017, respectively. Interest expense as a result of mark to market adjustments of fair value hedges was $0.1 million and $(0.1) million for the three months ended March 31, 2018 and 2017. Credit Risk-R elated Contingent Features Certain of the Bank’s derivative instruments contain provisions allowing the financial institution counterparty to terminate the contracts in ce rtain circumstances, such as a downgrade of the Bank’s credit ratings below specified levels, a default by the Bank on its indebtedness, or the failure of the Bank to maintain specified minimum regulatory capital ratios or its regulatory status as a well-capitalized institution. These derivative agreements also contain provisions regarding the posting of collateral by each party. Offsetting Assets and Liabilities The Bank’s derivative instruments with certain counterparties contain legally enforceable netting provisions that allow for net settlement of multiple transactions to a single amount, which may be positive, negative, or zero. Agreements with certain bilateral counterparties require both parties to maintain collateral in the event that the fair values of derivative instruments exceed established exposure thresholds. For centrally cleared derivatives, the Company is subject to initial margin posting and daily variation margin exchange with the central clearinghouses. Offsetting information in regards to all derivative assets and liabilities , including accrued interest, subject to these master netting agreements at March 31, 2018 and December 31, 2017 is presented in the following tables.      (in thousands) Gross Amounts Net Amounts Gross Amounts Not Offset in the Statement of Income  Description Gross Amounts Recognized Offset in the Statement of Income Presented in the Statement of Income Financial Instruments Cash Collateral Net Amount  As of March 31, 2018  Derivative Assets $ 18,822 $ (14,314) $ 4,508 $ 1,517 $ — $ 2,991   Derivative Liabilities $ 18,081 $ (16,497) $ 1,584 $ 1,517 $ 4,770 $ (4,703)      (in thousands) Gross Amounts Net Amounts Gross Amounts Not Offset in the Statement of Income  Description Gross Amounts Recognized Offset in the Statement of Income Presented in the Statement of Income Financial Instruments Cash Collateral Net Amount  As of December 31, 2017  Derivative Assets $ 7,155 $ (5,007) $ 2,148 $ 2,148 $ — $ —   Derivative Liabilities $ 24,015 $ (20,077) $ 3,938 $ 2,148 $ 4,099 $ (2,309)  The Company has excess collateral compared to total exposure due to initial margin requirements for day-to-day rate volatility.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity [Abstract]
Stockholders' Equity	 7 . Stockholders’ Equity  Common Shares Outstanding  Common shares outstanding excludes treasury shares totaling 1.1 million and 1.2 million at March 31, 2018 and December 31, 2017 , respectively, with a first-in-first-out cost basi s of $24.4 million and $25.5 m illion at March 31, 2018 and December 31, 2017 , respectively. Shares outstanding also exclude s unvested restricted share awards totaling 1. 5 million at March 31, 2018 and December 31, 2017. A ccumulated Other Comprehensive Income (Loss) T he components of Accumulated Other Comprehensive Loss and changes in those components are presented in the following table.     Available HTM Securities  for Sale Transferred Employee Cash  (in thousands) Securities from AFS Benefit Plans Flow Hedges Total  Balance, December 31, 2016 $ (28,679) $ (14,392) $ (72,501) $ (4,960) $ (120,532)  Other comprehensive income (loss) before income taxes:  Net change in unrealized gain 2,319 — — (1,135) 1,184  Reclassification of net (gain) loss realized and included in earnings — — 1,387 — 1,387  Amortization of unrealized net loss on securities transferred to HTM — 650 — — 650  Income tax expense (benefit) 843 266 504 (412) 1,201  Balance, March 31, 2017 $ (27,203) $ (14,008) $ (71,618) $ (5,683) $ (118,512)  Balance, December 31, 2017 $ (29,512) $ (14,585) $ (79,078) $ (11,227) $ (134,402)  Other comprehensive income (loss) before income taxes:  Net change in unrealized gain (loss) (55,114) — — (7,130) (62,244)  Reclassification of net losses realized and included in earnings — — 1,177 619 1,796  Other valuation adjustments for employee benefit plan — — — —  Amortization of unrealized net loss on securities transferred to HTM — 755 — — 755  Income tax expense (benefit) (12,508) 171 267 (1,476) (13,546)  Balance, March 31, 2018 $ (72,118) $ (14,001) $ (78,168) $ (16,262) $ (180,549) AOCI is reported as a component of stockholders’ equity. AOCI can include, among other items, unrealized holding gains and losses on securities available for sale (“AFS”), gains and losses associa ted with pension or other post- retirement benefits that are not recognized immediately as a component of net periodic benefit cost, and gains and losses on derivative instruments that are designated as, and qualify as, cash flow hedges. Net unrealized gains/losses on AFS securities reclassified as securities held to maturity (“HTM”) also continue to be reported as a component of AOCI and will be amortized over the estimated remaining life of the securities as an adjustment to interest income. Subject to certain thresholds, unrealized losses on employee benefit plans will be reclassified into income as pension and post-retirement costs are recognized over the remaining service period of plan participants. Accumulated gains/losses on the cash flow hedge of the variable rate loans described in Note 6 will be reclassified into inco me over the life of the hedge. Accumulated other comprehensive loss resulting from the terminated interest rate swaps will be amortized over the remaining maturities of the designated instruments. Gains (losses) in AOCI are net of deferred income taxes. The following table shows the line items of the consolidated statements of income affected by amounts reclassified from AOCI .      Three Months Ended  Amount reclassified from AOCI (a) March 31, Affected line item on  (in thousands) 2018 2017 the statement of income  Amortization of unrealized net loss on securities transferred to HTM (755) (650) Interest income  Tax effect 171 266 Income taxes  Net of tax (584) (384) Net income  Amortization of defined benefit pension and post-retirement items (1,177) (1,387) Other noninterest expense (b)  Tax effect 267 504 Income taxes  Net of tax (910) (883) Net income  Reclassification of unrealized gain on cash flow hedges 336 — Interest income  Tax effect (76) — Income taxes  Net of tax 260 Net income  Amortization of loss on terminated cash flow hedges (954) — Interest income  Tax effect 216 — Income taxes  Net of tax (738) — Net income  Total reclassifications, net of tax $ (1,972) $ (1,267) Net income (a) Amounts in parenthesis indicate reduction in net income.  (b) These AOCI components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 1 2 – Retirement Plans for additional details).

Revenue Recognition

Revenue Recognition	3 Months Ended
	Mar. 31, 2018
Revenue Recognition [Abstract]
Revenue Recognition	8. Revenue Recognition  Effective January 1, 2018, the Company adopted the amended provisions of the Financial Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers,” using the modified retrospective approach. The standard applies to most of the Company’s noninterest income, with a significant portion of the Company’s revenue excluded from the scope of the standard, including interest and loan origination fees associated with financial instruments, gains and losses on investment securities, derivatives and sales of financial instruments.  The Company’s evaluation of contracts for compliance with the standard did not identify any material changes to the timing of revenue recognition as the standard was largely consistent with the existing guidance and current practices . Therefore, the adoption of this guidance did not have a material impact on the Company’s financial condition or results of operations and there was no cumulative effect adjustment to opening retained earnings. However, upon adoption the Company has begun presenting certain underwriting costs (previously offset against Investment and Annuity Fees), as well as certain subadvisor costs (previously offset against Trust Fees) gross as noninterest expense, neither of which are material to operating results.  Due to the nature of the Company’s primary sources of revenue , there are no significant receivables, contract assets or contract liabilities not otherwise disclosed. The Company has assessed that its current disclosures are consistent with the requirements of the standard to present revenue disaggregated in to categories that depict how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The following provides additional qualitative disclosures about the Company’s noninterest income and revenue recognition policies.  Service Charges on Deposit Accounts Service charges on deposit accounts include transaction based fees for non-sufficient funds , account analysis fees, and other service charges on deposits, including monthly account service fees. Non-sufficient funds fees are recognized at the time when the account overdraft occurs in accordance with regulatory guidelines. Account analysis fees consist of fees charged on certain business deposit accounts based upon account activity as well as other monthly account fees, are recorded under the accrual method of accounting as services are performed.  Other service charges are earned by providing depositors safeguard and remittance of funds as well as by providing other elective services for depositors that are performed upon the depositor’s request. Charges for deposit services for the safeguard and remittance of funds are recognized at the end of the statement cycle, after services are provided , as the customer retains funds in the account. Revenue for other elective services is earned at the point in time the customer uses the service.  Trust Fees Trust fee income represents revenue generated from asset management services provided to individuals, businesses, and institutions. The Company has a fiduciary responsibility to the beneficiary of the trust to perform agreed upon services which can include investing assets, periodic reporting, and providing tax information regarding the trust. In exchange for these trust and custodial services, the Company collects fee income from beneficiaries as contractually determined via fee schedules. The Company’s performance obligation is primarily satisfied over time as the services are performed and provided to the customer. These fees are recorded under the accrual method of accounting as the services are performed. The Company generally acts as the principal in these transactions and records revenue and expenses on a gross basis.  Bank Card and Automated Teller Machine (“ATM”) Fees Bank card and ATM fees include credit card, debit card and ATM transaction revenue. The majority of this revenue is card interchange fees earned through a third party network. Performance obligations are satisfied for each transaction when the card is used and the funds are remitted. The network establishes interchange fees that the merchant remits for each transaction, and costs are incurred from the network for facilitating the interchange with the merchant. Card fees also include merchant services fees earned for providing merchants with card processing capabilities.  ATM income is generated from allowing customers to withdraw funds from other banks’ machines and from allowing a non-customer cardholder to withdraw funds from the Company’s machines. The Company satisfies its performance obligations for each transaction at the point in time that the withdrawal is processed.  Bank card and ATM fee income is recorded on accrual basis as services are provided with the related expense reflected in data processing expense.  Investment and Annuity Fees and Insurance Commissions Investment and annuity services fee income represents income earned from investment and advisory services. The Company provides its customers with access to investment products through the use of third party carriers to meet their financial needs and investment objectives. Upon selection of an investment product, the customer enters into a policy with the carrier. The performance obligation is satisfied by fulfilling its responsibility to acquire the investment for which a commission fee is earned from the carrier based on agreed-upon fee percentages on a trade date basis. The Company has a contractual relationship with a third party broker dealer to provide full service brokerage and investment advisory activities. As the agent in the arrangement, the Company recognizes the investment services commissions on a net basis. Investment revenue also includes portfolio management fees, which represent monthly fees charged on a contractual basis to customers for the management of their investment portfolios and are recorded under the accrual method of accounting on a gross basis, with expenses recorded in the appropriate expense line item.  This revenue line item includes investment banking income, which includes fees for services arising from securities offerings or placements in which the Company acts as a principal. Revenue is recognized at the time the underwriting is completed and the revenue is reasonably determinable.  Insurance commission revenue is recognized, net of cost, as of the effective date of the insurance policy as the Company’s performance obligation is connecting the customer to the insurance products. The Company also receives contingent commissions from insurance companies as additional incentive for achieving specified premium volume goals and/or the loss experience of the insurance placed. Contingent commissions from insurance companies are recognized when determinable, which is generally when such commissions are received or when we receive data from the insurance companies that allows the reasonable estimation of these amounts.  Secondary Mortgage Market Operations Secondary mortgage market operations revenue is primarily comprised of service release premiums earned on the sale of closed-end mortgage loans to other financial institutions or government agencies that are recognized in revenue as each sales transaction occurs.  Income from Bank-Owned Life Insurance Bank-owned life insurance income primarily represents income earned from the appreciation of cash surrender value of insurance contracts held and the proceeds of insurance benefits. Revenue from the proceeds of insurance benefits is recognized at the time a claim is confirmed.  Credit Related Fee Income Credit-related fee income includes letters of credit fees and unused commercial commitment fees. Revenue for letters of credit fees is recognized over time. Revenue for unused commercial commitment fees are recognized based on contractual terms, generally when collected.  Income from Derivatives Income from derivatives consists primarily of interest rate swap fees, net of fair value adjustments for customer derivatives and the related offsetting agreements with unrelated financial institutions for which the derivative instruments are not designated as hedges. This line item also includes the resulting gain or loss from ineffectiveness on derivatives that are designated as hedged items.  Gain (Loss) on Sales of Assets Gain (loss) on sales of assets reflects the excess (deficiency) of proceeds received over the carrying amount assets sold plus cost to sell for various assets other than foreclosed real estate. Gain or loss on the sale of assets are recognized as each transaction occurs.  Other Miscellaneous Income Other miscellaneous income represents a variety of revenue streams, including safe deposit box income, wire transfer fees, syndication fees and any other income not reflected above. Income is recorded once the performance obligation is satisfied, generally on the accrual basis or on a cash basis if not material and/or considered constrained. 

Other Noninterest Income

Other Noninterest Income	3 Months Ended
	Mar. 31, 2018
Other Noninterest Income [Abstract]
Other Noninterest Income	9 . Other Noninterest Income Components of other no ninterest income are as follows:       Three Months Ended  March 31,  (in thousands) 2018 2017  Income from bank-owned life insurance $ 3,070 $ 2,652  Credit related fees 2,722 2,878  Income from derivatives 1,523 465  Gain (loss) on sales of assets (1,207) 4,125  Amortization of FDIC loss share receivable — (1,100)  Other miscellaneous 3,377 2,755  Total other noninterest income $ 9,485 $ 11,775    

Other Noninterest Expense

Other Noninterest Expense	3 Months Ended
	Mar. 31, 2018
Other Noninterest Expense [Abstract]
Other Noninterest Expense	10 . Other Noninterest Expense Components of other non interest expense are as follows:    Three Months Ended  March 31,  (in thousands) 2018 2017  Advertising $ 2,526 $ 3,077  Corporate value and franchise taxes 3,440 3,036  Printing and supplies 1,286 1,178  Travel expense 1,066 1,059  Entertainment and contributions 2,518 1,783  Tax credit investment amortization 874 1,212  Other retirement expense (4,463) (3,060)  Other miscellaneous 5,684 7,285  Total other noninterest expense $ 12,931 $ 15,570 

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	11 . Earnings Per Share The Company calculates earnings per share using the two-class method. The two-class method allocates net income to each class of common stock and participating security according to common dividends declared and participation rights in undistributed earnings. Participating secur ities consist of nonvested share- based payment awards that contain nonforfeitable rights to dividends or dividend equivalents. A summary of the information used in the computation of earnings per common share follows.     Three Months Ended  March 31,  (in thousands, except per share data) 2018 2017  Numerator:  Net income to common shareholders $ 72,475 $ 49,014  Net income allocated to participating securities - basic and diluted 1,366 1,156  Net income allocated to common shareholders - basic and diluted $ 71,109 $ 47,858  Denominator:  Weighted-average common shares - basic $ 85,241 $ 84,365  Dilutive potential common shares 182 259  Weighted-average common shares - diluted $ 85,423 $ 84,624  Earnings per common share:  Basic $ 0.83 $ 0.57  Diluted $ 0.83 $ 0.57  Potential common shares consist of stock options, nonvested performance - based awards, and nonvested restricted share awards deferred under the Company’s nonqualified deferred compensation plan. These potential co mmon shares do not enter into the calculation of diluted earnings per share if the impact would be anti-dilutive, i.e., increase earnings per share or redu ce a loss per share. There were no anti-dilutive potential common shares excluded from the calculation of diluted earnings per share for the three months ended March 31, 2018. Weighted average anti-dilutive potential common shares totaled 15,986 for the three months ended March 31, 2017.

