Hancock Whitney Corporation - 6 (HWC) 10-Q 8 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	HANCOCK WHITNEY CORP
Entity Filer Category	Large Accelerated Filer
Entity Central Index Key	750,577
Trading Symbol	hwc
Amendment Flag	false
Document Type	10-Q
Document Fiscal Period Focus	Q2
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		85,340,233

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 355,072	$ 386,948
Interest-bearing bank deposits	103,763	92,157
Federal funds sold	447	227
Securities available for sale, at fair value (amortized cost of $3,091,620 and $2,949,057)	2,981,673	2,910,869
Securities held to maturity (fair value of $3,054,469 and $2,962,010)	3,132,200	2,977,511
Loans held for sale	36,047	39,865
Loans	19,370,917	19,004,163
Less: allowance for loan losses	(214,530)	(217,308)
Loans, net	19,156,387	18,786,855
Property and equipment, net of accumulated depreciation of $218,526 and $214,998	336,513	333,663
Prepaid expenses	31,232	28,015
Other real estate, net	9,675	14,862
Accrued interest receivable	80,982	82,191
Goodwill	745,523	745,523
Other intangible assets, net	79,700	90,640
Life insurance contracts	546,395	541,081
Deferred tax asset, net	53,510	53,979
Other assets	276,328	251,700
Total assets	27,925,447	27,336,086
Deposits
Noninterest-bearing	8,165,796	8,307,497
Interest-bearing	14,069,542	13,945,705
Total deposits	22,235,338	22,253,202
Short-term borrowings	2,314,190	1,703,890
Long-term debt	266,009	305,513
Accrued interest payable	14,145	8,680
Other liabilities	166,210	179,852
Total liabilities	24,995,892	24,451,137
Stockholders' equity:
Common Stock	292,716	292,716
Capital surplus	1,729,542	1,718,117
Retained earnings	1,110,506	1,008,518
Accumulated other comprehensive loss, net	(203,209)	(134,402)
Total stockholders' equity	2,929,555	2,884,949
Total liabilities and stockholders' equity	$ 27,925,447	$ 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	85,335	85,200

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Consolidated Balance Sheets [Abstract]
Securities available for sale, amortized cost	$ 3,091,620	$ 2,949,057
Securities held to maturity, fair value	3,054,469	2,962,010
Property and equipment, accumulated depreciation	$ 218,526	$ 214,998
Common shares, 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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest income:
Loans, including fees	$ 215,161	$ 194,180	$ 421,008	$ 366,961
Loans held for sale	295	236	516	453
Securities-taxable	30,783	24,402	60,084	47,769
Securities-tax exempt	5,490	5,628	11,027	11,035
Short-term investments	575	1,731	1,064	2,474
Total interest income	252,304	226,177	493,699	428,692
Interest expense:
Deposits	29,870	18,364	56,829	31,183
Short-term borrowings	7,416	4,232	12,767	7,173
Long-term debt	3,471	3,864	6,892	8,928
Total interest expense	40,757	26,460	76,488	47,284
Net interest income	211,547	199,717	417,211	381,408
Provision for loan losses	8,891	14,951	21,144	30,942
Net interest income after provision for loan losses	202,656	184,766	396,067	350,466
Noninterest income:
Service charges on deposit accounts	20,981	20,061	42,429	39,267
Trust fees	11,653	11,506	22,988	22,717
Bank card and ATM fees	15,464	13,687	29,922	26,155
Investment and annuity fees and insurance commissions	6,264	6,445	12,389	11,709
Secondary mortgage market operations	3,965	4,241	7,366	7,808
Other income	10,505	11,547	19,990	23,322
Total noninterest income	68,832	67,487	135,084	130,978
Noninterest expense:
Compensation expense	79,885	82,145	159,985	155,244
Employee benefits	17,358	18,888	37,232	37,968
Personnel expense	97,243	101,033	197,217	193,212
Net occupancy expense	12,316	13,080	23,326	23,837
Equipment expense	4,262	3,964	7,808	7,678
Data processing expense	18,273	16,798	34,722	32,195
Professional services expense	13,381	10,353	22,636	21,629
Amortization of intangible assets	5,322	5,757	10,940	10,462
Telecommunications and postage	3,615	3,738	7,465	7,205
Deposit insurance and regulatory fees	8,376	6,983	16,324	13,473
Other real estate income	(289)	(2,515)	(79)	(2,528)
Other expense	21,903	24,279	34,834	39,849
Total noninterest expense	184,402	183,470	355,193	347,012
Income before income taxes	87,086	68,783	175,958	134,432
Income taxes	15,909	16,516	32,306	33,151
Net income	$ 71,177	$ 52,267	$ 143,652	$ 101,281
Earnings per common share-basic	$ 0.82	$ 0.60	$ 1.65	$ 1.17
Earnings per common share-diluted	0.82	0.60	1.65	1.17
Dividends paid per share	$ 0.24	$ 0.24	$ 0.48	$ 0.48
Weighted average shares outstanding-basic	85,305	84,614	85,273	84,489
Weighted average shares outstanding-diluted	85,483	84,867	85,451	84,755

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 71,177	$ 52,267	$ 143,652	$ 101,281
Other comprehensive income/loss before income taxes:
Net change in unrealized gain/loss on securities available for sale and cash flow hedges	(23,409)	12,661	(85,653)	13,845
Reclassification of net losses realized and included in earnings	2,217	1,718	4,013	3,105
Valuation adjustment for pension plan amendment		17,315		17,315
Other Valuation adjustment for employee benefit plans	(9,039)	(10,782)	(9,039)	(10,782)
Amortization of unrealized net loss on securities transferred to held to maturity	925	1,099	1,680	1,749
Other comprehensive income/loss before income taxes	(29,306)	22,011	(88,999)	25,232
Income tax expense (benefit)	(6,646)	7,938	(20,192)	9,139
Other comprehensive income/loss net of income taxes	(22,660)	14,073	(68,807)	16,093
Comprehensive income	$ 48,517	$ 66,340	$ 74,845	$ 117,374

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ 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			101,281		101,281
Other comprehensive income				16,093	16,093
Comprehensive income			101,281	16,093	117,374
Cash dividends declared ($0.48 per common share)			(41,594)		(41,594)
Common stock activity, long-term incentive plan		16,801	83		16,884
Issuance of stock from dividend reinvestment and stock repurchase plan		1,530			1,530
Balance at Jun. 30, 2017	$ 291,358	1,716,584	910,459	(104,439)	2,813,962
Balance, Shares Issued at Jun. 30, 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
Net income			143,652		$ 143,652
Other comprehensive income				(68,807)	(68,807)
Comprehensive income			143,652	(68,807)	74,845
Cash dividends declared ($0.48 per common share)			(41,775)		(41,775)
Common stock activity, long-term incentive plan		9,779	111		9,890
Issuance of stock from dividend reinvestment and stock repurchase plan		1,646			1,646
Balance at Jun. 30, 2018	$ 292,716	$ 1,729,542	$ 1,110,506	$ (203,209)	$ 2,929,555
Balance, Shares Issued at Jun. 30, 2018	87,903				87,903

Consolidated Statements of Cha7

Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Retained Earnings [Member]
Cash dividends declared, per common share	$ 0.48	$ 0.48

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 143,652	$ 101,281
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,019	13,960
Provision for loan losses	21,144	30,942
Gain on other real estate owned	(266)	(2,408)
Deferred tax expense	21,361	5,415
Increase in cash surrender value of life insurance contracts	(2,621)	(7,430)
Loss on disposal of other assets	1,501	1,455
Loss on sale of business	1,145
Net decrease in loans held for sale	4,299	8,177
Net amortization of securities premium/discount	16,913	14,944
Amortization of intangible assets	10,940	10,462
Amortization of FDIC indemnification asset		2,427
Stock-based compensation expense	9,821	8,360
Decrease in interest payable and other liabilities	(22,397)	(24,405)
Net payments to FDIC for loss share claims		(935)
Decrease in FDIC loss share receivable		8,613
Decrease in payable to FDIC for loan servicing	(11,113)
Decrease in other assets	13,074	8,259
Other, net	(307)	3,595
Net cash provided by operating activities	220,165	182,712
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale		213,877
Proceeds from maturities of securities available for sale	168,186	157,290
Purchases of securities available for sale	(318,786)	(425,096)
Proceeds from maturities of securities held to maturity	178,625	174,662
Purchases of securities held to maturity	(340,508)	(554,442)
Net (increase) decrease in short-term investments	(11,826)	317,042
Proceeds from sale of loans	32,003	33,279
Net increase in loans	(504,866)	(419,102)
Purchase of life insurance contracts	(1,601)	(50,000)
Purchases of property and equipment	(18,116)	(12,649)
Proceeds from sales of property and equipment	42	16
Proceeds from sales of other real estate	8,010	12,311
Cash received in excess of cash paid for acquisitions		475,659
Proceeds from the sale of business, net of cash sold	77,648
Other, net	(34,241)	(38,414)
Net cash used in investing activities	(765,430)	(115,567)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposits	(17,746)	90,040
Net increase (decrease) in short-term borrowings	610,300	(11,134)
Repayments of long-term debt	(39,817)	(121,837)
Net proceeds from issuance of long-term debt	83	83
Dividends paid	(41,775)	(41,594)
Payroll tax remitted on net share settlement of equity awards	(415)	(3,124)
Proceeds from exercise of stock options	1,113	11,427
Proceeds from dividend reinvestment and stock purchase plans	1,646	1,530
Net cash provided by (used in) financing activities	513,389	(74,609)
NET DECREASE IN CASH AND DUE FROM BANKS	(31,876)	(7,464)
CASH AND DUE FROM BANKS, BEGINNING	386,948	372,689
CASH AND DUE FROM BANKS, ENDING	355,072	365,225
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 2,911	$ 2,855

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Basis of Presentation [Abstract]
Basis of Presentation	HANCOCK WHITNEY CORPORATION AND SUBSIDIARIES NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS  1. Basis of Presentation The consolidated financial statements include the accounts of Hancock Whitney Corporation 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. On May 25, 2018, the Company changed its name from Hancock Holding Company to Hancock Whitney Corporation, and its wholly- owned banking subsidiary changed its name from Whitney Bank to Hancock Whitney Bank. In connection with the name change, the Company changed its stock ticker symbol from “HBHC” to “HWC” on the NASDAQ Global Select Market. 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 16 – Recent Accounting Pronouncements for a discussion of accounting standards adopted during the six months ended June 30, 2018.

Acquisitions and Divestiture

Acquisitions and Divestiture	6 Months Ended
	Jun. 30, 2018
Acquisitions and Divestiture [Abstract]
Acquisitions and Divestiture	2. Acquisitions and Divestiture  On March 10, 2017, the Company , through its banking subsidiary, Hancock Whitney Bank (“Hancock Whitney”), acquired certain assets and assumed certain liabilities, including nine branches, from First NBC Bank (“FNBC”), referred to as the FNBC I transaction. Hancock 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. Hancock Whitney entered into a purchase and assumption agreement with the FDIC , referred to as the FNBC II transaction . Pursuant to the agreement, Hancock Whitney acquired selected assets and assumed selected liabilities of the former FNBC , including substantially all of the transaction and savings deposits. Hancock 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 Hancock Whitney against certain liabilities of FNBC and its affiliates not assumed or otherwise purchased by Hancock Whitney. Neither the Company nor Hancock Whitney acquired any assets, common stock, preferred stock or debt, or assume d any other obligations, of First NBC Bank Holding Company.  Subsequent to the balance sheet date, on July 13, 2018, the Company acquired the bank-managed high net worth individual and institutional investment management and trust business of Capital One, National Association ( “ Capital One ” ). The transaction added assets under management of $4 billion and assets under management and administration of $10.4 billion to the Company’s existing trust and asset management business. In addition, the Company assumed approximately $217 million of customer deposit liabilities.  On March 9, 2018, the Company sold its consumer finance subsidiary, Harrison Finance Company (“HFC”). The Company received cash of approximately $78. 9 million and recorded a loss on the sale of $1.1 million. 

