First Midwest Bancorp (ONBPP) 10-Q 6 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	FIRST MIDWEST BANCORP INC
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		106,382,834
Amendment Flag	false
Entity Central Index Key	702,325
Entity Filer Category	Large Accelerated Filer
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Entity Small Business	false
Entity Emerging Growth Company	false

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 185,239	$ 192,800
Interest-bearing deposits in other banks	111,360	153,770
Trading securities, at fair value	0	20,447	[1]
Equity securities, at fair value	29,046	0
Securities available-for-sale, at fair value	2,179,410
Securities available-for-sale, at fair value		1,884,209
Securities held-to-maturity, at amortized cost	12,673	13,760
Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock, at cost	87,728	69,708
Loans	11,050,548	10,437,812
Allowance for loan losses	(99,925)	(95,729)
Net loans	10,950,623	10,342,083
Other real estate owned (OREO)	12,244	20,851
Premises, furniture, and equipment, net	126,389	123,316
Investment in bank-owned life insurance (BOLI)	284,074	279,900
Goodwill and other intangible assets	751,248	754,757
Accrued interest receivable and other assets	231,465	221,451
Total assets	14,961,499	14,077,052
Liabilities
Noninterest-bearing deposits	3,618,384	3,576,190
Interest-bearing deposits	7,908,730	7,477,135
Total deposits	11,527,114	11,053,325
Borrowed funds	1,073,546	714,884
Senior and subordinated debt	195,595	195,170
Accrued interest payable and other liabilities	247,569	248,799
Total liabilities	13,043,824	12,212,178
Stockholders' Equity
Common stock	1,124	1,123
Additional paid-in capital	1,028,635	1,031,870
Retained earnings	1,164,133	1,074,990
Accumulated other comprehensive loss, net of tax	(75,133)	(33,036)
Treasury stock, at cost	(201,084)	(210,073)
Total stockholders' equity	1,917,675	1,864,874
Total liabilities and stockholders' equity	$ 14,961,499	$ 14,077,052
Stockholders' Equity, Number of Shares, Par Value, and Other Disclosures
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	112,359,000	112,351,000
Common stock, shares outstanding (in shares)	103,058,000	102,717,000
Treasury stock, shares (in shares)	9,301,000	9,634,000
[1]	As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest Income
Loans	$ 133,997	$ 118,101	$ 380,420	$ 345,286
Investment securities	14,170	10,667	38,936	31,678
Other short-term investments	1,365	1,148	3,609	3,167
Total interest income	149,532	129,916	422,965	380,131
Interest Expense
Deposits	10,426	4,369	24,637	11,307
Borrowed funds	3,927	2,544	10,919	6,837
Senior and subordinated debt	3,152	3,110	9,416	9,314
Total interest expense	17,505	10,023	44,972	27,458
Net interest income	132,027	119,893	377,993	352,673
Provision for loan losses	11,248	10,109	38,043	23,266
Net interest income after provision for loan losses	120,779	109,784	339,950	329,407
Noninterest Income
Service charges on deposit accounts	12,378	12,561	36,088	36,079
Wealth management fees	10,622	10,169	32,561	30,354
Card-based fees, net	4,123	5,992	12,450	22,940
Capital market products income	1,936	2,592	6,313	6,185
Mortgage banking income	1,657	2,246	5,790	5,779
Other service charges, commissions, and fees	2,786	4,745	8,172	16,043
Net securities gains	0		0
Net securities gains		3,197		3,481
Other income	2,164	1,846	6,756	7,383
Total noninterest income	35,666	43,348	108,130	128,244
Noninterest Expense
Salaries and employee benefits	54,160	55,638	168,879	165,985
Net occupancy and equipment expense	13,183	12,115	40,607	36,925
Professional services	7,944	8,498	23,822	26,073
Technology and related costs	4,763	4,505	14,371	13,423
Net OREO expense	(413)	657	399	3,988
Other expenses	14,541	15,393	40,083	47,066
Delivering Excellence implementation costs	2,239	0	17,254	0
Acquisition and integration related expenses	60	384	60	20,123
Total noninterest expense	96,477	97,190	305,475	313,583
Income before income tax expense	59,968	55,942	142,605	144,068
Income tax expense	6,616	17,707	26,143	48,028
Net income	$ 53,352	$ 38,235	$ 116,462	$ 96,040
Per Common Share Data
Basic earnings per common share (in dollars per share)	$ 0.52	$ 0.37	$ 1.13	$ 0.94
Diluted earnings per common share (in dollars per share)	0.52	0.37	1.13	0.94
Dividends declared per common share (in dollars per share)	$ 0.11	$ 0.10	$ 0.33	$ 0.29
Weighted-average common shares outstanding (in Shares)	102,178	101,752	102,087	101,307
Weighted-average diluted common shares outstanding (in Shares)	102,178	101,772	102,092	101,327

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 53,352	$ 38,235	$ 116,462	$ 96,040
Unrealized holding (losses) gains:
Before tax	(13,632)	428	(47,765)	11,078
Tax effect	3,548	(174)	13,055	(4,436)
Net of tax	(10,084)	254	(34,710)	6,642
Reclassification of net gains included in net income:
Before tax	0	3,197	0	3,481
Tax effect	0	(1,311)	0	(1,425)
Net of tax	0	1,886	0	2,056
Net unrealized holding (losses) gains	(10,084)	(1,632)	(34,710)	4,586
Derivative Instruments
Before tax	(880)	276	(948)	(2,849)
Tax effect	231	(113)	250	1,137
Net of tax	(649)	163	(698)	(1,712)
Total other comprehensive (loss) income	(10,733)	(1,469)	(35,408)	2,874
Total comprehensive income	$ 42,619	$ 36,766	$ 81,054	$ 98,914

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income - AOCI - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		$ 1,864,874	$ 1,257,080
Other comprehensive income (loss)		(35,408)	2,874
Adjustments to apply recent accounting pronouncements	[1]			$ 0
Ending balance		1,917,675	1,865,130
Accumulated Unrealized Loss on Securities Available- for-Sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(13,976)	(22,645)
Other comprehensive income (loss)		(34,710)	4,586
Adjustments to apply recent accounting pronouncements	[2]			(2,864)
Ending balance		(51,550)	(18,059)
Accumulated Unrealized Loss on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(3,763)	(1,176)
Other comprehensive income (loss)		(698)	(1,712)
Adjustments to apply recent accounting pronouncements	[2]			(784)
Ending balance		(5,245)	(2,888)
Unrecognized Net Pension Costs
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(15,297)	(17,089)
Other comprehensive income (loss)		0	0
Adjustments to apply recent accounting pronouncements	[2]			(3,041)
Ending balance		(18,338)	(17,089)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(33,036)	(40,910)
Other comprehensive income (loss)		(35,408)	2,874
Adjustments to apply recent accounting pronouncements	[1],[2]			$ (6,689)
Ending balance		$ (75,133)	$ (38,036)
[1]	As a result of accounting guidance adopted in the first quarter of 2018, certain reclassifications were made from accumulated other comprehensive loss to retained earnings as of January 1, 2018. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."
[2]	As a result of accounting guidance adopted in the first quarter of 2018, certain reclassifications were made from accumulated other comprehensive loss to retained earnings as of January 1, 2018. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."

Consolidated Statements of Chan

Consolidated Statements of Changes In Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss		Treasury Stock
Beginning balance (in shares) at Dec. 31, 2016			81,325,000
Beginning balance at Dec. 31, 2016		$ 1,257,080	$ 913	$ 498,937	$ 1,016,674	$ (40,910)		$ (218,534)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		96,040			96,040
Other comprehensive income		2,874				2,874
Common dividends declared ($0.29 and $0.33 per common share in 2017 and 2018, respectively)		(29,793)			(29,793)
Acquisitions, net of issuance costs (in shares)			21,078,000
Acquisitions, net of issuance costs		534,090	$ 210	533,322				558
Common stock issued (in shares)			7,000
Common stock issued		175		175
Restricted stock activity (in shares)			321,000
Restricted stock activity		(3,679)		(11,987)				8,308
Treasury stock issued to benefit plans (in shares)			(9,000)
Treasury stock issued to benefit plans		(211)		1				(212)
Share-based compensation expense		8,554		8,554
Ending balance (in shares) at Sep. 30, 2017			102,722,000
Ending balance at Sep. 30, 2017		1,865,130	$ 1,123	1,029,002	1,082,921	(38,036)		(209,880)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to apply recent accounting pronouncements	[1]	$ 0			6,689	(6,689)	[2]
Beginning balance (in shares) at Dec. 31, 2017		102,717,000	102,717,000
Beginning balance at Dec. 31, 2017		$ 1,864,874	$ 1,123	1,031,870	1,074,990	(33,036)		(210,073)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		116,462			116,462
Other comprehensive income		(35,408)				(35,408)
Common dividends declared ($0.29 and $0.33 per common share in 2017 and 2018, respectively)		(34,008)			(34,008)
Acquisitions, net of issuance costs		0
Common stock issued (in shares)			8,000
Common stock issued		895	$ 1	227				667
Restricted stock activity (in shares)			335,000
Restricted stock activity		(4,241)		(12,667)				8,426
Treasury stock issued to benefit plans (in shares)			(2,000)
Treasury stock issued to benefit plans		(63)		41				(104)
Share-based compensation expense		$ 9,164		9,164
Ending balance (in shares) at Sep. 30, 2018		103,058,000	103,058,000
Ending balance at Sep. 30, 2018		$ 1,917,675	$ 1,124	$ 1,028,635	$ 1,164,133	$ (75,133)		$ (201,084)
[1]	As a result of accounting guidance adopted in the first quarter of 2018, certain reclassifications were made from accumulated other comprehensive loss to retained earnings as of January 1, 2018. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."
[2]	As a result of accounting guidance adopted in the first quarter of 2018, certain reclassifications were made from accumulated other comprehensive loss to retained earnings as of January 1, 2018. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."

Consolidated Statements of Ch_2

Consolidated Statements of Changes In Stockholders' Equity (Parentheticals) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Dividends declared per common share (in dollars per share)	$ 0.11	$ 0.10	$ 0.33	$ 0.29