Retirement Plans

Retirement Plans	3 Months Ended
	Mar. 31, 2018
Retirement Plans [Abstract]
Retirement Plans	12. Retirement Plans  The Company sponsors a qualified defined benefit pension plan, the Hancock Holding Company Pension Plan and Trust Agreement (“Pension Plan”), covering certain eligible associates. Eligibility is based on minimum age and service-related requirements. During the second quarter of 2017, the Pension Plan was amended to exclude any individual hired or rehired by the Company after June 30, 2017 from eligibility to participate. The Pension Plan amendment further provided that the accrued benefits of each participant in the Pension Plan whose combined age plus years of service as of January 1, 2018 totals less than 55 were to be frozen as of January 1, 2018 and therefore not increase. The Company makes contributions to the Pension Plan in amounts sufficient to meet funding requirements set forth in federal employee benefit and tax laws, plus such additional amounts as the Company may determine to be appropriate. The Company was not required to make a contribution to the Pension Plan in 2017, and does not anticipate making a contribution in 2018.  The Company also offers a defined contribution retirement benefit plan (401(k) plan), the Hancock Holding Company 401(k) Savings Plan and Trust Agreement (“401(k) Plan”), that covers substantially all associates who have been employed 60 days and meet a minimum age requirement and employment classification criteria. The Company matches 100% of the first 1% of compensation saved by a participant, and 50% of the next 5% of compensation saved. Newly eligible associates are automatically enrolled at an initial 3% savings rate unless the associate actively opts out of participation in the plan. The 401(k) Plan was also amended during the second quarter of 2017 for participants whose benefits are frozen under the Pension Plan to add an enhanced Company contribution beginning January 1, 2018, in the amount of 2% , 4% or 6% of such participant’s eligible compensation, based on the participant’s age and years of service with the Company. The 401(k) Plan’s amendment further provides that the Company will contribute to the benefit of those associates of the Company hired or rehired after June 30, 2017 and those associates of the Company never enrolled in the Pension Plan an additional basic contribution in an amount equal to 2% of the associate’s eligible compensation beginning January 1, 2018. Participants will vest in the new basic and enhanced Company contributions upon completion of three years of service.  The Company sponsors a nonqualified defined benefit plan covering certain legacy Whitney employees that was frozen as of December 31, 2012 and no future benefits are accrued under this plan . The Company sponsors defined benefit postretirement plans for both legacy Hancock and legacy Whitney employees that provide health care and life insurance benefits. Benefits under the Hancock plan are not available to employees hired on or after January 1, 2000. Benefits under the Whitney plan are restricted to retirees who were already receiving benefits at the time of plan amendments in 2007 or active participants who were eligible to receive benefits as of December 31, 2007. The following tables show the components of net periodic benefits cost included in expense for the plans for the periods indicated.       Other Post-  (in thousands) Pension Benefits Retirement Benefits  Three months Ended March 31, 2018 2017 2018 2017  Service cost $ 2,925 $ 3,750 $ 35 $ 48  Interest cost 3,923 4,123 137 180  Expected return on plan assets (9,700) (8,750) — —  Amortization of net loss and prior service costs 1,326 1,435 (149) (48)  Net periodic benefit cost (reduction of cost) $ (1,526) $ 558 $ 23 $ 180 Effective January 1, 2018, the Company adopted ASU 2017-07, “Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Costs.” In accordance with the Update, only the service component of net periodic benefit cost is included in the Employee Benefits line item on the Company’s Consolidated Statement s of Income. All other components have been included in Other Noninterest Expense. Prior period amounts have been reclassified to conform to current presentation. 

Share-Based Payment Arrangement

Share-Based Payment Arrangements	3 Months Ended
	Mar. 31, 2018
Share-Based Payment Arrangements [Abstract]
Share-Based Payment Arrangements	13 . Share-Based Payment Arrangements Hancock maintains incentive compensation plans that provide for awards of share-based compensation to employees and directors. These plans have been approved by the Company’s shareholders. Detailed descriptions of these plans were included in Note 17 to the consolidated financial statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . A summary of stock option activity for the three months ended March 31, 2018 is presented below:    Weighted  Average  Weighted Remaining  Average Contractual Aggregate  Number of Exercise Term Intrinsic  Options Shares Price (Years) Value ($000)  Outstanding at January 1, 2018 88,301 $ 34.84 2.8 $ 1,294  Exercised/Released (24,793) 35.12 495  Cancelled/Forfeited — — —  Expired — — —  Outstanding at March 31, 2018 63,508 $ 34.73 2.6 $ 1,078  Exercisable at March 31, 2018 63,508 $ 34.73 2.6 $ 1,078  The total intrins ic value of options exercised for the three months ended March 31, 2018 and 2017 was $ 0.5 million and $3.3 million, respectively. The Company’s restricted and performance-based share awards to certain employees and directors are subject to service requirements . A summary of the status of the Company’s nonvested restricted and performance -based share awards as of March 31, 2018 and changes during the three months ended March 31, 2018 , is presented in the following table.    Weighted  Average  Number of Grant Date  Shares Fair Value  Nonvested at January 1, 2018 1,708,942 $ 37.05  Granted 54,710 48.22  Vested (9,587) 35.90  Forfeited (30,376) 35.25  Nonvested at March 31, 2018 1,723,689 $ 37.44  As of March 31, 2018 , there was $ 47.5 million of total unrecognized compensation expense related to nonvested restricted and performance shares expected to vest. This compensation is expected to be recognized in expense over a weighted average period of 3.3 years. T he total fair value of shares which vested during three months ended March 31, 2018 and 2017 was $0.3 million and $0.5 million , respectively. During the three months ended March 31, 2018, the Company granted 2 6,147 performance share awards subject to a total shareholder return (“TSR”) performance metric with a grant date fair value of $ 51.13 per share and 2 6,147 performance shares subject to an operating earnings per share performance metric with a grant date fair value of $ 44.84 per share to key members of executive management. The number of performance shares subject to TSR that ultimately vest at the end of the three -year performance period, if any, will be based on the relative rank of the Company’s three-year TSR among the TSRs of a peer group of 4 3 regional banks. The fair value of the performance shares subject to TSR at the grant date was determined using a Monte Carlo simulation method. The number of performance shares subject to core earnings per share that ultimately vest will be based on the Company’s attainment of certain core earnings per share goals over the two -year performance period. The maximum number of performance shares that could vest is 200% of the target award. Compensation expense for these performance shares is recognized on a straight line basis over the three -year service period.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Measurements [Abstract]
Fair Value Measurements	14 . Fair Value Measurements The Financial Accounting Standards Board (“FASB”) defines fair value as the exchange price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market partici pants on the measurement date. The FASB’s guid ance also establishes a fair value hierarchy that prioritizes the inputs to these valuation techniques used to measure fair value, giving preference to quoted prices in active markets for identical assets or liabilities (“level 1”) and the lowest priority to unobservable inputs such as a reporting entity’s own data (“level 3”). Level 2 inputs include quoted prices for similar assets or liabilities in active markets, quoted prices for identical assets or liabilities in markets that are not active, observable inputs other than quoted prices, such as interest rates and yield curves, and inputs that are derived principally from or corroborated by observable market data by correlation or other means. Fair Value of Assets and Liabilities Measured on a Recurring Basis The following tables present for each of the fair value hierarchy levels the Company’s assets and liabilities that are measured at fair value on a recurring basis in the consolidated balance sheets.     March 31, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Assets  Available for sale debt securities:  U.S. Treasury and government agency securities $ — $ 93,884 $ — $ 93,884  Municipal obligations — 237,291 — 237,291  Corporate debt securities — 5,500 — 5,500  Residential mortgage-backed securities — 1,743,543 — 1,743,543  Commercial mortgage-backed securities — 680,272 — 680,272  Collateralized mortgage obligations — 155,158 — 155,158  Total available for sale securities — 2,915,648 — 2,915,648  Derivative assets (1) — 12,682 — 12,682  Total recurring fair value measurements - assets $ — $ 2,928,330 $ — $ 2,928,330  Liabilities  Derivative liabilities (1) $ — $ 22,529 $ — $ 22,529  Total recurring fair value measurements - liabilities $ — $ 22,529 $ — $ 22,529      December 31, 2017  (in thousands) Level 1 Level 2 Level 3 Total  Assets  Available for sale debt securities:  U.S. Treasury and government agency securities $ — $ 97,272 $ — $ 97,272  Municipal obligations — 243,786 — 243,786  Corporate debt securities — 3,500 — 3,500  Residential mortgage-backed securities — 1,715,213 — 1,715,213  Commercial mortgage-backed securities — 687,135 — 687,135  Collateralized mortgage obligations — 163,963 — 163,963  Total available for sale securities — 2,910,869 — 2,910,869  Derivative assets (1) — 14,157 — 14,157  Total recurring fair value measurements - assets $ — $ 2,925,026 $ — $ 2,925,026  Liabilities  Derivative liabilities (1) $ — $ 14,389 $ — $ 14,389  Total recurring fair value measurements - liabilities $ — $ 14,389 $ — $ 14,389  (1) For further disaggregation of derivative assets and liabilities, see Note 6 - Derivatives. Securities classified as level 2 include obligations of U.S. Government agencies and U.S. Government-sponsored agencies, residential mortgage-backed securities and collateralized mortgage obligations that are issued or guaranteed by U.S. government agencies, and state and munic ipal bonds. The level 2 fair value measurements for investment securities are obtained quarterly from a third-party pricing service that uses industry-standard pricing models. Substantially all of the model inputs are observable in the marketplace or can be supported by observable data. The Company invests only in securities of investment grade quality with a targeted duration, for the overall portfolio, generally between two and five years . Company policies generally limit investments to U.S. agency securities and municipal securities determined to be investment grade according to an internally generated score which generally includes a rating of not less than “Baa” or its equivalent by a nationally recognized statistical rating agency. The fair value of derivative financial instruments, which are predominantly customer interest rate swaps, is obtained from a third-party pricing service that uses an industry-standard discounted cash flow model that relies on inputs, LIBOR swap curves and Overnight Index swap rate curves, observable in the marketplace. To comply with the accounting guidance, credit valuation adjustments are incorporated in the fair values to appropriately reflect nonperformance risk for both the Company and the counterparties. Although the Company has determined that the majority of the inputs used to value the derivative instruments fall within level 2 of the fair value hierarchy, the credit value adjustments utilize level 3 inputs, such as estimates of current credit spreads. The Company has determined that the impact of the credit valuation adjustments is not significant to the overall valuation of these derivatives. As a result, the Company has classified its derivative valuations in their entirety in level 2 of the fair value hierarchy. The Company’s policy is to measure counterparty credit risk quarterly for all derivative instruments, including those subject to master netting arrangements consistent with how market participants would price the net risk exposure at the measurement date. The Company also has certain derivative instruments asso ciated with the Bank’s mortgage banking activities. These derivative instruments include interest rate lock commitments on prospective residential mortgage loans and forward commitments to sell these loans to investors on a best efforts delivery basis. The fair value of these derivative instruments is measured using observable market prices for similar instruments and is classified as a level 2 measurement. The Company’s policy is to recognize transfers between valuation hierarchy levels as of the end of a reporting period. There were no transfers between levels during the periods presented . Fair Value of Assets Measured on a Nonrecurring Basis Certain assets and liabilities are measured at fair value on a nonrecurring basis. Collateral-dependent impaired loans are level 2 assets measured at the fair value of the underlying collateral based on independent third-party appraisals that take into consideration market-based information such as recent sales activity for similar assets in the property’s market. Other real estate owned, including both foreclosed property and surplus banking property, are level 3 assets that are adjusted to fair value, less estimated selling costs, upon transfer to other real estate owned. Subsequently, other real estate owned is carried at the lower of carrying value or fair value less estimated selling costs. Fair values are determined by sales agreement or third-party appraisals as discounted for estimated selling costs, information from comparable sales, and marketability of the property. The fair value information presented below is not as of the period-end, rather it was as of the date the fair value adjustment was recorded during the twelve months for each of the dates presented below, and excludes nonrecurring fair value measurements of assets no longer on the balance sheet. The following tables present the Company’s financial assets that are measured at fair value on a nonrecurring basis for each of the fair value hierarchy levels.      March 31, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Collateral-dependent impaired loans $ — $ 205,945 $ — $ 205,945  Other real estate owned — — 5,493 5,493  Total nonrecurring fair value measurements $ — $ 205,945 $ 5,493 $ 211,438      December 31, 2017  (in thousands) Level 1 Level 2 Level 3 Total  Collateral-dependent impaired loans $ — $ 184,205 $ — $ 184,205  Other real estate owned — — 6,928 6,928  Total nonrecurring fair value measurements $ — $ 184,205 $ 6,928 $ 191,133  Accounting guidance from the FASB requires the disclosure of estimated fair value information about certain on- and off-balance sheet financial instruments, including those financial instruments that are not measured and reported at fair value on a recurring basis. The significant methods and assumptions used by the Company to estimate the fair value of financial i nstruments are discussed below. Cash, Short ‑Term Investments and Federal Funds Sold – For these short ‑term instruments, the carrying amount is a reasonable estimate of fair value. Securities – The fair value measurement for securities available for sale was discussed earlier in the note. The same measurement techniques were applied to the valuation of securities held to maturity. Loans, Net – The fair value measurement for certain impaired loans was discussed earlier in the note. For the remaining portfolio, fair values were generally determined by discounting scheduled cash flows using discount rates determined with reference to current market rates at which loans with similar terms would be made to borrowers of similar credit quality. Loans Held for Sale – These loans are recorded at fair value and carried at the lower of cost or market. The carrying amount is considered a reasonable estimate of fair value. Deposits – The accounting guidance requires that the fair value of deposits with no stated maturity, such as noninterest-bearing demand deposits, interest-bearing checking and savings accounts, be assigned fair values equal to amounts payable upon demand (“carrying amou nts”). The fair value of fixed maturity certificates of deposit is estimated using the rates currently offered for deposits of similar remaining maturities. Securities Sold under Agreements to Repurchase, Federal Funds Purchased, and FHLB Borrowings – For these short-term liabilities, the carrying amount is a reasonable estimate of fair value. Long-Term Debt – The fair value is estimated by discounting the future contractual cash flows using current market rates at which debt with similar terms could be obtained. Derivative Financial Instruments – The fair value measurement for derivative financial instruments was discussed earlier in the note. The following tables present the estimated fair values of the Company’s financial instruments by fair value hierarchy levels and the corresponding carrying amount at March 31, 2018 and December 31, 2017 .      March 31, 2018  Total Fair Carrying  (in thousands) Level 1 Level 2 Level 3 Value Amount  Financial assets:  Cash, interest-bearing bank deposits, and federal funds sold $ 315,401 $ — $ — $ 315,401 $ 315,401  Available for sale securities — 2,915,648 — 2,915,648 2,915,648  Held to maturity securities — 2,952,295 — 2,952,295 3,014,428  Loans, net — 205,945 18,337,770 18,543,715 18,881,791  Loans held for sale — 21,827 — 21,827 21,827  Derivative financial instruments — 12,682 — 12,682 12,682  Financial liabilities:  Deposits $ — $ — $ 22,438,772 $ 22,438,772 $ 22,485,722  Federal funds purchased 25,967 — — 25,967 25,967  Securities sold under agreements to repurchase 443,151 — — 443,151 443,151  FHLB short-term borrowings 982,979 — — 982,979 982,979  Long-term debt — 297,555 — 297,555 300,443  Derivative financial instruments — 22,529 — 22,529 22,529      December 31, 2017  Total Fair Carrying  (in thousands) Level 1 Level 2 Level 3 Value Amount  Financial assets:  Cash, interest-bearing bank deposits, and federal funds sold $ 479,332 $ — $ — $ 479,332 $ 479,332  Available for sale securities — 2,910,869 — 2,910,869 2,910,869  Held to maturity securities — 2,962,010 — 2,962,010 2,977,511  Loans, net — 184,205 18,403,303 18,587,508 18,786,855  Loans held for sale — 39,865 — 39,865 39,865  Derivative financial instruments — 14,157 — 14,157 14,157  Financial liabilities:  Deposits $ — $ — $ 22,238,847 $ 22,238,847 $ 22,253,202  Federal funds purchased 140,754 — — 140,754 140,754  Securities sold under agreements to repurchase 430,569 — — 430,569 430,569  FHLB short-term borrowings 1,132,567 — — 1,132,567 1,132,567  Long-term debt — 303,631 — 303,631 305,513  Derivative financial instruments — 14,389 — 14,389 14,389 