Securities

Securities	6 Months Ended
	Jun. 30, 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) June 30, 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 $ 95,469 — 4,484 90,985 $ 99,535 $ — $ 2,263 $ 97,272  Municipal obligations 244,365 165 8,520 236,010 245,997 1,135 3,346 243,786  Residential mortgage-backed securities 1,826,589 2,609 54,327 1,774,871 1,729,989 5,611 20,387 1,715,213  Commercial mortgage-backed securities 770,769 153 41,390 729,532 704,518 480 17,863 687,135  Collateralized mortgage obligations 150,928 — 4,153 146,775 165,518 4 1,559 163,963  Corporate debt securities 3,500 — — 3,500 3,500 — — 3,500  $ 3,091,620 $ 2,927 $ 112,874 $ 2,981,673 $ 2,949,057 $ 7,230 $ 45,418 $ 2,910,869      Securities Held to Maturity  (in thousands) June 30, 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 — 668 49,332 $ 50,000 $ — $ 289 $ 49,711  Municipal obligations 704,082 953 14,166 690,869 723,094 8,323 4,245 727,172  Residential mortgage-backed securities 665,846 194 14,730 651,310 725,748 4,175 2,690 727,233  Commercial mortgage-backed securities 357,680 153 14,581 343,252 317,185 40 3,915 313,310  Collateralized mortgage obligations 1,354,592 18 34,904 1,319,706 1,161,484 572 17,472 1,144,584  $ 3,132,200 $ 1,318 $ 79,049 $ 3,054,469 $ 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 June 30, 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 $ 5,073 $ 5,088  Due after one year through five years 57,191 57,118  Due after five years through ten years 1,279,427 1,225,729  Due after ten years 1,749,929 1,693,738  Total available for sale debt securities $ 3,091,620 $ 2,981,673   Debt Securities Held to Maturity Amortized Fair  (in thousands) Cost Value  Due in one year or less $ 17,258 $ 17,413  Due after one year through five years 137,093 135,198  Due after five years through ten years 1,474,871 1,436,090  Due after ten years 1,502,978 1,465,768  Total held to maturity securities $ 3,132,200 $ 3,054,469 The Company held no securities c lassified as trading at June 30, 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  June 30, 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 $ 42,423 $ 1,812 $ 48,562 $ 2,672 $ 90,985 $ 4,484  Municipal obligations 54,121 984 168,133 7,536 222,254 8,520  Residential mortgage-backed securities 559,924 8,483 1,066,016 45,844 1,625,940 54,327  Commercial mortgage-backed securities 291,635 10,839 396,809 30,551 688,444 41,390  Collateralized mortgage obligations 115,891 3,007 30,884 1,146 146,775 4,153  $ 1,063,994 $ 25,125 $ 1,710,404 $ 87,749 $ 2,774,398 $ 112,874       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  June 30, 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 $ — $ — $ 49,332 $ 668 $ 49,332 $ 668  Municipal obligations 364,751 5,081 220,575 9,085 585,326 14,166  Residential mortgage-backed securities 383,695 7,189 211,897 7,541 595,592 14,730  Commercial mortgage-backed securities 232,031 9,079 70,133 5,502 302,164 14,581  Collateralized mortgage obligations 592,423 8,113 677,684 26,791 1,270,107 34,904  $ 1,572,900 $ 29,462 $ 1,229,621 $ 49,587 $ 2,802,521 $ 79,049      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 the six months ended June 30, 2018. Proceeds from the sales of securities were approximately $213.9 million with no gain or loss for the six months ended June 30, 2017. Securities with carrying values totaling $ 3.1 billion and $3.3 billion at June 30 , 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	6 Months Ended
	Jun. 30, 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 Louisi ana, the Houston, Texas area, the north ern, central and panhandle regions of Florida , and Nashville, Tennessee . Loans, net of unearned income, by portfolio are presented in the table below.     June 30, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 8,410,961 $ 8,297,937  Commercial real estate - owner occupied 2,233,794 2,142,439  Total commercial and industrial 10,644,755 10,440,376  Commercial real estate - income producing 2,342,192 2,384,599  Construction and land development 1,515,233 1,373,421  Residential mortgages 2,780,359 2,690,472  Consumer 2,088,378 2,115,295  Total loans $ 19,370,917 $ 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 six months ended June 30 , 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 and industrial producing development mortgages Consumer Total  Six Months Ended June 30, 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 (11,845) (6,804) (18,649) (1,604) (220) (498) (12,964) (33,935)  Recoveries 12,476 275 12,751 65 38 712 3,095 16,661  Net provision for loan losses (1,981) 7,727 5,746 1,975 3,121 (862) 11,164 21,144  Reduction as a result of sale of subsidiary — — — — — — (6,648) (6,648)  Ending balance $ 126,568 $ 14,160 $ 140,728 $ 14,145 $ 10,311 $ 24,196 $ 25,150 $ 214,530  Ending balance:  Allowance:  Individually evaluated for impairment $ 19,369 $ 824 $ 20,193 $ 407 $ 1 $ 99 $ 130 $ 20,830  Amounts related to purchased credit impaired loans 427 420 847 46 115 10,873 497 12,378  Collectively evaluated for impairment 106,772 12,916 119,688 13,692 10,195 13,224 24,523 181,322  Total allowance $ 126,568 $ 14,160 $ 140,728 $ 14,145 $ 10,311 $ 24,196 $ 25,150 $ 214,530  Loans:  Individually evaluated for impairment $ 291,071 $ 26,967 $ 318,038 $ 8,820 $ 113 $ 3,733 $ 599 $ 331,303  Purchased credit impaired loans 8,221 6,630 14,851 3,800 4,769 111,805 5,381 140,606  Collectively evaluated for impairment 8,111,669 2,200,197 10,311,866 2,329,572 1,510,351 2,664,821 2,082,398 18,899,008  Total loans $ 8,410,961 $ 2,233,794 $ 10,644,755 $ 2,342,192 $ 1,515,233 $ 2,780,359 $ 2,088,378 $ 19,370,917        Commercial Commercial  Commercial real estate- Total real estate- Construction  non-real owner commercial income and land Residential  (in thousands) estate occupied and industrial producing development mortgages Consumer Total  Six Months Ended June 30, 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 (26,218) (517) (26,735) (160) (172) (776) (15,260) (43,103)  Recoveries 1,818 336 2,154 398 755 281 3,546 7,134  Net provision for loan losses 14,758 1,196 15,954 (207) 195 858 14,142 30,942  Decrease in FDIC loss share receivable (47) — (47) — — (2,344) (135) (2,526)  Ending balance $ 137,363 $ 12,098 $ 149,461 $ 13,540 $ 7,049 $ 23,380 $ 28,435 $ 221,865  Ending balance:  Allowance:  Individually evaluated for impairment $ 22,758 $ 280 $ 23,038 $ 1,402 $ 1 $ 172 $ 283 $ 24,896  Amounts related to purchased credit impaired loans 395 742 1,137 192 239 12,622 942 15,132  Collectively evaluated for impairment 114,210 11,076 125,286 11,946 6,809 10,586 27,210 181,837  Total allowance $ 137,363 $ 12,098 $ 149,461 $ 13,540 $ 7,049 $ 23,380 $ 28,435 $ 221,865  Loans:  Individually evaluated for impairment $ 250,256 $ 7,480 $ 257,736 $ 14,913 $ 847 $ 3,466 $ 1,053 $ 278,015  Purchased credit impaired loans 5,422 9,848 15,270 6,247 4,160 129,198 8,280 163,155  Collectively evaluated for impairment 7,837,426 2,061,004 9,898,430 2,380,513 1,308,515 2,361,259 2,083,954 18,032,671  Total loans $ 8,093,104 $ 2,078,332 $ 10,171,436 $ 2,401,673 $ 1,313,522 $ 2,493,923 $ 2,093,287 $ 18,473,841  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.     June 30, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 155,051 $ 152,863  Commercial real estate - owner occupied 26,216 25,989  Total commercial and industrial 181,267 178,852  Commercial real estate - income producing 10,500 14,574  Construction and land development 4,174 3,807  Residential mortgages 31,393 40,480  Consumer 14,347 15,087  Total loans $ 241,681 $ 252,800 Nonaccrual loans include nonaccruing loans modified in troubled debt restructurings (“TDRs”) of $ 98.8 million and $ 99.2 million at June 30 , 2018 and December 31, 2017, respectively. Total TDRs, both accruing and nonaccruing, were $ 251.3 million at June 30 , 2018 and $ 219.7 million at December 31, 2017. All TDRs are individually evaluated for impairment. At June 30 , 2018 and December 31, 2017, the Company had unfunded commitments of $9.7 million and $7.3 million, respectively, to borrowers whose loan terms have been modified in a TDR. The table s below detail by portfolio class TDRs that were modified during the three and six months ended June 30 , 2018 and 2017:     Three Months Ended  ($ in thousands) June 30, 2018 June 30, 2017  Pre-Modification Post-Modification Pre-Modification Post-Modification  Number Outstanding Outstanding Number Outstanding Outstanding  of Recorded Recorded of Recorded Recorded  Troubled Debt Restructurings: Contracts Investment Investment Contracts Investment Investment  Commercial non-real estate 5 $ 6,477 $ 6,477 28 54,317 54,317  Commercial real estate - owner occupied — — — 3 3,078 3,078  Total commercial and industrial 5 6,477 6,477 31 57,395 57,395  Commercial real estate - income producing — — — 3 959 959  Construction and land development — — — — — —  Residential mortgages 2 75 75 5 848 848  Consumer — — — 1 40 42  Total loans 7 $ 6,552 $ 6,552 40 59,242 59,244      Six Months Ended  ($ in thousands) June 30, 2018 June 30, 2017  Pre-Modification Post-Modification Pre-Modification Post-Modification  Number Outstanding Outstanding Number Outstanding Outstanding  of Recorded Recorded of Recorded Recorded  Troubled Debt Restructurings: Contracts Investment Investment Contracts Investment Investment  Commercial non-real estate 18 $ 61,959 $ 61,959 37 $ 92,976 $ 92,976  Commercial real estate - owner occupied 1 5,909 5,909 4 3,734 3,734  Total commercial and industrial 19 67,868 67,868 41 96,710 96,710  Commercial real estate - income producing 1 1,564 1,564 5 6,486 6,486  Construction and land development — — — — — —  Residential mortgages 3 118 118 6 1,098 1,098  Consumer 1 222 222 1 40 42  Total loans 24 $ 69,772 $ 69,772 53 $ 104,334 $ 104,336   The TDRs modified during the six months ended June 30 , 2018 reflected in the table above include $ 49.6 million of loans with extended amortization terms or other payment concessions, $ 14.6 million with significant covenant waivers and $5 .6 million with other modifications. The TDRs modified during the six months ended June 30 , 2017 include $ 28.4 million of loans with extended amortization terms or other payment concessions, $4 0.2 million with significant covenant waivers and $35 .7 million with other modifications.  One residential mortgage totaling $0.2 million that defaulted during the three and six months ended June 30, 2018 was modified in a TDR during the twelve months prior to default. There were no defaults on loans during the three and six months ended June 30, 2017 that had been modified in a TDR during the prior twelve months. The tables below present loans that are individually evaluated for impairment disaggregated by portfolio class at June 30 , 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.      June 30, 2018  Recorded investment Recorded investment Unpaid  (in thousands) without an allowance with an allowance principal balance Related allowance  Commercial non-real estate $ 125,440 $ 165,631 $ 302,314 $ 19,369  Commercial real estate - owner occupied 8,742 18,225 28,214 824  Total commercial and industrial 134,182 183,856 330,528 20,193  Commercial real estate - income producing 1,765 7,055 9,840 407  Construction and land development 100 13 113 1  Residential mortgages 2,430 1,303 6,748 99  Consumer — 599 599 130  Total loans $ 138,477 $ 192,826 $ 347,828 $ 20,830    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 and 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 and six months ended June 30, 2018 and 2017. Interest income recognized represents interest on accruing loans modified in a TDR.      Three Months Ended  June 30, 2018 June 30, 2017  (in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized  Commercial non-real estate $ 307,492 $ 2,002 $ 241,122 $ 597  Commercial real estate - owner occupied 28,643 102 5,687 18  Total commercial and industrial 336,135 2,104 246,809 615  Commercial real estate - income producing 11,446 24 14,257 34  Construction and land development 113 — 1,219 —  Residential mortgages 6,036 5 3,352 3  Consumer 608 9 1,601 3  Total loans $ 354,338 $ 2,142 $ 267,238 $ 655     Six Months Ended  June 30, 2018 June 30, 2017  (in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized  Commercial non-real estate $ 301,695 $ 3,588 $ 246,374 $ 934  Commercial real estate - owner occupied 27,274 168 5,384 22  Total commercial and industrial 328,969 3,756 251,758 956  Commercial real estate - income producing 13,123 49 14,372 77  Construction and land development 176 — 1,492 —  Residential mortgages 7,762 10 3,572 5  Consumer 781 18 1,876 5  Total loans $ 350,811 $ 3,833 $ 273,070 $ 1,043 Aging Analysis The tables below present the age analysis of past due loans by portfolio class at June 30 , 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  June 30, 2018 past due past due past due past due Current Loans still accruing  (in thousands)  Commercial non-real estate $ 15,299 $ 19,264 $ 94,065 $ 128,628 $ 8,282,333 $ 8,410,961 $ 4,483  Commercial real estate - owner occupied 1,622 1,441 23,274 26,337 2,207,457 2,233,794 2,880  Total commercial and industrial 16,921 20,705 117,339 154,965 10,489,790 10,644,755 7,363  Commercial real estate - income producing 2,133 426 6,666 9,225 2,332,967 2,342,192 1,822  Construction and land development 7,044 723 2,870 10,637 1,504,596 1,515,233 49  Residential mortgages 26,947 10,244 16,549 53,740 2,726,619 2,780,359 118  Consumer 13,566 5,384 7,591 26,541 2,061,837 2,088,378 503  Total $ 66,611 $ 37,482 $ 151,015 $ 255,108 $ 19,115,809 $ 19,370,917 $ 9,855      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 and 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 June 30 , 2018 and December 31, 2017.      June 30, 2018  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial and industrial Commercial real estate - income producing Construction and land development Total commercial  Grade:  Pass $ 7,492,452 $ 2,040,720 $ 9,533,172 $ 2,242,250 $ 1,441,146 $ 13,216,568  Pass-Watch 249,892 43,185 293,077 38,906 56,240 388,223  Special Mention 70,464 26,511 96,975 8,982 7,434 113,391  Substandard 598,136 123,378 721,514 52,054 10,413 783,981  Doubtful 17 — 17 — — 17  Total $ 8,410,961 $ 2,233,794 $ 10,644,755 $ 2,342,192 $ 1,515,233 $ 14,502,180   December 31, 2017  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial and 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       June 30, 2018 December 31, 2017  (in thousands) Residential mortgage Consumer Total Residential mortgage Consumer Total  Performing $ 2,748,848 $ 2,073,528 $ 4,822,376 $ 2,647,784 $ 2,099,637 $ 4,747,421  Nonperforming 31,511 14,850 46,361 42,688 15,658 58,346  Total $ 2,780,359 $ 2,088,378 $ 4,868,737 $ 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 six months ended June 30 , 2018 and the year ended December 31, 2017.      June 30, 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 (21,082) (3,215) (69,591) (7,412)  Accretion 8,285 (8,285) 17,079 (17,079)  Decrease in expected cash flows based on actual cash flows and changes in cash flow assumptions — (1,889) — (30,379)  Net transfers from nonaccretable difference to accretable yield — — — 3,701  Balance at end of period $ 140,606 $ 49,128 $ 153,403 $ 62,517  During the six months ended June 30, 2017, certain of the Company’s purchased credit impaired loans were covered by a loss share agreement with the FDIC. The agreement was terminated by the Company during the third quarter of 2017. Prior to termination of the agreement, t he Company carried a receivable from the FDIC representing an indemnification a sset arising from the agreement . The receivable was accounted for separately from the covered loans as the agreement was not contractually part of the loans and were not transferrable should the Company have disposed of the loans.   Residential Mortgage Loans in Process of Foreclosure  Included in loans are $ 6.2 million and $ 7.5 million of consumer loans secured by single family residential real estate that are in process of foreclosure as of June 30 , 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 $ 2.5 million and $3. 4 million of foreclosed single family residential properties in other real estate owned as of June 30 , 2018 and December 31, 2017, respectively.