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating Activities
Net income	$ 116,462	$ 96,040
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	38,043	23,266
Depreciation of premises, furniture, and equipment	11,693	10,477
Net amortization of premium on securities	11,444	12,334
Net securities gains	0
Net securities gains		(3,481)
Gains on sales of 1-4 family mortgages and corporate loans held-for-sale	(4,475)	(5,354)
Net (gains) losses on sales and valuation adjustments of OREO	(318)	944
Amortization of the FDIC indemnification asset	906	906
Net losses (gains) on sales and valuation adjustments of premises, furniture, and equipment	5,423	(364)
BOLI income	(4,280)	(4,095)
Share-based compensation expense	9,164	8,554
Tax benefit related to share-based compensation	208	252
Amortization of other intangible assets	5,368	6,059
Originations of mortgage loans held-for-sale	(175,408)	(183,907)
Proceeds from sales of mortgage loans held-for-sale	193,476	190,544
Net increase in equity securities	(1,191)	0
Net increase in trading securities	0	(2,505)
Net increase in accrued interest receivable and other assets	(14,725)	(191,492)
Net decrease in accrued interest payables and other liabilities	(1,949)	(8,463)
Net cash provided by (used in) operating activities	189,841	(50,285)
Investing Activities
Proceeds from maturities, repayments, and calls of securities available-for-sale	233,659	251,160
Proceeds from sales of securities available-for-sale	0	437,401
Purchases of securities available-for-sale	(595,477)	(289,244)
Proceeds from maturities, repayments, and calls of securities held-to-maturity	1,087	7,663
Purchases of securities held-to-maturity	0	(10)
Net purchases of FHLB stock	(18,020)	(7,330)
Net increase in loans	(649,197)	(392,384)
Premiums paid on BOLI, net of proceeds from claims	106	132
Proceeds from sales of OREO	12,951	17,460
Proceeds from sales of premises, furniture, and equipment	549	13,135
Purchases of premises, furniture, and equipment	(20,738)	(11,680)
Net cash received from acquisitions	0	41,717
Net cash (used in) provided by investing activities	(1,035,080)	68,020
Financing Activities
Net increase in deposit accounts	473,789	356,020
Net increase (decrease) in borrowed funds	358,662	(178,472)
Cash dividends paid	(32,942)	(26,852)
Restricted stock activity	(4,241)	(3,679)
Net cash provided by financing activities	795,268	147,017
Net (decrease) increase in cash and cash equivalents	(49,971)	164,752
Cash and cash equivalents at beginning of period	346,570	262,148
Cash and cash equivalents at end of period	296,599	426,900
Supplemental Disclosures of Cash Flow Information:
Income taxes (refunded) paid	(7,001)	14,310
Interest paid to depositors and creditors	43,270	27,538
Dividends declared, but unpaid	11,250	10,184
Stock issued for acquisitions, net of issuance costs	0	534,090
Non-cash transfers of loans to OREO	4,026	3,770
Non-cash transfers of loans held-for-investment to loans held-for-sale	12,373	42,970
Non-cash transfer of trading securities and securities available-for-sale to equity securities	$ 27,855	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation – The accompanying unaudited condensed consolidated interim financial statements ("consolidated financial statements") of First Midwest Bancorp, Inc. (the " Company "), a Delaware corporation, were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (" SEC ") for quarterly reports on Form 10-Q and reflect all adjustments that management deems necessary for the fair presentation of the financial position and results of operations for the periods presented. The results of operations for the quarter and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . The accounting and reporting policies of the Company and its subsidiaries conform to U.S. generally accepted accounting principles (" GAAP ") and general practices within the banking industry. The accompanying consolidated financial statements do not include certain information and note disclosures required by GAAP for complete annual financial statements. Therefore, these financial statements should be read in conjunction with the Company 's 2017 Annual Report on Form 10-K (" 2017 10-K"). The Company uses the accrual basis of accounting for financial reporting purposes. Certain reclassifications were made to prior year amounts to conform to the current year presentation. Use of Estimates – The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates and assumptions are based on the best available information, actual results could differ from those estimates. Principles of Consolidation – The accompanying consolidated financial statements include the financial position and results of operations of the Company and its subsidiaries after elimination of all significant intercompany accounts and transactions. Assets held in a fiduciary or agency capacity are not assets of the Company or its subsidiaries and are not included in the consolidated financial statements. The accounting policies related to business combinations, loans, the allowance for credit losses, and derivative financial instruments are presented below. For a summary of all other significant accounting policies, see Note 1, "Summary of Significant Accounting Policies," in the Company 's 2017 10-K. Business Combinations – Business combinations are accounted for under the acquisition method of accounting. Assets acquired and liabilities assumed are recorded at their estimated fair values as of the date of acquisition, with any excess of the purchase price of the acquisition over the fair value of the identifiable net tangible and intangible assets acquired recorded as goodwill. Alternatively, a gain is recorded if the fair value of assets purchased exceeds the fair value of liabilities assumed and consideration paid. The results of operations of the acquired business are included in the Condensed Consolidated Statements of Income from the effective date of the acquisition. Loans – Loans held-for-investment are loans that the Company intends to hold until they are paid in full and are carried at the principal amount outstanding, including certain net deferred loan origination fees. Loan origination fees, commitment fees, and certain direct loan origination costs are deferred, and the net amount is amortized as a yield adjustment over the contractual life of the related loans or commitments and included in interest income. Fees related to letters of credit are amortized into fee income over the contractual life of the commitment. Other credit-related fees are recognized as fee income when earned. The Company 's net investment in direct financing leases is included in loans and consists of future minimum lease payments and estimated residual values, net of unearned income. Interest income on loans is accrued based on principal amounts outstanding. Loans held-for-sale are carried at the lower of aggregate cost or fair value and included in other assets in the Consolidated Statements of Financial Condition. Acquired and Covered Loans – Covered loans consists of loans acquired by the Company in Federal Deposit Insurance Corporation (" FDIC ")-assisted transactions, which are covered by loss share agreements with the FDIC (the " FDIC Agreements "), under which the FDIC reimburses the Company for the majority of the losses and eligible expenses related to these assets during the coverage period. Acquired loans consist of all other loans that were acquired in business combinations that are not covered by the FDIC Agreements. Certain loans that were previously classified as covered loans are no longer covered under the FDIC Agreements, and are included in acquired loans. Covered loans and acquired loans are included within loans held-for-investment. Acquired and covered loans are separated into (i) non-purchased credit impaired (" non-PCI ") and (ii) purchased credit impaired (" PCI ") loans. Non-PCI loans include loans that did not have evidence of credit deterioration since origination at the acquisition date. PCI loans include loans that had evidence of credit deterioration since origination and for which it was probable at acquisition that the Company would not collect all contractually required principal and interest payments. Evidence of credit deterioration was evaluated using various indicators, such as past due and non-accrual status. Leases and revolving loans do not qualify to be accounted for as PCI loans and are accounted for as non-PCI loans. The acquisition adjustment related to non-PCI loans is amortized into interest income over the contractual life of the related loans. If an acquired non-PCI loan is renewed subsequent to the acquisition date, any remaining acquisition adjustment is accreted into interest income and the loan is considered a new loan that is no longer classified as an acquired loan. PCI loans are accounted for based on estimates of expected future cash flows. To estimate the fair value, the Company generally aggregates purchased consumer loans and commercial loans into pools of loans with common risk characteristics, such as delinquency status, credit score, and internal risk ratings. The fair values of larger balance commercial loans are estimated on an individual basis. Expected future cash flows in excess of the fair value of loans at the purchase date ("accretable yield") are recorded as interest income over the life of the loans if the timing and amount of the expected future cash flows can be reasonably estimated. The non-accretable yield represents the difference between contractually required payments and the expected future cash flows determined at acquisition. Subsequent increases in expected future cash flows are offset against the allowance for credit losses to the extent an allowance has been established or otherwise recognized as interest income prospectively. The present value of any decreases in expected future cash flows is recognized by recording a charge-off through the allowance for loan losses or providing an allowance for loan losses. 90-Days Past Due Loans – The Company 's accrual of interest on loans is generally discontinued at the time the loan is 90 days past due unless the credit is sufficiently collateralized and in the process of renewal or collection. Non-accrual Loans – Generally, corporate loans are placed on non-accrual status (i) when either principal or interest payments become 90 days or more past due unless the credit is sufficiently collateralized and in the process of renewal or collection, or (ii) when an individual analysis of a borrower's creditworthiness warrants a downgrade to non-accrual regardless of past due status. When a loan is placed on non-accrual status, unpaid interest credited to income in the current year is reversed, and unpaid interest accrued in prior years is charged against the allowance for loan losses. After the loan is placed on non-accrual status, all debt service payments are applied to the principal on the loan. Future interest income may only be recorded on a cash basis after recovery of principal is reasonably assured. Non-accrual loans are returned to accrual status when the financial position of the borrower and other relevant factors indicate that the Company will collect all principal and interest. Commercial loans and loans secured by real estate are charged-off when deemed uncollectible. A loss is recorded if the net realizable value of the underlying collateral is less than the outstanding principal and interest. Consumer loans that are not secured by real estate are subject to mandatory charge-off at a specified delinquency date and are usually not classified as non-accrual prior to being charged-off. Closed-end consumer loans, which include installment, automobile, and single payment loans, are usually charged-off no later than the end of the month in which the loan becomes 120 days past due. PCI loans are generally considered accruing loans unless reasonable estimates of the timing and amount of expected future cash flows cannot be determined. Loans without reasonable future cash flow estimates are classified as non-accrual loans, and interest income is not recognized on those loans until the timing and amount of the expected future cash flows can be reasonably determined. Troubled Debt Restructurings ( " TDR s" ) – A restructuring is considered a TDR when (i) the borrower is experiencing financial difficulties, and (ii) the creditor grants a concession, such as forgiveness of principal, reduction of the interest rate, changes in payments, or extension of the maturity date. Loans are not classified as TDR s when the modification is short-term or results in an insignificant delay in payments. The Company 's TDR s are determined on a case-by-case basis. The Company does not accrue interest on a TDR unless it believes collection of all principal and interest under the modified terms is reasonably assured. For a TDR to begin accruing interest, the borrower must demonstrate some level of past performance and the future capacity to perform under the modified terms. Generally, six months of consecutive payment performance under the restructured terms is required before a TDR is returned to accrual status. However, the period could vary depending on the individual facts and circumstances of the loan. An evaluation of the borrower's current creditworthiness is used to assess the borrower's capacity to repay the loan under the modified terms. This evaluation includes an estimate of expected future cash flows, evidence of strong financial position, and estimates of the value of collateral, if applicable. For TDR s to be removed from TDR status in the calendar year after the restructuring, the loans must (i) have an interest rate and terms that reflect market conditions at the time of restructuring, and (ii) be in compliance with the modified terms. If the loan was restructured at below market rates and terms, it continues to be separately reported as restructured until it is paid in full or charged-off. Impaired Loans – Impaired loans consist of corporate non-accrual loans and TDR s. A loan is considered impaired when it is probable that the Company will not collect all contractual principal and interest. With the exception of accruing TDR s, impaired loans are classified as non-accrual and are exclusive of smaller homogeneous loans, such as home equity, 1-4 family mortgages, and installment loans. Impaired loans with balances under a specified threshold are not individually evaluated for impairment. For all other impaired loans, impairment is measured by comparing the estimated value of the loan to the recorded book value. The value of collateral-dependent loans is based on the fair value of the underlying collateral, less costs to sell. The value of other loans is measured using the present value of expected future cash flows discounted at the loan's initial effective interest rate. Allowance for Credit Losses – The allowance for credit losses is comprised of the allowance for loan losses and the reserve for unfunded commitments, and is maintained by management at a level believed adequate to absorb estimated losses inherent in the existing loan portfolio. Determination of the allowance for credit losses is subjective since it requires significant estimates and management judgment, including the amounts and timing of expected future cash flows on impaired loans, estimated losses on pools of homogeneous loans, consideration of current economic trends, and other factors. Loans deemed to be uncollectible are charged-off against the allowance for loan losses, while recoveries of amounts previously charged-off are credited to the allowance for loan losses. Additions to the allowance for loan losses are charged to expense through the provision for loan losses. The amount of provision depends on a number of factors, including net charge-off levels, loan growth, changes in the composition of the loan portfolio, and the Company 's assessment of the allowance for loan losses based on the methodology discussed below. Allowance for Loan Losses – The allowance for loan losses consists of (i) specific reserves for individual loans where the recorded investment exceeds the value, (ii) an allowance based on a loss migration analysis that uses historical credit loss experience for each loan category, and (iii) an allowance based on other internal and external qualitative factors. The specific reserves component of the allowance for loan losses is based on a periodic analysis of impaired loans exceeding a fixed dollar amount. If the value of an impaired loan is less than the recorded book value, the Company either establishes a valuation allowance (i.e., a specific reserve) equal to the excess of the book value over the collateral value of the loan as a component of the allowance for loan losses or charges off the amount if it is a confirmed loss. The general reserve component is based on a loss migration analysis, which examines actual loss experience by loan category for a rolling 8-quarter period and the related internal risk rating for corporate loans. The loss migration analysis is updated quarterly, primarily using actual loss experience. This component is then adjusted based on management's consideration of many internal and external qualitative factors, including: • Changes in the composition of the loan portfolio, trends in the volume of loans, and trends in delinquent and non-accrual loans that could indicate that historical trends do not reflect current conditions. • Changes in credit policies and procedures, such as underwriting standards and collection, charge-off, and recovery practices. • Changes in the experience, ability, and depth of credit management and other relevant staff. • Changes in the quality of the Company 's loan review system and Board of Directors oversight. • The effect of any concentration of credit and changes in the level of concentrations, such as loan type or risk rating. • Changes in the value of the underlying collateral for collateral-dependent loans. • Changes in the national and local economy that affect the collectability of various segments of the portfolio. • The effect of other external factors, such as competition and legal and regulatory requirements, on the Company 's loan portfolio. The allowance for loan losses also consists of an allowance on acquired and covered non-PCI and PCI loans. No allowance for loan losses is recorded on acquired loans at the acquisition date. Subsequent to the acquisition date, an allowance for credit losses is established as necessary to reflect credit deterioration. The acquired non-PCI allowance is based on management's evaluation of the acquired non-PCI loan portfolio giving consideration to the current portfolio balance, including the remaining acquisition adjustments, maturity dates, and overall credit quality. The allowance for covered non-PCI loans is calculated in the same manner as the general reserve component based on a loss migration analysis as discussed above. The acquired and covered PCI allowance reflects the difference between the carrying value and the discounted expected future cash flows of the acquired and covered PCI loans. On a periodic basis, the adequacy of this allowance is determined through a re-estimation of expected future cash flows on all of the outstanding acquired and covered PCI loans using either a probability of default/loss given default (" PD/LGD ") methodology or a specific review methodology. The PD/LGD model is a loss model that estimates expected future cash flows using a probability of default curve and loss given default estimates. Acquired non-PCI loans that have renewed subsequent to the respective acquisition dates are no longer classified as acquired loans. Instead, they are included in the general loan population and allocated an allowance based on a loss migration analysis. Reserve for Unfunded Commitments – The Company also maintains a reserve for unfunded commitments, including letters of credit, for the risk of loss inherent in these arrangements. The reserve for unfunded commitments is estimated using the loss migration analysis from the allowance for loan losses, adjusted for probabilities of future funding requirements. The reserve for unfunded commitments is included in other liabilities in the Consolidated Statements of Financial Condition. The establishment of the allowance for credit losses involves a high degree of judgment given the difficulty of assessing the factors impacting loan repayment and estimating the timing and amount of losses. While management utilizes its best judgment and information available, the adequacy of the allowance for credit losses depends on a variety of factors beyond the Company 's control, including the performance of its loan portfolio, the economy, changes in interest rates and property values, and the interpretation of loan risk classifications by regulatory authorities. Derivative Financial Instruments – To provide derivative products to customers and in the ordinary course of business, the Company enters into derivative transactions as part of its overall interest rate risk management strategy to minimize significant unplanned fluctuations in earnings and expected future cash flows caused by interest rate volatility. All derivative instruments are recorded at fair value as either other assets or other liabilities in the Consolidated Statements of Financial Condition. Subsequent changes in a derivative's fair value are recognized in earnings unless specific hedge accounting criteria are met. On the date the Company enters into a derivative contract, the derivative is designated as a fair value hedge, a cash flow hedge, or a non-hedge derivative instrument. Fair value hedges are designed to mitigate exposure to changes in the fair value of an asset or liability attributable to a particular risk, such as interest rate risk. Cash flow hedges are designed to mitigate exposure to variability in expected future cash flows to be received or paid related to an asset, liability, or other type of forecasted transaction. The Company formally documents all relationships between hedging instruments and hedged items, including its risk management objective and strategy at inception. At the hedge's inception, a formal assessment is performed to determine the effectiveness of the derivative in offsetting changes in the fair values or expected future cash flows of the hedged items in the current period and prospectively. If a derivative instrument designated as a hedge is terminated or ceases to be highly effective, hedge accounting is discontinued prospectively, and the gain or loss is amortized into earnings. For fair value hedges, the gain or loss is amortized over the remaining life of the hedged asset or liability. For cash flow hedges, the gain or loss is amortized over the same period that the forecasted hedged transactions impact earnings. If the hedged item is disposed of, any fair value adjustments are included in the gain or loss from the disposition of the hedged item. If the forecasted transaction is no longer probable, the gain or loss is included in earnings immediately. For fair value hedges, changes in the fair value of the derivative instruments, as well as changes in the fair value of the hedged item, are recognized in earnings in the same income statement line item as the earnings effect of the hedged item. For cash flow hedges, the effective portion of the change in fair value of the derivative instrument is reported as a component of accumulated other comprehensive loss and is reclassified to earnings when the hedged transaction is reflected in earnings.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS Adopted Accounting Pronouncements Revenue from Contracts with Customers: In May of 2014, the Financial Accounting Standards Board ("FASB") issued guidance that requires an entity to 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. In March of 2016, the FASB issued an amendment to this guidance to clarify the implementation of guidance on principal versus agent consideration. Additional amendments to clarify the implementation guidance on the identification of performance obligations and licensing were issued in April of 2016 and narrow-scope improvements and practical expedients were issued in May of 2016. The guidance is effective for annual and interim reporting periods beginning on or after December 15, 2017, and must be applied either retrospectively or using the modified retrospective approach. The Company's revenue is comprised of net interest income on financial assets and liabilities, which is excluded from the scope of this guidance, and noninterest income. The primary sources of revenue within noninterest income are service charges on deposit accounts, wealth management fees, card-based fees, and merchant servicing fees. The adoption of this guidance on January 1, 2018, using the modified retrospective approach, affected how the Company presents merchant servicing fees, merchant card expenses, card-based fees, and cardholder expenses, which are presented on a gross basis within noninterest income and noninterest expense for the prior period and are presented on a net basis within noninterest income for the current period. Total expenses of $4.2 million and $11.9 million for the quarter and nine months ended September 30, 2018 were netted in noninterest income. The adoption of this guidance did not impact net income; therefore, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Consistent with the modified retrospective approach, the Company did not adjust prior period amounts for the reclassification of merchant card expenses and cardholder expenses. A description of the Company's revenue streams accounted for under the scope of this guidance follows: Service charges on deposit accounts – Service charges on deposit accounts consist of account analysis fees (net fees earned on analyzed business and public checking accounts), monthly service fees, and other deposit account related fees. The Company's performance obligation for account analysis fees and monthly service fees is generally satisfied, and the related revenue recognized, over the period in which the service is provided. Other deposit account related fees are largely transactional based and, therefore, the Company's performance obligation is satisfied, and related revenue recognized, at a point in time. Payment for service charges on deposit accounts is primarily received as a direct charge to customers' accounts. As a result of the adoption of this guidance, there was no impact to the method of recognizing revenue related to service charges on deposit accounts for the quarter and nine months ended September 30, 2018 . Wealth management fees – Wealth management fees represents quarterly fees due from wealth management customers as consideration for managing the customers' assets. Wealth management services include custody of assets, investment management, escrow services, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed each quarter, which is generally the time that payment is received. Also included are fees received from a third-party broker-dealer as part of a revenue-sharing agreement. These fees are paid to us by the third-party on a quarterly basis and recognized ratably throughout the quarter as our performance obligation is satisfied. As a result of the adoption of this guidance, there was no impact to the method of recognizing revenue related to wealth management fees for the quarter and nine months ended September 30, 2018 . Card-based fees, net – Card-based fees, net consists of debit and credit card interchange fees for processing transactions, as well as various fees for automated teller machine ("ATM") and point-of-sale transactions processed through the related networks. Interchange, ATM, and point-of-sale fees from cardholder transactions represent a percentage of the underlying transaction value or a flat fee and are recognized daily in connection with the transaction processing services provided to the cardholder. Card-based fees are presented net of certain contract costs associated with the debit, credit and ATM card interchange networks. As a result of the adoption of this guidance, $1.9 million and $5.5 million of cardholder expenses are netted against card-based fees for the quarter and nine months ended September 30, 2018 , respectively. Merchant servicing fees, net – Merchant servicing fees, net is included in other service charges, commissions, and fees in the Consolidated Statements of Income. The Company acts in an agency capacity with respect to its merchants to process their debit and credit card transactions, deriving revenue from assisting another entity in transactions with the Company's customers. Merchant servicing fees represent a percentage of the underlying net transaction volume or a flat fee and are recognized monthly. Merchant servicing fees are presented net of certain contract costs associated with the third-party merchant processing. As a result of the adoption of this guidance, $2.3 million and $6.4 million of merchant card expenses are netted against merchant servicing fees for the quarter and nine months ended September 30, 2018 , respectively. Amendments to Guidance on Classifying and Measuring Financial Instruments: In January of 2016, the FASB issued guidance that will require entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value. Any subsequent changes in fair value will be recognized in net income unless the investments qualify for a new practicability exception. Equity securities totaling $29.0 million are no longer classified as trading securities or securities available-for-sale. This guidance also requires entities to adjust the fair value disclosures for financial instruments carried at amortized cost from an entry price to an exit price. No changes were made to the guidance for classifying and measuring investments in debt securities and loans. Except as discussed above, the adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Classification of Certain Cash Receipts and Cash Payments: In August of 2016, the FASB issued guidance clarifying certain cash flow presentation and classification issues to reduce diversity in practice. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Income Taxes: In October of 2016, the FASB issued guidance that requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Clarifying the Definition of a Business: In January of 2017, the FASB issued guidance that clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. The adoption of this guidance on January 1, 2018 did not impact the Company's financial condition, results of operations, or liquidity. Presentation of Defined Benefit Retirement Plan Costs: In March of 2017, the FASB issued guidance that changes how employers that sponsor defined pension and or other postretirement benefit plans present the net periodic benefit cost in the income statement. Employers are required to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. Other components of net periodic benefit cost are required to be presented separately from the line item(s) that includes the service cost. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Share-based Payment Award Modifications: In May of 2017, the FASB issued guidance to reduce diversity in practice by clarifying when changes to the terms or conditions of a share-based payment award must be accounted for as a modification. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Derivatives and Hedging: In August of 2017, the FASB issued guidance to better align the financial reporting related to hedging activities with the economic objectives of those activities and to simplify the application of current hedge accounting guidance. Entities are required to apply the guidance using a modified retrospective method as of the period of adoption. This guidance is effective for annual and interim periods beginning after December 31, 2018. Early adoption is permitted, and the Company elected to do so on January 1, 2018, which did not materially impact the Company's financial condition, results of operations, or liquidity. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income: In February of 2018, the FASB issued guidance that requires a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 . Entities electing the reclassification are required to apply the guidance either at the beginning of the period of adoption or retrospectively for all periods impacted. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted and the Company elected to do so on January 1, 2018, which resulted in the reclassification of $6.8 million of stranded tax effects from accumulated other comprehensive loss to retained earnings as of the beginning of the period of adoption. Accounting Pronouncements Pending Adoption Leases: In February of 2016, the FASB issued guidance to increase transparency and comparability across entities for leasing arrangements. This guidance requires lessees to recognize assets and liabilities for most leases. For lessors, this guidance modifies the lease classification criteria and the accounting for sales-type and direct financing leases. In addition, this guidance clarifies criteria for the determination of whether a contract is or contains a lease. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company will adopt this guidance on January 1, 2019, which will result in the recognition of right-of-use assets and associated lease liabilities for its operating leases. The amount of right-of-use assets and associated lease liabilities recorded upon adoption will be based on the present value of future minimum lease payments, the amount of which will depend on the population of leases in effect at the date of adoption. In addition, First Midwest Bank (the "Bank") entered into a sale-leaseback transaction in 2016 that resulted in a deferred gain. Upon adoption of this guidance, the remaining deferred gain, which is estimated to be approximately $50 million after tax, will be recognized immediately as a cumulative-effect adjustment to equity. For additional discussion of the sale-leaseback transaction, see Note 8 " Premises, Furniture, and Equipment " to the Consolidated Financial Statements in the Company's 2017 10-K. Management is completing its evaluation of the guidance and does not expect the adoption of the guidance will materially impact the Company 's results of operations or liquidity, but anticipates a material increase in assets, liabilities, and equity. Measurement of Credit Losses on Financial Instruments: In June of 2016, the FASB issued guidance that will require entities to present financial assets measured at amortized cost at the net amount expected to be collected, considering an entity's current estimate of all expected credit losses. In addition, credit losses relating to available-for-sale debt securities will be required to be recorded through an allowance for credit losses, with changes in credit loss estimates recognized through current earnings. This guidance is effective for annual and interim periods beginning after December 15, 2019. Early adoption is permitted, but not for periods beginning before December 15, 2018. Management is evaluating the guidance and the impact to the Company 's financial condition, results of operations, or liquidity. Accounting for Goodwill Impairment: In January of 2017, the FASB issued guidance that simplifies the accounting for goodwill impairment for all entities. The new guidance eliminates the requirement to calculate the implied fair value of goodwill using the second step of the quantitative two-step goodwill impairment model prescribed under current accounting guidance. Under the new guidance, if a reporting unit's carrying amount exceeds its fair value, an entity will record an impairment charge based on that difference. This guidance is effective for annual and interim goodwill impairment testing dates beginning after December 15, 2019. Early adoption is permitted for annual and interim goodwill impairment testing dates after January 1, 2017. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Premium Amortization on Purchased Callable Debt Securities: In March of 2017, the FASB issued guidance that shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Improvements to Nonemployee Share-based Payment Accounting: In June of 2018, the FASB issued guidance that aligns the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Changes to the Disclosure Requirements for Fair Value Measurement: In August of 2018, the FASB issued guidance that eliminates, modifies, and adds to certain fair value measurement disclosure requirements associated with the three-tiered fair value hierarchy. This guidance is effective for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Changes to the Disclosure Requirements for Defined Benefit Plans: In August of 2018, the FASB issued guidance that makes minor changes and clarifications to the disclosure requirements for entities that sponsor defined benefit plans. This guidance is effective for annual and interim periods beginning after December 15, 2020. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract: In August of 2018, the FASB issued guidance to reduce diversity in practice by clarifying when implementation costs are required to be capitalized in a cloud computing arrangement that is a service contract. This guidance is effective for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS Northern States Financial Corporation On June 6, 2018, the Company entered into a definitive agreement to acquire Northern States Financial Corporation, ("Northern States"), the holding company for NorStates Bank, based in Waukegan, Illinois. On October 12, 2018, the Company completed its acquisition of Northern States. At closing, the Company acquired approximately $550 million in total assets, $465 million in deposits, and $305 million in loans. Under the terms of the merger agreement, the final exchange ratio was determined to be 0.0363 shares of Company common stock for each outstanding share of Northern States common stock, excluding shares held in treasury or otherwise owned by the Company or Northern States. The merger consideration totaled approximately $83 million and resulted in the Company issuing approximately 3.3 million shares of Company common stock. The Company expects that NorStates Bank will be merged with and into First Midwest Bank, with associated systems conversions completed, in early December 2018. Standard Bancshares, Inc. On January 6, 2017, the Company completed its acquisition of Standard Bancshares, Inc. (" Standard "), the holding company for Standard Bank and Trust Company. Pursuant to the terms of the merger agreement, on January 6, 2017, each outstanding share of Standard common stock was canceled and converted into the right to receive 0.4350 of a share of Company common stock. Based on the closing price of shares of Company common stock of $25.34 on that date, as reported by NASDAQ, the value of the merger consideration per share of Standard common stock was $11.02 . Each outstanding Standard stock settled right was redeemed for cash, and each outstanding Standard stock option and each share of Standard phantom stock were canceled and terminated in exchange for the right to receive cash, in each case, pursuant to the terms of the merger agreement. This resulted in an overall transaction value of approximately $580.7 million , which consisted of 21,057,085 shares of Company common stock and $47.1 million in cash. Goodwill of $345.3 million associated with the acquisition was recorded by the Company. All operating systems were converted during the first quarter of 2017. During 2017, the Company finalized the fair value adjustments associated with the Standard transaction. Premier Asset Management LLC On February 28, 2017, the Company completed its acquisition of Premier Asset Management LLC ("Premier"), a registered investment advisor based in Chicago, Illinois. At the close of the acquisition, the Company acquired approximately $550.0 million of trust assets under management. During the first quarter of 2018, the Company finalized the fair value adjustments associated with the Premier transaction.