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2018
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncements	15. Recent Accounting Pronouncements  Accounting Standards Adopted in 2018  In August 2017, the FASB issued ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities,” with the objective of improving financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. The update provides changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The amendments in this update are effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted in any interim period after issuance of the update. All transition requirements and elections are to be applied to hedging relationships existing on the date of adoption, and the effect of the adoption should be reflected as of the beginning of the fiscal year of adoption. The Company early adopted this standard effective January 1, 2018 and has made certain adjustments to its existing designation documentation for active hedging relationships in order to take advantage of specific provisions in the new guidance and to fully align its documentation with the ASU. The adoption of this standard did not have a material impact on its financial condition or results of operations. See further discussion in Note 6 – Derivatives.  In March 2017, the FASB issued ASU 2017-07, “Compensation – Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Costs,” to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. The amendments require that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. The amendments also allow only the service cost component to be eligible for capitalization when applicable. These amendments are effective for public business entities for annual periods beginning after December 15, 2017, including interim periods within those annual periods. Disclosures of the nature of and reason for the change in accounting principle are required in the first interim and annual periods of adoption. The Company adopted the standard effective January 1, 2018 and the amendments were applied retrospectively for the presentation of the service cost component and the other components of net periodic pension and postretirement benefit costs in the statement of income. Refer to Note 12 – Retirement Plans – for detail on the components of net periodic pension and post-retirement benefit costs that were reclassified for each reporting period. The provisions of this update apply only to presentation and therefore did not have a material impact on the Company’s financial condition or results of operations.  In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” affecting any entity that enters into contracts with customers to transfer goods or services or enters into contracts for the transfer of nonfinancial assets unless those contracts are within the scope of other standards. The core principle of this standard is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Most revenue associated with financial instruments, including interest and loan origination fees, is outside the scope of the guidance. Gains and losses on investment securities, derivatives, and sales of financial instruments are also excluded from the scope. Subsequent to issuance of the revenue recognition guidance, the FASB has issued several updates that deferred by one year the effective date for revenue recognition guidance; clarified its guidance for performing the principal-versus-agent analysis; clarified guidance for identifying performance obligations allowing entities to ignore immaterial promised goods and services in the context of a contract with a customer and other clarifying guidance and technical corrections. Entities could elect to adopt the guidance either on a full or modified retrospective basis. The standard was effective and the Company adopted this guidance on January 1, 2018, using the modified retrospective approach. The Company inventoried and evaluated its contracts with customers for compliance with the standard. The Company did not identify material changes to the timing of revenue recognition and the adoption of this guidance did not have a material impact on its financial condition or results of operations. See Note 8 - Revenue Recognition for additional information regarding the implementation of this standard.  Additionally, the following ASUs were applicable to the Company January 1, 2018, but did not have a significant impact on the Company’s consolidated financial statements:  · ASU 2018-05, Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 (SEC Update); · ASU 2018-03,Technical Corrections and Improvements to Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities; · ASU 2017-09, Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting; · ASU 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business; · ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other than Inventory; · ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments; and · ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities  Issued but Not Yet Adopted Accounting Standards  In June 2016, the FASB issued ASU 2016-13, “Financial Instruments – Credits Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” to improve financial reporting by requiring timelier recording of credit losses on loans and other financial instruments held by financial institutions and other organizations. The ASU, more commonly referred to as Current Expected Credit Losses, or CECL, requires the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques currently applied will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. Organizations will continue to use judgment to determine which loss estimation method is appropriate for their circumstances. In addition, the ASU amends the accounting for credit losses on debt securities and purchased financial assets with credit deterioration. The ASU is effective for SEC filers for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, with a cumulative-effect adjustment to retained earnings as of the beginning of the year of adoption. Early application is permitted for all organizations for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company is not planning to early adopt this guidance. The Company has begun the implementation process by engaging a third party consultant and forming a cross-functional working group comprised of individuals from various areas including credit, finance, risk management and information technology. Three work streams have been created to complete balance sheet scoping, execute system implementation, and develop the expected credit loss models. While the Company has not yet quantified the financial impact of adoption, the expectation is that application of this guidance will result in an increase in the allowance for loan losses given the change in methodology from covering losses inherent in the portfolio to covering losses over the remaining expected life of the portfolio, and the reclassification of nonaccretable difference on purchased credit impaired loans to allowance (offset by an increase in the carrying value of the related loans). Application of the guidance is also expected to result in the establishment of an allowance for credit loss on held to maturity debt securities. The amount of the increase in these allowances will be impacted by the portfolio composition and quality at the adoption date as well as economic conditions and forecasts at that time.  In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” that provides new lease accounting guidance. With the exception of short-term leases, lessees will be required to recognize a lease liability representing the lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis, and a right-of-use asset representing the lessee’s right to use, or control the use of, a specified asset for the lease term. Consequently, lessees will no longer be able to utilize leases a source of off-balance sheet financing. Lessor accounting is largely unchanged under the new guidance, except for clarification of the definition of initial direct costs which may impact the timing of recognition of those costs. Public business entities are required to apply the amendments for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. In the first quarter of 2018, the FASB issued a targeted improvement standard that allows an additional transition method to the new lease standard by recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, an entity’s reporting for the comparative periods presented in the financial statements in which the entity adopts the new lease requirements would continue to be in accordance with current GAAP (Topic 840), including disclosures. The Company plans to elect this transition method. The Company has begun its review of existing lease and service contracts that may include embedded leases. The Company also begun the process of upgrading its existing third-party leasing software that will be used for implementation, with a targeted completion date in the fourth quarter of 2018. The Company expects a gross-up of its Consolidated Balance Sheets as a result of recognizing lease liabilities and right of use assets; the extent of such is under evaluation. The Company does not expect material changes to its consolidated results of operations as a result of the application of this guidance. 

Basis of Presentation24

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Basis of Presentation [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Hancock Holding Company and all other entities in which it has a controlling interest (the “Company”). The financial statements include all adjustments that are, in the opinion of management, necessary to fairly state the Company’s financial condition, results of operations, changes in stockholders’ equity and cash flows for the interim periods presented. The Company has also evaluated all subsequent events for potential recognition and disclosure through the date of the filing of this Quarterly Report on Form 10-Q. Some financial information and disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) have been condensed or omitted in this Quarterly Report on Form 10-Q pursuant to Securities and Exchange Commission rules and regulations. These financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Financial information reported in these financial statements is not necessarily indicative of the Company’s financial condition, results of operations, or cash flows for any other interim or annual period. Certain prior period amounts have been reclassified to conform to the current period presentation. These changes in presentation did not have a material impact on the Company’s financial condition or operating results.
Use of Estimates	Use of Estimates The accounting principles the Company follows and the methods for applying these principles conform to GAAP and general practices followed by the banking industry. These accounting principles require management to make estimates and assumptions about future events that affect the amounts reported in the consolidated financial statements and the accompanying notes. Actual results could differ from those estimates.
Critical Accounting Policies and Estimates	Critical Accounting Policies and Estimates  There were no material changes or developments during the reporting period with respect to methodologies that the Company uses when applying what management believes are critical accounting policies and developing critical accounting estimates as disclosed in its Annual Report on Form 10-K for the year ended December 31, 2017. Refer to Note 15 – Recent Accounting Pronouncements for a discussion of accounting standards adopted during the quarter ended March 31, 2018.

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Gain (Loss) on Investments [Line Items]
Amortized Cost and Fair Value of Securities Available for Sale	   Securities Available for Sale  (in thousands) March 31, 2018 December 31, 2017  Gross Gross Gross Gross  Amortized Unrealized Unrealized Fair Amortized Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  U.S. Treasury and government agency securities $ 97,431 — 3,547 93,884 $ 99,535 $ — $ 2,263 $ 97,272  Municipal obligations 245,164 211 8,084 237,291 245,997 1,135 3,346 243,786  Residential mortgage-backed securities 1,787,382 3,552 47,391 1,743,543 1,729,989 5,611 20,387 1,715,213  Commercial mortgage-backed securities 715,360 — 35,088 680,272 704,518 480 17,863 687,135  Collateralized mortgage obligations 158,114 — 2,956 155,158 165,518 4 1,559 163,963  Corporate debt securities 5,500 — — 5,500 3,500 — — 3,500  $ 3,008,951 $ 3,763 $ 97,066 $ 2,915,648 $ 2,949,057 $ 7,230 $ 45,418 $ 2,910,869 
Amortized Cost and Fair Value of Securities Held to Maturity	   Securities Held to Maturity  (in thousands) March 31, 2018 December 31, 2017  Gross Gross Gross Gross  Amortized Unrealized Unrealized Fair Amortized Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  U.S. Treasury and government agency securities $ 50,000 — 576 49,424 $ 50,000 $ — $ 289 $ 49,711  Municipal obligations 707,581 1,315 13,453 695,443 723,094 8,323 4,245 727,172  Residential mortgage-backed securities 695,655 721 10,624 685,752 725,748 4,175 2,690 727,233  Commercial mortgage-backed securities 316,966 — 11,400 305,566 317,185 40 3,915 313,310  Collateralized mortgage obligations 1,244,226 391 28,507 1,216,110 1,161,484 572 17,472 1,144,584  $ 3,014,428 $ 2,427 $ 64,560 $ 2,952,295 $ 2,977,511 $ 13,110 $ 28,611 $ 2,962,010 
Available for Sale [Member]
Gain (Loss) on Investments [Line Items]
Amortized Cost and Fair Value of Debt Securities by Contractual Maturity	  Debt Securities Available for Sale Amortized Fair (in thousands) Cost Value Due in one year or less $ 7,388 $ 7,408 Due after one year through five years 45,623 45,740 Due after five years through ten years 1,249,127 1,202,997 Due after ten years 1,706,813 1,659,503 Total available for sale debt securities $ 3,008,951 $ 2,915,648  
Securities with Unrealized Losses	   Available for Sale  March 31, 2018 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ 43,521 1,214 50,362 2,333 $ 93,883 $ 3,547  Municipal obligations 54,330 948 169,119 7,136 223,449 8,084  Residential mortgage-backed securities 654,990 14,667 850,853 32,724 1,505,843 47,391  Commercial mortgage-backed securities 279,631 8,091 400,641 26,997 680,272 35,088  Collateralized mortgage obligations 122,186 2,324 32,972 632 155,158 2,956  $ 1,154,658 $ 27,244 $ 1,503,947 $ 69,822 $ 2,658,605 $ 97,066       Available for Sale  December 31, 2017 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ 45,616 $ 42 $ 51,157 $ 2,221 $ 96,773 $ 2,263  Municipal obligations 2,768 11 173,530 3,335 176,298 3,346  Residential mortgage-backed securities 461,835 4,195 898,099 16,192 1,359,934 20,387  Commercial mortgage-backed securities 203,618 995 411,046 16,868 614,664 17,863  Collateralized mortgage obligations 128,174 1,076 35,488 483 163,662 1,559  $ 842,011 $ 6,319 $ 1,569,320 $ 39,099 $ 2,411,331 $ 45,418 
Held to Maturity [Member]
Gain (Loss) on Investments [Line Items]
Amortized Cost and Fair Value of Debt Securities by Contractual Maturity	 Debt Securities Held to Maturity Amortized Fair (in thousands) Cost Value Due in one year or less $ 4,190 $ 4,205 Due after one year through five years 132,047 131,197 Due after five years through ten years 1,478,419 1,446,343 Due after ten years 1,399,772 1,370,550 Total held to maturity securities $ 3,014,428 $ 2,952,295 
Securities with Unrealized Losses	   Held to maturity  March 31, 2018 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ — — 49,424 576 $ 49,424 $ 576  Municipal obligations 341,011 4,530 221,438 8,923 562,449 13,453  Residential mortgage-backed securities 403,985 4,090 224,200 6,534 628,185 10,624  Commercial mortgage-backed securities 234,468 6,845 71,098 4,555 305,566 11,400  Collateralized mortgage obligations 672,660 12,567 441,866 15,940 1,114,526 28,507  $ 1,652,124 $ 28,032 $ 1,008,026 $ 36,528 $ 2,660,150 $ 64,560      Held to maturity  December 31, 2017 Losses < 12 months Losses 12 months or > Total  Gross Gross Gross  Fair Unrealized Fair Unrealized Fair Unrealized  (in thousands) Value Losses Value Losses Value Losses  U.S. Treasury and government agency securities $ — $ — $ 49,711 $ 289 $ 49,711 $ 289  Municipal obligations 14,603 19 230,960 4,226 245,563 4,245  Residential mortgage-backed securities 8,815 99 230,277 2,591 239,092 2,690  Commercial mortgage-backed securities 174,882 744 72,499 3,171 247,381 3,915  Collateralized mortgage obligations 570,289 5,653 472,536 11,819 1,042,825 17,472  $ 768,589 $ 6,515 $ 1,055,983 $ 22,096 $ 1,824,572 28,611 

