Wintrust Financial (WTFC) 10-Q 8 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Entity Current Reporting Status	Yes
Trading Symbol	WTFC
Entity Registrant Name	WINTRUST FINANCIAL CORP
Entity Central Index Key	1,015,328
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		55,923,249

Consolidated Statements Of Cond

Consolidated Statements Of Condition - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Assets
Cash and due from banks	$ 251,896	$ 267,194	$ 242,825
Federal funds sold and securities purchased under resale agreements	56	2,851	4,122
Interest bearing deposits with banks	1,218,728	980,457	816,104
Available-for-sale securities, at fair value	1,665,903	1,724,667	1,650,096
Held-to-maturity securities, at amortized cost ($807.0 million, $607.6 million and $942.7 million fair value at September 30, 2017, December 31, 2016 and September 30, 2016 respectively)	819,340	635,705	932,767
Trading account securities	643	1,989	1,092
Federal Home Loan Bank and Federal Reserve Bank stock	87,192	133,494	129,630
Brokerage customer receivables	23,631	25,181	25,511
Mortgage loans held-for-sale	370,282	418,374	559,634
Loans, net of unearned income, excluding covered loans	20,912,781	19,703,172	19,101,261
Covered loans	46,601	58,145	95,940
Total loans	20,959,382	19,761,317	19,197,201
Allowance for loan losses	(133,119)	(122,291)	(117,693)
Allowance for covered loan losses	(758)	(1,322)	(1,422)
Net loans	20,825,505	19,637,704	19,078,086
Premises and equipment, net	609,978	597,301	597,263
Lease investments, net	193,828	129,402	116,355
Accrued interest receivable and other assets	580,612	593,796	660,923
Trade date securities receivable	189,896	0	677
Goodwill	502,021	498,587	485,938
Other intangible assets	18,651	21,851	20,736
Total assets	27,358,162	25,668,553	25,321,759
Deposits:
Non-interest bearing	6,502,409	5,927,377	5,711,042
Interest bearing	16,392,654	15,731,255	15,436,613
Total deposits	22,895,063	21,658,632	21,147,655
Federal Home Loan Bank advances	468,962	153,831	419,632
Other borrowings	251,680	262,486	241,366
Subordinated notes	139,052	138,971	138,943
Junior subordinated debentures	253,566	253,566	253,566
Trade date securities payable	880	0	0
Accrued interest payable and other liabilities	440,034	505,450	446,123
Total liabilities	24,449,237	22,972,936	22,647,285
Preferred stock, no par value; 20,000,000 shares authorized:
Common stock, no par value; $1.00 stated value; 100,000,000 shares authorized at September 30, 2017, December 31, 2016 and September 30, 2016; 55,939,801 shares issued at September 30, 2017, 51,978,289 shares issued at December 31, 2016 and 51,811,204 shares issued at September 30, 2016	55,940	51,978	51,811
Surplus	1,519,596	1,365,781	1,356,759
Treasury stock, at cost, 101,738 shares at September 30, 2017, 97,749 shares at December 31, 2016, and 96,521 shares at September 30, 2016	(4,884)	(4,589)	(4,522)
Retained earnings	1,254,759	1,096,518	1,051,748
Accumulated other comprehensive loss	(41,486)	(65,328)	(32,579)
Total shareholders’ equity	2,908,925	2,695,617	2,674,474
Total liabilities and shareholders’ equity	27,358,162	25,668,553	25,321,759
Series C - $1,000 liquidation value; no shares issued and outstanding at September 30, 2017, and 126,257 shares issued and outstanding at December 31, 2016 and September 30, 2016, respectively
Preferred stock, no par value; 20,000,000 shares authorized:
Preferred stock, Series C and Series D	0	126,257	126,257
Series D - $25 liquidation value; 5,000,000 shares issued and outstanding at September 30, 2017, December 31, 2016 and September 30, 2016, respectively
Preferred stock, no par value; 20,000,000 shares authorized:
Preferred stock, Series C and Series D	$ 125,000	$ 125,000	$ 125,000

Consolidated Statements Of Con3

Consolidated Statements Of Condition (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Held-to-maturity securities, at Fair value	$ 807,036	$ 607,602	$ 942,666
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000	20,000,000
Common stock, $1.00 stated value (usd per share)	$ 1	$ 1	$ 1
Common stock, 100,000,000 shares authorized (in shares)	100,000,000	100,000,000	100,000,000
Common stock, shares issued (in shares)	55,939,801	51,978,289	51,811,204
Treasury stock, (in shares)	101,738	97,749	96,521
Series C Preferred Stock
Preferred stock, liquidation value per share (usd per share)	$ 1,000	$ 1,000	$ 1,000
Preferred stock, shares outstanding (in shares)	0	126,257	126,257
Series D Preferred Stock
Preferred stock, liquidation value per share (usd per share)	$ 25	$ 25	$ 25
Preferred stock, shares outstanding (in shares)	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	5,000,000	5,000,000	5,000,000

Consolidated Statements Of Inco

Consolidated Statements Of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest income
Interest and fees on loans	$ 227,120	$ 190,189	$ 639,143	$ 541,846
Interest bearing deposits with banks	3,272	1,156	6,529	2,695
Federal funds sold and securities purchased under resale agreements	0	1	2	3
Investment securities	16,058	15,496	45,155	49,084
Trading account securities	8	18	23	43
Federal Home Loan Bank and Federal Reserve Bank stock	1,080	1,094	3,303	3,143
Brokerage customer receivables	150	195	473	630
Total interest income	247,688	208,149	694,628	597,444
Interest expense
Interest on deposits	23,655	15,621	58,396	41,996
Interest on Federal Home Loan Bank advances	2,151	2,577	6,674	8,447
Interest on other borrowings	1,482	1,137	3,770	3,281
Interest on subordinated notes	1,772	1,778	5,330	5,332
Interest on junior subordinated debentures	2,640	2,400	7,481	6,973
Total interest expense	31,700	23,513	81,651	66,029
Net interest income	215,988	184,636	612,977	531,415
Provision for credit losses	7,896	9,571	21,996	26,734
Net interest income after provision for credit losses	208,092	175,065	590,981	504,681
Non-interest income
Wealth management	19,803	19,334	59,856	56,506
Mortgage banking	28,184	34,712	86,061	93,254
Service charges on deposit accounts	8,645	8,024	25,606	23,156
Gains on investment securities, net	39	3,305	31	6,070
Fees from covered call options	1,143	3,633	2,792	9,994
Trading losses, net	(129)	(432)	(869)	(916)
Operating lease income, net	8,461	4,459	21,048	11,270
Other	13,585	13,569	43,943	40,821
Total non-interest income	79,731	86,604	238,468	240,155
Non-interest expense
Salaries and employee benefits	106,251	103,718	312,069	300,423
Equipment	9,947	9,449	28,858	27,523
Operating lease equipment depreciation	6,794	3,605	17,092	9,040
Occupancy, net	13,079	12,767	38,766	36,658
Data processing	7,851	7,432	23,580	21,089
Advertising and marketing	9,572	7,365	23,448	18,085
Professional fees	6,786	5,508	18,956	14,986
Amortization of other intangible assets	1,068	1,085	3,373	3,631
FDIC insurance	3,877	3,686	11,907	11,339
OREO expense, net	590	1,436	2,994	3,344
Other	17,760	20,564	54,194	55,196
Total non-interest expense	183,575	176,615	535,237	501,314
Income before taxes	104,248	85,054	294,212	243,522
Income tax expense	38,622	31,939	105,311	91,255
Net income	65,626	53,115	188,901	152,267
Preferred stock dividends	2,050	3,628	7,728	10,884
Net income applicable to common shares	$ 63,576	$ 49,487	$ 181,173	$ 141,383
Net income per common share-Basic (usd per share)	$ 1.14	$ 0.96	$ 3.34	$ 2.84
Net income per common share-Diluted (usd per share)	1.12	0.92	3.23	2.72
Cash dividends declared per common share (usd per share)	$ 0.14	$ 0.12	$ 0.42	$ 0.36
Weighted average common shares outstanding (in shares)	55,796	51,679	54,292	49,763
Dilutive potential common shares (in shares)	966	4,047	2,305	3,931
Average common shares and dilutive common shares (in shares)	56,762	55,726	56,597	53,694

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 65,626	$ 53,115	$ 188,901	$ 152,267
Unrealized gains on securities
Before tax	811	2,525	25,783	33,669
Tax effect	(158)	(993)	(9,968)	(13,225)
Net of tax	653	1,532	15,815	20,444
Reclassification of net gains included in net income
Before tax	39	3,305	31	6,070
Tax effect	(15)	(1,300)	(12)	(2,386)
Net of tax	24	2,005	19	3,684
Reclassification of amortization of unrealized gains and losses on investment securities transferred to held-to-maturity from available-for-sale
Before tax	33	(3,781)	1,483	(11,038)
Tax effect	(13)	1,486	(583)	4,331
Net of tax	20	(2,295)	900	(6,707)
Net unrealized gains on securities	609	1,822	14,896	23,467
Unrealized gains on derivative instruments
Before tax	394	2,773	1,699	2,728
Tax effect	(158)	(1,090)	(669)	(1,072)
Net unrealized gains on derivative instruments	236	1,683	1,030	1,656
Foreign currency adjustment
Before tax	5,643	(2,237)	10,678	6,966
Tax effect	(1,437)	593	(2,762)	(1,960)
Net foreign currency adjustment	4,206	(1,644)	7,916	5,006
Total other comprehensive income	5,051	1,861	23,842	30,129
Comprehensive income	$ 70,677	$ 54,976	$ 212,743	$ 182,396

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred stock	Common stock	Surplus	Treasury stock	Retained earnings	Accumulated other comprehensive loss
Balance at the beginning at Dec. 31, 2015	$ 2,352,274	$ 251,287	$ 48,469	$ 1,190,988	$ (3,973)	$ 928,211	$ (62,708)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	152,267					152,267
Other comprehensive income, net of tax	30,129						30,129
Cash dividends declared on common stock	(17,846)					(17,846)
Dividends on preferred stock	(10,884)					(10,884)
Stock-based compensation	6,778			6,778
Conversion of Series C preferred stock to common stock	0	(30)	1	29
Common stock issued for:
New issuance, net of costs	152,823		3,000	149,823
Exercise of stock options and warrants	5,773		185	5,965	(377)
Restricted stock awards	37		88	121	(172)
Employee stock purchase plan	1,933		43	1,890
Director compensation plan	1,190		25	1,165
Balance at the end at Sep. 30, 2016	2,674,474	251,257	51,811	1,356,759	(4,522)	1,051,748	(32,579)
Balance at the beginning at Jun. 30, 2016							(34,440)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	53,115
Other comprehensive income, net of tax	1,861
Balance at the end at Sep. 30, 2016	2,674,474	251,257	51,811	1,356,759	(4,522)	1,051,748	(32,579)
Balance at the beginning at Dec. 31, 2016	2,695,617	251,257	51,978	1,365,781	(4,589)	1,096,518	(65,328)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	188,901					188,901
Other comprehensive income, net of tax	23,842						23,842
Cash dividends declared on common stock	(22,932)					(22,932)
Dividends on preferred stock	(7,728)					(7,728)
Stock-based compensation	8,160			8,160
Conversion of Series C preferred stock to common stock	0	(126,257)	3,121	123,136
Common stock issued for:
Exercise of stock options and warrants	20,246		702	19,544
Restricted stock awards	(295)		79	(79)	(295)
Employee stock purchase plan	1,921		28	1,893
Director compensation plan	1,193		32	1,161
Balance at the end at Sep. 30, 2017	2,908,925	125,000	55,940	1,519,596	(4,884)	1,254,759	(41,486)
Balance at the beginning at Jun. 30, 2017							(46,537)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	65,626
Other comprehensive income, net of tax	5,051
Balance at the end at Sep. 30, 2017	$ 2,908,925	$ 125,000	$ 55,940	$ 1,519,596	$ (4,884)	$ 1,254,759	$ (41,486)

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities:
Net income	$ 188,901	$ 152,267
Adjustments to reconcile net income to net cash provided by (used for) operating activities
Provision for credit losses	21,996	26,734
Depreciation, amortization and accretion, net	46,514	38,798
Stock-based compensation expense	8,160	6,778
Net amortization of premium on securities	4,694	3,728
Accretion of discount on loans	(16,885)	(23,416)
Mortgage servicing rights fair value change, net	1,338	(4,810)
Originations and purchases of mortgage loans held-for-sale	(2,812,685)	(3,208,468)
Proceeds from sales of mortgage loans held-for-sale	2,916,368	3,111,318
Bank owned life insurance (BOLI) income	(2,770)	(2,613)
Decrease (increase) in trading securities, net	1,346	(644)
Net decrease in brokerage customer receivables	1,550	2,120
Gains on mortgage loans sold	(67,239)	(74,446)
Gains on investment securities, net	(31)	(6,070)
Gains on early extinguishment of debt	0	(4,305)
Gains on sales of premises and equipment, net	(88)	(89)
Net losses on sales and fair value adjustments of other real estate owned	969	935
Increase in accrued interest receivable and other assets, net	(62,599)	(131,504)
(Decrease) increase in accrued interest payable and other liabilities, net	(81,157)	31,082
Net Cash Provided by (Used for) Operating Activities	148,382	(82,605)
Investing Activities:
Proceeds from maturities of available-for-sale securities	190,799	1,128,428
Proceeds from maturities of held-to-maturity securities	51,282	502
Proceeds from sales and calls of available-for-sale securities	146,518	2,186,662
Proceeds from calls of held-to-maturity securities	51,079	423,866
Purchases of available-for-sale securities	(446,278)	(3,169,020)
Purchases of held-to-maturity securities	(287,976)	(472,803)
Redemption (purchase) of Federal Home Loan Bank and Federal Reserve Bank stock, net	46,302	(28,049)
Net cash paid in business combinations	(284)	(578,315)
Proceeds from sales of other real estate owned	12,892	29,223
Proceeds (paid to) received from the FDIC related to reimbursements on covered assets	(258)	2,124
Net increase in interest bearing deposits with banks	(236,531)	(204,085)
Net increase in loans	(1,176,279)	(1,303,218)
Redemption of BOLI	0	659
Purchases of premises and equipment, net	(39,583)	(28,276)
Net Cash Used for Investing Activities	(1,688,317)	(2,012,302)
Financing Activities:
Increase in deposit accounts	1,236,548	2,408,216
Decrease in subordinated notes and other borrowings, net	(20,111)	(24,545)
Increase (decrease) in Federal Home Loan Bank advances, net	313,000	(440,257)
Proceeds from the issuance of common stock, net	0	152,823
Redemption of junior subordinated debentures, net	0	(10,695)
Issuance of common shares resulting from the exercise of stock options, employee stock purchase plan and conversion of common stock warrants	23,360	9,796
Common stock repurchases for tax withholdings related to stock-based compensation	(295)	(549)
Dividends paid	(30,660)	(28,730)
Net Cash Provided by Financing Activities	1,521,842	2,066,059
Net Increase (Decrease) in Cash and Cash Equivalents	(18,093)	(28,848)
Cash and Cash Equivalents at Beginning of Period	270,045	275,795
Cash and Cash Equivalents at End of Period	$ 251,952	$ 246,947

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements of Wintrust Financial Corporation and Subsidiaries (“Wintrust” or “the Company”) presented herein are unaudited, but in the opinion of management reflect all necessary adjustments of a normal or recurring nature for a fair presentation of results as of the dates and for the periods covered by the consolidated financial statements. The accompanying consolidated financial statements are unaudited and do not include information or footnotes necessary for a complete presentation of financial condition, results of operations or cash flows in accordance with U.S. generally accepted accounting principles ("GAAP"). The unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 (“ 2016 Form 10-K”). Operating results reported for the period are not necessarily indicative of the results which may be expected for the entire year. Reclassifications of certain prior period amounts have been made to conform to the current period presentation. The preparation of the financial statements requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities. Management believes that the estimates made are reasonable, however, changes in estimates may be required if economic or other conditions develop differently from management’s expectations. Certain policies and accounting principles inherently have a greater reliance on the use of estimates, assumptions and judgments and as such have a greater possibility of producing results that could be materially different than originally reported. Management views critical accounting policies to be those which are highly dependent on subjective or complex judgments, estimates and assumptions, and where changes in those estimates and assumptions could have a significant impact on the financial statements. Management currently views the determination of the allowance for loan losses, allowance for covered loan losses and the allowance for losses on lending-related commitments, loans acquired with evidence of credit quality deterioration since origination, estimations of fair value, the valuations required for impairment testing of goodwill, the valuation and accounting for derivative instruments and income taxes as the accounting areas that require the most subjective and complex judgments, and as such could be the most subject to revision as new information becomes available. Descriptions of the Company's significant accounting policies are included in Note 1 - “Summary of Significant Accounting Policies” of the 2016 Form 10-K.

Recent Accounting Developments

Recent Accounting Developments	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Developments	Recent Accounting Developments Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, which created “Revenue from Contracts with Customers (Topic 606),” to clarify the principles for recognizing revenue and develop a common revenue standard for customer contracts. This ASU provides guidance regarding how 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. The ASU also added a new subtopic to the codification, ASC 340-40, “Other Assets and Deferred Costs: Contracts with Customers” to provide guidance on costs related to obtaining and fulfilling a customer contract. Furthermore, the new standard requires disclosure of sufficient information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. At the time ASU No. 2014-09 was issued, the guidance was effective for fiscal years beginning after December 15, 2016. In July 2015, the FASB approved a deferral of the effective date by one year, which would result in the guidance becoming effective for fiscal years beginning after December 15, 2017. The FASB has continued to issue various Updates to clarify and improve specific areas of ASU No. 2014-09. In March 2016, the FASB issued ASU No. 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” to clarify the implementation guidance within ASU No. 2014-09 surrounding principal versus agent considerations and its impact on revenue recognition. In April 2016, the FASB issued ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” to also clarify the implementation guidance within ASU No. 2014-09 related to these two topics. In May 2016, the FASB issued ASU No. 2016-11, “Revenue Recognition (Topic 605) and Derivative and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting,” to remove certain areas of SEC Staff Guidance from those specific Topics. In May 2016 and December 2016, the FASB issued ASU 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients” and ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers,” to clarify specific aspects of implementation, including the collectability criterion, exclusion of sales taxes collected from a transaction price, noncash consideration, contract modifications, completed contracts at transition, the applicability of loan guarantee fees, impairment of capitalized contract costs and certain disclosure requirements. In February 2017, the FASB issued ASU No. 2017-05, “Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets,” to clarify the implementation guidance within ASU No. 2014-09 surrounding transfers of nonfinancial assets, including partial sales of such assets, and its impact on revenue recognition. Like ASU No. 2014-09, this guidance is effective for fiscal years beginning after December 15, 2017. The Company continues to evaluate the impact on the consolidated financial statements of adopting this new guidance. As certain significant revenue sources related to financial instruments such as interest income are considered not in-scope, the Company does not believe the new guidance will have a significant impact on its consolidated financial statements. The Company is currently completing reviews of specific contracts with customers across its various sources of revenue, primarily related to revenue from its wealth management segment. Contract reviews assist in identifying any characteristics of such contracts that could result in a change in the Company's current practices for recognition of revenue and recognition of costs incurred to obtain or fulfill such contracts. Additionally, during these contract reviews, the Company is considering any disclosure impact that may arise from characteristics identified. The Company expects to adopt the new guidance using the modified retrospective approach. Financial Instruments In January 2016, the FASB issued ASU No. 2016-01, “ Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ” to improve the accounting for financial instruments. This ASU requires equity investments with readily determinable fair values to be measured at fair value with changes recognized in net income regardless of classification. For equity investments without a readily determinable fair value, the value of the investment would be measured at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer instead of fair value, unless a qualitative assessment indicates impairment. Additionally, this ASU requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. This guidance is effective for fiscal years beginning after December 15, 2017 and is to be applied prospectively with a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Leases In February 2016, the FASB issued ASU No. 2016-02, “ Leases (Topic 842), ” to improve transparency and comparability across entities regarding leasing arrangements. This ASU requires the recognition of a separate lease liability representing the required discounted lease payments over the lease term and a separate lease asset representing the right to use the underlying asset during the same lease term. Additionally, this ASU provides clarification regarding the identification of certain components of contracts that would represent a lease as well as requires additional disclosures to the notes of the financial statements. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach, including the option to apply certain practical expedients. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements. Excluding any impact from the clarification of contracts representing a lease, the Company expects to recognize separate lease liabilities and right to use assets for the amounts related to certain facilities under operating lease agreements disclosed in Note 15 - Minimum Lease Commitments in the 2016 Form 10-K . Additionally, the Company does not expect to significantly change operating lease agreements prior to adoption. Derivatives In March 2016, the FASB issued ASU No. 2016-05, “ Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships, ” to clarify guidance surrounding the effect on an existing hedging relationship of a change in the counterparty to a derivative instrument that has been designated as a hedging instrument. This ASU states that a change in counterparty to such derivative instrument does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. This guidance was effective for fiscal years beginning after December 15, 2016 and did not have a material impact on the Company's consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, “ Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, ” to improve the financial reporting of hedging relationships to better align the economic results of an entity’s risk management activities and disclosures within its financial statements. In addition, this ASU makes certain targeted improvements to simplify the application of the hedge accounting to derivative instruments. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Guidance related to existing cash flow hedges is to be applied under a modified retrospective approach and guidance related to amended presentation and disclosures is to be applied under a prospective approach. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements. Equity Method Investments In March 2016, the FASB issued ASU No. 2016-07, “ Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting, ” to simplify the accounting for investments qualifying for the use of the equity method of accounting. This ASU eliminates the requirement to retroactively adopt the equity method of accounting when an investment qualifies for such method as a result of an increase in the level of ownership interest or degree of influence. The ASU requires the equity method investor add the cost of acquiring the additional interest to the current basis and adopt the equity method of accounting as of that date going forward. Additionally, for available-for-sale equity securities that become qualified for equity method accounting, the ASU requires the related unrealized holding gains or losses included in accumulated other comprehensive income be recognized in earnings at the date the investment qualifies for such accounting. This guidance was effective for fiscal years beginning after December 15, 2016 and did not have a material impact on the Company's consolidated financial statements. Employee Share-Based Compensation In March 2016, the FASB issued ASU No. 2016-09, “ Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, ” to simplify the accounting for several areas of share-based payment transactions. This included the recognition of all excess tax benefits and tax deficiencies as income tax expense instead of surplus, the classification on the statement of cash flows of excess tax benefits and taxes paid when the employer withholds shares for tax-withholding purposes. Additionally, related to forfeitures, the ASU provides the option to estimate the number of awards that are expected to vest or account for forfeitures as they occur. This guidance was effective for fiscal years beginning after December 15, 2016. In the first nine months of 2017, the Company recorded $5.0 million of excess tax benefits within income tax expense on the Consolidated Statements of Income as a result of adoption. Allowance for Credit Losses In June 2016, the FASB issued ASU No. 2016-13, “ Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, ” to replace the current incurred loss methodology for recognizing credit losses, which delays recognition until it is probable a loss has been incurred, with a methodology that reflects an estimate of all expected credit losses and considers additional reasonable and supportable forecasted information when determining credit loss estimates. This impacts the calculation of the allowance for credit losses for all financial assets measured under the amortized cost basis, including PCI loans at the time of and subsequent to acquisition. Additionally, credit losses related to available-for-sale debt securities would be recorded through the allowance for credit losses and not as a direct adjustment to the amortized cost of the securities. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements as well as the impact on current systems and processes. Specifically, the Company has established a group consisting of individuals from the various areas of the Company tasked with transitioning to the new requirements. At this time, the Company is reviewing potential methodologies for estimating expected credit losses using reasonable and supportable forecast information and has identified certain historical data and system requirements. Statement of Cash Flows In August 2016, the FASB issued ASU No. 2016-15, “ Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the FASB Emerging Issues Task Force), ” to clarify the presentation of specific types of cash flow receipts and payments, including the payment of debt prepayment or debt extinguishment costs, contingent consideration cash payments paid subsequent to the acquisition date and proceeds from settlement of BOLI policies . This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a retrospective approach, if practicable. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18 “ Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force), ” to clarify the classification and presentation of changes in restricted cash on the statement of cash flows . This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a retrospective approach. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Income Taxes In October 2016, the FASB issued ASU No. 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory,” to improve the accounting for intra-entity transfers of assets other than inventory. This ASU allows the recognition of current and deferred income taxes for such transfers prior to the subsequent sale of the transferred assets to an outside party. Initial recognition of current and deferred income taxes is currently prohibited for intra-entity transfers of assets other than inventory. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach through cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Consolidation In October 2016, the FASB issued ASU No. 2016-17, “ Consolidation (Topic 810): Interest Held through Related Parties That Are under Common Control, ” to amend guidance from ASU No. 2015-02 regarding how a reporting entity treats indirect interests in a variable interest entity (“VIE”) held through related parties under common control when determining whether the reporting entity is the primary beneficiary of such VIE . This guidance was effective for fiscal years beginning after December 15, 2016 and did not have a material impact on the Company's consolidated financial statements. Business Combinations In January 2017, the FASB issued ASU No. 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business,” to improve such definition and, as a result, assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or as business combinations. The definition of a business impacts many areas of accounting including acquisitions, disposals, goodwill and consolidation. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a prospective approach. The Company expects the adoption of this new guidance to impact the determination of whether future acquisitions are considered a business combination and the resulting impact of such determination on the consolidated financial statements. Goodwill In January 2017, the FASB issued ASU No. 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” to simplify the subsequent measurement of goodwill. When the carrying amount of a reporting unit exceeds its fair value, an entity would no longer be required to determine goodwill impairment by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit was acquired in a business combination. Goodwill impairment would be recognized according to the excess of the carrying amount of the reporting unit over the calculated fair value of such unit. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and is to be applied under a prospective approach. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Compensation In March 2017, the FASB issued ASU No. 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. An entity will be required to report the service cost component of such costs in the same line item or items as other compensation costs related to services rendered. Additionally, only the service cost component will be eligible for capitalization when applicable. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a retrospective approach related to presentation of the service cost component and a prospective approach related to capitalization of such costs. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. When adopted, the Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting,” to clarify when modification accounting is appropriate for changes to the terms and conditions of a share-based payment award. An entity will be required to account for such changes as a modification unless certain criteria is met. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a prospective approach for awards modified on or after the adoption date. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. When adopted, the Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Amortization of Premium on Certain Debt Securities In March 2017, the FASB issued ASU No. 2017-08, “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities,” to amend the amortization period for certain purchased callable debt securities held at a premium. The amortization period for such securities will be shortened to the earliest call date. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements.

Business Combinations

Business Combinations	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Business Combinations	Business Combinations Non-FDIC Assisted Bank Acquisitions On November 18, 2016 , the Company acquired First Community Financial Corporation ("FCFC"). FCFC was the parent company of First Community Bank. Through this transaction, the Company acquired First Community Bank's two banking locations in Elgin, Illinois . First Community Bank was merged into the Company's wholly-owned subsidiary St. Charles Bank & Trust Company ("St. Charles Bank"). The Company acquired assets with a fair value of approximately $187.2 million , including approximately $79.5 million of loans, and assumed deposits with a fair value of approximately $150.3 million . Additionally, the Company recorded goodwill of $ 13.8 million on the acquisition. On August 19, 2016 , the Company, through its wholly-owned subsidiary Lake Forest Bank & Trust Company ("Lake Forest Bank"), acquired approximately $561.4 million in performing loans and related relationships from an affiliate of GE Capital Franchise Finance. The loans are to franchise operators (primarily quick service restaurant concepts) in the Midwest and in the Western portion of the United States. On March 31, 2016 , the Company acquired Generations Bancorp, Inc. ("Generations"). Generations was the parent company of Foundations Bank, which had one banking location in Pewaukee, Wisconsin. Foundations Bank was merged into the Company's wholly-owned subsidiary Town Bank. The Company acquired assets with a fair value of approximately $134.2 million , including approximately $67.4 million of loans, and assumed deposits with a fair value of approximately $100.2 million . Additionally, the Company recorded goodwill of $11.5 million on the acquisition. FDIC-Assisted Transactions From 2010 to 2012, the Company acquired the banking operations, including the acquisition of certain assets and the assumption of liabilities, of nine financial institutions in FDIC-assisted transactions. Loans comprise the majority of the assets acquired in nearly all of these FDIC-assisted transactions, of which eight such transactions are subject to loss sharing agreements with the FDIC whereby the FDIC has agreed to reimburse the Company for 80% of losses incurred on the purchased loans, other real estate owned (“OREO”), and certain other assets. Additionally, clawback provisions within these loss share agreements with the FDIC require the Company to reimburse the FDIC in the event that actual losses on covered assets are lower than the original loss estimates agreed upon with the FDIC with respect of such assets in the loss share agreements. The Company refers to the loans subject to these loss sharing agreements as “covered loans” and uses the term “covered assets” to refer to covered loans, covered OREO and certain other covered assets during periods subject to such agreements. The agreements with the FDIC require that the Company follow certain servicing procedures or risk losing the FDIC reimbursement of covered asset losses. As of dates subject to such agreements, the loans covered by loss share agreements are classified and presented as covered loans and the estimated reimbursable losses are recorded as an FDIC indemnification asset or other liability in the Consolidated Statements of Condition. The Company recorded the acquired assets and liabilities at their estimated fair values at the acquisition date. The fair value for loans reflected expected credit losses at the acquisition date. Therefore, the Company will only recognize a provision for credit losses and charge-offs on the acquired loans for any further credit deterioration subsequent to the acquisition date. See Note 7 — Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans for further discussion of the allowance on covered loans. The loss share agreements with the FDIC cover realized losses on loans, foreclosed real estate and certain other assets and require the Company to record loss share assets and liabilities that are measured separately from the loan portfolios because they are not contractually embedded in the loans and are not transferable with the loans should the Company choose to dispose of them. Fair values at the acquisition dates were estimated based on projected cash flows available for loss share based on the credit adjustments estimated for each loan pool and the loss share percentages. The loss share assets and liabilities are recorded as FDIC indemnification assets and other liabilities, respectively, on the Consolidated Statements of Condition as of dates covered by loss share agreements. Subsequent to the acquisition date, reimbursements received from the FDIC for actual incurred losses will reduce the FDIC indemnification assets. Reductions to expected losses, to the extent such reductions to expected losses are the result of an improvement to the actual or expected cash flows from the covered assets, will also reduce the FDIC indemnification assets and, if necessary, increase any loss share liability when necessary reductions exceed the current value of the FDIC indemnification assets. In accordance with the clawback provision noted above, the Company may be required to reimburse the FDIC when actual losses are less than certain thresholds established for each loss share agreement. The balance of these estimated reimbursements in accordance with clawback provisions and any related amortization are adjusted periodically for changes in the expected losses on covered assets. On the Consolidated Statements of Condition as of dates subject to loss share agreements, estimated reimbursements from clawback provisions are recorded as a reduction to the FDIC indemnification asset or, if necessary, an increase to the loss share liability, which is included within accrued interest payable and other liabilities. In the second quarter of 2017, the Company recorded a $4.9 million reduction to the estimated loss share liability as a result of an adjustment related to such clawback provisions. Although these assets are contractual receivables from the FDIC and these liabilities are contractual payables to the FDIC, there are no contractual interest rates. Additional expected losses, to the extent such expected losses result in recognition of an allowance for covered loan losses, will increase the FDIC indemnification asset or reduce the FDIC indemnification liability. The corresponding amortization is recorded as a component of non-interest income on the Consolidated Statements of Income during periods covered by loss share agreements. The following table summarizes the activity in the Company’s FDIC indemnification liability during the periods indicated: Three Months Ended Nine Months Ended (Dollars in thousands) September 30, September 30, September 30, September 30, Balance at beginning of period $ 15,375 $ 11,729 $ 16,701 $ 6,100 Reductions from reimbursable expenses (159 ) (21 ) (316 ) (751 ) Amortization 311 456 1,010 1,322 Changes in expected reimbursements from (to) the FDIC for changes in expected credit losses and reimbursable expenses 994 4,077 (1,665 ) 9,150 Payments (paid to) received from the FDIC (1,049 ) 1,704 (258 ) 2,124 Balance at end of period $ 15,472 $ 17,945 $ 15,472 $ 17,945 On October 16, 2017, the Company entered into agreements with the FDIC that terminate all existing loss share agreements with the FDIC. See Note 17 - Subsequent Events for further discussion of the termination of FDIC loss share agreements. Mortgage Banking Acquisitions On February 14, 2017, the Company acquired certain assets and assumed certain liabilities of the mortgage banking business of American Homestead Mortgage, LLC ("AHM"). The Company recorded goodwill of $999,000 on the acquisition. PCI Loans Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date. Expected future cash flows at the purchase date in excess of the fair value of loans are recorded as interest income over the life of the loans if the timing and amount of the future cash flows is reasonably estimable (“accretable yield”). The difference between contractually required payments and the cash flows expected to be collected at acquisition is referred to as the non-accretable difference and represents probable losses in the portfolio. In determining the acquisition date fair value of PCI loans, and in subsequent accounting, the Company aggregates these purchased loans into pools of loans by common risk characteristics, such as credit risk rating and loan type. Subsequent to the purchase date, increases in cash flows over those expected at the purchase date are recognized as interest income prospectively. Subsequent decreases to the expected cash flows will generally result in a provision for loan losses. The Company purchased a portfolio of life insurance premium finance receivables in 2009. These purchased life insurance premium finance receivables are valued on an individual basis. If credit related conditions deteriorate, an allowance related to these loans will be established as part of the provision for credit losses. See Note 6—Loans, for additional information on PCI loans.

Cash and Cash Equivalents

Cash and Cash Equivalents	9 Months Ended
	Sep. 30, 2017
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of the Consolidated Statements of Cash Flows, the Company considers cash and cash equivalents to include cash on hand, cash items in the process of collection, non-interest bearing amounts due from correspondent banks, federal funds sold and securities purchased under resale agreements with original maturities of three months or less.

Investment Securities

Investment Securities	9 Months Ended
	Sep. 30, 2017
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Investment Securities	Investment Securities The following tables are a summary of the available-for-sale and held-to-maturity securities portfolios as of the dates shown: September 30, 2017 (Dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities U.S. Treasury $ 144,872 $ — $ (727 ) $ 144,145 U.S. Government agencies 159,884 10 (566 ) 159,328 Municipal 113,796 2,493 (273 ) 116,016 Corporate notes: Financial issuers 60,325 63 (771 ) 59,617 Other 1,000 — (3 ) 997 Mortgage-backed: (1) Mortgage-backed securities 1,114,655 1,477 (30,436 ) 1,085,696 Collateralized mortgage obligations 63,934 230 (412 ) 63,752 Equity securities 33,166 3,867 (681 ) 36,352 Total available-for-sale securities $ 1,691,632 $ 8,140 $ (33,869 ) $ 1,665,903 Held-to-maturity securities U.S. Government agencies $ 585,061 $ 249 $ (12,579 ) $ 572,731 Municipal 234,279 2,185 (2,159 ) 234,305 Total held-to-maturity securities $ 819,340 $ 2,434 $ (14,738 ) $ 807,036 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available-for-sale securities U.S. Treasury $ 142,741 $ 1 $ (759 ) $ 141,983 U.S. Government agencies 189,540 47 (435 ) 189,152 Municipal 129,446 2,969 (606 ) 131,809 Corporate notes: Financial issuers 65,260 132 (1,000 ) 64,392 Other 1,000 — (1 ) 999 Mortgage-backed: (1) Mortgage-backed securities 1,185,448 284 (54,330 ) 1,131,402 Collateralized mortgage obligations 30,105 67 (490 ) 29,682 Equity securities 32,608 3,429 (789 ) 35,248 Total available-for-sale securities $ 1,776,148 $ 6,929 $ (58,410 ) $ 1,724,667 Held-to-maturity securities U.S. Government agencies $ 433,343 $ 7 $ (24,470 ) $ 408,880 Municipal 202,362 647 (4,287 ) 198,722 Total held-to-maturity securities $ 635,705 $ 654 $ (28,757 ) $ 607,602 September 30, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available-for-sale securities U.S. Treasury $ 30,017 $ 19 $ — $ 30,036 U.S. Government agencies 93,561 163 (41 ) 93,683 Municipal 106,033 3,395 (147 ) 109,281 Corporate notes: Financial issuers 65,215 299 (1,311 ) 64,203 Other 1,000 — — 1,000 Mortgage-backed: (1) Mortgage-backed securities 1,257,070 7,958 (54 ) 1,264,974 Collateralized mortgage obligations 35,935 304 (102 ) 36,137 Equity securities 48,568 2,998 (784 ) 50,782 Total available-for-sale securities $ 1,637,399 $ 15,136 $ (2,439 ) $ 1,650,096 Held-to-maturity securities U.S. Government agencies $ 729,417 $ 7,577 $ (2,879 ) $ 734,115 Municipal 203,350 5,515 (314 ) 208,551 Total held-to-maturity securities $ 932,767 $ 13,092 $ (3,193 ) $ 942,666 (1) Consisting entirely of residential mortgage-backed securities, none of which are subprime. The following table presents the portion of the Company’s available-for-sale and held-to-maturity securities portfolios which has gross unrealized losses, reflecting the length of time that individual securities have been in a continuous unrealized loss position at September 30, 2017 : Continuous unrealized losses existing for less than 12 months Continuous unrealized losses existing for greater than 12 months Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale securities U.S. Treasury $ 144,144 $ (727 ) $ — $ — $ 144,144 $ (727 ) U.S. Government agencies 112,268 (451 ) 41,980 (115 ) 154,248 (566 ) Municipal 24,117 (138 ) 10,725 (135 ) 34,842 (273 ) Corporate notes: Financial issuers — — 35,194 (771 ) 35,194 (771 ) Other — — 997 (3 ) 997 (3 ) Mortgage-backed: Mortgage-backed securities 51,035 (6,629 ) 798,152 (23,807 ) 849,187 (30,436 ) Collateralized mortgage obligations 25,685 (195 ) 7,216 (217 ) 32,901 (412 ) Equity securities 9,177 (283 ) 6,102 (398 ) 15,279 (681 ) Total available-for-sale securities $ 366,426 $ (8,423 ) $ 900,366 $ (25,446 ) $ 1,266,792 $ (33,869 ) Held-to-maturity securities U.S. Government agencies $ 400,980 $ (12,579 ) $ — $ — $ 400,980 $ (12,579 ) Municipal 115,384 (2,159 ) — — 115,384 (2,159 ) Total held-to-maturity securities $ 516,364 $ (14,738 ) $ — $ — $ 516,364 $ (14,738 ) The Company conducts a regular assessment of its investment securities to determine whether securities are other-than-temporarily impaired considering, among other factors, the nature of the securities, credit ratings or financial condition of the issuer, the extent and duration of the unrealized loss, expected cash flows, market conditions and the Company’s ability to hold the securities through the anticipated recovery period. The Company does not consider securities with unrealized losses at September 30, 2017 to be other-than-temporarily impaired. The Company does not intend to sell these investments and it is more likely than not that the Company will not be required to sell these investments before recovery of the amortized cost bases, which may be the maturity dates of the securities. The unrealized losses within each category have occurred as a result of changes in interest rates, market spreads and market conditions subsequent to purchase. Securities with continuous unrealized losses existing for more than twelve months were primarily corporate notes and mortgage-backed securities. Unrealized losses recognized on corporate notes and mortgage-backed securities are the result of increases in yields for similar types of securities. The following table provides information as to the amount of gross gains and gross losses realized and proceeds received through the sale or call of investment securities: Three months ended September 30, Nine months ended September 30, (Dollars in thousands) 2017 2016 2017 2016 Realized gains $ 58 $ 3,429 $ 106 $ 7,466 Realized losses (19 ) (124 ) (75 ) (1,396 ) Net realized gains $ 39 $ 3,305 $ 31 $ 6,070 Other than temporary impairment charges — — — — Gains on investment securities, net $ 39 $ 3,305 $ 31 $ 6,070 Proceeds from sales and calls of available-for-sale securities $ 136,789 $ 1,114,666 $ 146,518 $ 2,186,662 Proceeds from calls of held-to-maturity securities 17 141,885 51,079 423,866 The amortized cost and fair value of securities as of September 30, 2017 , December 31, 2016 and September 30, 2016 , by contractual maturity, are shown in the following table. Contractual maturities may differ from actual maturities as borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Mortgage-backed securities determined to be available-for-sale are not included in the maturity categories in the following maturity summary as actual maturities may differ from contractual maturities because the underlying mortgages may be called or prepaid without penalties: September 30, 2017 December 31, 2016 September 30, 2016 (Dollars in thousands) Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Available-for-sale securities Due in one year or less $ 150,907 $ 150,241 $ 145,353 $ 145,062 $ 115,227 $ 115,487 Due in one to five years 282,443 282,121 321,019 320,423 141,364 141,368 Due in five to ten years 38,339 39,458 27,319 28,451 28,696 31,319 Due after ten years 8,188 8,283 34,296 34,399 10,539 10,029 Mortgage-backed 1,178,589 1,149,448 1,215,553 1,161,084 1,293,005 1,301,111 Equity securities 33,166 36,352 32,608 35,248 48,568 50,782 Total available-for-sale securities $ 1,691,632 $ 1,665,903 $ 1,776,148 $ 1,724,667 $ 1,637,399 $ 1,650,096 Held-to-maturity securities Due in one year or less $ 170 $ 171 $ — $ — $ — $ — Due in one to five years 36,914 36,734 29,794 29,416 25,927 26,023 Due in five to ten years 193,387 192,581 69,664 67,820 64,835 65,842 Due after ten years 588,869 577,550 536,247 510,366 842,005 850,801 Total held-to-maturity securities $ 819,340 $ 807,036 $ 635,705 $ 607,602 $ 932,767 $ 942,666 Securities having a fair value of $1.6 billion at September 30, 2017 as well as securities having a fair value of $1.4 billion at December 31, 2016 and September 30, 2016 were pledged as collateral for public deposits, trust deposits, Federal Home Loan Bank ("FHLB") advances, securities sold under repurchase agreements and derivatives. At September 30, 2017 , there were no securities of a single issuer, other than U.S. Government-sponsored agency securities, which exceeded 10% of shareholders’ equity.

Loans

Loans	9 Months Ended
	Sep. 30, 2017
Loans and Leases Receivable Disclosure [Abstract]
Loans	Loans The following table shows the Company’s loan portfolio by category as of the dates shown: September 30, December 31, September 30, (Dollars in thousands) 2017 2016 2016 Balance: Commercial $ 6,456,034 $ 6,005,422 $ 5,951,544 Commercial real estate 6,400,781 6,196,087 5,908,684 Home equity 672,969 725,793 742,868 Residential real estate 789,499 705,221 663,598 Premium finance receivables—commercial 2,664,912 2,478,581 2,430,233 Premium finance receivables—life insurance 3,795,474 3,470,027 3,283,359 Consumer and other 133,112 122,041 120,975 Total loans, net of unearned income, excluding covered loans $ 20,912,781 $ 19,703,172 $ 19,101,261 Covered loans 46,601 58,145 95,940 Total loans $ 20,959,382 $ 19,761,317 $ 19,197,201 Mix: Commercial 31 % 30 % 31 % Commercial real estate 31 31 31 Home equity 3 4 4 Residential real estate 3 4 3 Premium finance receivables—commercial 13 12 13 Premium finance receivables—life insurance 18 18 17 Consumer and other 1 1 1 Total loans, net of unearned income, excluding covered loans 100 % 100 % 100 % Covered loans — — — Total loans 100 % 100 % 100 % The Company’s loan portfolio is generally comprised of loans to consumers and small to medium-sized businesses located within the geographic market areas that the banks serve. The premium finance receivables portfolios are made to customers throughout the United States and Canada. The Company strives to maintain a loan portfolio that is diverse in terms of loan type, industry, borrower and geographic concentrations. Such diversification reduces the exposure to economic downturns that may occur in different segments of the economy or in different industries. Certain premium finance receivables are recorded net of unearned income. The unearned income portions of such premium finance receivables were $80.4 million at September 30, 2017 , $69.6 million at December 31, 2016 and $64.4 million at September 30, 2016 . Total loans, excluding PCI loans, include net deferred loan fees and costs and fair value purchase accounting adjustments totaling $8.0 million at September 30, 2017 , $2.6 million at December 31, 2016 and $873,000 at September 30, 2016 . PCI loans are recorded net of credit discounts. See “Acquired Loan Information at Acquisition” below. It is the policy of the Company to review each prospective credit in order to determine the appropriateness and, when required, the adequacy of security or collateral necessary to obtain when making a loan. The type of collateral, when required, will vary from liquid assets to real estate. The Company seeks to ensure access to collateral, in the event of default, through adherence to state lending laws and the Company’s credit monitoring procedures. Acquired Loan Information at Acquisition—PCI Loans As part of the Company's previous acquisitions, the Company acquired loans for which there was evidence of credit quality deterioration since origination (PCI loans) and determined that it was probable that the Company would be unable to collect all contractually required principal and interest payments. The following table presents the unpaid principal balance and carrying value for these acquired loans: September 30, 2017 December 31, 2016 (Dollars in thousands) Unpaid Principal Balance Carrying Value Unpaid Carrying PCI loans $ 406,891 $ 379,407 $ 509,446 $ 471,786 See Note 7—Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans for further discussion regarding the allowance for loan losses associated with PCI loans at September 30, 2017 . Accretable Yield Activity - PCI Loans Changes in expected cash flows may vary from period to period as the Company periodically updates its cash flow model assumptions for PCI loans. The factors that most significantly affect the estimates of gross cash flows expected to be collected, and accordingly the accretable yield, include changes in the benchmark interest rate indices for variable-rate products and changes in prepayment assumptions and loss estimates. The following table provides activity for the accretable yield of PCI loans: Three Months Ended Nine Months Ended (Dollars in thousands) September 30, September 30, September 30, September 30, Accretable yield, beginning balance $ 45,510 $ 55,630 $ 49,408 $ 63,902 Acquisitions — — 426 1,082 Accretable yield amortized to interest income (5,025 ) (6,449 ) (16,101 ) (17,105 ) Accretable yield amortized to indemnification asset/liability (1) (371 ) (1,744 ) (1,086 ) (5,539 ) Reclassification from non-accretable difference (2) 1,017 5,370 7,106 12,099 Decreases in interest cash flows due to payments and changes in interest rates (875 ) 170 503 (1,462 ) Accretable yield, ending balance (3) $ 40,256 $ 52,977 $ 40,256 $ 52,977 (1) Represents the portion of the current period accreted yield, resulting from lower expected losses, applied to reduce the loss share indemnification asset or increase the loss share indemnification liability. (2) Reclassification is the result of subsequent increases in expected principal cash flows. (3) As of September 30, 2017 , the Company estimates that the remaining accretable yield balance to be amortized to the indemnification asset or liability for the bank acquisitions is approximately $24,000 . The remainder of the accretable yield related to bank acquisitions is expected to be amortized to interest income. Accretion to interest income accounted for under ASC 310-30 totaled $5.0 million and $6.4 million in the third quarter of 2017 and 2016 , respectively. For the nine months ended September 30, 2017 and 2016 , the Company recorded accretion to interest income of $16.1 million and $17.1 million , respectively. These amounts include accretion from both covered and non-covered loans, and are both included within interest and fees on loans in the Consolidated Statements of Income.