Securities

Securities	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	SECURITIES The significant accounting policies related to securities are presented in Note 1 , " Summary of Significant Accounting Policies " to the Consolidated Financial Statements in the Company 's 2017 10-K. A summary of the Company's securities portfolio by category and maturity is presented in the following tables. Securities Portfolio (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 49,434 $ — $ (325 ) $ 49,109 $ 46,529 $ — $ (184 ) $ 46,345 U.S. agency securities 143,765 6 (2,517 ) 141,254 157,636 197 (986 ) 156,847 Collateralized mortgage obligations ("CMOs") 1,304,611 103 (46,787 ) 1,257,927 1,113,019 121 (17,954 ) 1,095,186 Other mortgage-backed securities ("MBSs") 462,046 114 (16,495 ) 445,665 373,676 201 (4,334 ) 369,543 Municipal securities 228,048 118 (5,131 ) 223,035 209,558 693 (1,260 ) 208,991 Corporate debt securities 62,888 32 (500 ) 62,420 — — — — Equity securities (1) — — — — 7,408 194 (305 ) 7,297 Total securities available-for-sale $ 2,250,792 $ 373 $ (71,755 ) $ 2,179,410 $ 1,907,826 $ 1,406 $ (25,023 ) $ 1,884,209 Securities Held-to-Maturity Municipal securities $ 12,673 $ — $ (2,158 ) $ 10,515 $ 13,760 $ — $ (1,747 ) $ 12,013 Equity Securities (1) $ 29,046 $ — Trading Securities (1) $ — $ 20,447 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ." Remaining Contractual Maturity of Securities (Dollar amounts in thousands) As of September 30, 2018 Available-for-Sale Held-to-Maturity Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 113,814 $ 111,859 $ 1,631 $ 1,353 After one year to five years 171,155 168,215 4,915 4,078 After five years to ten years 199,166 195,744 2,176 1,806 After ten years — — 3,951 3,278 Securities that do not have a single contractual maturity date 1,766,657 1,703,592 — — Total $ 2,250,792 $ 2,179,410 $ 12,673 $ 10,515 The carrying value of securities available-for-sale that were pledged to secure deposits or for other purposes as permitted or required by law totaled $1.4 billion as of September 30, 2018 and $1.1 billion as of December 31, 2017 . No securities held-to-maturity were pledged as of September 30, 2018 or December 31, 2017 . Securities Available-for-Sale Gains (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Gains on sales of securities: Gross realized gains $ — $ 3,197 $ — $ 3,481 Gross realized losses — — — — Net realized gains on sales of securities — 3,197 — 3,481 Non-cash impairment charges: Other-than-temporary securities impairment ("OTTI") — — — — Net realized gains $ — $ 3,197 $ — $ 3,481 Accounting guidance requires that the credit portion of an OTTI charge be recognized through income. If a decline in fair value below carrying value is not attributable to credit deterioration and the Company does not intend to sell the security or believe it would not be more likely than not required to sell the security prior to recovery, the Company records the non-credit related portion of the decline in fair value in other comprehensive income. There was no outstanding balance of OTTI previously recognized on securities available-for-sale as of either September 30, 2018 or December 31, 2017 . During the quarters and nine months ended September 30, 2018 and 2017 no OTTI was recognized on securities available-for-sale. The following table presents the aggregate amount of unrealized losses and the aggregate related fair values of securities with unrealized losses as of September 30, 2018 and December 31, 2017 . Securities in an Unrealized Loss Position (Dollar amounts in thousands) Less Than 12 Months 12 Months or Longer Total Number of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses As of September 30, 2018 Securities Available-for-Sale U.S. treasury securities 24 $ 38,623 $ 307 $ 10,486 $ 18 $ 49,109 $ 325 U.S. agency securities 75 81,753 1,398 54,161 1,119 135,914 2,517 CMOs 260 610,183 15,445 602,362 31,342 1,212,545 46,787 MBSs 119 215,463 5,396 222,989 11,099 438,452 16,495 Municipal securities 501 140,916 2,762 55,975 2,369 196,891 5,131 Corporate debt securities 8 36,621 500 — — 36,621 500 Total 987 $ 1,123,559 $ 25,808 $ 945,973 $ 45,947 $ 2,069,532 $ 71,755 Securities Held-to-Maturity Municipal securities 8 $ — $ — $ 10,515 $ 2,158 $ 10,515 $ 2,158 As of December 31, 2017 Securities Available-for-Sale U.S. treasury securities 20 $ 19,918 $ 87 $ 26,427 $ 97 $ 46,345 $ 184 U.S. agency securities 72 66,899 300 58,021 686 124,920 986 CMOs 211 365,131 3,265 633,227 14,689 998,358 17,954 MBSs 86 126,136 902 210,017 3,432 336,153 4,334 Municipal securities 265 35,500 479 81,360 781 116,860 1,260 Equity securities (1) 2 391 214 6,386 91 6,777 305 Total 656 $ 613,975 $ 5,247 $ 1,015,438 $ 19,776 $ 1,629,413 $ 25,023 Securities Held-to-Maturity Municipal securities 8 $ — $ — $ 12,013 $ 1,747 $ 12,013 $ 1,747 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ." Substantially all of the Company 's CMO s and other MBSs are either backed by U.S. government-owned agencies or issued by U.S. government-sponsored enterprises. Municipal securities are issued by municipal authorities, and the majority are supported by third-party insurance or some other form of credit enhancement. Management does not believe any of these securities with unrealized losses as of September 30, 2018 represent OTTI related to credit deterioration. These unrealized losses are attributed to changes in interest rates and temporary market movements. The Company does not intend to sell these securities and it is not more likely than not that the Company will be required to sell them before recovery of their amortized cost basis, which may be at maturity.

Loans

Loans	9 Months Ended
	Sep. 30, 2018
Loans and Leases Receivable Disclosure [Abstract]
Loans	LOANS Loans Held-for-Investment The following table presents the Company 's loans held-for-investment by class. Loan Portfolio (Dollar amounts in thousands) As of September 30, December 31, Commercial and industrial $ 3,994,142 $ 3,529,914 Agricultural 432,220 430,886 Commercial real estate: Office, retail, and industrial 1,782,757 1,979,820 Multi-family 698,611 675,463 Construction 632,779 539,820 Other commercial real estate 1,348,831 1,358,515 Total commercial real estate 4,462,978 4,553,618 Total corporate loans 8,889,340 8,514,418 Home equity 853,887 827,055 1-4 family mortgages 888,797 774,357 Installment 418,524 321,982 Total consumer loans 2,161,208 1,923,394 Total loans $ 11,050,548 $ 10,437,812 Deferred loan fees included in total loans $ 5,887 $ 4,986 Overdrawn demand deposits included in total loans 8,239 8,587 The Company primarily lends to community-based and mid-sized businesses, commercial real estate customers, and consumers in its markets. Within these areas, the Company diversifies its loan portfolio by loan type, industry, and borrower. It is the Company 's policy to review each prospective credit to determine the appropriateness and the adequacy of security or collateral prior to making a loan. In the event of borrower default, the Company seeks recovery in compliance with state lending laws, the Company 's lending standards, and credit monitoring and remediation procedures. A discussion of risk characteristics relevant to each portfolio segment is presented in Note 5 , "Loans" to the Consolidated Financial Statements in the Company 's 2017 10-K. Loan Sales The following table presents loan sales for the quarters and nine months ended September 30, 2018 and 2017 . Loan Sales (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Corporate loan sales Proceeds from sales $ 2,868 $ 11,833 $ 15,180 $ 46,770 Less book value of loans sold 2,827 11,512 14,811 45,752 Net gains on corporate loan sales (1) 41 321 369 1,018 1-4 family mortgage loan sales Proceeds from sales $ 62,576 $ 73,889 $ 193,476 $ 190,544 Less book value of loans sold 61,276 72,149 189,370 186,208 Net gains on 1-4 family mortgage loan sales (2) 1,300 1,740 4,106 4,336 Total net gains on loan sales $ 1,341 $ 2,061 $ 4,475 $ 5,354 (1) Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Condensed Consolidated Statements of Income. (2) Net gains on 1-4 family mortgage loan sales are included in mortgage banking income in the Condensed Consolidated Statements of Income. The Company retained servicing responsibilities for a portion of the 1-4 family mortgage loans sold and collects servicing fees equal to a percentage of the outstanding principal balance. For additional disclosure related to the Company's obligations resulting from the sale of certain 1-4 family mortgage loans, see Note 11 , " Commitments, Guarantees, and Contingent Liabilities ."

Acquired and Covered Loans

Acquired and Covered Loans	9 Months Ended
	Sep. 30, 2018
Transfers and Servicing [Abstract]
Acquired and Covered Loans	ACQUIRED AND COVERED LOANS The significant accounting policies related to acquired and covered loans, which are classified as PCI and non-PCI , are presented in Note 1 , " Summary of Significant Accounting Policies ." The following table presents the carrying amount of acquired and covered PCI and non-PCI loans as of September 30, 2018 and December 31, 2017 . Acquired and Covered Loans (1) (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 PCI Non-PCI Total PCI Non-PCI Total Acquired loans $ 98,923 $ 1,121,092 $ 1,220,015 $ 130,694 $ 1,512,664 $ 1,643,358 Covered loans 6,021 7,632 13,653 6,759 11,789 18,548 Total acquired and covered loans $ 104,944 $ 1,128,724 $ 1,233,668 $ 137,453 $ 1,524,453 $ 1,661,906 (1) Included in loans in the Consolidated Statements of Condition. The outstanding balance of PCI loans was $157.2 million and $210.7 million as of September 30, 2018 and December 31, 2017 , respectively. Acquired non-PCI loans that are renewed are no longer classified as acquired loans. These loans totaled $426.4 million and $366.0 million as of September 30, 2018 and December 31, 2017 , respectively. In connection with the FDIC Agreements , the Company recorded an indemnification asset. To maintain eligibility for the loss share reimbursement, the Company is required to follow certain servicing procedures as specified in the FDIC Agreements . The Company was in compliance with those requirements as of September 30, 2018 and December 31, 2017 . Rollforwards of the carrying value of the FDIC indemnification asset for the quarters and nine months ended September 30, 2018 and 2017 are presented in the following table. Changes in the FDIC Indemnification Asset (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 2,710 $ 3,918 $ 3,314 $ 4,522 Amortization (302 ) (302 ) (906 ) (906 ) Change in expected reimbursements from the FDIC for changes in expected credit losses (336 ) (123 ) (161 ) (653 ) Net payments to the FDIC 334 123 159 653 Ending balance $ 2,406 $ 3,616 $ 2,406 $ 3,616 Changes in the accretable yield for acquired and covered PCI loans were as follows. Changes in Accretable Yield (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Beginning balances $ 39,008 $ 39,870 $ 32,957 $ 19,385 Additions — — — 27,316 Accretion (3,008 ) (4,263 ) (9,548 ) (12,106 ) Other (1) 2,672 478 15,263 1,490 Ending balance $ 38,672 $ 36,085 $ 38,672 $ 36,085 (1) Increases represent a rise in the expected future cash flows to be collected over the remaining estimated life of the underlying portfolio, while decreases result from the resolution of certain loans occurring earlier than anticipated. Total accretion on acquired and covered PCI and non-PCI loans for the quarter and nine months ended September 30, 2018 was $4.6 million and $14.1 million , respectively, and $7.6 million and $27.7 million , for the same periods in 2017.