Loans and Allowance for Loan 26

Loans and Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, Net of Unearned Income	   March 31, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 8,336,222 $ 8,297,937  Commercial real estate - owner occupied 2,185,543 2,142,439  Total commercial & industrial 10,521,765 10,440,376  Commercial real estate - income producing 2,394,862 2,384,599  Construction and land development 1,413,878 1,373,421  Residential mortgages 2,732,821 2,690,472  Consumer 2,029,178 2,115,295  Total loans $ 19,092,504 $ 19,004,163 
Allowance for Loan Losses by Portfolio Class	   Commercial Commercial  Commercial real estate- Total real estate- Construction  non-real owner commercial & income and land Residential  (in thousands) estate occupied industrial producing development mortgages Consumer Total  Three Months Ended March 31, 2018  Allowance for loan losses:  Beginning balance $ 127,918 $ 12,962 $ 140,880 $ 13,709 $ 7,372 $ 24,844 $ 30,503 $ 217,308  Charge-offs (9,335) (851) (10,186) — (10) (192) (8,048) (18,436)  Recoveries 4,146 88 4,234 63 29 116 1,794 6,236  Net provision for loan losses 3,877 1,421 5,298 (787) 2,533 150 5,059 12,253  Reduction as a result of sale of subsidiary — — — — — — (6,648) (6,648)  Ending balance $ 126,606 $ 13,620 $ 140,226 $ 12,985 $ 9,924 $ 24,918 $ 22,660 $ 210,713   Allowance at end of period :  Individually evaluated for impairment $ 20,356 $ 2,475 $ 22,831 $ 1,261 $ 1 $ 276 $ 232 $ 24,601  Amounts related to purchased credit impaired loans 471 495 966 576 173 11,720 612 14,047  Collectively evaluated for impairment 105,779 10,650 116,429 11,148 9,750 12,922 21,816 172,065  Total allowance $ 126,606 $ 13,620 $ 140,226 $ 12,985 $ 9,924 $ 24,918 $ 22,660 $ 210,713  Loans at end of period :  Individually evaluated for impairment $ 323,913 $ 30,318 $ 354,231 $ 14,071 $ 113 $ 8,338 $ 617 $ 377,370  Purchased credit impaired loans 8,510 8,384 16,894 4,361 5,843 116,409 5,876 149,383  Collectively evaluated for impairment 8,003,799 2,146,841 10,150,640 2,376,430 1,407,922 2,608,074 2,022,685 18,565,751  Total loans $ 8,336,222 $ 2,185,543 $ 10,521,765 $ 2,394,862 $ 1,413,878 $ 2,732,821 $ 2,029,178 $ 19,092,504        Commercial Commercial  Commercial real estate- Total real estate- Construction  non-real owner commercial & income and land Residential  (in thousands) estate occupied industrial producing development mortgages Consumer Total  Three Months Ended March 31, 2017  Allowance for loan losses:  Beginning balance $ 147,052 $ 11,083 $ 158,135 $ 13,509 $ 6,271 $ 25,361 $ 26,142 $ 229,418  Charge-offs (24,791) (29) (24,820) (7) (91) (348) (8,678) (33,944)  Recoveries 938 275 1,213 375 471 113 1,743 3,915  Net provision for loan losses 8,101 193 8,294 (266) 69 376 7,518 15,991  Decrease in FDIC loss share receivable (31) — (31) — — (1,696) (103) (1,830)  Ending balance $ 131,269 $ 11,522 $ 142,791 $ 13,611 $ 6,720 $ 23,806 $ 26,622 $ 213,550   Allowance at end of period :  Individually evaluated for impairment $ 15,017 $ 76 $ 15,093 $ 1,114 $ 1 $ 94 $ 199 $ 16,501  Amounts related to purchased credit impaired loans 411 787 1,198 213 283 13,286 1,019 15,999  Collectively evaluated for impairment 115,841 10,659 126,500 12,284 6,436 10,426 25,404 181,050  Total allowance $ 131,269 $ 11,522 $ 142,791 $ 13,611 $ 6,720 $ 23,806 $ 26,622 $ 213,550  Loans at end of period :  Individually evaluated for impairment $ 231,988 $ 3,894 $ 235,882 $ 13,599 $ 1,592 $ 3,236 $ 2,149 $ 256,458  Purchased credit impaired loans 6,693 12,468 19,161 7,669 4,326 138,260 9,951 179,367  Collectively evaluated for impairment 7,835,606 2,031,089 9,866,695 2,483,836 1,246,749 2,124,767 2,046,996 17,769,043  Total loans $ 8,074,287 $ 2,047,451 $ 10,121,738 $ 2,505,104 $ 1,252,667 $ 2,266,263 $ 2,059,096 $ 18,204,868  
Composition of Nonaccrual Loans by Portfolio Class	   March 31, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 179,203 $ 152,863  Commercial real estate - owner occupied 27,387 25,989  Total commercial & industrial 206,590 178,852  Commercial real estate - income producing 15,633 14,574  Construction and land development 3,724 3,807  Residential mortgages 35,069 40,480  Consumer 14,163 15,087  Total loans $ 275,179 $ 252,800 
Troubled Debt Restructurings Modified by Portfolio Class	   Three Months Ended  ($ in thousands) March 31, 2018 March 31, 2017  Pre-Modification Post-Modification Pre-Modification Post-Modification  Outstanding Outstanding Outstanding Outstanding  Number of Recorded Recorded Number of Recorded Recorded  Troubled Debt Restructurings: Contracts Investment Investment Contracts Investment Investment  Commercial non-real estate 13 $ 55,482 $ 55,482 9 $ 38,659 $ 38,659  Commercial real estate - owner occupied 1 5,909 5,909 1 656 656  Total commercial & industrial 14 61,391 61,391 10 39,315 39,315  Commercial real estate - income producing 1 1,564 1,564 2 5,527 5,527  Construction and land development 1 43 43 — — —  Residential mortgages — — — 1 250 250  Consumer 1 222 222 — — —  Total loans 17 $ 63,220 $ 63,220 13 $ 45,092 $ 45,092 
Loans Individually Evaluated for Impairment Disaggregated by Portfolio Class	   March 31, 2018  Recorded investment Recorded investment Unpaid  (in thousands) without an allowance with an allowance principal balance Related allowance  Commercial non-real estate $ 108,898 $ 215,015 $ 335,178 $ 20,356  Commercial real estate - owner occupied 6,064 24,254 30,997 2,475  Total commercial & industrial 114,962 239,269 366,175 22,831  Commercial real estate - income producing 6,055 8,016 14,269 1,261  Construction and land development 100 13 114 1  Residential mortgages 5,861 2,477 11,682 276  Consumer 14 603 718 232  Total loans $ 126,992 $ 250,378 $ 392,958 $ 24,601    December 31, 2017  Recorded investment Recorded investment Unpaid  (in thousands) without an allowance with an allowance principal balance Related allowance  Commercial non-real estate $ 116,682 $ 151,199 $ 285,685 $ 16,129  Commercial real estate - owner occupied 16,927 4,564 24,829 793  Total commercial & industrial 133,609 155,763 310,514 16,922  Commercial real estate - income producing 5,101 10,429 15,687 1,326  Construction and land development 100 263 363 11  Residential mortgages 8,245 2,395 13,855 189  Consumer — 1,292 1,294 118  Total loans $ 147,055 $ 170,142 $ 341,713 $ 18,566 The tables below present the average balances and interest income for total impaired loans for the three months ended March 31, 2018 and 2017. Interest income recognized represents interest on accruing loans modified in a TDR.      Three Months Ended  March 31, 2018 March 31, 2017  Average Interest Average Interest  recorded income recorded income  (in thousands) investment recognized investment recognized  Commercial non-real estate $ 295,897 $ 1,586 $ 251,625 $ 337  Commercial real estate - owner occupied 25,905 66 5,081 4  Total commercial & industrial 321,802 1,652 256,706 341  Commercial real estate - income producing 14,801 25 14,487 43  Construction and land development 238 — 1,766 —  Residential mortgages 9,489 5 3,792 2  Consumer 955 9 2,152 2  Total loans $ 347,285 $ 1,691 $ 278,903 $ 388 
Age Analysis of Past Due Loans by Portfolio Class	   Recorded  Greater than investment  30-59 days 60-89 days 90 days Total Total > 90 days and  March 31, 2018 past due past due past due past due Current Loans still accruing  (in thousands)  Commercial non-real estate $ 45,309 $ 18,497 $ 130,360 $ 194,166 $ 8,142,056 $ 8,336,222 $ 20,330  Commercial real estate - owner occupied 7,464 115 22,138 29,717 2,155,826 2,185,543 1,360  Total commercial & industrial 52,773 18,612 152,498 223,883 10,297,882 10,521,765 21,690  Commercial real estate - income producing 928 1,954 8,419 11,301 2,383,561 2,394,862 2,771  Construction and land development 6,537 416 3,115 10,068 1,403,810 1,413,878 259  Residential mortgages 32,815 4,496 20,122 57,433 2,675,388 2,732,821 1,170  Consumer 16,083 5,124 7,542 28,749 2,000,429 2,029,178 573  Total $ 109,136 $ 30,602 $ 191,696 $ 331,434 $ 18,761,070 $ 19,092,504 $ 26,463      Recorded  Greater than investment  30-59 days 60-89 days 90 days Total Total > 90 days and  December 31, 2017 past due past due past due past due Current Loans still accruing  (in thousands)  Commercial non-real estate $ 62,766 $ 10,761 $ 92,982 $ 166,509 $ 8,131,428 $ 8,297,937 $ 21,989  Commercial real estate - owner occupied 8,493 648 15,517 24,658 2,117,781 2,142,439 2,032  Total commercial & industrial 71,259 11,409 108,499 191,167 10,249,209 10,440,376 24,021  Commercial real estate - income producing 5,315 2,165 6,081 13,561 2,371,038 2,384,599 489  Construction and land development 4,113 1,056 3,412 8,581 1,364,840 1,373,421 477  Residential mortgages 33,621 10,554 30,537 74,712 2,615,760 2,690,472 2,208  Consumer 22,959 7,816 8,553 39,328 2,075,967 2,115,295 571  Total $ 137,267 $ 33,000 $ 157,082 $ 327,349 $ 18,676,814 $ 19,004,163 $ 27,766 
Changes in Carrying Amount of Purchased Credit Impaired Loans and Related Accretable Yield	   March 31, 2018 December 31, 2017  Carrying Carrying  Amount Accretable Amount Accretable  (in thousands) of Loans Yield of Loans Yield  Balance at beginning of period $ 153,403 $ 62,517 $ 190,915 $ 113,686  Addition of cost recovery loans - FNBC I — — 15,000 —  Payments received, net (8,288) (1,703) (69,591) (7,412)  Accretion 4,268 (4,268) 17,079 (17,079)  Increase in expected cash flows based on actual cash flows and changes in cash flow assumptions — (956) — (30,379)  Net transfers from nonaccretable difference to accretable yield — — — 3,701  Balance at end of period $ 149,383 $ 55,590 $ 153,403 $ 62,517 
Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Quality Indicators by Segments and Portfolio Class	   March 31, 2018  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial & industrial Commercial real estate - income producing Construction and land development Total commercial  Grade:  Pass $ 7,250,715 $ 1,954,384 $ 9,205,099 $ 2,268,358 $ 1,334,456 $ 12,807,913  Pass-Watch 269,657 51,856 321,513 58,092 59,208 438,813  Special Mention 100,005 35,971 135,976 9,344 6,279 151,599  Substandard 715,827 143,332 859,159 59,068 13,935 932,162  Doubtful 18 — 18 — — 18  Total $ 8,336,222 $ 2,185,543 $ 10,521,765 $ 2,394,862 $ 1,413,878 $ 14,330,505   December 31, 2017  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial & industrial Commercial real estate - income producing Construction and land development Total commercial  Grade:  Pass $ 7,190,604 $ 1,896,366 $ 9,086,970 $ 2,223,245 $ 1,291,638 $ 12,601,853  Pass-Watch 293,069 82,913 375,982 83,444 60,804 520,230  Special Mention 80,649 27,456 108,105 13,244 4,788 126,137  Substandard 733,558 135,704 869,262 64,658 16,191 950,111  Doubtful 57 — 57 8 — 65  Total $ 8,297,937 $ 2,142,439 $ 10,440,376 $ 2,384,599 $ 1,373,421 $ 14,198,396 
Residential Mortgage and Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Quality Indicators by Segments and Portfolio Class	   March 31, 2018 December 31, 2017  (in thousands) Residential mortgage Consumer Total Residential mortgage Consumer Total  Performing $ 2,696,582 $ 2,014,442 $ 4,711,024 $ 2,647,784 $ 2,099,637 $ 4,747,421  Nonperforming 36,239 14,736 50,975 42,688 15,658 58,346  Total $ 2,732,821 $ 2,029,178 $ 4,761,999 $ 2,690,472 $ 2,115,295 $ 4,805,767 

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2018
Derivatives [Abstract]
Fair Values of Derivative Financial Instruments	     March 31, 2018 December 31, 2017  Derivative (1) Derivative (1)  (in thousands) Type of Hedge Notional or Contractual Amount Assets Liabilities Notional or Contractual Amount Assets Liabilities  Derivatives designated as hedging instruments:  Interest rate swaps Cash Flow $ 875,000 $ 1,752 $ 12,667 $ 875,000 $ — $ 14,020  Interest rate swaps Fair Value 483,110 — 3,948 483,110 — 2,475  $ 1,358,110 $ 1,752 $ 16,615 $ 1,358,110 $ — $ 16,495  Derivatives not designated as hedging instruments:  Interest rate swaps (2) N/A $ 1,184,109 $ 20,680 $ 20,710 $ 1,144,789 $ 15,408 $ 15,857  Risk participation agreements N/A 121,479 13 61 119,951 23 109  Forward commitments to sell residential mortgage loans N/A 81,326 847 454 80,462 1,000 290  Interest rate-lock commitments on residential mortgage loans N/A 61,904 376 789 53,724 186 782  Foreign exchange forward contracts N/A 42,815 3,096 3,062 42,260 2,453 2,419  1,491,633 25,012 25,076 1,441,186 19,070 19,457  Total derivatives $ 2,849,743 $ 26,764 $ 41,691 $ 2,799,296 $ 19,070 $ 35,952  Less: netting adjustment (3) (14,081) (19,162) (4,913) (21,563)  Total derivative assets/liabilities $ 12,683 $ 22,529 $ 14,157 $ 14,389 (1) Derivative assets and liabilities are reported at fair value in other assets or other liabilities, respectively, in the consolidated balance sheets. (2) The notional amount represents both the customer accommodation agreements and offsetting agreements with unrelated financial institutions.  (3) Represents balance sheet netting of derivative assets and liabilities for variation margin collateral held or placed with the same central clearing counterparty. See offsetting assets and liabilities for further information. 
Offsetting Derivative Assets and Liabilities Subject to Master Netting Arrangements	   (in thousands) Gross Amounts Net Amounts Gross Amounts Not Offset in the Statement of Income  Description Gross Amounts Recognized Offset in the Statement of Income Presented in the Statement of Income Financial Instruments Cash Collateral Net Amount  As of March 31, 2018  Derivative Assets $ 18,822 $ (14,314) $ 4,508 $ 1,517 $ — $ 2,991   Derivative Liabilities $ 18,081 $ (16,497) $ 1,584 $ 1,517 $ 4,770 $ (4,703)      (in thousands) Gross Amounts Net Amounts Gross Amounts Not Offset in the Statement of Income  Description Gross Amounts Recognized Offset in the Statement of Income Presented in the Statement of Income Financial Instruments Cash Collateral Net Amount  As of December 31, 2017  Derivative Assets $ 7,155 $ (5,007) $ 2,148 $ 2,148 $ — $ —   Derivative Liabilities $ 24,015 $ (20,077) $ 3,938 $ 2,148 $ 4,099 $ (2,309) 