Allowance for Loan Losses, Allo

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans	Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans The tables below show the aging of the Company’s loan portfolio at September 30, 2017 , December 31, 2016 and September 30, 2016 : As of September 30, 2017 90+ days and still accruing 60-89 days past due 30-59 days past due (Dollars in thousands) Nonaccrual Current Total Loans Loan Balances: Commercial Commercial, industrial and other $ 12,281 $ — $ 3,161 $ 13,710 $ 4,091,381 $ 4,120,533 Franchise — — — 16,719 836,997 853,716 Mortgage warehouse lines of credit — — — 312 194,058 194,370 Asset-based lending 1,141 — 1,533 4,515 889,147 896,336 Leases 509 — 281 1,194 379,410 381,394 PCI - commercial (1) — 1,489 61 — 8,135 9,685 Total commercial 13,931 1,489 5,036 36,450 6,399,128 6,456,034 Commercial real estate: Construction 1,607 — 366 2,064 669,940 673,977 Land 196 — — — 102,557 102,753 Office 5,148 — — 1,220 874,583 880,951 Industrial 1,848 — 137 438 834,062 836,485 Retail 2,200 — 3,030 3,674 925,335 934,239 Multi-family 569 — 68 3,058 861,290 864,985 Mixed use and other 3,310 — 843 3,561 1,966,601 1,974,315 PCI - commercial real estate (1) — 8,443 1,394 2,940 120,299 133,076 Total commercial real estate 14,878 8,443 5,838 16,955 6,354,667 6,400,781 Home equity 7,581 — 446 2,590 662,352 672,969 Residential real estate, including PCI 14,743 1,120 2,055 165 771,416 789,499 Premium finance receivables Commercial insurance loans 9,827 9,584 7,421 9,966 2,628,114 2,664,912 Life insurance loans — 6,740 946 6,937 3,571,388 3,586,011 PCI - life insurance loans (1) — — — — 209,463 209,463 Consumer and other, including PCI 540 221 242 685 131,424 133,112 Total loans, net of unearned income, excluding covered loans $ 61,500 $ 27,597 $ 21,984 $ 73,748 $ 20,727,952 $ 20,912,781 Covered loans 1,936 2,233 1,074 45 41,313 46,601 Total loans, net of unearned income $ 63,436 $ 29,830 $ 23,058 $ 73,793 $ 20,769,265 $ 20,959,382 (1) PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. Loan agings are based upon contractually required payments. As of December 31, 2016 90+ days and still accruing 60-89 days past due 30-59 days past due (Dollars in thousands) Nonaccrual Current Total Loans Loan Balances: Commercial Commercial, industrial and other $ 13,441 $ 174 $ 2,341 $ 11,779 $ 3,716,977 $ 3,744,712 Franchise — — — 493 869,228 869,721 Mortgage warehouse lines of credit — — — — 204,225 204,225 Asset-based lending 1,924 — 135 1,609 871,402 875,070 Leases 510 — — 1,331 293,073 294,914 PCI - commercial (1) — 1,689 100 2,428 12,563 16,780 Total commercial 15,875 1,863 2,576 17,640 5,967,468 6,005,422 Commercial real estate Construction 2,408 — — 1,824 606,007 610,239 Land 394 — 188 — 104,219 104,801 Office 4,337 — 4,506 1,232 857,599 867,674 Industrial 7,047 — 4,516 2,436 756,602 770,601 Retail 597 — 760 3,364 907,872 912,593 Multi-family 643 — 322 1,347 805,312 807,624 Mixed use and other 6,498 — 1,186 12,632 1,931,859 1,952,175 PCI - commercial real estate (1) — 16,188 3,775 8,888 141,529 170,380 Total commercial real estate 21,924 16,188 15,253 31,723 6,110,999 6,196,087 Home equity 9,761 — 1,630 6,515 707,887 725,793 Residential real estate, including PCI 12,749 1,309 936 8,271 681,956 705,221 Premium finance receivables Commercial insurance loans 14,709 7,962 5,646 14,580 2,435,684 2,478,581 Life insurance loans — 3,717 17,514 16,204 3,182,935 3,220,370 PCI - life insurance loans (1) — — — — 249,657 249,657 Consumer and other, including PCI 439 207 100 887 120,408 122,041 Total loans, net of unearned income, excluding covered loans $ 75,457 $ 31,246 $ 43,655 $ 95,820 $ 19,456,994 $ 19,703,172 Covered loans 2,121 2,492 225 1,553 51,754 58,145 Total loans, net of unearned income $ 77,578 $ 33,738 $ 43,880 $ 97,373 $ 19,508,748 $ 19,761,317 As of September 30, 2016 90+ days and still accruing 60-89 days past due 30-59 days past due (Dollars in thousands) Nonaccrual Current Total Loans Loan Balances: Commercial Commercial, industrial and other $ 15,809 $ — $ 7,324 $ 8,987 $ 3,573,396 $ 3,605,516 Franchise — — 458 1,626 872,661 874,745 Mortgage warehouse lines of credit — — — — 309,632 309,632 Asset-based lending 234 — 3,772 3,741 837,972 845,719 Leases 375 — 239 — 299,339 299,953 PCI - commercial (1) — 1,783 — 1,036 13,160 15,979 Total commercial 16,418 1,783 11,793 15,390 5,906,160 5,951,544 Commercial real estate: Construction 400 — — 3,775 447,302 451,477 Land 1,208 — 787 300 105,406 107,701 Office 3,609 — 6,457 8,062 865,954 884,082 Industrial 9,967 — 940 2,961 753,636 767,504 Retail 909 — 1,340 8,723 884,369 895,341 Multi-family 90 — 3,051 2,169 789,645 794,955 Mixed use and other 6,442 — 2,157 5,184 1,837,724 1,851,507 PCI - commercial real estate (1) — 21,433 1,509 4,066 129,109 156,117 Total commercial real estate 22,625 21,433 16,241 35,240 5,813,145 5,908,684 Home equity 9,309 — 1,728 3,842 727,989 742,868 Residential real estate, including PCI 12,205 1,496 2,232 1,088 646,577 663,598 Premium finance receivables Commercial insurance loans 14,214 7,754 6,968 10,291 2,391,006 2,430,233 Life insurance loans — — 9,960 3,717 3,006,795 3,020,472 PCI - life insurance loans (1) — — — — 262,887 262,887 Consumer and other, including PCI 543 124 204 871 119,233 120,975 Total loans, net of unearned income, excluding covered loans $ 75,314 $ 32,590 $ 49,126 $ 70,439 $ 18,873,792 $ 19,101,261 Covered loans 2,331 4,806 1,545 2,456 84,802 95,940 Total loans, net of unearned income $ 77,645 $ 37,396 $ 50,671 $ 72,895 $ 18,958,594 $ 19,197,201 (1) PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. Loan agings are based upon contractually required payments. The Company's ability to manage credit risk depends in large part on our ability to properly identify and manage problem loans. To do so, the Company operates a credit risk rating system under which our credit management personnel assign a credit risk rating (1 to 10 rating) to each loan at the time of origination and review loans on a regular basis. Each loan officer is responsible for monitoring his or her loan portfolio, recommending a credit risk rating for each loan in his or her portfolio and ensuring the credit risk ratings are appropriate. These credit risk ratings are then ratified by the bank’s chief credit officer and/or concurrence credit officer. Credit risk ratings are determined by evaluating a number of factors including: a borrower’s financial strength, cash flow coverage, collateral protection and guarantees. The Company’s Problem Loan Reporting system automatically includes all loans with credit risk ratings of 6 through 9. This system is designed to provide an on-going detailed tracking mechanism for each problem loan. Once management determines that a loan has deteriorated to a point where it has a credit risk rating of 6 or worse, the Company’s Managed Asset Division performs an overall credit and collateral review. As part of this review, all underlying collateral is identified and the valuation methodology is analyzed and tracked. As a result of this initial review by the Company’s Managed Asset Division, the credit risk rating is reviewed and a portion of the outstanding loan balance may be deemed uncollectible or an impairment reserve may be established. The Company’s impairment analysis utilizes an independent re-appraisal of the collateral (unless such a third-party evaluation is not possible due to the unique nature of the collateral, such as a closely-held business or thinly traded securities). In the case of commercial real estate collateral, an independent third party appraisal is ordered by the Company’s Real Estate Services Group to determine if there has been any change in the underlying collateral value. These independent appraisals are reviewed by the Real Estate Services Group and sometimes by independent third party valuation experts and may be adjusted depending upon market conditions. Through the credit risk rating process, loans are reviewed to determine if they are performing in accordance with the original contractual terms. If the borrower has failed to comply with the original contractual terms, further action may be required by the Company, including a downgrade in the credit risk rating, movement to non-accrual status, a charge-off or the establishment of a specific impairment reserve. If a loan amount, or portion thereof, is determined to be uncollectible, the loan’s credit risk rating is immediately downgraded to an 8 or 9 and the uncollectible amount is charged-off. Any loan that has a partial charge-off continues to be assigned a credit risk rating of an 8 or 9 for the duration of time that a balance remains outstanding. The Company undertakes a thorough and ongoing analysis to determine if additional impairment and/or charge-offs are appropriate and to begin a workout plan for the credit to minimize actual losses. If, based on current information and events, it is probable that the Company will be unable to collect all amounts due to it according to the contractual terms of the loan agreement, a specific impairment reserve is established. In determining the appropriate charge-off for collateral-dependent loans, the Company considers the results of appraisals for the associated collateral. Non-performing loans include all non-accrual loans (8 and 9 risk ratings) as well as loans 90 days past due and still accruing interest, excluding PCI and covered loans. The remainder of the portfolio is considered performing under the contractual terms of the loan agreement. The following table presents the recorded investment based on performance of loans by class, excluding covered loans, per the most recent analysis at September 30, 2017 , December 31, 2016 and September 30, 2016 : Performing Non-performing Total (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, September 30, December 31, September 30, Loan Balances: Commercial Commercial, industrial and other $ 4,108,252 $ 3,731,097 $ 3,589,707 $ 12,281 $ 13,615 $ 15,809 $ 4,120,533 $ 3,744,712 $ 3,605,516 Franchise 853,716 869,721 874,745 — — — 853,716 869,721 874,745 Mortgage warehouse lines of credit 194,370 204,225 309,632 — — — 194,370 204,225 309,632 Asset-based lending 895,195 873,146 845,485 1,141 1,924 234 896,336 875,070 845,719 Leases 380,885 294,404 299,578 509 510 375 381,394 294,914 299,953 PCI - commercial (1) 9,685 16,780 15,979 — — — 9,685 16,780 15,979 Total commercial 6,442,103 5,989,373 5,935,126 13,931 16,049 16,418 6,456,034 6,005,422 5,951,544 Commercial real estate Construction 672,370 607,831 451,077 1,607 2,408 400 673,977 610,239 451,477 Land 102,557 104,407 106,493 196 394 1,208 102,753 104,801 107,701 Office 875,803 863,337 880,473 5,148 4,337 3,609 880,951 867,674 884,082 Industrial 834,637 763,554 757,537 1,848 7,047 9,967 836,485 770,601 767,504 Retail 932,039 911,996 894,432 2,200 597 909 934,239 912,593 895,341 Multi-family 864,416 806,981 794,865 569 643 90 864,985 807,624 794,955 Mixed use and other 1,971,005 1,945,677 1,845,065 3,310 6,498 6,442 1,974,315 1,952,175 1,851,507 PCI - commercial real estate (1) 133,076 170,380 156,117 — — — 133,076 170,380 156,117 Total commercial real estate 6,385,903 6,174,163 5,886,059 14,878 21,924 22,625 6,400,781 6,196,087 5,908,684 Home equity 665,388 716,032 733,559 7,581 9,761 9,309 672,969 725,793 742,868 Residential real estate, including PCI 774,756 692,472 651,393 14,743 12,749 12,205 789,499 705,221 663,598 Premium finance receivables Commercial insurance loans 2,645,501 2,455,910 2,408,265 19,411 22,671 21,968 2,664,912 2,478,581 2,430,233 Life insurance loans 3,579,271 3,216,653 3,020,472 6,740 3,717 — 3,586,011 3,220,370 3,020,472 PCI - life insurance loans (1) 209,463 249,657 262,887 — — — 209,463 249,657 262,887 Consumer and other, including PCI 132,413 121,458 120,372 699 583 603 133,112 122,041 120,975 Total loans, net of unearned income, excluding covered loans $ 20,834,798 $ 19,615,718 $ 19,018,133 $ 77,983 $ 87,454 $ 83,128 $ 20,912,781 $ 19,703,172 $ 19,101,261 (1) PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. See Note 6 - Loans for further discussion of these purchased loans. A summary of activity in the allowance for credit losses by loan portfolio (excluding covered loans) for the three and nine months ended September 30, 2017 and 2016 is as follows: Three months ended September 30, 2017 Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivables Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Commercial Allowance for credit losses Allowance for loan losses at beginning of period $ 52,358 $ 52,339 $ 11,134 $ 6,143 $ 6,352 $ 1,265 $ 129,591 Other adjustments (2 ) (38 ) — (31 ) 32 — (39 ) Reclassification from allowance for unfunded lending-related commitments 500 (406 ) — — — — 94 Charge-offs (2,265 ) (989 ) (968 ) (267 ) (1,716 ) (213 ) (6,418 ) Recoveries 801 323 178 55 499 93 1,949 Provision for credit losses 4,343 811 212 757 1,386 433 7,942 Allowance for loan losses at period end $ 55,735 $ 52,040 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 133,119 Allowance for unfunded lending-related commitments at period end $ — $ 1,276 $ — $ — $ — $ — $ 1,276 Allowance for credit losses at period end $ 55,735 $ 53,316 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 134,395 Individually evaluated for impairment $ 4,568 $ 1,184 $ 691 $ 758 $ — $ 34 $ 7,235 Collectively evaluated for impairment 50,623 52,048 9,865 5,813 6,553 1,544 126,446 Loans acquired with deteriorated credit quality 544 84 — 86 — — 714 Loans at period end Individually evaluated for impairment $ 18,086 $ 31,698 $ 7,729 $ 21,263 $ — $ 544 $ 79,320 Collectively evaluated for impairment 6,428,263 6,236,007 665,240 735,185 6,250,923 131,581 20,447,199 Loans acquired with deteriorated credit quality 9,685 133,076 — 3,637 209,463 987 356,848 Loans held at fair value — — — 29,414 — — 29,414 Three months ended September 30, 2016 Commercial Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivables Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Allowance for credit losses Allowance for loan losses at beginning of period $ 41,654 $ 46,824 $ 11,383 $ 5,405 $ 7,814 $ 1,276 $ 114,356 Other adjustments (35 ) (57 ) — (10 ) (10 ) — (112 ) Reclassification from allowance for unfunded lending-related commitments (500 ) (79 ) — — — — (579 ) Charge-offs (3,469 ) (382 ) (574 ) (134 ) (1,959 ) (389 ) (6,907 ) Recoveries 176 364 65 61 456 72 1,194 Provision for credit losses 5,212 1,678 810 781 974 286 9,741 Allowance for loan losses at period end $ 43,038 $ 48,348 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 117,693 Allowance for unfunded lending-related commitments at period end $ 500 $ 1,148 $ — $ — $ — $ — $ 1,648 Allowance for credit losses at period end $ 43,538 $ 49,496 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 119,341 Individually evaluated for impairment $ 2,554 $ 2,491 $ 964 $ 1,166 $ — $ 192 $ 7,367 Collectively evaluated for impairment 40,252 46,983 10,720 4,867 7,275 1,053 111,150 Loans acquired with deteriorated credit quality 732 22 — 70 — — 824 Loans at period end Individually evaluated for impairment $ 19,133 $ 45,290 $ 9,309 $ 17,040 $ — $ 602 $ 91,374 Collectively evaluated for impairment 5,916,432 5,707,277 733,559 625,030 5,450,705 119,162 18,552,165 Loans acquired with deteriorated credit quality 15,979 156,117 — 3,925 262,887 1,211 440,119 Loans held at fair value — — — 17,603 — — 17,603 Nine months ended September 30, 2017 Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivable Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Commercial Allowance for credit losses Allowance for loan losses at beginning of period $ 44,493 $ 51,422 $ 11,774 $ 5,714 $ 7,625 $ 1,263 $ 122,291 Other adjustments (23 ) (121 ) — (38 ) 57 — (125 ) Reclassification from allowance for unfunded lending-related commitments 500 (438 ) — — — — 62 Charge-offs (3,819 ) (3,235 ) (3,224 ) (742 ) (5,021 ) (522 ) (16,563 ) Recoveries 1,635 1,153 387 287 1,515 267 5,244 Provision for credit losses 12,949 3,259 1,619 1,436 2,377 570 22,210 Allowance for loan losses at period end $ 55,735 $ 52,040 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 133,119 Allowance for unfunded lending-related commitments at period end $ — $ 1,276 $ — $ — $ — $ — $ 1,276 Allowance for credit losses at period end $ 55,735 $ 53,316 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 134,395 Nine months ended September 30, 2016 Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivable Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Commercial Allowance for credit losses Allowance for loan losses at beginning of period $ 36,135 $ 43,758 $ 12,012 $ 4,734 $ 7,233 $ 1,528 $ 105,400 Other adjustments (103 ) (203 ) — (49 ) 31 — (324 ) Reclassification from allowance for unfunded lending-related commitments (500 ) (200 ) — — — — (700 ) Charge-offs (4,861 ) (1,555 ) (3,672 ) (1,320 ) (6,350 ) (720 ) (18,478 ) Recoveries 926 1,029 184 204 1,876 143 4,362 Provision for credit losses 11,441 5,519 3,160 2,534 4,485 294 27,433 Allowance for loan losses at period end $ 43,038 $ 48,348 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 117,693 Allowance for unfunded lending-related commitments at period end $ 500 $ 1,148 $ — $ — $ — $ — $ 1,648 Allowance for credit losses at period end $ 43,538 $ 49,496 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 119,341 A summary of activity in the allowance for covered loan losses for the three and nine months ended September 30, 2017 and 2016 is as follows: Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, (Dollars in thousands) 2017 2016 2017 2016 Balance at beginning of period $ 1,074 $ 2,412 $ 1,322 $ 3,026 Provision for covered loan losses before benefit attributable to FDIC loss share agreements (225 ) (847 ) (1,063 ) (3,495 ) Benefit attributable to FDIC loss share agreements 180 677 850 2,796 Net provision for covered loan losses (45 ) (170 ) (213 ) (699 ) Increase in FDIC indemnification liability (180 ) (677 ) (850 ) (2,796 ) Loans charged-off (155 ) (918 ) (491 ) (1,291 ) Recoveries of loans charged-off 64 775 990 3,182 Net (charge-offs) recoveries (91 ) (143 ) 499 1,891 Balance at end of period $ 758 $ 1,422 $ 758 $ 1,422 In conjunction with FDIC-assisted transactions, the Company entered into loss share agreements with the FDIC. Additional expected losses, to the extent such expected losses result in the recognition of an allowance for loan losses, will increase the FDIC loss share asset or reduce any FDIC loss share liability. The allowance for loan losses for loans acquired in FDIC-assisted transactions is determined without giving consideration to the amounts recoverable through loss share agreements (since the loss share agreements are separately accounted for and thus presented “gross” on the balance sheet). On the Consolidated Statements of Income, the provision for credit losses is reported net of changes in the amount recoverable under the loss share agreements during the period subject to loss share agreement. Reductions to expected losses, to the extent such reductions to expected losses are the result of an improvement to the actual or expected cash flows from the covered assets, will reduce the FDIC loss share asset or increase any FDIC loss share liability. Additions to expected losses will require an increase to the allowance for covered loan losses, and a corresponding increase to the FDIC loss share asset or reduction to any FDIC loss share liability. See “FDIC-Assisted Transactions” within Note 3 – Business Combinations for more detail. On October 16, 2017, the Company entered into agreements with the FDIC that terminate all existing loss share agreements with the FDIC. As a result, the allowance for covered loan losses previously measured will be included within the allowance for credit losses, excluding covered loans, presented above for subsequent periods. See Note 17 - Subsequent Events for further discussion of the termination of FDIC loss share agreements. Impaired Loans A summary of impaired loans, including troubled debt restructurings ("TDRs"), is as follows: September 30, December 31, September 30, (Dollars in thousands) 2017 2016 2016 Impaired loans (included in non-performing and TDRs): Impaired loans with an allowance for loan loss required (1) $ 30,864 $ 33,146 $ 39,022 Impaired loans with no allowance for loan loss required 47,730 57,370 51,518 Total impaired loans (2) $ 78,594 $ 90,516 $ 90,540 Allowance for loan losses related to impaired loans $ 7,218 $ 6,377 $ 6,836 TDRs $ 33,183 $ 41,708 $ 44,276 (1) These impaired loans require an allowance for loan losses because the estimated fair value of the loans or related collateral is less than the recorded investment in the loans. (2) Impaired loans are considered by the Company to be non-accrual loans, TDRs or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest. The following tables present impaired loans by loan class, excluding covered loans, for the periods ended as follows: For the Nine Months Ended As of September 30, 2017 September 30, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with a related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 7,312 $ 8,458 $ 4,191 $ 8,390 $ 407 Asset-based lending 588 589 161 588 21 Leases 2,440 2,444 215 2,539 91 Commercial real estate Construction 1,607 2,408 94 2,319 93 Land — — — — — Office 2,225 2,291 570 2,280 94 Industrial 408 408 75 415 19 Retail 5,932 6,072 158 5,998 191 Multi-family 1,239 1,239 8 1,250 33 Mixed use and other 1,537 1,695 263 1,580 60 Home equity 1,511 1,721 691 1,528 53 Residential real estate 5,842 6,154 758 5,842 177 Consumer and other 223 224 34 225 10 Impaired loans with no related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 5,995 $ 7,260 $ — $ 6,662 $ 294 Asset-based lending 553 553 — 728 31 Leases 817 817 — 862 38 Commercial real estate Construction 1,504 1,504 — 1,524 49 Land 3,968 4,217 — 4,110 136 Office 3,400 3,585 — 3,565 147 Industrial 1,440 2,729 — 2,885 183 Retail 1,978 1,988 — 2,008 103 Multi-family 569 653 — 571 23 Mixed use and other 5,546 6,267 — 5,745 241 Home equity 6,218 9,523 — 7,231 339 Residential real estate 15,421 17,859 — 15,726 575 Consumer and other 321 433 — 334 16 Total impaired loans, net of unearned income $ 78,594 $ 91,091 $ 7,218 $ 84,905 $ 3,424 For the Twelve Months Ended As of December 31, 2016 December 31, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with a related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 2,601 $ 2,617 $ 1,079 $ 2,649 $ 134 Asset-based lending 233 235 26 235 10 Leases 2,441 2,443 107 2,561 128 Commercial real estate Construction 5,302 5,302 86 5,368 164 Land 1,283 1,283 1 1,303 47 Office 2,687 2,697 324 2,797 137 Industrial 5,207 5,843 1,810 7,804 421 Retail 1,750 1,834 170 2,039 101 Multi-family — — — — — Mixed use and other 3,812 4,010 592 4,038 195 Home equity 1,961 1,873 1,233 1,969 75 Residential real estate 5,752 6,327 849 5,816 261 Consumer and other 117 121 100 131 7 Impaired loans with no related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 12,534 $ 14,704 $ — $ 14,944 $ 948 Asset-based lending 1,691 2,550 — 8,467 377 Leases 873 873 — 939 56 Commercial real estate Construction 4,003 4,003 — 4,161 81 Land 3,034 3,503 — 3,371 142 Office 3,994 5,921 — 4,002 323 Industrial 2,129 2,436 — 2,828 274 Retail — — — — — Multi-family 1,903 1,987 — 1,825 84 Mixed use and other 6,815 7,388 — 6,912 397 Home equity 8,033 10,483 — 8,830 475 Residential real estate 11,983 14,124 — 12,041 622 Consumer and other 378 489 — 393 26 Total impaired loans, net of unearned income $ 90,516 $ 103,046 $ 6,377 $ 105,423 $ 5,485 For the Nine Months Ended As of September 30, 2016 September 30, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with a related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 5,426 $ 5,434 $ 1,887 $ 5,487 $ 212 Asset-based lending 234 235 44 235 7 Leases 375 375 116 388 14 Commercial real estate Construction — — — — — Land 2,620 2,620 44 2,670 80 Office 1,697 2,361 182 1,722 79 Industrial 6,855 7,338 1,388 7,069 284 Retail 6,605 6,623 240 6,668 160 Multi-family 1,266 1,266 8 1,134 29 Mixed use and other 5,437 5,511 605 5,452 198 Home equity 2,373 2,457 964 2,404 63 Residential real estate 5,942 6,428 1,166 5,807 190 Consumer and other 192 192 192 194 8 Impaired loans with no related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 12,669 $ 16,261 $ — $ 14,745 $ 717 Asset-based lending — — — — — Leases — — — — — Commercial real estate Construction 1,995 1,995 — 2,273 94 Land 3,864 8,088 — 4,316 408 Office 4,980 6,243 — 4,978 260 Industrial 3,508 3,827 — 3,574 200 Retail 805 913 — 936 36 Multi-family 89 174 — 109 5 Mixed use and other 5,164 5,712 — 5,300 236 Home equity 6,936 9,108 — 7,736 320 Residential real estate 11,098 13,077 — 11,125 445 Consumer and other 410 520 — 428 21 Total impaired loans, net of unearned income $ 90,540 $ 106,758 $ 6,836 $ 94,750 $ 4,066 TDRs At September 30, 2017 , the Company had $33.2 million in loans modified in TDRs. The $33.2 million in TDRs represents 78 credits in which economic concessions were granted to certain borrowers to better align the terms of their loans with their current ability to pay. The Company’s approach to restructuring loans, excluding PCI loans, is built on its credit risk rating system which requires credit management personnel to assign a credit risk rating to each loan. In each case, the loan officer is responsible for recommending a credit risk rating for each loan and ensuring the credit risk ratings are appropriate. These credit risk ratings are then reviewed and approved by the bank’s chief credit officer and/or concurrence credit officer. Credit risk ratings are determined by evaluating a number of factors including a borrower’s financial strength, cash flow coverage, collateral protection and guarantees. The Company’s credit risk rating scale is one through ten with higher scores indicating higher risk. In the case of loans rated six or worse following modification, the Company’s Managed Assets Division evaluates the loan and the credit risk rating and determines that the loan has been restructured to be reasonably assured of repayment and of performance according to the modified terms and is supported by a current, well-documented credit assessment of the borrower’s financial condition and prospects for repayment under the revised terms. A modification of a loan, excluding PCI loans, with an existing credit risk rating of 6 or worse or a modification of any other credit, which will result in a restructured credit risk rating of six or worse, must be reviewed for possible TDR classification. In that event, our Managed Assets Division conducts an overall credit and collateral review. A modification of these loans is considered to be a TDR if both (1) the borrower is experiencing financial difficulty and (2) for economic or legal reasons, the bank grants a concession to a borrower that it would not otherwise consider. The modification of a loan, excluding PCI loans, where the credit risk rating is 5 or better both before and after such modification is not considered to be a TDR. Based on the Company’s credit risk rating system, it considers that borrowers whose credit risk rating is 5 or better are not experiencing financial difficulties and therefore, are not considered TDRs. All credits determined to be a TDR will continue to be classified as a TDR in all subsequent periods, unless the borrower has been in compliance with the loan’s modified terms for a period of six months (including over a calendar year-end) and the current interest rate represents a market rate at the time of restructuring. The Managed Assets Division, in consultation with the respective loan officer, determines whether the modified interest rate represented a current market rate at the time of restructuring. Using knowledge of current market conditions and rates, competitive pricing on recent loan originations, and an assessment of various characteristics of the modified loan (including collateral position and payment history), an appropriate market rate for a new borrower with similar risk is determined. If the modified interest rate meets or exceeds this market rate for a new borrower with similar risk, the modified interest rate represents a market rate at the time of restructuring. Additionally, before removing a loan from TDR classification, a review of the current or previously measured impairment on the loan and any concerns related to future performance by the borrower is conducted. If concerns exist about the future ability of the borrower to meet its obligations under the loans based on a credit review by the Managed Assets Division, the TDR classification is not removed from the loan. TDRs are reviewed at the time of the modification and on a quarterly basis to determine if a specific reserve is necessary. The carrying amount of the loan is compared to the expected payments to be received, discounted at the loan's original rate, or for collateral dependent loans, to the fair value of the collateral. Any shortfall is recorded as a specific reserve. The Company, in accordance with ASC 310-10, continues to individually measure impairment of these loans after the TDR classification is removed. Each TDR was reviewed for impairment at September 30, 2017 and approximately $1.2 million of impairment was present and appropriately reserved for through the Company’s normal reserving methodology in the Company’s allowance for loan losses. For TDRs in which impairment is calculated by the present value of future cash flows, the Company records interest income representing the decrease in impairment resulting from the passage of time during the respective period, which differs from interest income from contractually required interest on these specific loans. During the three months ended September 30, 2017 and 2016 , the Company recorded $68,000 and $98,000 , respectively, of interest income, which was reflected as a decrease in impairment. For the nine months ended September 30, 2017 and 2016 , the Company recorded $172,000 and $323,000 , respectively, of interest income, which was reflected as a decrease in impairment. TDRs may arise in which, due to financial difficulties experienced by the borrower, the Company obtains through physical possession one or more collateral assets in satisfaction of all or part of an existing credit. Once possession is obtained, the Company reclassifies the appropriate portion of the remaining balance of the credit from loans to OREO, which is included within other assets in the Consolidated Statements of Condition. For any residential real estate property collateralizing a consumer mortgage loan, the Company is considered to possess the related collateral only if legal title is obtained upon completion of foreclosure, or the borrower conveys all interest in the residential real estate property to the Company through completion of a deed in lieu of foreclosure or similar legal agreement. Excluding covered OREO, at September 30, 2017 , the Company had $7.9 million of foreclosed residential real estate properties included within OREO. Furthermore, the recorded investment in residential mortgage loans secured by residential real estate properties for which foreclosure proceedings are in process totaled $12.1 million at September 30, 2017 . The tables below present a summary of the post-modification balance of loans restructured during the three and nine months ended September 30, 2017 and 2016 , respectively, which represent TDRs: Three months ended September 30, 2017 (Dollars in thousands) Total (1)(2) Extension at Below Market (2) Reduction of Interest Rate (2) Modification to Interest-only Payments (2) Forgiveness of Debt (2) Count Balance Count Balance Count Balance Count Balance Count Balance Commercial Commercial, in

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets A summary of the Company’s goodwill assets by business segment is presented in the following table: (Dollars in thousands) January 1, 2017 Goodwill Acquired Impairment Loss Goodwill Adjustments September 30, Community banking $ 427,781 $ 999 $ — $ 685 $ 429,465 Specialty finance 38,692 — — 1,750 40,442 Wealth management 32,114 — — — 32,114 Total $ 498,587 $ 999 $ — $ 2,435 $ 502,021 The community banking segment's goodwill increased $1.7 million in the first nine months of 2017 primarily as a result of the acquisition of AHM and subsequent purchase adjustments related to the acquisition of FCFC. The specialty finance segment's goodwill increased $1.8 million in the first nine months of 2017 as a result of foreign currency translation adjustments related to the Canadian acquisitions. At June 30, 2017, the Company utilized a quantitative approach for its annual goodwill impairment test of the community banking segment and determined that no impairment existed at that time. At December 31, 2016, the Company utilized a quantitative approach for its annual goodwill impairment tests of the specialty finance and wealth management segments and determined that no impairment existed at that time. At each reporting date between annual goodwill impairment tests, the Company considers potential indicators of impairment. As of September 30, 2017 , the Company identified no such indicators of goodwill impairment for each business segment. A summary of finite-lived intangible assets as of the dates shown and the expected amortization as of September 30, 2017 is as follows: (Dollars in thousands) September 30, December 31, September 30, Community banking segment: Core deposit intangibles: Gross carrying amount $ 37,272 $ 37,272 $ 34,998 Accumulated amortization (24,550 ) (21,614 ) (20,598 ) Net carrying amount $ 12,722 $ 15,658 $ 14,400 Specialty finance segment: Customer list intangibles: Gross carrying amount $ 1,972 $ 1,800 $ 1,800 Accumulated amortization (1,258 ) (1,159 ) (1,129 ) Net carrying amount $ 714 $ 641 $ 671 Wealth management segment: Customer list and other intangibles: Gross carrying amount $ 7,940 $ 7,940 $ 7,940 Accumulated amortization (2,725 ) (2,388 ) (2,275 ) Net carrying amount $ 5,215 $ 5,552 $ 5,665 Total other intangible assets, net $ 18,651 $ 21,851 $ 20,736 Estimated amortization Actual in nine months ended September 30, 2017 $ 3,373 Estimated remaining in 2017 1,027 Estimated—2018 3,796 Estimated—2019 3,223 Estimated—2020 2,597 Estimated—2021 2,056 The core deposit intangibles recognized in connection with prior bank acquisitions are amortized over a ten -year period on an accelerated basis. The customer list intangibles recognized in connection with the purchase of life insurance premium finance assets in 2009 are being amortized over an 18 -year period on an accelerated basis while the customer list intangibles recognized in connection with prior acquisitions within the wealth management segment are being amortized over a ten -year period on a straight-line basis. Total amortization expense associated with finite-lived intangibles totaled approximately $3.4 million and $3.6 million for the nine months ended September 30, 2017 and 2016 , respectively.

Deposits

Deposits	9 Months Ended
	Sep. 30, 2017
Deposits [Abstract]
Deposits	Deposits The following table is a summary of deposits as of the dates shown: (Dollars in thousands) September 30, December 31, September 30, Balance: Non-interest bearing $ 6,502,409 $ 5,927,377 $ 5,711,042 NOW and interest bearing demand deposits 2,273,025 2,624,442 2,552,611 Wealth management deposits 2,171,758 2,209,617 2,283,233 Money market 4,607,995 4,441,811 4,421,631 Savings 2,673,201 2,180,482 1,977,661 Time certificates of deposit 4,666,675 4,274,903 4,201,477 Total deposits $ 22,895,063 $ 21,658,632 $ 21,147,655 Mix: Non-interest bearing 28 % 27 % 27 % NOW and interest bearing demand deposits 10 12 12 Wealth management deposits 10 10 11 Money market 20 21 21 Savings 12 10 9 Time certificates of deposit 20 20 20 Total deposits 100 % 100 % 100 % Wealth management deposits represent deposit balances (primarily money market accounts) at the Company’s subsidiary banks from brokerage customers of Wayne Hummer Investments, LLC ("WHI"), trust and asset management customers of Company and brokerage customers from unaffiliated companies.

FHLB Advances, Other Borrowings

FHLB Advances, Other Borrowings and Subordinated Notes	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
FHLB Advances, Other Borrowings and Subordinated Notes	FHLB Advances, Other Borrowings and Subordinated Notes The following table is a summary of FHLB advances, other borrowings and subordinated notes as of the dates shown: (Dollars in thousands) September 30, December 31, September 30, FHLB advances $ 468,962 $ 153,831 $ 419,632 Other borrowings: Notes payable 41,216 52,445 56,191 Short-term borrowings 19,959 61,809 33,173 Other 49,502 18,154 18,360 Secured borrowings 141,003 130,078 133,642 Total other borrowings 251,680 262,486 241,366 Subordinated notes 139,052 138,971 138,943 Total FHLB advances, other borrowings and subordinated notes $ 859,694 $ 555,288 $ 799,941 FHLB Advances FHLB advances consist of obligations of the banks and are collateralized by qualifying commercial and residential real estate and home equity loans and certain securities. FHLB advances are stated at par value of the debt adjusted for unamortized prepayment fees paid at the time of prior restructurings of FHLB advances and unamortized fair value adjustments recorded in connection with advances acquired through acquisitions. Notes Payable At September 30, 2017 , notes payable represented a $41.2 million term facility ("Term Facility"), which is part of a $150.0 million loan agreement ("Credit Agreement") with unaffiliated banks dated December 15, 2014 . The Credit Agreement consists of the Term Facility with an original outstanding balance of $75.0 million and a $75.0 million revolving credit facility ("Revolving Credit Facility"). At September 30, 2017 , the Company had a balance of $41.2 million compared to $52.4 million at December 31, 2016 and $56.2 million at September 30, 2016 under the Term Facility. The Term Facility is stated at par of the current outstanding balance of the debt adjusted for unamortized costs paid by the Company in relation to the debt issuance. The Company was contractually required to borrow the entire amount of the Term Facility on June 15, 2015 and all such borrowings must be repaid by June 15, 2020 . Beginning September 30, 2015 , the Company was required to make straight-line quarterly amortizing payments on the Term Facility. At September 30, 2017 , December 31, 2016 and September 30, 2016 , the Company had no outstanding balance under the Revolving Credit Facility. As no outstanding balance exists on the Revolving Credit Facility, unamortized costs paid by the Company in relation to the issuance of this debt are classified in other assets on the Consolidated Statements of Condition. In December 2015 , the Company amended the Credit Agreement, effectively extending the maturity date on the Revolving Credit Facility from December 14, 2015 to December 12, 2016 . In December 2016, the Company again amended the Credit Agreement, effectively extending the maturity date on the Revolving Credit Facility from December 12, 2016 to December 11, 2017 . Borrowings under the Credit Agreement that are considered “Base Rate Loans” bear interest at a rate equal to the sum of (1) 50 basis points (in the case of a borrowing under the Revolving Credit Facility) or 75 basis points (in the case of a borrowing under the Term Facility) plus (2) the highest of (a) the federal funds rate plus 50 basis points , (b) the lender's prime rate, and (c) the Eurodollar Rate (as defined below) that would be applicable for an interest period of one month plus 100 basis points . Borrowings under the agreement that are considered “Eurodollar Rate Loans” bear interest at a rate equal to the sum of (1) 150 basis points (in the case of a borrowing under the Revolving Credit Facility) or 175 basis points (in the case of a borrowing under the Term Facility) plus (2) the LIBOR rate for the applicable period, as adjusted for statutory reserve requirements for eurocurrency liabilities (the “Eurodollar Rate”). A commitment fee is payable quarterly equal to 0.20% of the actual daily amount by which the lenders' commitment under the Revolving Credit Facility exceeded the amount outstanding under such facility. Borrowings under the Credit Agreement are secured by pledges of and first priority perfected security interests in the Company's equity interest in its bank subsidiaries and contain several restrictive covenants, including the maintenance of various capital adequacy levels, asset quality and profitability ratios, and certain restrictions on dividends and other indebtedness. At September 30, 2017 , the Company was in compliance with all such covenants. The Revolving Credit Facility and the Term Facility are available to be utilized, as needed, to provide capital to fund continued growth at the Company’s banks and to serve as an interim source of funds for acquisitions, common stock repurchases or other general corporate purposes. Short-term Borrowings Short-term borrowings include securities sold under repurchase agreements and federal funds purchased. These borrowings totaled $20.0 million at September 30, 2017 compared to $61.8 million at December 31, 2016 and $33.2 million at September 30, 2016 . At September 30, 2017 , December 31, 2016 and September 30, 2016 , securities sold under repurchase agreements represent $20.0 million , $61.8 million and $33.2 million , respectively, of customer sweep accounts in connection with master repurchase agreements at the banks. The Company records securities sold under repurchase agreements at their gross value and does not offset positions on the Consolidated Statements of Condition. As of September 30, 2017 , the Company had pledged securities related to its customer balances in sweep accounts of $60.0 million . Securities pledged for customer balances in sweep accounts and short-term borrowings from brokers are maintained under the Company’s control and consist of U.S. Government agency and mortgage-backed securities. These securities are included in the available-for-sale and held-to-maturity securities portfolios as reflected on the Company’s Consolidated Statements of Condition. The following is a summary of these securities pledged as of September 30, 2017 disaggregated by investment category and maturity of the related customer sweep account, and reconciled to the outstanding balance of securities sold under repurchase agreements: (Dollars in thousands) Overnight Sweep Collateral Available-for-sale securities pledged U.S. Treasury $ 24,830 Mortgage-backed securities 10,162 Held-to-maturity securities pledged U.S. Government agencies 25,000 Total collateral pledged $ 59,992 Excess collateral 40,033 Securities sold under repurchase agreements $ 19,959 Other Borrowings Other borrowings at September 30, 2017 represent a fixed-rate promissory note issued by the Company in June 2017 ("Fixed-Rate Promissory Note") related to and secured by two office buildings owned by the Company, and non-recourse notes issued by the Company to other banks related to certain capital leases. At September 30, 2017 , the Fixed-Rate Promissory Note had a balance of $49.3 million . Under the Fixed-Rate Promissory Note, the Company will make monthly principal payments and pay interest at a fixed rate of 3.36% until maturity on June 30, 2022 . Under a previous fixed-rate promissory note with an unrelated creditor related to and secured by an office building owned by the Company, other borrowings totaled $17.7 million and $17.8 million at December 31, 2016 and September 30, 2016 , respectively. In June 2017, this previous fixed-rate promissory note was paid off upon the Company's issuance of the Fixed-Rate Promissory Note. At September 30, 2017 , the non-recourse notes related to certain capital leases totaled $225,000 compared to $447,000 and $519,000 at December 31, 2016 and September 30, 2016 , respectively. Secured Borrowings Secured borrowings at September 30, 2017 primarily represents transactions to sell an undivided co-ownership interest in all receivables owed to the Company's subsidiary, FIFC Canada. In December 2014, FIFC Canada sold such interest to an unrelated third party in exchange for a cash payment of approximately C$150 million pursuant to a receivables purchase agreement (“Receivables Purchase Agreement”). The Receivables Purchase Agreement was amended in December 2015, effectively extending the maturity date from December 15, 2015 to December 15, 2017 . Additionally, at that time, the unrelated third party paid an additional C$10 million , which increased the total payments to C$160 million . These transactions were not considered sales of receivables and, as such, related proceeds received are reflected on the Company’s Consolidated Statements of Condition as a secured borrowing owed to the unrelated third party, net of unamortized debt issuance costs, and translated to the Company’s reporting currency as of the respective date. At September 30, 2017 , the translated balance of the secured borrowing totaled $128.3 million compared to $119.0 million at December 31, 2016 and $121.9 million at September 30, 2016 . Additionally, the interest rate under the Receivables Purchase Agreement at September 30, 2017 was 1.9094% . The remaining $12.7 million within secured borrowings at September 30, 2017 represents other sold interests in certain loans by the Company that were not considered sales and, as such, related proceeds received are reflected on the Company’s Consolidated Statements of Condition as a secured borrowing owed to the various unrelated third parties. Subordinated Notes At September 30, 2017 , the Company had outstanding subordinated notes totaling $139.1 million compared to $139.0 million and $138.9 million outstanding at December 31, 2016 and September 30, 2016 , respectively. The notes have a stated interest rate of 5.00% and mature in June 2024 . These notes are stated at par adjusted for unamortized costs paid related to the issuance of this debt.