Securities Sold under Agreement

Securities Sold under Agreements to Repurchase	6 Months Ended
	Jun. 30, 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 $ 453.0 million and $430.6 million at June 30, 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	6 Months Ended
	Jun. 30, 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 has made 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 June 30, 2018 and December 31, 2017.      June 30, 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 $ — $ 18,321 $ 875,000 $ — $ 14,020  Interest rate swaps Fair Value 483,110 — 4,003 483,110 — 2,475  1,358,110 — 22,324 1,358,110 — 16,495  Derivatives not designated as hedging instruments:  Interest rate swaps (2) N/A 1,227,663 25,797 25,700 1,144,789 15,408 15,857  Risk participation agreements N/A 141,907 8 56 119,951 23 109  Forward commitments to sell residential mortgage loans N/A 106,970 44 950 80,462 1,000 290  Interest rate-lock commitments on residential mortgage loans N/A 69,935 555 16 53,724 186 782  Foreign exchange forward contracts N/A 44,740 1,768 1,732 42,260 2,453 2,419  1,591,215 28,172 28,454 1,441,186 19,070 19,457  Total derivatives $ 2,949,325 $ 28,172 $ 50,778 $ 2,799,296 $ 19,070 $ 35,952  Less: netting adjustment (3) (16,744) (24,825) (4,913) (21,563)  Total derivative assets/liabilities $ 11,428 $ 25,953 $ 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 six months ended June 30, 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 is being amortized over the remaining maturities of the designated instruments. Amortization of other comprehensive loss on terminated cash flow hedges totaled $1.5 million and $2.5 million for the three and six months ended June 30, 2018 , respectively . The notional amounts of the swap agreements in place at June 30 , 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 The Company enters 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 Statement of Income The effects of derivative instruments on the consolidated statements of income are presented in the table below. For the three and six months ended June 30, 2018 , the reduction of interest income attributable to cash flow hedges includes amortization of accumulated other comprehensive loss that resulted from termination of five interest rate swap contracts.     Three Months Ended Six Months Ended  June 30, June 30,  Derivative Instruments: Location of Gain (Loss) Recognized in the Statement of Income: 2018 2017 2018 2017  Interest rate swaps - cash flow hedges Interest income $ (946) $ (210) $ (1,565) $ (96)  Interest rate swaps - fair value hedges Interest expense (519) 303 (646) 444  All other instruments Other noninterest income 1,588 2,680 3,111 3,145  Total $ 123 $ 2,773 $ 900 $ 3,493  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. As of June 30, 2018, the Company was not in violation of any such provisions. 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 June 30, 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 June 30, 2018  Derivative Assets $ 22,669 $ (16,909) $ 5,760 $ 1,118 $ — $ 4,642   Derivative Liabilities $ 24,128 $ (23,010) $ 1,118 $ 1,118 $ 3,033 $ (3,033)      (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	6 Months Ended
	Jun. 30, 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 June 30, 2018 and December 31, 2017 , respectively, with a first-in-first-out cost basi s of $24.1 million and $25.5 m illion at June 30, 2018 and December 31, 2017 , respectively. Shares outstanding also exclude s unvested restricted share awards totaling 1. 5 million at June 30, 2018 and December 31, 2017.  Stock Buyback Program  On May 24, 2018, the Company’s board of directors approved a stock buyback program that authorized the repurchase of up to 5% , or approximately 4.3 million shares, of its outstanding common stock. The approved program allows the Company to repurchase its common shares either in the open market in compliance with Rule 10b-18 promulgated under the Securities Exchange Act of 1934, as amended, or in privately negotiated transactions with non-affiliated sellers or as otherwise determined by the Company in one or more transactions, from time to time until December 31, 2019. The Company is not obligated to purchase any shares under this program, and the board of directors may terminate or amend the program at any time prior to the expiration date. As of June 30, 2018, no shares of the Company’s common stock had been purchased under this program .   A ccumulated Other Comprehensive 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 (loss) 14,687 — — (842) 13,845  Reclassification of net loss realized and included in earnings — — 3,105 — 3,105  Valuation adjustment for pension plan amendment — — 17,315 — 17,315  Other valuation adjustments for employee benefit plan — — (10,782) — (10,782)  Amortization of unrealized net loss on securities transferred to HTM — 1,749 — — 1,749  Income tax expense (benefit) 5,333 657 3,458 (309) 9,139  Balance, June 30, 2017 $ (19,325) $ (13,300) $ (66,321) $ (5,493) $ (104,439)  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 losses (71,759) — — (13,894) (85,653)  Reclassification of net losses realized and included in earnings — — 2,448 1,565 4,013  Other valuation adjustments for employee benefit plan — — (9,039) — (9,039)  Amortization of unrealized net loss on securities transferred to HTM — 1,680 — — 1,680  Income tax expense (benefit) (16,284) 380 (1,494) (2,794) (20,192)  Balance, June 30, 2018 $ (84,987) $ (13,285) $ (84,175) $ (20,762) $ (203,209)  Accumulated Other Comprehensive Income or Loss (“ 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 flo w hedges. Net unrealized gains and 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 or 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 and losses within 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 .      Six Months Ended  Amount reclassified from AOCI (a) June 30, Affected line item on  (in thousands) 2018 2017 the statement of income  Amortization of unrealized net loss on securities transferred to HTM $ (1,680) $ (1,749) Interest income  Tax effect 380 657 Income taxes  Net of tax (1,300) (1,092) Net income  Amortization of defined benefit pension and post-retirement items (2,448) (3,105) Other noninterest expense (b)  Tax effect 555 1,114 Income taxes  Net of tax (1,893) (1,991) Net income  Reclassification of unrealized gain on cash flow hedges 979 — Interest income  Tax effect (222) — Income taxes  Net of tax 757 — Net income  Amortization of loss on terminated cash flow hedges (2,544) — Interest income  Tax effect 577 — Income taxes  Net of tax (1,967) — Net income  Total reclassifications, net of tax $ (4,403) $ (3,083) Net income (a) Amounts in parenthese s 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	6 Months Ended
	Jun. 30, 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 into 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	6 Months Ended
	Jun. 30, 2018
Other Noninterest Income [Abstract]
Other Noninterest Income	9 . Other Noninterest Income Components of other no ninterest income are as follows:       Three Months Ended Six Months Ended  June 30, June 30,  (in thousands) 2018 2017 2018 2017  Income from bank-owned life insurance $ 3,113 $ 2,883 $ 6,183 $ 5,535  Credit related fees 2,416 2,898 5,138 5,776  Income from derivatives 1,588 2,680 3,111 3,145  Gain (loss) on sales of assets 41 (60) (1,166) 4,065  Amortization of FDIC loss share receivable — (1,327) — (2,427)  Other miscellaneous 3,347 4,473 6,724 7,228  Total other noninterest income $ 10,505 $ 11,547 $ 19,990 $ 23,322  

Other Noninterest Expense

Other Noninterest Expense	6 Months Ended
	Jun. 30, 2018
Other Noninterest Expense [Abstract]
Other Noninterest Expense	10 . Other Noninterest Expense Components of other non interest expense are as follows:     Three Months Ended Six Months Ended  June 30, June 30,  (in thousands) 2018 2017 2018 2017  Advertising $ 3,517 $ 4,984 $ 6,043 $ 8,061  Corporate value and franchise taxes 3,577 3,519 7,017 6,555  Printing and supplies 1,688 1,330 2,974 2,508  Travel expense 1,441 1,350 2,507 2,409  Entertainment and contributions 3,193 1,982 5,711 3,765  Tax credit investment amortization 875 1,213 1,749 2,425  FDIC l oss share agreement termination — 6,603 — 6,603  Other retirement expense (4,458) (3,388) (8,921) (6,448)  Loss on restructuring of bank-owned life insurance contracts 3,240 — 3,240 —  Other miscellaneous 8,830 6,686 14,514 13,971  Total other noninterest expense $ 21,903 $ 24,279 $ 34,834 $ 39,849 

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 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 Six Months Ended  June 30, June 30,  (in thousands, except per share data) 2018 2017 2018 2017  Numerator:  Net income to common shareholders $ 71,177 $ 52,267 $ 143,652 $ 101,281  Net income allocated to participating securities - basic and diluted 1,328 1,166 2,694 2,322  Net income allocated to common shareholders - basic and diluted $ 69,849 $ 51,101 $ 140,958 $ 98,959  Denominator:  Weighted-average common shares - basic $ 85,305 $ 84,614 $ 85,273 $ 84,489  Dilutive potential common shares 178 253 178 266  Weighted-average common shares - diluted $ 85,483 $ 84,867 $ 85,451 $ 84,755  Earnings per common share:  Basic $ 0.82 $ 0.60 $ 1.65 $ 1.17  Diluted $ 0.82 $ 0.60 $ 1.65 $ 1.17  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 sh are if the impact would be anti dilutive, i.e., increase earnings per share or redu ce a loss per share. Weighted average anti dilutive potential common shares totaled 1,816 and 913 , respectively, for the three and six months ended June 30, 2018. Weighted average anti dilutive potential common shares totaled 19,397 and 17,701 , respectively, for the three and six months ended June 30, 2017. 

Retirement Plans

Retirement Plans	6 Months Ended
	Jun. 30, 2018
Retirement Plans [Abstract]
Retirement Plans	12. Retirement Plans  The Company sponsors a qualified defined benefit pension plan, the Hancock Whitney Corporation Pension Plan (“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 thereafter 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 is not required to and does not anticipate making a contribution t o the Pension Plan in 2018.  The Company also offers a defined contribution retirement benefit plan (401(k) plan), the Hancock Whitney Corporation 401(k) Savings Plan (“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 provide d 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 June 30, 2018 2018 2017 2018 2017  Service cost $ 3,163 $ 4,093 $ 28 $ 47  Interest cost 4,279 4,291 161 179  Expected return on plan assets (10,169) (9,576) — —  Amortization of net loss and prior service costs 1,365 1,766 (94) (48)  Net periodic benefit cost (reduction of cost) $ (1,362) $ 574 $ 95 $ 178   Other Post-  (in thousands) Pension Benefits Retirement Benefits  Six Months Ended June 30, 2018 2018 2017 2018 2017  Service cost $ 6,088 $ 7,843 $ 63 $ 95  Interest cost 8,202 8,414 298 359  Expected return on plan assets (19,869) (18,326) — —  Amortization of net loss and prior service costs 2,691 3,201 (243) (96)  Net periodic benefit cost (reduction of cost) $ (2,888) $ 1,132 $ 118 $ 358 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	6 Months Ended
	Jun. 30, 2018
Share-Based Payment Arrangements [Abstract]
Share-Based Payment Arrangements	13. Share-Based Payment Arrangements The Company 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 six months ended June 30, 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 (32,458) 37.02 564  Cancelled/Forfeited — — —  Expired (2,298) 44.91 10  Outstanding at June 30, 2018 53,545 $ 33.09 2.8 $ 726  Exercisable at June 30, 2018 53,545 $ 33.09 2.8 $ 726  The total intrinsic value of options exercised for the six months ended June 30, 2018 and 2017 was $ 0.6 million and $4.1 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 June 30, 2018 and changes during the six months ended June 30, 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 82,876 48.81  Vested (28,835) 32.65  Forfeited (49,687) 36.49  Nonvested at June 30, 2018 1,713,296 $ 37.60  As of June 30, 2018, there was $ 43.5 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 3.2 years. The total fair value of shares which vested during the six months ended June 30, 2018 and 2017 was $0. 9 million and $10.0 million, respectively. During the six months ended June 30, 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.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies [Abstract]
Commitments and Contingencies	14. Commitments and Contingencies In the normal course of business, the Bank enters into financial instruments, such as commitments to extend credit and letters of credit, to meet the financing needs of their customers. Such instruments are not reflected in the accompanying consolidated financial statements until they are funded, although they expose the Bank to varying degrees of credit risk and interest rate risk in much the same way as funded loans. Under regulatory capital guidelines, the Company and Bank must include unfunded commitments meeting certain criteria in risk-weighted capital calculation s . Commitments to extend credit include revolving commercial credit lines, nonrevolving loan commitments issued mainly to finance the acquisition and development or construction of real property or equipment, and credit card and personal credit lines. The availability of funds under commercial credit lines and loan commitments generally depends on whether the borrower continues to meet credit standards established in the underlying contract and has not violated other contractual conditions. Loan commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee by the borrower. Credit card and personal credit lines are generally subject to cancellation if the borrower’s credit quality deteriorates. A number of commercial and personal credit lines are used only partially or, in some cases, not at all before they expire, and the total commitment amounts do not necessarily represent future cash requirements of the Company. A substantial majority of the letters of credit are standby agreements that obligate the Bank to fulfill a customer’s financial commitments to a third party if the customer is unable to perform. The Bank issues standby letters of credit primarily to provide credit enhancement to its customers’ other commercial or public financing arrangements and to help them demonstrate financial capacity to vendors of essential goods and services. The contract amounts of these instruments reflect the Company’ s exposure to credit risk. The Company undertakes the same credit evaluation in making loan commitments and assuming conditional obligations as it does for on-balance sheet instruments and may require collateral or other credit support. These off-balance sheet financial instruments are summarized below:     June 30, December 31,  (in thousands) 2018 2017  Commitments to extend credit $ 7,096,587 $ 6,689,033  Letters of credit 362,198 348,377  Legal Proceedings  The Company is party to various legal proceedings arising in the ordinary course of business. Management does not believe that loss contingencies, if any, arising from pending litigation and regulatory matters will have a material adverse effect on the consolidated financial position or liquidity of the Company.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Measurements [Abstract]
Fair Value Measurements	15 . 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.     June 30, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Assets  Available for sale debt securities:  U.S. Treasury and government agency securities $ — $ 90,985 $ — $ 90,985  Municipal obligations — 236,010 — 236,010  Corporate debt securities — 3,500 — 3,500  Residential mortgage-backed securities — 1,774,871 — 1,774,871  Commercial mortgage-backed securities — 729,532 — 729,532  Collateralized mortgage obligations — 146,775 — 146,775  Total available for sale securities — 2,981,673 — 2,981,673  Derivative assets (1) — 11,428 — 11,428  Total recurring fair value measurements - assets $ — $ 2,993,101 $ — $ 2,993,101  Liabilities  Derivative liabilities (1) $ — $ 25,953 $ — $ 25,953  Total recurring fair value measurements - liabilities $ — $ 25,953 $ — $ 25,953      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.      June 30, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Collateral-dependent impaired loans $ — $ 206,110 $ — $ 206,110  Other real estate owned — — 5,926 5,926  Total nonrecurring fair value measurements $ — $ 206,110 $ 5,926 $ 212,036      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 June 30, 2018 and December 31, 2017 .      June 30, 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 $ 459,282 $ — $ — $ 459,282 $ 459,282  Available for sale securities — 2,981,673 — 2,981,673 2,981,673  Held to maturity securities — 3,054,469 — 3,054,469 3,132,200  Loans, net — 206,110 18,633,620 18,839,730 19,156,387  Loans held for sale — 36,047 — 36,047 36,047  Derivative financial instruments — 11,428 — 11,428 11,428   Financial liabilities:  Deposits $ — $ — $ 22,187,823 $ 22,187,823 $ 22,235,338  Federal funds purchased 525 — — 525 525  Securities sold under agreements to repurchase 452,994 — — 452,994 452,994  FHLB short-term borrowings 1,860,671 — — 1,860,671 1,860,671  Long-term debt — 263,134 — 263,134 266,009  Derivative financial instruments — 25,953 — 25,953 25,953      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	6 Months Ended
	Jun. 30, 2018
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncements	1 6 . Recent Accounting Pronouncements  Accounting Standards Adopted in 2018  In March 2018, the FASB issued ASU 2018-05, “Income Taxes (Topic 740): Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118.” The ASU amends Topic 740 to incorporate SEC guidance issued in its Staff Bulletin No. 118 (SAB 118). SAB 118 addressed the application of generally accepted accounting principles in situations when a registrant does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Cuts and Jobs Act. The amendments in this update were effective upon issuance, at which time the Company adopted the standard. Adoption of this standard did not have a material impact on the Company’s financial condition or results of operations.  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 adopted by the Company on January 1, 2018, but did not have a significant impact on the Company’s consolidated financial statements:  · 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 July 2018, the FASB issued ASU 2018-09, “Codification Improvements,” that clarifies certain topics within the Accounting Standards Codification (“ASC”) in an effort to correct unintended application of guidance. The amendments in this Update affect a wide variety of Topics in the Codification, some topics of which are applicable to the Company. The amendments apply to all reporting entities within the scope of the affected accounting guidance. The transition and effective date guidance is based on the facts and circumstances of each amendment, with some of the amendments effective upon issuance of this Update and with other transition guidance effective for annual periods beginning after December 15, 2018 for public business entities. The Company is currently assessing the impact of adoption of this guidance, but does not expect it to have a material impact upon its financial condition or results of operations.  In June 2018, the FASB issued ASU 2018-07, “Compensation – Stock Compensation – (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting,” to expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires good and services to be used or consumed in a grantor’s own operations by issuing share-based payment awards. The amendments also clarify that Topic 718 does not apply to share-based payments used to effectively provide financing to the issuer or awards granted in conjunction with the selling of goods or services to customers as part of a contract accounted for under Topic 606, “Revenue from Contracts with Customers.” The amendments in this Update are effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company does not expect the adoption of this guidance to have a material impact upon its financial condition or results of operations.  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 engaged third party consultant s and formed cross-functional working group s comprised of individuals from various areas including credit, finance, risk management and information technology. Five work streams have been created to develop the expected credit loss models; execute system implementation; complete balance sheet scoping; ensure the design of effective internal controls surrounding new processes; and provide executive oversight of the project. Balance sheet scoping is largely complete. 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),” to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. 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 as 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. Subsequent to the issuance of this Update, the FASB issued three additional ASUs that provide codification improvements and certain transition elections, including ASU 2018-11, which permits an additional transition method whereby an entity may elect to record a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, the 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. Public business entities are required to apply the amendments for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company has preliminarily determined the practical expedients expected to be applied and continues its review of existing service contracts that may include embedded leases. The Company has upgraded its existing third-party leasing software and has begun implementation of the Update , 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 Presentation (Policy)