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2018
Stockholders' Equity [Abstract]
Components of Accumulated Other Comprehensive Income (Loss)	   Available HTM Securities  for Sale Transferred Employee Cash  (in thousands) Securities from AFS Benefit Plans Flow Hedges Total  Balance, December 31, 2016 $ (28,679) $ (14,392) $ (72,501) $ (4,960) $ (120,532)  Other comprehensive income (loss) before income taxes:  Net change in unrealized gain 2,319 — — (1,135) 1,184  Reclassification of net (gain) loss realized and included in earnings — — 1,387 — 1,387  Amortization of unrealized net loss on securities transferred to HTM — 650 — — 650  Income tax expense (benefit) 843 266 504 (412) 1,201  Balance, March 31, 2017 $ (27,203) $ (14,008) $ (71,618) $ (5,683) $ (118,512)  Balance, December 31, 2017 $ (29,512) $ (14,585) $ (79,078) $ (11,227) $ (134,402)  Other comprehensive income (loss) before income taxes:  Net change in unrealized gain (loss) (55,114) — — (7,130) (62,244)  Reclassification of net losses realized and included in earnings — — 1,177 619 1,796  Other valuation adjustments for employee benefit plan — — — —  Amortization of unrealized net loss on securities transferred to HTM — 755 — — 755  Income tax expense (benefit) (12,508) 171 267 (1,476) (13,546)  Balance, March 31, 2018 $ (72,118) $ (14,001) $ (78,168) $ (16,262) $ (180,549) 
Line Items in Consolidated Income Statements Affected by Amounts Reclassified from Accumulated Other Comprehensive Income	   Three Months Ended  Amount reclassified from AOCI (a) March 31, Affected line item on  (in thousands) 2018 2017 the statement of income  Amortization of unrealized net loss on securities transferred to HTM (755) (650) Interest income  Tax effect 171 266 Income taxes  Net of tax (584) (384) Net income  Amortization of defined benefit pension and post-retirement items (1,177) (1,387) Other noninterest expense (b)  Tax effect 267 504 Income taxes  Net of tax (910) (883) Net income  Reclassification of unrealized gain on cash flow hedges 336 — Interest income  Tax effect (76) — Income taxes  Net of tax 260 Net income  Amortization of loss on terminated cash flow hedges (954) — Interest income  Tax effect 216 — Income taxes  Net of tax (738) — Net income  Total reclassifications, net of tax $ (1,972) $ (1,267) Net income (a) Amounts in parenthesis indicate reduction in net income.  (b) These AOCI components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 1 2 – Retirement Plans for additional details).

Other Noninterest Income (Table

Other Noninterest Income (Tables)	3 Months Ended
	Mar. 31, 2018
Other Noninterest Income [Abstract]
Components of Other Noninterest Income	   Three Months Ended  March 31,  (in thousands) 2018 2017  Income from bank-owned life insurance $ 3,070 $ 2,652  Credit related fees 2,722 2,878  Income from derivatives 1,523 465  Gain (loss) on sales of assets (1,207) 4,125  Amortization of FDIC loss share receivable — (1,100)  Other miscellaneous 3,377 2,755  Total other noninterest income $ 9,485 $ 11,775 

Other Noninterest Expense (Tabl

Other Noninterest Expense (Tables)	3 Months Ended
	Mar. 31, 2018
Other Noninterest Expense [Abstract]
Components of Other Noninterest Expense	   Three Months Ended  March 31,  (in thousands) 2018 2017  Advertising $ 2,526 $ 3,077  Corporate value and franchise taxes 3,440 3,036  Printing and supplies 1,286 1,178  Travel expense 1,066 1,059  Entertainment and contributions 2,518 1,783  Tax credit investment amortization 874 1,212  Other retirement expense (4,463) (3,060)  Other miscellaneous 5,684 7,285  Total other noninterest expense $ 12,931 $ 15,570 

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Computation of Earnings Per Common Share	   Three Months Ended  March 31,  (in thousands, except per share data) 2018 2017  Numerator:  Net income to common shareholders $ 72,475 $ 49,014  Net income allocated to participating securities - basic and diluted 1,366 1,156  Net income allocated to common shareholders - basic and diluted $ 71,109 $ 47,858  Denominator:  Weighted-average common shares - basic $ 85,241 $ 84,365  Dilutive potential common shares 182 259  Weighted-average common shares - diluted $ 85,423 $ 84,624  Earnings per common share:  Basic $ 0.83 $ 0.57  Diluted $ 0.83 $ 0.57 

Retirement Plans (Tables)

Retirement Plans (Tables)	3 Months Ended
	Mar. 31, 2018
Retirement Plans [Abstract]
Components of Net Periodic Benefits Cost	   Other Post-  (in thousands) Pension Benefits Retirement Benefits  Three months Ended March 31, 2018 2017 2018 2017  Service cost $ 2,925 $ 3,750 $ 35 $ 48  Interest cost 3,923 4,123 137 180  Expected return on plan assets (9,700) (8,750) — —  Amortization of net loss and prior service costs 1,326 1,435 (149) (48)  Net periodic benefit cost (reduction of cost) $ (1,526) $ 558 $ 23 $ 180 

Share-Based Payment Arrangeme33

Share-Based Payment Arrangements (Tables)	3 Months Ended
	Mar. 31, 2018
Share-Based Payment Arrangements [Abstract]
Summary of Option Activity	   Weighted  Average  Weighted Remaining  Average Contractual Aggregate  Number of Exercise Term Intrinsic  Options Shares Price (Years) Value ($000)  Outstanding at January 1, 2018 88,301 $ 34.84 2.8 $ 1,294  Exercised/Released (24,793) 35.12 495  Cancelled/Forfeited — — —  Expired — — —  Outstanding at March 31, 2018 63,508 $ 34.73 2.6 $ 1,078  Exercisable at March 31, 2018 63,508 $ 34.73 2.6 $ 1,078 
Summary of Nonvested Restricted and Performance Shares	   Weighted  Average  Number of Grant Date  Shares Fair Value  Nonvested at January 1, 2018 1,708,942 $ 37.05  Granted 54,710 48.22  Vested (9,587) 35.90  Forfeited (30,376) 35.25  Nonvested at March 31, 2018 1,723,689 $ 37.44 

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Measurements [Abstract]
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	   March 31, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Assets  Available for sale debt securities:  U.S. Treasury and government agency securities $ — $ 93,884 $ — $ 93,884  Municipal obligations — 237,291 — 237,291  Corporate debt securities — 5,500 — 5,500  Residential mortgage-backed securities — 1,743,543 — 1,743,543  Commercial mortgage-backed securities — 680,272 — 680,272  Collateralized mortgage obligations — 155,158 — 155,158  Total available for sale securities — 2,915,648 — 2,915,648  Derivative assets (1) — 12,682 — 12,682  Total recurring fair value measurements - assets $ — $ 2,928,330 $ — $ 2,928,330  Liabilities  Derivative liabilities (1) $ — $ 22,529 $ — $ 22,529  Total recurring fair value measurements - liabilities $ — $ 22,529 $ — $ 22,529      December 31, 2017  (in thousands) Level 1 Level 2 Level 3 Total  Assets  Available for sale debt securities:  U.S. Treasury and government agency securities $ — $ 97,272 $ — $ 97,272  Municipal obligations — 243,786 — 243,786  Corporate debt securities — 3,500 — 3,500  Residential mortgage-backed securities — 1,715,213 — 1,715,213  Commercial mortgage-backed securities — 687,135 — 687,135  Collateralized mortgage obligations — 163,963 — 163,963  Total available for sale securities — 2,910,869 — 2,910,869  Derivative assets (1) — 14,157 — 14,157  Total recurring fair value measurements - assets $ — $ 2,925,026 $ — $ 2,925,026  Liabilities  Derivative liabilities (1) $ — $ 14,389 $ — $ 14,389  Total recurring fair value measurements - liabilities $ — $ 14,389 $ — $ 14,389  (1) For further disaggregation of derivative assets and liabilities, see Note 6 - Derivatives.
Financial Assets Measured at Fair Value on Nonrecurring Basis	   March 31, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Collateral-dependent impaired loans $ — $ 205,945 $ — $ 205,945  Other real estate owned — — 5,493 5,493  Total nonrecurring fair value measurements $ — $ 205,945 $ 5,493 $ 211,438      December 31, 2017  (in thousands) Level 1 Level 2 Level 3 Total  Collateral-dependent impaired loans $ — $ 184,205 $ — $ 184,205  Other real estate owned — — 6,928 6,928  Total nonrecurring fair value measurements $ — $ 184,205 $ 6,928 $ 191,133 
Estimated Fair Values of Financial Instruments	   March 31, 2018  Total Fair Carrying  (in thousands) Level 1 Level 2 Level 3 Value Amount  Financial assets:  Cash, interest-bearing bank deposits, and federal funds sold $ 315,401 $ — $ — $ 315,401 $ 315,401  Available for sale securities — 2,915,648 — 2,915,648 2,915,648  Held to maturity securities — 2,952,295 — 2,952,295 3,014,428  Loans, net — 205,945 18,337,770 18,543,715 18,881,791  Loans held for sale — 21,827 — 21,827 21,827  Derivative financial instruments — 12,682 — 12,682 12,682  Financial liabilities:  Deposits $ — $ — $ 22,438,772 $ 22,438,772 $ 22,485,722  Federal funds purchased 25,967 — — 25,967 25,967  Securities sold under agreements to repurchase 443,151 — — 443,151 443,151  FHLB short-term borrowings 982,979 — — 982,979 982,979  Long-term debt — 297,555 — 297,555 300,443  Derivative financial instruments — 22,529 — 22,529 22,529      December 31, 2017  Total Fair Carrying  (in thousands) Level 1 Level 2 Level 3 Value Amount  Financial assets:  Cash, interest-bearing bank deposits, and federal funds sold $ 479,332 $ — $ — $ 479,332 $ 479,332  Available for sale securities — 2,910,869 — 2,910,869 2,910,869  Held to maturity securities — 2,962,010 — 2,962,010 2,977,511  Loans, net — 184,205 18,403,303 18,587,508 18,786,855  Loans held for sale — 39,865 — 39,865 39,865  Derivative financial instruments — 14,157 — 14,157 14,157  Financial liabilities:  Deposits $ — $ — $ 22,238,847 $ 22,238,847 $ 22,253,202  Federal funds purchased 140,754 — — 140,754 140,754  Securities sold under agreements to repurchase 430,569 — — 430,569 430,569  FHLB short-term borrowings 1,132,567 — — 1,132,567 1,132,567  Long-term debt — 303,631 — 303,631 305,513  Derivative financial instruments — 14,389 — 14,389 14,389 

Acquisitions and Divestiture (N

Acquisitions and Divestiture (Narrative) (Details) $ in Millions	Mar. 09, 2018USD ($)	Apr. 28, 2017USD ($)	Mar. 10, 2017USD ($)entity
Harrison Finance Company [Member]
Business Acquisition [Line Items]
Loss from sale of consumer finance subsidiary	$ 1.1
Proceeds from sale of finance subsidiary	$ 78.3
FNBC I [Member] | Whitney Bank [Member]
Business Acquisition [Line Items]
Number of branches | entity			9
Net of cash acquired			$ 323
Cash consideration			326
Cash acquired			3
Acquisition, Premium amount to pay			$ 41.6
FNBC II [Member] | Whitney Bank [Member]
Business Acquisition [Line Items]
Cash received		$ 800
Cash acquired		158
Premium payment		35
Unpaid principal balance of the loans acquired, Net liabilities assumed		$ 642

Securities (Narrative) (Details

Securities (Narrative) (Details) $ in Billions	3 Months Ended
	Mar. 31, 2018USD ($)item	Mar. 31, 2017item	Dec. 31, 2017USD ($)
Securities [Abstract]
Securities classified as trading	$ 0		$ 0
Securities pledged as collateral	$ 3.4		$ 3.3
Sale of securities | item	0	0

Securities (Amortized Cost and

Securities (Amortized Cost and Fair Value of Securities Available for Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	$ 3,008,951	$ 2,949,057
Securities Available for Sale, Gross Unrealized Gains	3,763	7,230
Securities Available for Sale, Gross Unrealized Losses	97,066	45,418
Securities Available for Sale, Fair Value	2,915,648	2,910,869
U.S. Treasury And Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	97,431	99,535
Securities Available for Sale, Gross Unrealized Losses	3,547	2,263
Securities Available for Sale, Fair Value	93,884	97,272
Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	245,164	245,997
Securities Available for Sale, Gross Unrealized Gains	211	1,135
Securities Available for Sale, Gross Unrealized Losses	8,084	3,346
Securities Available for Sale, Fair Value	237,291	243,786
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	1,787,382	1,729,989
Securities Available for Sale, Gross Unrealized Gains	3,552	5,611
Securities Available for Sale, Gross Unrealized Losses	47,391	20,387
Securities Available for Sale, Fair Value	1,743,543	1,715,213
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	715,360	704,518
Securities Available for Sale, Gross Unrealized Gains		480
Securities Available for Sale, Gross Unrealized Losses	35,088	17,863
Securities Available for Sale, Fair Value	680,272	687,135
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	158,114	165,518
Securities Available for Sale, Gross Unrealized Gains		4
Securities Available for Sale, Gross Unrealized Losses	2,956	1,559
Securities Available for Sale, Fair Value	155,158	163,963
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	5,500	3,500
Securities Available for Sale, Fair Value	$ 5,500	$ 3,500