Junior Subordinated Debentures

Junior Subordinated Debentures	9 Months Ended
	Sep. 30, 2017
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Junior Subordinated Debentures	Junior Subordinated Debentures As of September 30, 2017 , the Company owned 100% of the common securities of eleven trusts, Wintrust Capital Trust III, Wintrust Statutory Trust IV, Wintrust Statutory Trust V, Wintrust Capital Trust VII, Wintrust Capital Trust VIII, Wintrust Capital Trust IX, Northview Capital Trust I, Town Bankshares Capital Trust I, First Northwest Capital Trust I, Suburban Illinois Capital Trust II, and Community Financial Shares Statutory Trust II (the “Trusts”) set up to provide long-term financing. The Northview, Town, First Northwest, Suburban, and Community Financial Shares capital trusts were acquired as part of the acquisitions of Northview Financial Corporation, Town Bankshares, Ltd., First Northwest Bancorp, Inc., Suburban and CFIS, respectively. The Trusts were formed for purposes of issuing trust preferred securities to third-party investors and investing the proceeds from the issuance of the trust preferred securities and common securities solely in junior subordinated debentures issued by the Company (or assumed by the Company in connection with an acquisition), with the same maturities and interest rates as the trust preferred securities. The junior subordinated debentures are the sole assets of the Trusts. In each Trust, the common securities represent approximately 3% of the junior subordinated debentures and the trust preferred securities represent approximately 97% of the junior subordinated debentures. In January 2016, the Company acquired $15.0 million of the $40.0 million of trust preferred securities issued by Wintrust Capital Trust VIII from a third-party investor. The purchase effectively extinguished $15.0 million of junior subordinated debentures related to Wintrust Capital Trust VIII and resulted in a $4.3 million gain from the early extinguishment of debt. The Trusts are reported in the Company’s consolidated financial statements as unconsolidated subsidiaries. Accordingly, in the Consolidated Statements of Condition, the junior subordinated debentures issued by the Company to the Trusts are reported as liabilities and the common securities of the Trusts, all of which are owned by the Company, are included in available-for-sale securities. The following table provides a summary of the Company’s junior subordinated debentures as of September 30, 2017 . The junior subordinated debentures represent the par value of the obligations owed to the Trusts. (Dollars in thousands) Common Securities Trust Preferred Securities Junior Subordinated Debentures Rate Structure Contractual rate at 9/30/2017 Issue Date Maturity Date Earliest Redemption Date Wintrust Capital Trust III $ 774 $ 25,000 $ 25,774 L+3.25 4.55 % 04/2003 04/2033 04/2008 Wintrust Statutory Trust IV 619 20,000 20,619 L+2.80 4.14 % 12/2003 12/2033 12/2008 Wintrust Statutory Trust V 1,238 40,000 41,238 L+2.60 3.94 % 05/2004 05/2034 06/2009 Wintrust Capital Trust VII 1,550 50,000 51,550 L+1.95 3.27 % 12/2004 03/2035 03/2010 Wintrust Capital Trust VIII 1,238 25,000 26,238 L+1.45 2.79 % 08/2005 09/2035 09/2010 Wintrust Capital Trust IX 1,547 50,000 51,547 L+1.63 2.95 % 09/2006 09/2036 09/2011 Northview Capital Trust I 186 6,000 6,186 L+3.00 4.31 % 08/2003 11/2033 08/2008 Town Bankshares Capital Trust I 186 6,000 6,186 L+3.00 4.31 % 08/2003 11/2033 08/2008 First Northwest Capital Trust I 155 5,000 5,155 L+3.00 4.34 % 05/2004 05/2034 05/2009 Suburban Illinois Capital Trust II 464 15,000 15,464 L+1.75 3.07 % 12/2006 12/2036 12/2011 Community Financial Shares Statutory Trust II 109 3,500 3,609 L+1.62 2.94 % 06/2007 09/2037 06/2012 Total $ 253,566 3.52 % The junior subordinated debentures totaled $253.6 million at September 30, 2017 , December 31, 2016 and September 30, 2016 . The interest rates on the variable rate junior subordinated debentures are based on the three-month LIBOR rate and reset on a quarterly basis. At September 30, 2017 , the weighted average contractual interest rate on the junior subordinated debentures was 3.52% . Distributions on the common and preferred securities issued by the Trusts are payable quarterly at a rate per annum equal to the interest rates being earned by the Trusts on the junior subordinated debentures. Interest expense on the junior subordinated debentures is deductible for income tax purposes. The Company has guaranteed the payment of distributions and payments upon liquidation or redemption of the trust preferred securities, in each case to the extent of funds held by the Trusts. The Company and the Trusts believe that, taken together, the obligations of the Company under the guarantees, the junior subordinated debentures, and other related agreements provide, in the aggregate, a full, irrevocable and unconditional guarantee, on a subordinated basis, of all of the obligations of the Trusts under the trust preferred securities. Subject to certain limitations, the Company has the right to defer the payment of interest on the junior subordinated debentures at any time, or from time to time, for a period not to exceed 20 consecutive quarters. The trust preferred securities are subject to mandatory redemption, in whole or in part, upon repayment of the junior subordinated debentures at maturity or their earlier redemption. The junior subordinated debentures are redeemable in whole or in part prior to maturity at any time after the earliest redemption dates shown in the table, and earlier at the discretion of the Company if certain conditions are met, and, in any event, only after the Company has obtained Federal Reserve Bank ("FRB") approval, if then required under applicable guidelines or regulations. Prior to January 1, 2015, the junior subordinated debentures, subject to certain limitations, qualified as Tier 1 regulatory capital of the Company and the amount in excess of those certain limitations could, subject to other restrictions, be included in Tier 2 capital. Starting in 2015, a portion of these junior subordinated debentures still qualified as Tier 1 regulatory capital of the Company and the amount in excess of those certain limitations, subject to certain restrictions, was included in Tier 2 capital. Starting in 2016, none of the junior subordinated debentures qualified as Tier 1 regulatory capital of the Company resulting in $245.5 million of the junior subordinated debentures, net of common securities, being included in the Company's Tier 2 regulatory capital.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information The Company’s operations consist of three primary segments: community banking, specialty finance and wealth management. The three reportable segments are strategic business units that are separately managed as they offer different products and services and have different marketing strategies. In addition, each segment’s customer base has varying characteristics and each segment has a different regulatory environment. While the Company’s management monitors each of the fifteen bank subsidiaries’ operations and profitability separately, these subsidiaries have been aggregated into one reportable operating segment due to the similarities in products and services, customer base, operations, profitability measures, and economic characteristics. For purposes of internal segment profitability, management allocates certain intersegment and parent company balances. Management allocates a portion of revenues to the specialty finance segment related to loans and leases originated by the specialty finance segment and sold or assigned to the community banking segment. Similarly, for purposes of analyzing the contribution from the wealth management segment, management allocates a portion of the net interest income earned by the community banking segment on deposit balances of customers of the wealth management segment to the wealth management segment. See Note 9 — Deposits, for more information on these deposits. Finally, expenses incurred at the Wintrust parent company are allocated to each segment based on each segment's risk-weighted assets. The segment financial information provided in the following tables has been derived from the internal profitability reporting system used by management to monitor and manage the financial performance of the Company. The accounting policies of the segments are substantially similar to those described in “Summary of Significant Accounting Policies” in Note 1 of the Company’s 2016 Form 10-K. The Company evaluates segment performance based on after-tax profit or loss and other appropriate profitability measures common to each segment. The following is a summary of certain operating information for reportable segments: Three months ended $ Change in Contribution % Change in Contribution (Dollars in thousands) September 30, September 30, Net interest income: Community Banking $ 176,526 $ 150,159 $ 26,367 18 % Specialty Finance 30,501 25,543 4,958 19 Wealth Management 4,557 4,835 (278 ) (6 ) Total Operating Segments 211,584 180,537 31,047 17 Intersegment Eliminations 4,404 4,099 305 7 Consolidated net interest income $ 215,988 $ 184,636 $ 31,352 17 % Non-interest income: Community Banking $ 52,554 $ 62,730 $ (10,176 ) (16 )% Specialty Finance 16,315 12,226 4,089 33 Wealth Management 20,371 20,045 326 2 Total Operating Segments 89,240 95,001 (5,761 ) (6 ) Intersegment Eliminations (9,509 ) (8,397 ) (1,112 ) (13 ) Consolidated non-interest income $ 79,731 $ 86,604 $ (6,873 ) (8 )% Net revenue: Community Banking $ 229,080 $ 212,889 $ 16,191 8 % Specialty Finance 46,816 37,769 9,047 24 Wealth Management 24,928 24,880 48 — Total Operating Segments 300,824 275,538 25,286 9 Intersegment Eliminations (5,105 ) (4,298 ) (807 ) (19 ) Consolidated net revenue $ 295,719 $ 271,240 $ 24,479 9 % Segment profit: Community Banking $ 44,799 $ 37,527 $ 7,272 19 % Specialty Finance 17,043 12,767 4,276 33 Wealth Management 3,784 2,821 963 34 Consolidated net income $ 65,626 $ 53,115 $ 12,511 24 % Segment assets: Community Banking $ 22,426,049 $ 21,019,002 $ 1,407,047 7 % Specialty Finance 4,305,960 3,702,241 603,719 16 Wealth Management 626,153 600,516 25,637 4 Consolidated total assets $ 27,358,162 $ 25,321,759 $ 2,036,403 8 % Nine months ended $ Change in Contribution % Change in Contribution (Dollars in thousands) September 30, September 30, Net interest income: Community Banking $ 499,135 $ 434,108 $ 65,027 15 % Specialty Finance 85,871 71,075 14,796 21 Wealth Management 14,532 13,701 831 6 Total Operating Segments 599,538 518,884 80,654 16 Intersegment Eliminations 13,439 12,531 908 7 Consolidated net interest income $ 612,977 $ 531,415 $ 81,562 15 % Non-interest income: Community Banking $ 160,277 $ 169,210 $ (8,933 ) (5 )% Specialty Finance 44,192 37,111 7,081 19 Wealth Management 61,746 58,660 3,086 5 Total Operating Segments 266,215 264,981 1,234 — Intersegment Eliminations (27,747 ) (24,826 ) (2,921 ) (12 ) Consolidated non-interest income $ 238,468 $ 240,155 $ (1,687 ) (1 )% Net revenue: Community Banking $ 659,412 $ 603,318 $ 56,094 9 % Specialty Finance 130,063 108,186 21,877 20 Wealth Management 76,278 72,361 3,917 5 Total Operating Segments 865,753 783,865 81,888 10 Intersegment Eliminations (14,308 ) (12,295 ) (2,013 ) (16 ) Consolidated net revenue $ 851,445 $ 771,570 $ 79,875 10 % Segment profit: Community Banking $ 128,502 $ 106,860 $ 21,642 20 % Specialty Finance 47,990 36,283 11,707 32 Wealth Management 12,409 9,124 3,285 36 Consolidated net income $ 188,901 $ 152,267 $ 36,634 24 %

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company primarily enters into derivative financial instruments as part of its strategy to manage its exposure to changes in interest rates. Derivative instruments represent contracts between parties that result in one party delivering cash to the other party based on a notional amount and an underlying term (such as a rate, security price or price index) as specified in the contract. The amount of cash delivered from one party to the other is determined based on the interaction of the notional amount of the contract with the underlying term. Derivatives are also implicit in certain contracts and commitments. The derivative financial instruments currently used by the Company to manage its exposure to interest rate risk include: (1) interest rate swaps and caps to manage the interest rate risk of certain fixed and variable rate assets and variable rate liabilities; (2) interest rate lock commitments provided to customers to fund certain mortgage loans to be sold into the secondary market; (3) forward commitments for the future delivery of such mortgage loans to protect the Company from adverse changes in interest rates and corresponding changes in the value of mortgage loans held-for-sale; and (4) covered call options to economically hedge specific investment securities and receive fee income effectively enhancing the overall yield on such securities to compensate for net interest margin compression. The Company also enters into derivatives (typically interest rate swaps) with certain qualified borrowers to facilitate the borrowers’ risk management strategies and concurrently enters into mirror-image derivatives with a third party counterparty, effectively making a market in the derivatives for such borrowers. Additionally, the Company enters into foreign currency contracts to manage foreign exchange risk associated with certain foreign currency denominated assets. The Company recognizes derivative financial instruments in the consolidated financial statements at fair value regardless of the purpose or intent for holding the instrument. The Company records derivative assets and derivative liabilities on the Consolidated Statements of Condition within accrued interest receivable and other assets and accrued interest payable and other liabilities, respectively. Changes in the fair value of derivative financial instruments are either recognized in income or in shareholders’ equity as a component of other comprehensive income depending on whether the derivative financial instrument qualifies for hedge accounting and, if so, whether it qualifies as a fair value hedge or cash flow hedge. Generally, changes in fair values of derivatives accounted for as fair value hedges are recorded in income in the same period and in the same income statement line as changes in the fair values of the hedged items that relate to the hedged risk(s). Changes in fair values of derivative financial instruments accounted for as cash flow hedges, to the extent they are effective hedges, are recorded as a component of other comprehensive income, net of deferred taxes, and reclassified to earnings when the hedged transaction affects earnings. Changes in fair values of derivative financial instruments not designated in a hedging relationship pursuant to ASC 815, including changes in fair value related to the ineffective portion of cash flow hedges, are reported in non-interest income during the period of the change. Derivative financial instruments are valued by a third party and are corroborated by comparison with valuations provided by the respective counterparties. Fair values of certain mortgage banking derivatives (interest rate lock commitments and forward commitments to sell mortgage loans) are estimated based on changes in mortgage interest rates from the date of the loan commitment. The fair value of foreign currency derivatives is computed based on changes in foreign currency rates stated in the contract compared to those prevailing at the measurement date. The table below presents the fair value of the Company’s derivative financial instruments as of September 30, 2017 , December 31, 2016 and September 30, 2016 : Derivative Assets Derivative Liabilities (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, Derivatives designated as hedging instruments under ASC 815: Interest rate derivatives designated as Cash Flow Hedges $ 8,643 $ 8,011 $ 549 $ — $ — $ 7 Interest rate derivatives designated as Fair Value Hedges 2,036 2,228 177 53 — 907 Total derivatives designated as hedging instruments under ASC 815 $ 10,679 $ 10,239 $ 726 $ 53 $ — $ 914 Derivatives not designated as hedging instruments under ASC 815: Interest rate derivatives $ 34,489 $ 38,974 $ 79,477 $ 33,982 $ 37,665 $ 79,199 Interest rate lock commitments 2,851 4,265 8,352 1 1,325 4,060 Forward commitments to sell mortgage loans 19 2,037 — 1,495 — 3,505 Foreign exchange contracts 160 879 273 242 849 270 Total derivatives not designated as hedging instruments under ASC 815 $ 37,519 $ 46,155 $ 88,102 $ 35,720 $ 39,839 $ 87,034 Total Derivatives $ 48,198 $ 56,394 $ 88,828 $ 35,773 $ 39,839 $ 87,948 Cash Flow Hedges of Interest Rate Risk The Company’s objectives in using interest rate derivatives are to add stability to net interest income and to manage its exposure to interest rate movements. To accomplish these objectives, the Company primarily uses interest rate swaps and interest rate caps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without the exchange of the underlying notional amount. Interest rate caps designated as cash flow hedges involve the receipt of payments at the end of each period in which the interest rate specified in the contract exceeds the agreed upon strike price. As of September 30, 2017 , the Company had four interest rate swap derivatives designated as cash flow hedges of variable rate deposits. The interest rate swap derivatives had notional amounts of $200.0 million , $250.0 million , $275.0 million and $200.0 million and mature in June 2019, July 2019, August 2019 and June 2020, respectively. The effective portion of changes in the fair value of these cash flow hedges is recorded in accumulated other comprehensive income and is subsequently reclassified to interest expense as interest payments are made on the Company’s variable rate junior subordinated debentures. The changes in fair value (net of tax) are separately disclosed in the Consolidated Statements of Comprehensive Income. The ineffective portion of the change in fair value of these derivatives is recognized directly in earnings; however, no hedge ineffectiveness was recognized during the nine months ended September 30, 2017 or September 30, 2016 . The Company uses the hypothetical derivative method to assess and measure hedge effectiveness. The table below provides details on each of these cash flow hedges as of September 30, 2017 : September 30, 2017 (Dollars in thousands) Notional Fair Value Maturity Date Amount Asset (Liability) Interest Rate Swaps: June 2019 $ 200,000 $ 295 July 2019 250,000 3,549 August 2019 275,000 4,434 June 2020 200,000 365 Total Cash Flow Hedges $ 925,000 $ 8,643 A rollforward of the amounts in accumulated other comprehensive loss related to interest rate derivatives designated as cash flow hedges follows: Three months ended Nine months ended (Dollars in thousands) September 30, September 30, September 30, September 30, Unrealized gain (loss) at beginning of period $ 8,249 $ (3,574 ) $ 6,944 $ (3,529 ) Amount reclassified from accumulated other comprehensive loss to interest expense on deposits and junior subordinated debentures 14 1,065 1,051 2,620 Amount of (loss) gain recognized in other comprehensive income 380 1,708 648 108 Unrealized gain (loss) at end of period $ 8,643 $ (801 ) $ 8,643 $ (801 ) As of September 30, 2017 , the Company estimates that during the next twelve months, $3.5 million will be reclassified from accumulated other comprehensive gain as an increase to interest expense. Fair Value Hedges of Interest Rate Risk Interest rate swaps designated as fair value hedges involve the payment of fixed amounts to a counterparty in exchange for the Company receiving variable payments over the life of the agreements without the exchange of the underlying notional amount. As of September 30, 2017 , the Company has eleven interest rate swaps with an aggregate notional amount of $126.1 million that were designated as fair value hedges associated with fixed rate commercial and industrial and commercial franchise loans as well as life insurance premium finance receivables. For derivatives designated and that qualify as fair value hedges, the gain or loss on the derivative as well as the offsetting loss or gain on the hedged item attributable to the hedged risk are recognized in earnings. The Company includes the gain or loss on the hedged item in the same line item as the offsetting loss or gain on the related derivatives. The Company recognized a net gain of $12,000 and $35,000 in other income related to hedge ineffectiveness for the three months ended September 30, 2017 and 2016 , respectively. On a year-to-date basis, the Company recognized a net gain of $41,000 and a net gain of $13,000 in other income related to hedge ineffectiveness for the nine months ended September 30, 2017 and 2016 , respectively. The following table presents the gain/(loss) and hedge ineffectiveness recognized on derivative instruments and the related hedged items that are designated as a fair value hedge accounting relationship as of September 30, 2017 and 2016 : (Dollars in thousands) Derivatives in Fair Value Location of Gain/(Loss) Amount of (Loss)/Gain Recognized Three Months Ended Amount of Gain/(Loss) Recognized Three Months Ended Income Statement Gain Three Months Ended September 30, September 30, September 30, September 30, September 30, September 30, Interest rate swaps Trading losses, net $ (64 ) $ 269 $ 76 $ (234 ) $ 12 $ 35 (Dollars in thousands) Derivatives in Fair Value Hedging Relationships Location of Gain/(Loss) Recognized in Income on Derivative Amount of Loss Recognized in Income on Derivative Nine Months Ended Amount of Gain Recognized in Income on Hedged Item Nine Months Ended Income Statement Gain due to Hedge Ineffectiveness Nine Months Ended September 30, September 30, September 30, September 30, September 30, September 30, Interest rate swaps Trading losses, net $ (245 ) $ (614 ) $ 286 $ 627 $ 41 $ 13 Non-Designated Hedges The Company does not use derivatives for speculative purposes. Derivatives not designated as accounting hedges are used to manage the Company’s economic exposure to interest rate movements and other identified risks but do not meet the strict hedge accounting requirements of ASC 815. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings. Interest Rate Derivatives —The Company has interest rate derivatives, including swaps and option products, resulting from a service the Company provides to certain qualified borrowers. The Company’s banking subsidiaries execute certain derivative products (typically interest rate swaps) directly with qualified commercial borrowers to facilitate their respective risk management strategies. For example, these arrangements allow the Company’s commercial borrowers to effectively convert a variable rate loan to a fixed rate. In order to minimize the Company’s exposure on these transactions, the Company simultaneously executes offsetting derivatives with third parties. In most cases, the offsetting derivatives have mirror-image terms, which result in the positions’ changes in fair value substantially offsetting through earnings each period. However, to the extent that the derivatives are not a mirror-image and because of differences in counterparty credit risk, changes in fair value will not completely offset resulting in some earnings impact each period. Changes in the fair value of these derivatives are included in non-interest income. At September 30, 2017 , the Company had interest rate derivative transactions with an aggregate notional amount of approximately $4.9 billion (all interest rate swaps and caps with customers and third parties) related to this program. These interest rate derivatives had maturity dates ranging from October 2017 to February 2045 . Mortgage Banking Derivatives— These derivatives include interest rate lock commitments provided to customers to fund certain mortgage loans to be sold into the secondary market and forward commitments for the future delivery of such loans. It is the Company’s practice to enter into forward commitments for the future delivery of a portion of our residential mortgage loan production when interest rate lock commitments are entered into in order to economically hedge the effect of future changes in interest rates on its commitments to fund the loans as well as on its portfolio of mortgage loans held-for-sale. The Company’s mortgage banking derivatives have not been designated as being in hedge relationships. At September 30, 2017 , the Company had forward commitments to sell mortgage loans with an aggregate notional amount of approximately $773.5 million and interest rate lock commitments with an aggregate notional amount of approximately $409.3 million . The fair values of these derivatives were estimated based on changes in mortgage rates from the dates of the commitments. Changes in the fair value of these mortgage banking derivatives are included in mortgage banking revenue. Foreign Currency Derivatives— These derivatives include foreign currency contracts used to manage the foreign exchange risk associated with foreign currency denominated assets and transactions. Foreign currency contracts, which include spot and forward contracts, represent agreements to exchange the currency of one country for the currency of another country at an agreed-upon price on an agreed-upon settlement date. As a result of fluctuations in foreign currencies, the U.S. dollar-equivalent value of the foreign currency denominated assets or forecasted transactions increase or decrease. Gains or losses on the derivative instruments related to these foreign currency denominated assets or forecasted transactions are expected to substantially offset this variability. As of September 30, 2017 the Company held foreign currency derivatives with an aggregate notional amount of approximately $43.4 million . Other Derivatives— Periodically, the Company will sell options to a bank or dealer for the right to purchase certain securities held within the banks’ investment portfolios (covered call options). These option transactions are designed primarily to mitigate overall interest rate risk and to increase the total return associated with the investment securities portfolio. These options do not qualify as accounting hedges pursuant to ASC 815, and, accordingly, changes in fair value of these contracts are recognized as other non-interest income. There were no covered call options outstanding as of September 30, 2017 , December 31, 2016 or September 30, 2016 . Amounts included in the Consolidated Statements of Income related to derivative instruments not designated in hedge relationships were as follows: (Dollars in thousands) Three Months Ended Nine Months Ended Derivative Location in income statement September 30, September 30, September 30, September 30, Interest rate swaps and caps Trading losses, net $ (94 ) $ (395 ) $ (762 ) $ (751 ) Mortgage banking derivatives Mortgage banking revenue 708 (2,215 ) 1,398 (3,058 ) Covered call options Fees from covered call options 1,143 3,633 2,792 9,994 Foreign exchange contracts Trading losses, net (23 ) (26 ) (115 ) (262 ) Credit Risk Derivative instruments have inherent risks, primarily market risk and credit risk. Market risk is associated with changes in interest rates and credit risk relates to the risk that the counterparty will fail to perform according to the terms of the agreement. The amounts potentially subject to market and credit risks are the streams of interest payments under the contracts and the market value of the derivative instrument and not the notional principal amounts used to express the volume of the transactions. Market and credit risks are managed and monitored as part of the Company's overall asset-liability management process, except that the credit risk related to derivatives entered into with certain qualified borrowers is managed through the Company's standard loan underwriting process since these derivatives are secured through collateral provided by the loan agreements. Actual exposures are monitored against various types of credit limits established to contain risk within parameters. When deemed necessary, appropriate types and amounts of collateral are obtained to minimize credit exposure. The Company has agreements with certain of its interest rate derivative counterparties that contain cross-default provisions, which provide that if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. The Company also has agreements with certain of its derivative counterparties that contain a provision allowing the counterparty to terminate the derivative positions if the Company fails to maintain its status as a well or adequately capitalized institution, which would require the Company to settle its obligations under the agreements. As of September 30, 2017 , the fair value of interest rate derivatives in a net liability position that were subject to such agreements, which includes accrued interest related to these agreements, was $9.8 million . If the Company had breached any of these provisions and the derivatives were terminated as a result, the Company would have been required to settle its obligations under the agreements at the termination value and would have been required to pay any additional amounts due in excess of amounts previously posted as collateral with the respective counterparty. The Company is also exposed to the credit risk of its commercial borrowers who are counterparties to interest rate derivatives with the banks. This counterparty risk related to the commercial borrowers is managed and monitored through the banks' standard underwriting process applicable to loans since these derivatives are secured through collateral provided by the loan agreement. The counterparty risk associated with the mirror-image swaps executed with third parties is monitored and managed in connection with the Company's overall asset liability management process. The Company records interest rate derivatives subject to master netting agreements at their gross value and does not offset derivative assets and liabilities on the Consolidated Statements of Condition. The tables below summarize the Company's interest rate derivatives and offsetting positions as of the dates shown. Derivative Assets Derivative Liabilities Fair Value Fair Value (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, Gross Amounts Recognized $ 45,168 $ 49,213 $ 80,203 $ 34,035 $ 37,665 $ 80,113 Less: Amounts offset in the Statements of Financial Condition — — — — — — Net amount presented in the Statements of Financial Condition $ 45,168 $ 49,213 $ 80,203 $ 34,035 $ 37,665 $ 80,113 Gross amounts not offset in the Statements of Financial Condition Offsetting Derivative Positions $ (16,213 ) (14,441 ) (958 ) $ (16,213 ) (14,441 ) (958 ) Collateral Posted (1) (2,950 ) (8,530 ) — (17,130 ) (12,400 ) (79,155 ) Net Credit Exposure $ 26,005 $ 26,242 $ 79,245 $ 692 $ 10,824 $ — (1) As of September 30, 2016, the Company posted collateral of $86.0 million , which resulted in excess collateral with its counterparties. For purposes of this disclosure, the amount of posted collateral is limited to the amount offsetting the derivative liability.

Fair Values of Assets and Liabi

Fair Values of Assets and Liabilities	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Values of Assets and Liabilities	Fair Values of Assets and Liabilities The Company measures, monitors and discloses certain of its assets and liabilities on a fair value basis. These financial assets and financial liabilities are measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the observability of the assumptions used to determine fair value. These levels are: • Level 1—unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2 — inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3—significant unobservable inputs that reflect the Company’s own assumptions that market participants would use in pricing the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. A financial instrument’s categorization within the above valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the assets or liabilities. Following is a description of the valuation methodologies used for the Company’s assets and liabilities measured at fair value on a recurring basis. Available-for-sale and trading account securities —Fair values for available-for-sale and trading securities are typically based on prices obtained from independent pricing vendors. Securities measured with these valuation techniques are generally classified as Level 2 of the fair value hierarchy. Typically, standard inputs such as benchmark yields, reported trades for similar securities, issuer spreads, benchmark securities, bids, offers and reference data including market research publications are used to fair value a security. When these inputs are not available, broker/dealer quotes may be obtained by the vendor to determine the fair value of the security. We review the vendor’s pricing methodologies to determine if observable market information is being used, versus unobservable inputs. Fair value measurements using significant inputs that are unobservable in the market due to limited activity or a less liquid market are classified as Level 3 in the fair value hierarchy. The Company’s Investment Operations Department is responsible for the valuation of Level 3 available-for-sale securities. The methodology and variables used as inputs in pricing Level 3 securities are derived from a combination of observable and unobservable inputs. The unobservable inputs are determined through internal assumptions that may vary from period to period due to external factors, such as market movement and credit rating adjustments. At September 30, 2017 , the Company classified $68.4 million of municipal securities as Level 3. These municipal securities are bond issues for various municipal government entities primarily located in the Chicago metropolitan area and southern Wisconsin and are privately placed, non-rated bonds without CUSIP numbers. The Company also classified $3.9 million of U.S. government agencies as Level 3 at September 30, 2017 . The Company’s methodology for pricing these securities focuses on three distinct inputs: equivalent rating, yield and other pricing terms. To determine the rating for a given non-rated municipal bond, the Investment Operations Department references a publicly issued bond by the same issuer if available. A reduction is then applied to the rating obtained from the comparable bond, as the Company believes if liquidated, a non-rated bond would be valued less than a similar bond with a verifiable rating. The reduction applied by the Company is one complete rating grade (i.e. a “AA” rating for a comparable bond would be reduced to “A” for the Company’s valuation). In the third quarter of 2017 , all of the ratings derived in the above process by Investment Operations were BBB or better, for both bonds with and without comparable bond proxies. The fair value measurement of municipal bonds is sensitive to the rating input, as a higher rating typically results in an increased valuation. The remaining pricing inputs used in the bond valuation are observable. Based on the rating determined in the above process, Investment Operations obtains a corresponding current market yield curve available to market participants. Other terms including coupon, maturity date, redemption price, number of coupon payments per year, and accrual method are obtained from the individual bond term sheets. Certain municipal bonds held by the Company at September 30, 2017 have a call date that has passed, and are now continuously callable. When valuing these bonds, the fair value is capped at par value as the Company assumes a market participant would not pay more than par for a continuously callable bond. To determine the rating for the U.S. government agency securities, the Investment Operations Department assigned a AAA rating as it is guaranteed by the U.S. government. At September 30, 2017 , December 31, 2016 and September 30, 2016 , the Company held no equity securities classified as Level 3. In prior periods, equity securities in Level 3 were primarily comprised of auction rate preferred securities. The Company’s valuation methodology at that time included modeling the contractual cash flows of the underlying preferred securities and applying a discount to these cash flows by a market spread derived from the market price of the securities underlying debt. In the third quarter of 2016, the Company exchanged these auction rate securities for the underlying preferred securities, resulting in a $2.4 million gain on the nonmonetary sale. The Company classified the preferred securities received as Level 2 in the fair value hierarchy at the time of the transaction due to observable inputs other than quoted prices existing for the preferred securities. Mortgage loans held-for-sale —The fair value of mortgage loans held-for-sale is determined by reference to investor price sheets for loan products with similar characteristics. Loans held-for-investment —The fair value for loans in which the Company elected the fair value option is estimated by discounting future scheduled cash flows for the specific loan through maturity, adjusted for estimated credit losses and prepayments. At September 30, 2017 , the Company classified $29.7 million of loans held-for-investment as Level 3. The weighted average discount rate used as an input to value these loans at September 30, 2017 was 3.65% with discount rates applied ranging from 3% - 4% . The higher the rate utilized to discount estimated future cash flows, the lower the fair value measurement. As noted above, the fair value estimate also includes assumptions of prepayment speeds and credit losses. The Company included a prepayments speed assumption of 9.62% at September 30, 2017 . Prepayment speeds are inversely related to the fair value of these loans as an increase in prepayment speeds results in a decreased valuation. Additionally, the weighted average credit loss rate used as an input to value the specific loans was 0.94% with credit loss rates ranging from 0% - 3% at September 30, 2017 . Mortgage servicing rights ("MSRs") —Fair value for MSRs is determined utilizing a valuation model which calculates the fair value of each servicing rights based on the present value of estimated future cash flows. The Company uses a discount rate commensurate with the risk associated with each servicing rights, given current market conditions. At September 30, 2017 , the Company classified $29.4 million of MSRs as Level 3. The weighted average discount rate used as an input to value the MSRs at September 30, 2017 was 9.97% with discount rates applied ranging from 9% - 15% . The higher the rate utilized to discount estimated future cash flows, the lower the fair value measurement. The fair value of MSRs was also estimated based on other assumptions including prepayment speeds and the cost to service. Prepayment speeds used as an input to value the MSRs at September 30, 2017 ranged from 0% - 47% or a weighted average prepayment speed of 10.50% . Further, for current and delinquent loans, the Company assumed a weighted average cost of servicing of $69 and $634 , respectively, per loan. Prepayment speeds and the cost to service are both inversely related to the fair value of MSRs as an increase in prepayment speeds or the cost to service results in a decreased valuation. Derivative instruments —The Company’s derivative instruments include interest rate swaps and caps, commitments to fund mortgages for sale into the secondary market (interest rate locks), forward commitments to end investors for the sale of mortgage loans and foreign currency contracts. Interest rate swaps and caps are valued by a third party, using models that primarily use market observable inputs, such as yield curves, and are corroborated by comparison with valuations provided by the respective counterparties. The credit risk associated with derivative financial instruments that are subject to master netting agreements is measured on a net basis by counterparty portfolio. The fair value for mortgage-related derivatives is based on changes in mortgage rates from the date of the commitments. The fair value of foreign currency derivatives is computed based on change in foreign currency rates stated in the contract compared to those prevailing at the measurement date. At September 30, 2017 , the Company classified $1.2 million of derivative assets related to interest rate locks as Level 3. The fair value of interest rate locks is based on prices obtained for loans with similar characteristics from third parties, adjusted for the pull-through rate, which represents the Company’s best estimate of the likelihood that a committed loan will ultimately fund. The weighted-average pull-through rate at September 30, 2017 was 88.85% with pull-through rates applied ranging from 38% to 100% . Pull-through rates are directly related to the fair value of interest rate locks as an increase in the pull-through rate results in an increased valuation Nonqualified deferred compensation assets —The underlying assets relating to the nonqualified deferred compensation plan are included in a trust and primarily consist of non-exchange traded institutional funds which are priced based by an independent third party service. The following tables present the balances of assets and liabilities measured at fair value on a recurring basis for the periods presented: September 30, 2017 (Dollars in thousands) Total Level 1 Level 2 Level 3 Available-for-sale securities U.S. Treasury $ 144,145 $ — $ 144,145 $ — U.S. Government agencies 159,328 — 155,385 3,943 Municipal 116,016 — 47,633 68,383 Corporate notes 60,614 — 60,614 — Mortgage-backed 1,149,448 — 1,149,448 — Equity securities 36,352 — 36,352 — Trading account securities 643 — 643 — Mortgage loans held-for-sale 370,282 — 370,282 — Loans held-for-investment 29,704 — — 29,704 MSRs 29,414 — — 29,414 Nonqualified deferred compensation assets 10,824 — 10,824 — Derivative assets 48,198 — 46,982 1,216 Total $ 2,154,968 $ — $ 2,022,308 $ 132,660 Derivative liabilities $ 35,773 $ — $ 35,773 $ — December 31, 2016 (Dollars in thousands) Total Level 1 Level 2 Level 3 Available-for-sale securities U.S. Treasury $ 141,983 $ — $ 141,983 $ — U.S. Government agencies 189,152 — 189,152 — Municipal 131,809 — 52,183 79,626 Corporate notes 65,391 — 65,391 — Mortgage-backed 1,161,084 — 1,161,084 — Equity securities 35,248 — 35,248 — Trading account securities 1,989 — 1,989 — Mortgage loans held-for-sale 418,374 — 418,374 — Loans held-for-investment 22,137 — — 22,137 MSRs 19,103 — — 19,103 Nonqualified deferred compensation assets 9,228 — 9,228 — Derivative assets 56,394 — 54,103 2,291 Total $ 2,251,892 $ — $ 2,128,735 $ 123,157 Derivative liabilities $ 39,839 $ — $ 39,839 $ — September 30, 2016 (Dollars in thousands) Total Level 1 Level 2 Level 3 Available-for-sale securities U.S. Treasury $ 30,036 $ — $ 30,036 $ — U.S. Government agencies 93,683 — 93,683 — Municipal 109,281 — 42,073 67,208 Corporate notes 65,203 — 65,203 — Mortgage-backed 1,301,111 — 1,301,111 — Equity securities 50,782 — 50,782 — Trading account securities 1,092 — 1,092 — Mortgage loans held-for-sale 559,634 — 559,634 — Loans held-for-investment 17,603 — 17,603 — MSRs 13,901 — — 13,901 Nonqualified deferred compensation assets 9,218 — 9,218 — Derivative assets 88,828 — 82,791 6,037 Total $ 2,340,372 $ — $ 2,253,226 $ 87,146 Derivative liabilities $ 87,948 $ — $ 87,948 $ — The aggregate remaining contractual principal balance outstanding as of September 30, 2017 , December 31, 2016 and September 30, 2016 for mortgage loans held-for-sale measured at fair value under ASC 825 was $356.4 million , $414.4 million and $537.0 million , respectively, while the aggregate fair value of mortgage loans held-for-sale was $370.3 million , $418.4 million and $559.6 million , for the same respective periods, as shown in the above tables. There were no nonaccrual loans or loans past due greater than 90 days and still accruing in the mortgage loans held-for-sale portfolio as of September 30, 2017 , December 31, 2016 and September 30, 2016 . The changes in Level 3 assets measured at fair value on a recurring basis during the three and nine months ended September 30, 2017 and 2016 are summarized as follows: Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at July 1, 2017 $ 77,341 $ — $ 4,110 $ 30,173 $ 27,307 $ 1,047 Total net gains (losses) included in: Net income (1) — — — 177 2,107 169 Other comprehensive loss (4,113 ) — (167 ) — — — Purchases — — — — — — Issuances — — — — — — Sales — — — — — — Settlements (4,845 ) — — (4,504 ) — — Net transfers into/(out of) Level 3 — — — 3,858 — — Balance at September 30, 2017 $ 68,383 $ — $ 3,943 $ 29,704 $ 29,414 $ 1,216 (1) Changes in the balance of MSRs are recorded as a component of mortgage banking revenue in non-interest income. Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at January 1, 2017 $ 79,626 $ — $ — $ 22,137 $ 19,103 $ 2,291 Total net gains (losses) included in: Net income (1) — — — 1,369 10,311 (1,075 ) Other comprehensive loss (1,084 ) — (340 ) — — — Purchases 10,879 — — — — — Issuances — — — — — — Sales — — — — — — Settlements (21,038 ) — — (9,995 ) — — Net transfers into/(out of) Level 3 — — 4,283 16,193 — — Balance at September 30, 2017 $ 68,383 $ — $ 3,943 $ 29,704 $ 29,414 $ 1,216 Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at July 1, 2016 $ 69,812 $ 25,187 $ — $ — $ 13,382 $ 9,731 Total net gains (losses) included in: Net income (1) — — — — 519 (3,694 ) Other comprehensive loss (241 ) — — — — Purchases 2,184 — — — — — Issuances — — — — — — Sales — (25,187 ) — — — — Settlements (4,547 ) — — — — — Net transfers into/(out of) Level 3 — — — — — — Balance at September 30, 2016 $ 67,208 $ — $ — $ — $ 13,901 $ 6,037 Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at January 1, 2016 $ 68,613 $ 25,199 $ — $ — $ 9,092 $ 7,021 Total net gains (losses) included in: Net income (1) — — — — 4,809 (984 ) Other comprehensive loss (141 ) (12 ) — — — — Purchases 6,458 — — — — — Issuances — — — — — — Sales — (25,187 ) — — — — Settlements (7,722 ) — — — — — Net transfers into/(out of) Level 3 — — — — — — Balance at September 30, 2016 $ 67,208 $ — $ — $ — $ 13,901 $ 6,037 (1) Changes in the balance of MSRs are recorded as a component of mortgage banking revenue in non-interest income. Also, the Company may be required, from time to time, to measure certain other financial assets at fair value on a nonrecurring basis in accordance with GAAP. These adjustments to fair value usually result from impairment charges on individual assets. For assets measured at fair value on a nonrecurring basis that were still held in the balance sheet at the end of the period, the following table provides the carrying value of the related individual assets or portfolios at September 30, 2017 . September 30, 2017 Three Months Ended September 30, 2017 Fair Value Losses Recognized, net Nine Months Ended September 30, 2017 Fair Value Losses Recognized, net (Dollars in thousands) Total Level 1 Level 2 Level 3 Impaired loans—collateral based $ 57,548 $ — $ — $ 57,548 $ 4,259 $ 10,589 Other real estate owned, including covered other real estate owned (1) 40,229 — — 40,229 490 1,760 Total $ 97,777 $ — $ — $ 97,777 $ 4,749 $ 12,349 (1) Fair value losses recognized, net on other real estate owned include valuation adjustments and charge-offs during the respective period. Impaired loans —A loan is considered to be impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due pursuant to the contractual terms of the loan agreement. A loan modified in a TDR is an impaired loan according to applicable accounting guidance. Impairment is measured by estimating the fair value of the loan based on the present value of expected cash flows, the market price of the loan, or the fair value of the underlying collateral. Impaired loans are considered a fair value measurement where an allowance is established based on the fair value of collateral. Appraised values, which may require adjustments to market-based valuation inputs, are generally used on real estate collateral-dependent impaired loans. The Company’s Managed Assets Division is primarily responsible for the valuation of Level 3 inputs of impaired loans. For more information on the Managed Assets Division review of impaired loans refer to Note 7 – Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans. At September 30, 2017 , the Company had $78.6 million of impaired loans classified as Level 3. Of the $78.6 million of impaired loans, $57.5 million were measured at fair value based on the underlying collateral of the loan as shown in the table above. The remaining $21.1 million were valued based on discounted cash flows in accordance with ASC 310. Other real estate owned (including covered other real estate owned) —Other real estate owned is comprised of real estate acquired in partial or full satisfaction of loans and is included in other assets. Other real estate owned is recorded at its estimated fair value less estimated selling costs at the date of transfer, with any excess of the related loan balance over the fair value less expected selling costs charged to the allowance for loan losses. Subsequent changes in value are reported as adjustments to the carrying amount and are recorded in other non-interest expense. Gains and losses upon sale, if any, are also charged to other non-interest expense. Fair value is generally based on third party appraisals and internal estimates that are adjusted by a discount representing the estimated cost of sale and is therefore considered a Level 3 valuation. The Company’s Managed Assets Division is primarily responsible for the valuation of Level 3 inputs for non-covered other real estate owned and covered other real estate owned. At September 30, 2017 , the Company had $40.2 million of other real estate owned classified as Level 3. The unobservable input applied to other real estate owned relates to the 10% reduction to the appraisal value representing the estimated cost of sale of the foreclosed property. A higher discount for the estimated cost of sale results in a decreased carrying value. The valuation techniques and significant unobservable inputs used to measure both recurring and non-recurring Level 3 fair value measurements at September 30, 2017 were as follows: (Dollars in thousands) Fair Value Valuation Methodology Significant Unobservable Input Range of Inputs Weighted Average of Inputs Impact to valuation from an increased or higher input value Measured at fair value on a recurring basis: Municipal Securities $ 68,383 Bond pricing Equivalent rating BBB-AA+ N/A Increase U.S. Government agencies 3,943 Bond pricing Equivalent rating AAA AAA Increase Loans held-for-investment 29,704 Discounted cash flows Discount rate 3%-4% 3.65% Decrease Credit loss rate 0%-3% 0.94% Decrease Constant prepayment rate (CPR) 9.62% 9.62% Decrease MSRs 29,414 Discounted cash flows Discount rate 9%-15% 9.97% Decrease Constant prepayment rate (CPR) 0%-47% 10.50% Decrease Cost of servicing $65-$200 $69 Decrease Cost of servicing - delinquent $200-$1,000 $634 Decrease Derivatives 1,216 Discounted cash flows Pull-through rate 38%-100% 88.85% Increase Measured at fair value on a non-recurring basis: Impaired loans—collateral based $ 57,548 Appraisal value Appraisal adjustment - cost of sale 10% 10.00% Decrease Other real estate owned, including covered other real estate owned 40,229 Appraisal value Appraisal adjustment - cost of sale 10% 10.00% Decrease The Company is required under applicable accounting guidance to report the fair value of all financial instruments on the consolidated statements of condition, including those financial instruments carried at cost. The table below presents the carrying amounts and estimated fair values of the Company’s financial instruments as of the dates shown: At September 30, 2017 At December 31, 2016 At September 30, 2016 Carrying Fair Carrying Fair Carrying Fair (Dollars in thousands) Value Value Value Value Value Value Financial Assets: Cash and cash equivalents $ 251,952 $ 251,952 $ 270,045 $ 270,045 $ 246,947 $ 246,947 Interest bearing deposits with banks 1,218,728 1,218,728 980,457 980,457 816,104 816,104 Available-for-sale securities 1,665,903 1,665,903 1,724,667 1,724,667 1,650,096 1,650,096 Held-to-maturity securities 819,340 807,036 635,705 607,602 932,767 942,666 Trading account securities 643 643 1,989 1,989 1,092 1,092 FHLB and FRB stock, at cost 87,192 87,192 133,494 133,494 129,630 129,630 Brokerage customer receivables 23,631 23,631 25,181 25,181 25,511 25,511 Mortgage loans held-for-sale, at fair value 370,282 370,282 418,374 418,374 559,634 559,634 Loans held-for-investment, at fair value 29,704 29,704 22,137 22,137 17,603 17,603 Loans held-for-investment, at amortized cost 20,929,678 21,064,801 19,739,180 20,755,320 19,179,598 20,233,915 MSRs 29,414 29,414 19,103 19,103 13,901 13,901 Nonqualified deferred compensation assets 10,824 10,824 9,228 9,228 9,218 9,218 Derivative assets 48,198 48,198 56,394 56,394 88,828 88,828 Accrued interest receivable and other 225,435 225,435 204,513 204,513 205,725 205,725 Total financial assets $ 25,710,924 $ 25,833,743 $ 24,240,467 $ 25,228,504 $ 23,876,654 $ 24,940,870 Financial Liabilities Non-maturity deposits $ 18,228,388 $ 18,228,388 $ 17,383,729 $ 17,383,729 $ 16,946,178 $ 16,946,178 Deposits with stated maturities 4,666,675 4,608,760 4,274,903 4,263,576 4,201,477 4,200,278 FHLB advances 468,962 454,753 153,831 157,051 419,632 427,103 Other borrowings 251,680 251,680 262,486 262,486 241,366 241,366 Subordinated notes 139,052 145,376 138,971 135,268 138,943 138,715 Junior subordinated debentures 253,566 240,305 253,566 254,384 253,566 254,108 Derivative liabilities 35,773 35,773 39,839 39,839 87,948 87,948 FDIC indemnification liability 15,472 15,472 16,701 16,701 17,945 17,945 Accrued interest payable 9,177 9,177 6,421 6,421 8,007 8,007 Total financial liabilities $ 24,068,745 $ 23,989,684 $ 22,530,447 $ 22,519,455 $ 22,315,062 $ 22,321,648 Not all the financial instruments listed in the table above are subject to the disclosure provisions of ASC Topic 820, as certain assets and liabilities result in their carrying value approximating fair value. These include cash and cash equivalents, interest bearing deposits with banks, brokerage customer receivables, FHLB and FRB stock, FDIC indemnification asset and liability, accrued interest receivable and accrued interest payable and non-maturity deposits. The following methods and assumptions were used by the Company in estimating fair values of financial instruments that were not previously disclosed. Held-to-maturity securities. Held-to-maturity securities include U.S. Government-sponsored agency securities and municipal bonds issued by various municipal government entities primarily located in the Chicago metropolitan area and southern Wisconsin. Fair values for held-to-maturity securities are typically based on prices obtained from independent pricing vendors. In accordance with ASC 820, the Company has categorized held-to-maturity securities as a Level 2 fair value measurement. Loans held-for-investment, at amortized cost. Fair values are estimated for portfolios of loans with similar financial characteristics. Loans are analyzed by type such as commercial, residential real estate, etc. Each category is further segmented by interest rate type (fixed and variable) and term. For variable-rate loans that reprice frequently, estimated fair values are based on carrying values. The fair value of residential loans is based on secondary market sources for securities backed by similar loans, adjusted for differences in loan characteristics. The fair value for other fixed rate loans is estimated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect credit and interest rate risks inherent in the loan. The primary impact of credit risk on the present value of the loan portfolio, however, was assessed through the use of the allowance for loan losses, which is believed to represent the current fair value of probable incurred losses for purposes of the fair value calculation. In accordance with ASC 820, the Company has categorized loans as a Level 3 fair value measurement. Deposits with stated maturities. The fair value of certificates of deposit is based on the discounted value of contractual cash flows. The discount rate is estimated using the rates currently in effect for deposits of similar remaining maturities. In accordance with ASC 820, the Company has categorized deposits with stated maturities as a Level 3 fair value measurement. FHLB advances. The fair value of FHLB advances is obtained from the FHLB which uses a discounted cash flow analysis based on current market rates of similar maturity debt securities to discount cash flows. In accordance with ASC 820, the Company has categorized FHLB advances as a Level 3 fair value measurement. Subordinated notes. The fair value of the subordinated notes is based on a market price obtained from an independent pricing vendor. In accordance with ASC 820, the Company has categorized subordinated notes as a Level 2 fair value measurement. Junior subordinated debentures. The fair value of the junior subordinated debentures is based on the discounted value of contractual cash flows. In accordance with ASC 820, the Company has categorized junior subordinated debentures as a Level 3 fair value measurement.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	9 Months Ended
	Sep. 30, 2017
Share-based Compensation [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans In May 2015, the Company’s shareholders approved the 2015 Stock Incentive Plan (“the 2015 Plan”) which provides for the issuance of up to 5,485,000 shares of common stock. The 2015 Plan replaced the 2007 Stock Incentive Plan (“the 2007 Plan”) which replaced the 1997 Stock Incentive Plan (“the 1997 Plan”). The 2015 Plan, the 2007 Plan and the 1997 Plan are collectively referred to as “the Plans.” The 2015 Plan has substantially similar terms to the 2007 Plan and the 1997 Plan. Outstanding awards under the Plans for which common shares are not issued by reason of cancellation, forfeiture, lapse of such award or settlement of such award in cash, are again available under the 2015 Plan. All grants made after the approval of the 2015 Plan are made pursuant to the 2015 Plan. As of September 30, 2017 , approximately 4.0 million shares were available for future grants assuming the maximum number of shares are issued for the performance awards outstanding. The Plans cover substantially all employees of Wintrust. The Compensation Committee of the Board of Directors administers all stock-based compensation programs and authorizes all awards granted pursuant to the Plans. The Plans permit the grant of incentive stock options, non-qualified stock options, stock appreciation rights, stock awards, restricted share or unit awards, performance awards and other incentive awards valued in whole or in part by reference to the Company’s common stock, all on a stand alone, combination or tandem basis. The Company historically awarded stock-based compensation in the form of time-vested non-qualified stock options and time-vested restricted share unit awards (“restricted shares”). The grants of options provide for the purchase of shares of the Company’s common stock at the fair market value of the stock on the date the options are granted. Stock options under the 2015 Plan and the 2007 Plan generally vest ratably over periods of three to five years and have a maximum term of seven years from the date of grant. Stock options granted under the 1997 Plan provided for a maximum term of 10 years. Restricted shares entitle the holders to receive, at no cost, shares of the Company’s common stock. Restricted shares generally vest over periods of one to five years from the date of grant. Beginning in 2011, the Company has awarded annual grants under the Long-Term Incentive Program (“LTIP”), which is administered under the Plans. The LTIP is designed in part to align the interests of management with the interests of shareholders, foster retention, create a long-term focus based on sustainable results and provide participants with a target long-term incentive opportunity. It is anticipated that LTIP awards will continue to be granted annually. LTIP grants generally consist of a combination of time-vested non-qualified stock options, performance-based stock awards and performance-based cash awards. Performance-based stock and cash awards granted under the LTIP are contingent upon the achievement of pre-established long-term performance goals set in advance by the Compensation Committee over a three -year period starting at the beginning of each calendar year. These performance awards are granted at a target level, and based on the Company’s achievement of the pre-established long-term goals, the actual payouts can range from 0% to a maximum of 150% (for awards granted after 2014) or 200% (for awards granted prior to 2015) of the target award. The awards vest in the quarter after the end of the performance period upon certification of the payout by the Compensation Committee of the Board of Directors. Holders of performance-based stock awards are entitled to receive, at no cost, the shares earned based on the achievement of the pre-established long-term goals. Holders of restricted share awards and performance-based stock awards received under the Plans are not entitled to vote or receive cash dividends (or cash payments equal to the cash dividends) on the underlying common shares until the awards are vested and issued. Shares that are vested but not issuable pursuant to deferred compensation arrangements accrue additional shares based on the value of dividends otherwise paid. Except in limited circumstances, these awards are canceled upon termination of employment without any payment of consideration by the Company. Stock-based compensation is measured as the fair value of an award on the date of grant, and the measured cost is recognized over the period which the recipient is required to provide service in exchange for the award. The fair values of restricted share and performance-based stock awards are determined based on the average of the high and low trading prices on the grant date, and the fair value of stock options is estimated using a Black-Scholes option-pricing model that utilizes the assumptions outlined in the following table. Option-pricing models require the input of highly subjective assumptions and are sensitive to changes in the option's expected life and the price volatility of the underlying stock, which can materially affect the fair value estimate. Options granted since the inception of the LTIP in 2011 were primarily granted as LTIP awards. Expected life of options granted since the inception of the LTIP awards has been based on the safe harbor rule of the SEC Staff Accounting Bulletin No. 107 “Share-Based Payment” as the Company believes historical exercise data may not provide a reasonable basis to estimate the expected term of these options. Expected stock price volatility is based on historical volatility of the Company's common stock, which correlates with the expected life of the options, and the risk-free interest rate is based on comparable U.S. Treasury rates. Management reviews and adjusts the assumptions used to calculate the fair value of an option on a periodic basis to better reflect expected trends. The following table presents the weighted average assumptions used to determine the fair value of options granted in the nine month period ended September 30, 2016 . No options were granted in the nine month period ended September 30, 2017 . Nine Months Ended September 30, 2016 Expected dividend yield 0.9 % Expected volatility 25.2 % Risk-free rate 1.3 % Expected option life (in years) 4.5 Stock based compensation is recognized based upon the number of awards that are ultimately expected to vest, taking into account expected forfeitures. In addition, for performance-based awards, an estimate is made of the number of shares expected to vest as a result of actual performance against the performance criteria in the award to determine the amount of compensation expense to recognize. The estimate is reevaluated periodically and total compensation expense is adjusted for any change in estimate in the current period. Stock-based compensation expense recognized in the Consolidated Statements of Income was $2.4 million in the third quarter of 2017 and $2.0 million in the third quarter of 2016 , and $8.2 million and $6.8 million for the 2017 and 2016 year-to-date periods, respectively. A summary of the Company's stock option activity for the nine months ended September 30, 2017 and September 30, 2016 is presented below: Stock Options Common Shares Weighted Average Strike Price Remaining Contractual Term (1) Intrinsic Value (2) ($000) Outstanding at January 1, 2017 1,698,912 $ 41.50 Granted — — Exercised (499,222 ) 40.57 Forfeited or canceled (16,378 ) 43.07 Outstanding at September 30, 2017 1,183,312 $ 41.87 4.2 $ 43,122 Exercisable at September 30, 2017 640,759 $ 41.58 3.5 $ 23,532 (1) Represents the remaining weighted average contractual life in years. (2) Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company's stock price on the last trading day of the quarter and the option exercise price, multiplied by the number of shares) that would have been received by the option holders if they had exercised their options on the last day of the quarter. Options with exercise prices above the stock price on the last trading day of the quarter are excluded from the calculation of intrinsic value. The intrinsic value will change based on the fair market value of the Company's stock. Stock Options Common Shares Weighted Average Strike Price Remaining Contractual Term (1) Intrinsic Value (2) ($000) Outstanding at January 1, 2016 1,551,734 $ 41.32 Granted 562,166 41.04 Exercised (184,366 ) 37.43 Forfeited or canceled (86,039 ) 48.93 Outstanding at September 30, 2016 1,843,495 $ 41.27 4.8 $ 26,363 Exercisable at September 30, 2016 813,666 $ 39.27 3.5 $ 13,265 (1) Represents the remaining weighted average contractual life in years. (2) Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company's stock price on the last trading day of the quarter and the option exercise price, multiplied by the number of shares) that would have been received by the option holders if they had exercised their options on the last day of the quarter. Options with exercise prices above the stock price on the last trading day of the quarter are excluded from the calculation of intrinsic value. The intrinsic value will change based on the fair market value of the Company's stock. The weighted average grant date fair value per share of options granted during the nine months ended September 30, 2016 was $8.61 . The aggregate intrinsic value of options exercised during the nine months ended September 30, 2017 and September 30, 2016 , was $16.3 million and $2.7 million , respectively. Cash received from option exercises under the Plan for the nine months ended September 30, 2017 and September 30, 2016 were $20.3 million and $6.9 million , respectively. A summary of the Plans' restricted share activity for the nine months ended September 30, 2017 and September 30, 2016 is presented below: Nine months ended September 30, 2017 Nine months ended September 30, 2016 Restricted Shares Common Shares Weighted Average Grant-Date Fair Value Common Shares Weighted Average Grant-Date Fair Value Outstanding at January 1 133,425 $ 49.94 137,593 $ 49.63 Granted 14,249 72.53 15,764 44.72 Vested and issued (10,695 ) 46.03 (10,041 ) 43.78 Forfeited or canceled (2,551 ) 52.26 (598 ) 44.26 Outstanding at September 30 134,428 $ 52.60 142,718 $ 49.52 Vested, but not issuable at September 30 89,563 $ 51.59 88,889 $ 51.44 A summary of the Plans' performance-based stock award activity, based on the target level of the awards, for the nine months ended September 30, 2017 and September 30, 2016 is presented below: Nine months ended September 30, 2017 Nine months ended September 30, 2016 Performance-based Stock Common Weighted Common Weighted Outstanding at January 1 298,180 $ 43.64 276,533 $ 43.01 Granted 145,829 72.60 118,072 41.02 Vested and issued (68,712 ) 46.85 (78,410 ) 37.90 Forfeited (14,164 ) 52.81 (13,229 ) 41.12 Outstanding at September 30 361,133 $ 54.36 302,966 $ 43.64 Vested, but deferred at September 30 13,616 $ 42.66 6,660 $ 37.93 The Company issues new shares to satisfy its obligation to issue shares granted pursuant to the Plans.