Past Due Loans, Allowance For C

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS	9 Months Ended
	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS	PAST DUE LOANS, ALLOWANCE FOR CREDIT LOSSES, IMPAIRED LOANS, AND TDRS Past Due and Non-accrual Loans The following table presents an aging analysis of the Company 's past due loans as of September 30, 2018 and December 31, 2017 . The aging is determined without regard to accrual status. The table also presents non-performing loans, consisting of non-accrual loans (the majority of which are past due) and loans 90 days or more past due and still accruing interest, as of each balance sheet date. Aging Analysis of Past Due Loans and Non-performing Loans by Class (Dollar amounts in thousands) Aging Analysis (Accruing and Non-accrual) Non-performing Loans Current (1) 30-89 Days Past Due 90 Days or More Past Due Total Past Due Total Loans Non- accrual (2) 90 Days or More Past Due, Still Accruing Interest As of September 30, 2018 Commercial and industrial $ 3,966,088 $ 15,087 $ 12,967 $ 28,054 $ 3,994,142 $ 37,981 $ 1,096 Agricultural 427,702 2,156 2,362 4,518 432,220 2,104 316 Commercial real estate: Office, retail, and industrial 1,767,366 9,640 5,751 15,391 1,782,757 6,685 490 Multi-family 691,698 3,729 3,184 6,913 698,611 3,184 — Construction 628,976 3,595 208 3,803 632,779 208 — Other commercial real estate 1,339,926 5,755 3,150 8,905 1,348,831 4,578 288 Total commercial real estate 4,427,966 22,719 12,293 35,012 4,462,978 14,655 778 Total corporate loans 8,821,756 39,962 27,622 67,584 8,889,340 54,740 2,190 Home equity 848,843 2,995 2,049 5,044 853,887 5,739 9 1-4 family mortgages 885,556 1,287 1,954 3,241 888,797 4,287 41 Installment 414,078 3,737 709 4,446 418,524 — 709 Total consumer loans 2,148,477 8,019 4,712 12,731 2,161,208 10,026 759 Total loans $ 10,970,233 $ 47,981 $ 32,334 $ 80,315 $ 11,050,548 $ 64,766 $ 2,949 As of December 31, 2017 Commercial and industrial $ 3,490,783 $ 34,620 $ 4,511 $ 39,131 $ 3,529,914 $ 40,580 $ 1,830 Agricultural 430,221 280 385 665 430,886 219 177 Commercial real estate: Office, retail, and industrial 1,970,564 3,156 6,100 9,256 1,979,820 11,560 345 Multi-family 672,098 3,117 248 3,365 675,463 377 20 Construction 539,043 198 579 777 539,820 209 371 Other commercial real estate 1,353,263 2,545 2,707 5,252 1,358,515 3,621 317 Total commercial real estate 4,534,968 9,016 9,634 18,650 4,553,618 15,767 1,053 Total corporate loans 8,455,972 43,916 14,530 58,446 8,514,418 56,566 3,060 Home equity 820,099 4,102 2,854 6,956 827,055 5,946 98 1-4 family mortgages 770,120 2,145 2,092 4,237 774,357 4,412 — Installment 319,178 2,407 397 2,804 321,982 — 397 Total consumer loans 1,909,397 8,654 5,343 13,997 1,923,394 10,358 495 Total loans $ 10,365,369 $ 52,570 $ 19,873 $ 72,443 $ 10,437,812 $ 66,924 $ 3,555 (1) PCI loans with an accretable yield are considered current. (2) Includes PCI loans of $688,000 and $763,000 as of September 30, 2018 and December 31, 2017 , respectively, which no longer have an accretable yield as estimates of expected future cash flows have decreased since the acquisition due to credit deterioration. Allowance for Credit Losses The Company maintains an allowance for credit losses at a level deemed adequate by management to absorb estimated losses inherent in the existing loan portfolio. See Note 1 , " Summary of Significant Accounting Policies ," for the accounting policy for the allowance for credit losses. A rollforward of the allowance for credit losses by portfolio segment for the quarters and nine months ended September 30, 2018 and 2017 is presented in the table below. Allowance for Credit Losses by Portfolio Segment (Dollar amounts in thousands) Commercial, Industrial, and Agricultural Office, Retail, and Industrial Multi- family Construction Other Commercial Real Estate Consumer Reserve for Unfunded Commitments Total Allowance for Credit Losses Quarter ended September 30, 2018 Beginning balance $ 60,043 $ 9,062 $ 2,175 $ 2,124 $ 4,631 $ 18,656 $ 1,000 $ 97,691 Charge-offs (6,277 ) (759 ) (1 ) (1 ) (177 ) (2,049 ) — (9,264 ) Recoveries 416 163 — 5 154 512 — 1,250 Net charge-offs (5,861 ) (596 ) (1 ) 4 (23 ) (1,537 ) — (8,014 ) Provision for loan losses and other 6,776 15 200 116 740 3,401 — 11,248 Ending balance $ 60,958 $ 8,481 $ 2,374 $ 2,244 $ 5,348 $ 20,520 $ 1,000 $ 100,925 Quarter ended September 30, 2017 Beginning balance $ 46,271 $ 15,008 $ 2,919 $ 4,094 $ 7,479 $ 16,600 $ 1,000 $ 93,371 Charge-offs (8,935 ) (14 ) — 6 (6 ) (1,617 ) — (10,566 ) Recoveries 698 1,825 2 19 25 331 — 2,900 Net charge-offs (8,237 ) 1,811 2 25 19 (1,286 ) — (7,666 ) Provision for loan losses and other 13,994 (5,129 ) (296 ) 161 (257 ) 1,636 — 10,109 Ending balance $ 52,028 $ 11,690 $ 2,625 $ 4,280 $ 7,241 $ 16,950 $ 1,000 $ 95,814 Nine months ended September 30, 2018 Beginning balance $ 55,791 $ 10,996 $ 2,534 $ 3,481 $ 6,381 $ 16,546 $ 1,000 $ 96,729 Charge-offs (29,609 ) (1,525 ) (5 ) (1 ) (247 ) (6,271 ) — (37,658 ) Recoveries 1,707 286 — 26 552 1,240 — 3,811 Net charge-offs (27,902 ) (1,239 ) (5 ) 25 305 (5,031 ) — (33,847 ) Provision for loan losses and other 33,069 (1,276 ) (155 ) (1,262 ) (1,338 ) 9,005 — 38,043 Ending balance $ 60,958 $ 8,481 $ 2,374 $ 2,244 $ 5,348 $ 20,520 $ 1,000 $ 100,925 Nine months ended September 30, 2017 Beginning balance $ 40,709 $ 17,595 $ 3,261 $ 3,444 $ 7,739 $ 13,335 $ 1,000 $ 87,083 Charge-offs (15,966 ) (141 ) — (38 ) (721 ) (4,837 ) — (21,703 ) Recoveries 2,764 2,808 36 258 205 1,097 — 7,168 Net charge-offs (13,202 ) 2,667 36 220 (516 ) (3,740 ) — (14,535 ) Provision for loan losses and other 24,521 (8,572 ) (672 ) 616 18 7,355 — 23,266 Ending balance $ 52,028 $ 11,690 $ 2,625 $ 4,280 $ 7,241 $ 16,950 $ 1,000 $ 95,814 The table below provides a breakdown of loans and the related allowance for credit losses by portfolio segment as of September 30, 2018 and December 31, 2017 . Loans and Related Allowance for Credit Losses by Portfolio Segment (Dollar amounts in thousands) Loans Allowance for Credit Losses Individually Evaluated for Impairment Collectively Evaluated for Impairment PCI Total Individually Evaluated for Impairment Collectively Evaluated for Impairment PCI Total As of September 30, 2018 Commercial, industrial, and agricultural $ 37,309 $ 4,385,067 $ 3,986 $ 4,426,362 $ 6,659 $ 53,919 $ 380 $ 60,958 Commercial real estate: Office, retail, and industrial 5,639 1,765,584 11,534 1,782,757 1,223 6,049 1,209 8,481 Multi-family 3,573 684,275 10,763 698,611 — 2,134 240 2,374 Construction — 629,427 3,352 632,779 — 2,089 155 2,244 Other commercial real estate 2,496 1,290,122 56,213 1,348,831 22 4,113 1,213 5,348 Total commercial real estate 11,708 4,369,408 81,862 4,462,978 1,245 14,385 2,817 18,447 Total corporate loans 49,017 8,754,475 85,848 8,889,340 7,904 68,304 3,197 79,405 Consumer — 2,142,112 19,096 2,161,208 — 19,003 1,517 20,520 Reserve for unfunded commitments — — — — — 1,000 — 1,000 Total loans $ 49,017 $ 10,896,587 $ 104,944 $ 11,050,548 $ 7,904 $ 88,307 $ 4,714 $ 100,925 As of December 31, 2017 Commercial, industrial, and agricultural $ 38,718 $ 3,909,380 $ 12,702 $ 3,960,800 $ 10,074 $ 45,293 $ 424 $ 55,791 Commercial real estate: Office, retail, and industrial 10,810 1,954,435 14,575 1,979,820 — 9,333 1,663 10,996 Multi-family 621 660,771 14,071 675,463 — 2,436 98 2,534 Construction — 530,977 8,843 539,820 — 3,331 150 3,481 Other commercial real estate 1,468 1,291,723 65,324 1,358,515 — 5,415 966 6,381 Total commercial real estate 12,899 4,437,906 102,813 4,553,618 — 20,515 2,877 23,392 Total corporate loans 51,617 8,347,286 115,515 8,514,418 10,074 65,808 3,301 79,183 Consumer — 1,901,456 21,938 1,923,394 — 15,533 1,013 16,546 Reserve for unfunded commitments — — — — — 1,000 — 1,000 Total loans $ 51,617 $ 10,248,742 $ 137,453 $ 10,437,812 $ 10,074 $ 82,341 $ 4,314 $ 96,729 Loans Individually Evaluated for Impairment The following table presents loans individually evaluated for impairment by class of loan as of September 30, 2018 and December 31, 2017 . PCI loans are excluded from this disclosure. Impaired Loans Individually Evaluated by Class (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Recorded Investment In Recorded Investment In Loans with No Specific Reserve Loans with a Specific Reserve Unpaid Principal Balance Specific Reserve Loans with No Specific Reserve Loans with a Specific Reserve Unpaid Principal Balance Specific Reserve Commercial and industrial $ 7,534 $ 27,934 $ 53,533 $ 6,542 $ 4,234 $ 34,484 $ 53,192 $ 10,074 Agricultural 269 1,572 4,250 117 — — — — Commercial real estate: Office, retail, and industrial 1,636 4,003 6,372 1,223 7,154 3,656 14,246 — Multi-family 3,573 — 3,573 — 621 — 621 — Construction — — — — — — — — Other commercial real estate 1,632 864 2,548 22 1,468 — 1,566 — Total commercial real estate 6,841 4,867 12,493 1,245 9,243 3,656 16,433 — Total impaired loans individually evaluated for impairment $ 14,644 $ 34,373 $ 70,276 $ 7,904 $ 13,477 $ 38,140 $ 69,625 $ 10,074 The following table presents the average recorded investment and interest income recognized on impaired loans by class for the quarters and nine months ended September 30, 2018 and 2017 . PCI loans are excluded from this disclosure. Average Recorded Investment and Interest Income Recognized on Impaired Loans by Class (Dollar amounts in thousands) Quarters Ended September 30, 2018 2017 Average Interest Income Recognized (1) Average Interest Income Recognized (1) Commercial and industrial $ 28,082 $ 123 $ 44,682 $ 368 Agricultural 2,372 — 140 — Commercial real estate: Office, retail, and industrial 6,641 105 12,496 — Multi-family 3,757 11 396 — Construction — — — — Other commercial real estate 2,831 68 1,415 — Total commercial real estate 13,229 184 14,307 — Total impaired loans $ 43,683 $ 307 $ 59,129 $ 368 Nine Months Ended September 30, 2018 2017 Average Interest (1) Average Interest (1) Commercial and industrial $ 34,440 $ 159 $ 32,765 $ 924 Agricultural 2,153 25 348 — Commercial real estate: Office, retail, and industrial 8,867 873 13,680 262 Multi-family 2,132 66 396 28 Construction — — 9 136 Other commercial real estate 2,338 181 1,652 20 Total commercial real estate 13,337 1,120 15,737 446 Total impaired loans $ 49,930 $ 1,304 $ 48,850 $ 1,370 (1) Recorded using the cash basis of accounting. Credit Quality Indicators Corporate loans and commitments are assessed for credit risk and assigned ratings based on various characteristics, such as the borrower's cash flow, leverage, and collateral. Ratings for commercial credits are reviewed periodically. The following tables present credit quality indicators by class for corporate and consumer loans, as of September 30, 2018 and December 31, 2017 . Corporate Credit Quality Indicators by Class (Dollar amounts in thousands) Pass Special Mention (1)(4) Substandard (2)(4) Non-accrual (3) Total As of September 30, 2018 Commercial and industrial $ 3,797,606 $ 134,184 $ 24,371 $ 37,981 $ 3,994,142 Agricultural 411,559 7,591 10,966 2,104 432,220 Commercial real estate: Office, retail, and industrial 1,721,711 19,972 34,389 6,685 1,782,757 Multi-family 683,199 10,139 2,089 3,184 698,611 Construction 601,942 23,477 7,152 208 632,779 Other commercial real estate 1,277,662 48,845 17,746 4,578 1,348,831 Total commercial real estate 4,284,514 102,433 61,376 14,655 4,462,978 Total corporate loans $ 8,493,679 $ 244,208 $ 96,713 $ 54,740 $ 8,889,340 As of December 31, 2017 Commercial and industrial $ 3,388,133 $ 70,863 $ 30,338 $ 40,580 $ 3,529,914 Agricultural 413,946 10,989 5,732 219 430,886 Commercial real estate: Office, retail, and industrial 1,903,737 25,546 38,977 11,560 1,979,820 Multi-family 665,496 7,395 2,195 377 675,463 Construction 521,911 10,184 7,516 209 539,820 Other commercial real estate 1,304,337 29,624 20,933 3,621 1,358,515 Total commercial real estate 4,395,481 72,749 69,621 15,767 4,553,618 Total corporate loans $ 8,197,560 $ 154,601 $ 105,691 $ 56,566 $ 8,514,418 (1) Loans categorized as special mention exhibit potential weaknesses that require the close attention of management since these potential weaknesses may result in the deterioration of repayment prospects in the future. (2) Loans categorized as substandard exhibit well-defined weaknesses that may jeopardize the liquidation of the debt. These loans continue to accrue interest because they are well-secured and collection of principal and interest is expected within a reasonable time. (3) Loans categorized as non-accrual exhibit well-defined weaknesses that may jeopardize the liquidation of the debt or result in a loss if the deficiencies are not corrected. (4) Total special mention and substandard loans includes accruing TDR s of $639,000 as of September 30, 2018 and $657,000 as of December 31, 2017 . Consumer Credit Quality Indicators by Class (Dollar amounts in thousands) Performing Non-accrual Total As of September 30, 2018 Home equity $ 848,148 $ 5,739 $ 853,887 1-4 family mortgages 884,510 4,287 888,797 Installment 418,524 — 418,524 Total consumer loans $ 2,151,182 $ 10,026 $ 2,161,208 As of December 31, 2017 Home equity $ 821,109 $ 5,946 $ 827,055 1-4 family mortgages 769,945 4,412 774,357 Installment 321,982 — 321,982 Total consumer loans $ 1,913,036 $ 10,358 $ 1,923,394 TDR s TDR s are generally performed at the request of the individual borrower and may include forgiveness of principal, reduction in interest rates, changes in payments, and maturity date extensions. The table below presents TDR s by class as of September 30, 2018 and December 31, 2017 . See Note 1, "Summary of Significant Accounting Policies," for the accounting policy for TDR s. TDR s by Class (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Accruing Non-accrual (1) Total Accruing Non-accrual (1) Total Commercial and industrial $ 250 $ 5,603 $ 5,853 $ 264 $ 18,959 $ 19,223 Agricultural — — — — — — Commercial real estate: Office, retail, and industrial — — — — 4,236 4,236 Multi-family 563 — 563 574 149 723 Construction — — — — — — Other commercial real estate 184 — 184 192 — 192 Total commercial real estate 747 — 747 766 4,385 5,151 Total corporate loans 997 5,603 6,600 1,030 23,344 24,374 Home equity 83 352 435 86 738 824 1-4 family mortgages 661 410 1,071 680 451 1,131 Installment — — — — — — Total consumer loans 744 762 1,506 766 1,189 1,955 Total loans $ 1,741 $ 6,365 $ 8,106 $ 1,796 $ 24,533 $ 26,329 (1) These TDR s are included in non-accrual loans in the preceding tables. TDR s are included in the calculation of the allowance for credit losses in the same manner as impaired loans. As of September 30, 2018 and December 31, 2017 , respectively, there were no specific reserves and $2.0 million in specific reserves related to TDR s. There were no material restructurings during the quarter and nine months ended September 30, 2018 . The following table presents a summary of loans that were restructured during the quarter and nine months ended September 30, 2017. Loans Restructured During the Period (Dollar amounts in thousands) Number of Loans Pre- Modification Recorded Investment Funds Disbursed Interest and Escrow Capitalized Charge-offs Post- Modification Recorded Investment Quarter ended September 30, 2017 Commercial and industrial 10 $ 25,811 $ 196 $ — $ 1,736 $ 24,271 Office, retail, and industrial 2 3,656 — — — 3,656 Total TDRs restructured during the period 12 $ 29,467 $ 196 $ — $ 1,736 $ 27,927 Nine months ended September 30, 2017 Commercial and industrial 12 $ 26,733 $ 196 $ — $ 1,736 $ 25,193 Office, retail, and industrial 2 3,656 — — — 3,656 Total TDRs restructured during the period 14 $ 30,389 $ 196 $ — $ 1,736 $ 28,849 Accruing TDR s that do not perform in accordance with their modified terms are transferred to non-accrual. There were no material TDR s that defaulted within twelve months of the restructure date during the quarters and nine months ended September 30, 2018 and 2017 . A rollforward of the carrying value of TDR s for the quarters and nine months ended September 30, 2018 and 2017 is presented in the following table. TDR Rollforward (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Accruing Beginning balance $ 1,760 $ 2,029 $ 1,796 $ 2,291 Additions — 14,897 — 15,819 Net payments (19 ) (1,798 ) (55 ) (1,905 ) Net transfers to non-accrual — (13,315 ) — (14,392 ) Ending balance 1,741 1,813 1,741 1,813 Non-accrual Beginning balance 8,238 3,036 24,533 6,297 Additions — 14,570 355 14,570 Net payments (1,620 ) (127 ) (14,598 ) (4,352 ) Charge-offs (253 ) (2,132 ) (3,925 ) (2,245 ) Net transfers from accruing — 13,315 — 14,392 Ending balance 6,365 28,662 6,365 28,662 Total TDRs $ 8,106 $ 30,475 $ 8,106 $ 30,475 For TDR s to be removed from TDR status in the calendar year after the restructuring, the loans must (i) have an interest rate and terms that reflect market conditions at the time of restructuring, and (ii) be in compliance with the modified terms. Loans that were not restructured at market rates and terms, that are not in compliance with the modified terms, or for which there is a concern about the future ability of the borrower to meet its obligations under the modified terms, continue to be separately reported as restructured until paid in full or charged-off. There were no material commitments to lend additional funds to borrowers with TDR s as of September 30, 2018 or December 31, 2017 .