Basis of Presentation (Policy)	6 Months Ended
	Jun. 30, 2018
Basis of Presentation [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Hancock Whitney Corporation 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. On May 25, 2018, the Company changed its name from Hancock Holding Company to Hancock Whitney Corporation, and its wholly- owned banking subsidiary changed its name from Whitney Bank to Hancock Whitney Bank. In connection with the name change, the Company changed its stock ticker symbol from “HBHC” to “HWC” on the NASDAQ Global Select Market.
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 16 – Recent Accounting Pronouncements for a discussion of accounting standards adopted during the six months ended June 30, 2018.

Securities (Tables)

Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Gain (Loss) on Investments [Line Items]
Amortized Cost and Fair Value of Securities Available for Sale	   Securities Available for Sale  (in thousands) June 30, 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 $ 95,469 — 4,484 90,985 $ 99,535 $ — $ 2,263 $ 97,272  Municipal obligations 244,365 165 8,520 236,010 245,997 1,135 3,346 243,786  Residential mortgage-backed securities 1,826,589 2,609 54,327 1,774,871 1,729,989 5,611 20,387 1,715,213  Commercial mortgage-backed securities 770,769 153 41,390 729,532 704,518 480 17,863 687,135  Collateralized mortgage obligations 150,928 — 4,153 146,775 165,518 4 1,559 163,963  Corporate debt securities 3,500 — — 3,500 3,500 — — 3,500  $ 3,091,620 $ 2,927 $ 112,874 $ 2,981,673 $ 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) June 30, 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 — 668 49,332 $ 50,000 $ — $ 289 $ 49,711  Municipal obligations 704,082 953 14,166 690,869 723,094 8,323 4,245 727,172  Residential mortgage-backed securities 665,846 194 14,730 651,310 725,748 4,175 2,690 727,233  Commercial mortgage-backed securities 357,680 153 14,581 343,252 317,185 40 3,915 313,310  Collateralized mortgage obligations 1,354,592 18 34,904 1,319,706 1,161,484 572 17,472 1,144,584  $ 3,132,200 $ 1,318 $ 79,049 $ 3,054,469 $ 2,977,511 $ 13,110 $ 28,611 $ 2,962,010 
Available for Sale Securities [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 $ 5,073 $ 5,088 Due after one year through five years 57,191 57,118 Due after five years through ten years 1,279,427 1,225,729 Due after ten years 1,749,929 1,693,738 Total available for sale debt securities $ 3,091,620 $ 2,981,673  
Securities with Unrealized Losses	   Available for Sale  June 30, 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 $ 42,423 $ 1,812 $ 48,562 $ 2,672 $ 90,985 $ 4,484  Municipal obligations 54,121 984 168,133 7,536 222,254 8,520  Residential mortgage-backed securities 559,924 8,483 1,066,016 45,844 1,625,940 54,327  Commercial mortgage-backed securities 291,635 10,839 396,809 30,551 688,444 41,390  Collateralized mortgage obligations 115,891 3,007 30,884 1,146 146,775 4,153  $ 1,063,994 $ 25,125 $ 1,710,404 $ 87,749 $ 2,774,398 $ 112,874       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 Securities [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 $ 17,258 $ 17,413 Due after one year through five years 137,093 135,198 Due after five years through ten years 1,474,871 1,436,090 Due after ten years 1,502,978 1,465,768 Total held to maturity securities $ 3,132,200 $ 3,054,469 
Securities with Unrealized Losses	   Held to maturity  June 30, 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 $ — $ — $ 49,332 $ 668 $ 49,332 $ 668  Municipal obligations 364,751 5,081 220,575 9,085 585,326 14,166  Residential mortgage-backed securities 383,695 7,189 211,897 7,541 595,592 14,730  Commercial mortgage-backed securities 232,031 9,079 70,133 5,502 302,164 14,581  Collateralized mortgage obligations 592,423 8,113 677,684 26,791 1,270,107 34,904  $ 1,572,900 $ 29,462 $ 1,229,621 $ 49,587 $ 2,802,521 $ 79,049      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 27

Loans and Allowance for Loan Losses (Tables)	6 Months Ended
	Jun. 30, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, Net of Unearned Income	   June 30, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 8,410,961 $ 8,297,937  Commercial real estate - owner occupied 2,233,794 2,142,439  Total commercial and industrial 10,644,755 10,440,376  Commercial real estate - income producing 2,342,192 2,384,599  Construction and land development 1,515,233 1,373,421  Residential mortgages 2,780,359 2,690,472  Consumer 2,088,378 2,115,295  Total loans $ 19,370,917 $ 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 and industrial producing development mortgages Consumer Total  Six Months Ended June 30, 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 (11,845) (6,804) (18,649) (1,604) (220) (498) (12,964) (33,935)  Recoveries 12,476 275 12,751 65 38 712 3,095 16,661  Net provision for loan losses (1,981) 7,727 5,746 1,975 3,121 (862) 11,164 21,144  Reduction as a result of sale of subsidiary — — — — — — (6,648) (6,648)  Ending balance $ 126,568 $ 14,160 $ 140,728 $ 14,145 $ 10,311 $ 24,196 $ 25,150 $ 214,530  Ending balance:  Allowance:  Individually evaluated for impairment $ 19,369 $ 824 $ 20,193 $ 407 $ 1 $ 99 $ 130 $ 20,830  Amounts related to purchased credit impaired loans 427 420 847 46 115 10,873 497 12,378  Collectively evaluated for impairment 106,772 12,916 119,688 13,692 10,195 13,224 24,523 181,322  Total allowance $ 126,568 $ 14,160 $ 140,728 $ 14,145 $ 10,311 $ 24,196 $ 25,150 $ 214,530  Loans:  Individually evaluated for impairment $ 291,071 $ 26,967 $ 318,038 $ 8,820 $ 113 $ 3,733 $ 599 $ 331,303  Purchased credit impaired loans 8,221 6,630 14,851 3,800 4,769 111,805 5,381 140,606  Collectively evaluated for impairment 8,111,669 2,200,197 10,311,866 2,329,572 1,510,351 2,664,821 2,082,398 18,899,008  Total loans $ 8,410,961 $ 2,233,794 $ 10,644,755 $ 2,342,192 $ 1,515,233 $ 2,780,359 $ 2,088,378 $ 19,370,917        Commercial Commercial  Commercial real estate- Total real estate- Construction  non-real owner commercial income and land Residential  (in thousands) estate occupied and industrial producing development mortgages Consumer Total  Six Months Ended June 30, 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 (26,218) (517) (26,735) (160) (172) (776) (15,260) (43,103)  Recoveries 1,818 336 2,154 398 755 281 3,546 7,134  Net provision for loan losses 14,758 1,196 15,954 (207) 195 858 14,142 30,942  Decrease in FDIC loss share receivable (47) — (47) — — (2,344) (135) (2,526)  Ending balance $ 137,363 $ 12,098 $ 149,461 $ 13,540 $ 7,049 $ 23,380 $ 28,435 $ 221,865  Ending balance:  Allowance:  Individually evaluated for impairment $ 22,758 $ 280 $ 23,038 $ 1,402 $ 1 $ 172 $ 283 $ 24,896  Amounts related to purchased credit impaired loans 395 742 1,137 192 239 12,622 942 15,132  Collectively evaluated for impairment 114,210 11,076 125,286 11,946 6,809 10,586 27,210 181,837  Total allowance $ 137,363 $ 12,098 $ 149,461 $ 13,540 $ 7,049 $ 23,380 $ 28,435 $ 221,865  Loans:  Individually evaluated for impairment $ 250,256 $ 7,480 $ 257,736 $ 14,913 $ 847 $ 3,466 $ 1,053 $ 278,015  Purchased credit impaired loans 5,422 9,848 15,270 6,247 4,160 129,198 8,280 163,155  Collectively evaluated for impairment 7,837,426 2,061,004 9,898,430 2,380,513 1,308,515 2,361,259 2,083,954 18,032,671  Total loans $ 8,093,104 $ 2,078,332 $ 10,171,436 $ 2,401,673 $ 1,313,522 $ 2,493,923 $ 2,093,287 $ 18,473,841  
Composition of Nonaccrual Loans by Portfolio Class	   June 30, December 31,  (in thousands) 2018 2017  Commercial non-real estate $ 155,051 $ 152,863  Commercial real estate - owner occupied 26,216 25,989  Total commercial and industrial 181,267 178,852  Commercial real estate - income producing 10,500 14,574  Construction and land development 4,174 3,807  Residential mortgages 31,393 40,480  Consumer 14,347 15,087  Total loans $ 241,681 $ 252,800 
Troubled Debt Restructurings Modified by Portfolio Class	   Three Months Ended  ($ in thousands) June 30, 2018 June 30, 2017  Pre-Modification Post-Modification Pre-Modification Post-Modification  Number Outstanding Outstanding Number Outstanding Outstanding  of Recorded Recorded of Recorded Recorded  Troubled Debt Restructurings: Contracts Investment Investment Contracts Investment Investment  Commercial non-real estate 5 $ 6,477 $ 6,477 28 54,317 54,317  Commercial real estate - owner occupied — — — 3 3,078 3,078  Total commercial and industrial 5 6,477 6,477 31 57,395 57,395  Commercial real estate - income producing — — — 3 959 959  Construction and land development — — — — — —  Residential mortgages 2 75 75 5 848 848  Consumer — — — 1 40 42  Total loans 7 $ 6,552 $ 6,552 40 59,242 59,244      Six Months Ended  ($ in thousands) June 30, 2018 June 30, 2017  Pre-Modification Post-Modification Pre-Modification Post-Modification  Number Outstanding Outstanding Number Outstanding Outstanding  of Recorded Recorded of Recorded Recorded  Troubled Debt Restructurings: Contracts Investment Investment Contracts Investment Investment  Commercial non-real estate 18 $ 61,959 $ 61,959 37 $ 92,976 $ 92,976  Commercial real estate - owner occupied 1 5,909 5,909 4 3,734 3,734  Total commercial and industrial 19 67,868 67,868 41 96,710 96,710  Commercial real estate - income producing 1 1,564 1,564 5 6,486 6,486  Construction and land development — — — — — —  Residential mortgages 3 118 118 6 1,098 1,098  Consumer 1 222 222 1 40 42  Total loans 24 $ 69,772 $ 69,772 53 $ 104,334 $ 104,336 
Loans Individually Evaluated for Impairment Disaggregated by Portfolio Class	   June 30, 2018  Recorded investment Recorded investment Unpaid  (in thousands) without an allowance with an allowance principal balance Related allowance  Commercial non-real estate $ 125,440 $ 165,631 $ 302,314 $ 19,369  Commercial real estate - owner occupied 8,742 18,225 28,214 824  Total commercial and industrial 134,182 183,856 330,528 20,193  Commercial real estate - income producing 1,765 7,055 9,840 407  Construction and land development 100 13 113 1  Residential mortgages 2,430 1,303 6,748 99  Consumer — 599 599 130  Total loans $ 138,477 $ 192,826 $ 347,828 $ 20,830    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 and 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 and six months ended June 30, 2018 and 2017. Interest income recognized represents interest on accruing loans modified in a TDR.      Three Months Ended  June 30, 2018 June 30, 2017  (in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized  Commercial non-real estate $ 307,492 $ 2,002 $ 241,122 $ 597  Commercial real estate - owner occupied 28,643 102 5,687 18  Total commercial and industrial 336,135 2,104 246,809 615  Commercial real estate - income producing 11,446 24 14,257 34  Construction and land development 113 — 1,219 —  Residential mortgages 6,036 5 3,352 3  Consumer 608 9 1,601 3  Total loans $ 354,338 $ 2,142 $ 267,238 $ 655     Six Months Ended  June 30, 2018 June 30, 2017  (in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized  Commercial non-real estate $ 301,695 $ 3,588 $ 246,374 $ 934  Commercial real estate - owner occupied 27,274 168 5,384 22  Total commercial and industrial 328,969 3,756 251,758 956  Commercial real estate - income producing 13,123 49 14,372 77  Construction and land development 176 — 1,492 —  Residential mortgages 7,762 10 3,572 5  Consumer 781 18 1,876 5  Total loans $ 350,811 $ 3,833 $ 273,070 $ 1,043 
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  June 30, 2018 past due past due past due past due Current Loans still accruing  (in thousands)  Commercial non-real estate $ 15,299 $ 19,264 $ 94,065 $ 128,628 $ 8,282,333 $ 8,410,961 $ 4,483  Commercial real estate - owner occupied 1,622 1,441 23,274 26,337 2,207,457 2,233,794 2,880  Total commercial and industrial 16,921 20,705 117,339 154,965 10,489,790 10,644,755 7,363  Commercial real estate - income producing 2,133 426 6,666 9,225 2,332,967 2,342,192 1,822  Construction and land development 7,044 723 2,870 10,637 1,504,596 1,515,233 49  Residential mortgages 26,947 10,244 16,549 53,740 2,726,619 2,780,359 118  Consumer 13,566 5,384 7,591 26,541 2,061,837 2,088,378 503  Total $ 66,611 $ 37,482 $ 151,015 $ 255,108 $ 19,115,809 $ 19,370,917 $ 9,855      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 and 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	   June 30, 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 (21,082) (3,215) (69,591) (7,412)  Accretion 8,285 (8,285) 17,079 (17,079)  Decrease in expected cash flows based on actual cash flows and changes in cash flow assumptions — (1,889) — (30,379)  Net transfers from nonaccretable difference to accretable yield — — — 3,701  Balance at end of period $ 140,606 $ 49,128 $ 153,403 $ 62,517 
Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Credit Quality Indicators by Segments and Portfolio Class	   June 30, 2018  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial and industrial Commercial real estate - income producing Construction and land development Total commercial  Grade:  Pass $ 7,492,452 $ 2,040,720 $ 9,533,172 $ 2,242,250 $ 1,441,146 $ 13,216,568  Pass-Watch 249,892 43,185 293,077 38,906 56,240 388,223  Special Mention 70,464 26,511 96,975 8,982 7,434 113,391  Substandard 598,136 123,378 721,514 52,054 10,413 783,981  Doubtful 17 — 17 — — 17  Total $ 8,410,961 $ 2,233,794 $ 10,644,755 $ 2,342,192 $ 1,515,233 $ 14,502,180   December 31, 2017  (in thousands) Commercial non-real estate Commercial real estate - owner-occupied Total commercial and 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	   June 30, 2018 December 31, 2017  (in thousands) Residential mortgage Consumer Total Residential mortgage Consumer Total  Performing $ 2,748,848 $ 2,073,528 $ 4,822,376 $ 2,647,784 $ 2,099,637 $ 4,747,421  Nonperforming 31,511 14,850 46,361 42,688 15,658 58,346  Total $ 2,780,359 $ 2,088,378 $ 4,868,737 $ 2,690,472 $ 2,115,295 $ 4,805,767 