Shareholders' Equity and Earnin

Shareholders' Equity and Earnings Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Shareholders' Equity and Earnings Per Share	Shareholders’ Equity and Earnings Per Share Common Stock Offering In June 2016, the Company issued through a public offering a total of 3,000,000 shares of its common stock. Net proceeds to the Company totaled approximately $152.9 million . Series D Preferred Stock In June 2015, the Company issued and sold 5,000,000 shares of fixed-to-floating non-cumulative perpetual preferred stock, Series D, liquidation preference $25 per share (the “Series D Preferred Stock”) for $125.0 million in a public offering. When, as and if declared, dividends on the Series D Preferred Stock are payable quarterly in arrears at a fixed rate of 6.50% per annum from the original issuance date to, but excluding, July 15, 2025 , and from (and including) that date at a floating rate equal to three-month LIBOR plus a spread of 4.06% per annum. Series C Preferred Stock In March 2012, the Company issued and sold 126,500 shares of non-cumulative perpetual convertible preferred stock, Series C, liquidation preference $1,000 per share (the “Series C Preferred Stock”) for $126.5 million in a public offering. When, as and if declared, dividends on the Series C Preferred Stock were payable quarterly in arrears at a rate of 5.00% per annum. The Series C Preferred Stock was convertible into common stock at the option of the holder subject to customary anti-dilution adjustments. Additionally, on and after April 15, 2017, the Company had the right under certain circumstances to cause the Series C Preferred Stock to be converted into common stock if the closing price of the Company’s common stock exceeded a certain amount. In 2016 , pursuant to such terms, 30 shares of the Series C Preferred Stock were converted at the option of the respective holders into 729 shares of the Company's common stock. On April 25, 2017 , 2,073 shares of the Series C Preferred Stock were converted at the option of the respective holder into 51,244 shares of the Company's common stock, pursuant to the terms of the Series C Preferred Stock. On April 27, 2017 , the Company caused a mandatory conversion of its remaining 124,184 shares of Series C Preferred Stock into 3,069,828 shares of the Company's common stock at a conversion rate of 24.72 shares of common stock per share of Series C Preferred Stock. Cash was paid in lieu of fractional shares for an amount considered insignificant. Common Stock Warrant Pursuant to the U.S. Department of the Treasury’s (the “U.S. Treasury”) Capital Purchase Program, on December 19, 2008, the Company issued to the U.S. Treasury a warrant to exercise 1,643,295 warrant shares of Wintrust common stock with a term of 10 years. The exercise price, subject to customary anti-dilution, was $22.66 at September 30, 2017 . In February 2011, the U.S. Treasury sold all of its interest in the warrant issued to it in a secondary underwritten public offering. During the first nine months of 2017 294,993 warrant shares were exercised, which resulted in 202,325 shares of common stock issued. At September 30, 2017 , all remaining holders of the interest in the warrant were able to exercise 46,859 warrant shares. Other At the January 2017 Board of Directors meeting, a quarterly cash dividend of $0.14 per share ( $0.56 on an annualized basis) was declared. It was paid on February 23, 2017 to shareholders of record as of February 9, 2017 . At the April 2017 Board of Directors meeting, a quarterly cash dividend of $0.14 per share ( $0.56 on an annualized basis) was declared. It was paid on May 25, 2017 to shareholders of record as of May 11, 2017 . At the July 2017 Board of Directors meeting, a quarterly cash dividend of $0.14 per share ( $0.56 on an annualized basis) was declared. It was paid on August 24, 2017 to shareholders of record as of August 10, 2017. Accumulated Other Comprehensive Income (Loss) The following tables summarize the components of other comprehensive income (loss), including the related income tax effects, and the related amount reclassified to net income for the periods presented (in thousands). Accumulated Unrealized Gains (Losses) on Securities Accumulated Unrealized Losses on Derivative Instruments Accumulated Foreign Currency Translation Adjustments Total Accumulated Other Comprehensive Loss Balance at July 1, 2017 $ (15,022 ) $ 4,959 $ (36,474 ) $ (46,537 ) Other comprehensive income (loss) during the period, net of tax, before reclassifications 653 228 4,206 5,087 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (24 ) 8 — (16 ) Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax (20 ) — — (20 ) Net other comprehensive income during the period, net of tax $ 609 $ 236 $ 4,206 $ 5,051 Balance at September 30, 2017 $ (14,413 ) $ 5,195 $ (32,268 ) $ (41,486 ) Balance at January 1, 2017 $ (29,309 ) $ 4,165 $ (40,184 ) $ (65,328 ) Other comprehensive income (loss) during the period, net of tax, before reclassifications 15,815 393 7,916 24,124 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (19 ) 637 — 618 Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax $ (900 ) $ — $ — $ (900 ) Net other comprehensive income during the period, net of tax $ 14,896 $ 1,030 $ 7,916 $ 23,842 Balance at September 30, 2017 $ (14,413 ) $ 5,195 $ (32,268 ) $ (41,486 ) Balance at July 1, 2016 $ 3,971 $ (2,220 ) $ (36,191 ) $ (34,440 ) Other comprehensive income (loss) during the period, net of tax, before reclassifications 1,532 1,037 (1,644 ) 925 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (2,005 ) 646 — (1,359 ) Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax 2,295 — — 2,295 Net other comprehensive income (loss) during the period, net of tax $ 1,822 $ 1,683 $ (1,644 ) $ 1,861 Balance at September 30, 2016 $ 5,793 $ (537 ) $ (37,835 ) $ (32,579 ) Balance at January 1, 2016 $ (17,674 ) $ (2,193 ) $ (42,841 ) $ (62,708 ) Other comprehensive income during the period, net of tax, before reclassifications 20,444 66 5,006 25,516 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (3,684 ) 1,590 — (2,094 ) Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax 6,707 — — 6,707 Net other comprehensive income during the period, net of tax $ 23,467 $ 1,656 $ 5,006 $ 30,129 Balance at September 30, 2016 $ 5,793 $ (537 ) $ (37,835 ) $ (32,579 ) Amount Reclassified from Accumulated Other Comprehensive Income for the Details Regarding the Component of Accumulated Other Comprehensive Income Three Months Ended Nine Months Ended Impacted Line on the Consolidated Statements of Income September 30, September 30, 2017 2016 2017 2016 Accumulated unrealized losses on securities Gains included in net income $ 39 $ 3,305 $ 31 $ 6,070 Gains on investment securities, net 39 3,305 31 6,070 Income before taxes Tax effect $ (15 ) $ (1,300 ) $ (12 ) $ (2,386 ) Income tax expense Net of tax $ 24 $ 2,005 $ 19 $ 3,684 Net income Accumulated unrealized losses on derivative instruments Amount reclassified to interest expense on deposits $ (380 ) $ 528 $ (15 ) $ 1,121 Interest on deposits Amount reclassified to interest expense on junior subordinated debentures 394 537 $ 1,066 $ 1,499 Interest on junior subordinated debentures (14 ) (1,065 ) (1,051 ) (2,620 ) Income before taxes Tax effect $ 6 $ 419 $ 414 $ 1,030 Income tax expense Net of tax $ (8 ) $ (646 ) $ (637 ) $ (1,590 ) Net income Earnings per Share The following table shows the computation of basic and diluted earnings per share for the periods indicated: Three Months Ended Nine Months Ended (In thousands, except per share data) September 30, September 30, September 30, September 30, Net income $ 65,626 $ 53,115 $ 188,901 $ 152,267 Less: Preferred stock dividends 2,050 3,628 7,728 10,884 Net income applicable to common shares—Basic (A) 63,576 49,487 181,173 141,383 Add: Dividends on convertible preferred stock, if dilutive — 1,578 1,578 4,735 Net income applicable to common shares—Diluted (B) 63,576 51,065 182,751 146,118 Weighted average common shares outstanding (C) 55,796 51,679 54,292 49,763 Effect of dilutive potential common shares Common stock equivalents 966 938 988 822 Convertible preferred stock, if dilutive — 3,109 1,317 3,109 Total dilutive potential common shares 966 4,047 2,305 3,931 Weighted average common shares and effect of dilutive potential common shares (D) 56,762 55,726 56,597 53,694 Net income per common share: Basic (A/C) $ 1.14 $ 0.96 $ 3.34 $ 2.84 Diluted (B/D) $ 1.12 $ 0.92 $ 3.23 $ 2.72 Potentially dilutive common shares can result from stock options, restricted stock unit awards, stock warrants, the Company’s convertible preferred stock and shares to be issued under the Employee Stock Purchase Plan and the Directors Deferred Fee and Stock Plan, being treated as if they had been either exercised or issued, computed by application of the treasury stock method. While potentially dilutive common shares are typically included in the computation of diluted earnings per share, potentially dilutive common shares are excluded from this computation in periods in which the effect would reduce the loss per share or increase the income per share. For diluted earnings per share, net income applicable to common shares can be affected by the conversion of the Company’s convertible preferred stock. Where the effect of this conversion would reduce the loss per share or increase the income per share for a period, net income applicable to common shares is not adjusted by the associated preferred dividends.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 16, 2017 , the Company entered in agreements with the FDIC that terminate all existing loss share agreements with the FDIC. The remaining loss share agreements were related to the Company’s acquisition of assets and assumption of liabilities of eight failed banks through FDIC assisted transactions in 2010, 2011 and 2012. Under terms of the agreements, the Company made a net payment of $15.2 million to the FDIC as consideration for the early termination of the loss share agreements. The Company recorded a pre-tax gain of approximately $0.4 million in the fourth quarter of 2017 to write off the remaining loss share asset, relieve the claw-back liability and recognize the payment to the FDIC.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Accounting	The consolidated financial statements of Wintrust Financial Corporation and Subsidiaries (“Wintrust” or “the Company”) presented herein are unaudited, but in the opinion of management reflect all necessary adjustments of a normal or recurring nature for a fair presentation of results as of the dates and for the periods covered by the consolidated financial statements. The accompanying consolidated financial statements are unaudited and do not include information or footnotes necessary for a complete presentation of financial condition, results of operations or cash flows in accordance with U.S. generally accepted accounting principles ("GAAP"). The unaudited consolidated financial statements should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016 (“ 2016 Form 10-K”). Operating results reported for the period are not necessarily indicative of the results which may be expected for the entire year. Reclassifications of certain prior period amounts have been made to conform to the current period presentation. The preparation of the financial statements requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities. Management believes that the estimates made are reasonable, however, changes in estimates may be required if economic or other conditions develop differently from management’s expectations. Certain policies and accounting principles inherently have a greater reliance on the use of estimates, assumptions and judgments and as such have a greater possibility of producing results that could be materially different than originally reported. Management views critical accounting policies to be those which are highly dependent on subjective or complex judgments, estimates and assumptions, and where changes in those estimates and assumptions could have a significant impact on the financial statements. Management currently views the determination of the allowance for loan losses, allowance for covered loan losses and the allowance for losses on lending-related commitments, loans acquired with evidence of credit quality deterioration since origination, estimations of fair value, the valuations required for impairment testing of goodwill, the valuation and accounting for derivative instruments and income taxes as the accounting areas that require the most subjective and complex judgments, and as such could be the most subject to revision as new information becomes available. Descriptions of the Company's significant accounting policies are included in Note 1 - “Summary of Significant Accounting Policies” of the 2016 Form 10-K.
Recent Accounting Developments	Revenue Recognition In May 2014, the FASB issued ASU No. 2014-09, which created “Revenue from Contracts with Customers (Topic 606),” to clarify the principles for recognizing revenue and develop a common revenue standard for customer contracts. This ASU provides guidance regarding how 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. The ASU also added a new subtopic to the codification, ASC 340-40, “Other Assets and Deferred Costs: Contracts with Customers” to provide guidance on costs related to obtaining and fulfilling a customer contract. Furthermore, the new standard requires disclosure of sufficient information to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. At the time ASU No. 2014-09 was issued, the guidance was effective for fiscal years beginning after December 15, 2016. In July 2015, the FASB approved a deferral of the effective date by one year, which would result in the guidance becoming effective for fiscal years beginning after December 15, 2017. The FASB has continued to issue various Updates to clarify and improve specific areas of ASU No. 2014-09. In March 2016, the FASB issued ASU No. 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” to clarify the implementation guidance within ASU No. 2014-09 surrounding principal versus agent considerations and its impact on revenue recognition. In April 2016, the FASB issued ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” to also clarify the implementation guidance within ASU No. 2014-09 related to these two topics. In May 2016, the FASB issued ASU No. 2016-11, “Revenue Recognition (Topic 605) and Derivative and Hedging (Topic 815): Rescission of SEC Guidance Because of Accounting Standards Updates 2014-09 and 2014-16 Pursuant to Staff Announcements at the March 3, 2016 EITF Meeting,” to remove certain areas of SEC Staff Guidance from those specific Topics. In May 2016 and December 2016, the FASB issued ASU 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients” and ASU 2016-20, “Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers,” to clarify specific aspects of implementation, including the collectability criterion, exclusion of sales taxes collected from a transaction price, noncash consideration, contract modifications, completed contracts at transition, the applicability of loan guarantee fees, impairment of capitalized contract costs and certain disclosure requirements. In February 2017, the FASB issued ASU No. 2017-05, “Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets,” to clarify the implementation guidance within ASU No. 2014-09 surrounding transfers of nonfinancial assets, including partial sales of such assets, and its impact on revenue recognition. Like ASU No. 2014-09, this guidance is effective for fiscal years beginning after December 15, 2017. The Company continues to evaluate the impact on the consolidated financial statements of adopting this new guidance. As certain significant revenue sources related to financial instruments such as interest income are considered not in-scope, the Company does not believe the new guidance will have a significant impact on its consolidated financial statements. The Company is currently completing reviews of specific contracts with customers across its various sources of revenue, primarily related to revenue from its wealth management segment. Contract reviews assist in identifying any characteristics of such contracts that could result in a change in the Company's current practices for recognition of revenue and recognition of costs incurred to obtain or fulfill such contracts. Additionally, during these contract reviews, the Company is considering any disclosure impact that may arise from characteristics identified. The Company expects to adopt the new guidance using the modified retrospective approach. Financial Instruments In January 2016, the FASB issued ASU No. 2016-01, “ Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, ” to improve the accounting for financial instruments. This ASU requires equity investments with readily determinable fair values to be measured at fair value with changes recognized in net income regardless of classification. For equity investments without a readily determinable fair value, the value of the investment would be measured at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer instead of fair value, unless a qualitative assessment indicates impairment. Additionally, this ASU requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. This guidance is effective for fiscal years beginning after December 15, 2017 and is to be applied prospectively with a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Leases In February 2016, the FASB issued ASU No. 2016-02, “ Leases (Topic 842), ” to improve transparency and comparability across entities regarding leasing arrangements. This ASU requires the recognition of a separate lease liability representing the required discounted lease payments over the lease term and a separate lease asset representing the right to use the underlying asset during the same lease term. Additionally, this ASU provides clarification regarding the identification of certain components of contracts that would represent a lease as well as requires additional disclosures to the notes of the financial statements. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach, including the option to apply certain practical expedients. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements. Excluding any impact from the clarification of contracts representing a lease, the Company expects to recognize separate lease liabilities and right to use assets for the amounts related to certain facilities under operating lease agreements disclosed in Note 15 - Minimum Lease Commitments in the 2016 Form 10-K . Additionally, the Company does not expect to significantly change operating lease agreements prior to adoption. Derivatives In March 2016, the FASB issued ASU No. 2016-05, “ Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships, ” to clarify guidance surrounding the effect on an existing hedging relationship of a change in the counterparty to a derivative instrument that has been designated as a hedging instrument. This ASU states that a change in counterparty to such derivative instrument does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. This guidance was effective for fiscal years beginning after December 15, 2016 and did not have a material impact on the Company's consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, “ Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, ” to improve the financial reporting of hedging relationships to better align the economic results of an entity’s risk management activities and disclosures within its financial statements. In addition, this ASU makes certain targeted improvements to simplify the application of the hedge accounting to derivative instruments. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Guidance related to existing cash flow hedges is to be applied under a modified retrospective approach and guidance related to amended presentation and disclosures is to be applied under a prospective approach. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements. Equity Method Investments In March 2016, the FASB issued ASU No. 2016-07, “ Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting, ” to simplify the accounting for investments qualifying for the use of the equity method of accounting. This ASU eliminates the requirement to retroactively adopt the equity method of accounting when an investment qualifies for such method as a result of an increase in the level of ownership interest or degree of influence. The ASU requires the equity method investor add the cost of acquiring the additional interest to the current basis and adopt the equity method of accounting as of that date going forward. Additionally, for available-for-sale equity securities that become qualified for equity method accounting, the ASU requires the related unrealized holding gains or losses included in accumulated other comprehensive income be recognized in earnings at the date the investment qualifies for such accounting. This guidance was effective for fiscal years beginning after December 15, 2016 and did not have a material impact on the Company's consolidated financial statements. Employee Share-Based Compensation In March 2016, the FASB issued ASU No. 2016-09, “ Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, ” to simplify the accounting for several areas of share-based payment transactions. This included the recognition of all excess tax benefits and tax deficiencies as income tax expense instead of surplus, the classification on the statement of cash flows of excess tax benefits and taxes paid when the employer withholds shares for tax-withholding purposes. Additionally, related to forfeitures, the ASU provides the option to estimate the number of awards that are expected to vest or account for forfeitures as they occur. This guidance was effective for fiscal years beginning after December 15, 2016. In the first nine months of 2017, the Company recorded $5.0 million of excess tax benefits within income tax expense on the Consolidated Statements of Income as a result of adoption. Allowance for Credit Losses In June 2016, the FASB issued ASU No. 2016-13, “ Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, ” to replace the current incurred loss methodology for recognizing credit losses, which delays recognition until it is probable a loss has been incurred, with a methodology that reflects an estimate of all expected credit losses and considers additional reasonable and supportable forecasted information when determining credit loss estimates. This impacts the calculation of the allowance for credit losses for all financial assets measured under the amortized cost basis, including PCI loans at the time of and subsequent to acquisition. Additionally, credit losses related to available-for-sale debt securities would be recorded through the allowance for credit losses and not as a direct adjustment to the amortized cost of the securities. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements as well as the impact on current systems and processes. Specifically, the Company has established a group consisting of individuals from the various areas of the Company tasked with transitioning to the new requirements. At this time, the Company is reviewing potential methodologies for estimating expected credit losses using reasonable and supportable forecast information and has identified certain historical data and system requirements. Statement of Cash Flows In August 2016, the FASB issued ASU No. 2016-15, “ Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the FASB Emerging Issues Task Force), ” to clarify the presentation of specific types of cash flow receipts and payments, including the payment of debt prepayment or debt extinguishment costs, contingent consideration cash payments paid subsequent to the acquisition date and proceeds from settlement of BOLI policies . This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a retrospective approach, if practicable. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18 “ Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force), ” to clarify the classification and presentation of changes in restricted cash on the statement of cash flows . This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a retrospective approach. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Income Taxes In October 2016, the FASB issued ASU No. 2016-16, “Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory,” to improve the accounting for intra-entity transfers of assets other than inventory. This ASU allows the recognition of current and deferred income taxes for such transfers prior to the subsequent sale of the transferred assets to an outside party. Initial recognition of current and deferred income taxes is currently prohibited for intra-entity transfers of assets other than inventory. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach through cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Consolidation In October 2016, the FASB issued ASU No. 2016-17, “ Consolidation (Topic 810): Interest Held through Related Parties That Are under Common Control, ” to amend guidance from ASU No. 2015-02 regarding how a reporting entity treats indirect interests in a variable interest entity (“VIE”) held through related parties under common control when determining whether the reporting entity is the primary beneficiary of such VIE . This guidance was effective for fiscal years beginning after December 15, 2016 and did not have a material impact on the Company's consolidated financial statements. Business Combinations In January 2017, the FASB issued ASU No. 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business,” to improve such definition and, as a result, assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or as business combinations. The definition of a business impacts many areas of accounting including acquisitions, disposals, goodwill and consolidation. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a prospective approach. The Company expects the adoption of this new guidance to impact the determination of whether future acquisitions are considered a business combination and the resulting impact of such determination on the consolidated financial statements. Goodwill In January 2017, the FASB issued ASU No. 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,” to simplify the subsequent measurement of goodwill. When the carrying amount of a reporting unit exceeds its fair value, an entity would no longer be required to determine goodwill impairment by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit was acquired in a business combination. Goodwill impairment would be recognized according to the excess of the carrying amount of the reporting unit over the calculated fair value of such unit. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and is to be applied under a prospective approach. The Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Compensation In March 2017, the FASB issued ASU No. 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,” to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost. An entity will be required to report the service cost component of such costs in the same line item or items as other compensation costs related to services rendered. Additionally, only the service cost component will be eligible for capitalization when applicable. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a retrospective approach related to presentation of the service cost component and a prospective approach related to capitalization of such costs. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. When adopted, the Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, “Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting,” to clarify when modification accounting is appropriate for changes to the terms and conditions of a share-based payment award. An entity will be required to account for such changes as a modification unless certain criteria is met. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, and is to be applied under a prospective approach for awards modified on or after the adoption date. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. When adopted, the Company does not expect this guidance to have a material impact on the Company's consolidated financial statements. Amortization of Premium on Certain Debt Securities In March 2017, the FASB issued ASU No. 2017-08, “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities,” to amend the amortization period for certain purchased callable debt securities held at a premium. The amortization period for such securities will be shortened to the earliest call date. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and is to be applied under a modified retrospective approach. Early adoption is permitted as of the beginning of an annual period that has not been issued or made available for issuance. The Company has not early adopted this guidance. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements.
FDIC-Assisted Transactions	FDIC-Assisted Transactions From 2010 to 2012, the Company acquired the banking operations, including the acquisition of certain assets and the assumption of liabilities, of nine financial institutions in FDIC-assisted transactions. Loans comprise the majority of the assets acquired in nearly all of these FDIC-assisted transactions, of which eight such transactions are subject to loss sharing agreements with the FDIC whereby the FDIC has agreed to reimburse the Company for 80% of losses incurred on the purchased loans, other real estate owned (“OREO”), and certain other assets. Additionally, clawback provisions within these loss share agreements with the FDIC require the Company to reimburse the FDIC in the event that actual losses on covered assets are lower than the original loss estimates agreed upon with the FDIC with respect of such assets in the loss share agreements. The Company refers to the loans subject to these loss sharing agreements as “covered loans” and uses the term “covered assets” to refer to covered loans, covered OREO and certain other covered assets during periods subject to such agreements. The agreements with the FDIC require that the Company follow certain servicing procedures or risk losing the FDIC reimbursement of covered asset losses. As of dates subject to such agreements, the loans covered by loss share agreements are classified and presented as covered loans and the estimated reimbursable losses are recorded as an FDIC indemnification asset or other liability in the Consolidated Statements of Condition. The Company recorded the acquired assets and liabilities at their estimated fair values at the acquisition date. The fair value for loans reflected expected credit losses at the acquisition date. Therefore, the Company will only recognize a provision for credit losses and charge-offs on the acquired loans for any further credit deterioration subsequent to the acquisition date. See Note 7 — Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans for further discussion of the allowance on covered loans. The loss share agreements with the FDIC cover realized losses on loans, foreclosed real estate and certain other assets and require the Company to record loss share assets and liabilities that are measured separately from the loan portfolios because they are not contractually embedded in the loans and are not transferable with the loans should the Company choose to dispose of them. Fair values at the acquisition dates were estimated based on projected cash flows available for loss share based on the credit adjustments estimated for each loan pool and the loss share percentages. The loss share assets and liabilities are recorded as FDIC indemnification assets and other liabilities, respectively, on the Consolidated Statements of Condition as of dates covered by loss share agreements. Subsequent to the acquisition date, reimbursements received from the FDIC for actual incurred losses will reduce the FDIC indemnification assets. Reductions to expected losses, to the extent such reductions to expected losses are the result of an improvement to the actual or expected cash flows from the covered assets, will also reduce the FDIC indemnification assets and, if necessary, increase any loss share liability when necessary reductions exceed the current value of the FDIC indemnification assets. In accordance with the clawback provision noted above, the Company may be required to reimburse the FDIC when actual losses are less than certain thresholds established for each loss share agreement. The balance of these estimated reimbursements in accordance with clawback provisions and any related amortization are adjusted periodically for changes in the expected losses on covered assets. On the Consolidated Statements of Condition as of dates subject to loss share agreements, estimated reimbursements from clawback provisions are recorded as a reduction to the FDIC indemnification asset or, if necessary, an increase to the loss share liability, which is included within accrued interest payable and other liabilities. In the second quarter of 2017, the Company recorded a $4.9 million reduction to the estimated loss share liability as a result of an adjustment related to such clawback provisions. Although these assets are contractual receivables from the FDIC and these liabilities are contractual payables to the FDIC, there are no contractual interest rates. Additional expected losses, to the extent such expected losses result in recognition of an allowance for covered loan losses, will increase the FDIC indemnification asset or reduce the FDIC indemnification liability. The corresponding amortization is recorded as a component of non-interest income on the Consolidated Statements of Income during periods covered by loss share agreements.
PCI Loans	PCI Loans Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date. Expected future cash flows at the purchase date in excess of the fair value of loans are recorded as interest income over the life of the loans if the timing and amount of the future cash flows is reasonably estimable (“accretable yield”). The difference between contractually required payments and the cash flows expected to be collected at acquisition is referred to as the non-accretable difference and represents probable losses in the portfolio. In determining the acquisition date fair value of PCI loans, and in subsequent accounting, the Company aggregates these purchased loans into pools of loans by common risk characteristics, such as credit risk rating and loan type. Subsequent to the purchase date, increases in cash flows over those expected at the purchase date are recognized as interest income prospectively. Subsequent decreases to the expected cash flows will generally result in a provision for loan losses. The Company purchased a portfolio of life insurance premium finance receivables in 2009. These purchased life insurance premium finance receivables are valued on an individual basis. If credit related conditions deteriorate, an allowance related to these loans will be established as part of the provision for credit losses.
Cash and Cash Equivalents	For purposes of the Consolidated Statements of Cash Flows, the Company considers cash and cash equivalents to include cash on hand, cash items in the process of collection, non-interest bearing amounts due from correspondent banks, federal funds sold and securities purchased under resale agreements with original maturities of three months or less.
Investment Securities	The Company conducts a regular assessment of its investment securities to determine whether securities are other-than-temporarily impaired considering, among other factors, the nature of the securities, credit ratings or financial condition of the issuer, the extent and duration of the unrealized loss, expected cash flows, market conditions and the Company’s ability to hold the securities through the anticipated recovery period. The Company does not consider securities with unrealized losses at September 30, 2017 to be other-than-temporarily impaired. The Company does not intend to sell these investments and it is more likely than not that the Company will not be required to sell these investments before recovery of the amortized cost bases, which may be the maturity dates of the securities. The unrealized losses within each category have occurred as a result of changes in interest rates, market spreads and market conditions subsequent to purchase. Securities with continuous unrealized losses existing for more than twelve months were primarily corporate notes and mortgage-backed securities. Unrealized losses recognized on corporate notes and mortgage-backed securities are the result of increases in yields for similar types of securities.
Finance, Loans and Leases Receivable	Certain premium finance receivables are recorded net of unearned income.
Receivables	These amounts include accretion from both covered and non-covered loans, and are both included within interest and fees on loans in the Consolidated Statements of Income.
Allowance and Nonperforming Loans, Allowance	As a result of this initial review by the Company’s Managed Asset Division, the credit risk rating is reviewed and a portion of the outstanding loan balance may be deemed uncollectible or an impairment reserve may be established. The Company’s impairment analysis utilizes an independent re-appraisal of the collateral (unless such a third-party evaluation is not possible due to the unique nature of the collateral, such as a closely-held business or thinly traded securities). In the case of commercial real estate collateral, an independent third party appraisal is ordered by the Company’s Real Estate Services Group to determine if there has been any change in the underlying collateral value. These independent appraisals are reviewed by the Real Estate Services Group and sometimes by independent third party valuation experts and may be adjusted depending upon market conditions. Through the credit risk rating process, loans are reviewed to determine if they are performing in accordance with the original contractual terms. If the borrower has failed to comply with the original contractual terms, further action may be required by the Company, including a downgrade in the credit risk rating, movement to non-accrual status, a charge-off or the establishment of a specific impairment reserve. If a loan amount, or portion thereof, is determined to be uncollectible, the loan’s credit risk rating is immediately downgraded to an 8 or 9 and the uncollectible amount is charged-off. Any loan that has a partial charge-off continues to be assigned a credit risk rating of an 8 or 9 for the duration of time that a balance remains outstanding. The Company undertakes a thorough and ongoing analysis to determine if additional impairment and/or charge-offs are appropriate and to begin a workout plan for the credit to minimize actual losses. If, based on current information and events, it is probable that the Company will be unable to collect all amounts due to it according to the contractual terms of the loan agreement, a specific impairment reserve is established. In determining the appropriate charge-off for collateral-dependent loans, the Company considers the results of appraisals for the associated collateral.
Loans and Leases Receivable, Nonperforming Loan and Lease	Non-performing loans include all non-accrual loans (8 and 9 risk ratings) as well as loans 90 days past due and still accruing interest, excluding PCI and covered loans. The remainder of the portfolio is considered performing under the contractual terms of the loan agreement.
Loans and Leases Receivable, Allowance for Loan Losses	In conjunction with FDIC-assisted transactions, the Company entered into loss share agreements with the FDIC. Additional expected losses, to the extent such expected losses result in the recognition of an allowance for loan losses, will increase the FDIC loss share asset or reduce any FDIC loss share liability. The allowance for loan losses for loans acquired in FDIC-assisted transactions is determined without giving consideration to the amounts recoverable through loss share agreements (since the loss share agreements are separately accounted for and thus presented “gross” on the balance sheet). On the Consolidated Statements of Income, the provision for credit losses is reported net of changes in the amount recoverable under the loss share agreements during the period subject to loss share agreement. Reductions to expected losses, to the extent such reductions to expected losses are the result of an improvement to the actual or expected cash flows from the covered assets, will reduce the FDIC loss share asset or increase any FDIC loss share liability. Additions to expected losses will require an increase to the allowance for covered loan losses, and a corresponding increase to the FDIC loss share asset or reduction to any FDIC loss share liability.
Impaired Financing Receivable	These impaired loans require an allowance for loan losses because the estimated fair value of the loans or related collateral is less than the recorded investment in the loans. Impaired loans are considered by the Company to be non-accrual loans, TDRs or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest. A loan is considered to be impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due pursuant to the contractual terms of the loan agreement. A loan modified in a TDR is an impaired loan according to applicable accounting guidance. Impairment is measured by estimating the fair value of the loan based on the present value of expected cash flows, the market price of the loan, or the fair value of the underlying collateral. Impaired loans are considered a fair value measurement where an allowance is established based on the fair value of collateral. Appraised values, which may require adjustments to market-based valuation inputs, are generally used on real estate collateral-dependent impaired loans.
Loans and Leases Receivable, Troubled Debt Restructuring	The Company’s approach to restructuring loans, excluding PCI loans, is built on its credit risk rating system which requires credit management personnel to assign a credit risk rating to each loan. In each case, the loan officer is responsible for recommending a credit risk rating for each loan and ensuring the credit risk ratings are appropriate. These credit risk ratings are then reviewed and approved by the bank’s chief credit officer and/or concurrence credit officer. Credit risk ratings are determined by evaluating a number of factors including a borrower’s financial strength, cash flow coverage, collateral protection and guarantees. The Company’s credit risk rating scale is one through ten with higher scores indicating higher risk. In the case of loans rated six or worse following modification, the Company’s Managed Assets Division evaluates the loan and the credit risk rating and determines that the loan has been restructured to be reasonably assured of repayment and of performance according to the modified terms and is supported by a current, well-documented credit assessment of the borrower’s financial condition and prospects for repayment under the revised terms. A modification of a loan, excluding PCI loans, with an existing credit risk rating of 6 or worse or a modification of any other credit, which will result in a restructured credit risk rating of six or worse, must be reviewed for possible TDR classification. In that event, our Managed Assets Division conducts an overall credit and collateral review. A modification of these loans is considered to be a TDR if both (1) the borrower is experiencing financial difficulty and (2) for economic or legal reasons, the bank grants a concession to a borrower that it would not otherwise consider. The modification of a loan, excluding PCI loans, where the credit risk rating is 5 or better both before and after such modification is not considered to be a TDR. Based on the Company’s credit risk rating system, it considers that borrowers whose credit risk rating is 5 or better are not experiencing financial difficulties and therefore, are not considered TDRs. All credits determined to be a TDR will continue to be classified as a TDR in all subsequent periods, unless the borrower has been in compliance with the loan’s modified terms for a period of six months (including over a calendar year-end) and the current interest rate represents a market rate at the time of restructuring. The Managed Assets Division, in consultation with the respective loan officer, determines whether the modified interest rate represented a current market rate at the time of restructuring. Using knowledge of current market conditions and rates, competitive pricing on recent loan originations, and an assessment of various characteristics of the modified loan (including collateral position and payment history), an appropriate market rate for a new borrower with similar risk is determined. If the modified interest rate meets or exceeds this market rate for a new borrower with similar risk, the modified interest rate represents a market rate at the time of restructuring. Additionally, before removing a loan from TDR classification, a review of the current or previously measured impairment on the loan and any concerns related to future performance by the borrower is conducted. If concerns exist about the future ability of the borrower to meet its obligations under the loans based on a credit review by the Managed Assets Division, the TDR classification is not removed from the loan. TDRs are reviewed at the time of the modification and on a quarterly basis to determine if a specific reserve is necessary. The carrying amount of the loan is compared to the expected payments to be received, discounted at the loan's original rate, or for collateral dependent loans, to the fair value of the collateral. Any shortfall is recorded as a specific reserve. The Company, in accordance with ASC 310-10, continues to individually measure impairment of these loans after the TDR classification is removed. Each TDR was reviewed for impairment at September 30, 2017 and approximately $1.2 million of impairment was present and appropriately reserved for through the Company’s normal reserving methodology in the Company’s allowance for loan losses. For TDRs in which impairment is calculated by the present value of future cash flows, the Company records interest income representing the decrease in impairment resulting from the passage of time during the respective period, which differs from interest income from contractually required interest on these specific loans. During the three months ended September 30, 2017 and 2016 , the Company recorded $68,000 and $98,000 , respectively, of interest income, which was reflected as a decrease in impairment. For the nine months ended September 30, 2017 and 2016 , the Company recorded $172,000 and $323,000 , respectively, of interest income, which was reflected as a decrease in impairment. TDRs may arise in which, due to financial difficulties experienced by the borrower, the Company obtains through physical possession one or more collateral assets in satisfaction of all or part of an existing credit. Once possession is obtained, the Company reclassifies the appropriate portion of the remaining balance of the credit from loans to OREO, which is included within other assets in the Consolidated Statements of Condition. For any residential real estate property collateralizing a consumer mortgage loan, the Company is considered to possess the related collateral only if legal title is obtained upon completion of foreclosure, or the borrower conveys all interest in the residential real estate property to the Company through completion of a deed in lieu of foreclosure or similar legal agreement. Excluding covered OREO, at September 30, 2017 , the Company had $7.9 million of foreclosed residential real estate properties included within OREO.
Goodwill	At June 30, 2017, the Company utilized a quantitative approach for its annual goodwill impairment test of the community banking segment and determined that no impairment existed at that time. At December 31, 2016, the Company utilized a quantitative approach for its annual goodwill impairment tests of the specialty finance and wealth management segments and determined that no impairment existed at that time. At each reporting date between annual goodwill impairment tests, the Company considers potential indicators of impairment. As of September 30, 2017 , the Company identified no such indicators of goodwill impairment for each business segment.
Intangible Assets	The core deposit intangibles recognized in connection with prior bank acquisitions are amortized over a ten -year period on an accelerated basis. The customer list intangibles recognized in connection with the purchase of life insurance premium finance assets in 2009 are being amortized over an 18 -year period on an accelerated basis while the customer list intangibles recognized in connection with prior acquisitions within the wealth management segment are being amortized over a ten -year period on a straight-line basis.
Offsetting Assets and Liabilities	The Company records securities sold under repurchase agreements at their gross value and does not offset positions on the Consolidated Statements of Condition.
Repurchase Agreements	Securities pledged for customer balances in sweep accounts and short-term borrowings from brokers are maintained under the Company’s control and consist of U.S. Government agency and mortgage-backed securities. These securities are included in the available-for-sale and held-to-maturity securities portfolios as reflected on the Company’s Consolidated Statements of Condition.
Debt	These transactions were not considered sales of receivables and, as such, related proceeds received are reflected on the Company’s Consolidated Statements of Condition as a secured borrowing owed to the unrelated third party, net of unamortized debt issuance costs, and translated to the Company’s reporting currency as of the respective date. These notes are stated at par adjusted for unamortized costs paid related to the issuance of this debt. As no outstanding balance exists on the Revolving Credit Facility, unamortized costs paid by the Company in relation to the issuance of this debt are classified in other assets on the Consolidated Statements of Condition. The Term Facility is stated at par of the current outstanding balance of the debt adjusted for unamortized costs paid by the Company in relation to the debt issuance. FHLB advances are stated at par value of the debt adjusted for unamortized prepayment fees paid at the time of prior restructurings of FHLB advances and unamortized fair value adjustments recorded in connection with advances acquired through acquisitions.
Transfers and Servicing of Financial Assets, Transfers of Financial Assets	The remaining $12.7 million within secured borrowings at September 30, 2017 represents other sold interests in certain loans by the Company that were not considered sales and, as such, related proceeds received are reflected on the Company’s Consolidated Statements of Condition as a secured borrowing owed to the various unrelated third parties.
Junior Subordinated Debentures	The Trusts are reported in the Company’s consolidated financial statements as unconsolidated subsidiaries. Accordingly, in the Consolidated Statements of Condition, the junior subordinated debentures issued by the Company to the Trusts are reported as liabilities and the common securities of the Trusts, all of which are owned by the Company, are included in available-for-sale securities.
Segment Reporting	The Company’s operations consist of three primary segments: community banking, specialty finance and wealth management. The three reportable segments are strategic business units that are separately managed as they offer different products and services and have different marketing strategies. In addition, each segment’s customer base has varying characteristics and each segment has a different regulatory environment. While the Company’s management monitors each of the fifteen bank subsidiaries’ operations and profitability separately, these subsidiaries have been aggregated into one reportable operating segment due to the similarities in products and services, customer base, operations, profitability measures, and economic characteristics. For purposes of internal segment profitability, management allocates certain intersegment and parent company balances. Management allocates a portion of revenues to the specialty finance segment related to loans and leases originated by the specialty finance segment and sold or assigned to the community banking segment. Similarly, for purposes of analyzing the contribution from the wealth management segment, management allocates a portion of the net interest income earned by the community banking segment on deposit balances of customers of the wealth management segment to the wealth management segment. See Note 9 — Deposits, for more information on these deposits. Finally, expenses incurred at the Wintrust parent company are allocated to each segment based on each segment's risk-weighted assets. The segment financial information provided in the following tables has been derived from the internal profitability reporting system used by management to monitor and manage the financial performance of the Company. The accounting policies of the segments are substantially similar to those described in “Summary of Significant Accounting Policies” in Note 1 of the Company’s 2016 Form 10-K. The Company evaluates segment performance based on after-tax profit or loss and other appropriate profitability measures common to each segment.
Derivatives	For derivatives designated and that qualify as fair value hedges, the gain or loss on the derivative as well as the offsetting loss or gain on the hedged item attributable to the hedged risk are recognized in earnings. The Company includes the gain or loss on the hedged item in the same line item as the offsetting loss or gain on the related derivatives. Periodically, the Company will sell options to a bank or dealer for the right to purchase certain securities held within the banks’ investment portfolios (covered call options). These option transactions are designed primarily to mitigate overall interest rate risk and to increase the total return associated with the investment securities portfolio. These options do not qualify as accounting hedges pursuant to ASC 815, and, accordingly, changes in fair value of these contracts are recognized as other non-interest income. The effective portion of changes in the fair value of these cash flow hedges is recorded in accumulated other comprehensive income and is subsequently reclassified to interest expense as interest payments are made on the Company’s variable rate junior subordinated debentures. The changes in fair value (net of tax) are separately disclosed in the Consolidated Statements of Comprehensive Income. The ineffective portion of the change in fair value of these derivatives is recognized directly in earnings; however, no hedge ineffectiveness was recognized during the nine months ended September 30, 2017 or September 30, 2016 . The Company uses the hypothetical derivative method to assess and measure hedge effectiveness. In most cases, the offsetting derivatives have mirror-image terms, which result in the positions’ changes in fair value substantially offsetting through earnings each period. However, to the extent that the derivatives are not a mirror-image and because of differences in counterparty credit risk, changes in fair value will not completely offset resulting in some earnings impact each period. Changes in the fair value of these derivatives are included in non-interest income. Interest rate swaps designated as fair value hedges involve the payment of fixed amounts to a counterparty in exchange for the Company receiving variable payments over the life of the agreements without the exchange of the underlying notional amount. The fair values of these derivatives were estimated based on changes in mortgage rates from the dates of the commitments. Changes in the fair value of these mortgage banking derivatives are included in mortgage banking revenue. The Company recognizes derivative financial instruments in the consolidated financial statements at fair value regardless of the purpose or intent for holding the instrument. The Company records derivative assets and derivative liabilities on the Consolidated Statements of Condition within accrued interest receivable and other assets and accrued interest payable and other liabilities, respectively. Changes in the fair value of derivative financial instruments are either recognized in income or in shareholders’ equity as a component of other comprehensive income depending on whether the derivative financial instrument qualifies for hedge accounting and, if so, whether it qualifies as a fair value hedge or cash flow hedge. Generally, changes in fair values of derivatives accounted for as fair value hedges are recorded in income in the same period and in the same income statement line as changes in the fair values of the hedged items that relate to the hedged risk(s). Changes in fair values of derivative financial instruments accounted for as cash flow hedges, to the extent they are effective hedges, are recorded as a component of other comprehensive income, net of deferred taxes, and reclassified to earnings when the hedged transaction affects earnings. Changes in fair values of derivative financial instruments not designated in a hedging relationship pursuant to ASC 815, including changes in fair value related to the ineffective portion of cash flow hedges, are reported in non-interest income during the period of the change. Derivative financial instruments are valued by a third party and are corroborated by comparison with valuations provided by the respective counterparties. Fair values of certain mortgage banking derivatives (interest rate lock commitments and forward commitments to sell mortgage loans) are estimated based on changes in mortgage interest rates from the date of the loan commitment. The fair value of foreign currency derivatives is computed based on changes in foreign currency rates stated in the contract compared to those prevailing at the measurement date. Changes in the fair value of derivatives not designated in hedging relationships are recorded directly in earnings.
Derivatives, Offsetting Fair Value Amounts	The Company records interest rate derivatives subject to master netting agreements at their gross value and does not offset derivative assets and liabilities on the Consolidated Statements of Condition.
Fair Value of Financial Instruments	The Company measures, monitors and discloses certain of its assets and liabilities on a fair value basis. These financial assets and financial liabilities are measured at fair value in three levels, based on the markets in which the assets and liabilities are traded and the observability of the assumptions used to determine fair value. These levels are: • Level 1—unadjusted quoted prices in active markets for identical assets or liabilities. • Level 2 — inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3—significant unobservable inputs that reflect the Company’s own assumptions that market participants would use in pricing the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. A financial instrument’s categorization within the above valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the assets or liabilities. Following is a description of the valuation methodologies used for the Company’s assets and liabilities measured at fair value on a recurring basis. Available-for-sale and trading account securities —Fair values for available-for-sale and trading securities are typically based on prices obtained from independent pricing vendors. Securities measured with these valuation techniques are generally classified as Level 2 of the fair value hierarchy. Typically, standard inputs such as benchmark yields, reported trades for similar securities, issuer spreads, benchmark securities, bids, offers and reference data including market research publications are used to fair value a security. When these inputs are not available, broker/dealer quotes may be obtained by the vendor to determine the fair value of the security. We review the vendor’s pricing methodologies to determine if observable market information is being used, versus unobservable inputs. Fair value measurements using significant inputs that are unobservable in the market due to limited activity or a less liquid market are classified as Level 3 in the fair value hierarchy. The Company’s Investment Operations Department is responsible for the valuation of Level 3 available-for-sale securities. The methodology and variables used as inputs in pricing Level 3 securities are derived from a combination of observable and unobservable inputs. The unobservable inputs are determined through internal assumptions that may vary from period to period due to external factors, such as market movement and credit rating adjustments. At September 30, 2017 , the Company classified $68.4 million of municipal securities as Level 3. These municipal securities are bond issues for various municipal government entities primarily located in the Chicago metropolitan area and southern Wisconsin and are privately placed, non-rated bonds without CUSIP numbers. The Company also classified $3.9 million of U.S. government agencies as Level 3 at September 30, 2017 . The Company’s methodology for pricing these securities focuses on three distinct inputs: equivalent rating, yield and other pricing terms. To determine the rating for a given non-rated municipal bond, the Investment Operations Department references a publicly issued bond by the same issuer if available. A reduction is then applied to the rating obtained from the comparable bond, as the Company believes if liquidated, a non-rated bond would be valued less than a similar bond with a verifiable rating. The reduction applied by the Company is one complete rating grade (i.e. a “AA” rating for a comparable bond would be reduced to “A” for the Company’s valuation). In the third quarter of 2017 , all of the ratings derived in the above process by Investment Operations were BBB or better, for both bonds with and without comparable bond proxies. The fair value measurement of municipal bonds is sensitive to the rating input, as a higher rating typically results in an increased valuation. The remaining pricing inputs used in the bond valuation are observable. Based on the rating determined in the above process, Investment Operations obtains a corresponding current market yield curve available to market participants. Other terms including coupon, maturity date, redemption price, number of coupon payments per year, and accrual method are obtained from the individual bond term sheets. Certain municipal bonds held by the Company at September 30, 2017 have a call date that has passed, and are now continuously callable. When valuing these bonds, the fair value is capped at par value as the Company assumes a market participant would not pay more than par for a continuously callable bond. To determine the rating for the U.S. government agency securities, the Investment Operations Department assigned a AAA rating as it is guaranteed by the U.S. government. At September 30, 2017 , December 31, 2016 and September 30, 2016 , the Company held no equity securities classified as Level 3. In prior periods, equity securities in Level 3 were primarily comprised of auction rate preferred securities. The Company’s valuation methodology at that time included modeling the contractual cash flows of the underlying preferred securities and applying a discount to these cash flows by a market spread derived from the market price of the securities underlying debt. In the third quarter of 2016, the Company exchanged these auction rate securities for the underlying preferred securities, resulting in a $2.4 million gain on the nonmonetary sale. The Company classified the preferred securities received as Level 2 in the fair value hierarchy at the time of the transaction due to observable inputs other than quoted prices existing for the preferred securities. Mortgage loans held-for-sale —The fair value of mortgage loans held-for-sale is determined by reference to investor price sheets for loan products with similar characteristics. Loans held-for-investment —The fair value for loans in which the Company elected the fair value option is estimated by discounting future scheduled cash flows for the specific loan through maturity, adjusted for estimated credit losses and prepayments. At September 30, 2017 , the Company classified $29.7 million of loans held-for-investment as Level 3. The weighted average discount rate used as an input to value these loans at September 30, 2017 was 3.65% with discount rates applied ranging from 3% - 4% . The higher the rate utilized to discount estimated future cash flows, the lower the fair value measurement. As noted above, the fair value estimate also includes assumptions of prepayment speeds and credit losses. The Company included a prepayments speed assumption of 9.62% at September 30, 2017 . Prepayment speeds are inversely related to the fair value of these loans as an increase in prepayment speeds results in a decreased valuation. Additionally, the weighted average credit loss rate used as an input to value the specific loans was 0.94% with credit loss rates ranging from 0% - 3% at September 30, 2017 . Mortgage servicing rights ("MSRs") —Fair value for MSRs is determined utilizing a valuation model which calculates the fair value of each servicing rights based on the present value of estimated future cash flows. The Company uses a discount rate commensurate with the risk associated with each servicing rights, given current market conditions. At September 30, 2017 , the Company classified $29.4 million of MSRs as Level 3. The weighted average discount rate used as an input to value the MSRs at September 30, 2017 was 9.97% with discount rates applied ranging from 9% - 15% . The higher the rate utilized to discount estimated future cash flows, the lower the fair value measurement. The fair value of MSRs was also estimated based on other assumptions including prepayment speeds and the cost to service. Prepayment speeds used as an input to value the MSRs at September 30, 2017 ranged from 0% - 47% or a weighted average prepayment speed of 10.50% . Further, for current and delinquent loans, the Company assumed a weighted average cost of servicing of $69 and $634 , respectively, per loan. Prepayment speeds and the cost to service are both inversely related to the fair value of MSRs as an increase in prepayment speeds or the cost to service results in a decreased valuation. Derivative instruments —The Company’s derivative instruments include interest rate swaps and caps, commitments to fund mortgages for sale into the secondary market (interest rate locks), forward commitments to end investors for the sale of mortgage loans and foreign currency contracts. Interest rate swaps and caps are valued by a third party, using models that primarily use market observable inputs, such as yield curves, and are corroborated by comparison with valuations provided by the respective counterparties. The credit risk associated with derivative financial instruments that are subject to master netting agreements is measured on a net basis by counterparty portfolio. The fair value for mortgage-related derivatives is based on changes in mortgage rates from the date of the commitments. The fair value of foreign currency derivatives is computed based on change in foreign currency rates stated in the contract compared to those prevailing at the measurement date. At September 30, 2017 , the Company classified $1.2 million of derivative assets related to interest rate locks as Level 3. The fair value of interest rate locks is based on prices obtained for loans with similar characteristics from third parties, adjusted for the pull-through rate, which represents the Company’s best estimate of the likelihood that a committed loan will ultimately fund. The weighted-average pull-through rate at September 30, 2017 was 88.85% with pull-through rates applied ranging from 38% to 100% . Pull-through rates are directly related to the fair value of interest rate locks as an increase in the pull-through rate results in an increased valuation Nonqualified deferred compensation assets —The underlying assets relating to the nonqualified deferred compensation plan are included in a trust and primarily consist of non-exchange traded institutional funds which are priced based by an independent third party service.
Foreclosed Assets	Other real estate owned is comprised of real estate acquired in partial or full satisfaction of loans and is included in other assets. Other real estate owned is recorded at its estimated fair value less estimated selling costs at the date of transfer, with any excess of the related loan balance over the fair value less expected selling costs charged to the allowance for loan losses. Subsequent changes in value are reported as adjustments to the carrying amount and are recorded in other non-interest expense. Gains and losses upon sale, if any, are also charged to other non-interest expense. Fair value is generally based on third party appraisals and internal estimates that are adjusted by a discount representing the estimated cost of sale and is therefore considered a Level 3 valuation.
Fair Value Measurement	Also, the Company may be required, from time to time, to measure certain other financial assets at fair value on a nonrecurring basis in accordance with GAAP. These adjustments to fair value usually result from impairment charges on individual assets. The following methods and assumptions were used by the Company in estimating fair values of financial instruments that were not previously disclosed. Held-to-maturity securities. Held-to-maturity securities include U.S. Government-sponsored agency securities and municipal bonds issued by various municipal government entities primarily located in the Chicago metropolitan area and southern Wisconsin. Fair values for held-to-maturity securities are typically based on prices obtained from independent pricing vendors. In accordance with ASC 820, the Company has categorized held-to-maturity securities as a Level 2 fair value measurement. Loans held-for-investment, at amortized cost. Fair values are estimated for portfolios of loans with similar financial characteristics. Loans are analyzed by type such as commercial, residential real estate, etc. Each category is further segmented by interest rate type (fixed and variable) and term. For variable-rate loans that reprice frequently, estimated fair values are based on carrying values. The fair value of residential loans is based on secondary market sources for securities backed by similar loans, adjusted for differences in loan characteristics. The fair value for other fixed rate loans is estimated by discounting scheduled cash flows through the estimated maturity using estimated market discount rates that reflect credit and interest rate risks inherent in the loan. The primary impact of credit risk on the present value of the loan portfolio, however, was assessed through the use of the allowance for loan losses, which is believed to represent the current fair value of probable incurred losses for purposes of the fair value calculation. In accordance with ASC 820, the Company has categorized loans as a Level 3 fair value measurement. Deposits with stated maturities. The fair value of certificates of deposit is based on the discounted value of contractual cash flows. The discount rate is estimated using the rates currently in effect for deposits of similar remaining maturities. In accordance with ASC 820, the Company has categorized deposits with stated maturities as a Level 3 fair value measurement. FHLB advances. The fair value of FHLB advances is obtained from the FHLB which uses a discounted cash flow analysis based on current market rates of similar maturity debt securities to discount cash flows. In accordance with ASC 820, the Company has categorized FHLB advances as a Level 3 fair value measurement. Subordinated notes. The fair value of the subordinated notes is based on a market price obtained from an independent pricing vendor. In accordance with ASC 820, the Company has categorized subordinated notes as a Level 2 fair value measurement. Junior subordinated debentures. The fair value of the junior subordinated debentures is based on the discounted value of contractual cash flows. In accordance with ASC 820, the Company has categorized junior subordinated debentures as a Level 3 fair value measurement. The Company is required under applicable accounting guidance to report the fair value of all financial instruments on the consolidated statements of condition, including those financial instruments carried at cost.
Stock-Based Compensation	Stock-based compensation is measured as the fair value of an award on the date of grant, and the measured cost is recognized over the period which the recipient is required to provide service in exchange for the award. The fair values of restricted share and performance-based stock awards are determined based on the average of the high and low trading prices on the grant date, and the fair value of stock options is estimated using a Black-Scholes option-pricing model that utilizes the assumptions outlined in the following table. Option-pricing models require the input of highly subjective assumptions and are sensitive to changes in the option's expected life and the price volatility of the underlying stock, which can materially affect the fair value estimate. Options granted since the inception of the LTIP in 2011 were primarily granted as LTIP awards. Expected life of options granted since the inception of the LTIP awards has been based on the safe harbor rule of the SEC Staff Accounting Bulletin No. 107 “Share-Based Payment” as the Company believes historical exercise data may not provide a reasonable basis to estimate the expected term of these options. Expected stock price volatility is based on historical volatility of the Company's common stock, which correlates with the expected life of the options, and the risk-free interest rate is based on comparable U.S. Treasury rates. Management reviews and adjusts the assumptions used to calculate the fair value of an option on a periodic basis to better reflect expected trends.
Option and Incentive Plans	Stock based compensation is recognized based upon the number of awards that are ultimately expected to vest, taking into account expected forfeitures. In addition, for performance-based awards, an estimate is made of the number of shares expected to vest as a result of actual performance against the performance criteria in the award to determine the amount of compensation expense to recognize. The estimate is reevaluated periodically and total compensation expense is adjusted for any change in estimate in the current period.
Earnings Per Share	Potentially dilutive common shares can result from stock options, restricted stock unit awards, stock warrants, the Company’s convertible preferred stock and shares to be issued under the Employee Stock Purchase Plan and the Directors Deferred Fee and Stock Plan, being treated as if they had been either exercised or issued, computed by application of the treasury stock method. While potentially dilutive common shares are typically included in the computation of diluted earnings per share, potentially dilutive common shares are excluded from this computation in periods in which the effect would reduce the loss per share or increase the income per share. For diluted earnings per share, net income applicable to common shares can be affected by the conversion of the Company’s convertible preferred stock. Where the effect of this conversion would reduce the loss per share or increase the income per share for a period, net income applicable to common shares is not adjusted by the associated preferred dividends.