Securities (Amortized Cost an38

Securities (Amortized Cost and Fair Value of Securities Held to Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	$ 3,014,428	$ 2,977,511
Securities Held to Maturity, Gross Unrealized Gains	2,427	13,110
Securities Held to Maturity, Gross Unrealized Losses	64,560	28,611
Securities Held to Maturity, Fair Value	2,952,295	2,962,010
U.S. Treasury And Government Agency Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	50,000	50,000
Securities Held to Maturity, Gross Unrealized Losses	576	289
Securities Held to Maturity, Fair Value	49,424	49,711
Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	707,581	723,094
Securities Held to Maturity, Gross Unrealized Gains	1,315	8,323
Securities Held to Maturity, Gross Unrealized Losses	13,453	4,245
Securities Held to Maturity, Fair Value	695,443	727,172
Residential Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	695,655	725,748
Securities Held to Maturity, Gross Unrealized Gains	721	4,175
Securities Held to Maturity, Gross Unrealized Losses	10,624	2,690
Securities Held to Maturity, Fair Value	685,752	727,233
Commercial Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	316,966	317,185
Securities Held to Maturity, Gross Unrealized Gains		40
Securities Held to Maturity, Gross Unrealized Losses	11,400	3,915
Securities Held to Maturity, Fair Value	305,566	313,310
Collateralized Mortgage Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	1,244,226	1,161,484
Securities Held to Maturity, Gross Unrealized Gains	391	572
Securities Held to Maturity, Gross Unrealized Losses	28,507	17,472
Securities Held to Maturity, Fair Value	$ 1,216,110	$ 1,144,584

Securities (Amortized Cost an39

Securities (Amortized Cost and Fair Value of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Securities [Abstract]
Debt Securities Available for Sale, Due in one year or less, Amortized Cost	$ 7,388
Debt Securities Available for Sale, Due after one year through five years, Amortized Cost	45,623
Debt Securities Available for Sale, Due after five years through ten years, Amortized Cost	1,249,127
Debt Securities Available for Sale, Due after ten years, Amortized Cost	1,706,813
Total available for sale debt securities, Amortized Cost	3,008,951
Debt Securities Available for Sale, Due in one year or less, Fair Value	7,408
Debt Securities Available for Sale, Due after one year through five years, Fair Value	45,740
Debt Securities Available for Sale, Due after five years through ten years, Fair Value	1,202,997
Debt Securities Available for Sale, Due after ten years, Fair Value	1,659,503
Total available for sale debt securities, Fair Value	2,915,648
Debt Securities Held to Maturity, Due in one year or less, Amortized Cost	4,190
Debt Securities Held to Maturity, Due after one year through five years, Amortized Cost	132,047
Debt Securities Held to Maturity, Due after five years through ten years, Amortized Cost	1,478,419
Debt Securities Held to Maturity, Due after ten years, Amortized Cost	1,399,772
Total held to maturity debt securities, Amortized Cost	3,014,428	$ 2,977,511
Debt Securities Held to Maturity, Due in one year or less, Fair Value	4,205
Debt Securities Held to Maturity, Due after one year through five years, Fair Value	131,197
Debt Securities Held to Maturity, Due after five years through ten years, Fair Value	1,446,343
Debt Securities Held to Maturity, Due after ten years, Fair Value	1,370,550
Total held to maturity debt securities, Fair Value	$ 2,952,295	$ 2,962,010

Securities (Securities Availabl

Securities (Securities Available for Sale with Unrealized Losses) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	$ 1,154,658	$ 842,011
Available for sale, Losses less than 12 months, Gross Unrealized Losses	27,244	6,319
Available for sale, Losses 12 months or longer, Fair Value	1,503,947	1,569,320
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	69,822	39,099
Available for sale, Total, Fair Value	2,658,605	2,411,331
Available for sale, Total, Gross Unrealized Losses	97,066	45,418
U.S. Treasury And Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	43,521	45,616
Available for sale, Losses less than 12 months, Gross Unrealized Losses	1,214	42
Available for sale, Losses 12 months or longer, Fair Value	50,362	51,157
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	2,333	2,221
Available for sale, Total, Fair Value	93,883	96,773
Available for sale, Total, Gross Unrealized Losses	3,547	2,263
Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	54,330	2,768
Available for sale, Losses less than 12 months, Gross Unrealized Losses	948	11
Available for sale, Losses 12 months or longer, Fair Value	169,119	173,530
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	7,136	3,335
Available for sale, Total, Fair Value	223,449	176,298
Available for sale, Total, Gross Unrealized Losses	8,084	3,346
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	654,990	461,835
Available for sale, Losses less than 12 months, Gross Unrealized Losses	14,667	4,195
Available for sale, Losses 12 months or longer, Fair Value	850,853	898,099
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	32,724	16,192
Available for sale, Total, Fair Value	1,505,843	1,359,934
Available for sale, Total, Gross Unrealized Losses	47,391	20,387
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	279,631	203,618
Available for sale, Losses less than 12 months, Gross Unrealized Losses	8,091	995
Available for sale, Losses 12 months or longer, Fair Value	400,641	411,046
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	26,997	16,868
Available for sale, Total, Fair Value	680,272	614,664
Available for sale, Total, Gross Unrealized Losses	35,088	17,863
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	122,186	128,174
Available for sale, Losses less than 12 months, Gross Unrealized Losses	2,324	1,076
Available for sale, Losses 12 months or longer, Fair Value	32,972	35,488
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	632	483
Available for sale, Total, Fair Value	155,158	163,662
Available for sale, Total, Gross Unrealized Losses	$ 2,956	$ 1,559

Securities (Securities Held to

Securities (Securities Held to Maturity with Unrealized Losses) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	$ 1,652,124	$ 768,589
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	28,032	6,515
Held to maturity, Losses 12 months or longer, Fair Value	1,008,026	1,055,983
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	36,528	22,096
Held to maturity, Total, Fair Value	2,660,150	1,824,572
Held to maturity, Total, Gross Unrealized Losses	64,560	28,611
U.S. Treasury And Government Agency Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses 12 months or longer, Fair Value	49,424	49,711
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	576	289
Held to maturity, Total, Fair Value	49,424	49,711
Held to maturity, Total, Gross Unrealized Losses	576	289
Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	341,011	14,603
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	4,530	19
Held to maturity, Losses 12 months or longer, Fair Value	221,438	230,960
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	8,923	4,226
Held to maturity, Total, Fair Value	562,449	245,563
Held to maturity, Total, Gross Unrealized Losses	13,453	4,245
Residential Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	403,985	8,815
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	4,090	99
Held to maturity, Losses 12 months or longer, Fair Value	224,200	230,277
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	6,534	2,591
Held to maturity, Total, Fair Value	628,185	239,092
Held to maturity, Total, Gross Unrealized Losses	10,624	2,690
Commercial Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	234,468	174,882
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	6,845	744
Held to maturity, Losses 12 months or longer, Fair Value	71,098	72,499
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	4,555	3,171
Held to maturity, Total, Fair Value	305,566	247,381
Held to maturity, Total, Gross Unrealized Losses	11,400	3,915
Collateralized Mortgage Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	672,660	570,289
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	12,567	5,653
Held to maturity, Losses 12 months or longer, Fair Value	441,866	472,536
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	15,940	11,819
Held to maturity, Total, Fair Value	1,114,526	1,042,825
Held to maturity, Total, Gross Unrealized Losses	$ 28,507	$ 17,472

Loans and Allowance for Loan 42

Loans and Allowance for Loan Losses (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)loanagreement	Mar. 31, 2017USD ($)loan	Dec. 31, 2017USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 275,179		$ 252,800
TDRs both accruing and nonaccruing	284,500		219,700
Post-Modification outstanding recorded investment	$ 63,220	$ 45,092
Number of TDRs subsequently defaulted | loan	0	0
Unfunded commitment to borrowers related to modified TDR	$ 8,500		7,300
TDRs and loans impaired with minimum aggregate relationship balances	$ 1,000
Performing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period for which payments of principal and interest are past due	less than 90 days
Troubled Debt Restructurings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 118,000		99,200
Troubled Debt Restructurings [Member] | Loans With Extended Amortization Terms Or Other Payment Concessions [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Extended terms and other payment concessions	48,400	$ 27,400
Troubled Debt Restructurings [Member] | Loans With Significant Covenant Waivers [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Convenant waivers	14,600	10,700
Troubled Debt Restructurings [Member] | Loans With Other Modifications [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-Modification outstanding recorded investment	$ 200
Other modifications		$ 6,900
FDIC Loss Share Agreement [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loss share agreements | agreement	2
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 14,163		15,087
Post-Modification outstanding recorded investment	222
Real estate in process of foreclosure	7,800		7,500
Real estate acquired through foreclosure	$ 3,700		$ 3,400

Loans and Allowance for Loan 43

Loans and Allowance for Loan Losses (Loans, Net of Unearned Income) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 19,092,504	$ 19,004,163	$ 18,204,868
Residential Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,732,821	2,690,472	2,266,263
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,029,178	2,115,295	2,059,096
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,394,862	2,384,599	2,505,104
Construction and Land Development [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,413,878	1,373,421	1,252,667
Total Commercial And Industrial [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	10,521,765	10,440,376	10,121,738
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	8,336,222	8,297,937	8,074,287
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 2,185,543	$ 2,142,439	$ 2,047,451

Loans and Allowance for Loan 44

Loans and Allowance for Loan Losses (Allowance for Loan Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	$ 217,308	$ 229,418
Allowance for loan losses: Net provision for loan losses	12,253	15,991
Allowance for loan losses: Decrease in FDIC loss share receivable		(1,830)
Allowance for loan losses: Ending balance	210,713	213,550
Allowance for loan losses: Individually evaluated for impairment	24,601	16,501
Allowance for loan losses: Amounts related to purchased credit impaired loans	14,047	15,999
Allowance for loan losses: Collectively evaluated for impairment	172,065	181,050
Loans: Individually evaluated for impairment	377,370	256,458
Loans: Purchased credit impaired loans	149,383	179,367
Loans: Collectively evaluated for impairment	18,565,751	17,769,043
Loans receivable	19,092,504	18,204,868	$ 19,004,163
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	13,709	13,509
Allowance for loan losses: Decrease in FDIC loss share receivable
Allowance for loan losses: Ending balance	12,985	13,611
Allowance for loan losses: Individually evaluated for impairment	1,261	1,114
Allowance for loan losses: Amounts related to purchased credit impaired loans	576	213
Allowance for loan losses: Collectively evaluated for impairment	11,148	12,284
Loans: Individually evaluated for impairment	14,071	13,599
Loans: Purchased credit impaired loans	4,361	7,669
Loans: Collectively evaluated for impairment	2,376,430	2,483,836
Loans receivable	2,394,862	2,505,104	2,384,599
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	7,372	6,271
Allowance for loan losses: Decrease in FDIC loss share receivable
Allowance for loan losses: Ending balance	9,924	6,720
Allowance for loan losses: Individually evaluated for impairment	1	1
Allowance for loan losses: Amounts related to purchased credit impaired loans	173	283
Allowance for loan losses: Collectively evaluated for impairment	9,750	6,436
Loans: Individually evaluated for impairment	113	1,592
Loans: Purchased credit impaired loans	5,843	4,326
Loans: Collectively evaluated for impairment	1,407,922	1,246,749
Loans receivable	1,413,878	1,252,667	1,373,421
Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	24,844	25,361
Allowance for loan losses: Decrease in FDIC loss share receivable		(1,696)
Allowance for loan losses: Ending balance	24,918	23,806
Allowance for loan losses: Individually evaluated for impairment	276	94
Allowance for loan losses: Amounts related to purchased credit impaired loans	11,720	13,286
Allowance for loan losses: Collectively evaluated for impairment	12,922	10,426
Loans: Individually evaluated for impairment	8,338	3,236
Loans: Purchased credit impaired loans	116,409	138,260
Loans: Collectively evaluated for impairment	2,608,074	2,124,767
Loans receivable	2,732,821	2,266,263	2,690,472
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	30,503	26,142
Allowance for loan losses: Decrease in FDIC loss share receivable		(103)
Allowance for loan losses: Ending balance	22,660	26,622
Allowance for loan losses: Individually evaluated for impairment	232	199
Allowance for loan losses: Amounts related to purchased credit impaired loans	612	1,019
Allowance for loan losses: Collectively evaluated for impairment	21,816	25,404
Loans: Individually evaluated for impairment	617	2,149
Loans: Purchased credit impaired loans	5,876	9,951
Loans: Collectively evaluated for impairment	2,022,685	2,046,996
Loans receivable	2,029,178	2,059,096	2,115,295
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(18,436)	(33,944)
Allowance for loan losses: Recoveries	6,236	3,915
Allowance for loan losses: Net provision for loan losses	12,253	15,991
Non-Purchased Credit Impaired Loans [Member] | Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs		(7)
Allowance for loan losses: Recoveries	63	375
Allowance for loan losses: Net provision for loan losses	(787)	(266)
Non-Purchased Credit Impaired Loans [Member] | Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(10)	(91)
Allowance for loan losses: Recoveries	29	471
Allowance for loan losses: Net provision for loan losses	2,533	69
Non-Purchased Credit Impaired Loans [Member] | Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(192)	(348)
Allowance for loan losses: Recoveries	116	113
Allowance for loan losses: Net provision for loan losses	150	376
Non-Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(8,048)	(8,678)
Allowance for loan losses: Recoveries	1,794	1,743
Allowance for loan losses: Net provision for loan losses	5,059	7,518
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	140,880	158,135
Allowance for loan losses: Decrease in FDIC loss share receivable		(31)
Allowance for loan losses: Ending balance	140,226	142,791
Allowance for loan losses: Individually evaluated for impairment	22,831	15,093
Allowance for loan losses: Amounts related to purchased credit impaired loans	966	1,198
Allowance for loan losses: Collectively evaluated for impairment	116,429	126,500
Loans: Individually evaluated for impairment	354,231	235,882
Loans: Purchased credit impaired loans	16,894	19,161
Loans: Collectively evaluated for impairment	10,150,640	9,866,695
Loans receivable	10,521,765	10,121,738	10,440,376
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	127,918	147,052
Allowance for loan losses: Decrease in FDIC loss share receivable		(31)
Allowance for loan losses: Ending balance	126,606	131,269
Allowance for loan losses: Individually evaluated for impairment	20,356	15,017
Allowance for loan losses: Amounts related to purchased credit impaired loans	471	411
Allowance for loan losses: Collectively evaluated for impairment	105,779	115,841
Loans: Individually evaluated for impairment	323,913	231,988
Loans: Purchased credit impaired loans	8,510	6,693
Loans: Collectively evaluated for impairment	8,003,799	7,835,606
Loans receivable	8,336,222	8,074,287	8,297,937
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	12,962	11,083
Allowance for loan losses: Decrease in FDIC loss share receivable
Allowance for loan losses: Ending balance	13,620	11,522
Allowance for loan losses: Individually evaluated for impairment	2,475	76
Allowance for loan losses: Amounts related to purchased credit impaired loans	495	787
Allowance for loan losses: Collectively evaluated for impairment	10,650	10,659
Loans: Individually evaluated for impairment	30,318	3,894
Loans: Purchased credit impaired loans	8,384	12,468
Loans: Collectively evaluated for impairment	2,146,841	2,031,089
Loans receivable	2,185,543	2,047,451	$ 2,142,439
Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member] | Total Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(10,186)	(24,820)
Allowance for loan losses: Recoveries	4,234	1,213
Allowance for loan losses: Net provision for loan losses	5,298	8,294
Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(9,335)	(24,791)
Allowance for loan losses: Recoveries	4,146	938
Allowance for loan losses: Net provision for loan losses	3,877	8,101
Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(851)	(29)
Allowance for loan losses: Recoveries	88	275
Allowance for loan losses: Net provision for loan losses	$ 1,421	$ 193