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Common Share	EARNINGS PER COMMON SHARE The table below displays the calculation of basic and diluted earnings per common share (" EPS "). Basic and Diluted EPS (Amounts in thousands, except per share data) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Net income $ 53,352 $ 38,235 $ 116,462 $ 96,040 Net income applicable to non-vested restricted shares (441 ) (340 ) (992 ) (910 ) Net income applicable to common shares $ 52,911 $ 37,895 $ 115,470 $ 95,130 Weighted-average common shares outstanding: Weighted-average common shares outstanding (basic) 102,178 101,752 102,087 101,307 Dilutive effect of common stock equivalents — 20 5 20 Weighted-average diluted common shares outstanding 102,178 101,772 102,092 101,327 Basic EPS $ 0.52 $ 0.37 $ 1.13 $ 0.94 Diluted EPS $ 0.52 $ 0.37 $ 1.13 $ 0.94 Anti-dilutive shares not included in the computation of diluted EPS (1) — 190 36 242 (1) This amount represents outstanding stock options for which the exercise price is greater than the average market price of the Company's common stock. The final outstanding stock options were exercised during the first quarter of 2018.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The following table presents income tax expense and the effective income tax rate for the quarters and nine months ended September 30, 2018 and 2017 . Income Tax Expense (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Income before income tax expense $ 59,968 $ 55,942 $ 142,605 $ 144,068 Income tax expense: Federal income tax expense $ 2,634 $ 16,355 $ 17,403 $ 41,408 State income tax expense 3,982 1,352 8,740 6,620 Total income tax expense $ 6,616 $ 17,707 $ 26,143 $ 48,028 Effective income tax rate 11.0 % 31.7 % 18.3 % 33.3 % Federal income tax expense and the related effective income tax rate are influenced by the amount of tax-exempt income derived from investment securities and BOLI in relation to pre-tax income and state income taxes. State income tax expense and the related effective tax rate are driven by both the amount of state tax-exempt income in relation to pre-tax income and state tax rules for consolidated/combined reporting and sourcing of income and expense. The decrease in total income tax expense and the effective income tax rate for the quarter and nine months ended September 30, 2018 compared to the same periods in 2017 was driven primarily by $7.8 million of certain income tax benefits aligned with federal income tax reform legislation ("tax reform") and the reduction in the federal income tax rate from 35% to 21%, which became effective in the first quarter of 2018 as a result of tax reform. The Company's accounting policies for the recognition of income taxes in the Consolidated Statements of Financial Condition and Income are included in Note 1 , " Summary of Significant Accounting Policies " and Note 15 , " Income Taxes " to the Consolidated Financial Statements in the Company's 2017 10-K.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES In the ordinary course of business, the Company enters into derivative transactions as part of its overall interest rate risk management strategy. The significant accounting policies related to derivative instruments and hedging activities are presented in Note 1, "Summary of Significant Accounting Policies." Fair Value Hedges The Company hedges the fair value of fixed rate commercial real estate loans using interest rate swaps through which the Company pays fixed amounts and receives variable amounts. These derivative contracts are designated as fair value hedges. Fair Value Hedges (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Gross notional amount outstanding $ 5,083 $ 5,458 Derivative liability fair value in other liabilities (9 ) (101 ) Weighted-average interest rate received 4.11 % 3.38 % Weighted-average interest rate paid 5.96 % 5.96 % Weighted-average maturity (in years) 0.10 0.84 Fair value of derivative (1) $ 15 $ 110 (1) This amount represents the fair value if credit risk related contingent features were triggered. Changes in the fair value of fair value hedges are recognized in other noninterest income in the Condensed Consolidated Statements of Income. Cash Flow Hedges As of September 30, 2018 , the Company hedged $1.1 billion of certain corporate variable rate loans using interest rate swaps through which the Company receives fixed amounts and pays variable amounts. The Company also hedged $1.0 billion of borrowed funds using forward starting interest rate swaps through which the Company receives variable amounts and pays fixed amounts. These transactions allow the Company to add stability to net interest income and manage its exposure to interest rate movements. Forward starting interest rate swaps totaling $710.0 million began on various dates between June of 2015 and May of 2018, and mature between June of 2019 and May of 2020. The remaining forward starting interest rate swaps totaling $320.0 million begin at various dates between December of 2018 and February of 2021 and mature between December of 2021 and February of 2023. The weighted-average fixed interest rate to be paid on these interest rate swaps that have not yet begun was 2.49% as of September 30, 2018 . These derivative contracts are designated as cash flow hedges. Cash Flow Hedges (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Gross notional amount outstanding $ 2,170,000 $ 1,960,000 Derivative asset fair value in other assets (1) 6,009 3,989 Derivative liability fair value in other liabilities (1) (19,197 ) (10,219 ) Weighted-average interest rate received 2.01 % 1.58 % Weighted-average interest rate paid 2.03 % 1.61 % Weighted-average maturity (in years) 1.76 2.25 (1) Certain cash flow hedges are transacted through a clearinghouse ("centrally cleared") and their change in fair value is settled by the counterparties to the transaction, which results in no fair value. Changes in the fair value of cash flow hedges are recorded in accumulated other comprehensive loss on an after-tax basis and are subsequently reclassified to interest income or expense in the period that the forecasted hedged item impacts earnings. As of September 30, 2018 , the Company estimates that $3.3 million will be reclassified from accumulated other comprehensive loss as a decrease to interest income over the next twelve months. Other Derivative Instruments The Company also enters into derivative transactions through capital market products with its commercial customers and simultaneously enters into an offsetting interest rate derivative transaction with third-parties. This transaction allows the Company's customers to effectively convert a variable rate loan into a fixed rate loan. Due to the offsetting nature of these transactions, the Company does not apply hedge accounting treatment. The Company's credit exposure on these derivative transactions results primarily from counterparty credit risk. The credit valuation adjustment (" CVA ") is a fair value adjustment to the derivative to account for this risk. As of September 30, 2018 and December 31, 2017 , the Company's credit exposure was fully secured by the underlying collateral on customer loans and mitigated through netting arrangements with third-parties, therefore, no CVA was recorded. Capital market products income related to commercial customer derivative instruments totaled $1.9 million and $6.3 million for the quarter and nine months ended September 30, 2018 , respectively. There were $2.6 million and $6.2 million of capital market products income for the quarter and nine months ended September 30, 2017 , respectively. Other Derivative Instruments (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Gross notional amount outstanding $ 3,134,222 $ 2,665,358 Derivative asset fair value in other assets (1) 31,044 17,079 Derivative liability fair value in other liabilities (1) (33,832 ) (14,930 ) Fair value of derivative (2) 33,974 15,059 (1) Certain other derivative instruments are centrally cleared and their change in fair value is settled by the counterparties to the transaction, which results in no fair value. (2) This amount represents the fair value if credit risk related contingent features were triggered. The Company occasionally enters into risk participation agreements with counterparty banks to transfer or assume a portion of the credit risk related to customer transactions. The amounts of these instruments were not material for any periods presented. The Company had no other derivative instruments as of September 30, 2018 and December 31, 2017 . The Company does not enter into derivative transactions for purely speculative purposes. The following table presents the impact of derivative instruments on comprehensive income and the reclassification of gains (losses) from accumulated other comprehensive loss to net interest income for the quarters and nine months ended September 30, 2018 and 2017 . Cash Flow Hedge Accounting on AOCI (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Gains (losses) recognized in other comprehensive income Interest rate swaps in interest income $ 2,578 $ 113 $ 13,151 $ 5,465 Interest rate swaps in interest expense (1,577 ) (416 ) (11,620 ) (3,807 ) Reclassification of gains (losses) included in net income Interest rate swaps in interest income $ 857 $ 946 $ 1,504 $ 4,333 Interest rate swaps in interest expense (978 ) (919 ) (2,087 ) (3,142 ) The following table presents the impact of derivative instruments on net interest income for the quarters and nine months ended September 30, 2018 and 2017 . Hedge Income (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Fair Value Hedges Interest rate swaps in interest income $ (24 ) $ (39 ) $ (83 ) $ (129 ) Cash Flow Hedges Interest rate swaps in interest income 857 946 1,504 4,333 Interest rate swaps in interest expense (978 ) (919 ) (2,087 ) (3,142 ) Total cash flow hedges (121 ) 27 (583 ) 1,191 Total net (losses) gains on hedges $ (145 ) $ (12 ) $ (666 ) $ 1,062 Credit Risk Derivative instruments are inherently subject to credit risk, which represents the Company's risk of loss when the counterparty to a derivative contract fails to perform according to the terms of the agreement. Credit risk is managed by limiting and collateralizing the aggregate amount of net unrealized losses by transaction, monitoring the size and the maturity structure of the derivatives, and applying uniform credit standards. Company policy establishes limits on credit exposure to any single counterparty. In addition, the Company established bilateral collateral agreements with derivative counterparties that provide for exchanges of marketable securities or cash to collateralize either party's net losses above a stated minimum threshold. As of September 30, 2018 and December 31, 2017 , these collateral agreements covered 100% of the fair value of the Company's outstanding fair value hedges. Derivative assets and liabilities are presented gross, rather than net, of pledged collateral amounts. Certain derivative instruments are subject to master netting agreements with counterparties. The Company records these transactions at their gross fair values and does not offset derivative assets and liabilities in the Consolidated Statements of Financial Condition. The following table presents the fair value of the Company's derivatives and offsetting positions as of September 30, 2018 and December 31, 2017 . Fair Value of Offsetting Derivatives (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Assets Liabilities Assets Liabilities Gross amounts recognized $ 37,053 $ 53,038 $ 21,068 $ 25,250 Less: amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition (1) 37,053 53,038 21,068 25,250 Gross amounts not offset in the Consolidated Statements of Financial Condition: Offsetting derivative positions (15,177 ) (15,177 ) (16,880 ) (16,880 ) Cash collateral pledged (20,440 ) (3,440 ) — (8,370 ) Net credit exposure $ 1,436 $ 34,421 $ 4,188 $ — (1) Included in other assets or other liabilities in the Consolidated Statements of Financial Condition. As of September 30, 2018 and December 31, 2017 , the Company's derivative instruments generally contained provisions that require the Company's debt to remain above a certain credit rating by each of the major credit rating agencies or that the Company maintain certain capital levels. If the Company's debt were to fall below that credit rating or the Company's capital were to fall below the required levels, it would be in violation of those provisions, and the counterparties to the derivative instruments could terminate the swap transaction and demand cash settlement of the derivative instrument in an amount equal to the derivative liability fair value. As of September 30, 2018 and December 31, 2017 the Company was in compliance with these provisions.

Commitments, Guarantees, and Co

Commitments, Guarantees, and Contingent Liabilities	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments, Guarantees, and Contingent Liabilities	COMMITMENTS, GUARANTEES, AND CONTINGENT LIABILITIES Credit Commitments and Guarantees In the normal course of business, the Company enters into a variety of financial instruments with off-balance sheet risk to meet the financing needs of its customers and to conduct lending activities, including commitments to extend credit and standby and commercial letters of credit. These instruments involve elements of credit and interest rate risk in excess of the amount recognized in the Consolidated Statements of Financial Condition. Contractual or Notional Amounts of Financial Instruments (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Commitments to extend credit: Commercial, industrial, and agricultural $ 1,710,789 $ 1,729,426 Commercial real estate 327,279 377,551 Home equity 547,943 514,973 Other commitments (1) 240,786 244,222 Total commitments to extend credit $ 2,826,797 $ 2,866,172 Letters of credit $ 112,225 $ 128,801 (1) Other commitments includes installment and overdraft protection program commitments. Commitments to extend credit are agreements to lend funds to a customer, subject to contractual terms and covenants. Commitments generally have fixed expiration dates or other termination clauses, variable interest rates, and fee requirements, when applicable. Since many of the commitments are expected to expire without being drawn, the total commitment amounts do not necessarily represent future cash flow requirements. In the event of a customer's non-performance, the Company's credit loss exposure is equal to the contractual amount of the commitments. The credit risk is essentially the same as extending loans to customers for the full contractual amount. The Company uses the same credit policies for credit commitments as its loans and minimizes exposure to credit loss through various collateral requirements. Letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third-party. Letters of credit generally are contingent on the failure of the customer to perform according to the terms of the contract with the third-party and are often issued in favor of a municipality where construction is taking place to ensure the borrower adequately completes the construction. Commercial letters of credit are issued to facilitate transactions between a customer and a third-party based on agreed upon terms. The maximum potential future payments guaranteed by the Company under letters of credit arrangements are equal to the contractual amount of the commitment. If a commitment is funded, the Company may seek recourse through the liquidation of the underlying collateral, including real estate, production plants and property, marketable securities, or receipt of cash. As a result of the sale of certain 1-4 family mortgage loans, the Company is contractually obligated to repurchase early payment default loans or loans that do not meet underwriting requirements at recorded value. In accordance with the sales agreements, there is no limitation to the maximum potential future payments or expiration of the Company's recourse obligation. There were no material loan repurchases during the quarters and nine months ended September 30, 2018 and 2017 . Legal Proceedings In the ordinary course of business, there were certain legal proceedings pending against the Company and its subsidiaries at September 30, 2018 . While the outcome of any legal proceeding is inherently uncertain, based on information currently available, the Company's management does not expect that any liabilities arising from pending legal matters will have a material adverse effect on the Company's business, financial position, results of operations, or cash flows.