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Sep. 30, 2017
Business Combinations [Abstract]
Summary of FDIC Indemnification Liability	The following table summarizes the activity in the Company’s FDIC indemnification liability during the periods indicated: Three Months Ended Nine Months Ended (Dollars in thousands) September 30, September 30, September 30, September 30, Balance at beginning of period $ 15,375 $ 11,729 $ 16,701 $ 6,100 Reductions from reimbursable expenses (159 ) (21 ) (316 ) (751 ) Amortization 311 456 1,010 1,322 Changes in expected reimbursements from (to) the FDIC for changes in expected credit losses and reimbursable expenses 994 4,077 (1,665 ) 9,150 Payments (paid to) received from the FDIC (1,049 ) 1,704 (258 ) 2,124 Balance at end of period $ 15,472 $ 17,945 $ 15,472 $ 17,945

Investment Securities (Tables)

Investment Securities (Tables)	9 Months Ended
	Sep. 30, 2017
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Marketable Securities	The following tables are a summary of the available-for-sale and held-to-maturity securities portfolios as of the dates shown: September 30, 2017 (Dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities U.S. Treasury $ 144,872 $ — $ (727 ) $ 144,145 U.S. Government agencies 159,884 10 (566 ) 159,328 Municipal 113,796 2,493 (273 ) 116,016 Corporate notes: Financial issuers 60,325 63 (771 ) 59,617 Other 1,000 — (3 ) 997 Mortgage-backed: (1) Mortgage-backed securities 1,114,655 1,477 (30,436 ) 1,085,696 Collateralized mortgage obligations 63,934 230 (412 ) 63,752 Equity securities 33,166 3,867 (681 ) 36,352 Total available-for-sale securities $ 1,691,632 $ 8,140 $ (33,869 ) $ 1,665,903 Held-to-maturity securities U.S. Government agencies $ 585,061 $ 249 $ (12,579 ) $ 572,731 Municipal 234,279 2,185 (2,159 ) 234,305 Total held-to-maturity securities $ 819,340 $ 2,434 $ (14,738 ) $ 807,036 December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available-for-sale securities U.S. Treasury $ 142,741 $ 1 $ (759 ) $ 141,983 U.S. Government agencies 189,540 47 (435 ) 189,152 Municipal 129,446 2,969 (606 ) 131,809 Corporate notes: Financial issuers 65,260 132 (1,000 ) 64,392 Other 1,000 — (1 ) 999 Mortgage-backed: (1) Mortgage-backed securities 1,185,448 284 (54,330 ) 1,131,402 Collateralized mortgage obligations 30,105 67 (490 ) 29,682 Equity securities 32,608 3,429 (789 ) 35,248 Total available-for-sale securities $ 1,776,148 $ 6,929 $ (58,410 ) $ 1,724,667 Held-to-maturity securities U.S. Government agencies $ 433,343 $ 7 $ (24,470 ) $ 408,880 Municipal 202,362 647 (4,287 ) 198,722 Total held-to-maturity securities $ 635,705 $ 654 $ (28,757 ) $ 607,602 September 30, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available-for-sale securities U.S. Treasury $ 30,017 $ 19 $ — $ 30,036 U.S. Government agencies 93,561 163 (41 ) 93,683 Municipal 106,033 3,395 (147 ) 109,281 Corporate notes: Financial issuers 65,215 299 (1,311 ) 64,203 Other 1,000 — — 1,000 Mortgage-backed: (1) Mortgage-backed securities 1,257,070 7,958 (54 ) 1,264,974 Collateralized mortgage obligations 35,935 304 (102 ) 36,137 Equity securities 48,568 2,998 (784 ) 50,782 Total available-for-sale securities $ 1,637,399 $ 15,136 $ (2,439 ) $ 1,650,096 Held-to-maturity securities U.S. Government agencies $ 729,417 $ 7,577 $ (2,879 ) $ 734,115 Municipal 203,350 5,515 (314 ) 208,551 Total held-to-maturity securities $ 932,767 $ 13,092 $ (3,193 ) $ 942,666 (1) Consisting entirely of residential mortgage-backed securities, none of which are subprime.
Investment Securities, Continuous Unrealized Loss Position, Fair Value	The following table presents the portion of the Company’s available-for-sale and held-to-maturity securities portfolios which has gross unrealized losses, reflecting the length of time that individual securities have been in a continuous unrealized loss position at September 30, 2017 : Continuous unrealized losses existing for less than 12 months Continuous unrealized losses existing for greater than 12 months Total (Dollars in thousands) Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale securities U.S. Treasury $ 144,144 $ (727 ) $ — $ — $ 144,144 $ (727 ) U.S. Government agencies 112,268 (451 ) 41,980 (115 ) 154,248 (566 ) Municipal 24,117 (138 ) 10,725 (135 ) 34,842 (273 ) Corporate notes: Financial issuers — — 35,194 (771 ) 35,194 (771 ) Other — — 997 (3 ) 997 (3 ) Mortgage-backed: Mortgage-backed securities 51,035 (6,629 ) 798,152 (23,807 ) 849,187 (30,436 ) Collateralized mortgage obligations 25,685 (195 ) 7,216 (217 ) 32,901 (412 ) Equity securities 9,177 (283 ) 6,102 (398 ) 15,279 (681 ) Total available-for-sale securities $ 366,426 $ (8,423 ) $ 900,366 $ (25,446 ) $ 1,266,792 $ (33,869 ) Held-to-maturity securities U.S. Government agencies $ 400,980 $ (12,579 ) $ — $ — $ 400,980 $ (12,579 ) Municipal 115,384 (2,159 ) — — 115,384 (2,159 ) Total held-to-maturity securities $ 516,364 $ (14,738 ) $ — $ — $ 516,364 $ (14,738 )
Schedule of Realized Gain (Loss)	The following table provides information as to the amount of gross gains and gross losses realized and proceeds received through the sale or call of investment securities: Three months ended September 30, Nine months ended September 30, (Dollars in thousands) 2017 2016 2017 2016 Realized gains $ 58 $ 3,429 $ 106 $ 7,466 Realized losses (19 ) (124 ) (75 ) (1,396 ) Net realized gains $ 39 $ 3,305 $ 31 $ 6,070 Other than temporary impairment charges — — — — Gains on investment securities, net $ 39 $ 3,305 $ 31 $ 6,070 Proceeds from sales and calls of available-for-sale securities $ 136,789 $ 1,114,666 $ 146,518 $ 2,186,662 Proceeds from calls of held-to-maturity securities 17 141,885 51,079 423,866
Investments Classified by Contractual Maturity Date	The amortized cost and fair value of securities as of September 30, 2017 , December 31, 2016 and September 30, 2016 , by contractual maturity, are shown in the following table. Contractual maturities may differ from actual maturities as borrowers may have the right to call or repay obligations with or without call or prepayment penalties. Mortgage-backed securities determined to be available-for-sale are not included in the maturity categories in the following maturity summary as actual maturities may differ from contractual maturities because the underlying mortgages may be called or prepaid without penalties: September 30, 2017 December 31, 2016 September 30, 2016 (Dollars in thousands) Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Available-for-sale securities Due in one year or less $ 150,907 $ 150,241 $ 145,353 $ 145,062 $ 115,227 $ 115,487 Due in one to five years 282,443 282,121 321,019 320,423 141,364 141,368 Due in five to ten years 38,339 39,458 27,319 28,451 28,696 31,319 Due after ten years 8,188 8,283 34,296 34,399 10,539 10,029 Mortgage-backed 1,178,589 1,149,448 1,215,553 1,161,084 1,293,005 1,301,111 Equity securities 33,166 36,352 32,608 35,248 48,568 50,782 Total available-for-sale securities $ 1,691,632 $ 1,665,903 $ 1,776,148 $ 1,724,667 $ 1,637,399 $ 1,650,096 Held-to-maturity securities Due in one year or less $ 170 $ 171 $ — $ — $ — $ — Due in one to five years 36,914 36,734 29,794 29,416 25,927 26,023 Due in five to ten years 193,387 192,581 69,664 67,820 64,835 65,842 Due after ten years 588,869 577,550 536,247 510,366 842,005 850,801 Total held-to-maturity securities $ 819,340 $ 807,036 $ 635,705 $ 607,602 $ 932,767 $ 942,666

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2017
Loans and Leases Receivable Disclosure [Abstract]
Summary of Loan Portfolio	The following table shows the Company’s loan portfolio by category as of the dates shown: September 30, December 31, September 30, (Dollars in thousands) 2017 2016 2016 Balance: Commercial $ 6,456,034 $ 6,005,422 $ 5,951,544 Commercial real estate 6,400,781 6,196,087 5,908,684 Home equity 672,969 725,793 742,868 Residential real estate 789,499 705,221 663,598 Premium finance receivables—commercial 2,664,912 2,478,581 2,430,233 Premium finance receivables—life insurance 3,795,474 3,470,027 3,283,359 Consumer and other 133,112 122,041 120,975 Total loans, net of unearned income, excluding covered loans $ 20,912,781 $ 19,703,172 $ 19,101,261 Covered loans 46,601 58,145 95,940 Total loans $ 20,959,382 $ 19,761,317 $ 19,197,201 Mix: Commercial 31 % 30 % 31 % Commercial real estate 31 31 31 Home equity 3 4 4 Residential real estate 3 4 3 Premium finance receivables—commercial 13 12 13 Premium finance receivables—life insurance 18 18 17 Consumer and other 1 1 1 Total loans, net of unearned income, excluding covered loans 100 % 100 % 100 % Covered loans — — — Total loans 100 % 100 % 100 %
Schedule of Unpaid Principal Balance and Carrying Value of Acquired Loans	The following table presents the unpaid principal balance and carrying value for these acquired loans: September 30, 2017 December 31, 2016 (Dollars in thousands) Unpaid Principal Balance Carrying Value Unpaid Carrying PCI loans $ 406,891 $ 379,407 $ 509,446 $ 471,786
Activity Related to Accretable Yield of Loans Acquired With Evidence of Credit Quality Deterioratio Since Origination	The following table provides activity for the accretable yield of PCI loans: Three Months Ended Nine Months Ended (Dollars in thousands) September 30, September 30, September 30, September 30, Accretable yield, beginning balance $ 45,510 $ 55,630 $ 49,408 $ 63,902 Acquisitions — — 426 1,082 Accretable yield amortized to interest income (5,025 ) (6,449 ) (16,101 ) (17,105 ) Accretable yield amortized to indemnification asset/liability (1) (371 ) (1,744 ) (1,086 ) (5,539 ) Reclassification from non-accretable difference (2) 1,017 5,370 7,106 12,099 Decreases in interest cash flows due to payments and changes in interest rates (875 ) 170 503 (1,462 ) Accretable yield, ending balance (3) $ 40,256 $ 52,977 $ 40,256 $ 52,977 (1) Represents the portion of the current period accreted yield, resulting from lower expected losses, applied to reduce the loss share indemnification asset or increase the loss share indemnification liability. (2) Reclassification is the result of subsequent increases in expected principal cash flows. (3) As of September 30, 2017 , the Company estimates that the remaining accretable yield balance to be amortized to the indemnification asset or liability for the bank acquisitions is approximately $24,000 . The remainder of the accretable yield related to bank acquisitions is expected to be amortized to interest income.

Allowance for Loan Losses, Al29

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Tables)	9 Months Ended
	Sep. 30, 2017
Receivables [Abstract]
Schedule of Aging of the Company's Loan Portfolio	The tables below show the aging of the Company’s loan portfolio at September 30, 2017 , December 31, 2016 and September 30, 2016 : As of September 30, 2017 90+ days and still accruing 60-89 days past due 30-59 days past due (Dollars in thousands) Nonaccrual Current Total Loans Loan Balances: Commercial Commercial, industrial and other $ 12,281 $ — $ 3,161 $ 13,710 $ 4,091,381 $ 4,120,533 Franchise — — — 16,719 836,997 853,716 Mortgage warehouse lines of credit — — — 312 194,058 194,370 Asset-based lending 1,141 — 1,533 4,515 889,147 896,336 Leases 509 — 281 1,194 379,410 381,394 PCI - commercial (1) — 1,489 61 — 8,135 9,685 Total commercial 13,931 1,489 5,036 36,450 6,399,128 6,456,034 Commercial real estate: Construction 1,607 — 366 2,064 669,940 673,977 Land 196 — — — 102,557 102,753 Office 5,148 — — 1,220 874,583 880,951 Industrial 1,848 — 137 438 834,062 836,485 Retail 2,200 — 3,030 3,674 925,335 934,239 Multi-family 569 — 68 3,058 861,290 864,985 Mixed use and other 3,310 — 843 3,561 1,966,601 1,974,315 PCI - commercial real estate (1) — 8,443 1,394 2,940 120,299 133,076 Total commercial real estate 14,878 8,443 5,838 16,955 6,354,667 6,400,781 Home equity 7,581 — 446 2,590 662,352 672,969 Residential real estate, including PCI 14,743 1,120 2,055 165 771,416 789,499 Premium finance receivables Commercial insurance loans 9,827 9,584 7,421 9,966 2,628,114 2,664,912 Life insurance loans — 6,740 946 6,937 3,571,388 3,586,011 PCI - life insurance loans (1) — — — — 209,463 209,463 Consumer and other, including PCI 540 221 242 685 131,424 133,112 Total loans, net of unearned income, excluding covered loans $ 61,500 $ 27,597 $ 21,984 $ 73,748 $ 20,727,952 $ 20,912,781 Covered loans 1,936 2,233 1,074 45 41,313 46,601 Total loans, net of unearned income $ 63,436 $ 29,830 $ 23,058 $ 73,793 $ 20,769,265 $ 20,959,382 (1) PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. Loan agings are based upon contractually required payments. As of December 31, 2016 90+ days and still accruing 60-89 days past due 30-59 days past due (Dollars in thousands) Nonaccrual Current Total Loans Loan Balances: Commercial Commercial, industrial and other $ 13,441 $ 174 $ 2,341 $ 11,779 $ 3,716,977 $ 3,744,712 Franchise — — — 493 869,228 869,721 Mortgage warehouse lines of credit — — — — 204,225 204,225 Asset-based lending 1,924 — 135 1,609 871,402 875,070 Leases 510 — — 1,331 293,073 294,914 PCI - commercial (1) — 1,689 100 2,428 12,563 16,780 Total commercial 15,875 1,863 2,576 17,640 5,967,468 6,005,422 Commercial real estate Construction 2,408 — — 1,824 606,007 610,239 Land 394 — 188 — 104,219 104,801 Office 4,337 — 4,506 1,232 857,599 867,674 Industrial 7,047 — 4,516 2,436 756,602 770,601 Retail 597 — 760 3,364 907,872 912,593 Multi-family 643 — 322 1,347 805,312 807,624 Mixed use and other 6,498 — 1,186 12,632 1,931,859 1,952,175 PCI - commercial real estate (1) — 16,188 3,775 8,888 141,529 170,380 Total commercial real estate 21,924 16,188 15,253 31,723 6,110,999 6,196,087 Home equity 9,761 — 1,630 6,515 707,887 725,793 Residential real estate, including PCI 12,749 1,309 936 8,271 681,956 705,221 Premium finance receivables Commercial insurance loans 14,709 7,962 5,646 14,580 2,435,684 2,478,581 Life insurance loans — 3,717 17,514 16,204 3,182,935 3,220,370 PCI - life insurance loans (1) — — — — 249,657 249,657 Consumer and other, including PCI 439 207 100 887 120,408 122,041 Total loans, net of unearned income, excluding covered loans $ 75,457 $ 31,246 $ 43,655 $ 95,820 $ 19,456,994 $ 19,703,172 Covered loans 2,121 2,492 225 1,553 51,754 58,145 Total loans, net of unearned income $ 77,578 $ 33,738 $ 43,880 $ 97,373 $ 19,508,748 $ 19,761,317 As of September 30, 2016 90+ days and still accruing 60-89 days past due 30-59 days past due (Dollars in thousands) Nonaccrual Current Total Loans Loan Balances: Commercial Commercial, industrial and other $ 15,809 $ — $ 7,324 $ 8,987 $ 3,573,396 $ 3,605,516 Franchise — — 458 1,626 872,661 874,745 Mortgage warehouse lines of credit — — — — 309,632 309,632 Asset-based lending 234 — 3,772 3,741 837,972 845,719 Leases 375 — 239 — 299,339 299,953 PCI - commercial (1) — 1,783 — 1,036 13,160 15,979 Total commercial 16,418 1,783 11,793 15,390 5,906,160 5,951,544 Commercial real estate: Construction 400 — — 3,775 447,302 451,477 Land 1,208 — 787 300 105,406 107,701 Office 3,609 — 6,457 8,062 865,954 884,082 Industrial 9,967 — 940 2,961 753,636 767,504 Retail 909 — 1,340 8,723 884,369 895,341 Multi-family 90 — 3,051 2,169 789,645 794,955 Mixed use and other 6,442 — 2,157 5,184 1,837,724 1,851,507 PCI - commercial real estate (1) — 21,433 1,509 4,066 129,109 156,117 Total commercial real estate 22,625 21,433 16,241 35,240 5,813,145 5,908,684 Home equity 9,309 — 1,728 3,842 727,989 742,868 Residential real estate, including PCI 12,205 1,496 2,232 1,088 646,577 663,598 Premium finance receivables Commercial insurance loans 14,214 7,754 6,968 10,291 2,391,006 2,430,233 Life insurance loans — — 9,960 3,717 3,006,795 3,020,472 PCI - life insurance loans (1) — — — — 262,887 262,887 Consumer and other, including PCI 543 124 204 871 119,233 120,975 Total loans, net of unearned income, excluding covered loans $ 75,314 $ 32,590 $ 49,126 $ 70,439 $ 18,873,792 $ 19,101,261 Covered loans 2,331 4,806 1,545 2,456 84,802 95,940 Total loans, net of unearned income $ 77,645 $ 37,396 $ 50,671 $ 72,895 $ 18,958,594 $ 19,197,201 (1) PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. Loan agings are based upon contractually required payments.
Summary of Performance by Loan Class	The following table presents the recorded investment based on performance of loans by class, excluding covered loans, per the most recent analysis at September 30, 2017 , December 31, 2016 and September 30, 2016 : Performing Non-performing Total (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, September 30, December 31, September 30, Loan Balances: Commercial Commercial, industrial and other $ 4,108,252 $ 3,731,097 $ 3,589,707 $ 12,281 $ 13,615 $ 15,809 $ 4,120,533 $ 3,744,712 $ 3,605,516 Franchise 853,716 869,721 874,745 — — — 853,716 869,721 874,745 Mortgage warehouse lines of credit 194,370 204,225 309,632 — — — 194,370 204,225 309,632 Asset-based lending 895,195 873,146 845,485 1,141 1,924 234 896,336 875,070 845,719 Leases 380,885 294,404 299,578 509 510 375 381,394 294,914 299,953 PCI - commercial (1) 9,685 16,780 15,979 — — — 9,685 16,780 15,979 Total commercial 6,442,103 5,989,373 5,935,126 13,931 16,049 16,418 6,456,034 6,005,422 5,951,544 Commercial real estate Construction 672,370 607,831 451,077 1,607 2,408 400 673,977 610,239 451,477 Land 102,557 104,407 106,493 196 394 1,208 102,753 104,801 107,701 Office 875,803 863,337 880,473 5,148 4,337 3,609 880,951 867,674 884,082 Industrial 834,637 763,554 757,537 1,848 7,047 9,967 836,485 770,601 767,504 Retail 932,039 911,996 894,432 2,200 597 909 934,239 912,593 895,341 Multi-family 864,416 806,981 794,865 569 643 90 864,985 807,624 794,955 Mixed use and other 1,971,005 1,945,677 1,845,065 3,310 6,498 6,442 1,974,315 1,952,175 1,851,507 PCI - commercial real estate (1) 133,076 170,380 156,117 — — — 133,076 170,380 156,117 Total commercial real estate 6,385,903 6,174,163 5,886,059 14,878 21,924 22,625 6,400,781 6,196,087 5,908,684 Home equity 665,388 716,032 733,559 7,581 9,761 9,309 672,969 725,793 742,868 Residential real estate, including PCI 774,756 692,472 651,393 14,743 12,749 12,205 789,499 705,221 663,598 Premium finance receivables Commercial insurance loans 2,645,501 2,455,910 2,408,265 19,411 22,671 21,968 2,664,912 2,478,581 2,430,233 Life insurance loans 3,579,271 3,216,653 3,020,472 6,740 3,717 — 3,586,011 3,220,370 3,020,472 PCI - life insurance loans (1) 209,463 249,657 262,887 — — — 209,463 249,657 262,887 Consumer and other, including PCI 132,413 121,458 120,372 699 583 603 133,112 122,041 120,975 Total loans, net of unearned income, excluding covered loans $ 20,834,798 $ 19,615,718 $ 19,018,133 $ 77,983 $ 87,454 $ 83,128 $ 20,912,781 $ 19,703,172 $ 19,101,261 (1) PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. See Note 6 - Loans for further discussion of these purchased loans.
Summary of Activity in the Allowance for Credit Losses	A summary of activity in the allowance for credit losses by loan portfolio (excluding covered loans) for the three and nine months ended September 30, 2017 and 2016 is as follows: Three months ended September 30, 2017 Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivables Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Commercial Allowance for credit losses Allowance for loan losses at beginning of period $ 52,358 $ 52,339 $ 11,134 $ 6,143 $ 6,352 $ 1,265 $ 129,591 Other adjustments (2 ) (38 ) — (31 ) 32 — (39 ) Reclassification from allowance for unfunded lending-related commitments 500 (406 ) — — — — 94 Charge-offs (2,265 ) (989 ) (968 ) (267 ) (1,716 ) (213 ) (6,418 ) Recoveries 801 323 178 55 499 93 1,949 Provision for credit losses 4,343 811 212 757 1,386 433 7,942 Allowance for loan losses at period end $ 55,735 $ 52,040 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 133,119 Allowance for unfunded lending-related commitments at period end $ — $ 1,276 $ — $ — $ — $ — $ 1,276 Allowance for credit losses at period end $ 55,735 $ 53,316 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 134,395 Individually evaluated for impairment $ 4,568 $ 1,184 $ 691 $ 758 $ — $ 34 $ 7,235 Collectively evaluated for impairment 50,623 52,048 9,865 5,813 6,553 1,544 126,446 Loans acquired with deteriorated credit quality 544 84 — 86 — — 714 Loans at period end Individually evaluated for impairment $ 18,086 $ 31,698 $ 7,729 $ 21,263 $ — $ 544 $ 79,320 Collectively evaluated for impairment 6,428,263 6,236,007 665,240 735,185 6,250,923 131,581 20,447,199 Loans acquired with deteriorated credit quality 9,685 133,076 — 3,637 209,463 987 356,848 Loans held at fair value — — — 29,414 — — 29,414 Three months ended September 30, 2016 Commercial Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivables Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Allowance for credit losses Allowance for loan losses at beginning of period $ 41,654 $ 46,824 $ 11,383 $ 5,405 $ 7,814 $ 1,276 $ 114,356 Other adjustments (35 ) (57 ) — (10 ) (10 ) — (112 ) Reclassification from allowance for unfunded lending-related commitments (500 ) (79 ) — — — — (579 ) Charge-offs (3,469 ) (382 ) (574 ) (134 ) (1,959 ) (389 ) (6,907 ) Recoveries 176 364 65 61 456 72 1,194 Provision for credit losses 5,212 1,678 810 781 974 286 9,741 Allowance for loan losses at period end $ 43,038 $ 48,348 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 117,693 Allowance for unfunded lending-related commitments at period end $ 500 $ 1,148 $ — $ — $ — $ — $ 1,648 Allowance for credit losses at period end $ 43,538 $ 49,496 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 119,341 Individually evaluated for impairment $ 2,554 $ 2,491 $ 964 $ 1,166 $ — $ 192 $ 7,367 Collectively evaluated for impairment 40,252 46,983 10,720 4,867 7,275 1,053 111,150 Loans acquired with deteriorated credit quality 732 22 — 70 — — 824 Loans at period end Individually evaluated for impairment $ 19,133 $ 45,290 $ 9,309 $ 17,040 $ — $ 602 $ 91,374 Collectively evaluated for impairment 5,916,432 5,707,277 733,559 625,030 5,450,705 119,162 18,552,165 Loans acquired with deteriorated credit quality 15,979 156,117 — 3,925 262,887 1,211 440,119 Loans held at fair value — — — 17,603 — — 17,603 Nine months ended September 30, 2017 Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivable Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Commercial Allowance for credit losses Allowance for loan losses at beginning of period $ 44,493 $ 51,422 $ 11,774 $ 5,714 $ 7,625 $ 1,263 $ 122,291 Other adjustments (23 ) (121 ) — (38 ) 57 — (125 ) Reclassification from allowance for unfunded lending-related commitments 500 (438 ) — — — — 62 Charge-offs (3,819 ) (3,235 ) (3,224 ) (742 ) (5,021 ) (522 ) (16,563 ) Recoveries 1,635 1,153 387 287 1,515 267 5,244 Provision for credit losses 12,949 3,259 1,619 1,436 2,377 570 22,210 Allowance for loan losses at period end $ 55,735 $ 52,040 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 133,119 Allowance for unfunded lending-related commitments at period end $ — $ 1,276 $ — $ — $ — $ — $ 1,276 Allowance for credit losses at period end $ 55,735 $ 53,316 $ 10,556 $ 6,657 $ 6,553 $ 1,578 $ 134,395 Nine months ended September 30, 2016 Commercial Real Estate Home Equity Residential Real Estate Premium Finance Receivable Consumer and Other Total, Excluding Covered Loans (Dollars in thousands) Commercial Allowance for credit losses Allowance for loan losses at beginning of period $ 36,135 $ 43,758 $ 12,012 $ 4,734 $ 7,233 $ 1,528 $ 105,400 Other adjustments (103 ) (203 ) — (49 ) 31 — (324 ) Reclassification from allowance for unfunded lending-related commitments (500 ) (200 ) — — — — (700 ) Charge-offs (4,861 ) (1,555 ) (3,672 ) (1,320 ) (6,350 ) (720 ) (18,478 ) Recoveries 926 1,029 184 204 1,876 143 4,362 Provision for credit losses 11,441 5,519 3,160 2,534 4,485 294 27,433 Allowance for loan losses at period end $ 43,038 $ 48,348 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 117,693 Allowance for unfunded lending-related commitments at period end $ 500 $ 1,148 $ — $ — $ — $ — $ 1,648 Allowance for credit losses at period end $ 43,538 $ 49,496 $ 11,684 $ 6,103 $ 7,275 $ 1,245 $ 119,341
Summary Of Activity In Allowance For Covered Loan By FDIC Loss Table	A summary of activity in the allowance for covered loan losses for the three and nine months ended September 30, 2017 and 2016 is as follows: Three Months Ended Nine Months Ended September 30, September 30, September 30, September 30, (Dollars in thousands) 2017 2016 2017 2016 Balance at beginning of period $ 1,074 $ 2,412 $ 1,322 $ 3,026 Provision for covered loan losses before benefit attributable to FDIC loss share agreements (225 ) (847 ) (1,063 ) (3,495 ) Benefit attributable to FDIC loss share agreements 180 677 850 2,796 Net provision for covered loan losses (45 ) (170 ) (213 ) (699 ) Increase in FDIC indemnification liability (180 ) (677 ) (850 ) (2,796 ) Loans charged-off (155 ) (918 ) (491 ) (1,291 ) Recoveries of loans charged-off 64 775 990 3,182 Net (charge-offs) recoveries (91 ) (143 ) 499 1,891 Balance at end of period $ 758 $ 1,422 $ 758 $ 1,422
Summary of Impaired Loans, Including Restructured Loans	A summary of impaired loans, including troubled debt restructurings ("TDRs"), is as follows: September 30, December 31, September 30, (Dollars in thousands) 2017 2016 2016 Impaired loans (included in non-performing and TDRs): Impaired loans with an allowance for loan loss required (1) $ 30,864 $ 33,146 $ 39,022 Impaired loans with no allowance for loan loss required 47,730 57,370 51,518 Total impaired loans (2) $ 78,594 $ 90,516 $ 90,540 Allowance for loan losses related to impaired loans $ 7,218 $ 6,377 $ 6,836 TDRs $ 33,183 $ 41,708 $ 44,276 (1) These impaired loans require an allowance for loan losses because the estimated fair value of the loans or related collateral is less than the recorded investment in the loans. (2) Impaired loans are considered by the Company to be non-accrual loans, TDRs or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest.
Summary of Impaired Loans by Loan Class	The following tables present impaired loans by loan class, excluding covered loans, for the periods ended as follows: For the Nine Months Ended As of September 30, 2017 September 30, 2017 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with a related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 7,312 $ 8,458 $ 4,191 $ 8,390 $ 407 Asset-based lending 588 589 161 588 21 Leases 2,440 2,444 215 2,539 91 Commercial real estate Construction 1,607 2,408 94 2,319 93 Land — — — — — Office 2,225 2,291 570 2,280 94 Industrial 408 408 75 415 19 Retail 5,932 6,072 158 5,998 191 Multi-family 1,239 1,239 8 1,250 33 Mixed use and other 1,537 1,695 263 1,580 60 Home equity 1,511 1,721 691 1,528 53 Residential real estate 5,842 6,154 758 5,842 177 Consumer and other 223 224 34 225 10 Impaired loans with no related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 5,995 $ 7,260 $ — $ 6,662 $ 294 Asset-based lending 553 553 — 728 31 Leases 817 817 — 862 38 Commercial real estate Construction 1,504 1,504 — 1,524 49 Land 3,968 4,217 — 4,110 136 Office 3,400 3,585 — 3,565 147 Industrial 1,440 2,729 — 2,885 183 Retail 1,978 1,988 — 2,008 103 Multi-family 569 653 — 571 23 Mixed use and other 5,546 6,267 — 5,745 241 Home equity 6,218 9,523 — 7,231 339 Residential real estate 15,421 17,859 — 15,726 575 Consumer and other 321 433 — 334 16 Total impaired loans, net of unearned income $ 78,594 $ 91,091 $ 7,218 $ 84,905 $ 3,424 For the Twelve Months Ended As of December 31, 2016 December 31, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with a related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 2,601 $ 2,617 $ 1,079 $ 2,649 $ 134 Asset-based lending 233 235 26 235 10 Leases 2,441 2,443 107 2,561 128 Commercial real estate Construction 5,302 5,302 86 5,368 164 Land 1,283 1,283 1 1,303 47 Office 2,687 2,697 324 2,797 137 Industrial 5,207 5,843 1,810 7,804 421 Retail 1,750 1,834 170 2,039 101 Multi-family — — — — — Mixed use and other 3,812 4,010 592 4,038 195 Home equity 1,961 1,873 1,233 1,969 75 Residential real estate 5,752 6,327 849 5,816 261 Consumer and other 117 121 100 131 7 Impaired loans with no related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 12,534 $ 14,704 $ — $ 14,944 $ 948 Asset-based lending 1,691 2,550 — 8,467 377 Leases 873 873 — 939 56 Commercial real estate Construction 4,003 4,003 — 4,161 81 Land 3,034 3,503 — 3,371 142 Office 3,994 5,921 — 4,002 323 Industrial 2,129 2,436 — 2,828 274 Retail — — — — — Multi-family 1,903 1,987 — 1,825 84 Mixed use and other 6,815 7,388 — 6,912 397 Home equity 8,033 10,483 — 8,830 475 Residential real estate 11,983 14,124 — 12,041 622 Consumer and other 378 489 — 393 26 Total impaired loans, net of unearned income $ 90,516 $ 103,046 $ 6,377 $ 105,423 $ 5,485 For the Nine Months Ended As of September 30, 2016 September 30, 2016 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized (Dollars in thousands) Impaired loans with a related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 5,426 $ 5,434 $ 1,887 $ 5,487 $ 212 Asset-based lending 234 235 44 235 7 Leases 375 375 116 388 14 Commercial real estate Construction — — — — — Land 2,620 2,620 44 2,670 80 Office 1,697 2,361 182 1,722 79 Industrial 6,855 7,338 1,388 7,069 284 Retail 6,605 6,623 240 6,668 160 Multi-family 1,266 1,266 8 1,134 29 Mixed use and other 5,437 5,511 605 5,452 198 Home equity 2,373 2,457 964 2,404 63 Residential real estate 5,942 6,428 1,166 5,807 190 Consumer and other 192 192 192 194 8 Impaired loans with no related ASC 310 allowance recorded Commercial Commercial, industrial and other $ 12,669 $ 16,261 $ — $ 14,745 $ 717 Asset-based lending — — — — — Leases — — — — — Commercial real estate Construction 1,995 1,995 — 2,273 94 Land 3,864 8,088 — 4,316 408 Office 4,980 6,243 — 4,978 260 Industrial 3,508 3,827 — 3,574 200 Retail 805 913 — 936 36 Multi-family 89 174 — 109 5 Mixed use and other 5,164 5,712 — 5,300 236 Home equity 6,936 9,108 — 7,736 320 Residential real estate 11,098 13,077 — 11,125 445 Consumer and other 410 520 — 428 21 Total impaired loans, net of unearned income $ 90,540 $ 106,758 $ 6,836 $ 94,750 $ 4,066
Summary of the Post-Modification Balance of TDRs	Nine months ended Total (1)(2) Extension at (2) Reduction of Interest (2) Modification to (2) Forgiveness of Debt (2) Count Balance Count Balance Count Balance Count Balance Count Balance Commercial Commercial, industrial and other 4 $ 1,503 1 $ 95 — $ — 3 $ 1,408 — $ — Commercial real estate Office — — — — — — — — — — Industrial — — — — — — — — — — Mixed use and other 1 1,245 1 1,245 — — — — — — Residential real estate and other 8 2,638 7 2,569 7 2,589 — — 1 69 Total loans 13 $ 5,386 9 $ 3,909 7 $ 2,589 3 $ 1,408 1 $ 69 (1) TDRs may have more than one modification representing a concession. As such, TDRs during the period may be represented in more than one of the categories noted above. (2) Balances represent the recorded investment in the loan at the time of the restructuring. Nine months ended Total (1)(2) Extension at (2) Reduction of Interest (2) Modification to (2) Forgiveness of Debt (2) Count Balance Count Balance Count Balance Count Balance Count Balance Commercial Commercial, industrial and other 3 $ 345 3 $ 345 — $ — — $ — 1 $ 275 Commercial real estate Office 1 450 1 450 — — — — — — Industrial 6 7,921 6 7,921 3 7,196 — — — — Mixed use and other 2 150 2 150 — — — — — — Residential real estate and other 3 583 2 423 3 583 1 380 — — Total loans 15 $ 9,449 14 $ 9,289 6 $ 7,779 1 $ 380 1 $ 275 (1) TDRs may have more than one modification representing a concession. As such, TDRs during the period may be represented in more than one of the categories noted above. (2) Balances represent the recorded investment in the loan at the time of the restructuring. The tables below present a summary of the post-modification balance of loans restructured during the three and nine months ended September 30, 2017 and 2016 , respectively, which represent TDRs: Three months ended September 30, 2017 (Dollars in thousands) Total (1)(2) Extension at Below Market (2) Reduction of Interest Rate (2) Modification to Interest-only Payments (2) Forgiveness of Debt (2) Count Balance Count Balance Count Balance Count Balance Count Balance Commercial Commercial, industrial and other 3 $ 1,408 — $ — — $ — 3 $ 1,408 — $ — Commercial real estate Office — — — — — — — — — — Industrial — — — — — — — — — — Mixed use and other — — — — — — — — — — Residential real estate and other 2 255 1 186 2 255 — — 1 69 Total loans 5 $ 1,663 1 $ 186 2 $ 255 3 $ 1,408 1 $ 69 Three months ended September 30, 2016 (Dollars in thousands) Total (1)(2) Extension at Below Market Terms (2) Reduction of Interest Rate (2) Modification to Interest-only Payments (2) Forgiveness of Debt (2) Count Balance Count Balance Count Balance Count Balance Count Balance Commercial Commercial, industrial and other 1 $ 28 1 $ 28 — $ — — $ — — $ — Commercial real estate Office — — — — — — — — — — Industrial — — — — — — — — — — Mixed use and other — — — — — — — — — — Residential real estate and other 1 43 1 43 1 43 — — — — Total loans 2 $ 71 2 $ 71 1 $ 43 — $ — — $ — (1) TDRs may have more than one modification representing a concession. As such, TDRs during the period may be represented in more than one of the categories noted above. (2) Balances represent the recorded investment in the loan at the time of the restructuring.
Summary of TDRs Subsequent Default Under the Restructured Terms	The following table presents a summary of all loans restructured in TDRs during the twelve months ended September 30, 2017 and 2016 , and such loans which were in payment default under the restructured terms during the respective periods below: (Dollars in thousands) As of September 30, 2017 Three Months Ended September 30, 2017 Nine Months Ended September 30, 2017 Total (1)(3) Payments in Default (2)(3) Payments in Default (2)(3) Count Balance Count Balance Count Balance Commercial Commercial, industrial and other 4 $ 1,503 — $ — — $ — Leases 2 2,949 — — — — Commercial real estate Office — — — — — — Industrial — — — — — — Mixed use and other 1 1,245 1 1,245 1 1,245 Residential real estate and other 12 3,137 1 52 2 284 Total loans 19 $ 8,834 2 $ 1,297 3 $ 1,529 (Dollars in thousands) As of September 30, 2016 Three Months Ended Nine Months Ended Total (1)(3) Payments in Default (2)(3) Payments in Default (2)(3) Count Balance Count Balance Count Balance Commercial Commercial, industrial and other 3 $ 345 — $ — — $ — Leases — — — — — — Commercial real estate Office 1 450 1 450 1 450 Industrial 6 7,921 3 725 3 725 Mixed use and other 4 351 1 16 3 217 Residential real estate and other 3 583 — — — — Total loans 17 $ 9,650 5 $ 1,191 7 $ 1,392 (1) Total TDRs represent all loans restructured in TDRs during the previous twelve months from the date indicated. (2) TDRs considered to be in payment default are over 30 days past-due subsequent to the restructuring. (3) Balances represent the recorded investment in the loan at the time of the restructuring.