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Jun. 30, 2018
Derivatives [Abstract]
Fair Values of Derivative Financial Instruments	     June 30, 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 $ — $ 18,321 $ 875,000 $ — $ 14,020  Interest rate swaps Fair Value 483,110 — 4,003 483,110 — 2,475  1,358,110 — 22,324 1,358,110 — 16,495  Derivatives not designated as hedging instruments:  Interest rate swaps (2) N/A 1,227,663 25,797 25,700 1,144,789 15,408 15,857  Risk participation agreements N/A 141,907 8 56 119,951 23 109  Forward commitments to sell residential mortgage loans N/A 106,970 44 950 80,462 1,000 290  Interest rate-lock commitments on residential mortgage loans N/A 69,935 555 16 53,724 186 782  Foreign exchange forward contracts N/A 44,740 1,768 1,732 42,260 2,453 2,419  1,591,215 28,172 28,454 1,441,186 19,070 19,457  Total derivatives $ 2,949,325 $ 28,172 $ 50,778 $ 2,799,296 $ 19,070 $ 35,952  Less: netting adjustment (3) (16,744) (24,825) (4,913) (21,563)  Total derivative assets/liabilities $ 11,428 $ 25,953 $ 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 June 30, 2018  Derivative Assets $ 22,669 $ (16,909) $ 5,760 $ 1,118 $ — $ 4,642   Derivative Liabilities $ 24,128 $ (23,010) $ 1,118 $ 1,118 $ 3,033 $ (3,033)      (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) 
Effects of Derivative Instruments on the Statement of Income	  Three Months Ended Six Months Ended  June 30, June 30,  Derivative Instruments: Location of Gain (Loss) Recognized in the Statement of Income: 2018 2017 2018 2017  Interest rate swaps - cash flow hedges Interest income $ (946) $ (210) $ (1,565) $ (96)  Interest rate swaps - fair value hedges Interest expense (519) 303 (646) 444  All other instruments Other noninterest income 1,588 2,680 3,111 3,145  Total $ 123 $ 2,773 $ 900 $ 3,493 

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 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 (loss) 14,687 — — (842) 13,845  Reclassification of net loss realized and included in earnings — — 3,105 — 3,105  Valuation adjustment for pension plan amendment — — 17,315 — 17,315  Other valuation adjustments for employee benefit plan — — (10,782) — (10,782)  Amortization of unrealized net loss on securities transferred to HTM — 1,749 — — 1,749  Income tax expense (benefit) 5,333 657 3,458 (309) 9,139  Balance, June 30, 2017 $ (19,325) $ (13,300) $ (66,321) $ (5,493) $ (104,439)  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 losses (71,759) — — (13,894) (85,653)  Reclassification of net losses realized and included in earnings — — 2,448 1,565 4,013  Other valuation adjustments for employee benefit plan — — (9,039) — (9,039)  Amortization of unrealized net loss on securities transferred to HTM — 1,680 — — 1,680  Income tax expense (benefit) (16,284) 380 (1,494) (2,794) (20,192)  Balance, June 30, 2018 $ (84,987) $ (13,285) $ (84,175) $ (20,762) $ (203,209) 
Line Items in Consolidated Income Statements Affected by Amounts Reclassified from Accumulated Other Comprehensive Income	   Six Months Ended  Amount reclassified from AOCI (a) June 30, Affected line item on  (in thousands) 2018 2017 the statement of income  Amortization of unrealized net loss on securities transferred to HTM $ (1,680) $ (1,749) Interest income  Tax effect 380 657 Income taxes  Net of tax (1,300) (1,092) Net income  Amortization of defined benefit pension and post-retirement items (2,448) (3,105) Other noninterest expense (b)  Tax effect 555 1,114 Income taxes  Net of tax (1,893) (1,991) Net income  Reclassification of unrealized gain on cash flow hedges 979 — Interest income  Tax effect (222) — Income taxes  Net of tax 757 — Net income  Amortization of loss on terminated cash flow hedges (2,544) — Interest income  Tax effect 577 — Income taxes  Net of tax (1,967) — Net income  Total reclassifications, net of tax $ (4,403) $ (3,083) Net income (a) Amounts in parenthese s 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)	6 Months Ended
	Jun. 30, 2018
Other Noninterest Income [Abstract]
Components of Other Noninterest Income	   Three Months Ended Six Months Ended  June 30, June 30,  (in thousands) 2018 2017 2018 2017  Income from bank-owned life insurance $ 3,113 $ 2,883 $ 6,183 $ 5,535  Credit related fees 2,416 2,898 5,138 5,776  Income from derivatives 1,588 2,680 3,111 3,145  Gain (loss) on sales of assets 41 (60) (1,166) 4,065  Amortization of FDIC loss share receivable — (1,327) — (2,427)  Other miscellaneous 3,347 4,473 6,724 7,228  Total other noninterest income $ 10,505 $ 11,547 $ 19,990 $ 23,322 

Other Noninterest Expense (Tabl

Other Noninterest Expense (Tables)	6 Months Ended
	Jun. 30, 2018
Other Noninterest Expense [Abstract]
Components of Other Noninterest Expense	   Three Months Ended Six Months Ended  June 30, June 30,  (in thousands) 2018 2017 2018 2017  Advertising $ 3,517 $ 4,984 $ 6,043 $ 8,061  Corporate value and franchise taxes 3,577 3,519 7,017 6,555  Printing and supplies 1,688 1,330 2,974 2,508  Travel expense 1,441 1,350 2,507 2,409  Entertainment and contributions 3,193 1,982 5,711 3,765  Tax credit investment amortization 875 1,213 1,749 2,425  FDIC l oss share agreement termination — 6,603 — 6,603  Other retirement expense (4,458) (3,388) (8,921) (6,448)  Loss on restructuring of bank-owned life insurance contracts 3,240 — 3,240 —  Other miscellaneous 8,830 6,686 14,514 13,971  Total other noninterest expense $ 21,903 $ 24,279 $ 34,834 $ 39,849 

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Computation of Earnings Per Common Share	   Three Months Ended Six Months Ended  June 30, June 30,  (in thousands, except per share data) 2018 2017 2018 2017  Numerator:  Net income to common shareholders $ 71,177 $ 52,267 $ 143,652 $ 101,281  Net income allocated to participating securities - basic and diluted 1,328 1,166 2,694 2,322  Net income allocated to common shareholders - basic and diluted $ 69,849 $ 51,101 $ 140,958 $ 98,959  Denominator:  Weighted-average common shares - basic $ 85,305 $ 84,614 $ 85,273 $ 84,489  Dilutive potential common shares 178 253 178 266  Weighted-average common shares - diluted $ 85,483 $ 84,867 $ 85,451 $ 84,755  Earnings per common share:  Basic $ 0.82 $ 0.60 $ 1.65 $ 1.17  Diluted $ 0.82 $ 0.60 $ 1.65 $ 1.17 

Retirement Plans (Tables)

Retirement Plans (Tables)	6 Months Ended
	Jun. 30, 2018
Retirement Plans [Abstract]
Components of Net Periodic Benefits Cost	   Other Post-  (in thousands) Pension Benefits Retirement Benefits  Three Months Ended June 30, 2018 2018 2017 2018 2017  Service cost $ 3,163 $ 4,093 $ 28 $ 47  Interest cost 4,279 4,291 161 179  Expected return on plan assets (10,169) (9,576) — —  Amortization of net loss and prior service costs 1,365 1,766 (94) (48)  Net periodic benefit cost (reduction of cost) $ (1,362) $ 574 $ 95 $ 178   Other Post-  (in thousands) Pension Benefits Retirement Benefits  Six Months Ended June 30, 2018 2018 2017 2018 2017  Service cost $ 6,088 $ 7,843 $ 63 $ 95  Interest cost 8,202 8,414 298 359  Expected return on plan assets (19,869) (18,326) — —  Amortization of net loss and prior service costs 2,691 3,201 (243) (96)  Net periodic benefit cost (reduction of cost) $ (2,888) $ 1,132 $ 118 $ 358 

Share-Based Payment Arrangeme34

Share-Based Payment Arrangements (Tables)	6 Months Ended
	Jun. 30, 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 (32,458) 37.02 564  Cancelled/Forfeited — — —  Expired (2,298) 44.91 10  Outstanding at June 30, 2018 53,545 $ 33.09 2.8 $ 726  Exercisable at June 30, 2018 53,545 $ 33.09 2.8 $ 726 
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 82,876 48.81  Vested (28,835) 32.65  Forfeited (49,687) 36.49  Nonvested at June 30, 2018 1,713,296 $ 37.60 

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies [Abstract]
Off-Balance Sheet Financial Instruments	  June 30, December 31,  (in thousands) 2018 2017  Commitments to extend credit $ 7,096,587 $ 6,689,033  Letters of credit 362,198 348,377 

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Measurements [Abstract]
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	   June 30, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Assets  Available for sale debt securities:  U.S. Treasury and government agency securities $ — $ 90,985 $ — $ 90,985  Municipal obligations — 236,010 — 236,010  Corporate debt securities — 3,500 — 3,500  Residential mortgage-backed securities — 1,774,871 — 1,774,871  Commercial mortgage-backed securities — 729,532 — 729,532  Collateralized mortgage obligations — 146,775 — 146,775  Total available for sale securities — 2,981,673 — 2,981,673  Derivative assets (1) — 11,428 — 11,428  Total recurring fair value measurements - assets $ — $ 2,993,101 $ — $ 2,993,101  Liabilities  Derivative liabilities (1) $ — $ 25,953 $ — $ 25,953  Total recurring fair value measurements - liabilities $ — $ 25,953 $ — $ 25,953      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	   June 30, 2018  (in thousands) Level 1 Level 2 Level 3 Total  Collateral-dependent impaired loans $ — $ 206,110 $ — $ 206,110  Other real estate owned — — 5,926 5,926  Total nonrecurring fair value measurements $ — $ 206,110 $ 5,926 $ 212,036      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	   June 30, 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 $ 459,282 $ — $ — $ 459,282 $ 459,282  Available for sale securities — 2,981,673 — 2,981,673 2,981,673  Held to maturity securities — 3,054,469 — 3,054,469 3,132,200  Loans, net — 206,110 18,633,620 18,839,730 19,156,387  Loans held for sale — 36,047 — 36,047 36,047  Derivative financial instruments — 11,428 — 11,428 11,428   Financial liabilities:  Deposits $ — $ — $ 22,187,823 $ 22,187,823 $ 22,235,338  Federal funds purchased 525 — — 525 525  Securities sold under agreements to repurchase 452,994 — — 452,994 452,994  FHLB short-term borrowings 1,860,671 — — 1,860,671 1,860,671  Long-term debt — 263,134 — 263,134 266,009  Derivative financial instruments — 25,953 — 25,953 25,953      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 

Basis of Presentation (Narrativ

Basis of Presentation (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Basis of Presentation [Abstract]
Net cash used in investing activities	$ (765,430)	$ (115,567)
Net cash provided by financing activities	513,389	(74,609)
Net cash provided by operating activities	$ 220,165	$ 182,712

Acquisitions and Divestiture (N

Acquisitions and Divestiture (Narrative) (Details) $ in Millions	Mar. 09, 2018USD ($)	Apr. 28, 2017USD ($)	Mar. 10, 2017USD ($)entity	Jul. 13, 2018USD ($)
Harrison Finance Company [Member]
Business Acquisition [Line Items]
Loss from sale of consumer finance subsidiary	$ 1.1
Proceeds from sale of finance subsidiary	$ 78.9
FNBC I [Member] | Whitney Bank [Member]
Business Acquisition [Line Items]
Number of branches | entity			9
Net of cash acquired			$ 323
Cash paid			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
Capital One [Member] | Subsequent Event [Member]
Business Acquisition [Line Items]
Assets under management				$ 4,000
Assets under management and administration				10,400
Cash for customer deposit liabilities assumed				$ 217

Securities (Narrative) (Details

Securities (Narrative) (Details)	6 Months Ended
	Jun. 30, 2018USD ($)item	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Securities [Abstract]
Securities classified as trading	$ 0		$ 0
Proceeds from sales of securities available for sale		$ 213,877,000
Realized gain		0
Realized loss		$ 0
Securities pledged as collateral	$ 3,100,000,000		$ 3,300,000,000
Sale of securities | item	0