Loans and Allowance for Loan 45

Loans and Allowance for Loan Losses (Composition of Nonaccrual Loans by Portfolio Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 275,179	$ 252,800
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	15,633	14,574
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	3,724	3,807
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	35,069	40,480
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	14,163	15,087
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	206,590	178,852
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	179,203	152,863
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 27,387	$ 25,989

Loans and Allowance for Loan 46

Loans and Allowance for Loan Losses (Troubled Debt Restructurings Modified by Portfolio Class) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)contract	Mar. 31, 2017USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	17	13
Pre-Modification Outstanding Recorded Investment	$ 63,220	$ 45,092
Post-Modification Outstanding Recorded Investment	$ 63,220	$ 45,092
Total Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	14	10
Pre-Modification Outstanding Recorded Investment	$ 61,391	$ 39,315
Post-Modification Outstanding Recorded Investment	$ 61,391	$ 39,315
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	1	2
Pre-Modification Outstanding Recorded Investment	$ 1,564	$ 5,527
Post-Modification Outstanding Recorded Investment	$ 1,564	$ 5,527
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	1
Pre-Modification Outstanding Recorded Investment	$ 43
Post-Modification Outstanding Recorded Investment	$ 43
Residential Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract		1
Pre-Modification Outstanding Recorded Investment		$ 250
Post-Modification Outstanding Recorded Investment		$ 250
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	1
Pre-Modification Outstanding Recorded Investment	$ 222
Post-Modification Outstanding Recorded Investment	$ 222
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	13	9
Pre-Modification Outstanding Recorded Investment	$ 55,482	$ 38,659
Post-Modification Outstanding Recorded Investment	$ 55,482	$ 38,659
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	1	1
Pre-Modification Outstanding Recorded Investment	$ 5,909	$ 656
Post-Modification Outstanding Recorded Investment	$ 5,909	$ 656

Loans and Allowance for Loan 47

Loans and Allowance for Loan Losses (Loans Individually Evaluated for Impairment Disaggregated by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	$ 126,992		$ 147,055
Recorded investment with an allowance	250,378		170,142
Unpaid principal balance	392,958		341,713
Related allowance	24,601		18,566
Average recorded investment	347,285	$ 278,903
Interest income recognized	1,691	388
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	6,055		5,101
Recorded investment with an allowance	8,016		10,429
Unpaid principal balance	14,269		15,687
Related allowance	1,261		1,326
Average recorded investment	14,801	14,487
Interest income recognized	25	43
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	100		100
Recorded investment with an allowance	13		263
Unpaid principal balance	114		363
Related allowance	1		11
Average recorded investment	238	1,766
Interest income recognized
Residential Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	5,861		8,245
Recorded investment with an allowance	2,477		2,395
Unpaid principal balance	11,682		13,855
Related allowance	276		189
Average recorded investment	9,489	3,792
Interest income recognized	5	2
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	14
Recorded investment with an allowance	603		1,292
Unpaid principal balance	718		1,294
Related allowance	232		118
Average recorded investment	955	2,152
Interest income recognized	9	2
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	114,962		133,609
Recorded investment with an allowance	239,269		155,763
Unpaid principal balance	366,175		310,514
Related allowance	22,831		16,922
Average recorded investment	321,802	256,706
Interest income recognized	1,652	341
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	108,898		116,682
Recorded investment with an allowance	215,015		151,199
Unpaid principal balance	335,178		285,685
Related allowance	20,356		16,129
Average recorded investment	295,897	251,625
Interest income recognized	1,586	337
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	6,064		16,927
Recorded investment with an allowance	24,254		4,564
Unpaid principal balance	30,997		24,829
Related allowance	2,475		$ 793
Average recorded investment	25,905	5,081
Interest income recognized	$ 66	$ 4

Loans and Allowance for Loan 48

Loans and Allowance for Loan Losses (Age Analysis of Past Due Loans by Portfolio Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 331,434	$ 327,349
Current	18,761,070	18,676,814
Total loans	19,092,504	19,004,163	$ 18,204,868
Recorded Investment > 90 Days and Accruing	26,463	27,766
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	109,136	137,267
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	30,602	33,000
Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	191,696	157,082
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,301	13,561
Current	2,383,561	2,371,038
Total loans	2,394,862	2,384,599	2,505,104
Recorded Investment > 90 Days and Accruing	2,771	489
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	928	5,315
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,954	2,165
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,419	6,081
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,068	8,581
Current	1,403,810	1,364,840
Total loans	1,413,878	1,373,421	1,252,667
Recorded Investment > 90 Days and Accruing	259	477
Total Commercial [Member] | Construction and Land Development [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,537	4,113
Total Commercial [Member] | Construction and Land Development [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	416	1,056
Total Commercial [Member] | Construction and Land Development [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,115	3,412
Total Commercial [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	223,883	191,167
Current	10,297,882	10,249,209
Total loans	10,521,765	10,440,376	10,121,738
Recorded Investment > 90 Days and Accruing	21,690	24,021
Total Commercial [Member] | Total Commercial And Industrial [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	52,773	71,259
Total Commercial [Member] | Total Commercial And Industrial [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18,612	11,409
Total Commercial [Member] | Total Commercial And Industrial [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	152,498	108,499
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	194,166	166,509
Current	8,142,056	8,131,428
Total loans	8,336,222	8,297,937	8,074,287
Recorded Investment > 90 Days and Accruing	20,330	21,989
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	45,309	62,766
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18,497	10,761
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	130,360	92,982
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	29,717	24,658
Current	2,155,826	2,117,781
Total loans	2,185,543	2,142,439	2,047,451
Recorded Investment > 90 Days and Accruing	1,360	2,032
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,464	8,493
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	115	648
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	22,138	15,517
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	57,433	74,712
Current	2,675,388	2,615,760
Total loans	2,732,821	2,690,472	2,266,263
Recorded Investment > 90 Days and Accruing	1,170	2,208
Residential Mortgages [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	32,815	33,621
Residential Mortgages [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,496	10,554
Residential Mortgages [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20,122	30,537
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	28,749	39,328
Current	2,000,429	2,075,967
Total loans	2,029,178	2,115,295	$ 2,059,096
Recorded Investment > 90 Days and Accruing	573	571
Consumer [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	16,083	22,959
Consumer [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,124	7,816
Consumer [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 7,542	$ 8,553

Loans and Allowance for Loan 49

Loans and Allowance for Loan Losses (Credit Quality Indicators by Segments and Portfolio Class) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 14,330,505	$ 14,198,396
Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,807,913	12,601,853
Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	438,813	520,230
Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	151,599	126,137
Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	932,162	950,111
Total Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	18	65
Residential Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,732,821	2,690,472
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,029,178	2,115,295
Residential Mortgage and Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,761,999	4,805,767
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,394,862	2,384,599
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,268,358	2,223,245
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	58,092	83,444
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,344	13,244
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	59,068	64,658
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans		8
Construction and Land Development [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,413,878	1,373,421
Construction and Land Development [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,334,456	1,291,638
Construction and Land Development [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	59,208	60,804
Construction and Land Development [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	6,279	4,788
Construction and Land Development [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	13,935	16,191
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,521,765	10,440,376
Total Commercial And Industrial [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,205,099	9,086,970
Total Commercial And Industrial [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	321,513	375,982
Total Commercial And Industrial [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	135,976	108,105
Total Commercial And Industrial [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	859,159	869,262
Total Commercial And Industrial [Member] | Total Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	18	57
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,336,222	8,297,937
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,250,715	7,190,604
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	269,657	293,069
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	100,005	80,649
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	715,827	733,558
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	18	57
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,185,543	2,142,439
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,954,384	1,896,366
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	51,856	82,913
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	35,971	27,456
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	143,332	135,704
Performing [Member] | Residential Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,696,582	2,647,784
Performing [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,014,442	2,099,637
Performing [Member] | Residential Mortgage and Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,711,024	4,747,421
Nonperforming [Member] | Residential Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	36,239	42,688
Nonperforming [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,736	15,658
Nonperforming [Member] | Residential Mortgage and Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 50,975	$ 58,346

Loans and Allowance for Loan 50

Loans and Allowance for Loan Losses (Changes in Carrying Amount of Purchased Credit Impaired Loans and Related Accretable Yield) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Loans and Allowance for Loan Losses [Abstract]
Carrying Amount of Loans, Balance at beginning of period	$ 153,403	$ 190,915
Carrying Amount of Loans, Payments received, net	(8,288)	(69,591)
Carrying Amount of Loans, Accretion	4,268	17,079
Carrying Amount of Loans, Balance at end of period	149,383	153,403
Accretable Yield, Balance at beginning of period	62,517	113,686
Accretable Yield, Payments received, net	(1,703)	(7,412)
Accretable Yield, Accretion	(4,268)	(17,079)
Accretable Yield, Increase (decrease) in expected cash flows based on actual cash flow and changes in cash flow assumptions	(956)	(30,379)
Accretable Yield, Net transfers from nonaccretable difference to accretable yield		3,701
Accretable Yield, Balance at end of period	$ 55,590	$ 62,517

Securities Sold under Agreeme51

Securities Sold under Agreements to Repurchase (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Securities Sold under Agreements to Repurchase [Abstract]
Securities sold under agreements to repurchase	$ 443.2	$ 430.6

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)item	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Derivative [Line Items]
Notional amount of derivatives	$ 2,849,743		$ 2,799,296
Deposits	26,959	$ 12,819
Cash Flow Hedge [Member]
Derivative [Line Items]
Impact to interest income from cash flow hedges	(600)	100
Fair Value Hedging [Member]
Derivative [Line Items]
Impact to interest income of the fair value hedges	100	(100)
Derivatives Designated as Hedging Instruments [Member]
Derivative [Line Items]
Notional amount of derivatives	1,358,110		1,358,110
Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative income reflected in income statement	1,500	$ 500
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member]
Derivative [Line Items]
Notional amount of derivatives	875,000		875,000
Termination fees	10,600
Amortization of accumulated other comprehensive loss on terminated cash flow hedges	$ 1,000
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member] | Swap Agreement One To Five [Member]
Derivative [Line Items]
Number of interest rate swap agreements | item	5
Number of interest rate swap terminated | item	5
Notional amount of derivatives	$ 450,000
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member] | Date One [Member] | Swap Agreement 1, Expires 2022 [Member]
Derivative [Line Items]
Notional amount of derivatives	$ 425,000
Derivative maturity expiration year	2,022
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member] | Date Two [Member] | Swap Agreement 2, Expires 2023 [Member]
Derivative [Line Items]
Notional amount of derivatives	$ 350,000
Derivative maturity expiration year	2,023
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member] | Date Three [Member] | Swap Agreement 3, Expires 2024 [Member]
Derivative [Line Items]
Notional amount of derivatives	$ 100,000
Derivative maturity expiration year	2,024
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of derivatives	$ 483,110		$ 483,110

Derivatives (Fair Values of Der

Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2018		Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		$ 2,849,743		$ 2,799,296
Fair Values, Assets		4,508		2,148
Fair Values, Liabilities		1,584		3,938
Less: netting adjustment, Assets	[1]	(14,081)		(4,913)
Less: netting adjustment, Liabilities	[1]	(19,162)	[2]	(21,563)
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		1,358,110		1,358,110
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		1,491,633		1,441,186
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	[3]	1,184,109		1,144,789
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		121,479		119,951
Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		81,326		80,462
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		61,904		53,724
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		42,815		42,260
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		26,764		19,070
Total derivative assets/liabilities		12,683		14,157
Other Assets [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		1,752
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		25,012		19,070
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets	[3]	20,680		15,408
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		13		23
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		847		1,000
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		376		186
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		3,096		2,453
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		41,691	[2]	35,952
Total derivative assets/liabilities		22,529	[2]	14,389
Other Liabilities [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		16,615	[2]	16,495
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		25,076	[2]	19,457
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[3]	20,710	[2]	15,857
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		61	[2]	109
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		454	[2]	290
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		789	[2]	782
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		3,062	[2]	2,419
Cash Flow Hedge [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		875,000		875,000
Cash Flow Hedge [Member] | Other Assets [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		1,752
Cash Flow Hedge [Member] | Other Liabilities [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities		12,667	[2]	14,020
Fair Value Hedging [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		483,110		483,110
Fair Values, Liabilities		$ 3,948	[2]	$ 2,475
[1]	Represents balance sheet netting of derivative assets and liabilities for variation margin collateral held or placed with the same central clearing counterparty. See offsetting assets and liabilities for further information.
[2]	March 31, 2018December 31, 2017Derivative (1)Derivative (1)(in thousands)Type of HedgeNotional or Contractual AmountAssetsLiabilitiesNotional or Contractual AmountAssetsLiabilitiesDerivatives designated as hedging instruments:Interest rate swapsCash Flow$ 875,000 $ 1,752 $ 12,667 $ 875,000 $ -$ 14,020 Interest rate swapsFair Value 483,110 - 3,948 483,110 - 2,475 $ 1,358,110 $ 1,752 $ 16,615 $ 1,358,110 $ -$ 16,495 Derivatives not designated as hedging instruments:Interest rate swaps (2)N/A$ 1,184,109 $ 20,680 $ 20,710 $ 1,144,789 $ 15,408 $ 15,857 Risk participation agreementsN/A 121,479 13 61 119,951 23 109 Forward commitments to sell residential mortgage loansN/A 81,326 847 454 80,462 1,000 290 Interest rate-lock commitments on residential mortgage loansN/A 61,904 376 789 53,724 186 782 Foreign exchange forward contractsN/A 42,815 3,096 3,062 42,260 2,453 2,419 1,491,633 25,012 25,076 1,441,186 19,070 19,457 Total derivatives$ 2,849,743 $ 26,764 $ 41,691 $ 2,799,296 $ 19,070 $ 35,952 Less: netting adjustment (3) (14,081) (19,162) (4,913) (21,563)Total derivative assets/liabilities$ 12,683 $ 22,529 $ 14,157 $ 14,389 Derivative assets and liabilities are reported at fair value in other assets or other liabilities, respectively, in the consolidated balance sheets.
[3]	The notional amount represents both the customer accommodation agreements and offsetting agreements with unrelated financial institutions.