Goodwill and Other Intangible30

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill Assets by Business Segment	A summary of the Company’s goodwill assets by business segment is presented in the following table: (Dollars in thousands) January 1, 2017 Goodwill Acquired Impairment Loss Goodwill Adjustments September 30, Community banking $ 427,781 $ 999 $ — $ 685 $ 429,465 Specialty finance 38,692 — — 1,750 40,442 Wealth management 32,114 — — — 32,114 Total $ 498,587 $ 999 $ — $ 2,435 $ 502,021
Summary of Finite-Lived Intangible Assets	A summary of finite-lived intangible assets as of the dates shown and the expected amortization as of September 30, 2017 is as follows: (Dollars in thousands) September 30, December 31, September 30, Community banking segment: Core deposit intangibles: Gross carrying amount $ 37,272 $ 37,272 $ 34,998 Accumulated amortization (24,550 ) (21,614 ) (20,598 ) Net carrying amount $ 12,722 $ 15,658 $ 14,400 Specialty finance segment: Customer list intangibles: Gross carrying amount $ 1,972 $ 1,800 $ 1,800 Accumulated amortization (1,258 ) (1,159 ) (1,129 ) Net carrying amount $ 714 $ 641 $ 671 Wealth management segment: Customer list and other intangibles: Gross carrying amount $ 7,940 $ 7,940 $ 7,940 Accumulated amortization (2,725 ) (2,388 ) (2,275 ) Net carrying amount $ 5,215 $ 5,552 $ 5,665 Total other intangible assets, net $ 18,651 $ 21,851 $ 20,736
Estimated Amortization	Estimated amortization Actual in nine months ended September 30, 2017 $ 3,373 Estimated remaining in 2017 1,027 Estimated—2018 3,796 Estimated—2019 3,223 Estimated—2020 2,597 Estimated—2021 2,056

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2017
Deposits [Abstract]
Summary of Deposits	The following table is a summary of deposits as of the dates shown: (Dollars in thousands) September 30, December 31, September 30, Balance: Non-interest bearing $ 6,502,409 $ 5,927,377 $ 5,711,042 NOW and interest bearing demand deposits 2,273,025 2,624,442 2,552,611 Wealth management deposits 2,171,758 2,209,617 2,283,233 Money market 4,607,995 4,441,811 4,421,631 Savings 2,673,201 2,180,482 1,977,661 Time certificates of deposit 4,666,675 4,274,903 4,201,477 Total deposits $ 22,895,063 $ 21,658,632 $ 21,147,655 Mix: Non-interest bearing 28 % 27 % 27 % NOW and interest bearing demand deposits 10 12 12 Wealth management deposits 10 10 11 Money market 20 21 21 Savings 12 10 9 Time certificates of deposit 20 20 20 Total deposits 100 % 100 % 100 %

Federal Home Loan Bank Advances

Federal Home Loan Bank Advances, Other Borrowings and Subordinated Notes (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Summary of Debt	The following table is a summary of FHLB advances, other borrowings and subordinated notes as of the dates shown: (Dollars in thousands) September 30, December 31, September 30, FHLB advances $ 468,962 $ 153,831 $ 419,632 Other borrowings: Notes payable 41,216 52,445 56,191 Short-term borrowings 19,959 61,809 33,173 Other 49,502 18,154 18,360 Secured borrowings 141,003 130,078 133,642 Total other borrowings 251,680 262,486 241,366 Subordinated notes 139,052 138,971 138,943 Total FHLB advances, other borrowings and subordinated notes $ 859,694 $ 555,288 $ 799,941
Summary of Pledged Securities Related to Securities Sold Under Repurchase Agreements	The following is a summary of these securities pledged as of September 30, 2017 disaggregated by investment category and maturity of the related customer sweep account, and reconciled to the outstanding balance of securities sold under repurchase agreements: (Dollars in thousands) Overnight Sweep Collateral Available-for-sale securities pledged U.S. Treasury $ 24,830 Mortgage-backed securities 10,162 Held-to-maturity securities pledged U.S. Government agencies 25,000 Total collateral pledged $ 59,992 Excess collateral 40,033 Securities sold under repurchase agreements $ 19,959

Junior Subordinated Debentures

Junior Subordinated Debentures (Tables)	9 Months Ended
	Sep. 30, 2017
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust [Abstract]
Summary of Junior Subordinated Debentures	The following table provides a summary of the Company’s junior subordinated debentures as of September 30, 2017 . The junior subordinated debentures represent the par value of the obligations owed to the Trusts. (Dollars in thousands) Common Securities Trust Preferred Securities Junior Subordinated Debentures Rate Structure Contractual rate at 9/30/2017 Issue Date Maturity Date Earliest Redemption Date Wintrust Capital Trust III $ 774 $ 25,000 $ 25,774 L+3.25 4.55 % 04/2003 04/2033 04/2008 Wintrust Statutory Trust IV 619 20,000 20,619 L+2.80 4.14 % 12/2003 12/2033 12/2008 Wintrust Statutory Trust V 1,238 40,000 41,238 L+2.60 3.94 % 05/2004 05/2034 06/2009 Wintrust Capital Trust VII 1,550 50,000 51,550 L+1.95 3.27 % 12/2004 03/2035 03/2010 Wintrust Capital Trust VIII 1,238 25,000 26,238 L+1.45 2.79 % 08/2005 09/2035 09/2010 Wintrust Capital Trust IX 1,547 50,000 51,547 L+1.63 2.95 % 09/2006 09/2036 09/2011 Northview Capital Trust I 186 6,000 6,186 L+3.00 4.31 % 08/2003 11/2033 08/2008 Town Bankshares Capital Trust I 186 6,000 6,186 L+3.00 4.31 % 08/2003 11/2033 08/2008 First Northwest Capital Trust I 155 5,000 5,155 L+3.00 4.34 % 05/2004 05/2034 05/2009 Suburban Illinois Capital Trust II 464 15,000 15,464 L+1.75 3.07 % 12/2006 12/2036 12/2011 Community Financial Shares Statutory Trust II 109 3,500 3,609 L+1.62 2.94 % 06/2007 09/2037 06/2012 Total $ 253,566 3.52 %

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Summary of Segment Information	The following is a summary of certain operating information for reportable segments: Three months ended $ Change in Contribution % Change in Contribution (Dollars in thousands) September 30, September 30, Net interest income: Community Banking $ 176,526 $ 150,159 $ 26,367 18 % Specialty Finance 30,501 25,543 4,958 19 Wealth Management 4,557 4,835 (278 ) (6 ) Total Operating Segments 211,584 180,537 31,047 17 Intersegment Eliminations 4,404 4,099 305 7 Consolidated net interest income $ 215,988 $ 184,636 $ 31,352 17 % Non-interest income: Community Banking $ 52,554 $ 62,730 $ (10,176 ) (16 )% Specialty Finance 16,315 12,226 4,089 33 Wealth Management 20,371 20,045 326 2 Total Operating Segments 89,240 95,001 (5,761 ) (6 ) Intersegment Eliminations (9,509 ) (8,397 ) (1,112 ) (13 ) Consolidated non-interest income $ 79,731 $ 86,604 $ (6,873 ) (8 )% Net revenue: Community Banking $ 229,080 $ 212,889 $ 16,191 8 % Specialty Finance 46,816 37,769 9,047 24 Wealth Management 24,928 24,880 48 — Total Operating Segments 300,824 275,538 25,286 9 Intersegment Eliminations (5,105 ) (4,298 ) (807 ) (19 ) Consolidated net revenue $ 295,719 $ 271,240 $ 24,479 9 % Segment profit: Community Banking $ 44,799 $ 37,527 $ 7,272 19 % Specialty Finance 17,043 12,767 4,276 33 Wealth Management 3,784 2,821 963 34 Consolidated net income $ 65,626 $ 53,115 $ 12,511 24 % Segment assets: Community Banking $ 22,426,049 $ 21,019,002 $ 1,407,047 7 % Specialty Finance 4,305,960 3,702,241 603,719 16 Wealth Management 626,153 600,516 25,637 4 Consolidated total assets $ 27,358,162 $ 25,321,759 $ 2,036,403 8 % Nine months ended $ Change in Contribution % Change in Contribution (Dollars in thousands) September 30, September 30, Net interest income: Community Banking $ 499,135 $ 434,108 $ 65,027 15 % Specialty Finance 85,871 71,075 14,796 21 Wealth Management 14,532 13,701 831 6 Total Operating Segments 599,538 518,884 80,654 16 Intersegment Eliminations 13,439 12,531 908 7 Consolidated net interest income $ 612,977 $ 531,415 $ 81,562 15 % Non-interest income: Community Banking $ 160,277 $ 169,210 $ (8,933 ) (5 )% Specialty Finance 44,192 37,111 7,081 19 Wealth Management 61,746 58,660 3,086 5 Total Operating Segments 266,215 264,981 1,234 — Intersegment Eliminations (27,747 ) (24,826 ) (2,921 ) (12 ) Consolidated non-interest income $ 238,468 $ 240,155 $ (1,687 ) (1 )% Net revenue: Community Banking $ 659,412 $ 603,318 $ 56,094 9 % Specialty Finance 130,063 108,186 21,877 20 Wealth Management 76,278 72,361 3,917 5 Total Operating Segments 865,753 783,865 81,888 10 Intersegment Eliminations (14,308 ) (12,295 ) (2,013 ) (16 ) Consolidated net revenue $ 851,445 $ 771,570 $ 79,875 10 % Segment profit: Community Banking $ 128,502 $ 106,860 $ 21,642 20 % Specialty Finance 47,990 36,283 11,707 32 Wealth Management 12,409 9,124 3,285 36 Consolidated net income $ 188,901 $ 152,267 $ 36,634 24 %

Derivative Financial Instrume35

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule Of Fair Value Of Derivative Financial Instruments	The table below presents the fair value of the Company’s derivative financial instruments as of September 30, 2017 , December 31, 2016 and September 30, 2016 : Derivative Assets Derivative Liabilities (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, Derivatives designated as hedging instruments under ASC 815: Interest rate derivatives designated as Cash Flow Hedges $ 8,643 $ 8,011 $ 549 $ — $ — $ 7 Interest rate derivatives designated as Fair Value Hedges 2,036 2,228 177 53 — 907 Total derivatives designated as hedging instruments under ASC 815 $ 10,679 $ 10,239 $ 726 $ 53 $ — $ 914 Derivatives not designated as hedging instruments under ASC 815: Interest rate derivatives $ 34,489 $ 38,974 $ 79,477 $ 33,982 $ 37,665 $ 79,199 Interest rate lock commitments 2,851 4,265 8,352 1 1,325 4,060 Forward commitments to sell mortgage loans 19 2,037 — 1,495 — 3,505 Foreign exchange contracts 160 879 273 242 849 270 Total derivatives not designated as hedging instruments under ASC 815 $ 37,519 $ 46,155 $ 88,102 $ 35,720 $ 39,839 $ 87,034 Total Derivatives $ 48,198 $ 56,394 $ 88,828 $ 35,773 $ 39,839 $ 87,948
Schedule Of Cash Flow Hedging Instruments	The table below provides details on each of these cash flow hedges as of September 30, 2017 : September 30, 2017 (Dollars in thousands) Notional Fair Value Maturity Date Amount Asset (Liability) Interest Rate Swaps: June 2019 $ 200,000 $ 295 July 2019 250,000 3,549 August 2019 275,000 4,434 June 2020 200,000 365 Total Cash Flow Hedges $ 925,000 $ 8,643
Rollforward Of Amounts In Accumulated Other Comprehensive Income Related To Interest Rate Swaps Designated As Cash Flow Hedges	A rollforward of the amounts in accumulated other comprehensive loss related to interest rate derivatives designated as cash flow hedges follows: Three months ended Nine months ended (Dollars in thousands) September 30, September 30, September 30, September 30, Unrealized gain (loss) at beginning of period $ 8,249 $ (3,574 ) $ 6,944 $ (3,529 ) Amount reclassified from accumulated other comprehensive loss to interest expense on deposits and junior subordinated debentures 14 1,065 1,051 2,620 Amount of (loss) gain recognized in other comprehensive income 380 1,708 648 108 Unrealized gain (loss) at end of period $ 8,643 $ (801 ) $ 8,643 $ (801 )
Derivatives Used To Hedge Changes In Fair Value Attributable To Interest Rate Risk	The following table presents the gain/(loss) and hedge ineffectiveness recognized on derivative instruments and the related hedged items that are designated as a fair value hedge accounting relationship as of September 30, 2017 and 2016 : (Dollars in thousands) Derivatives in Fair Value Location of Gain/(Loss) Amount of (Loss)/Gain Recognized Three Months Ended Amount of Gain/(Loss) Recognized Three Months Ended Income Statement Gain Three Months Ended September 30, September 30, September 30, September 30, September 30, September 30, Interest rate swaps Trading losses, net $ (64 ) $ 269 $ 76 $ (234 ) $ 12 $ 35 (Dollars in thousands) Derivatives in Fair Value Hedging Relationships Location of Gain/(Loss) Recognized in Income on Derivative Amount of Loss Recognized in Income on Derivative Nine Months Ended Amount of Gain Recognized in Income on Hedged Item Nine Months Ended Income Statement Gain due to Hedge Ineffectiveness Nine Months Ended September 30, September 30, September 30, September 30, September 30, September 30, Interest rate swaps Trading losses, net $ (245 ) $ (614 ) $ 286 $ 627 $ 41 $ 13
Summary Amounts Included In Consolidated Statement Of Income Related To Derivatives	Amounts included in the Consolidated Statements of Income related to derivative instruments not designated in hedge relationships were as follows: (Dollars in thousands) Three Months Ended Nine Months Ended Derivative Location in income statement September 30, September 30, September 30, September 30, Interest rate swaps and caps Trading losses, net $ (94 ) $ (395 ) $ (762 ) $ (751 ) Mortgage banking derivatives Mortgage banking revenue 708 (2,215 ) 1,398 (3,058 ) Covered call options Fees from covered call options 1,143 3,633 2,792 9,994 Foreign exchange contracts Trading losses, net (23 ) (26 ) (115 ) (262 )
Offsetting Assets	The tables below summarize the Company's interest rate derivatives and offsetting positions as of the dates shown. Derivative Assets Derivative Liabilities Fair Value Fair Value (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, Gross Amounts Recognized $ 45,168 $ 49,213 $ 80,203 $ 34,035 $ 37,665 $ 80,113 Less: Amounts offset in the Statements of Financial Condition — — — — — — Net amount presented in the Statements of Financial Condition $ 45,168 $ 49,213 $ 80,203 $ 34,035 $ 37,665 $ 80,113 Gross amounts not offset in the Statements of Financial Condition Offsetting Derivative Positions $ (16,213 ) (14,441 ) (958 ) $ (16,213 ) (14,441 ) (958 ) Collateral Posted (1) (2,950 ) (8,530 ) — (17,130 ) (12,400 ) (79,155 ) Net Credit Exposure $ 26,005 $ 26,242 $ 79,245 $ 692 $ 10,824 $ — (1) As of September 30, 2016, the Company posted collateral of $86.0 million , which resulted in excess collateral with its counterparties. For purposes of this disclosure, the amount of posted collateral is limited to the amount offsetting the derivative liability.
Offsetting Liabilities	The tables below summarize the Company's interest rate derivatives and offsetting positions as of the dates shown. Derivative Assets Derivative Liabilities Fair Value Fair Value (Dollars in thousands) September 30, December 31, September 30, September 30, December 31, September 30, Gross Amounts Recognized $ 45,168 $ 49,213 $ 80,203 $ 34,035 $ 37,665 $ 80,113 Less: Amounts offset in the Statements of Financial Condition — — — — — — Net amount presented in the Statements of Financial Condition $ 45,168 $ 49,213 $ 80,203 $ 34,035 $ 37,665 $ 80,113 Gross amounts not offset in the Statements of Financial Condition Offsetting Derivative Positions $ (16,213 ) (14,441 ) (958 ) $ (16,213 ) (14,441 ) (958 ) Collateral Posted (1) (2,950 ) (8,530 ) — (17,130 ) (12,400 ) (79,155 ) Net Credit Exposure $ 26,005 $ 26,242 $ 79,245 $ 692 $ 10,824 $ — (1) As of September 30, 2016, the Company posted collateral of $86.0 million , which resulted in excess collateral with its counterparties. For purposes of this disclosure, the amount of posted collateral is limited to the amount offsetting the derivative liability.

Fair Values of Assets and Lia36

Fair Values of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Summary Of Balances Of Assets And Liabilities Measured At Fair Value On A Recurring Basis	The following tables present the balances of assets and liabilities measured at fair value on a recurring basis for the periods presented: September 30, 2017 (Dollars in thousands) Total Level 1 Level 2 Level 3 Available-for-sale securities U.S. Treasury $ 144,145 $ — $ 144,145 $ — U.S. Government agencies 159,328 — 155,385 3,943 Municipal 116,016 — 47,633 68,383 Corporate notes 60,614 — 60,614 — Mortgage-backed 1,149,448 — 1,149,448 — Equity securities 36,352 — 36,352 — Trading account securities 643 — 643 — Mortgage loans held-for-sale 370,282 — 370,282 — Loans held-for-investment 29,704 — — 29,704 MSRs 29,414 — — 29,414 Nonqualified deferred compensation assets 10,824 — 10,824 — Derivative assets 48,198 — 46,982 1,216 Total $ 2,154,968 $ — $ 2,022,308 $ 132,660 Derivative liabilities $ 35,773 $ — $ 35,773 $ — December 31, 2016 (Dollars in thousands) Total Level 1 Level 2 Level 3 Available-for-sale securities U.S. Treasury $ 141,983 $ — $ 141,983 $ — U.S. Government agencies 189,152 — 189,152 — Municipal 131,809 — 52,183 79,626 Corporate notes 65,391 — 65,391 — Mortgage-backed 1,161,084 — 1,161,084 — Equity securities 35,248 — 35,248 — Trading account securities 1,989 — 1,989 — Mortgage loans held-for-sale 418,374 — 418,374 — Loans held-for-investment 22,137 — — 22,137 MSRs 19,103 — — 19,103 Nonqualified deferred compensation assets 9,228 — 9,228 — Derivative assets 56,394 — 54,103 2,291 Total $ 2,251,892 $ — $ 2,128,735 $ 123,157 Derivative liabilities $ 39,839 $ — $ 39,839 $ — September 30, 2016 (Dollars in thousands) Total Level 1 Level 2 Level 3 Available-for-sale securities U.S. Treasury $ 30,036 $ — $ 30,036 $ — U.S. Government agencies 93,683 — 93,683 — Municipal 109,281 — 42,073 67,208 Corporate notes 65,203 — 65,203 — Mortgage-backed 1,301,111 — 1,301,111 — Equity securities 50,782 — 50,782 — Trading account securities 1,092 — 1,092 — Mortgage loans held-for-sale 559,634 — 559,634 — Loans held-for-investment 17,603 — 17,603 — MSRs 13,901 — — 13,901 Nonqualified deferred compensation assets 9,218 — 9,218 — Derivative assets 88,828 — 82,791 6,037 Total $ 2,340,372 $ — $ 2,253,226 $ 87,146 Derivative liabilities $ 87,948 $ — $ 87,948 $ —
Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis	The changes in Level 3 assets measured at fair value on a recurring basis during the three and nine months ended September 30, 2017 and 2016 are summarized as follows: Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at July 1, 2017 $ 77,341 $ — $ 4,110 $ 30,173 $ 27,307 $ 1,047 Total net gains (losses) included in: Net income (1) — — — 177 2,107 169 Other comprehensive loss (4,113 ) — (167 ) — — — Purchases — — — — — — Issuances — — — — — — Sales — — — — — — Settlements (4,845 ) — — (4,504 ) — — Net transfers into/(out of) Level 3 — — — 3,858 — — Balance at September 30, 2017 $ 68,383 $ — $ 3,943 $ 29,704 $ 29,414 $ 1,216 (1) Changes in the balance of MSRs are recorded as a component of mortgage banking revenue in non-interest income. Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at January 1, 2017 $ 79,626 $ — $ — $ 22,137 $ 19,103 $ 2,291 Total net gains (losses) included in: Net income (1) — — — 1,369 10,311 (1,075 ) Other comprehensive loss (1,084 ) — (340 ) — — — Purchases 10,879 — — — — — Issuances — — — — — — Sales — — — — — — Settlements (21,038 ) — — (9,995 ) — — Net transfers into/(out of) Level 3 — — 4,283 16,193 — — Balance at September 30, 2017 $ 68,383 $ — $ 3,943 $ 29,704 $ 29,414 $ 1,216 Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at July 1, 2016 $ 69,812 $ 25,187 $ — $ — $ 13,382 $ 9,731 Total net gains (losses) included in: Net income (1) — — — — 519 (3,694 ) Other comprehensive loss (241 ) — — — — Purchases 2,184 — — — — — Issuances — — — — — — Sales — (25,187 ) — — — — Settlements (4,547 ) — — — — — Net transfers into/(out of) Level 3 — — — — — — Balance at September 30, 2016 $ 67,208 $ — $ — $ — $ 13,901 $ 6,037 Equity securities U.S. Government Agencies Loans held-for- investment Mortgage servicing rights Derivative Assets (Dollars in thousands) Municipal Balance at January 1, 2016 $ 68,613 $ 25,199 $ — $ — $ 9,092 $ 7,021 Total net gains (losses) included in: Net income (1) — — — — 4,809 (984 ) Other comprehensive loss (141 ) (12 ) — — — — Purchases 6,458 — — — — — Issuances — — — — — — Sales — (25,187 ) — — — — Settlements (7,722 ) — — — — — Net transfers into/(out of) Level 3 — — — — — — Balance at September 30, 2016 $ 67,208 $ — $ — $ — $ 13,901 $ 6,037 (1) Changes in the balance of MSRs are recorded as a component of mortgage banking revenue in non-interest income.
Summary Of Assets Measured At Fair Value On A Nonrecurring Basis	For assets measured at fair value on a nonrecurring basis that were still held in the balance sheet at the end of the period, the following table provides the carrying value of the related individual assets or portfolios at September 30, 2017 . September 30, 2017 Three Months Ended September 30, 2017 Fair Value Losses Recognized, net Nine Months Ended September 30, 2017 Fair Value Losses Recognized, net (Dollars in thousands) Total Level 1 Level 2 Level 3 Impaired loans—collateral based $ 57,548 $ — $ — $ 57,548 $ 4,259 $ 10,589 Other real estate owned, including covered other real estate owned (1) 40,229 — — 40,229 490 1,760 Total $ 97,777 $ — $ — $ 97,777 $ 4,749 $ 12,349 (1) Fair value losses recognized, net on other real estate owned include valuation adjustments and charge-offs during the respective period.
Schedule Of Valuation Techniques And Significant Unobservable Inputs Used To Measure Both Recurring And Non-Recurring	The valuation techniques and significant unobservable inputs used to measure both recurring and non-recurring Level 3 fair value measurements at September 30, 2017 were as follows: (Dollars in thousands) Fair Value Valuation Methodology Significant Unobservable Input Range of Inputs Weighted Average of Inputs Impact to valuation from an increased or higher input value Measured at fair value on a recurring basis: Municipal Securities $ 68,383 Bond pricing Equivalent rating BBB-AA+ N/A Increase U.S. Government agencies 3,943 Bond pricing Equivalent rating AAA AAA Increase Loans held-for-investment 29,704 Discounted cash flows Discount rate 3%-4% 3.65% Decrease Credit loss rate 0%-3% 0.94% Decrease Constant prepayment rate (CPR) 9.62% 9.62% Decrease MSRs 29,414 Discounted cash flows Discount rate 9%-15% 9.97% Decrease Constant prepayment rate (CPR) 0%-47% 10.50% Decrease Cost of servicing $65-$200 $69 Decrease Cost of servicing - delinquent $200-$1,000 $634 Decrease Derivatives 1,216 Discounted cash flows Pull-through rate 38%-100% 88.85% Increase Measured at fair value on a non-recurring basis: Impaired loans—collateral based $ 57,548 Appraisal value Appraisal adjustment - cost of sale 10% 10.00% Decrease Other real estate owned, including covered other real estate owned 40,229 Appraisal value Appraisal adjustment - cost of sale 10% 10.00% Decrease
Summary Of Carrying Amounts And Estimated Fair Values Of Financial Instruments	The table below presents the carrying amounts and estimated fair values of the Company’s financial instruments as of the dates shown: At September 30, 2017 At December 31, 2016 At September 30, 2016 Carrying Fair Carrying Fair Carrying Fair (Dollars in thousands) Value Value Value Value Value Value Financial Assets: Cash and cash equivalents $ 251,952 $ 251,952 $ 270,045 $ 270,045 $ 246,947 $ 246,947 Interest bearing deposits with banks 1,218,728 1,218,728 980,457 980,457 816,104 816,104 Available-for-sale securities 1,665,903 1,665,903 1,724,667 1,724,667 1,650,096 1,650,096 Held-to-maturity securities 819,340 807,036 635,705 607,602 932,767 942,666 Trading account securities 643 643 1,989 1,989 1,092 1,092 FHLB and FRB stock, at cost 87,192 87,192 133,494 133,494 129,630 129,630 Brokerage customer receivables 23,631 23,631 25,181 25,181 25,511 25,511 Mortgage loans held-for-sale, at fair value 370,282 370,282 418,374 418,374 559,634 559,634 Loans held-for-investment, at fair value 29,704 29,704 22,137 22,137 17,603 17,603 Loans held-for-investment, at amortized cost 20,929,678 21,064,801 19,739,180 20,755,320 19,179,598 20,233,915 MSRs 29,414 29,414 19,103 19,103 13,901 13,901 Nonqualified deferred compensation assets 10,824 10,824 9,228 9,228 9,218 9,218 Derivative assets 48,198 48,198 56,394 56,394 88,828 88,828 Accrued interest receivable and other 225,435 225,435 204,513 204,513 205,725 205,725 Total financial assets $ 25,710,924 $ 25,833,743 $ 24,240,467 $ 25,228,504 $ 23,876,654 $ 24,940,870 Financial Liabilities Non-maturity deposits $ 18,228,388 $ 18,228,388 $ 17,383,729 $ 17,383,729 $ 16,946,178 $ 16,946,178 Deposits with stated maturities 4,666,675 4,608,760 4,274,903 4,263,576 4,201,477 4,200,278 FHLB advances 468,962 454,753 153,831 157,051 419,632 427,103 Other borrowings 251,680 251,680 262,486 262,486 241,366 241,366 Subordinated notes 139,052 145,376 138,971 135,268 138,943 138,715 Junior subordinated debentures 253,566 240,305 253,566 254,384 253,566 254,108 Derivative liabilities 35,773 35,773 39,839 39,839 87,948 87,948 FDIC indemnification liability 15,472 15,472 16,701 16,701 17,945 17,945 Accrued interest payable 9,177 9,177 6,421 6,421 8,007 8,007 Total financial liabilities $ 24,068,745 $ 23,989,684 $ 22,530,447 $ 22,519,455 $ 22,315,062 $ 22,321,648

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Share-based Compensation [Abstract]
Weighted Average Assumptions Used To Determine The Options Fair Value	The following table presents the weighted average assumptions used to determine the fair value of options granted in the nine month period ended September 30, 2016 . No options were granted in the nine month period ended September 30, 2017 . Nine Months Ended September 30, 2016 Expected dividend yield 0.9 % Expected volatility 25.2 % Risk-free rate 1.3 % Expected option life (in years) 4.5
Summary Of Stock Option Activity	A summary of the Company's stock option activity for the nine months ended September 30, 2017 and September 30, 2016 is presented below: Stock Options Common Shares Weighted Average Strike Price Remaining Contractual Term (1) Intrinsic Value (2) ($000) Outstanding at January 1, 2017 1,698,912 $ 41.50 Granted — — Exercised (499,222 ) 40.57 Forfeited or canceled (16,378 ) 43.07 Outstanding at September 30, 2017 1,183,312 $ 41.87 4.2 $ 43,122 Exercisable at September 30, 2017 640,759 $ 41.58 3.5 $ 23,532 (1) Represents the remaining weighted average contractual life in years. (2) Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company's stock price on the last trading day of the quarter and the option exercise price, multiplied by the number of shares) that would have been received by the option holders if they had exercised their options on the last day of the quarter. Options with exercise prices above the stock price on the last trading day of the quarter are excluded from the calculation of intrinsic value. The intrinsic value will change based on the fair market value of the Company's stock. Stock Options Common Shares Weighted Average Strike Price Remaining Contractual Term (1) Intrinsic Value (2) ($000) Outstanding at January 1, 2016 1,551,734 $ 41.32 Granted 562,166 41.04 Exercised (184,366 ) 37.43 Forfeited or canceled (86,039 ) 48.93 Outstanding at September 30, 2016 1,843,495 $ 41.27 4.8 $ 26,363 Exercisable at September 30, 2016 813,666 $ 39.27 3.5 $ 13,265 (1) Represents the remaining weighted average contractual life in years. (2) Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company's stock price on the last trading day of the quarter and the option exercise price, multiplied by the number of shares) that would have been received by the option holders if they had exercised their options on the last day of the quarter. Options with exercise prices above the stock price on the last trading day of the quarter are excluded from the calculation of intrinsic value. The intrinsic value will change based on the fair market value of the Company's stock.
Summary Of Plans' Restricted Share And Performance-Vested Stock Award Activity	A summary of the Plans' restricted share activity for the nine months ended September 30, 2017 and September 30, 2016 is presented below: Nine months ended September 30, 2017 Nine months ended September 30, 2016 Restricted Shares Common Shares Weighted Average Grant-Date Fair Value Common Shares Weighted Average Grant-Date Fair Value Outstanding at January 1 133,425 $ 49.94 137,593 $ 49.63 Granted 14,249 72.53 15,764 44.72 Vested and issued (10,695 ) 46.03 (10,041 ) 43.78 Forfeited or canceled (2,551 ) 52.26 (598 ) 44.26 Outstanding at September 30 134,428 $ 52.60 142,718 $ 49.52 Vested, but not issuable at September 30 89,563 $ 51.59 88,889 $ 51.44 A summary of the Plans' performance-based stock award activity, based on the target level of the awards, for the nine months ended September 30, 2017 and September 30, 2016 is presented below: Nine months ended September 30, 2017 Nine months ended September 30, 2016 Performance-based Stock Common Weighted Common Weighted Outstanding at January 1 298,180 $ 43.64 276,533 $ 43.01 Granted 145,829 72.60 118,072 41.02 Vested and issued (68,712 ) 46.85 (78,410 ) 37.90 Forfeited (14,164 ) 52.81 (13,229 ) 41.12 Outstanding at September 30 361,133 $ 54.36 302,966 $ 43.64 Vested, but deferred at September 30 13,616 $ 42.66 6,660 $ 37.93

Shareholders' Equity and Earn38

Shareholders' Equity and Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Components Of Other Comprehensive Income (Loss)	The following tables summarize the components of other comprehensive income (loss), including the related income tax effects, and the related amount reclassified to net income for the periods presented (in thousands). Accumulated Unrealized Gains (Losses) on Securities Accumulated Unrealized Losses on Derivative Instruments Accumulated Foreign Currency Translation Adjustments Total Accumulated Other Comprehensive Loss Balance at July 1, 2017 $ (15,022 ) $ 4,959 $ (36,474 ) $ (46,537 ) Other comprehensive income (loss) during the period, net of tax, before reclassifications 653 228 4,206 5,087 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (24 ) 8 — (16 ) Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax (20 ) — — (20 ) Net other comprehensive income during the period, net of tax $ 609 $ 236 $ 4,206 $ 5,051 Balance at September 30, 2017 $ (14,413 ) $ 5,195 $ (32,268 ) $ (41,486 ) Balance at January 1, 2017 $ (29,309 ) $ 4,165 $ (40,184 ) $ (65,328 ) Other comprehensive income (loss) during the period, net of tax, before reclassifications 15,815 393 7,916 24,124 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (19 ) 637 — 618 Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax $ (900 ) $ — $ — $ (900 ) Net other comprehensive income during the period, net of tax $ 14,896 $ 1,030 $ 7,916 $ 23,842 Balance at September 30, 2017 $ (14,413 ) $ 5,195 $ (32,268 ) $ (41,486 ) Balance at July 1, 2016 $ 3,971 $ (2,220 ) $ (36,191 ) $ (34,440 ) Other comprehensive income (loss) during the period, net of tax, before reclassifications 1,532 1,037 (1,644 ) 925 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (2,005 ) 646 — (1,359 ) Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax 2,295 — — 2,295 Net other comprehensive income (loss) during the period, net of tax $ 1,822 $ 1,683 $ (1,644 ) $ 1,861 Balance at September 30, 2016 $ 5,793 $ (537 ) $ (37,835 ) $ (32,579 ) Balance at January 1, 2016 $ (17,674 ) $ (2,193 ) $ (42,841 ) $ (62,708 ) Other comprehensive income during the period, net of tax, before reclassifications 20,444 66 5,006 25,516 Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax (3,684 ) 1,590 — (2,094 ) Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax 6,707 — — 6,707 Net other comprehensive income during the period, net of tax $ 23,467 $ 1,656 $ 5,006 $ 30,129 Balance at September 30, 2016 $ 5,793 $ (537 ) $ (37,835 ) $ (32,579 )
Other Comprehensive Income Reclassified from AOCI	Amount Reclassified from Accumulated Other Comprehensive Income for the Details Regarding the Component of Accumulated Other Comprehensive Income Three Months Ended Nine Months Ended Impacted Line on the Consolidated Statements of Income September 30, September 30, 2017 2016 2017 2016 Accumulated unrealized losses on securities Gains included in net income $ 39 $ 3,305 $ 31 $ 6,070 Gains on investment securities, net 39 3,305 31 6,070 Income before taxes Tax effect $ (15 ) $ (1,300 ) $ (12 ) $ (2,386 ) Income tax expense Net of tax $ 24 $ 2,005 $ 19 $ 3,684 Net income Accumulated unrealized losses on derivative instruments Amount reclassified to interest expense on deposits $ (380 ) $ 528 $ (15 ) $ 1,121 Interest on deposits Amount reclassified to interest expense on junior subordinated debentures 394 537 $ 1,066 $ 1,499 Interest on junior subordinated debentures (14 ) (1,065 ) (1,051 ) (2,620 ) Income before taxes Tax effect $ 6 $ 419 $ 414 $ 1,030 Income tax expense Net of tax $ (8 ) $ (646 ) $ (637 ) $ (1,590 ) Net income
Computation Of Basic And Diluted Earnings Per Common Share	The following table shows the computation of basic and diluted earnings per share for the periods indicated: Three Months Ended Nine Months Ended (In thousands, except per share data) September 30, September 30, September 30, September 30, Net income $ 65,626 $ 53,115 $ 188,901 $ 152,267 Less: Preferred stock dividends 2,050 3,628 7,728 10,884 Net income applicable to common shares—Basic (A) 63,576 49,487 181,173 141,383 Add: Dividends on convertible preferred stock, if dilutive — 1,578 1,578 4,735 Net income applicable to common shares—Diluted (B) 63,576 51,065 182,751 146,118 Weighted average common shares outstanding (C) 55,796 51,679 54,292 49,763 Effect of dilutive potential common shares Common stock equivalents 966 938 988 822 Convertible preferred stock, if dilutive — 3,109 1,317 3,109 Total dilutive potential common shares 966 4,047 2,305 3,931 Weighted average common shares and effect of dilutive potential common shares (D) 56,762 55,726 56,597 53,694 Net income per common share: Basic (A/C) $ 1.14 $ 0.96 $ 3.34 $ 2.84 Diluted (B/D) $ 1.12 $ 0.92 $ 3.23 $ 2.72

Recent Accounting Developments

Recent Accounting Developments (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Excess tax benefits within income tax expense from ASU 2016-09 adoption	$ 5

Business Combinations (Narrativ

Business Combinations (Narrative) (Detail) $ in Thousands	Feb. 14, 2017USD ($)	Nov. 18, 2016USD ($)locations	Mar. 31, 2016USD ($)locations	Jun. 30, 2017USD ($)	Sep. 30, 2017USD ($)financial_institutionLoan	Aug. 19, 2016USD ($)
Business Acquisition [Line Items]
Goodwill recorded on acquisition					$ 999
FDIC loss sharing percentage on purchased loans, OREO, and certain other assets					80.00%
Reduction in estimated loss share liability				$ 4,900
First Community Financial Corporatiion (FCFC)
Business Acquisition [Line Items]
Number of locations | locations		2
Assets acquired		$ 187,200
Loans acquired		79,500
Assumed deposits		150,300
Goodwill recorded on acquisition		$ 13,800
GE Capital Franchise Finance
Business Acquisition [Line Items]
Loans acquired						$ 561,400
Generations Bancorp Inc.
Business Acquisition [Line Items]
Number of locations | locations			1
Assets acquired			$ 134,200
Loans acquired			67,400
Assumed deposits			100,200
Goodwill recorded on acquisition			$ 11,500
FDIC Assisted
Business Acquisition [Line Items]
Number of FDIC assisted banks acquired | financial_institution					9
Loans subject to loss share agreements with FDIC | Loan					8
American Homestead Mortgage, LLC (AHM)
Business Acquisition [Line Items]
Goodwill recorded on acquisition	$ 999

Business Combinations (Summary

Business Combinations (Summary of FDIC Indemnification Asset) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period	$ 15,375	$ 11,729	$ 16,701	$ 6,100
Reductions from reimbursable expenses	(159)	(21)	(316)	(751)
Amortization	311	456	1,010	1,322
Changes in expected reimbursements from (to) the FDIC for changes in expected credit losses and reimbursable expenses	994	4,077	(1,665)	9,150
Payments (paid to) received from the FDIC	(1,049)	1,704	(258)	2,124
Balance at end of period	$ 15,472	$ 17,945	$ 15,472	$ 17,945

Investment Securities (Marketab

Investment Securities (Marketable Securities) (Detail) - USD ($)	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Available-for-sale securities
Amortized Cost	$ 1,691,632,000	$ 1,776,148,000	$ 1,637,399,000
Gross Unrealized Gains	8,140,000	6,929,000	15,136,000
Gross Unrealized Losses	(33,869,000)	(58,410,000)	(2,439,000)
Available-for-sale securities, at fair value	1,665,903,000	1,724,667,000	1,650,096,000
Held-to-maturity securities
Amortized Cost	819,340,000	635,705,000	932,767,000
Gross Unrealized Gains	2,434,000	654,000	13,092,000
Gross Unrealized Losses	(14,738,000)	(28,757,000)	(3,193,000)
Held-to-maturity securities, at Fair value	807,036,000	607,602,000	942,666,000
U.S. Treasury
Available-for-sale securities
Amortized Cost	144,872,000	142,741,000	30,017,000
Gross Unrealized Gains	0	1,000	19,000
Gross Unrealized Losses	(727,000)	(759,000)	0
Available-for-sale securities, at fair value	144,145,000	141,983,000	30,036,000
U.S. Government agencies
Available-for-sale securities
Amortized Cost	159,884,000	189,540,000	93,561,000
Gross Unrealized Gains	10,000	47,000	163,000
Gross Unrealized Losses	(566,000)	(435,000)	(41,000)
Available-for-sale securities, at fair value	159,328,000	189,152,000	93,683,000
Held-to-maturity securities
Amortized Cost	585,061,000	433,343,000	729,417,000
Gross Unrealized Gains	249,000	7,000	7,577,000
Gross Unrealized Losses	(12,579,000)	(24,470,000)	(2,879,000)
Held-to-maturity securities, at Fair value	572,731,000	408,880,000	734,115,000
Municipal Securities
Available-for-sale securities
Amortized Cost	113,796,000	129,446,000	106,033,000
Gross Unrealized Gains	2,493,000	2,969,000	3,395,000
Gross Unrealized Losses	(273,000)	(606,000)	(147,000)
Available-for-sale securities, at fair value	116,016,000	131,809,000	109,281,000
Held-to-maturity securities
Amortized Cost	234,279,000	202,362,000	203,350,000
Gross Unrealized Gains	2,185,000	647,000	5,515,000
Gross Unrealized Losses	(2,159,000)	(4,287,000)	(314,000)
Held-to-maturity securities, at Fair value	234,305,000	198,722,000	208,551,000
Corporate notes, Financial issuers
Available-for-sale securities
Amortized Cost	60,325,000	65,260,000	65,215,000
Gross Unrealized Gains	63,000	132,000	299,000
Gross Unrealized Losses	(771,000)	(1,000,000)	(1,311,000)
Available-for-sale securities, at fair value	59,617,000	64,392,000	64,203,000
Corporate notes, Other
Available-for-sale securities
Amortized Cost	1,000,000	1,000,000	1,000,000
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(3,000)	(1,000)	0
Available-for-sale securities, at fair value	997,000	999,000	1,000,000
Mortgage-backed securities
Available-for-sale securities
Amortized Cost	1,114,655,000	1,185,448,000	1,257,070,000
Gross Unrealized Gains	1,477,000	284,000	7,958,000
Gross Unrealized Losses	(30,436,000)	(54,330,000)	(54,000)
Available-for-sale securities, at fair value	1,085,696,000	1,131,402,000	1,264,974,000
Collateralized mortgage obligations
Available-for-sale securities
Amortized Cost	63,934,000	30,105,000	35,935,000
Gross Unrealized Gains	230,000	67,000	304,000
Gross Unrealized Losses	(412,000)	(490,000)	(102,000)
Available-for-sale securities, at fair value	63,752,000	29,682,000	36,137,000
Equity securities
Available-for-sale securities
Amortized Cost	33,166,000	32,608,000	48,568,000
Gross Unrealized Gains	3,867,000	3,429,000	2,998,000
Gross Unrealized Losses	(681,000)	(789,000)	(784,000)
Available-for-sale securities, at fair value	36,352,000	35,248,000	50,782,000
Mortgage-backed securities, subprime
Available-for-sale securities
Available-for-sale securities, at fair value	$ 0	$ 0	$ 0

Investment Securities (Investme

Investment Securities (Investment Securities, Continuous Unrealized Loss Position, Fair Value) (Detail) $ in Thousands	Sep. 30, 2017USD ($)
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	$ 366,426
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(8,423)
Continuous unrealized losses existing for greater than 12 months, Fair value	900,366
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(25,446)
Total, Fair value	1,266,792
Total, Unrealized losses	(33,869)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	516,364
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(14,738)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	516,364
Held-to-maturity Securities, Continuous Unrealized Loss Position, Unrealized Losses	(14,738)
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	144,144
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(727)
Continuous unrealized losses existing for greater than 12 months, Fair value	0
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	0
Total, Fair value	144,144
Total, Unrealized losses	(727)
U.S. Government agencies
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	112,268
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(451)
Continuous unrealized losses existing for greater than 12 months, Fair value	41,980
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(115)
Total, Fair value	154,248
Total, Unrealized losses	(566)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	400,980
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(12,579)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	400,980
Held-to-maturity Securities, Continuous Unrealized Loss Position, Unrealized Losses	(12,579)
Municipal Securities
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	24,117
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(138)
Continuous unrealized losses existing for greater than 12 months, Fair value	10,725
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(135)
Total, Fair value	34,842
Total, Unrealized losses	(273)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	115,384
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2,159)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	0
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value	115,384
Held-to-maturity Securities, Continuous Unrealized Loss Position, Unrealized Losses	(2,159)
Corporate notes, Financial issuers
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	0
Continuous unrealized losses existing for less than 12 months, Unrealized losses	0
Continuous unrealized losses existing for greater than 12 months, Fair value	35,194
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(771)
Total, Fair value	35,194
Total, Unrealized losses	(771)
Corporate notes, Other
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	0
Continuous unrealized losses existing for less than 12 months, Unrealized losses	0
Continuous unrealized losses existing for greater than 12 months, Fair value	997
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(3)
Total, Fair value	997
Total, Unrealized losses	(3)
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	51,035
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(6,629)
Continuous unrealized losses existing for greater than 12 months, Fair value	798,152
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(23,807)
Total, Fair value	849,187
Total, Unrealized losses	(30,436)
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	25,685
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(195)
Continuous unrealized losses existing for greater than 12 months, Fair value	7,216
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(217)
Total, Fair value	32,901
Total, Unrealized losses	(412)
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Continuous unrealized losses existing for less than 12 months, Fair value	9,177
Continuous unrealized losses existing for less than 12 months, Unrealized losses	(283)
Continuous unrealized losses existing for greater than 12 months, Fair value	6,102
Continuous unrealized losses existing for greater than 12 months, Unrealized losses	(398)
Total, Fair value	15,279
Total, Unrealized losses	$ (681)

Investment Securities (Schedule

Investment Securities (Schedule of Realized Gain (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Realized gains	$ 58	$ 3,429	$ 106	$ 7,466
Realized losses	(19)	(124)	(75)	(1,396)
Net realized gains	39	3,305	31	6,070
Other than temporary impairment charges	0	0	0	0
Gains on investment securities, net	39	3,305	31	6,070
Proceeds from sales and calls of available-for-sale securities	136,789	1,114,666	146,518	2,186,662
Proceeds from calls of held-to-maturity securities	$ 17	$ 141,885	$ 51,079	$ 423,866

Investment Securities (Invest45

Investment Securities (Investments Classified by Contractual Maturity Date) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	$ 150,907	$ 145,353	$ 115,227
Due in one to five years, Amortized Cost	282,443	321,019	141,364
Due in five to ten years, Amortized Cost	38,339	27,319	28,696
Due after ten years, Amortized Cost	8,188	34,296	10,539
Amortized Cost	1,691,632	1,776,148	1,637,399
Due in one year or less, Fair Value	150,241	145,062	115,487
Due in one to five years, Fair Value	282,121	320,423	141,368
Due in five to ten years, Fair Value	39,458	28,451	31,319
Due after ten years, Fair Value	8,283	34,399	10,029
Available-for-sale securities	1,665,903	1,724,667	1,650,096
Held-to-maturity securities, Due in one year or less, Amortized Cost	170	0	0
Held-to-maturity securities, Due in one to five years, Amortized Cost	36,914	29,794	25,927
Held-to-maturity securities, Due in five to ten years, Amortized Cost	193,387	69,664	64,835
Held-to-maturity securities, Due after ten years, Amortized Cost	588,869	536,247	842,005
Amortized Cost	819,340	635,705	932,767
Held-to-maturity securities, Due in one year or less, Fair Value	171	0	0
Held-to-maturity securities, Due in one to five years, Fair Value	36,734	29,416	26,023
Held-to-maturity securities, Due in five to ten years, Fair Value	192,581	67,820	65,842
Held-to-maturity securities, Due after ten years, Fair Value	577,550	510,366	850,801
Held-to-maturity securities, Fair Value	807,036	607,602	942,666
Mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,178,589	1,215,553	1,293,005
Available-for-sale securities	1,149,448	1,161,084	1,301,111
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	33,166	32,608	48,568
Available-for-sale securities	$ 36,352	$ 35,248	$ 50,782

Investment Securities (Narrativ

Investment Securities (Narrative) (Detail) $ in Billions	Sep. 30, 2017USD ($)securities	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)
Available-for-sale Securities and Held-to-maturity Securities [Abstract]
Pledged Securities, carrying value | $	$ 1.6	$ 1.4	$ 1.4
Number of securities by a single non-goverment sponsored issuer exceeding 10% of shareholders' equity | securities	0

Loans (Summary of Loan Portfoli

Loans (Summary of Loan Portfolio) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 20,912,781	$ 19,703,172	$ 19,101,261
Covered loans	46,601	58,145	95,940
Total loans	$ 20,959,382	$ 19,761,317	$ 19,197,201
Total loans, net of unearned income, excluding covered loans	100.00%	100.00%	100.00%
Covered loans	0.00%	0.00%	0.00%
Total loans	100.00%	100.00%	100.00%
Commercial
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 6,456,034	$ 6,005,422	$ 5,951,544
Total loans, net of unearned income, excluding covered loans	31.00%	30.00%	31.00%
Commercial real estate
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 6,400,781	$ 6,196,087	$ 5,908,684
Total loans, net of unearned income, excluding covered loans	31.00%	31.00%	31.00%
Home equity
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 672,969	$ 725,793	$ 742,868
Total loans, net of unearned income, excluding covered loans	3.00%	4.00%	4.00%
Residential real estate
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 789,499	$ 705,221	$ 663,598
Total loans, net of unearned income, excluding covered loans	3.00%	4.00%	3.00%
Premium finance receivables—commercial | Commercial insurance loans
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 2,664,912	$ 2,478,581	$ 2,430,233
Total loans, net of unearned income, excluding covered loans	13.00%	12.00%	13.00%
Premium finance receivables—commercial | Life insurance
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 3,795,474	$ 3,470,027	$ 3,283,359
Total loans, net of unearned income, excluding covered loans	18.00%	18.00%	17.00%
Consumer and other
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 133,112	$ 122,041	$ 120,975
Total loans, net of unearned income, excluding covered loans	1.00%	1.00%	1.00%