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value	FAIR VALUE Fair value represents the amount expected to be received to sell an asset or paid to transfer a liability in its principal or most advantageous market in an orderly transaction between market participants at the measurement date. In accordance with fair value accounting guidance, the Company measures, records, and reports various types of assets and liabilities at fair value on either a recurring or non-recurring basis in the Consolidated Statements of Financial Condition. Those assets and liabilities are presented below in the sections titled "Assets and Liabilities Required to be Measured at Fair Value on a Recurring Basis" and "Assets and Liabilities Required to be Measured at Fair Value on a Non-Recurring Basis." Other assets and liabilities are not required to be measured at fair value in the Consolidated Statements of Financial Condition, but must be disclosed at fair value. See the "Fair Value Measurements of Other Financial Instruments" section of this note. Any aggregation of the estimated fair values presented in this note does not represent the value of the Company. Depending on the nature of the asset or liability, the Company uses various valuation methodologies and assumptions to estimate fair value. GAAP provides a three-tiered fair value hierarchy based on the inputs used to measure fair value. The hierarchy is defined as follows: • Level 1 – Quoted prices in active markets for identical assets or liabilities. • Level 2 – Observable inputs other than level 1 prices, such as quoted prices for similar instruments, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. • Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. These inputs require significant management judgment or estimation, some of which use model-based techniques and may be internally developed. Assets and liabilities are assigned to a level within the fair value hierarchy based on the lowest level of significant input used to measure fair value. Assets and liabilities may change levels within the fair value hierarchy due to market conditions or other circumstances. Those transfers are recognized on the date of the event that prompted the transfer. There were no transfers of assets or liabilities required to be measured at fair value on a recurring basis between levels of the fair value hierarchy during the periods presented. Assets and Liabilities Required to be Measured at Fair Value on a Recurring Basis The following table provides the fair value for assets and liabilities required to be measured at fair value on a recurring basis in the Consolidated Statements of Financial Condition by level in the fair value hierarchy. Recurring Fair Value Measurements (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets Trading securities: Money market funds $ — $ — $ — $ 1,685 $ — $ — Mutual funds — — — 18,762 — — Total trading securities (1) — — — 20,447 — — Equity securities (1) 22,078 6,968 — — — — Securities available-for-sale (1) U.S. treasury securities 49,109 — — 46,345 — — U.S. agency securities — 141,254 — — 156,847 — CMOs — 1,257,927 — — 1,095,186 — MBSs — 445,665 — — 369,543 — Municipal securities — 223,035 — — 208,991 — Corporate debt securities — 62,420 — — — — Equity securities — — — — 7,297 — Total securities available-for-sale 49,109 2,130,301 — 46,345 1,837,864 — Mortgage servicing rights ("MSRs") (2) — — 6,817 — — 5,894 Derivative assets (2) — 37,053 — — 21,068 — Liabilities Derivative liabilities (3) $ — $ 53,038 $ — $ — $ 25,250 $ — (1) As a result of recently adopted accounting guidance, equity securities are no longer presented within trading securities or securities available-for-sale for the prior period and are now presented within equity securities for the current period. For further discussion of this guidance, see Note 2 of "Notes to the Condensed Consolidated Financial Statements" in Item 1 of this Form 10-Q. (2) Included in other assets in the Consolidated Statements of Financial Condition. (3) Included in other liabilities in the Consolidated Statements of Financial Condition. The following sections describe the specific valuation techniques and inputs used to measure financial assets and liabilities at fair value. Equity Securities The Company's equity securities consist primarily of community development investments and certain diversified investment securities held in a grantor trust for participants in the Company's nonqualified deferred compensation plan that are invested in money market and mutual funds. The fair value of community development investments is based on quoted prices in active markets or market prices for similar securities obtained from external pricing services or dealer market participants and is classified in level 2 of the fair value hierarchy. The fair value of the money market and mutual funds is based on quoted market prices in active exchange markets and is classified in level 1 of the fair value hierarchy. Securities Available-for-Sale The Company's securities available-for-sale are primarily fixed income instruments that are not quoted on an exchange, but may be traded in active markets. The fair values for these securities are based on quoted prices in active markets or market prices for similar securities obtained from external pricing services or dealer market participants and are classified in level 2 of the fair value hierarchy. The fair value of U.S. treasury securities is based on quoted market prices in active exchange markets and is classified in level 1 of the fair value hierarchy. Quarterly, the Company evaluates the methodologies used by its external pricing services to estimate the fair value of these securities to determine whether the valuations represent an exit price in the Company's principal markets. MSR s The Company services loans for others totaling $624.9 million and $607.0 million as of September 30, 2018 and December 31, 2017 , respectively. These loans are owned by third-parties and are not included in the Consolidated Statements of Financial Condition. The Company determines the fair value of MSR s by estimating the present value of expected future cash flows associated with the mortgage loans being serviced and classifies them in level 3 of the fair value hierarchy. The following table presents the ranges of significant, unobservable inputs used by the Company to determine the fair value of MSR s as of September 30, 2018 and December 31, 2017 . Significant Unobservable Inputs Used in the Valuation of MSR s As of September 30, 2018 December 31, 2017 Prepayment speed 6.6 % - 13.1% 4.2 % - 13.1% Maturity (months) 2 - 106 6 - 92 Discount rate 9.5 % - 12.0% 9.5 % - 12.0% The impact of changes in these key inputs could result in a significantly higher or lower fair value measurement for MSR s. Significant increases in expected prepayment speeds and discount rates have negative impacts on the valuation. Higher maturity assumptions have a favorable effect on the estimated fair value. A rollforward of the carrying value of MSR s for the quarters and nine months ended September 30, 2018 and 2017 is presented in the following table. Carrying Value of MSR s (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 6,671 $ 5,925 $ 5,894 $ 6,120 New MSRs 324 161 893 522 Total gains (losses) included in earnings (1) : Changes in valuation inputs and assumptions 65 (121 ) 627 (209 ) Other changes in fair value (2) (243 ) (199 ) (597 ) (667 ) Ending balance $ 6,817 $ 5,766 $ 6,817 $ 5,766 Contractual servicing fees earned (1) $ 375 $ 379 $ 1,122 $ 1,158 (1) Included in mortgage banking income in the Condensed Consolidated Statements of Income and related to assets held as of September 30, 2018 and 2017 . (2) Primarily represents changes in expected future cash flows due to payoffs and paydowns. Derivative Assets and Derivative Liabilities The Company enters into interest rate swaps and derivative transactions with commercial customers. These derivative transactions are executed in the dealer market, and pricing is based on market quotes obtained from the counterparties. The market quotes were developed using market observable inputs, which primarily include LIBOR. Therefore, derivatives are classified in level 2 of the fair value hierarchy. For its derivative assets and liabilities, the Company also considers non-performance risk, including the likelihood of default by itself and its counterparties, when evaluating whether the market quotes from the counterparty are representative of an exit price. Assets and Liabilities Required to be Measured at Fair Value on a Non-Recurring Basis The following table provides the fair value for each class of assets and liabilities required to be measured at fair value on a non-recurring basis in the Consolidated Statements of Financial Condition by level in the fair value hierarchy. Non-Recurring Fair Value Measurements (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Collateral-dependent impaired loans (1) $ — $ — $ 28,077 $ — $ — $ 33,240 OREO (2) — — 7,075 — — 12,340 Loans held-for-sale (3) — — 6,020 — — 21,098 Assets held-for-sale (4) — — 4,659 — — 2,208 (1) Includes impaired loans with charge-offs and impaired loans with a specific reserve during the periods presented. (2) Includes OREO with fair value adjustments subsequent to initial transfer that occurred during the periods presented. (3) Included in other assets in the Consolidated Statements of Financial Condition. (4) Included in premises, furniture, and equipment in the Consolidated Statements of Financial Condition. Collateral-Dependent Impaired Loans Certain collateral-dependent impaired loans are subject to fair value adjustments to reflect the difference between the carrying value of the loan and the value of the underlying collateral. The fair values of collateral-dependent impaired loans are primarily determined by current appraised values of the underlying collateral. Based on the age and/or type, appraisals may be adjusted in the range of 0% to 15% . In certain cases, an internal valuation may be used when the underlying collateral is located in areas where comparable sales data is limited or unavailable. Accordingly, collateral-dependent impaired loans are classified in level 3 of the fair value hierarchy. Collateral-dependent impaired loans for which the fair value is greater than the recorded investment are not measured at fair value in the Consolidated Statements of Financial Condition and are not included in this disclosure. OREO The fair value of OREO is measured using the current appraised value of the properties. In certain circumstances, a current appraisal may not be available or may not represent an accurate measurement of the property's fair value due to outdated market information or other factors. In these cases, the fair value is determined based on the lower of the (i) most recent appraised value, (ii) broker price opinion, (iii) current listing price, or (iv) signed sales contract. Given these valuation methods, OREO is classified in level 3 of the fair value hierarchy. Loans Held-for-Sale As of September 30, 2018 and December 31, 2017 , loans held-for-sale consists of 1-4 family mortgage loans, which were originated with the intent to sell. These loans were recorded in the held-for-sale category at the contract price and, accordingly, are classified in level 3 of the fair value hierarchy. Assets Held-for-Sale Assets held-for-sale as of September 30, 2018 and December 31, 2017 consists of former branches that are no longer in operation and parcels of land previously purchased for expansion. These properties are being actively marketed and were transferred into the held-for-sale category at their fair value as determined by current appraisals. Based on these valuation methods, they are classified in level 3 of the fair value hierarchy. Financial Instruments Not Required to be Measured at Fair Value For certain financial instruments that are not required to be measured at fair value in the Consolidated Statements of Financial Condition, the Company must disclose the estimated fair values and the level within the fair value hierarchy as shown in the following table. Fair Value Measurements of Other Financial Instruments (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Fair Value Hierarchy Level Carrying Amount Fair Value Carrying Amount Fair Value Assets Cash and due from banks 1 $ 185,239 $ 185,239 $ 192,800 $ 192,800 Interest-bearing deposits in other banks 2 111,360 111,360 153,770 153,770 Securities held-to-maturity 2 12,673 10,515 13,760 12,013 FHLB and FRB stock 2 87,728 87,728 69,708 69,708 Loans 3 10,953,029 10,587,311 10,345,397 10,059,992 Investment in BOLI 3 284,074 284,074 279,900 279,900 Accrued interest receivable 3 51,856 51,856 45,261 45,261 Other interest-earning assets 3 33 33 228 228 Liabilities Deposits 2 $ 11,527,114 $ 11,505,442 $ 11,053,325 $ 11,038,819 Borrowed funds 2 1,073,546 1,073,546 714,884 714,884 Senior and subordinated debt 2 195,595 209,917 195,170 208,666 Accrued interest payable 2 6,406 6,406 4,704 4,704 Management uses various methodologies and assumptions to determine the estimated fair values of the financial instruments in the table above. The fair value estimates are made at a discrete point in time based on relevant market information and consider management's judgments regarding future expected economic conditions, loss experience, and specific risk characteristics of the financial instruments. Loans include the FDIC indemnification asset and net loans, which consists of loans held-for-investment, acquired loans, and the allowance for loan losses. As of both September 30, 2018 and December 31, 2017 , the Company estimated the fair value of lending commitments outstanding to be immaterial.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation – The accompanying unaudited condensed consolidated interim financial statements ("consolidated financial statements") of First Midwest Bancorp, Inc. (the " Company "), a Delaware corporation, were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (" SEC ") for quarterly reports on Form 10-Q and reflect all adjustments that management deems necessary for the fair presentation of the financial position and results of operations for the periods presented. The results of operations for the quarter and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . The accounting and reporting policies of the Company and its subsidiaries conform to U.S. generally accepted accounting principles (" GAAP ") and general practices within the banking industry. The accompanying consolidated financial statements do not include certain information and note disclosures required by GAAP for complete annual financial statements. Therefore, these financial statements should be read in conjunction with the Company 's 2017 Annual Report on Form 10-K (" 2017 10-K"). The Company uses the accrual basis of accounting for financial reporting purposes.
Reclassification	Certain reclassifications were made to prior year amounts to conform to the current year presentation.
Use of Estimates	Use of Estimates – The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates and assumptions are based on the best available information, actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation – The accompanying consolidated financial statements include the financial position and results of operations of the Company and its subsidiaries after elimination of all significant intercompany accounts and transactions. Assets held in a fiduciary or agency capacity are not assets of the Company or its subsidiaries and are not included in the consolidated financial statements.
Business Combinations	Business Combinations – Business combinations are accounted for under the acquisition method of accounting. Assets acquired and liabilities assumed are recorded at their estimated fair values as of the date of acquisition, with any excess of the purchase price of the acquisition over the fair value of the identifiable net tangible and intangible assets acquired recorded as goodwill. Alternatively, a gain is recorded if the fair value of assets purchased exceeds the fair value of liabilities assumed and consideration paid. The results of operations of the acquired business are included in the Condensed Consolidated Statements of Income from the effective date of the acquisition.
Loans	Loans – Loans held-for-investment are loans that the Company intends to hold until they are paid in full and are carried at the principal amount outstanding, including certain net deferred loan origination fees. Loan origination fees, commitment fees, and certain direct loan origination costs are deferred, and the net amount is amortized as a yield adjustment over the contractual life of the related loans or commitments and included in interest income. Fees related to letters of credit are amortized into fee income over the contractual life of the commitment. Other credit-related fees are recognized as fee income when earned. The Company 's net investment in direct financing leases is included in loans and consists of future minimum lease payments and estimated residual values, net of unearned income. Interest income on loans is accrued based on principal amounts outstanding. Loans held-for-sale are carried at the lower of aggregate cost or fair value and included in other assets in the Consolidated Statements of Financial Condition.
Acquired and Covered Loans	Acquired and Covered Loans – Covered loans consists of loans acquired by the Company in Federal Deposit Insurance Corporation (" FDIC ")-assisted transactions, which are covered by loss share agreements with the FDIC (the " FDIC Agreements "), under which the FDIC reimburses the Company for the majority of the losses and eligible expenses related to these assets during the coverage period. Acquired loans consist of all other loans that were acquired in business combinations that are not covered by the FDIC Agreements. Certain loans that were previously classified as covered loans are no longer covered under the FDIC Agreements, and are included in acquired loans. Covered loans and acquired loans are included within loans held-for-investment. Acquired and covered loans are separated into (i) non-purchased credit impaired (" non-PCI ") and (ii) purchased credit impaired (" PCI ") loans. Non-PCI loans include loans that did not have evidence of credit deterioration since origination at the acquisition date. PCI loans include loans that had evidence of credit deterioration since origination and for which it was probable at acquisition that the Company would not collect all contractually required principal and interest payments. Evidence of credit deterioration was evaluated using various indicators, such as past due and non-accrual status. Leases and revolving loans do not qualify to be accounted for as PCI loans and are accounted for as non-PCI loans. The acquisition adjustment related to non-PCI loans is amortized into interest income over the contractual life of the related loans. If an acquired non-PCI loan is renewed subsequent to the acquisition date, any remaining acquisition adjustment is accreted into interest income and the loan is considered a new loan that is no longer classified as an acquired loan. PCI loans are accounted for based on estimates of expected future cash flows. To estimate the fair value, the Company generally aggregates purchased consumer loans and commercial loans into pools of loans with common risk characteristics, such as delinquency status, credit score, and internal risk ratings. The fair values of larger balance commercial loans are estimated on an individual basis. Expected future cash flows in excess of the fair value of loans at the purchase date ("accretable yield") are recorded as interest income over the life of the loans if the timing and amount of the expected future cash flows can be reasonably estimated. The non-accretable yield represents the difference between contractually required payments and the expected future cash flows determined at acquisition. Subsequent increases in expected future cash flows are offset against the allowance for credit losses to the extent an allowance has been established or otherwise recognized as interest income prospectively. The present value of any decreases in expected future cash flows is recognized by recording a charge-off through the allowance for loan losses or providing an allowance for loan losses.
90-Days Past Due Loans	90-Days Past Due Loans – The Company 's accrual of interest on loans is generally discontinued at the time the loan is 90 days past due unless the credit is sufficiently collateralized and in the process of renewal or collection.
Non-accrual Loans	Non-accrual Loans – Generally, corporate loans are placed on non-accrual status (i) when either principal or interest payments become 90 days or more past due unless the credit is sufficiently collateralized and in the process of renewal or collection, or (ii) when an individual analysis of a borrower's creditworthiness warrants a downgrade to non-accrual regardless of past due status. When a loan is placed on non-accrual status, unpaid interest credited to income in the current year is reversed, and unpaid interest accrued in prior years is charged against the allowance for loan losses. After the loan is placed on non-accrual status, all debt service payments are applied to the principal on the loan. Future interest income may only be recorded on a cash basis after recovery of principal is reasonably assured. Non-accrual loans are returned to accrual status when the financial position of the borrower and other relevant factors indicate that the Company will collect all principal and interest. Commercial loans and loans secured by real estate are charged-off when deemed uncollectible. A loss is recorded if the net realizable value of the underlying collateral is less than the outstanding principal and interest. Consumer loans that are not secured by real estate are subject to mandatory charge-off at a specified delinquency date and are usually not classified as non-accrual prior to being charged-off. Closed-end consumer loans, which include installment, automobile, and single payment loans, are usually charged-off no later than the end of the month in which the loan becomes 120 days past due. PCI loans are generally considered accruing loans unless reasonable estimates of the timing and amount of expected future cash flows cannot be determined. Loans without reasonable future cash flow estimates are classified as non-accrual loans, and interest income is not recognized on those loans until the timing and amount of the expected future cash flows can be reasonably determined.
Troubled Debt Restructurings (“TDRs”)	Troubled Debt Restructurings ( " TDR s" ) – A restructuring is considered a TDR when (i) the borrower is experiencing financial difficulties, and (ii) the creditor grants a concession, such as forgiveness of principal, reduction of the interest rate, changes in payments, or extension of the maturity date. Loans are not classified as TDR s when the modification is short-term or results in an insignificant delay in payments. The Company 's TDR s are determined on a case-by-case basis. The Company does not accrue interest on a TDR unless it believes collection of all principal and interest under the modified terms is reasonably assured. For a TDR to begin accruing interest, the borrower must demonstrate some level of past performance and the future capacity to perform under the modified terms. Generally, six months of consecutive payment performance under the restructured terms is required before a TDR is returned to accrual status. However, the period could vary depending on the individual facts and circumstances of the loan. An evaluation of the borrower's current creditworthiness is used to assess the borrower's capacity to repay the loan under the modified terms. This evaluation includes an estimate of expected future cash flows, evidence of strong financial position, and estimates of the value of collateral, if applicable. For TDR s to be removed from TDR status in the calendar year after the restructuring, the loans must (i) have an interest rate and terms that reflect market conditions at the time of restructuring, and (ii) be in compliance with the modified terms. If the loan was restructured at below market rates and terms, it continues to be separately reported as restructured until it is paid in full or charged-off.
Impaired Loans	Impaired Loans – Impaired loans consist of corporate non-accrual loans and TDR s. A loan is considered impaired when it is probable that the Company will not collect all contractual principal and interest. With the exception of accruing TDR s, impaired loans are classified as non-accrual and are exclusive of smaller homogeneous loans, such as home equity, 1-4 family mortgages, and installment loans. Impaired loans with balances under a specified threshold are not individually evaluated for impairment. For all other impaired loans, impairment is measured by comparing the estimated value of the loan to the recorded book value. The value of collateral-dependent loans is based on the fair value of the underlying collateral, less costs to sell. The value of other loans is measured using the present value of expected future cash flows discounted at the loan's initial effective interest rate.
Allowance for Credit/Loan Losses and Reserve for Unfunded Commitments	Allowance for Credit Losses – The allowance for credit losses is comprised of the allowance for loan losses and the reserve for unfunded commitments, and is maintained by management at a level believed adequate to absorb estimated losses inherent in the existing loan portfolio. Determination of the allowance for credit losses is subjective since it requires significant estimates and management judgment, including the amounts and timing of expected future cash flows on impaired loans, estimated losses on pools of homogeneous loans, consideration of current economic trends, and other factors. Loans deemed to be uncollectible are charged-off against the allowance for loan losses, while recoveries of amounts previously charged-off are credited to the allowance for loan losses. Additions to the allowance for loan losses are charged to expense through the provision for loan losses. The amount of provision depends on a number of factors, including net charge-off levels, loan growth, changes in the composition of the loan portfolio, and the Company 's assessment of the allowance for loan losses based on the methodology discussed below. Allowance for Loan Losses – The allowance for loan losses consists of (i) specific reserves for individual loans where the recorded investment exceeds the value, (ii) an allowance based on a loss migration analysis that uses historical credit loss experience for each loan category, and (iii) an allowance based on other internal and external qualitative factors. The specific reserves component of the allowance for loan losses is based on a periodic analysis of impaired loans exceeding a fixed dollar amount. If the value of an impaired loan is less than the recorded book value, the Company either establishes a valuation allowance (i.e., a specific reserve) equal to the excess of the book value over the collateral value of the loan as a component of the allowance for loan losses or charges off the amount if it is a confirmed loss. The general reserve component is based on a loss migration analysis, which examines actual loss experience by loan category for a rolling 8-quarter period and the related internal risk rating for corporate loans. The loss migration analysis is updated quarterly, primarily using actual loss experience. This component is then adjusted based on management's consideration of many internal and external qualitative factors, including: • Changes in the composition of the loan portfolio, trends in the volume of loans, and trends in delinquent and non-accrual loans that could indicate that historical trends do not reflect current conditions. • Changes in credit policies and procedures, such as underwriting standards and collection, charge-off, and recovery practices. • Changes in the experience, ability, and depth of credit management and other relevant staff. • Changes in the quality of the Company 's loan review system and Board of Directors oversight. • The effect of any concentration of credit and changes in the level of concentrations, such as loan type or risk rating. • Changes in the value of the underlying collateral for collateral-dependent loans. • Changes in the national and local economy that affect the collectability of various segments of the portfolio. • The effect of other external factors, such as competition and legal and regulatory requirements, on the Company 's loan portfolio. The allowance for loan losses also consists of an allowance on acquired and covered non-PCI and PCI loans. No allowance for loan losses is recorded on acquired loans at the acquisition date. Subsequent to the acquisition date, an allowance for credit losses is established as necessary to reflect credit deterioration. The acquired non-PCI allowance is based on management's evaluation of the acquired non-PCI loan portfolio giving consideration to the current portfolio balance, including the remaining acquisition adjustments, maturity dates, and overall credit quality. The allowance for covered non-PCI loans is calculated in the same manner as the general reserve component based on a loss migration analysis as discussed above. The acquired and covered PCI allowance reflects the difference between the carrying value and the discounted expected future cash flows of the acquired and covered PCI loans. On a periodic basis, the adequacy of this allowance is determined through a re-estimation of expected future cash flows on all of the outstanding acquired and covered PCI loans using either a probability of default/loss given default (" PD/LGD ") methodology or a specific review methodology. The PD/LGD model is a loss model that estimates expected future cash flows using a probability of default curve and loss given default estimates. Acquired non-PCI loans that have renewed subsequent to the respective acquisition dates are no longer classified as acquired loans. Instead, they are included in the general loan population and allocated an allowance based on a loss migration analysis. Reserve for Unfunded Commitments – The Company also maintains a reserve for unfunded commitments, including letters of credit, for the risk of loss inherent in these arrangements. The reserve for unfunded commitments is estimated using the loss migration analysis from the allowance for loan losses, adjusted for probabilities of future funding requirements. The reserve for unfunded commitments is included in other liabilities in the Consolidated Statements of Financial Condition. The establishment of the allowance for credit losses involves a high degree of judgment given the difficulty of assessing the factors impacting loan repayment and estimating the timing and amount of losses. While management utilizes its best judgment and information available, the adequacy of the allowance for credit losses depends on a variety of factors beyond the Company 's control, including the performance of its loan portfolio, the economy, changes in interest rates and property values, and the interpretation of loan risk classifications by regulatory authorities.
Derivative Financial Instruments	Derivative Financial Instruments – To provide derivative products to customers and in the ordinary course of business, the Company enters into derivative transactions as part of its overall interest rate risk management strategy to minimize significant unplanned fluctuations in earnings and expected future cash flows caused by interest rate volatility. All derivative instruments are recorded at fair value as either other assets or other liabilities in the Consolidated Statements of Financial Condition. Subsequent changes in a derivative's fair value are recognized in earnings unless specific hedge accounting criteria are met. On the date the Company enters into a derivative contract, the derivative is designated as a fair value hedge, a cash flow hedge, or a non-hedge derivative instrument. Fair value hedges are designed to mitigate exposure to changes in the fair value of an asset or liability attributable to a particular risk, such as interest rate risk. Cash flow hedges are designed to mitigate exposure to variability in expected future cash flows to be received or paid related to an asset, liability, or other type of forecasted transaction. The Company formally documents all relationships between hedging instruments and hedged items, including its risk management objective and strategy at inception. At the hedge's inception, a formal assessment is performed to determine the effectiveness of the derivative in offsetting changes in the fair values or expected future cash flows of the hedged items in the current period and prospectively. If a derivative instrument designated as a hedge is terminated or ceases to be highly effective, hedge accounting is discontinued prospectively, and the gain or loss is amortized into earnings. For fair value hedges, the gain or loss is amortized over the remaining life of the hedged asset or liability. For cash flow hedges, the gain or loss is amortized over the same period that the forecasted hedged transactions impact earnings. If the hedged item is disposed of, any fair value adjustments are included in the gain or loss from the disposition of the hedged item. If the forecasted transaction is no longer probable, the gain or loss is included in earnings immediately. For fair value hedges, changes in the fair value of the derivative instruments, as well as changes in the fair value of the hedged item, are recognized in earnings in the same income statement line item as the earnings effect of the hedged item. For cash flow hedges, the effective portion of the change in fair value of the derivative instrument is reported as a component of accumulated other comprehensive loss and is reclassified to earnings when the hedged transaction is reflected in earnings.
Recent Accounting Pronouncements	Adopted Accounting Pronouncements Revenue from Contracts with Customers: In May of 2014, the Financial Accounting Standards Board ("FASB") issued guidance that requires an entity to 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. In March of 2016, the FASB issued an amendment to this guidance to clarify the implementation of guidance on principal versus agent consideration. Additional amendments to clarify the implementation guidance on the identification of performance obligations and licensing were issued in April of 2016 and narrow-scope improvements and practical expedients were issued in May of 2016. The guidance is effective for annual and interim reporting periods beginning on or after December 15, 2017, and must be applied either retrospectively or using the modified retrospective approach. The Company's revenue is comprised of net interest income on financial assets and liabilities, which is excluded from the scope of this guidance, and noninterest income. The primary sources of revenue within noninterest income are service charges on deposit accounts, wealth management fees, card-based fees, and merchant servicing fees. The adoption of this guidance on January 1, 2018, using the modified retrospective approach, affected how the Company presents merchant servicing fees, merchant card expenses, card-based fees, and cardholder expenses, which are presented on a gross basis within noninterest income and noninterest expense for the prior period and are presented on a net basis within noninterest income for the current period. Total expenses of $4.2 million and $11.9 million for the quarter and nine months ended September 30, 2018 were netted in noninterest income. The adoption of this guidance did not impact net income; therefore, a cumulative effect adjustment to opening retained earnings was not deemed necessary. Consistent with the modified retrospective approach, the Company did not adjust prior period amounts for the reclassification of merchant card expenses and cardholder expenses. A description of the Company's revenue streams accounted for under the scope of this guidance follows: Service charges on deposit accounts – Service charges on deposit accounts consist of account analysis fees (net fees earned on analyzed business and public checking accounts), monthly service fees, and other deposit account related fees. The Company's performance obligation for account analysis fees and monthly service fees is generally satisfied, and the related revenue recognized, over the period in which the service is provided. Other deposit account related fees are largely transactional based and, therefore, the Company's performance obligation is satisfied, and related revenue recognized, at a point in time. Payment for service charges on deposit accounts is primarily received as a direct charge to customers' accounts. As a result of the adoption of this guidance, there was no impact to the method of recognizing revenue related to service charges on deposit accounts for the quarter and nine months ended September 30, 2018 . Wealth management fees – Wealth management fees represents quarterly fees due from wealth management customers as consideration for managing the customers' assets. Wealth management services include custody of assets, investment management, escrow services, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed each quarter, which is generally the time that payment is received. Also included are fees received from a third-party broker-dealer as part of a revenue-sharing agreement. These fees are paid to us by the third-party on a quarterly basis and recognized ratably throughout the quarter as our performance obligation is satisfied. As a result of the adoption of this guidance, there was no impact to the method of recognizing revenue related to wealth management fees for the quarter and nine months ended September 30, 2018 . Card-based fees, net – Card-based fees, net consists of debit and credit card interchange fees for processing transactions, as well as various fees for automated teller machine ("ATM") and point-of-sale transactions processed through the related networks. Interchange, ATM, and point-of-sale fees from cardholder transactions represent a percentage of the underlying transaction value or a flat fee and are recognized daily in connection with the transaction processing services provided to the cardholder. Card-based fees are presented net of certain contract costs associated with the debit, credit and ATM card interchange networks. As a result of the adoption of this guidance, $1.9 million and $5.5 million of cardholder expenses are netted against card-based fees for the quarter and nine months ended September 30, 2018 , respectively. Merchant servicing fees, net – Merchant servicing fees, net is included in other service charges, commissions, and fees in the Consolidated Statements of Income. The Company acts in an agency capacity with respect to its merchants to process their debit and credit card transactions, deriving revenue from assisting another entity in transactions with the Company's customers. Merchant servicing fees represent a percentage of the underlying net transaction volume or a flat fee and are recognized monthly. Merchant servicing fees are presented net of certain contract costs associated with the third-party merchant processing. As a result of the adoption of this guidance, $2.3 million and $6.4 million of merchant card expenses are netted against merchant servicing fees for the quarter and nine months ended September 30, 2018 , respectively. Amendments to Guidance on Classifying and Measuring Financial Instruments: In January of 2016, the FASB issued guidance that will require entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value. Any subsequent changes in fair value will be recognized in net income unless the investments qualify for a new practicability exception. Equity securities totaling $29.0 million are no longer classified as trading securities or securities available-for-sale. This guidance also requires entities to adjust the fair value disclosures for financial instruments carried at amortized cost from an entry price to an exit price. No changes were made to the guidance for classifying and measuring investments in debt securities and loans. Except as discussed above, the adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Classification of Certain Cash Receipts and Cash Payments: In August of 2016, the FASB issued guidance clarifying certain cash flow presentation and classification issues to reduce diversity in practice. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Income Taxes: In October of 2016, the FASB issued guidance that requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Clarifying the Definition of a Business: In January of 2017, the FASB issued guidance that clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. The adoption of this guidance on January 1, 2018 did not impact the Company's financial condition, results of operations, or liquidity. Presentation of Defined Benefit Retirement Plan Costs: In March of 2017, the FASB issued guidance that changes how employers that sponsor defined pension and or other postretirement benefit plans present the net periodic benefit cost in the income statement. Employers are required to present the service cost component of the net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. Other components of net periodic benefit cost are required to be presented separately from the line item(s) that includes the service cost. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Share-based Payment Award Modifications: In May of 2017, the FASB issued guidance to reduce diversity in practice by clarifying when changes to the terms or conditions of a share-based payment award must be accounted for as a modification. The adoption of this guidance on January 1, 2018 did not materially impact the Company's financial condition, results of operations, or liquidity. Derivatives and Hedging: In August of 2017, the FASB issued guidance to better align the financial reporting related to hedging activities with the economic objectives of those activities and to simplify the application of current hedge accounting guidance. Entities are required to apply the guidance using a modified retrospective method as of the period of adoption. This guidance is effective for annual and interim periods beginning after December 31, 2018. Early adoption is permitted, and the Company elected to do so on January 1, 2018, which did not materially impact the Company's financial condition, results of operations, or liquidity. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income: In February of 2018, the FASB issued guidance that requires a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017 . Entities electing the reclassification are required to apply the guidance either at the beginning of the period of adoption or retrospectively for all periods impacted. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted and the Company elected to do so on January 1, 2018, which resulted in the reclassification of $6.8 million of stranded tax effects from accumulated other comprehensive loss to retained earnings as of the beginning of the period of adoption. Accounting Pronouncements Pending Adoption Leases: In February of 2016, the FASB issued guidance to increase transparency and comparability across entities for leasing arrangements. This guidance requires lessees to recognize assets and liabilities for most leases. For lessors, this guidance modifies the lease classification criteria and the accounting for sales-type and direct financing leases. In addition, this guidance clarifies criteria for the determination of whether a contract is or contains a lease. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. The Company will adopt this guidance on January 1, 2019, which will result in the recognition of right-of-use assets and associated lease liabilities for its operating leases. The amount of right-of-use assets and associated lease liabilities recorded upon adoption will be based on the present value of future minimum lease payments, the amount of which will depend on the population of leases in effect at the date of adoption. In addition, First Midwest Bank (the "Bank") entered into a sale-leaseback transaction in 2016 that resulted in a deferred gain. Upon adoption of this guidance, the remaining deferred gain, which is estimated to be approximately $50 million after tax, will be recognized immediately as a cumulative-effect adjustment to equity. For additional discussion of the sale-leaseback transaction, see Note 8 " Premises, Furniture, and Equipment " to the Consolidated Financial Statements in the Company's 2017 10-K. Management is completing its evaluation of the guidance and does not expect the adoption of the guidance will materially impact the Company 's results of operations or liquidity, but anticipates a material increase in assets, liabilities, and equity. Measurement of Credit Losses on Financial Instruments: In June of 2016, the FASB issued guidance that will require entities to present financial assets measured at amortized cost at the net amount expected to be collected, considering an entity's current estimate of all expected credit losses. In addition, credit losses relating to available-for-sale debt securities will be required to be recorded through an allowance for credit losses, with changes in credit loss estimates recognized through current earnings. This guidance is effective for annual and interim periods beginning after December 15, 2019. Early adoption is permitted, but not for periods beginning before December 15, 2018. Management is evaluating the guidance and the impact to the Company 's financial condition, results of operations, or liquidity. Accounting for Goodwill Impairment: In January of 2017, the FASB issued guidance that simplifies the accounting for goodwill impairment for all entities. The new guidance eliminates the requirement to calculate the implied fair value of goodwill using the second step of the quantitative two-step goodwill impairment model prescribed under current accounting guidance. Under the new guidance, if a reporting unit's carrying amount exceeds its fair value, an entity will record an impairment charge based on that difference. This guidance is effective for annual and interim goodwill impairment testing dates beginning after December 15, 2019. Early adoption is permitted for annual and interim goodwill impairment testing dates after January 1, 2017. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Premium Amortization on Purchased Callable Debt Securities: In March of 2017, the FASB issued guidance that shortens the amortization period for the premium on certain purchased callable debt securities to the earliest call date. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Improvements to Nonemployee Share-based Payment Accounting: In June of 2018, the FASB issued guidance that aligns the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Changes to the Disclosure Requirements for Fair Value Measurement: In August of 2018, the FASB issued guidance that eliminates, modifies, and adds to certain fair value measurement disclosure requirements associated with the three-tiered fair value hierarchy. This guidance is effective for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Changes to the Disclosure Requirements for Defined Benefit Plans: In August of 2018, the FASB issued guidance that makes minor changes and clarifications to the disclosure requirements for entities that sponsor defined benefit plans. This guidance is effective for annual and interim periods beginning after December 15, 2020. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract: In August of 2018, the FASB issued guidance to reduce diversity in practice by clarifying when implementation costs are required to be capitalized in a cloud computing arrangement that is a service contract. This guidance is effective for annual and interim periods beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity.