Derivatives (Offsetting Derivat

Derivatives (Offsetting Derivative Assets and Liabilities Subject to Master Netting Arrangements) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives [Abstract]
Gross Amounts Recognized, Derivative Assets	$ 18,822	$ 7,155
Gross Amounts Offset in the Statement of Income, Derivative Assets	(14,314)	(5,007)
Net Amounts Presented in the Statement of Income, Derivative Assets	4,508	2,148
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Assets	1,517	2,148
Gross Amounts Not offset in the Statement of Income - Cash Collateral, Derivative Assets
Net Amounts Presented in the Statement of Income, Derivative Assets	2,991
Gross Amounts Recognized, Derivative Liabilities	18,081	24,015
Gross Amounts Offset in the Statement of Income, Derivative Liabilities	(16,497)	(20,077)
Net Amounts Presented in the Statement of Income, Derivative Liabilities	1,584	3,938
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Liabilities	1,517	2,148
Gross Amounts Not offset in the Statement of Income - Cash Collateral, Derivative Liabilities	4,770	4,099
Net Amounts Presented in the Statement of Income, Derivative Liabilities	$ (4,703)	$ (2,309)

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Equity, Class of Treasury Stock [Line Items]
Treasury stock shares	1.1	1.2
Treasury stock, Cost basis	$ 24.4	$ 25.5
Restricted Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares nonvested	1.5	1.5

Stockholders' Equity (Component

Stockholders' Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		$ (134,402)	$ (120,532)
Net change in unrealized gain (loss)		(62,244)	1,184
Reclassification of net (gain) loss realized and included in earnings		1,796	1,387
Amortization of unrealized net loss on securities transferred to HTM		755	650
Income tax expense (benefit)		(13,546)	1,201
Ending Balance		(180,549)	(118,512)
Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(29,512)	(28,679)
Net change in unrealized gain (loss)		(55,114)	2,319
Income tax expense (benefit)		(12,508)	843
Ending Balance		(72,118)	(27,203)
HTM Securities Transferred from AFS [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(14,585)	(14,392)
Amortization of unrealized net loss on securities transferred to HTM		755	650
Income tax expense (benefit)		171	266
Ending Balance		(14,001)	(14,008)
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(79,078)	(72,501)
Reclassification of net (gain) loss realized and included in earnings		1,177	1,387
Income tax expense (benefit)		267	504
Ending Balance		(78,168)	(71,618)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(11,227)	(4,960)
Net change in unrealized gain (loss)		(7,130)	(1,135)
Reclassification of net (gain) loss realized and included in earnings		619
Income tax expense (benefit)		(1,476)	(412)
Ending Balance		(16,262)	(5,683)
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Valuation adjustment for pension plan amendment	[1],[2]	$ (1,177)	$ (1,387)
[1]	These AOCI components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 12 - Retirement Plans for additional details).
[2]	Three Months EndedAmount reclassified from AOCI (a) March 31,Affected line item on(in thousands)20182017the statement of incomeAmortization of unrealized net loss on securities transferred to HTM (755) (650)Interest incomeTax effect 171 266Income taxesNet of tax (584) (384)Net incomeAmortization of defined benefit pension and post-retirement items (1,177) (1,387)Other noninterest expense (b)Tax effect 267 504Income taxesNet of tax (910) (883)Net incomeReclassification of unrealized gain on cash flow hedges 336 -Interest incomeTax effect (76) -Income taxesNet of tax 260Net incomeAmortization of loss on terminated cash flow hedges (954) -Interest incomeTax effect 216 -Income taxesNet of tax (738) -Net incomeTotal reclassifications, net of tax$ (1,972)$ (1,267)Net incomeAmounts in parenthesis indicate reduction in net income.

Stockholders' Equity (Line Item

Stockholders' Equity (Line Items in Consolidated Income Statements Affected by Amounts Reclassified from Accumulated Other Comprehensive Income) (Details) - Amount Reclassified from Accumulated Other Comprehensive Income [Member] - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications, net of tax	[1]	$ (1,972)	$ (1,267)
HTM Securities Transferred from AFS [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of unrealized net loss on securities transferred to HTM	[1]	(755)	(650)
Tax effect	[1]	171	266
Net of tax	[1]	(584)	(384)
Employee Benefit Plans [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension and post-retirement items	[1],[2]	(1,177)	(1,387)
Tax effect	[1]	267	504
Net of tax	[1]	(910)	$ (883)
Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification of unrealized gain on cash flow hedges	[1]	336
Tax effect	[1]	(76)
Net of tax	[1]	260
Amortization of loss on terminated cash flash hedges	[1]	(954)
Tax effect	[1]	216
Net of tax	[1]	$ (738)
[1]	Three Months EndedAmount reclassified from AOCI (a) March 31,Affected line item on(in thousands)20182017the statement of incomeAmortization of unrealized net loss on securities transferred to HTM (755) (650)Interest incomeTax effect 171 266Income taxesNet of tax (584) (384)Net incomeAmortization of defined benefit pension and post-retirement items (1,177) (1,387)Other noninterest expense (b)Tax effect 267 504Income taxesNet of tax (910) (883)Net incomeReclassification of unrealized gain on cash flow hedges 336 -Interest incomeTax effect (76) -Income taxesNet of tax 260Net incomeAmortization of loss on terminated cash flow hedges (954) -Interest incomeTax effect 216 -Income taxesNet of tax (738) -Net incomeTotal reclassifications, net of tax$ (1,972)$ (1,267)Net incomeAmounts in parenthesis indicate reduction in net income.
[2]	These AOCI components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 12 - Retirement Plans for additional details).

Other Noninterest Income (Detai

Other Noninterest Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Noninterest Income [Abstract]
Income from bank-owned life insurance	$ 3,070	$ 2,652
Credit-related fees	2,722	2,878
Income from derivatives	1,523	465
Gain (loss) on sale of assets	(1,207)	4,125
Amortization of loss share receivable		(1,100)
Other miscellaneous	3,377	2,755
Total other noninterest income	$ 9,485	$ 11,775

Other Noninterest Expense (Deta

Other Noninterest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Noninterest Expense [Abstract]
Advertising	$ 2,526	$ 3,077
Corporate value and franchise taxes	3,440	3,036
Printing and supplies	1,286	1,178
Travel expense	1,066	1,059
Entertainment and contributions	2,518	1,783
Tax credit investment amortization	874	1,212
Other retirement expense	(4,463)	(3,060)
Other miscellaneous	5,684	7,285
Total other noninterest expense	$ 12,931	$ 15,570

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Weighted-average anti-dilutive potential common shares	0	15,986

Earnings Per Share (Computation

Earnings Per Share (Computation of Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Net income to common shareholders	$ 72,475	$ 49,014
Net income allocated to participating securities - basic and diluted	1,366	1,156
Net income allocated to common shareholders - basic and diluted	$ 71,109	$ 47,858
Weighted-average common shares - basic	85,241	84,365
Dilutive potential common shares	182	259
Weighted-average common shares - diluted	85,423	84,624
Earnings per common share: Basic	$ 0.83	$ 0.57
Earnings per common share: Diluted	$ 0.83	$ 0.57

Retirement Plans (Narrative) (D

Retirement Plans (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018	Jun. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Newly eligible associates initial savings rate	3.00%
Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Period of employment for eligibility	3 years
Additional matching percentage	2.00%
First 1% Of Contribution Saved [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage	100.00%
Percentage of compensation saved	1.00%
Next 5% Of Contribution Saved [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage	50.00%
Percentage of compensation saved	5.00%
2% Of Contribution [Member] | Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage		2.00%
4% Of Contribution [Member] | Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage		4.00%
6% Of Contribution [Member] | Amended Hancock 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching percentage		6.00%

Retirement Plans (Components of

Retirement Plans (Components of Net Periodic Benefits Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,925	$ 3,750
Interest cost	3,923	4,123
Expected return on plan assets	(9,700)	(8,750)
Amortization of net loss/ prior service cost	1,326	1,435
Net periodic benefit cost	(1,526)	558
Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	35	48
Interest cost	137	180
Amortization of net loss/ prior service cost	(149)	(48)
Net periodic benefit cost	$ 23	$ 180

Share-Based Payment Arrangeme64

Share-Based Payment Arrangements (Narrative) (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018USD ($)entity$ / sharesshares	Mar. 31, 2017USD ($)
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised | $	$ 0.5	$ 3.3
Restricted and Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense | $	$ 47.5
Weighted-average period	3 years 3 months 18 days
Total fair value of shares vested | $	$ 0.3	$ 0.5
Shares granted | shares	54,710
Grant date fair value per share | $ / shares	$ 48.22
Executive Management [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Executive Management [Member] | Performance Shares [Member] | Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted | shares	26,147
Grant date fair value per share | $ / shares	$ 51.13
Vesting performance period	3 years
Number of peer group regional banks | entity	43
Executive Management [Member] | Performance Shares [Member] | Core Earnings Per Share [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted | shares	26,147
Grant date fair value per share | $ / shares	$ 44.84
Vesting performance period	2 years
Executive Management [Member] | Tranche One [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of maximum number of shares vested	200.00%

Share-Based Payment Arrangeme65

Share-Based Payment Arrangements (Summary of Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value, Cancelled/Forfeited
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at Beginning	88,301
Number of Shares, Exercised/Released	(24,793)
Number of Shares, Cancelled/Forfeited
Number of Shares, Expired
Number of Shares, Outstanding at Ending	63,508	88,301
Number of Shares, Exercisable at Ending	63,508
Weighted Average Exercise Price, Outstanding at Beginning	$ 34.84
Weighted Average Exercise Price, Exercised/Released	35.12
Weighted Average Exercise Price, Cancelled/Forfeited
Weighted Average Exercise Price, Expired
Weighted Average Exercise Price, Outstanding at Ending	34.73	$ 34.84
Weighted Average Exercise Price, Exercisable at Ending	$ 34.73
Weighted Average Remaining Contractual Term (Years)	2 years 7 months 6 days	2 years 9 months 18 days
Weighted Average Remaining Contractual Term (Years), Exercisable at Ending	2 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding at Beginning	$ 1,294
Aggregate Intrinsic Value, Exercised/Released	495
Aggregate Intrinsic Value, Outstanding at Ending	1,078	$ 1,294
Aggregate Intrinsic Value, Exercisable at Ending	$ 1,078

Share-Based Payment Arrangeme66

Share-Based Payment Arrangements (Summary of Nonvested Restricted and Performance Shares) (Details) - Restricted and Performance Shares [Member]	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Nonvested at Beginning | shares	1,708,942
Number of Shares, Granted | shares	54,710
Number of Shares, Vested | shares	(9,587)
Number of Shares, Forfeited | shares	(30,376)
Number of Shares, Nonvested at Ending | shares	1,723,689
Weighted Average Grant Date Fair Value, Nonvested at Beginning | $ / shares	$ 37.05
Weighted Average Grant Date Fair Value, Granted | $ / shares	48.22
Weighted Average Grant Date Fair Value, Vested | $ / shares	35.90
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	35.25
Weighted Average Grant Date Fair Value, Nonvested at Ending | $ / shares	$ 37.44

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - Recurring [Member] - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Transfers of assets and liabilities between level 1, 2, 3	$ 0	$ 0
Investment Securities [Member] | Minimum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Targeted duration	2 years
Investment Securities [Member] | Maximum [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Targeted duration	5 years

Fair Value Measurements (Financ

Fair Value Measurements (Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	$ 2,915,648	$ 2,910,869
Derivative assets	4,508	2,148
Derivative liabilities	1,584	3,938
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	2,915,648	2,910,869
Derivative assets	12,682	14,157
Total recurring fair value measurements - assets	2,928,330	2,925,026
Derivative liabilities	22,529	14,389
Total recurring fair value measurements - liabilities	22,529	14,389
Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	2,915,648	2,910,869
Derivative assets	12,682	14,157
Total recurring fair value measurements - assets	2,928,330	2,925,026
Derivative liabilities	22,529	14,389
Total recurring fair value measurements - liabilities	22,529	14,389
Recurring [Member] | U.S. Treasury And Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	93,884	97,272
Recurring [Member] | U.S. Treasury And Government Agency Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	93,884	97,272
Recurring [Member] | Municipal Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	237,291	243,786
Recurring [Member] | Municipal Obligations [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	237,291	243,786
Recurring [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	5,500	3,500
Recurring [Member] | Corporate Debt Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	5,500	3,500
Recurring [Member] | Residential Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	1,743,543	1,715,213
Recurring [Member] | Residential Mortgage-Backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	1,743,543	1,715,213
Recurring [Member] | Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	680,272	687,135
Recurring [Member] | Commercial Mortgage-Backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	680,272	687,135
Recurring [Member] | Collateralized Mortgage Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	155,158	163,963
Recurring [Member] | Collateralized Mortgage Obligations [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities	$ 155,158	$ 163,963

Fair Value Measurements (Fina69

Fair Value Measurements (Financial Assets Measured at Fair Value on Nonrecurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	$ 205,945	$ 184,205
Other real estate owned	5,493	6,928
Total nonrecurring fair value measurements	211,438	191,133
Nonrecurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans
Other real estate owned
Total nonrecurring fair value measurements
Nonrecurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans	205,945	184,205
Total nonrecurring fair value measurements	205,945	184,205
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	5,493	6,928
Total nonrecurring fair value measurements	$ 5,493	$ 6,928

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities	$ 2,915,648	$ 2,910,869
Held to maturity securities	3,014,428	2,977,511
Derivative financial instruments	4,508	2,148
Derivative financial instruments	1,584	3,938
Total Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	315,401	479,332
Available for sale debt securities	2,915,648	2,910,869
Held to maturity securities	2,952,295	2,962,010
Loans, net	18,543,715	18,587,508
Loans held for sale	21,827	39,865
Derivative financial instruments	12,682	14,157
Deposits	22,438,772	22,238,847
Federal funds purchased	25,967	140,754
Securities sold under agreements to repurchase	443,151	430,569
Short-term FHLB Borrowings	982,979	1,132,567
Long-term debt	297,555	303,631
Derivative financial instruments	22,529	14,389
Total Fair Value [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	315,401	479,332
Federal funds purchased	25,967	140,754
Securities sold under agreements to repurchase	443,151	430,569
Short-term FHLB Borrowings	982,979	1,132,567
Total Fair Value [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities	2,915,648	2,910,869
Held to maturity securities	2,952,295	2,962,010
Loans, net	205,945	184,205
Loans held for sale	21,827	39,865
Derivative financial instruments	12,682	14,157
Long-term debt	297,555	303,631
Derivative financial instruments	22,529	14,389
Total Fair Value [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	18,337,770	18,403,303
Deposits	22,438,772	22,238,847
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash, interest-bearing bank deposits, and federal funds sold	315,401	479,332
Available for sale debt securities	2,915,648	2,910,869
Held to maturity securities	3,014,428	2,977,511
Loans, net	18,881,791	18,786,855
Loans held for sale	21,827	39,865
Derivative financial instruments	12,682	14,157
Deposits	22,485,722	22,253,202
Federal funds purchased	25,967	140,754
Securities sold under agreements to repurchase	443,151	430,569
Short-term FHLB Borrowings	982,979	1,132,567
Long-term debt	300,443	305,513
Derivative financial instruments	$ 22,529	$ 14,389