Loans (Schedule of Unpaid Princ

Loans (Schedule of Unpaid Principal Balance And Carrying Value Of Acquired Loans) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Abstract]
Unpaid Principal Balance	$ 406,891	$ 509,446
Carrying Value	$ 379,407	$ 471,786

Loans (Activity Related to Accr

Loans (Activity Related to Accretable Yield of Loans Acquired With Evidence of Credit Quality Deterioration Since Origination) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield, beginning balance	$ 45,510	$ 55,630	$ 49,408	$ 63,902
Acquisitions	0	0	426	1,082
Accretable yield amortized to interest income	(5,025)	(6,449)	(16,101)	(17,105)
Accretable yield amortized to indemnification asset/liability	(371)	(1,744)	(1,086)	(5,539)
Reclassification from non-accretable difference	1,017	5,370	7,106	12,099
Decreases in interest cash flows due to payments and changes in interest rates	(875)	170	503	(1,462)
Accretable yield, ending balance	40,256	$ 52,977	40,256	$ 52,977
Accretable yield, to be amortized to indemnification asset	$ 24		$ 24

Loans (Narrative) (Detail)

Loans (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Schedule Of Accretable Yield Activity Related to Loans Acquired With Evidence Of Credit Quality Deterioration Since Origination Table [Line Items]
Net deferred loan fees and costs and fair value accounting adjustments	$ 8,000	$ 873	$ 8,000	$ 873	$ 2,600
Accretable yield amortized to interest income	5,025	6,449	16,101	17,105
Premium finance receivables
Schedule Of Accretable Yield Activity Related to Loans Acquired With Evidence Of Credit Quality Deterioration Since Origination Table [Line Items]
Unearned income portion of premium finance receivables	$ 80,400	$ 64,400	$ 80,400	$ 64,400	$ 69,600

Allowance for Loan Losses, Al51

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Schedule of Aging of the Company's Loan Portfolio) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	$ 63,436	$ 77,578	$ 77,645
90+ days and still accruing	29,830	33,738	37,396
Current	20,769,265	19,508,748	18,958,594
Loans, net of unearned income, excluding covered loans	20,912,781	19,703,172	19,101,261
Nonaccrual	61,500	75,457	75,314
90+ days and still accruing	27,597	31,246	32,590
Current	20,727,952	19,456,994	18,873,792
Covered loans, Nonaccrual	1,936	2,121	2,331
Covered loans, 90 plus days and still accruing	2,233	2,492	4,806
Covered loans, Current	41,313	51,754	84,802
Covered loans	46,601	58,145	95,940
Total loans	20,959,382	19,761,317	19,197,201
60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	23,058	43,880	50,671
60-89 days past due	21,984	43,655	49,126
Covered loans, 60-89 days past due	1,074	225	1,545
30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	73,793	97,373	72,895
30-59 days past due	73,748	95,820	70,439
Covered loans, 30-59 days past due	45	1,553	2,456
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	13,931	15,875	16,418
90+ days and still accruing	1,489	1,863	1,783
Current	6,399,128	5,967,468	5,906,160
Loans, net of unearned income, excluding covered loans	6,456,034	6,005,422	5,951,544
Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,036	2,576	11,793
Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	36,450	17,640	15,390
Commercial | Commercial, industrial and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	12,281	13,441	15,809
90+ days and still accruing	0	174	0
Current	4,091,381	3,716,977	3,573,396
Loans, net of unearned income, excluding covered loans	4,120,533	3,744,712	3,605,516
Commercial | Commercial, industrial and other | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,161	2,341	7,324
Commercial | Commercial, industrial and other | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	13,710	11,779	8,987
Commercial | Franchise
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	0	0	0
90+ days and still accruing	0	0	0
Current	836,997	869,228	872,661
Loans, net of unearned income, excluding covered loans	853,716	869,721	874,745
Commercial | Franchise | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0	458
Commercial | Franchise | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	16,719	493	1,626
Commercial | Mortgage warehouse lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	0	0	0
90+ days and still accruing	0	0	0
Current	194,058	204,225	309,632
Loans, net of unearned income, excluding covered loans	194,370	204,225	309,632
Commercial | Mortgage warehouse lines of credit | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0	0
Commercial | Mortgage warehouse lines of credit | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	312	0	0
Commercial | Asset-based lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	1,141	1,924	234
90+ days and still accruing	0	0	0
Current	889,147	871,402	837,972
Loans, net of unearned income, excluding covered loans	896,336	875,070	845,719
Commercial | Asset-based lending | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,533	135	3,772
Commercial | Asset-based lending | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,515	1,609	3,741
Commercial | Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	509	510	375
90+ days and still accruing	0	0	0
Current	379,410	293,073	299,339
Loans, net of unearned income, excluding covered loans	381,394	294,914	299,953
Commercial | Leases | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	281	0	239
Commercial | Leases | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,194	1,331	0
Commercial | PCI - commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	0	0	0
90+ days and still accruing	1,489	1,689	1,783
Current	8,135	12,563	13,160
Loans, net of unearned income, excluding covered loans	9,685	16,780	15,979
Commercial | PCI - commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	61	100	0
Commercial | PCI - commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	2,428	1,036
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	14,878	21,924	22,625
90+ days and still accruing	8,443	16,188	21,433
Current	6,354,667	6,110,999	5,813,145
Loans, net of unearned income, excluding covered loans	6,400,781	6,196,087	5,908,684
Commercial real estate | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,838	15,253	16,241
Commercial real estate | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	16,955	31,723	35,240
Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	1,607	2,408	400
90+ days and still accruing	0	0	0
Current	669,940	606,007	447,302
Loans, net of unearned income, excluding covered loans	673,977	610,239	451,477
Commercial real estate | Construction | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	366	0	0
Commercial real estate | Construction | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,064	1,824	3,775
Commercial real estate | Land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	196	394	1,208
90+ days and still accruing	0	0	0
Current	102,557	104,219	105,406
Loans, net of unearned income, excluding covered loans	102,753	104,801	107,701
Commercial real estate | Land | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	188	787
Commercial real estate | Land | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0	300
Commercial real estate | Office
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	5,148	4,337	3,609
90+ days and still accruing	0	0	0
Current	874,583	857,599	865,954
Loans, net of unearned income, excluding covered loans	880,951	867,674	884,082
Commercial real estate | Office | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	4,506	6,457
Commercial real estate | Office | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,220	1,232	8,062
Commercial real estate | Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	1,848	7,047	9,967
90+ days and still accruing	0	0	0
Current	834,062	756,602	753,636
Loans, net of unearned income, excluding covered loans	836,485	770,601	767,504
Commercial real estate | Industrial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	137	4,516	940
Commercial real estate | Industrial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	438	2,436	2,961
Commercial real estate | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	2,200	597	909
90+ days and still accruing	0	0	0
Current	925,335	907,872	884,369
Loans, net of unearned income, excluding covered loans	934,239	912,593	895,341
Commercial real estate | Retail | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,030	760	1,340
Commercial real estate | Retail | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,674	3,364	8,723
Commercial real estate | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	569	643	90
90+ days and still accruing	0	0	0
Current	861,290	805,312	789,645
Loans, net of unearned income, excluding covered loans	864,985	807,624	794,955
Commercial real estate | Multi-family | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	68	322	3,051
Commercial real estate | Multi-family | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,058	1,347	2,169
Commercial real estate | Mixed use and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	3,310	6,498	6,442
90+ days and still accruing	0	0	0
Current	1,966,601	1,931,859	1,837,724
Loans, net of unearned income, excluding covered loans	1,974,315	1,952,175	1,851,507
Commercial real estate | Mixed use and other | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	843	1,186	2,157
Commercial real estate | Mixed use and other | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,561	12,632	5,184
Commercial real estate | PCI - commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	0	0	0
90+ days and still accruing	8,443	16,188	21,433
Current	120,299	141,529	129,109
Loans, net of unearned income, excluding covered loans	133,076	170,380	156,117
Commercial real estate | PCI - commercial real estate | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,394	3,775	1,509
Commercial real estate | PCI - commercial real estate | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,940	8,888	4,066
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	7,581	9,761	9,309
90+ days and still accruing	0	0	0
Current	662,352	707,887	727,989
Loans, net of unearned income, excluding covered loans	672,969	725,793	742,868
Home equity | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	446	1,630	1,728
Home equity | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,590	6,515	3,842
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	14,743	12,749	12,205
90+ days and still accruing	1,120	1,309	1,496
Current	771,416	681,956	646,577
Loans, net of unearned income, excluding covered loans	789,499	705,221	663,598
Residential real estate | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,055	936	2,232
Residential real estate | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	165	8,271	1,088
Premium finance receivables | Commercial insurance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	9,827	14,709	14,214
90+ days and still accruing	9,584	7,962	7,754
Current	2,628,114	2,435,684	2,391,006
Loans, net of unearned income, excluding covered loans	2,664,912	2,478,581	2,430,233
Premium finance receivables | Commercial insurance loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,421	5,646	6,968
Premium finance receivables | Commercial insurance loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	9,966	14,580	10,291
Premium finance receivables | Life insurance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	0	0	0
90+ days and still accruing	6,740	3,717	0
Current	3,571,388	3,182,935	3,006,795
Loans, net of unearned income, excluding covered loans	3,586,011	3,220,370	3,020,472
Premium finance receivables | Life insurance loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	946	17,514	9,960
Premium finance receivables | Life insurance loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,937	16,204	3,717
Premium finance receivables | PCI - life insurance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	0	0	0
90+ days and still accruing	0	0	0
Current	209,463	249,657	262,887
Loans, net of unearned income, excluding covered loans	209,463	249,657	262,887
Premium finance receivables | PCI - life insurance loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0	0
Premium finance receivables | PCI - life insurance loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0	0
Consumer and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	540	439	543
90+ days and still accruing	221	207	124
Current	131,424	120,408	119,233
Loans, net of unearned income, excluding covered loans	133,112	122,041	120,975
Consumer and other | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	242	100	204
Consumer and other | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 685	$ 887	$ 871

Allowance for Loan Losses, Al52

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Performance by Loan Class) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	$ 20,912,781	$ 19,703,172	$ 19,101,261
Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	6,456,034	6,005,422	5,951,544
Commercial | Commercial, industrial and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	4,120,533	3,744,712	3,605,516
Commercial | Franchise
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	853,716	869,721	874,745
Commercial | Mortgage warehouse lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	194,370	204,225	309,632
Commercial | Asset-based lending
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	896,336	875,070	845,719
Commercial | Leases
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	381,394	294,914	299,953
Commercial | PCI - commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	9,685	16,780	15,979
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	6,400,781	6,196,087	5,908,684
Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	673,977	610,239	451,477
Commercial real estate | Land
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	102,753	104,801	107,701
Commercial real estate | Office
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	880,951	867,674	884,082
Commercial real estate | Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	836,485	770,601	767,504
Commercial real estate | Retail
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	934,239	912,593	895,341
Commercial real estate | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	864,985	807,624	794,955
Commercial real estate | Mixed use and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	1,974,315	1,952,175	1,851,507
Commercial real estate | PCI - commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	133,076	170,380	156,117
Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	672,969	725,793	742,868
Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	789,499	705,221	663,598
Premium finance receivables | Commercial insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	2,664,912	2,478,581	2,430,233
Premium finance receivables | Life insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	3,586,011	3,220,370	3,020,472
Premium finance receivables | PCI - life insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	209,463	249,657	262,887
Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	133,112	122,041	120,975
Performing
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	20,834,798	19,615,718	19,018,133
Performing | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	6,442,103	5,989,373	5,935,126
Performing | Commercial | Commercial, industrial and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	4,108,252	3,731,097	3,589,707
Performing | Commercial | Franchise
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	853,716	869,721	874,745
Performing | Commercial | Mortgage warehouse lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	194,370	204,225	309,632
Performing | Commercial | Asset-based lending
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	895,195	873,146	845,485
Performing | Commercial | Leases
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	380,885	294,404	299,578
Performing | Commercial | PCI - commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	9,685	16,780	15,979
Performing | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	6,385,903	6,174,163	5,886,059
Performing | Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	672,370	607,831	451,077
Performing | Commercial real estate | Land
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	102,557	104,407	106,493
Performing | Commercial real estate | Office
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	875,803	863,337	880,473
Performing | Commercial real estate | Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	834,637	763,554	757,537
Performing | Commercial real estate | Retail
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	932,039	911,996	894,432
Performing | Commercial real estate | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	864,416	806,981	794,865
Performing | Commercial real estate | Mixed use and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	1,971,005	1,945,677	1,845,065
Performing | Commercial real estate | PCI - commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	133,076	170,380	156,117
Performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	665,388	716,032	733,559
Performing | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	774,756	692,472	651,393
Performing | Premium finance receivables | Commercial insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	2,645,501	2,455,910	2,408,265
Performing | Premium finance receivables | Life insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	3,579,271	3,216,653	3,020,472
Performing | Premium finance receivables | PCI - life insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	209,463	249,657	262,887
Performing | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	132,413	121,458	120,372
Non-performing
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	77,983	87,454	83,128
Non-performing | Commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	13,931	16,049	16,418
Non-performing | Commercial | Commercial, industrial and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	12,281	13,615	15,809
Non-performing | Commercial | Franchise
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	0	0	0
Non-performing | Commercial | Mortgage warehouse lines of credit
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	0	0	0
Non-performing | Commercial | Asset-based lending
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	1,141	1,924	234
Non-performing | Commercial | Leases
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	509	510	375
Non-performing | Commercial | PCI - commercial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	0	0	0
Non-performing | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	14,878	21,924	22,625
Non-performing | Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	1,607	2,408	400
Non-performing | Commercial real estate | Land
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	196	394	1,208
Non-performing | Commercial real estate | Office
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	5,148	4,337	3,609
Non-performing | Commercial real estate | Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	1,848	7,047	9,967
Non-performing | Commercial real estate | Retail
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	2,200	597	909
Non-performing | Commercial real estate | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	569	643	90
Non-performing | Commercial real estate | Mixed use and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	3,310	6,498	6,442
Non-performing | Commercial real estate | PCI - commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	0	0	0
Non-performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	7,581	9,761	9,309
Non-performing | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	14,743	12,749	12,205
Non-performing | Premium finance receivables | Commercial insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	19,411	22,671	21,968
Non-performing | Premium finance receivables | Life insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	6,740	3,717	0
Non-performing | Premium finance receivables | PCI - life insurance loans
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	0	0	0
Non-performing | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Loans, net of unearned income, excluding covered loans	$ 699	$ 583	$ 603

Allowance for Loan Losses, Al53

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Activity in the Allowance for Credit Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	$ 129,591	$ 114,356	$ 122,291	$ 105,400
Other adjustments	(39)	(112)	(125)	(324)
Reclassification from allowance for unfunded lending-related commitments	94	(579)	62	(700)
Charge-offs	(6,418)	(6,907)	(16,563)	(18,478)
Recoveries	1,949	1,194	5,244	4,362
Provision for credit losses	7,942	9,741	22,210	27,433
Allowance for loan losses at period end	133,119	117,693	133,119	117,693
Allowance for unfunded lending-related commitments at period end	1,276	1,648	1,276	1,648
Allowance for credit losses at period end	134,395	119,341	134,395	119,341
Individually evaluated for impairment	7,235	7,367	7,235	7,367
Collectively evaluated for impairment	126,446	111,150	126,446	111,150
Loans at period end, Individually evaluated for impairment	79,320	91,374	79,320	91,374
Loans at period end, Collectively evaluated for impairment	20,447,199	18,552,165	20,447,199	18,552,165
Loans held at fair value	29,414	17,603	29,414	17,603
Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	714	824	714	824
Loans at period end, Loans acquired with deteriorated credit quality	356,848	440,119	356,848	440,119
Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	52,358	41,654	44,493	36,135
Other adjustments	(2)	(35)	(23)	(103)
Reclassification from allowance for unfunded lending-related commitments	500	(500)	500	(500)
Charge-offs	(2,265)	(3,469)	(3,819)	(4,861)
Recoveries	801	176	1,635	926
Provision for credit losses	4,343	5,212	12,949	11,441
Allowance for loan losses at period end	55,735	43,038	55,735	43,038
Allowance for unfunded lending-related commitments at period end	0	500	0	500
Allowance for credit losses at period end	55,735	43,538	55,735	43,538
Individually evaluated for impairment	4,568	2,554	4,568	2,554
Collectively evaluated for impairment	50,623	40,252	50,623	40,252
Loans at period end, Individually evaluated for impairment	18,086	19,133	18,086	19,133
Loans at period end, Collectively evaluated for impairment	6,428,263	5,916,432	6,428,263	5,916,432
Loans held at fair value	0	0	0	0
Commercial | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	544	732	544	732
Loans at period end, Loans acquired with deteriorated credit quality	9,685	15,979	9,685	15,979
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	52,339	46,824	51,422	43,758
Other adjustments	(38)	(57)	(121)	(203)
Reclassification from allowance for unfunded lending-related commitments	(406)	(79)	(438)	(200)
Charge-offs	(989)	(382)	(3,235)	(1,555)
Recoveries	323	364	1,153	1,029
Provision for credit losses	811	1,678	3,259	5,519
Allowance for loan losses at period end	52,040	48,348	52,040	48,348
Allowance for unfunded lending-related commitments at period end	1,276	1,148	1,276	1,148
Allowance for credit losses at period end	53,316	49,496	53,316	49,496
Individually evaluated for impairment	1,184	2,491	1,184	2,491
Collectively evaluated for impairment	52,048	46,983	52,048	46,983
Loans at period end, Individually evaluated for impairment	31,698	45,290	31,698	45,290
Loans at period end, Collectively evaluated for impairment	6,236,007	5,707,277	6,236,007	5,707,277
Loans held at fair value	0	0	0	0
Commercial real estate | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	84	22	84	22
Loans at period end, Loans acquired with deteriorated credit quality	133,076	156,117	133,076	156,117
Home equity
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	11,134	11,383	11,774	12,012
Other adjustments	0	0	0	0
Reclassification from allowance for unfunded lending-related commitments	0	0	0	0
Charge-offs	(968)	(574)	(3,224)	(3,672)
Recoveries	178	65	387	184
Provision for credit losses	212	810	1,619	3,160
Allowance for loan losses at period end	10,556	11,684	10,556	11,684
Allowance for unfunded lending-related commitments at period end	0	0	0	0
Allowance for credit losses at period end	10,556	11,684	10,556	11,684
Individually evaluated for impairment	691	964	691	964
Collectively evaluated for impairment	9,865	10,720	9,865	10,720
Loans at period end, Individually evaluated for impairment	7,729	9,309	7,729	9,309
Loans at period end, Collectively evaluated for impairment	665,240	733,559	665,240	733,559
Loans held at fair value	0	0	0	0
Home equity | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	0	0	0	0
Loans at period end, Loans acquired with deteriorated credit quality	0	0	0	0
Residential real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	6,143	5,405	5,714	4,734
Other adjustments	(31)	(10)	(38)	(49)
Reclassification from allowance for unfunded lending-related commitments	0	0	0	0
Charge-offs	(267)	(134)	(742)	(1,320)
Recoveries	55	61	287	204
Provision for credit losses	757	781	1,436	2,534
Allowance for loan losses at period end	6,657	6,103	6,657	6,103
Allowance for unfunded lending-related commitments at period end	0	0	0	0
Allowance for credit losses at period end	6,657	6,103	6,657	6,103
Individually evaluated for impairment	758	1,166	758	1,166
Collectively evaluated for impairment	5,813	4,867	5,813	4,867
Loans at period end, Individually evaluated for impairment	21,263	17,040	21,263	17,040
Loans at period end, Collectively evaluated for impairment	735,185	625,030	735,185	625,030
Loans held at fair value	29,414	17,603	29,414	17,603
Residential real estate | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	86	70	86	70
Loans at period end, Loans acquired with deteriorated credit quality	3,637	3,925	3,637	3,925
Premium finance receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	6,352	7,814	7,625	7,233
Other adjustments	32	(10)	57	31
Reclassification from allowance for unfunded lending-related commitments	0	0	0	0
Charge-offs	(1,716)	(1,959)	(5,021)	(6,350)
Recoveries	499	456	1,515	1,876
Provision for credit losses	1,386	974	2,377	4,485
Allowance for loan losses at period end	6,553	7,275	6,553	7,275
Allowance for unfunded lending-related commitments at period end	0	0	0	0
Allowance for credit losses at period end	6,553	7,275	6,553	7,275
Individually evaluated for impairment	0	0	0	0
Collectively evaluated for impairment	6,553	7,275	6,553	7,275
Loans at period end, Individually evaluated for impairment	0	0	0	0
Loans at period end, Collectively evaluated for impairment	6,250,923	5,450,705	6,250,923	5,450,705
Loans held at fair value	0	0	0	0
Premium finance receivables | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	0	0	0	0
Loans at period end, Loans acquired with deteriorated credit quality	209,463	262,887	209,463	262,887
Consumer and other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses at beginning of period	1,265	1,276	1,263	1,528
Other adjustments	0	0	0	0
Reclassification from allowance for unfunded lending-related commitments	0	0	0	0
Charge-offs	(213)	(389)	(522)	(720)
Recoveries	93	72	267	143
Provision for credit losses	433	286	570	294
Allowance for loan losses at period end	1,578	1,245	1,578	1,245
Allowance for unfunded lending-related commitments at period end	0	0	0	0
Allowance for credit losses at period end	1,578	1,245	1,578	1,245
Individually evaluated for impairment	34	192	34	192
Collectively evaluated for impairment	1,544	1,053	1,544	1,053
Loans at period end, Individually evaluated for impairment	544	602	544	602
Loans at period end, Collectively evaluated for impairment	131,581	119,162	131,581	119,162
Loans held at fair value	0	0	0	0
Consumer and other | Receivables Acquired with Deteriorated Credit Quality
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit losses at period end	0	0	0	0
Loans at period end, Loans acquired with deteriorated credit quality	$ 987	$ 1,211	$ 987	$ 1,211

Allowance for Loan Losses, Al54

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Activity in the Allowance for Covered Loan Losses) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance for Covered Loan Losses [Roll Forward]
Balance at beginning of period	$ 1,074	$ 2,412	$ 1,322	$ 3,026
Provision for covered loan losses before benefit attributable to FDIC loss share agreements	(225)	(847)	(1,063)	(3,495)
Benefit attributable to FDIC loss share agreements	(180)	(677)	(850)	(2,796)
Net provision for covered loan losses	(45)	(170)	(213)	(699)
Increase in FDIC indemnification liability	(180)	(677)	(850)	(2,796)
Loans charged-off	(155)	(918)	(491)	(1,291)
Recoveries of loans charged-off	64	775	990	3,182
Net (charge-offs) recoveries	(91)	(143)	499	1,891
Balance at end of period	$ 758	$ 1,422	$ 758	$ 1,422

Allowance for Loan Losses, Al55

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Impaired Loans, Including Restructured Loans) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financing Receivable, Impaired [Line Items]
Impaired loans with an allowance for loan loss required	$ 30,864	$ 33,146	$ 39,022
Impaired loans with no allowance for loan loss required	47,730	57,370	51,518
Total impaired loans	78,594	90,516	90,540
Allowance for loan losses related to impaired loans	7,218	6,377	6,836
Financing Receivable
Financing Receivable, Impaired [Line Items]
Allowance for loan losses related to impaired loans	1,200
TDRs	$ 33,183	$ 41,708	$ 44,276

Allowance for Loan Losses, Al56

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Impaired Loans by Loan Class) (Detail) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	$ 30,864	$ 39,022	$ 33,146
Impaired Financing Receivable, Related Allowance	7,218	6,836	6,377
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	47,730	51,518	57,370
Impaired Financing Receivable, Recorded Investment	78,594	90,540	90,516
Impaired Financing Receivable, Unpaid Principal Balance	91,091	106,758	103,046
Impaired Financing Receivable, Average Recorded Investment	84,905	94,750	105,423
Impaired Financing Receivable, Interest Income Recognized	3,424	4,066	5,485
Commercial | Commercial, industrial and other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	7,312	5,426	2,601
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	8,458	5,434	2,617
Impaired Financing Receivable, Related Allowance	4,191	1,887	1,079
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	8,390	5,487	2,649
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	407	212	134
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5,995	12,669	12,534
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	7,260	16,261	14,704
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	6,662	14,745	14,944
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	294	717	948
Commercial | Asset-based lending
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	588	234	233
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	589	235	235
Impaired Financing Receivable, Related Allowance	161	44	26
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	588	235	235
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	21	7	10
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	553	0	1,691
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	553	0	2,550
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	728	0	8,467
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	31	0	377
Commercial | Leases
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	2,440	375	2,441
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	2,444	375	2,443
Impaired Financing Receivable, Related Allowance	215	116	107
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,539	388	2,561
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	91	14	128
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	817	0	873
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	817	0	873
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	862	0	939
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	38	0	56
Commercial real estate | Construction
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,607	0	5,302
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	2,408	0	5,302
Impaired Financing Receivable, Related Allowance	94	0	86
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,319	0	5,368
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	93	0	164
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,504	1,995	4,003
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,504	1,995	4,003
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,524	2,273	4,161
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	49	94	81
Commercial real estate | Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	2,620	1,283
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0	2,620	1,283
Impaired Financing Receivable, Related Allowance	0	44	1
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0	2,670	1,303
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	0	80	47
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,968	3,864	3,034
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	4,217	8,088	3,503
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	4,110	4,316	3,371
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	136	408	142
Commercial real estate | Office
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	2,225	1,697	2,687
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	2,291	2,361	2,697
Impaired Financing Receivable, Related Allowance	570	182	324
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,280	1,722	2,797
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	94	79	137
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,400	4,980	3,994
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	3,585	6,243	5,921
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	3,565	4,978	4,002
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	147	260	323
Commercial real estate | Industrial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	408	6,855	5,207
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	408	7,338	5,843
Impaired Financing Receivable, Related Allowance	75	1,388	1,810
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	415	7,069	7,804
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	19	284	421
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,440	3,508	2,129
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	2,729	3,827	2,436
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	2,885	3,574	2,828
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	183	200	274
Commercial real estate | Retail
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	5,932	6,605	1,750
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	6,072	6,623	1,834
Impaired Financing Receivable, Related Allowance	158	240	170
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	5,998	6,668	2,039
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	191	160	101
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,978	805	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,988	913	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	2,008	936	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	103	36	0
Commercial real estate | Multi-family
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,239	1,266	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	1,239	1,266	0
Impaired Financing Receivable, Related Allowance	8	8	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	1,250	1,134	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	33	29	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	569	89	1,903
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	653	174	1,987
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	571	109	1,825
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	23	5	84
Commercial real estate | Mixed use and other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,537	5,437	3,812
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	1,695	5,511	4,010
Impaired Financing Receivable, Related Allowance	263	605	592
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	1,580	5,452	4,038
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	60	198	195
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5,546	5,164	6,815
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	6,267	5,712	7,388
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	5,745	5,300	6,912
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	241	236	397
Home equity
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	1,511	2,373	1,961
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	1,721	2,457	1,873
Impaired Financing Receivable, Related Allowance	691	964	1,233
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	1,528	2,404	1,969
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	53	63	75
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	6,218	6,936	8,033
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	9,523	9,108	10,483
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	7,231	7,736	8,830
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	339	320	475
Residential real estate
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	5,842	5,942	5,752
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	6,154	6,428	6,327
Impaired Financing Receivable, Related Allowance	758	1,166	849
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	5,842	5,807	5,816
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	177	190	261
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	15,421	11,098	11,983
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	17,859	13,077	14,124
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	15,726	11,125	12,041
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	575	445	622
Consumer and other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	223	192	117
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	224	192	121
Impaired Financing Receivable, Related Allowance	34	192	100
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	225	194	131
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	10	8	7
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	321	410	378
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	433	520	489
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	334	428	393
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	$ 16	$ 21	$ 26

Allowance for Loan Losses, Al57

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Narrative) (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)contracts	Sep. 30, 2016USD ($)contracts	Sep. 30, 2017USD ($)contracts	Sep. 30, 2016USD ($)contracts	Sep. 30, 2017USD ($)Loan	Sep. 30, 2016USD ($)Loan	Dec. 31, 2016USD ($)
Financing Receivable, Allowance for Credit Losses [Line Items]
TDRs, number	5	2	13	15	19	17
Allowance for loan losses related to impaired loans	$ 7,218,000	$ 6,836,000	$ 7,218,000	$ 6,836,000	$ 7,218,000	$ 6,836,000	$ 6,377,000
TDRs, Additions	$ 1,663,000	$ 71,000	$ 5,386,000	$ 9,449,000	8,834,000	9,650,000
Weighted average extension term	36 months	22 months	36 months	6 months
Weighted average stated interest rate, basis points	2.25%	1.50%	1.88%	0.30%
Loan forgiveness	$ 73,000	$ 0	$ 73,000	$ 300,000
Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
TDRs	33,183,000	44,276,000	$ 33,183,000	44,276,000	33,183,000	$ 44,276,000	$ 41,708,000
TDRs, number | contracts			78
Allowance for loan losses related to impaired loans	1,200,000		$ 1,200,000		1,200,000
Interest income, passage of time	68,000	$ 98,000	172,000	$ 323,000
Residential Real Estate | Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Foreclosed residential properties	7,900,000		7,900,000		7,900,000
In process other real estate owned	$ 12,100,000		$ 12,100,000		$ 12,100,000

Allowance for Loan Losses, Al58

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of the Post-Modification Balance of TDRs) (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)contracts	Sep. 30, 2016USD ($)contracts	Sep. 30, 2017USD ($)contracts	Sep. 30, 2016USD ($)contracts	Sep. 30, 2017USD ($)Loan	Sep. 30, 2016USD ($)Loan
Financing Receivable, Modifications [Line Items]
TDRs, number	5	2	13	15	19	17
TDRs, Additions	$ 1,663	$ 71	$ 5,386	$ 9,449	$ 8,834	$ 9,650
Extension at Below Market Terms
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	1	2	9	14
TDRs, Additions	$ 186	$ 71	$ 3,909	$ 9,289
Reduction of Interest Rate
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	2	1	7	6
TDRs, Additions	$ 255	$ 43	$ 2,589	$ 7,779
Modification to Interest Only Payments
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	3	0	3	1
TDRs, Additions	$ 1,408	$ 0	$ 1,408	$ 380
Forgiveness of Debt
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	1	0	1	1
TDRs, Additions	$ 69	$ 0	$ 69	$ 275
Residential real estate and other
Financing Receivable, Modifications [Line Items]
TDRs, number	2	1	8	3	12	3
TDRs, Additions	$ 255	$ 43	$ 2,638	$ 583	$ 3,137	$ 583
Residential real estate and other | Extension at Below Market Terms
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	1	1	7	2
TDRs, Additions	$ 186	$ 43	$ 2,569	$ 423
Residential real estate and other | Reduction of Interest Rate
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	2	1	7	3
TDRs, Additions	$ 255	$ 43	$ 2,589	$ 583
Residential real estate and other | Modification to Interest Only Payments
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	1
TDRs, Additions	$ 0	$ 0	$ 0	$ 380
Residential real estate and other | Forgiveness of Debt
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	1	0	1	0
TDRs, Additions	$ 69	$ 0	$ 69	$ 0
Commercial, industrial and other | Commercial
Financing Receivable, Modifications [Line Items]
TDRs, number	3	1	4	3	4	3
TDRs, Additions	$ 1,408	$ 28	$ 1,503	$ 345	$ 1,503	$ 345
Commercial, industrial and other | Commercial | Extension at Below Market Terms
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	1	1	3
TDRs, Additions	$ 0	$ 28	$ 95	$ 345
Commercial, industrial and other | Commercial | Reduction of Interest Rate
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Commercial, industrial and other | Commercial | Modification to Interest Only Payments
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	3	0	3	0
TDRs, Additions	$ 1,408	$ 0	$ 1,408	$ 0
Commercial, industrial and other | Commercial | Forgiveness of Debt
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	1
TDRs, Additions	$ 0	$ 0	$ 0	$ 275
Office | Commercial real estate
Financing Receivable, Modifications [Line Items]
TDRs, number	0	0	0	1	0	1
TDRs, Additions	$ 0	$ 0	$ 0	$ 450	$ 0	$ 450
Office | Commercial real estate | Extension at Below Market Terms
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	1
TDRs, Additions	$ 0	$ 0	$ 0	$ 450
Office | Commercial real estate | Reduction of Interest Rate
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Office | Commercial real estate | Modification to Interest Only Payments
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Office | Commercial real estate | Forgiveness of Debt
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Industrial | Commercial real estate
Financing Receivable, Modifications [Line Items]
TDRs, number	0	0	0	6	0	6
TDRs, Additions	$ 0	$ 0	$ 0	$ 7,921	$ 0	$ 7,921
Industrial | Commercial real estate | Extension at Below Market Terms
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	6
TDRs, Additions	$ 0	$ 0	$ 0	$ 7,921
Industrial | Commercial real estate | Reduction of Interest Rate
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	3
TDRs, Additions	$ 0	$ 0	$ 0	$ 7,196
Industrial | Commercial real estate | Modification to Interest Only Payments
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Industrial | Commercial real estate | Forgiveness of Debt
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Mixed use and other | Commercial real estate
Financing Receivable, Modifications [Line Items]
TDRs, number	0	0	1	2	1	4
TDRs, Additions	$ 0	$ 0	$ 1,245	$ 150	$ 1,245	$ 351
Mixed use and other | Commercial real estate | Extension at Below Market Terms
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	1	2
TDRs, Additions	$ 0	$ 0	$ 1,245	$ 150
Mixed use and other | Commercial real estate | Reduction of Interest Rate
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Mixed use and other | Commercial real estate | Modification to Interest Only Payments
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0
Mixed use and other | Commercial real estate | Forgiveness of Debt
Financing Receivable, Modifications [Line Items]
TDRs, number | contracts	0	0	0	0
TDRs, Additions	$ 0	$ 0	$ 0	$ 0

Allowance for Loan Losses, Al59

Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of TDRs Subsequent Default Under the Restructured Terms) (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)Loancontracts	Sep. 30, 2016USD ($)Loancontracts	Sep. 30, 2017USD ($)Loancontracts	Sep. 30, 2016USD ($)Loancontracts	Sep. 30, 2017USD ($)Loan	Sep. 30, 2016USD ($)Loan
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count	5	2	13	15	19	17
Total, Balance	$ 1,663	$ 71	$ 5,386	$ 9,449	$ 8,834	$ 9,650
Subsequent Default, Count | Loan	2	5	3	7
Subsequent Default, Balance	$ 1,297	$ 1,191	$ 1,529	$ 1,392
Commercial | Commercial, industrial and other
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count	3	1	4	3	4	3
Total, Balance	$ 1,408	$ 28	$ 1,503	$ 345	$ 1,503	$ 345
Subsequent Default, Count | Loan	0	0	0	0
Subsequent Default, Balance	$ 0	$ 0	$ 0	$ 0
Commercial | Leases
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count | Loan					2	0
Total, Balance					$ 2,949	$ 0
Subsequent Default, Count | Loan	0	0	0	0
Subsequent Default, Balance	$ 0	$ 0	$ 0	$ 0
Commercial real estate | Office
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count	0	0	0	1	0	1
Total, Balance	$ 0	$ 0	$ 0	$ 450	$ 0	$ 450
Subsequent Default, Count | Loan	0	1	0	1
Subsequent Default, Balance	$ 0	$ 450	$ 0	$ 450
Commercial real estate | Industrial
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count	0	0	0	6	0	6
Total, Balance	$ 0	$ 0	$ 0	$ 7,921	$ 0	$ 7,921
Subsequent Default, Count | Loan	0	3	0	3
Subsequent Default, Balance	$ 0	$ 725	$ 0	$ 725
Commercial real estate | Mixed use and other
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count	0	0	1	2	1	4
Total, Balance	$ 0	$ 0	$ 1,245	$ 150	$ 1,245	$ 351
Subsequent Default, Count | Loan	1	1	1	3
Subsequent Default, Balance	$ 1,245	$ 16	$ 1,245	$ 217
Residential real estate and other
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]
Total, Count	2	1	8	3	12	3
Total, Balance	$ 255	$ 43	$ 2,638	$ 583	$ 3,137	$ 583
Subsequent Default, Count | Loan	1	0	2	0
Subsequent Default, Balance	$ 52	$ 0	$ 284	$ 0

Goodwill And Other Intangible60

Goodwill And Other Intangible Assets (Goodwill Assets by Business Segment) (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 498,587
Goodwill Acquired	999
Impairment Loss	0
Goodwill Adjustments	2,435
Ending balance	502,021
Community banking
Goodwill [Roll Forward]
Beginning balance	427,781
Goodwill Acquired	999
Impairment Loss	0
Goodwill Adjustments	685
Ending balance	429,465
Specialty finance
Goodwill [Roll Forward]
Beginning balance	38,692
Goodwill Acquired	0
Impairment Loss	0
Goodwill Adjustments	1,750
Ending balance	40,442
Wealth management
Goodwill [Roll Forward]
Beginning balance	32,114
Goodwill Acquired	0
Impairment Loss	0
Goodwill Adjustments	0
Ending balance	$ 32,114

Goodwill And Other Intangible61

Goodwill And Other Intangible Assets (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Indefinite-lived Intangible Assets [Line Items]
Goodwill increase due to foreign currency translation adjustments			$ 2,435
Amortization of other intangible assets	$ 1,068	$ 1,085	3,373	$ 3,631
Community banking
Indefinite-lived Intangible Assets [Line Items]
Goodwill increase			1,700
Goodwill increase due to foreign currency translation adjustments			$ 685
Community banking | Core deposit intangibles
Indefinite-lived Intangible Assets [Line Items]
Amortization period in years, other intangible assets			10 years
Specialty finance
Indefinite-lived Intangible Assets [Line Items]
Goodwill increase due to foreign currency translation adjustments			$ 1,750
Specialty finance | Customer list intangibles
Indefinite-lived Intangible Assets [Line Items]
Amortization period in years, other intangible assets			18 years
Wealth management
Indefinite-lived Intangible Assets [Line Items]
Goodwill increase due to foreign currency translation adjustments			$ 0
Wealth management | Customer list intangibles
Indefinite-lived Intangible Assets [Line Items]
Amortization period in years, other intangible assets			10 years

Goodwill And Other Intangible62

Goodwill And Other Intangible Assets (Summary of Finite-Lived Intangible Assets) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Total other intangible assets, net	$ 18,651	$ 21,851	$ 20,736
Core deposit intangibles | Community banking
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	37,272	37,272	34,998
Accumulated amortization	(24,550)	(21,614)	(20,598)
Net carrying amount	12,722	15,658	14,400
Customer list intangibles | Specialty finance
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,972	1,800	1,800
Accumulated amortization	(1,258)	(1,159)	(1,129)
Net carrying amount	714	641	671
Customer list and other intangibles | Wealth management
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	7,940	7,940	7,940
Accumulated amortization	(2,725)	(2,388)	(2,275)
Net carrying amount	$ 5,215	$ 5,552	$ 5,665

Goodwill And Other Intangible63

Goodwill And Other Intangible Assets (Estimated Amortization) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Actual in nine months ended September 30, 2017	$ 1,068	$ 1,085	$ 3,373	$ 3,631
Estimated remaining in 2017	1,027		1,027
Estimated—2018	3,796		3,796
Estimated—2019	3,223		3,223
Estimated—2020	2,597		2,597
Estimated—2021	$ 2,056		$ 2,056

Deposits (Detail)

Deposits (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Balance:
Non-interest bearing	$ 6,502,409	$ 5,927,377	$ 5,711,042
NOW and interest bearing demand deposits	2,273,025	2,624,442	2,552,611
Wealth management deposits	2,171,758	2,209,617	2,283,233
Money market	4,607,995	4,441,811	4,421,631
Savings	2,673,201	2,180,482	1,977,661
Time certificates of deposit	4,666,675	4,274,903	4,201,477
Total deposits	$ 22,895,063	$ 21,658,632	$ 21,147,655
Mix:
Non-interest bearing	28.00%	27.00%	27.00%
NOW and interest bearing demand deposits	10.00%	12.00%	12.00%
Wealth management deposits	10.00%	10.00%	11.00%
Money market	20.00%	21.00%	21.00%
Savings	12.00%	10.00%	9.00%
Time certificates of deposit	20.00%	20.00%	20.00%
Total deposits	100.00%	100.00%	100.00%

FHLB Advances, Other Borrowin65

FHLB Advances, Other Borrowings and Subordinated Notes (Summary of Debt) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Debt Disclosure [Abstract]
FHLB advances	$ 468,962	$ 153,831	$ 419,632
Other borrowings:
Notes payable	41,216	52,445	56,191
Short-term borrowings	19,959	61,809	33,173
Other	49,502	18,154	18,360
Secured borrowings	141,003	130,078	133,642
Total other borrowings	251,680	262,486	241,366
Subordinated notes	139,052	138,971	138,943
Total FHLB advances, other borrowings and subordinated notes	$ 859,694	$ 555,288	$ 799,941

FHLB Advances, Other Borrowin66

FHLB Advances, Other Borrowings and Subordinated Notes (Narrative) (Details) CAD in Millions	1 Months Ended	9 Months Ended
	Dec. 31, 2015CAD	Sep. 30, 2017USD ($)Rate	Dec. 31, 2016USD ($)	Dec. 31, 2016CAD	Sep. 30, 2016USD ($)	Jun. 15, 2015USD ($)	Dec. 31, 2014CAD
Debt Instrument [Line Items]
Notes payable		$ 41,216,000	$ 52,445,000		$ 56,191,000
Loan agreement with unaffiliated banks		150,000,000
Short-term borrowings		19,959,000	61,809,000		33,173,000
Other		49,502,000	18,154,000		18,360,000
Secured borrowings		141,003,000	130,078,000		133,642,000
Subordinated notes		139,052,000	138,971,000		138,943,000
Term Facility
Debt Instrument [Line Items]
Notes payable		41,200,000	52,400,000		56,200,000	$ 75,000,000
Revolving Credit Facility
Debt Instrument [Line Items]
Notes payable		0	0		0
Maximum borrowing capacity		$ 75,000,000
Line of credit facility, Unused capacity, Commitment fee percentage | Rate		0.20%
Securities sold under repurchase agreements
Debt Instrument [Line Items]
Securities sold under agreements to repurchase		$ 20,000,000	61,800,000		33,200,000
Pledged financial instruments		60,000,000
Fixed Rate Promissory Note
Debt Instrument [Line Items]
Other		$ 49,300,000	17,700,000		17,800,000
Contractual rate at 9/30/2017		3.36%
Non Recourse Debt
Debt Instrument [Line Items]
Other		$ 225,000	447,000		519,000
Secured Debt
Debt Instrument [Line Items]
Secured borrowings		$ 12,700,000
Subordinated Debt
Debt Instrument [Line Items]
Contractual rate at 9/30/2017		5.00%
Receivables Purchase Agreement | Secured Debt
Debt Instrument [Line Items]
Contractual rate at 9/30/2017		1.9094%
Secured borrowings		$ 128,300,000	$ 119,000,000	CAD 160	$ 121,900,000		CAD 150
Additional amount paid by third party | CAD	CAD 10
Base Rate Loan | Base Rate | Term Facility
Debt Instrument [Line Items]
Basis spread on variable rate		0.75%
Base Rate Loan | Base Rate | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%
Base Rate Loan | Federal Funds Rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.50%
Base Rate Loan | Eurodollar Rate
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Eurodollar Rate Loan | Eurodollar Rate | Term Facility
Debt Instrument [Line Items]
Basis spread on variable rate		1.75%
Eurodollar Rate Loan | Eurodollar Rate | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate		1.50%

FHLB Advances, Other Borrowin67

FHLB Advances, Other Borrowings and Subordinated Notes (Summary of Pledged Securities Related to Securities Sold Under Repurchase Agreements) (Details) - Securities sold under repurchase agreements - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Financial Instruments Owned and Pledged as Collateral [Line Items]
Pledged financial instruments	$ 60,000
Securities sold under agreements to repurchase	20,000	$ 61,800	$ 33,200
Overnight Sweep Collateral
Financial Instruments Owned and Pledged as Collateral [Line Items]
Pledged financial instruments	59,992
Excess collateral	40,033
Securities sold under agreements to repurchase	19,959
Overnight Sweep Collateral | Available-for-sale securities pledged | U.S. Treasury
Financial Instruments Owned and Pledged as Collateral [Line Items]
Pledged financial instruments	24,830
Overnight Sweep Collateral | Available-for-sale securities pledged | Mortgage-backed securities
Financial Instruments Owned and Pledged as Collateral [Line Items]
Pledged financial instruments	10,162
Overnight Sweep Collateral | Held-to-maturity securities pledged | U.S. Government agencies
Financial Instruments Owned and Pledged as Collateral [Line Items]
Pledged financial instruments	$ 25,000

Junior Subordinated Debenture68

Junior Subordinated Debentures (Narrative) (Detail)	Jan. 22, 2016USD ($)	Sep. 30, 2017USD ($)trustRate	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Jan. 31, 2016USD ($)	Aug. 31, 2005USD ($)
Subordinated Borrowing [Line Items]
Percentage ownership interest in subsidiary trusts		100.00%
Number of unconsolidated subsidiary trusts | trust		11
Common securities, approximate percentage of junior subordinated debentures		3.00%
Trust preferred securities, approximate percentage of junior subordinated debentures		97.00%
Junior subordinated debentures		$ 253,566,000	$ 253,566,000	$ 253,566,000
Gains on early extinguishment of debt		0	$ 4,305,000
Junior Subordinated Debt
Subordinated Borrowing [Line Items]
Junior subordinated debentures		$ 253,566,000
Debt, weighted average interest rate | Rate		3.52%
Period of deferred payment, not to exceed		60 months
Tier one risk based capital		$ 0
Tier two risk based capital		245,500,000
Junior Subordinated Debt | Wintrust Capital Trust VIII
Subordinated Borrowing [Line Items]
Trust preferred securities		25,000,000			$ 15,000,000	$ 40,000,000
Junior subordinated debentures		$ 26,238,000			$ 15,000,000
Gains on early extinguishment of debt	$ 4,300,000