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Securities Available-for-Sale	A summary of the Company's securities portfolio by category and maturity is presented in the following tables. Securities Portfolio (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 49,434 $ — $ (325 ) $ 49,109 $ 46,529 $ — $ (184 ) $ 46,345 U.S. agency securities 143,765 6 (2,517 ) 141,254 157,636 197 (986 ) 156,847 Collateralized mortgage obligations ("CMOs") 1,304,611 103 (46,787 ) 1,257,927 1,113,019 121 (17,954 ) 1,095,186 Other mortgage-backed securities ("MBSs") 462,046 114 (16,495 ) 445,665 373,676 201 (4,334 ) 369,543 Municipal securities 228,048 118 (5,131 ) 223,035 209,558 693 (1,260 ) 208,991 Corporate debt securities 62,888 32 (500 ) 62,420 — — — — Equity securities (1) — — — — 7,408 194 (305 ) 7,297 Total securities available-for-sale $ 2,250,792 $ 373 $ (71,755 ) $ 2,179,410 $ 1,907,826 $ 1,406 $ (25,023 ) $ 1,884,209 Securities Held-to-Maturity Municipal securities $ 12,673 $ — $ (2,158 ) $ 10,515 $ 13,760 $ — $ (1,747 ) $ 12,013 Equity Securities (1) $ 29,046 $ — Trading Securities (1) $ — $ 20,447 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ."
Securities Held-to-Maturity	A summary of the Company's securities portfolio by category and maturity is presented in the following tables. Securities Portfolio (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 49,434 $ — $ (325 ) $ 49,109 $ 46,529 $ — $ (184 ) $ 46,345 U.S. agency securities 143,765 6 (2,517 ) 141,254 157,636 197 (986 ) 156,847 Collateralized mortgage obligations ("CMOs") 1,304,611 103 (46,787 ) 1,257,927 1,113,019 121 (17,954 ) 1,095,186 Other mortgage-backed securities ("MBSs") 462,046 114 (16,495 ) 445,665 373,676 201 (4,334 ) 369,543 Municipal securities 228,048 118 (5,131 ) 223,035 209,558 693 (1,260 ) 208,991 Corporate debt securities 62,888 32 (500 ) 62,420 — — — — Equity securities (1) — — — — 7,408 194 (305 ) 7,297 Total securities available-for-sale $ 2,250,792 $ 373 $ (71,755 ) $ 2,179,410 $ 1,907,826 $ 1,406 $ (25,023 ) $ 1,884,209 Securities Held-to-Maturity Municipal securities $ 12,673 $ — $ (2,158 ) $ 10,515 $ 13,760 $ — $ (1,747 ) $ 12,013 Equity Securities (1) $ 29,046 $ — Trading Securities (1) $ — $ 20,447 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ."
Equity Securities	A summary of the Company's securities portfolio by category and maturity is presented in the following tables. Securities Portfolio (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 49,434 $ — $ (325 ) $ 49,109 $ 46,529 $ — $ (184 ) $ 46,345 U.S. agency securities 143,765 6 (2,517 ) 141,254 157,636 197 (986 ) 156,847 Collateralized mortgage obligations ("CMOs") 1,304,611 103 (46,787 ) 1,257,927 1,113,019 121 (17,954 ) 1,095,186 Other mortgage-backed securities ("MBSs") 462,046 114 (16,495 ) 445,665 373,676 201 (4,334 ) 369,543 Municipal securities 228,048 118 (5,131 ) 223,035 209,558 693 (1,260 ) 208,991 Corporate debt securities 62,888 32 (500 ) 62,420 — — — — Equity securities (1) — — — — 7,408 194 (305 ) 7,297 Total securities available-for-sale $ 2,250,792 $ 373 $ (71,755 ) $ 2,179,410 $ 1,907,826 $ 1,406 $ (25,023 ) $ 1,884,209 Securities Held-to-Maturity Municipal securities $ 12,673 $ — $ (2,158 ) $ 10,515 $ 13,760 $ — $ (1,747 ) $ 12,013 Equity Securities (1) $ 29,046 $ — Trading Securities (1) $ — $ 20,447 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ."
Trading Securities	A summary of the Company's securities portfolio by category and maturity is presented in the following tables. Securities Portfolio (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Value Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 49,434 $ — $ (325 ) $ 49,109 $ 46,529 $ — $ (184 ) $ 46,345 U.S. agency securities 143,765 6 (2,517 ) 141,254 157,636 197 (986 ) 156,847 Collateralized mortgage obligations ("CMOs") 1,304,611 103 (46,787 ) 1,257,927 1,113,019 121 (17,954 ) 1,095,186 Other mortgage-backed securities ("MBSs") 462,046 114 (16,495 ) 445,665 373,676 201 (4,334 ) 369,543 Municipal securities 228,048 118 (5,131 ) 223,035 209,558 693 (1,260 ) 208,991 Corporate debt securities 62,888 32 (500 ) 62,420 — — — — Equity securities (1) — — — — 7,408 194 (305 ) 7,297 Total securities available-for-sale $ 2,250,792 $ 373 $ (71,755 ) $ 2,179,410 $ 1,907,826 $ 1,406 $ (25,023 ) $ 1,884,209 Securities Held-to-Maturity Municipal securities $ 12,673 $ — $ (2,158 ) $ 10,515 $ 13,760 $ — $ (1,747 ) $ 12,013 Equity Securities (1) $ 29,046 $ — Trading Securities (1) $ — $ 20,447 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ."
Remaining Contractual Maturity of Securities	Remaining Contractual Maturity of Securities (Dollar amounts in thousands) As of September 30, 2018 Available-for-Sale Held-to-Maturity Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 113,814 $ 111,859 $ 1,631 $ 1,353 After one year to five years 171,155 168,215 4,915 4,078 After five years to ten years 199,166 195,744 2,176 1,806 After ten years — — 3,951 3,278 Securities that do not have a single contractual maturity date 1,766,657 1,703,592 — — Total $ 2,250,792 $ 2,179,410 $ 12,673 $ 10,515
Securities Available-for-Sale Gains	Securities Available-for-Sale Gains (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Gains on sales of securities: Gross realized gains $ — $ 3,197 $ — $ 3,481 Gross realized losses — — — — Net realized gains on sales of securities — 3,197 — 3,481 Non-cash impairment charges: Other-than-temporary securities impairment ("OTTI") — — — — Net realized gains $ — $ 3,197 $ — $ 3,481
Securities in an Unrealized Loss Position	The following table presents the aggregate amount of unrealized losses and the aggregate related fair values of securities with unrealized losses as of September 30, 2018 and December 31, 2017 . Securities in an Unrealized Loss Position (Dollar amounts in thousands) Less Than 12 Months 12 Months or Longer Total Number of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses As of September 30, 2018 Securities Available-for-Sale U.S. treasury securities 24 $ 38,623 $ 307 $ 10,486 $ 18 $ 49,109 $ 325 U.S. agency securities 75 81,753 1,398 54,161 1,119 135,914 2,517 CMOs 260 610,183 15,445 602,362 31,342 1,212,545 46,787 MBSs 119 215,463 5,396 222,989 11,099 438,452 16,495 Municipal securities 501 140,916 2,762 55,975 2,369 196,891 5,131 Corporate debt securities 8 36,621 500 — — 36,621 500 Total 987 $ 1,123,559 $ 25,808 $ 945,973 $ 45,947 $ 2,069,532 $ 71,755 Securities Held-to-Maturity Municipal securities 8 $ — $ — $ 10,515 $ 2,158 $ 10,515 $ 2,158 As of December 31, 2017 Securities Available-for-Sale U.S. treasury securities 20 $ 19,918 $ 87 $ 26,427 $ 97 $ 46,345 $ 184 U.S. agency securities 72 66,899 300 58,021 686 124,920 986 CMOs 211 365,131 3,265 633,227 14,689 998,358 17,954 MBSs 86 126,136 902 210,017 3,432 336,153 4,334 Municipal securities 265 35,500 479 81,360 781 116,860 1,260 Equity securities (1) 2 391 214 6,386 91 6,777 305 Total 656 $ 613,975 $ 5,247 $ 1,015,438 $ 19,776 $ 1,629,413 $ 25,023 Securities Held-to-Maturity Municipal securities 8 $ — $ — $ 12,013 $ 1,747 $ 12,013 $ 1,747 (1) As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2 , " Recent Accounting Pronouncements ."