Securities (Amortized Cost and

Securities (Amortized Cost and Fair Value of Securities Available for Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	$ 3,091,620	$ 2,949,057
Securities Available for Sale, Gross Unrealized Gains	2,927	7,230
Securities Available for Sale, Gross Unrealized Losses	112,874	45,418
Securities Available for Sale, Fair Value	2,981,673	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	95,469	99,535
Securities Available for Sale, Gross Unrealized Losses	4,484	2,263
Securities Available for Sale, Fair Value	90,985	97,272
Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	244,365	245,997
Securities Available for Sale, Gross Unrealized Gains	165	1,135
Securities Available for Sale, Gross Unrealized Losses	8,520	3,346
Securities Available for Sale, Fair Value	236,010	243,786
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	1,826,589	1,729,989
Securities Available for Sale, Gross Unrealized Gains	2,609	5,611
Securities Available for Sale, Gross Unrealized Losses	54,327	20,387
Securities Available for Sale, Fair Value	1,774,871	1,715,213
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	770,769	704,518
Securities Available for Sale, Gross Unrealized Gains	153	480
Securities Available for Sale, Gross Unrealized Losses	41,390	17,863
Securities Available for Sale, Fair Value	729,532	687,135
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	150,928	165,518
Securities Available for Sale, Gross Unrealized Gains		4
Securities Available for Sale, Gross Unrealized Losses	4,153	1,559
Securities Available for Sale, Fair Value	146,775	163,963
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities Available for Sale, Amortized Cost	3,500	3,500
Securities Available for Sale, Fair Value	$ 3,500	$ 3,500

Securities (Amortized Cost an41

Securities (Amortized Cost and Fair Value of Securities Held to Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	$ 3,132,200	$ 2,977,511
Securities Held to Maturity, Gross Unrealized Gains	1,318	13,110
Securities Held to Maturity, Gross Unrealized Losses	79,049	28,611
Securities Held to Maturity, Fair Value	3,054,469	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	668	289
Securities Held to Maturity, Fair Value	49,332	49,711
Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	704,082	723,094
Securities Held to Maturity, Gross Unrealized Gains	953	8,323
Securities Held to Maturity, Gross Unrealized Losses	14,166	4,245
Securities Held to Maturity, Fair Value	690,869	727,172
Residential Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	665,846	725,748
Securities Held to Maturity, Gross Unrealized Gains	194	4,175
Securities Held to Maturity, Gross Unrealized Losses	14,730	2,690
Securities Held to Maturity, Fair Value	651,310	727,233
Commercial Mortgage-Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	357,680	317,185
Securities Held to Maturity, Gross Unrealized Gains	153	40
Securities Held to Maturity, Gross Unrealized Losses	14,581	3,915
Securities Held to Maturity, Fair Value	343,252	313,310
Collateralized Mortgage Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities Held to Maturity, Amortized Cost	1,354,592	1,161,484
Securities Held to Maturity, Gross Unrealized Gains	18	572
Securities Held to Maturity, Gross Unrealized Losses	34,904	17,472
Securities Held to Maturity, Fair Value	$ 1,319,706	$ 1,144,584

Securities (Amortized Cost an42

Securities (Amortized Cost and Fair Value of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Securities [Abstract]
Debt Securities Available for Sale, Due in one year or less, Amortized Cost	$ 5,073
Debt Securities Available for Sale, Due after one year through five years, Amortized Cost	57,191
Debt Securities Available for Sale, Due after five years through ten years, Amortized Cost	1,279,427
Debt Securities Available for Sale, Due after ten years, Amortized Cost	1,749,929
Total available for sale debt securities, Amortized Cost	3,091,620
Debt Securities Available for Sale, Due in one year or less, Fair Value	5,088
Debt Securities Available for Sale, Due after one year through five years, Fair Value	57,118
Debt Securities Available for Sale, Due after five years through ten years, Fair Value	1,225,729
Debt Securities Available for Sale, Due after ten years, Fair Value	1,693,738
Total available for sale debt securities, Fair Value	2,981,673
Debt Securities Held to Maturity, Due in one year or less, Amortized Cost	17,258
Debt Securities Held to Maturity, Due after one year through five years, Amortized Cost	137,093
Debt Securities Held to Maturity, Due after five years through ten years, Amortized Cost	1,474,871
Debt Securities Held to Maturity, Due after ten years, Amortized Cost	1,502,978
Total held to maturity debt securities, Amortized Cost	3,132,200	$ 2,977,511
Debt Securities Held to Maturity, Due in one year or less, Fair Value	17,413
Debt Securities Held to Maturity, Due after one year through five years, Fair Value	135,198
Debt Securities Held to Maturity, Due after five years through ten years, Fair Value	1,436,090
Debt Securities Held to Maturity, Due after ten years, Fair Value	1,465,768
Total held to maturity debt securities, Fair Value	$ 3,054,469	$ 2,962,010

Securities (Securities Availabl

Securities (Securities Available for Sale with Unrealized Losses) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	$ 1,063,994	$ 842,011
Available for sale, Losses less than 12 months, Gross Unrealized Losses	25,125	6,319
Available for sale, Losses 12 months or longer, Fair Value	1,710,404	1,569,320
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	87,749	39,099
Available for sale, Total, Fair Value	2,774,398	2,411,331
Available for sale, Total, Gross Unrealized Losses	112,874	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	42,423	45,616
Available for sale, Losses less than 12 months, Gross Unrealized Losses	1,812	42
Available for sale, Losses 12 months or longer, Fair Value	48,562	51,157
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	2,672	2,221
Available for sale, Total, Fair Value	90,985	96,773
Available for sale, Total, Gross Unrealized Losses	4,484	2,263
Municipal Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	54,121	2,768
Available for sale, Losses less than 12 months, Gross Unrealized Losses	984	11
Available for sale, Losses 12 months or longer, Fair Value	168,133	173,530
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	7,536	3,335
Available for sale, Total, Fair Value	222,254	176,298
Available for sale, Total, Gross Unrealized Losses	8,520	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	559,924	461,835
Available for sale, Losses less than 12 months, Gross Unrealized Losses	8,483	4,195
Available for sale, Losses 12 months or longer, Fair Value	1,066,016	898,099
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	45,844	16,192
Available for sale, Total, Fair Value	1,625,940	1,359,934
Available for sale, Total, Gross Unrealized Losses	54,327	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	291,635	203,618
Available for sale, Losses less than 12 months, Gross Unrealized Losses	10,839	995
Available for sale, Losses 12 months or longer, Fair Value	396,809	411,046
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	30,551	16,868
Available for sale, Total, Fair Value	688,444	614,664
Available for sale, Total, Gross Unrealized Losses	41,390	17,863
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale, Losses less than 12 months, Fair Value	115,891	128,174
Available for sale, Losses less than 12 months, Gross Unrealized Losses	3,007	1,076
Available for sale, Losses 12 months or longer, Fair Value	30,884	35,488
Available for sale, Losses 12 months or longer, Gross Unrealized Losses	1,146	483
Available for sale, Total, Fair Value	146,775	163,662
Available for sale, Total, Gross Unrealized Losses	$ 4,153	$ 1,559

Securities (Securities Held to

Securities (Securities Held to Maturity with Unrealized Losses) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	$ 1,572,900	$ 768,589
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	29,462	6,515
Held to maturity, Losses 12 months or longer, Fair Value	1,229,621	1,055,983
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	49,587	22,096
Held to maturity, Total, Fair Value	2,802,521	1,824,572
Held to maturity, Total, Gross Unrealized Losses	79,049	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	49,332	49,711
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	668	289
Held to maturity, Total, Fair Value	49,332	49,711
Held to maturity, Total, Gross Unrealized Losses	668	289
Municipal Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	364,751	14,603
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	5,081	19
Held to maturity, Losses 12 months or longer, Fair Value	220,575	230,960
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	9,085	4,226
Held to maturity, Total, Fair Value	585,326	245,563
Held to maturity, Total, Gross Unrealized Losses	14,166	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	383,695	8,815
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	7,189	99
Held to maturity, Losses 12 months or longer, Fair Value	211,897	230,277
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	7,541	2,591
Held to maturity, Total, Fair Value	595,592	239,092
Held to maturity, Total, Gross Unrealized Losses	14,730	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	232,031	174,882
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	9,079	744
Held to maturity, Losses 12 months or longer, Fair Value	70,133	72,499
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	5,502	3,171
Held to maturity, Total, Fair Value	302,164	247,381
Held to maturity, Total, Gross Unrealized Losses	14,581	3,915
Collateralized Mortgage Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held to maturity, Losses less than 12 months, Fair Value	592,423	570,289
Held to maturity, Losses less than 12 months, Gross Unrealized Losses	8,113	5,653
Held to maturity, Losses 12 months or longer, Fair Value	677,684	472,536
Held to maturity, Losses 12 months or longer, Gross Unrealized Losses	26,791	11,819
Held to maturity, Total, Fair Value	1,270,107	1,042,825
Held to maturity, Total, Gross Unrealized Losses	$ 34,904	$ 17,472

Loans and Allowance for Loan 45

Loans and Allowance for Loan Losses (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)loan	Jun. 30, 2017USD ($)loan	Jun. 30, 2018USD ($)loan	Jun. 30, 2017USD ($)loan	Dec. 31, 2017USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 241,681		$ 241,681		$ 252,800
TDRs both accruing and nonaccruing	251,300		251,300		219,700
Post-Modification outstanding recorded investment	6,552	$ 59,244	69,772	$ 104,336
Number of TDRs subsequently defaulted | loan		0		0
Unfunded commitment to borrowers related to modified TDR	9,700		9,700		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	$ 98,800		$ 98,800		99,200
Number of TDRs subsequently defaulted | loan	1		1
Recorded investment	$ 200		$ 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			49,600	$ 28,400
Troubled Debt Restructurings [Member] | Loans With Significant Covenant Waivers [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Convenant waivers			14,600	40,200
Troubled Debt Restructurings [Member] | Loans With Other Modifications [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-Modification outstanding recorded investment			5,600
Other modifications				35,700
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	14,347		14,347		15,087
Post-Modification outstanding recorded investment		$ 42	222	$ 42
Real estate in process of foreclosure	6,200		6,200		7,500
Real estate acquired through foreclosure	$ 2,500		$ 2,500		$ 3,400

Loans and Allowance for Loan 46

Loans and Allowance for Loan Losses (Loans, Net of Unearned Income) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 19,370,917	$ 19,004,163	$ 18,473,841
Residential Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,780,359	2,690,472	2,493,923
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,088,378	2,115,295	2,093,287
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,342,192	2,384,599	2,401,673
Construction and Land Development [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,515,233	1,373,421	1,313,522
Total Commercial And Industrial [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	10,644,755	10,440,376	10,171,436
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	8,410,961	8,297,937	8,093,104
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 2,233,794	$ 2,142,439	$ 2,078,332

Loans and Allowance for Loan 47

Loans and Allowance for Loan Losses (Allowance for Loan Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 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	$ 8,891	$ 14,951	21,144	30,942
Allowance for loan losses: Decrease in FDIC loss share receivable				(2,526)
Reduction as a result of sale of subsidiary			(6,648)
Allowance for loan losses: Ending balance	214,530	221,865	214,530	221,865
Allowance for loan losses: Individually evaluated for impairment	20,830	24,896	20,830	24,896
Allowance for loan losses: Amounts related to purchased credit impaired loans	12,378	15,132	12,378	15,132
Allowance for loan losses: Collectively evaluated for impairment	181,322	181,837	181,322	181,837
Loans: Individually evaluated for impairment	331,303	278,015	331,303	278,015
Loans: Purchased credit impaired loans	140,606	163,155	140,606	163,155
Loans: Collectively evaluated for impairment	18,899,008	18,032,671	18,899,008	18,032,671
Loans receivable	19,370,917	18,473,841	19,370,917	18,473,841	$ 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
Reduction as a result of sale of subsidiary
Allowance for loan losses: Ending balance	14,145	13,540	14,145	13,540
Allowance for loan losses: Individually evaluated for impairment	407	1,402	407	1,402
Allowance for loan losses: Amounts related to purchased credit impaired loans	46	192	46	192
Allowance for loan losses: Collectively evaluated for impairment	13,692	11,946	13,692	11,946
Loans: Individually evaluated for impairment	8,820	14,913	8,820	14,913
Loans: Purchased credit impaired loans	3,800	6,247	3,800	6,247
Loans: Collectively evaluated for impairment	2,329,572	2,380,513	2,329,572	2,380,513
Loans receivable	2,342,192	2,401,673	2,342,192	2,401,673	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
Reduction as a result of sale of subsidiary
Allowance for loan losses: Ending balance	10,311	7,049	10,311	7,049
Allowance for loan losses: Individually evaluated for impairment	1	1	1	1
Allowance for loan losses: Amounts related to purchased credit impaired loans	115	239	115	239
Allowance for loan losses: Collectively evaluated for impairment	10,195	6,809	10,195	6,809
Loans: Individually evaluated for impairment	113	847	113	847
Loans: Purchased credit impaired loans	4,769	4,160	4,769	4,160
Loans: Collectively evaluated for impairment	1,510,351	1,308,515	1,510,351	1,308,515
Loans receivable	1,515,233	1,313,522	1,515,233	1,313,522	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				(2,344)
Reduction as a result of sale of subsidiary
Allowance for loan losses: Ending balance	24,196	23,380	24,196	23,380
Allowance for loan losses: Individually evaluated for impairment	99	172	99	172
Allowance for loan losses: Amounts related to purchased credit impaired loans	10,873	12,622	10,873	12,622
Allowance for loan losses: Collectively evaluated for impairment	13,224	10,586	13,224	10,586
Loans: Individually evaluated for impairment	3,733	3,466	3,733	3,466
Loans: Purchased credit impaired loans	111,805	129,198	111,805	129,198
Loans: Collectively evaluated for impairment	2,664,821	2,361,259	2,664,821	2,361,259
Loans receivable	2,780,359	2,493,923	2,780,359	2,493,923	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				(135)
Reduction as a result of sale of subsidiary			(6,648)
Allowance for loan losses: Ending balance	25,150	28,435	25,150	28,435
Allowance for loan losses: Individually evaluated for impairment	130	283	130	283
Allowance for loan losses: Amounts related to purchased credit impaired loans	497	942	497	942
Allowance for loan losses: Collectively evaluated for impairment	24,523	27,210	24,523	27,210
Loans: Individually evaluated for impairment	599	1,053	599	1,053
Loans: Purchased credit impaired loans	5,381	8,280	5,381	8,280
Loans: Collectively evaluated for impairment	2,082,398	2,083,954	2,082,398	2,083,954
Loans receivable	2,088,378	2,093,287	2,088,378	2,093,287	2,115,295
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(33,935)	(43,103)
Allowance for loan losses: Recoveries			16,661	7,134
Allowance for loan losses: Net provision for loan losses			21,144	30,942
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			(1,604)	(160)
Allowance for loan losses: Recoveries			65	398
Allowance for loan losses: Net provision for loan losses			1,975	(207)
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			(220)	(172)
Allowance for loan losses: Recoveries			38	755
Allowance for loan losses: Net provision for loan losses			3,121	195
Non-Purchased Credit Impaired Loans [Member] | Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(498)	(776)
Allowance for loan losses: Recoveries			712	281
Allowance for loan losses: Net provision for loan losses			(862)	858
Non-Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(12,964)	(15,260)
Allowance for loan losses: Recoveries			3,095	3,546
Allowance for loan losses: Net provision for loan losses			11,164	14,142
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				(47)
Reduction as a result of sale of subsidiary
Allowance for loan losses: Ending balance	140,728	149,461	140,728	149,461
Allowance for loan losses: Individually evaluated for impairment	20,193	23,038	20,193	23,038
Allowance for loan losses: Amounts related to purchased credit impaired loans	847	1,137	847	1,137
Allowance for loan losses: Collectively evaluated for impairment	119,688	125,286	119,688	125,286
Loans: Individually evaluated for impairment	318,038	257,736	318,038	257,736
Loans: Purchased credit impaired loans	14,851	15,270	14,851	15,270
Loans: Collectively evaluated for impairment	10,311,866	9,898,430	10,311,866	9,898,430
Loans receivable	10,644,755	10,171,436	10,644,755	10,171,436	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				(47)
Reduction as a result of sale of subsidiary
Allowance for loan losses: Ending balance	126,568	137,363	126,568	137,363
Allowance for loan losses: Individually evaluated for impairment	19,369	22,758	19,369	22,758
Allowance for loan losses: Amounts related to purchased credit impaired loans	427	395	427	395
Allowance for loan losses: Collectively evaluated for impairment	106,772	114,210	106,772	114,210
Loans: Individually evaluated for impairment	291,071	250,256	291,071	250,256
Loans: Purchased credit impaired loans	8,221	5,422	8,221	5,422
Loans: Collectively evaluated for impairment	8,111,669	7,837,426	8,111,669	7,837,426
Loans receivable	8,410,961	8,093,104	8,410,961	8,093,104	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
Reduction as a result of sale of subsidiary
Allowance for loan losses: Ending balance	14,160	12,098	14,160	12,098
Allowance for loan losses: Individually evaluated for impairment	824	280	824	280
Allowance for loan losses: Amounts related to purchased credit impaired loans	420	742	420	742
Allowance for loan losses: Collectively evaluated for impairment	12,916	11,076	12,916	11,076
Loans: Individually evaluated for impairment	26,967	7,480	26,967	7,480
Loans: Purchased credit impaired loans	6,630	9,848	6,630	9,848
Loans: Collectively evaluated for impairment	2,200,197	2,061,004	2,200,197	2,061,004
Loans receivable	$ 2,233,794	$ 2,078,332	2,233,794	2,078,332	$ 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			(18,649)	(26,735)
Allowance for loan losses: Recoveries			12,751	2,154
Allowance for loan losses: Net provision for loan losses			5,746	15,954
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			(11,845)	(26,218)
Allowance for loan losses: Recoveries			12,476	1,818
Allowance for loan losses: Net provision for loan losses			(1,981)	14,758
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			(6,804)	(517)
Allowance for loan losses: Recoveries			275	336
Allowance for loan losses: Net provision for loan losses			$ 7,727	$ 1,196