Junior Subordinated Debenture69

Junior Subordinated Debentures (Summary of Junior Subordinated Debentures) (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jan. 31, 2016	Aug. 31, 2005
Subordinated Borrowing [Line Items]
Junior Subordinated Debentures	$ 253,566,000	$ 253,566,000	$ 253,566,000
Junior Subordinated Debt
Subordinated Borrowing [Line Items]
Junior Subordinated Debentures	$ 253,566,000
Debt, weighted average interest rate	3.52%
Junior Subordinated Debt | Wintrust Capital Trust III
Subordinated Borrowing [Line Items]
Common Securities	$ 774,000
Trust Preferred Securities	25,000,000
Junior Subordinated Debentures	$ 25,774,000
Rate Structure	L+3.25
Contractual rate at 9/30/2017	4.55%
Junior Subordinated Debt | Wintrust Capital Trust III | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	3.25%
Junior Subordinated Debt | Wintrust Statutory Trust IV
Subordinated Borrowing [Line Items]
Common Securities	$ 619,000
Trust Preferred Securities	20,000,000
Junior Subordinated Debentures	$ 20,619,000
Rate Structure	L+2.80
Contractual rate at 9/30/2017	4.14%
Junior Subordinated Debt | Wintrust Statutory Trust IV | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	2.80%
Junior Subordinated Debt | Wintrust Statutory Trust V
Subordinated Borrowing [Line Items]
Common Securities	$ 1,238,000
Trust Preferred Securities	40,000,000
Junior Subordinated Debentures	$ 41,238,000
Rate Structure	L+2.60
Contractual rate at 9/30/2017	3.94%
Junior Subordinated Debt | Wintrust Statutory Trust V | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	2.60%
Junior Subordinated Debt | Wintrust Capital Trust VII
Subordinated Borrowing [Line Items]
Common Securities	$ 1,550,000
Trust Preferred Securities	50,000,000
Junior Subordinated Debentures	$ 51,550,000
Rate Structure	L+1.95
Contractual rate at 9/30/2017	3.27%
Junior Subordinated Debt | Wintrust Capital Trust VII | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	1.95%
Junior Subordinated Debt | Wintrust Capital Trust VIII
Subordinated Borrowing [Line Items]
Common Securities	$ 1,238,000
Trust Preferred Securities	25,000,000			$ 15,000,000	$ 40,000,000
Junior Subordinated Debentures	$ 26,238,000			$ 15,000,000
Rate Structure	L+1.45
Contractual rate at 9/30/2017	2.79%
Junior Subordinated Debt | Wintrust Capital Trust VIII | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	1.45%
Junior Subordinated Debt | Wintrust Capital Trust IX
Subordinated Borrowing [Line Items]
Common Securities	$ 1,547,000
Trust Preferred Securities	50,000,000
Junior Subordinated Debentures	$ 51,547,000
Rate Structure	L+1.63
Contractual rate at 9/30/2017	2.95%
Junior Subordinated Debt | Wintrust Capital Trust IX | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	1.63%
Junior Subordinated Debt | Northview Capital Trust I
Subordinated Borrowing [Line Items]
Common Securities	$ 186,000
Trust Preferred Securities	6,000,000
Junior Subordinated Debentures	$ 6,186,000
Rate Structure	L+3.00
Contractual rate at 9/30/2017	4.31%
Junior Subordinated Debt | Northview Capital Trust I | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	3.00%
Junior Subordinated Debt | Town Bankshares Capital Trust I
Subordinated Borrowing [Line Items]
Common Securities	$ 186,000
Trust Preferred Securities	6,000,000
Junior Subordinated Debentures	$ 6,186,000
Rate Structure	L+3.00
Contractual rate at 9/30/2017	4.31%
Junior Subordinated Debt | Town Bankshares Capital Trust I | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	3.00%
Junior Subordinated Debt | First Northwest Capital Trust I
Subordinated Borrowing [Line Items]
Common Securities	$ 155,000
Trust Preferred Securities	5,000,000
Junior Subordinated Debentures	$ 5,155,000
Rate Structure	L+3.00
Contractual rate at 9/30/2017	4.34%
Junior Subordinated Debt | First Northwest Capital Trust I | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	3.00%
Junior Subordinated Debt | Suburban Illinois Capital Trust II
Subordinated Borrowing [Line Items]
Common Securities	$ 464,000
Trust Preferred Securities	15,000,000
Junior Subordinated Debentures	$ 15,464,000
Rate Structure	L+1.75
Contractual rate at 9/30/2017	3.07%
Junior Subordinated Debt | Suburban Illinois Capital Trust II | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	1.75%
Junior Subordinated Debt | Community Financial Shares Statutory Trust II
Subordinated Borrowing [Line Items]
Common Securities	$ 109,000
Trust Preferred Securities	3,500,000
Junior Subordinated Debentures	$ 3,609,000
Rate Structure	L+1.62
Contractual rate at 9/30/2017	2.94%
Junior Subordinated Debt | Community Financial Shares Statutory Trust II | London Interbank Offered Rate (LIBOR)
Subordinated Borrowing [Line Items]
Rate Structure, incremental interest rate over base rate	1.62%

Segment Information (Narrative)

Segment Information (Narrative) (Detail)	9 Months Ended
	Sep. 30, 2017segmentsubsidiary
Segment Reporting Information [Line Items]
Number of reportable segments	3
Number of subsidiaries | subsidiary	15
Community banking
Segment Reporting Information [Line Items]
Number of reportable segments	1

Segment Information (Summary of

Segment Information (Summary of Segment Information) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net interest income	$ 215,988	$ 184,636	$ 612,977	$ 531,415
Net interest income, Change in Contribution	$ 31,352		$ 81,562
Net interest income, Change in Contribution Percentage	17.00%		15.00%
Non-interest income	$ 79,731	86,604	$ 238,468	240,155
Non-interest income, Change in Contribution	$ (6,873)		$ (1,687)
Non-interest income, Change in Contribution Percentage	(8.00%)		(1.00%)
Net revenue	$ 295,719	271,240	$ 851,445	771,570
Net revenue, Change in Contribution	$ 24,479		$ 79,875
Net revenue, Change in Contribution Percentage	9.00%		10.00%
Segment profit	$ 65,626	53,115	$ 188,901	152,267
Segment profit, Change in Contribution	$ 12,511		$ 36,634
Segment profit, Change in Contribution Percentage	24.00%		24.00%
Segment assets	$ 27,358,162	25,321,759	$ 27,358,162	25,321,759	$ 25,668,553
Segment assets, Change in Contribution	$ 2,036,403
Segment assets, Change in Contribution Percentage	8.00%
Community banking
Segment Reporting Information [Line Items]
Segment profit	$ 44,799	37,527	128,502	106,860
Segment profit, Change in Contribution	$ 7,272		$ 21,642
Segment profit, Change in Contribution Percentage	19.00%		20.00%
Segment assets	$ 22,426,049	21,019,002	$ 22,426,049	21,019,002
Segment assets, Change in Contribution	$ 1,407,047
Segment assets, Change in Contribution Percentage	7.00%
Specialty finance
Segment Reporting Information [Line Items]
Segment profit	$ 17,043	12,767	47,990	36,283
Segment profit, Change in Contribution	$ 4,276		$ 11,707
Segment profit, Change in Contribution Percentage	33.00%		32.00%
Segment assets	$ 4,305,960	3,702,241	$ 4,305,960	3,702,241
Segment assets, Change in Contribution	$ 603,719
Segment assets, Change in Contribution Percentage	16.00%
Wealth management
Segment Reporting Information [Line Items]
Segment profit	$ 3,784	2,821	12,409	9,124
Segment profit, Change in Contribution	$ 963		$ 3,285
Segment profit, Change in Contribution Percentage	34.00%		36.00%
Segment assets	$ 626,153	600,516	$ 626,153	600,516
Segment assets, Change in Contribution	$ 25,637
Segment assets, Change in Contribution Percentage	4.00%
Operating Segments
Segment Reporting Information [Line Items]
Net interest income	$ 211,584	180,537	599,538	518,884
Net interest income, Change in Contribution	$ 31,047		$ 80,654
Net interest income, Change in Contribution Percentage	17.00%		16.00%
Non-interest income	$ 89,240	95,001	$ 266,215	264,981
Non-interest income, Change in Contribution	$ (5,761)		$ 1,234
Non-interest income, Change in Contribution Percentage	(6.00%)		0.00%
Net revenue	$ 300,824	275,538	$ 865,753	783,865
Net revenue, Change in Contribution	$ 25,286		$ 81,888
Net revenue, Change in Contribution Percentage	9.00%		10.00%
Operating Segments | Community banking
Segment Reporting Information [Line Items]
Net interest income	$ 176,526	150,159	$ 499,135	434,108
Net interest income, Change in Contribution	$ 26,367		$ 65,027
Net interest income, Change in Contribution Percentage	18.00%		15.00%
Non-interest income	$ 52,554	62,730	$ 160,277	169,210
Non-interest income, Change in Contribution	$ (10,176)		$ (8,933)
Non-interest income, Change in Contribution Percentage	(16.00%)		(5.00%)
Net revenue	$ 229,080	212,889	$ 659,412	603,318
Net revenue, Change in Contribution	$ 16,191		$ 56,094
Net revenue, Change in Contribution Percentage	8.00%		9.00%
Operating Segments | Specialty finance
Segment Reporting Information [Line Items]
Net interest income	$ 30,501	25,543	$ 85,871	71,075
Net interest income, Change in Contribution	$ 4,958		$ 14,796
Net interest income, Change in Contribution Percentage	19.00%		21.00%
Non-interest income	$ 16,315	12,226	$ 44,192	37,111
Non-interest income, Change in Contribution	$ 4,089		$ 7,081
Non-interest income, Change in Contribution Percentage	33.00%		19.00%
Net revenue	$ 46,816	37,769	$ 130,063	108,186
Net revenue, Change in Contribution	$ 9,047		$ 21,877
Net revenue, Change in Contribution Percentage	24.00%		20.00%
Operating Segments | Wealth management
Segment Reporting Information [Line Items]
Net interest income	$ 4,557	4,835	$ 14,532	13,701
Net interest income, Change in Contribution	$ (278)		$ 831
Net interest income, Change in Contribution Percentage	(6.00%)		6.00%
Non-interest income	$ 20,371	20,045	$ 61,746	58,660
Non-interest income, Change in Contribution	$ 326		$ 3,086
Non-interest income, Change in Contribution Percentage	2.00%		5.00%
Net revenue	$ 24,928	24,880	$ 76,278	72,361
Net revenue, Change in Contribution	$ 48		$ 3,917
Net revenue, Change in Contribution Percentage	0.00%		5.00%
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net interest income	$ 4,404	4,099	$ 13,439	12,531
Net interest income, Change in Contribution	$ 305		$ 908
Net interest income, Change in Contribution Percentage	7.00%		7.00%
Non-interest income	$ (9,509)	(8,397)	$ (27,747)	(24,826)
Non-interest income, Change in Contribution	$ (1,112)		$ (2,921)
Non-interest income, Change in Contribution Percentage	(13.00%)		(12.00%)
Net revenue	$ (5,105)	$ (4,298)	$ (14,308)	$ (12,295)
Net revenue, Change in Contribution	$ (807)		$ (2,013)
Net revenue, Change in Contribution Percentage	(19.00%)		(16.00%)

Derivative Financial Instrume72

Derivative Financial Instruments (Schedule Of Fair Value Of Derivative Financial Instruments) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Derivative [Line Items]
Derivative assets	$ 48,198	$ 56,394	$ 88,828
Derivative liabilities	35,773	39,839	87,948
Interest Rate Contract
Derivative [Line Items]
Derivative assets	45,168	49,213	80,203
Derivative liabilities	34,035	37,665	80,113
Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	10,679	10,239	726
Derivative liabilities	53	0	914
Designated as Hedging Instrument | Interest Rate Contract | Cash Flow Hedging
Derivative [Line Items]
Derivative assets	8,643	8,011	549
Derivative liabilities	0	0	7
Designated as Hedging Instrument | Interest Rate Contract | Fair Value Hedging
Derivative [Line Items]
Derivative assets	2,036	2,228	177
Derivative liabilities	53	0	907
Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative assets	37,519	46,155	88,102
Derivative liabilities	35,720	39,839	87,034
Not Designated as Hedging Instrument | Interest Rate Contract
Derivative [Line Items]
Derivative assets	34,489	38,974	79,477
Derivative liabilities	33,982	37,665	79,199
Not Designated as Hedging Instrument | Interest Rate Lock Commitments
Derivative [Line Items]
Derivative assets	2,851	4,265	8,352
Derivative liabilities	1	1,325	4,060
Not Designated as Hedging Instrument | Forward Commitments to Sell Mortgage Loans
Derivative [Line Items]
Derivative assets	19	2,037	0
Derivative liabilities	1,495	0	3,505
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative [Line Items]
Derivative assets	160	879	273
Derivative liabilities	$ 242	$ 849	$ 270

Derivative Financial Instrume73

Derivative Financial Instruments (Narrative) (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)derivative_instruments	Sep. 30, 2016USD ($)derivative_instruments	Sep. 30, 2017USD ($)derivative_instruments	Sep. 30, 2016USD ($)derivative_instruments	Dec. 31, 2016derivative_instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income to interest expense in the next twelve months			$ 3,500,000
Net derivative liability position, aggregate fair value	$ 9,800,000		9,800,000
Interest Rate Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	4,900,000,000		4,900,000,000
Forward Commitments to Sell Mortgage Loans | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	773,500,000		773,500,000
Interest Rate Lock Commitments | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	409,300,000		409,300,000
Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 43,400,000		$ 43,400,000
Covered Call Options | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of derivative instruments held | derivative_instruments	0	0	0	0	0
Cash Flow Hedging | Interest Rate Contract | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on cash flow hedge ineffectiveness, net			$ 0	$ 0
Cash Flow Hedging | Cash flow hedge of variable rate deposits | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate derivatives held | derivative_instruments	4		4
Cash Flow Hedging | Interest Rate Swap, $200 million, June 2019 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 200,000,000		$ 200,000,000
Cash Flow Hedging | Interest Rate Swap, $200 million, June 2019 | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	200,000,000		200,000,000
Cash Flow Hedging | Interest Rate Swap, $250 million, July 2019 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	250,000,000		250,000,000
Cash Flow Hedging | Interest Rate Swap, $250 million, July 2019 | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	250,000,000		250,000,000
Cash Flow Hedging | Interest Rate Swap, $275 million, August 2019 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	275,000,000		275,000,000
Cash Flow Hedging | Interest Rate Swap, $275 million, August 2019 | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	275,000,000		275,000,000
Cash Flow Hedging | Interest Rate Swap, $200 million, June 2020 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	200,000,000		200,000,000
Cash Flow Hedging | Interest Rate Swap, $200 million, June 2020 | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 200,000,000		$ 200,000,000
Fair Value Hedging | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate derivatives held | derivative_instruments	11		11
Notional amount	$ 126,100,000		$ 126,100,000
Fair Value Hedging | Interest Rate Contract | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on fair value hedge ineffectiveness, net	$ 12,000	$ 35,000	$ 41,000	$ 13,000

Derivative Financial Instrume74

Derivative Financial Instruments (Schedule Of Cash Flow Hedging Instruments) (Detail) - Cash Flow Hedging - Designated as Hedging Instrument	Sep. 30, 2017USD ($)
Interest Rate Swap, $200 million, June 2019
Derivative [Line Items]
Notional Amount	$ 200,000,000
Fair Value Asset (Liability)	295,000
Interest Rate Swap, $250 million, July 2019
Derivative [Line Items]
Notional Amount	250,000,000
Fair Value Asset (Liability)	3,549,000
Interest Rate Swap, $275 million, August 2019
Derivative [Line Items]
Notional Amount	275,000,000
Fair Value Asset (Liability)	4,434,000
Interest Rate Swap, $200 million, June 2020
Derivative [Line Items]
Notional Amount	200,000,000
Fair Value Asset (Liability)	365,000
Total Interest Rate Swap
Derivative [Line Items]
Notional Amount	925,000,000
Fair Value Asset (Liability)	$ 8,643,000

Derivative Financial Instrume75

Derivative Financial Instruments (Rollforward Of Amounts In Accumulated Other Comprehensive Income Related To Interest Rate Swaps Designated As Cash Flow Hedges) (Detail) - Interest Rate Contract - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Rollforward of AOCI from Cash Flow Hedging Derivatives [Roll Forward]
Unrealized gain (loss) at beginning of period	$ 8,249	$ (3,574)	$ 6,944	$ (3,529)
Amount reclassified from accumulated other comprehensive loss to interest expense on deposits and junior subordinated debentures	14	1,065	1,051	2,620
Amount of (loss) gain recognized in other comprehensive income	380	1,708	648	108
Unrealized gain (loss) at end of period	$ 8,643	$ (801)	$ 8,643	$ (801)

Derivative Financial Instrume76

Derivative Financial Instruments (Derivatives Used To Hedge Changes In Fair Value Attributable To Interest Rate Risk) (Detail) - Fair Value Hedging - Designated as Hedging Instrument - Interest Rate Contract - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (64)	$ 269	$ (245)	$ (614)
Amount of Gain or (Loss) Recognized in Income on Hedged Item	76	(234)	286	627
Income Statement Gain/(Loss) due to Hedge Ineffectiveness	$ 12	$ 35	$ 41	$ 13

Derivative Financial Instrume77

Derivative Financial Instruments (Summary Amounts Included In Consolidated Statement Of Income Related To Derivatives) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest Rate Swaps and Caps | Trading (losses) gains, net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	$ (94)	$ (395)	$ (762)	$ (751)
Mortgage Banking Derivatives | Mortgage banking revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	708	(2,215)	1,398	(3,058)
Covered Call Options | Fees from covered call options
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	1,143	3,633	2,792	9,994
Foreign Exchange Contract | Trading (losses) gains, net
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) on derivative instruments	$ (23)	$ (26)	$ (115)	$ (262)

Derivative Financial Instrume78

Derivative Financial Instruments (Derivative Asset and Liability Balance Sheet Offsetting) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Offsetting Assets [Line Items]
Net amount presented in the Statements of Financial Condition	$ 48,198	$ 56,394	$ 88,828
Derivative Liabilities
Net amount presented in the Statements of Financial Condition	35,773	39,839	87,948
Interest Rate Contract
Offsetting Assets [Line Items]
Gross Amounts Recognized	45,168	49,213	80,203
Less: Amounts offset in the Statements of Financial Condition	0	0	0
Net amount presented in the Statements of Financial Condition	45,168	49,213	80,203
Offsetting Derivative Positions	(16,213)	(14,441)	(958)
Collateral Posted	(2,950)	(8,530)	0
Net Credit Exposure	26,005	26,242	79,245
Derivative Liabilities
Gross Amounts Recognized	34,035	37,665	80,113
Less: Amounts offset in the Statements of Financial Condition	0	0	0
Net amount presented in the Statements of Financial Condition	34,035	37,665	80,113
Offsetting Derivative Positions	(16,213)	(14,441)	(958)
Collateral Posted	(17,130)	(12,400)	(79,155)
Net Credit Exposure	$ 692	$ 10,824	0
Collateral posted which resulted in excess collateral with counterparties			$ 86,000

Fair Values of Assets and Lia79

Fair Values of Assets and Liabilities (Narrative) (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)$ / Loan	Dec. 31, 2016USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	$ 1,650,096,000	$ 1,665,903,000	$ 1,724,667,000
Loans held-for-investment	17,603,000	29,414,000
Derivative assets	88,828,000	48,198,000	56,394,000
Mortgage loans held-for-sale	559,634,000	370,282,000	418,374,000
Impaired loans—collateral based	90,540,000	$ 78,594,000	90,516,000
Other real estate owned, including covered other real estate owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Appraisal adjustment - cost of sale		10.00%
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	1,650,096,000	$ 1,665,903,000	1,724,667,000
MSRs	13,901,000	29,414,000	19,103,000
Remaining contractual principal balance outstanding, mortgage loans held-for-sale	537,000,000	356,400,000	414,400,000
Mortgage loans held-for-sale	559,634,000	370,282,000	418,374,000
Portion at Other than Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based		21,100,000
Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	109,281,000	116,016,000	131,809,000
U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	93,683,000	159,328,000	189,152,000
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	50,782,000	36,352,000	35,248,000
Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-investment	17,603,000	29,704,000	22,137,000
MSRs	13,901,000	29,414,000	19,103,000
Derivative assets	88,828,000	48,198,000	56,394,000
Mortgage loans held-for-sale	559,634,000	370,282,000	418,374,000
Measured at fair value on a recurring basis: | Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	109,281,000	116,016,000	131,809,000
Measured at fair value on a recurring basis: | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	93,683,000	159,328,000	189,152,000
Measured at fair value on a recurring basis: | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	50,782,000	36,352,000	35,248,000
Measured at fair value on a non-recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based		57,548,000
Other real estate owned, including covered other real estate owned		40,229,000
Level 3 | Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-investment	0	29,704,000	22,137,000
MSRs	13,901,000	29,414,000	19,103,000
Derivative assets	6,037,000	1,216,000	2,291,000
Mortgage loans held-for-sale	0	$ 0	0
Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Constant prepayment rate (CPR)		9.62%
Level 3 | Measured at fair value on a recurring basis: | Minimum | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate input		3.00%
Credit loss rate		0.00%
Level 3 | Measured at fair value on a recurring basis: | Minimum | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate input		9.00%
Constant prepayment rate (CPR)		0.00%
Level 3 | Measured at fair value on a recurring basis: | Minimum | Derivatives | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pull-through rate		38.00%
Level 3 | Measured at fair value on a recurring basis: | Maximum | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate input		4.00%
Credit loss rate		3.00%
Level 3 | Measured at fair value on a recurring basis: | Maximum | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate input		15.00%
Constant prepayment rate (CPR)		47.00%
Level 3 | Measured at fair value on a recurring basis: | Maximum | Derivatives | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pull-through rate		100.00%
Level 3 | Measured at fair value on a recurring basis: | Weighted Average of Inputs | Loans held-for-investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate input		3.65%
Credit loss rate		0.94%
Level 3 | Measured at fair value on a recurring basis: | Weighted Average of Inputs | Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate input		9.97%
Constant prepayment rate (CPR)		10.50%
Range of Inputs (in dollars per loan) | $ / Loan		69
Weighted Average of Inputs (in dollars per loan) | $ / Loan		634
Level 3 | Measured at fair value on a recurring basis: | Weighted Average of Inputs | Derivatives | Discounted cash flows
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pull-through rate		88.85%
Level 3 | Measured at fair value on a recurring basis: | Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	67,208,000	$ 68,383,000	79,626,000
Level 3 | Measured at fair value on a recurring basis: | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	0	3,943,000	0
Level 3 | Measured at fair value on a recurring basis: | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, at fair value	0	0	0
Gain on transfer	2,400,000
Level 3 | Measured at fair value on a non-recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based		57,548,000
Other real estate owned, including covered other real estate owned		40,229,000
Non-performing
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held-for-sale	$ 0	$ 0	$ 0

Fair Values of Assets and Lia80

Fair Values of Assets and Liabilities (Summary of Balances of Assets and Liabilities Measured at Fair Value On A Recurring Basis) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 1,665,903	$ 1,724,667	$ 1,650,096
Trading account securities	643	1,989	1,092
Mortgage loans held-for-sale	370,282	418,374	559,634
Loans held-for-investment	29,414		17,603
Derivative assets	48,198	56,394	88,828
Derivative liabilities	35,773	39,839	87,948
U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	144,145	141,983	30,036
U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	159,328	189,152	93,683
Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	116,016	131,809	109,281
Mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,149,448	1,161,084	1,301,111
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	36,352	35,248	50,782
Measured at fair value on a recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	643	1,989	1,092
Mortgage loans held-for-sale	370,282	418,374	559,634
Loans held-for-investment	29,704	22,137	17,603
MSRs	29,414	19,103	13,901
Nonqualified deferred compensation assets	10,824	9,228	9,218
Derivative assets	48,198	56,394	88,828
Total	2,154,968	2,251,892	2,340,372
Derivative liabilities	35,773	39,839	87,948
Measured at fair value on a recurring basis: | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	144,145	141,983	30,036
Measured at fair value on a recurring basis: | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	159,328	189,152	93,683
Measured at fair value on a recurring basis: | Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	116,016	131,809	109,281
Measured at fair value on a recurring basis: | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	60,614	65,391	65,203
Measured at fair value on a recurring basis: | Mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,149,448	1,161,084	1,301,111
Measured at fair value on a recurring basis: | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	36,352	35,248	50,782
Measured at fair value on a recurring basis: | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans held-for-investment		0
Measured at fair value on a recurring basis: | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	643	1,989	1,092
Mortgage loans held-for-sale	370,282	418,374	559,634
Loans held-for-investment	0	0	17,603
MSRs	0	0	0
Nonqualified deferred compensation assets	10,824	9,228	9,218
Derivative assets	46,982	54,103	82,791
Total	2,022,308	2,128,735	2,253,226
Derivative liabilities	35,773	39,839	87,948
Measured at fair value on a recurring basis: | Level 2 | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	144,145	141,983	30,036
Measured at fair value on a recurring basis: | Level 2 | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	155,385	189,152	93,683
Measured at fair value on a recurring basis: | Level 2 | Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	47,633	52,183	42,073
Measured at fair value on a recurring basis: | Level 2 | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	60,614	65,391	65,203
Measured at fair value on a recurring basis: | Level 2 | Mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	1,149,448	1,161,084	1,301,111
Measured at fair value on a recurring basis: | Level 2 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	36,352	35,248	50,782
Measured at fair value on a recurring basis: | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account securities	0	0	0
Mortgage loans held-for-sale	0	0	0
Loans held-for-investment	29,704	22,137	0
MSRs	29,414	19,103	13,901
Nonqualified deferred compensation assets	0	0	0
Derivative assets	1,216	2,291	6,037
Total	132,660	123,157	87,146
Derivative liabilities	0	0	0
Measured at fair value on a recurring basis: | Level 3 | U.S. Treasury
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0	0
Measured at fair value on a recurring basis: | Level 3 | U.S. Government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	3,943	0	0
Measured at fair value on a recurring basis: | Level 3 | Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	68,383	79,626	67,208
Measured at fair value on a recurring basis: | Level 3 | Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0	0
Measured at fair value on a recurring basis: | Level 3 | Mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0	0
Measured at fair value on a recurring basis: | Level 3 | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 0	$ 0	$ 0

Fair Values of Assets and Lia81

Fair Values of Assets and Liabilities (Summary of Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Loans held-for- investment
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 30,173	$ 0	$ 22,137	$ 0
Net Income	(177)	0	(1,369)	0
Other comprehensive loss	0	0	0	0
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	(4,504)	0	(9,995)	0
Net transfers into/(out of) Level 3	3,858	0	16,193	0
Ending Balance	29,704	0	29,704	0
Mortgage servicing rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	27,307	13,382	19,103	9,092
Net Income	(2,107)	(519)	(10,311)	(4,809)
Other comprehensive loss		0		0
Purchases		0		0
Issuances	0	0	0	0
Settlements		0		0
Net transfers into/(out of) Level 3	0	0	0	0
Ending Balance	29,414	13,901	29,414	13,901
Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,047	9,731	2,291	7,021
Net Income	(169)	3,694	1,075	984
Other comprehensive loss	0	0	0	0
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Net transfers into/(out of) Level 3	0	0	0	0
Ending Balance	1,216	6,037	1,216	6,037
Municipal Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	77,341	69,812	79,626	68,613
Net Income		0		0
Other comprehensive loss	4,113	241	1,084	141
Purchases	0	2,184	10,879	6,458
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	(4,845)	(4,547)	(21,038)	(7,722)
Net transfers into/(out of) Level 3		0		0
Ending Balance	68,383	67,208	68,383	67,208
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	0	25,187	0	25,199
Net Income		0		0
Other comprehensive loss	0		0	12
Purchases		0		0
Issuances	0	0	0	0
Sales		(25,187)		(25,187)
Settlements		0		0
Net transfers into/(out of) Level 3	0	0	0	0
Ending Balance	0	0	0	0
U.S. Government agencies
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,110	0	0	0
Net Income	0	0	0	0
Other comprehensive loss	167	0	340	0
Purchases	0	0	0	0
Issuances	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Net transfers into/(out of) Level 3	0	0	4,283	0
Ending Balance	$ 3,943	$ 0	$ 3,943	$ 0

Fair Values of Assets and Lia82

Fair Values of Assets and Liabilities (Summary of Assets Measured at Fair Value on a Nonrecurring Basis) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	$ 78,594	$ 78,594	$ 90,516	$ 90,540
Fair Value Losses Recognized, Impaired loans—collateral based	4,259	10,589
Fair Value Losses Recognized, Other real estate owned	490	1,760
Fair Value Losses Recognized, Total	4,749	12,349
Measured at fair value on a non-recurring basis:
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	57,548	57,548
Other real estate owned, including covered other real estate owned	40,229	40,229
Total	97,777	97,777
Measured at fair value on a non-recurring basis: | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	0	0
Other real estate owned, including covered other real estate owned	0	0
Total	0	0
Measured at fair value on a non-recurring basis: | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	0	0
Other real estate owned, including covered other real estate owned	0	0
Total	0	0
Measured at fair value on a non-recurring basis: | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans—collateral based	57,548	57,548
Other real estate owned, including covered other real estate owned	40,229	40,229
Total	$ 97,777	$ 97,777

Fair Values of Assets and Lia83

Fair Values of Assets and Liabilities (Schedule of Valuation Techniques and Significant Unobservable Inputs Used to Measure Both Recurring and Non-Recurring) (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)$ / Loan	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	$ 1,665,903	$ 1,724,667	$ 1,650,096
Loans held-for-investment	29,414		17,603
Derivative assets	48,198	56,394	88,828
Impaired loans—collateral based	$ 78,594	90,516	90,540
Other real estate owned, including covered other real estate owned
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Appraisal adjustment - cost of sale	10.00%
Municipal Securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	$ 116,016	131,809	109,281
U.S. Government agencies
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	159,328	189,152	93,683
Measured at fair value on a recurring basis:
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans held-for-investment	29,704	22,137	17,603
MSRs	29,414	19,103	13,901
Derivative assets	48,198	56,394	88,828
Measured at fair value on a recurring basis: | Municipal Securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	116,016	131,809	109,281
Measured at fair value on a recurring basis: | U.S. Government agencies
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	159,328	189,152	93,683
Measured at fair value on a non-recurring basis:
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based	57,548
Other real estate owned, including covered other real estate owned	40,229
Level 3 | Measured at fair value on a recurring basis:
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans held-for-investment	29,704	22,137	0
MSRs	29,414	19,103	13,901
Derivative assets	$ 1,216	2,291	6,037
Level 3 | Measured at fair value on a recurring basis: | Loans held-for- investment
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate (CPR)	9.62%
Level 3 | Measured at fair value on a recurring basis: | Loans held-for- investment | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	3.00%
Credit loss rate	0.00%
Level 3 | Measured at fair value on a recurring basis: | Loans held-for- investment | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	4.00%
Credit loss rate	3.00%
Level 3 | Measured at fair value on a recurring basis: | Loans held-for- investment | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	3.65%
Credit loss rate	0.94%
Level 3 | Measured at fair value on a recurring basis: | Mortgage servicing rights | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	9.00%
Constant prepayment rate (CPR)	0.00%
Level 3 | Measured at fair value on a recurring basis: | Mortgage servicing rights | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	15.00%
Constant prepayment rate (CPR)	47.00%
Level 3 | Measured at fair value on a recurring basis: | Mortgage servicing rights | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	9.97%
Constant prepayment rate (CPR)	10.50%
Cost of servicing (in dollars per loan) | $ / Loan	69
Cost of servicing - delinquent (in dollars per loan) | $ / Loan	634
Level 3 | Measured at fair value on a recurring basis: | Municipal Securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	$ 68,383	79,626	67,208
Level 3 | Measured at fair value on a recurring basis: | U.S. Government agencies
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities	3,943	$ 0	$ 0
Level 3 | Measured at fair value on a non-recurring basis:
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based	57,548
Other real estate owned, including covered other real estate owned	$ 40,229
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Discount Rate | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	3.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Discount Rate | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	4.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Discount Rate | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	3.65%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Credit Spread | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit loss rate	0.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Credit Spread | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit loss rate	3.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Credit Spread | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit loss rate	0.94%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate (CPR)	9.62%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Loans held-for-investment Constant Prepayment Rate | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate (CPR)	9.62%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Discount Rate | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	9.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Discount Rate | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	15.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Discount Rate | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount rate	9.97%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Prepayment Rate | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate (CPR)	0.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Prepayment Rate | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate (CPR)	47.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Prepayment Rate | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Constant prepayment rate (CPR)	10.50%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Cost of servicing | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cost of servicing (in dollars per loan) | $ / Loan	65
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Cost of servicing | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cost of servicing (in dollars per loan) | $ / Loan	200
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Cost of servicing | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cost of servicing (in dollars per loan) | $ / Loan	69
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Cost of servicing - delinquent | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cost of servicing - delinquent (in dollars per loan) | $ / Loan	200
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Cost of servicing - delinquent | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cost of servicing - delinquent (in dollars per loan) | $ / Loan	1,000
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Mortgage Servicing Rights Cost of servicing - delinquent | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Cost of servicing - delinquent (in dollars per loan) | $ / Loan	634
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Derivatives | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull-through rate	38.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Derivatives | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull-through rate	100.00%
Discounted cash flows | Level 3 | Measured at fair value on a recurring basis: | Derivatives | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull-through rate	88.85%
Appraisal value | Level 3 | Measured at fair value on a non-recurring basis: | Impaired loans—collateral based | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Appraisal adjustment - cost of sale	10.00%
Appraisal value | Level 3 | Measured at fair value on a non-recurring basis: | Other real estate owned, including covered other real estate owned | Weighted Average of Inputs
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Appraisal adjustment - cost of sale	10.00%

Fair Values of Assets and Lia84

Fair Values of Assets and Liabilities (Summary Of Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 251,952		$ 270,045	$ 246,947		$ 275,795
Interest bearing deposits with banks	1,218,728		980,457	816,104
Available-for-sale securities	1,665,903		1,724,667	1,650,096
Held-to-maturity securities	807,036		607,602	942,666
Trading account securities	643		1,989	1,092
FHLB and FRB stock, at cost	87,192		133,494	129,630
Brokerage customer receivables	23,631		25,181	25,511
Mortgage loans held-for-sale, at fair value	370,282		418,374	559,634
Accrued interest receivable and other	580,612		593,796	660,923
FHLB advances	468,962		153,831	419,632
Other borrowings	251,680		262,486	241,366
Subordinated notes	139,052		138,971	138,943
Junior subordinated debentures	253,566		253,566	253,566
Derivative liabilities	35,773		39,839	87,948
FDIC indemnification liability	15,472	$ 15,375	16,701	17,945	$ 11,729	$ 6,100
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	251,952		270,045	246,947
Interest bearing deposits with banks	1,218,728		980,457	816,104
Available-for-sale securities	1,665,903		1,724,667	1,650,096
Held-to-maturity securities	819,340		635,705	932,767
Trading account securities	643		1,989	1,092
FHLB and FRB stock, at cost	87,192		133,494	129,630
Brokerage customer receivables	23,631		25,181	25,511
Mortgage loans held-for-sale, at fair value	370,282		418,374	559,634
Loans held-for-investment, at fair value	29,704		22,137	17,603
Loans held-for-investment, at amortized cost	20,929,678		19,739,180	19,179,598
MSRs	29,414		19,103	13,901
Nonqualified deferred compensation assets	10,824		9,228	9,218
Derivative assets	48,198		56,394	88,828
Accrued interest receivable and other	225,435		204,513	205,725
Total financial assets	25,710,924		24,240,467	23,876,654
Non-maturity deposits	18,228,388		17,383,729	16,946,178
Deposits with stated maturities	4,666,675		4,274,903	4,201,477
FHLB advances	468,962		153,831	419,632
Other borrowings	251,680		262,486	241,366
Subordinated notes	139,052		138,971	138,943
Junior subordinated debentures	253,566		253,566	253,566
Derivative liabilities	35,773		39,839	87,948
FDIC indemnification liability	15,472		16,701	17,945
Accrued interest payable	9,177		6,421	8,007
Total financial liabilities	24,068,745		22,530,447	22,315,062
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	251,952		270,045	246,947
Interest bearing deposits with banks	1,218,728		980,457	816,104
Available-for-sale securities	1,665,903		1,724,667	1,650,096
Held-to-maturity securities	807,036		607,602	942,666
Trading account securities	643		1,989	1,092
FHLB and FRB stock, at cost	87,192		133,494	129,630
Brokerage customer receivables	23,631		25,181	25,511
Mortgage loans held-for-sale, at fair value	370,282		418,374	559,634
Loans held-for-investment, at fair value	29,704		22,137	17,603
Loans held-for-investment, at amortized cost	21,064,801		20,755,320	20,233,915
MSRs	29,414		19,103	13,901
Nonqualified deferred compensation assets	10,824		9,228	9,218
Derivative assets	48,198		56,394	88,828
Accrued interest receivable and other	225,435		204,513	205,725
Total financial assets	25,833,743		25,228,504	24,940,870
Non-maturity deposits	18,228,388		17,383,729	16,946,178
Deposits with stated maturities	4,608,760		4,263,576	4,200,278
FHLB advances	454,753		157,051	427,103
Other borrowings	251,680		262,486	241,366
Subordinated notes	145,376		135,268	138,715
Junior subordinated debentures	240,305		254,384	254,108
Derivative liabilities	35,773		39,839	87,948
FDIC indemnification liability	15,472		16,701	17,945
Accrued interest payable	9,177		6,421	8,007
Total financial liabilities	$ 23,989,684		$ 22,519,455	$ 22,321,648

Stock-Based Compensation Plan85

Stock-Based Compensation Plans (Weighted Average Assumptions Used To Determine The Options Fair Value) (Detail)	9 Months Ended
	Sep. 30, 2016
Share-based Compensation [Abstract]
Expected dividend yield	0.90%
Expected volatility	25.20%
Risk-free rate	1.30%
Expected option life (in years)	4 years 6 months

Stock-Based Compensation Plan86

Stock-Based Compensation Plans (Summary Of Stock Option Activity) (Detail) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Common Shares
Common Shares, Outstanding at beginning of the period (in shares)	1,698,912	1,551,734
Common Shares, Granted (in shares)	0	562,166
Common Shares, Exercised (in shares)	(499,222)	(184,366)
Common Shares, Forfeited or canceled (in shares)	(16,378)	(86,039)
Common Shares, Outstanding at end of the period (in shares)	1,183,312	1,843,495
Stock Options, Exercisable (in shares)	640,759	813,666
Weighted Average Strike Price
Weighted Average Strike Price, Outstanding at beginning of period (usd per share)	$ 41.50	$ 41.32
Weighted Average Strike Price, Granted (usd per share)	0	41.04
Weighted Average Strike Price, Exercised (usd per share)	40.57	37.43
Weighted Average Strike Price, Forfeited or canceled (usd per share)	43.07	48.93
Weighted Average Strike Price, Outstanding at end of period (usd per share)	41.87	41.27
Stock Options, Weighted Average Strike Price, Exercisable (usd per share)	$ 41.58	$ 39.27
Stock Options, Remaining Contractual Term, Outstanding, Years	4 years 2 months 12 days	4 years 9 months 18 days
Stock Options, Remaining Contractual Term, Exercisable, Years	3 years 6 months	3 years 6 months
Stock Options, Intrinsic Value, Outstanding	$ 43,122	$ 26,363
Stock Options, Intrinsic Value, Exercisable	$ 23,532	$ 13,265

Stock-Based Compensation Plan87

Stock-Based Compensation Plans (Summary Of Plans' Restricted Share And Performance-Vested Stock Award Activity) (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Restricted Stock
Common Shares
Shares, Beginning of the Period (in shares)	133,425	137,593
Shares, Granted (in shares)	14,249	15,764
Shares, Vested and issued (in shares)	(10,695)	(10,041)
Shares, Forfeited (in shares)	(2,551)	(598)
Shares, Outstanding, End of the Period (in shares)	134,428	142,718
Shares, Vested, but not issuable (in shares)	89,563	88,889
Weighted Average Grant-Date Fair Value
Weighted Average Grant-Date Fair Value (usd per share)	$ 49.94	$ 49.63
Weighted Average Grant-Date Fair Value, Granted (usd per share)	72.53	44.72
Weighted Average Grant-Date Fair Value, Vested and issued (usd per share)	46.03	43.78
Weighted Average Grant-Date Fair Value, Forfeited (usd per share)	52.26	44.26
Weighted Average Grant-Date Fair Value (usd per share)	52.60	49.52
Weighted Average Grant-Date Fair Value, Vested, but not issuable (usd per share)	$ 51.59	$ 51.44
Performance Shares
Common Shares
Shares, Beginning of the Period (in shares)	298,180	276,533
Shares, Granted (in shares)	145,829	118,072
Shares, Vested and issued (in shares)	(68,712)	(78,410)
Shares, Forfeited (in shares)	(14,164)	(13,229)
Shares, Outstanding, End of the Period (in shares)	361,133	302,966
Shares, Vested, but not issuable (in shares)	13,616	6,660
Weighted Average Grant-Date Fair Value
Weighted Average Grant-Date Fair Value (usd per share)	$ 43.64	$ 43.01
Weighted Average Grant-Date Fair Value, Granted (usd per share)	72.60	41.02
Weighted Average Grant-Date Fair Value, Vested and issued (usd per share)	46.85	37.90
Weighted Average Grant-Date Fair Value, Forfeited (usd per share)	52.81	41.12
Weighted Average Grant-Date Fair Value (usd per share)	54.36	43.64
Weighted Average Grant-Date Fair Value, Vested, but not issuable (usd per share)	$ 42.66	$ 37.93

Stock-Based Compensation Plan88

Stock-Based Compensation Plans (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	May 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants (in shares)	4,000,000		4,000,000
Number of stock options granted			0	562,166
Stock-based compensation expense	$ 2.4	$ 2	$ 8.2	$ 6.8
Weighted average grant date fair value per share of options granted (usd per share)				$ 8.61
Aggregate intrinsic value of options exercised			16.3	$ 2.7
Cash received from option exercises			$ 20.3	$ 6.9
2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares approved for issuance (in shares)					5,485,000
2007 Plan and 2015 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment award options term			7 years
2007 Plan and 2015 Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
2007 Plan and 2015 Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			5 years
1997 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment award options term			10 years
Restricted Stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			1 year
Restricted Stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			5 years
LTIP Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period			3 years
LTIP Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance based award payouts			0.00%
Granted after 2014 | LTIP Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance based award payouts			150.00%
Granted prior to 2015 | LTIP Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of performance based award payouts			200.00%

Shareholders' Equity And Earn89

Shareholders' Equity And Earnings Per Share (Components Of Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at the beginning			$ 2,695,617	$ 2,352,274
Other comprehensive income (loss) during the period, net of tax, before reclassifications	$ 5,087	$ 925	24,124	25,516
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	(16)	(1,359)	618	(2,094)
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax	(20)	2,295	(900)	6,707
Total other comprehensive income	5,051	1,861	23,842	30,129
Balance at the end	2,908,925	2,674,474	2,908,925	2,674,474
Accumulated Unrealized Gains (Losses) on Securities
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at the beginning	(15,022)	3,971	(29,309)	(17,674)
Other comprehensive income (loss) during the period, net of tax, before reclassifications	653	1,532	15,815	20,444
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	(24)	(2,005)	(19)	(3,684)
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax	(20)	2,295	(900)	6,707
Total other comprehensive income	609	1,822	14,896	23,467
Balance at the end	(14,413)	5,793	(14,413)	5,793
Accumulated Unrealized Losses on Derivative Instruments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at the beginning	4,959	(2,220)	4,165	(2,193)
Other comprehensive income (loss) during the period, net of tax, before reclassifications	228	1,037	393	66
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	8	646	637	1,590
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax	0	0	0	0
Total other comprehensive income	236	1,683	1,030	1,656
Balance at the end	5,195	(537)	5,195	(537)
Accumulated Foreign Currency Translation Adjustments
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at the beginning	(36,474)	(36,191)	(40,184)	(42,841)
Other comprehensive income (loss) during the period, net of tax, before reclassifications	4,206	(1,644)	7,916	5,006
Amount reclassified from accumulated other comprehensive income (loss) into net income, net of tax	0	0	0	0
Amount reclassified from accumulated other comprehensive income related to amortization of unrealized losses on investment securities transferred to held-to-maturity from available-for-sale, net of tax	0	0	0	0
Total other comprehensive income	4,206	(1,644)	7,916	5,006
Balance at the end	(32,268)	(37,835)	(32,268)	(37,835)
Accumulated other comprehensive loss
Activity Accumulated Other Comprehensive Income [Roll Forward]
Balance at the beginning	(46,537)	(34,440)	(65,328)	(62,708)
Total other comprehensive income			23,842	30,129
Balance at the end	$ (41,486)	$ (32,579)	$ (41,486)	$ (32,579)

Shareholders' Equity And Earn90

Shareholders' Equity And Earnings Per Share (Other Comprehensive Income Reclassified from AOCI) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Gains on investment securities, net	$ 39	$ 3,305	$ 31	$ 6,070
Income before taxes	104,248	85,054	294,212	243,522
Income tax expense	(38,622)	(31,939)	(105,311)	(91,255)
Interest on deposits	23,655	15,621	58,396	41,996
Interest on junior subordinated debentures	2,640	2,400	7,481	6,973
Net income	65,626	53,115	188,901	152,267
Reclassification Out of Accumulated Other Comprehensive Income | Accumulated Unrealized Gains (Losses) on Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Gains on investment securities, net	39	3,305	31	6,070
Income before taxes	39	3,305	31	6,070
Income tax expense	(15)	(1,300)	(12)	(2,386)
Net income	24	2,005	19	3,684
Reclassification Out of Accumulated Other Comprehensive Income | Accumulated Unrealized Losses on Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Income before taxes	(14)	(1,065)	(1,051)	(2,620)
Income tax expense	6	419	414	1,030
Interest on deposits	(380)	528	(15)	1,121
Interest on junior subordinated debentures	394	537	1,066	1,499
Net income	$ (8)	$ (646)	$ (637)	$ (1,590)

Shareholders' Equity And Earn91

Shareholders' Equity And Earnings Per Share (Computation Of Basic And Diluted Earnings Per Common Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract]
Net income	$ 65,626	$ 53,115	$ 188,901	$ 152,267
Less: Preferred stock dividends	2,050	3,628	7,728	10,884
Net income applicable to common shares	63,576	49,487	181,173	141,383
Add: Dividends on convertible preferred stock, if dilutive	0	1,578	1,578	4,735
Net income applicable to common shares—Diluted	$ 63,576	$ 51,065	$ 182,751	$ 146,118
Weighted average common shares outstanding (in shares)	55,796	51,679	54,292	49,763
Effect of dilutive potential common shares
Common stock equivalents (in shares)	966	938	988	822
Convertible preferred stock, if dilutive (in shares)	0	3,109	1,317	3,109
Total dilutive potential common shares (in shares)	966	4,047	2,305	3,931
Weighted average common shares and effect of dilutive potential common shares (in shares)	56,762	55,726	56,597	53,694
Net income per common share-Basic (usd per share)	$ 1.14	$ 0.96	$ 3.34	$ 2.84
Net income per common share-Diluted (usd per share)	$ 1.12	$ 0.92	$ 3.23	$ 2.72

Shareholders' Equity And Earn92

Shareholders' Equity And Earnings Per Share (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Thousands	Apr. 27, 2017	Apr. 25, 2017	Dec. 19, 2008	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2012	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Temporary Equity [Line Items]
Stock issued in public offering, shares				3,000,000
Proceeds from the issuance of common stock, net				$ 152,900							$ 0	$ 152,823
Cash dividends declared per common share (usd per share)							$ 0.14	$ 0.14	$ 0.14	$ 0.12	$ 0.42	$ 0.36
Common stock dividends per share declared annualized (usd per share)							$ 0.56	$ 0.56	$ 0.56
US Treasury
Temporary Equity [Line Items]
Warrants outstanding, shares			1,643,295				46,859				46,859
Warrant termination period			10 years
Investment warrants, exercise price (usd per share)											$ 22.66
Warrants exercised, shares											294,993
Common stock shares issued from exercise of warrants											202,325
Common stock
Temporary Equity [Line Items]
Common stock issued, conversion of preferred stock, shares	3,069,828	51,244											729
Series D Preferred Stock
Temporary Equity [Line Items]
Preferred stock, shares issued (in shares)					5,000,000		5,000,000			5,000,000	5,000,000	5,000,000	5,000,000
Preferred stock, liquidation value per share (usd per share)					$ 25		$ 25			$ 25	$ 25	$ 25	$ 25
Preferred stock, value					$ 125,000		$ 125,000			$ 125,000	$ 125,000	$ 125,000	$ 125,000
Preferred stock, dividend rate, percentage					6.50%
Series C Preferred Stock
Temporary Equity [Line Items]
Preferred stock, shares issued (in shares)						126,500
Preferred stock, liquidation value per share (usd per share)						$ 1,000	$ 1,000			$ 1,000	$ 1,000	$ 1,000	$ 1,000
Preferred stock, value						$ 126,500	$ 0			$ 126,257	$ 0	$ 126,257	$ 126,257
Preferred stock, dividend rate, percentage						5.00%
Convertible preferred stock, rate of conversion, shares	24.72
Number of shares converted	124,184	2,073											30
London Interbank Offered Rate (LIBOR) | Series D Preferred Stock
Temporary Equity [Line Items]
Preferred stock, dividend rate, percentage, variable spread					4.06%

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	Oct. 16, 2017	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Line Items]
Payments for FDIC loss share agreements			$ 1,049	$ (1,704)	$ 258	$ (2,124)
Forecast
Subsequent Event [Line Items]
Gain contract termination		$ 400
Subsequent Event
Subsequent Event [Line Items]
Payments for FDIC loss share agreements	$ 15,200