Loans and Allowance for Loan 48

Loans and Allowance for Loan Losses (Composition of Nonaccrual Loans by Portfolio Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	$ 241,681	$ 252,800
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	10,500	14,574
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	4,174	3,807
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	31,393	40,480
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	14,347	15,087
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	181,267	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	155,051	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	$ 26,216	$ 25,989

Loans and Allowance for Loan 49

Loans and Allowance for Loan Losses (Troubled Debt Restructurings Modified by Portfolio Class) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)contract	Jun. 30, 2017USD ($)contract	Jun. 30, 2018USD ($)contract	Jun. 30, 2017USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	7	40	24	53
Pre-Modification Outstanding Recorded Investment	$ 6,552	$ 59,242	$ 69,772	$ 104,334
Post-Modification Outstanding Recorded Investment	$ 6,552	$ 59,244	$ 69,772	$ 104,336
Total Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	5	31
Pre-Modification Outstanding Recorded Investment	$ 6,477	$ 57,395
Post-Modification Outstanding Recorded Investment	$ 6,477	$ 57,395
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract		3	1	5
Pre-Modification Outstanding Recorded Investment		$ 959	$ 1,564	$ 6,486
Post-Modification Outstanding Recorded Investment		$ 959	$ 1,564	$ 6,486
Residential Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	2	5	3	6
Pre-Modification Outstanding Recorded Investment	$ 75	$ 848	$ 118	$ 1,098
Post-Modification Outstanding Recorded Investment	$ 75	$ 848	$ 118	$ 1,098
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract		1	1	1
Pre-Modification Outstanding Recorded Investment		$ 40	$ 222	$ 40
Post-Modification Outstanding Recorded Investment		$ 42	$ 222	$ 42
Total Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract			19	41
Pre-Modification Outstanding Recorded Investment			$ 67,868	$ 96,710
Post-Modification Outstanding Recorded Investment			$ 67,868	$ 96,710
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract	5	28	18	37
Pre-Modification Outstanding Recorded Investment	$ 6,477	$ 54,317	$ 61,959	$ 92,976
Post-Modification Outstanding Recorded Investment	$ 6,477	$ 54,317	$ 61,959	$ 92,976
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts | contract		3	1	4
Pre-Modification Outstanding Recorded Investment		$ 3,078	$ 5,909	$ 3,734
Post-Modification Outstanding Recorded Investment		$ 3,078	$ 5,909	$ 3,734

Loans and Allowance for Loan 50

Loans and Allowance for Loan Losses (Loans Individually Evaluated for Impairment Disaggregated by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	$ 138,477		$ 138,477		$ 147,055
Recorded investment with an allowance	192,826		192,826		170,142
Unpaid principal balance	347,828		347,828		341,713
Related allowance	20,830		20,830		18,566
Average recorded investment	354,338	$ 267,238	350,811	$ 273,070
Interest income recognized	2,142	655	3,833	1,043
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	1,765		1,765		5,101
Recorded investment with an allowance	7,055		7,055		10,429
Unpaid principal balance	9,840		9,840		15,687
Related allowance	407		407		1,326
Average recorded investment	11,446	14,257	13,123	14,372
Interest income recognized	24	34	49	77
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	100		100		100
Recorded investment with an allowance	13		13		263
Unpaid principal balance	113		113		363
Related allowance	1		1		11
Average recorded investment	113	1,219	176	1,492
Residential Mortgages [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	2,430		2,430		8,245
Recorded investment with an allowance	1,303		1,303		2,395
Unpaid principal balance	6,748		6,748		13,855
Related allowance	99		99		189
Average recorded investment	6,036	3,352	7,762	3,572
Interest income recognized	5	3	10	5
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment with an allowance	599		599		1,292
Unpaid principal balance	599		599		1,294
Related allowance	130		130		118
Average recorded investment	608	1,601	781	1,876
Interest income recognized	9	3	18	5
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	134,182		134,182		133,609
Recorded investment with an allowance	183,856		183,856		155,763
Unpaid principal balance	330,528		330,528		310,514
Related allowance	20,193		20,193		16,922
Average recorded investment	336,135	246,809	328,969	251,758
Interest income recognized	2,104	615	3,756	956
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	125,440		125,440		116,682
Recorded investment with an allowance	165,631		165,631		151,199
Unpaid principal balance	302,314		302,314		285,685
Related allowance	19,369		19,369		16,129
Average recorded investment	307,492	241,122	301,695	246,374
Interest income recognized	2,002	597	3,588	934
Total Commercial And Industrial [Member] | Total Commercial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded investment without an allowance	8,742		8,742		16,927
Recorded investment with an allowance	18,225		18,225		4,564
Unpaid principal balance	28,214		28,214		24,829
Related allowance	824		824		$ 793
Average recorded investment	28,643	5,687	27,274	5,384
Interest income recognized	$ 102	$ 18	$ 168	$ 22

Loans and Allowance for Loan 51

Loans and Allowance for Loan Losses (Age Analysis of Past Due Loans by Portfolio Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 255,108	$ 327,349
Current	19,115,809	18,676,814
Total loans	19,370,917	19,004,163	$ 18,473,841
Recorded Investment > 90 Days and Accruing	9,855	27,766
30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	66,611	137,267
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	37,482	33,000
Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	151,015	157,082
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	9,225	13,561
Current	2,332,967	2,371,038
Total loans	2,342,192	2,384,599	2,401,673
Recorded Investment > 90 Days and Accruing	1,822	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	2,133	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	426	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	6,666	6,081
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,637	8,581
Current	1,504,596	1,364,840
Total loans	1,515,233	1,373,421	1,313,522
Recorded Investment > 90 Days and Accruing	49	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	7,044	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	723	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	2,870	3,412
Total Commercial [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	154,965	191,167
Current	10,489,790	10,249,209
Total loans	10,644,755	10,440,376	10,171,436
Recorded Investment > 90 Days and Accruing	7,363	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	16,921	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	20,705	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	117,339	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	128,628	166,509
Current	8,282,333	8,131,428
Total loans	8,410,961	8,297,937	8,093,104
Recorded Investment > 90 Days and Accruing	4,483	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	15,299	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	19,264	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	94,065	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	26,337	24,658
Current	2,207,457	2,117,781
Total loans	2,233,794	2,142,439	2,078,332
Recorded Investment > 90 Days and Accruing	2,880	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	1,622	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	1,441	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	23,274	15,517
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	53,740	74,712
Current	2,726,619	2,615,760
Total loans	2,780,359	2,690,472	2,493,923
Recorded Investment > 90 Days and Accruing	118	2,208
Residential Mortgages [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	26,947	33,621
Residential Mortgages [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,244	10,554
Residential Mortgages [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	16,549	30,537
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	26,541	39,328
Current	2,061,837	2,075,967
Total loans	2,088,378	2,115,295	$ 2,093,287
Recorded Investment > 90 Days and Accruing	503	571
Consumer [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	13,566	22,959
Consumer [Member] | 60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,384	7,816
Consumer [Member] | Greater Than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 7,591	$ 8,553

Loans and Allowance for Loan 52

Loans and Allowance for Loan Losses (Credit Quality Indicators by Segments and Portfolio Class) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 14,502,180	$ 14,198,396
Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	13,216,568	12,601,853
Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	388,223	520,230
Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	113,391	126,137
Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	783,981	950,111
Total Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17	65
Residential Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,780,359	2,690,472
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,088,378	2,115,295
Residential Mortgage and Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,868,737	4,805,767
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,342,192	2,384,599
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,242,250	2,223,245
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	38,906	83,444
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,982	13,244
Commercial Real Estate - Income Producing [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	52,054	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	1,515,233	1,373,421
Construction and Land Development [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,441,146	1,291,638
Construction and Land Development [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	56,240	60,804
Construction and Land Development [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,434	4,788
Construction and Land Development [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,413	16,191
Total Commercial And Industrial [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	10,644,755	10,440,376
Total Commercial And Industrial [Member] | Total Commercial [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	9,533,172	9,086,970
Total Commercial And Industrial [Member] | Total Commercial [Member] | Pass-Watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	293,077	375,982
Total Commercial And Industrial [Member] | Total Commercial [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	96,975	108,105
Total Commercial And Industrial [Member] | Total Commercial [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	721,514	869,262
Total Commercial And Industrial [Member] | Total Commercial [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	17	57
Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,410,961	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	7,492,452	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	249,892	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	70,464	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	598,136	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	17	57
Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member] | Total Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,233,794	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	2,040,720	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	43,185	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	26,511	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	123,378	135,704
Performing [Member] | Residential Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,748,848	2,647,784
Performing [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,073,528	2,099,637
Performing [Member] | Residential Mortgage and Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,822,376	4,747,421
Nonperforming [Member] | Residential Mortgages [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	31,511	42,688
Nonperforming [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	14,850	15,658
Nonperforming [Member] | Residential Mortgage and Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 46,361	$ 58,346

Loans and Allowance for Loan 53

Loans and Allowance for Loan Losses (Changes in Carrying Amount of Purchased Credit Impaired Loans and Related Accretable Yield) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 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, Addition of cost recovery loans - FNBC I		15,000
Carrying Amount of Loans, Payments received, net	(21,082)	(69,591)
Carrying Amount of Loans, Accretion	8,285	17,079
Carrying Amount of Loans, Balance at end of period	140,606	153,403
Accretable Yield, Balance at beginning of period	62,517	113,686
Accretable Yield, Payments received, net	(3,215)	(7,412)
Accretable Yield, Accretion	(8,285)	(17,079)
Accretable Yield, Increase (decrease) in expected cash flows based on actual cash flow and changes in cash flow assumptions	(1,889)	(30,379)
Accretable Yield, Net transfers from nonaccretable difference to accretable yield		3,701
Accretable Yield, Balance at end of period	$ 49,128	$ 62,517

Securities Sold under Agreeme54

Securities Sold under Agreements to Repurchase (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Securities Sold under Agreements to Repurchase [Abstract]
Securities sold under agreements to repurchase	$ 453	$ 430.6

Derivatives (Narrative) (Detail

Derivatives (Narrative) (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018USD ($)item	Jun. 30, 2018USD ($)item	Dec. 31, 2017USD ($)
Derivative [Line Items]
Notional amount of derivatives	$ 2,949,325	$ 2,949,325	$ 2,799,296
Derivatives Designated as Hedging Instruments [Member]
Derivative [Line Items]
Notional amount of derivatives	1,358,110	1,358,110	1,358,110
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	875,000
Termination fees		10,600
Amortization of accumulated other comprehensive loss on terminated cash flow hedges	$ 1,500	$ 2,500
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	5
Number of interest rate swap terminated | item		5
Notional amount of derivatives	$ 450,000	$ 450,000
Interest Rate Swaps [Member] | Derivatives Designated as Hedging Instruments [Member] | Cash Flow Hedge [Member] | Date One [Member] | $300 Million Swap Agreement [Member]
Derivative [Line Items]
Notional amount of derivatives	425,000	$ 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] | $200 Million Swap Agreement [Member]
Derivative [Line Items]
Notional amount of derivatives	350,000	$ 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	$ 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	$ 483,110

Derivatives (Fair Values of Der

Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands		6 Months Ended	12 Months Ended
		Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		$ 2,949,325	$ 2,799,296
Fair Values, Assets		5,760	2,148
Fair Values, Liabilities		1,118	3,938
Less: netting adjustment, Assets	[1]	(16,744)	(4,913)
Less: netting adjustment, Liabilities	[1],[2]	(24,825)	(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		1,591,215	1,441,186
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount	[3]	1,227,663	1,144,789
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		141,907	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		106,970	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		69,935	53,724
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Notional or Contractual Amount		44,740	42,260
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		28,172	19,070
Total derivative assets/liabilities		11,428	14,157
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		28,172	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]	25,797	15,408
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		8	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		44	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		555	186
Other Assets [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Assets		1,768	2,453
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2]	50,778	35,952
Total derivative assets/liabilities	[2]	25,953	14,389
Other Liabilities [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2]	22,324	16,495
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2]	28,454	19,457
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2],[3]	25,700	15,857
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2]	56	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	[2]	950	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	[2]	16	782
Other Liabilities [Member] | Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2]	1,732	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 Liabilities [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Values, Liabilities	[2]	18,321	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	[2]	$ 4,003	$ 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]	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	Jun. 30, 2018	Dec. 31, 2017
Derivatives [Abstract]
Gross Amounts Recognized, Derivative Assets	$ 22,669	$ 7,155
Gross Amounts Offset in the Statement of Income, Derivative Assets	(16,909)	(5,007)
Net Amounts Presented in the Statement of Income, Derivative Assets	5,760	2,148
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Assets	1,118	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	4,642
Gross Amounts Recognized, Derivative Liabilities	24,128	24,015
Gross Amounts Offset in the Statement of Income, Derivative Liabilities	(23,010)	(20,077)
Net Amounts Presented in the Statement of Income, Derivative Liabilities	1,118	3,938
Gross Amounts Not Offset in the Statement of Income - Financial Instruments, Derivative Liabilities	1,118	2,148
Gross Amounts Not offset in the Statement of Income - Cash Collateral, Derivative Liabilities	3,033	4,099
Net Amounts Presented in the Statement of Income, Derivative Liabilities	$ (3,033)	$ (2,309)

Derivatives (Effects of Derivat

Derivatives (Effects of Derivative Instruments on the Statement of Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative income reflected in income statement	$ 123	$ 2,773	$ 900	$ 3,493
Interest Rate Swaps [Member] | Interest Income [Member] | Cash Flow Hedge [Member]
Derivative income reflected in income statement	(946)	(210)	(1,565)	(96)
Interest Rate Swaps [Member] | Interest Expense [Member] | Fair Value Hedging [Member]
Derivative income reflected in income statement	(519)	303	(646)	444
All Other Instruments [Member]
Derivative income reflected in income statement	$ 1,588	$ 2,680	$ 3,111	$ 3,145

Stockholders' Equity (Narrative

Stockholders' Equity (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	May 24, 2018	Dec. 31, 2017
Equity, Class of Treasury Stock [Line Items]
Treasury stock shares	1,100,000		1,200,000
Treasury stock, Cost basis	$ 24.1		$ 25.5
Restricted Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares nonvested	1,500,000		1,500,000
2018 Stock Buyback Program [Member]
Equity, Class of Treasury Stock [Line Items]
Shares authorized for repurchase		5.00%
Number of shares authorized for repurchase		4,300,000
Shares repurchased	0

Stockholders' Equity (Component

Stockholders' Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				$ (134,402)	$ (120,532)
Net change in unrealized gain (loss)		$ (23,409)	$ 12,661	(85,653)	13,845
Reclassification of net losses realized and included in earnings		2,217	1,718	4,013	3,105
Valuation adjustment for pension plan amendment			17,315		17,315
Other Valuation adjustment for employee benefit plans		(9,039)	(10,782)	(9,039)	(10,782)
Amortization of unrealized net loss on securities transferred to HTM		925	1,099	1,680	1,749
Income tax expense (benefit)		(6,646)	7,938	(20,192)	9,139
Ending Balance		(203,209)	(104,439)	(203,209)	(104,439)
Accumulcated Other Comprehensive Loss Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				(29,512)	(28,679)
Net change in unrealized gain (loss)				(71,759)	14,687
Income tax expense (benefit)				(16,284)	5,333
Ending Balance		(84,987)	(19,325)	(84,987)	(19,325)
Held to Maturity 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				1,680	1,749
Income tax expense (benefit)				380	657
Ending Balance		(13,285)	(13,300)	(13,285)	(13,300)
Employee Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				(79,078)	(72,501)
Reclassification of net losses realized and included in earnings				2,448	3,105
Valuation adjustment for pension plan amendment					17,315
Other Valuation adjustment for employee benefit plans				(9,039)	(10,782)
Income tax expense (benefit)				(1,494)	3,458
Ending Balance		(84,175)	(66,321)	(84,175)	(66,321)
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance				(11,227)	(4,960)
Net change in unrealized gain (loss)				(13,894)	(842)
Reclassification of net losses realized and included in earnings				1,565
Income tax expense (benefit)				(2,794)	(309)
Ending Balance		$ (20,762)	$ (5,493)	(20,762)	(5,493)
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]			$ (2,448)	$ (3,105)
[1]	Amounts in parentheses 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).

Stockholders' Equity (Line Item

Stockholders' Equity (Line Items in Consolidated Income Statements Affected by Amounts Reclassified from Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension and post-retirement items		$ 17,315		$ 17,315
Employee Benefit Plans [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension and post-retirement items				17,315
Amount Reclassified from Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications, net of tax	[1]		$ (4,403)	(3,083)
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Held to Maturity 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]		(1,680)	(1,749)
Tax effect	[1]		380	657
Net of tax	[1]		(1,300)	(1,092)
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | 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]		(2,448)	(3,105)
Tax effect	[1]		555	1,114
Net of tax	[1]		(1,893)	$ (1,991)
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Gains and Losses on Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification of unrealized gain on cash flow hedges	[1]		979
Tax effect	[1]		(222)
Net of tax	[1]		757
Amortization of loss on terminated cash flash hedges	[1]		(2,544)
Tax effect	[1]		577
Net of tax	[1]		$ (1,967)
[1]	Amounts in parentheses 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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Noninterest Income [Abstract]
Income from bank-owned life insurance	$ 3,113	$ 2,883	$ 6,183	$ 5,535
Credit-related fees	2,416	2,898	5,138	5,776
Income from derivatives	1,588	2,680	3,111	3,145
Gain (loss) on sale of assets	41	(60)	(1,166)	4,065
Amortization of FDIC loss share receivable		(1,327)		(2,427)
Other miscellaneous	3,347	4,473	6,724	7,228
Total other noninterest income	$ 10,505	$ 11,547	$ 19,990	$ 23,322

Other Noninterest Expense (Deta

Other Noninterest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Noninterest Expense [Abstract]
Advertising	$ 3,517	$ 4,984	$ 6,043	$ 8,061
Corporate value and franchise taxes	3,577	3,519	7,017	6,555
Printing and supplies	1,688	1,330	2,974	2,508
Travel expense	1,441	1,350	2,507	2,409
Entertainment and contributions	3,193	1,982	5,711	3,765
Tax credit investment amortization	875	1,213	1,749	2,425
FDIC loss share agreement termination		6,603		6,603
Other retirement expense	(4,458)	(3,388)	(8,921)	(6,448)
Loss on restructuring of bank-owned life insurance contracts	3,240		3,240
Other miscellaneous	8,830	6,686	14,514	13,971
Total other noninterest expense	$ 21,903	$ 24,279	$ 34,834	$ 39,849

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Weighted-average anti-dilutive potential common shares	1,816	19,397	913	17,701

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income to common shareholders	$ 71,177	$ 52,267	$ 143,652	$ 101,281
Net income allocated to participating securities - basic and diluted	1,328	1,166	2,694	2,322
Net income allocated to common shareholders - basic and diluted	$ 69,849	$ 51,101	$ 140,958	$ 98,959
Weighted-average common shares - basic	85,305	84,614	85,273	84,489
Dilutive potential common shares	178	253	178	266
Weighted-average common shares - diluted	85,483	84,867	85,451	84,755
Earnings per common share: Basic	$ 0.82	$ 0.60	$ 1.65	$ 1.17
Earnings per common share: Diluted	$ 0.82	$ 0.60	$ 1.65	$ 1.17

Retirement Plans (Narrative) (D

Retirement Plans (Narrative) (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2018
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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,163	$ 4,093	$ 6,088	$ 7,843
Interest cost	4,279	4,291	8,202	8,414
Expected return on plan assets	(10,169)	(9,576)	(19,869)	(18,326)
Amortization of net loss and prior service costs	1,365	1,766	2,691	3,201
Net periodic benefit cost (reduction of cost)	(1,362)	574	(2,888)	1,132
Other Post-retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	28	47	63	95
Interest cost	161	179	298	359
Amortization of net loss and prior service costs	(94)	(48)	(243)	(96)
Net periodic benefit cost (reduction of cost)	$ 95	$ 178	$ 118	$ 358

Share-Based Payment Arrangeme68

Share-Based Payment Arrangements (Narrative) (Details) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)entity$ / sharesshares	Jun. 30, 2017USD ($)
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised | $	$ 0.6	$ 4.1
Restricted and Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense | $	$ 43.5
Weighted-average period	3 years 2 months 12 days
Total fair value of shares vested | $	$ 0.9	$ 10
Shares granted | shares	82,876
Grant date fair value per share | $ / shares	$ 48.81
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 Arrangeme69

Share-Based Payment Arrangements (Summary of Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 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	(32,458)
Number of Shares, Cancelled/Forfeited
Number of Shares, Expired	(2,298)
Number of Shares, Outstanding at Ending	53,545	88,301
Number of Shares, Exercisable at Ending	53,545
Weighted Average Exercise Price, Outstanding at Beginning	$ 34.84
Weighted Average Exercise Price, Exercised/Released	37.02
Weighted Average Exercise Price, Cancelled/Forfeited
Weighted Average Exercise Price, Expired	44.91
Weighted Average Exercise Price, Outstanding at Ending	33.09	$ 34.84
Weighted Average Exercise Price, Exercisable at Ending	$ 33.09
Weighted Average Remaining Contractual Term (Years)	2 years 9 months 18 days	2 years 9 months 18 days
Weighted Average Remaining Contractual Term (Years), Exercisable at Ending	2 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding at Beginning	$ 1,294
Aggregate Intrinsic Value, Exercised/Released	564
Aggregate Intrinsic Value, Expired	10
Aggregate Intrinsic Value, Outstanding at Ending	726	$ 1,294
Aggregate Intrinsic Value, Exercisable at Ending	$ 726

Share-Based Payment Arrangeme70

Share-Based Payment Arrangements (Summary of Nonvested Restricted and Performance Shares) (Details) - Restricted and Performance Shares [Member]	6 Months Ended
	Jun. 30, 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	82,876
Number of Shares, Vested | shares	(28,835)
Number of Shares, Forfeited | shares	(49,687)
Number of Shares, Nonvested at Ending | shares	1,713,296
Weighted Average Grant Date Fair Value, Nonvested at Beginning | $ / shares	$ 37.05
Weighted Average Grant Date Fair Value, Granted | $ / shares	48.81
Weighted Average Grant Date Fair Value, Vested | $ / shares	32.65
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	36.49
Weighted Average Grant Date Fair Value, Nonvested at Ending | $ / shares	$ 37.60

Commitments and Contingencies71

Commitments and Contingencies (Off-Balance Sheet Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Commitments to extend credit [Member]
Loss Contingencies [Line Items]
Contract amounts	$ 7,096,587	$ 6,689,033
Letters of Credit [Member]
Loss Contingencies [Line Items]
Contract amounts	$ 362,198	$ 348,377

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - Recurring [Member] - USD ($)	6 Months Ended
	Jun. 30, 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		Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		$ 2,981,673	$ 2,910,869
Derivative assets		5,760	2,148
Derivative liabilities		1,118	3,938
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale debt securities		2,981,673	2,910,869
Derivative assets	[1]	11,428	14,157
Total recurring fair value measurements - assets		2,993,101	2,925,026
Derivative liabilities	[1]	25,953	14,389
Total recurring fair value measurements - liabilities		25,953	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		2,981,673	2,910,869
Derivative assets	[1]	11,428	14,157
Total recurring fair value measurements - assets		2,993,101	2,925,026
Derivative liabilities	[1]	25,953	14,389
Total recurring fair value measurements - liabilities		25,953	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		90,985	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		90,985	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		236,010	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		236,010	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		3,500	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		3,500	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		1,774,871	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		1,774,871	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		729,532	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		729,532	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		146,775	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		$ 146,775	$ 163,963
[1]	For further disaggregation of derivative assets and liabilities, see Note 6 - Derivatives.

Fair Value Measurements (Fina74

Fair Value Measurements (Financial Assets Measured at Fair Value on Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	$ 206,110	$ 184,205
Other real estate owned	5,926	6,928
Total nonrecurring fair value measurements	212,036	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	206,110	184,205
Total nonrecurring fair value measurements	206,110	184,205
Nonrecurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate owned	5,926	6,928
Total nonrecurring fair value measurements	$ 5,926	$ 6,928

Fair Value Measurements (Estima

Fair Value Measurements (Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale debt securities	$ 2,981,673	$ 2,910,869
Held to maturity securities	3,132,200	2,977,511
Derivative financial instruments	5,760	2,148
Derivative financial instruments	1,118	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	459,282	479,332
Available for sale debt securities	2,981,673	2,910,869
Held to maturity securities	3,054,469	2,962,010
Loans, net	18,839,730	18,587,508
Loans held for sale	36,047	39,865
Derivative financial instruments	11,428	14,157
Deposits	22,187,823	22,238,847
Federal funds purchased	525	140,754
Securities sold under agreements to repurchase	452,994	430,569
FHLB Short-term borrowings	1,860,671	1,132,567
Long-term debt	263,134	303,631
Derivative financial instruments	25,953	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	459,282	479,332
Federal funds purchased	525	140,754
Securities sold under agreements to repurchase	452,994	430,569
FHLB Short-term borrowings	1,860,671	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	2,981,673	2,910,869
Held to maturity securities	3,054,469	2,962,010
Loans, net	206,110	184,205
Loans held for sale	36,047	39,865
Derivative financial instruments	11,428	14,157
Long-term debt	263,134	303,631
Derivative financial instruments	25,953	14,389
Total Fair Value [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans, net	18,633,620	18,403,303
Deposits	22,187,823	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	459,282	479,332
Available for sale debt securities	2,981,673	2,910,869
Held to maturity securities	3,132,200	2,977,511
Loans, net	19,156,387	18,786,855
Loans held for sale	36,047	39,865
Derivative financial instruments	11,428	14,157
Deposits	22,235,338	22,253,202
Federal funds purchased	525	140,754
Securities sold under agreements to repurchase	452,994	430,569
FHLB Short-term borrowings	1,860,671	1,132,567
Long-term debt	266,009	305,513
Derivative financial instruments	$ 25,953	$ 14,389