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2018
Loans and Leases Receivable Disclosure [Abstract]
Composition Of Loan Portfolio	The following table presents the Company 's loans held-for-investment by class. Loan Portfolio (Dollar amounts in thousands) As of September 30, December 31, Commercial and industrial $ 3,994,142 $ 3,529,914 Agricultural 432,220 430,886 Commercial real estate: Office, retail, and industrial 1,782,757 1,979,820 Multi-family 698,611 675,463 Construction 632,779 539,820 Other commercial real estate 1,348,831 1,358,515 Total commercial real estate 4,462,978 4,553,618 Total corporate loans 8,889,340 8,514,418 Home equity 853,887 827,055 1-4 family mortgages 888,797 774,357 Installment 418,524 321,982 Total consumer loans 2,161,208 1,923,394 Total loans $ 11,050,548 $ 10,437,812 Deferred loan fees included in total loans $ 5,887 $ 4,986 Overdrawn demand deposits included in total loans 8,239 8,587
Schedule Of Loans Sold	The following table presents loan sales for the quarters and nine months ended September 30, 2018 and 2017 . Loan Sales (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Corporate loan sales Proceeds from sales $ 2,868 $ 11,833 $ 15,180 $ 46,770 Less book value of loans sold 2,827 11,512 14,811 45,752 Net gains on corporate loan sales (1) 41 321 369 1,018 1-4 family mortgage loan sales Proceeds from sales $ 62,576 $ 73,889 $ 193,476 $ 190,544 Less book value of loans sold 61,276 72,149 189,370 186,208 Net gains on 1-4 family mortgage loan sales (2) 1,300 1,740 4,106 4,336 Total net gains on loan sales $ 1,341 $ 2,061 $ 4,475 $ 5,354 (1) Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Condensed Consolidated Statements of Income. (2) Net gains on 1-4 family mortgage loan sales are included in mortgage banking income in the Condensed Consolidated Statements of Income.

Acquired and Covered Loans (Tab

Acquired and Covered Loans (Tables)	9 Months Ended
	Sep. 30, 2018
Transfers and Servicing [Abstract]
Acquired Loans	The following table presents the carrying amount of acquired and covered PCI and non-PCI loans as of September 30, 2018 and December 31, 2017 . Acquired and Covered Loans (1) (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 PCI Non-PCI Total PCI Non-PCI Total Acquired loans $ 98,923 $ 1,121,092 $ 1,220,015 $ 130,694 $ 1,512,664 $ 1,643,358 Covered loans 6,021 7,632 13,653 6,759 11,789 18,548 Total acquired and covered loans $ 104,944 $ 1,128,724 $ 1,233,668 $ 137,453 $ 1,524,453 $ 1,661,906 (1) Included in loans in the Consolidated Statements of Condition.
FDIC Indemnification Asset Roll Forward	Rollforwards of the carrying value of the FDIC indemnification asset for the quarters and nine months ended September 30, 2018 and 2017 are presented in the following table. Changes in the FDIC Indemnification Asset (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 2,710 $ 3,918 $ 3,314 $ 4,522 Amortization (302 ) (302 ) (906 ) (906 ) Change in expected reimbursements from the FDIC for changes in expected credit losses (336 ) (123 ) (161 ) (653 ) Net payments to the FDIC 334 123 159 653 Ending balance $ 2,406 $ 3,616 $ 2,406 $ 3,616
Schedule Of Changes In Accretable Yield For Purchased Credit Impaired Loans	Changes in the accretable yield for acquired and covered PCI loans were as follows. Changes in Accretable Yield (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Beginning balances $ 39,008 $ 39,870 $ 32,957 $ 19,385 Additions — — — 27,316 Accretion (3,008 ) (4,263 ) (9,548 ) (12,106 ) Other (1) 2,672 478 15,263 1,490 Ending balance $ 38,672 $ 36,085 $ 38,672 $ 36,085 (1) Increases represent a rise in the expected future cash flows to be collected over the remaining estimated life of the underlying portfolio, while decreases result from the resolution of certain loans occurring earlier than anticipated.

Past Due Loans, Allowance For_2

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS (Tables)	9 Months Ended
	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]
Past Due Financing Receivables	The following table presents an aging analysis of the Company 's past due loans as of September 30, 2018 and December 31, 2017 . The aging is determined without regard to accrual status. The table also presents non-performing loans, consisting of non-accrual loans (the majority of which are past due) and loans 90 days or more past due and still accruing interest, as of each balance sheet date. Aging Analysis of Past Due Loans and Non-performing Loans by Class (Dollar amounts in thousands) Aging Analysis (Accruing and Non-accrual) Non-performing Loans Current (1) 30-89 Days Past Due 90 Days or More Past Due Total Past Due Total Loans Non- accrual (2) 90 Days or More Past Due, Still Accruing Interest As of September 30, 2018 Commercial and industrial $ 3,966,088 $ 15,087 $ 12,967 $ 28,054 $ 3,994,142 $ 37,981 $ 1,096 Agricultural 427,702 2,156 2,362 4,518 432,220 2,104 316 Commercial real estate: Office, retail, and industrial 1,767,366 9,640 5,751 15,391 1,782,757 6,685 490 Multi-family 691,698 3,729 3,184 6,913 698,611 3,184 — Construction 628,976 3,595 208 3,803 632,779 208 — Other commercial real estate 1,339,926 5,755 3,150 8,905 1,348,831 4,578 288 Total commercial real estate 4,427,966 22,719 12,293 35,012 4,462,978 14,655 778 Total corporate loans 8,821,756 39,962 27,622 67,584 8,889,340 54,740 2,190 Home equity 848,843 2,995 2,049 5,044 853,887 5,739 9 1-4 family mortgages 885,556 1,287 1,954 3,241 888,797 4,287 41 Installment 414,078 3,737 709 4,446 418,524 — 709 Total consumer loans 2,148,477 8,019 4,712 12,731 2,161,208 10,026 759 Total loans $ 10,970,233 $ 47,981 $ 32,334 $ 80,315 $ 11,050,548 $ 64,766 $ 2,949 As of December 31, 2017 Commercial and industrial $ 3,490,783 $ 34,620 $ 4,511 $ 39,131 $ 3,529,914 $ 40,580 $ 1,830 Agricultural 430,221 280 385 665 430,886 219 177 Commercial real estate: Office, retail, and industrial 1,970,564 3,156 6,100 9,256 1,979,820 11,560 345 Multi-family 672,098 3,117 248 3,365 675,463 377 20 Construction 539,043 198 579 777 539,820 209 371 Other commercial real estate 1,353,263 2,545 2,707 5,252 1,358,515 3,621 317 Total commercial real estate 4,534,968 9,016 9,634 18,650 4,553,618 15,767 1,053 Total corporate loans 8,455,972 43,916 14,530 58,446 8,514,418 56,566 3,060 Home equity 820,099 4,102 2,854 6,956 827,055 5,946 98 1-4 family mortgages 770,120 2,145 2,092 4,237 774,357 4,412 — Installment 319,178 2,407 397 2,804 321,982 — 397 Total consumer loans 1,909,397 8,654 5,343 13,997 1,923,394 10,358 495 Total loans $ 10,365,369 $ 52,570 $ 19,873 $ 72,443 $ 10,437,812 $ 66,924 $ 3,555 (1) PCI loans with an accretable yield are considered current. (2) Includes PCI loans of $688,000 and $763,000 as of September 30, 2018 and December 31, 2017 , respectively, which no longer have an accretable yield as estimates of expected future cash flows have decreased since the acquisition due to credit deterioration.
Allowance for Credit Losses on Financing Receivables	A rollforward of the allowance for credit losses by portfolio segment for the quarters and nine months ended September 30, 2018 and 2017 is presented in the table below. Allowance for Credit Losses by Portfolio Segment (Dollar amounts in thousands) Commercial, Industrial, and Agricultural Office, Retail, and Industrial Multi- family Construction Other Commercial Real Estate Consumer Reserve for Unfunded Commitments Total Allowance for Credit Losses Quarter ended September 30, 2018 Beginning balance $ 60,043 $ 9,062 $ 2,175 $ 2,124 $ 4,631 $ 18,656 $ 1,000 $ 97,691 Charge-offs (6,277 ) (759 ) (1 ) (1 ) (177 ) (2,049 ) — (9,264 ) Recoveries 416 163 — 5 154 512 — 1,250 Net charge-offs (5,861 ) (596 ) (1 ) 4 (23 ) (1,537 ) — (8,014 ) Provision for loan losses and other 6,776 15 200 116 740 3,401 — 11,248 Ending balance $ 60,958 $ 8,481 $ 2,374 $ 2,244 $ 5,348 $ 20,520 $ 1,000 $ 100,925 Quarter ended September 30, 2017 Beginning balance $ 46,271 $ 15,008 $ 2,919 $ 4,094 $ 7,479 $ 16,600 $ 1,000 $ 93,371 Charge-offs (8,935 ) (14 ) — 6 (6 ) (1,617 ) — (10,566 ) Recoveries 698 1,825 2 19 25 331 — 2,900 Net charge-offs (8,237 ) 1,811 2 25 19 (1,286 ) — (7,666 ) Provision for loan losses and other 13,994 (5,129 ) (296 ) 161 (257 ) 1,636 — 10,109 Ending balance $ 52,028 $ 11,690 $ 2,625 $ 4,280 $ 7,241 $ 16,950 $ 1,000 $ 95,814 Nine months ended September 30, 2018 Beginning balance $ 55,791 $ 10,996 $ 2,534 $ 3,481 $ 6,381 $ 16,546 $ 1,000 $ 96,729 Charge-offs (29,609 ) (1,525 ) (5 ) (1 ) (247 ) (6,271 ) — (37,658 ) Recoveries 1,707 286 — 26 552 1,240 — 3,811 Net charge-offs (27,902 ) (1,239 ) (5 ) 25 305 (5,031 ) — (33,847 ) Provision for loan losses and other 33,069 (1,276 ) (155 ) (1,262 ) (1,338 ) 9,005 — 38,043 Ending balance $ 60,958 $ 8,481 $ 2,374 $ 2,244 $ 5,348 $ 20,520 $ 1,000 $ 100,925 Nine months ended September 30, 2017 Beginning balance $ 40,709 $ 17,595 $ 3,261 $ 3,444 $ 7,739 $ 13,335 $ 1,000 $ 87,083 Charge-offs (15,966 ) (141 ) — (38 ) (721 ) (4,837 ) — (21,703 ) Recoveries 2,764 2,808 36 258 205 1,097 — 7,168 Net charge-offs (13,202 ) 2,667 36 220 (516 ) (3,740 ) — (14,535 ) Provision for loan losses and other 24,521 (8,572 ) (672 ) 616 18 7,355 — 23,266 Ending balance $ 52,028 $ 11,690 $ 2,625 $ 4,280 $ 7,241 $ 16,950 $ 1,000 $ 95,814
Schedule of Loans and The Related Allowance For Credit Losses	The table below provides a breakdown of loans and the related allowance for credit losses by portfolio segment as of September 30, 2018 and December 31, 2017 . Loans and Related Allowance for Credit Losses by Portfolio Segment (Dollar amounts in thousands) Loans Allowance for Credit Losses Individually Evaluated for Impairment Collectively Evaluated for Impairment PCI Total Individually Evaluated for Impairment Collectively Evaluated for Impairment PCI Total As of September 30, 2018 Commercial, industrial, and agricultural $ 37,309 $ 4,385,067 $ 3,986 $ 4,426,362 $ 6,659 $ 53,919 $ 380 $ 60,958 Commercial real estate: Office, retail, and industrial 5,639 1,765,584 11,534 1,782,757 1,223 6,049 1,209 8,481 Multi-family 3,573 684,275 10,763 698,611 — 2,134 240 2,374 Construction — 629,427 3,352 632,779 — 2,089 155 2,244 Other commercial real estate 2,496 1,290,122 56,213 1,348,831 22 4,113 1,213 5,348 Total commercial real estate 11,708 4,369,408 81,862 4,462,978 1,245 14,385 2,817 18,447 Total corporate loans 49,017 8,754,475 85,848 8,889,340 7,904 68,304 3,197 79,405 Consumer — 2,142,112 19,096 2,161,208 — 19,003 1,517 20,520 Reserve for unfunded commitments — — — — — 1,000 — 1,000 Total loans $ 49,017 $ 10,896,587 $ 104,944 $ 11,050,548 $ 7,904 $ 88,307 $ 4,714 $ 100,925 As of December 31, 2017 Commercial, industrial, and agricultural $ 38,718 $ 3,909,380 $ 12,702 $ 3,960,800 $ 10,074 $ 45,293 $ 424 $ 55,791 Commercial real estate: Office, retail, and industrial 10,810 1,954,435 14,575 1,979,820 — 9,333 1,663 10,996 Multi-family 621 660,771 14,071 675,463 — 2,436 98 2,534 Construction — 530,977 8,843 539,820 — 3,331 150 3,481 Other commercial real estate 1,468 1,291,723 65,324 1,358,515 — 5,415 966 6,381 Total commercial real estate 12,899 4,437,906 102,813 4,553,618 — 20,515 2,877 23,392 Total corporate loans 51,617 8,347,286 115,515 8,514,418 10,074 65,808 3,301 79,183 Consumer — 1,901,456 21,938 1,923,394 — 15,533 1,013 16,546 Reserve for unfunded commitments — — — — — 1,000 — 1,000 Total loans $ 51,617 $ 10,248,742 $ 137,453 $ 10,437,812 $ 10,074 $ 82,341 $ 4,314 $ 96,729
Impaired Financing Receivables	The following table presents the average recorded investment and interest income recognized on impaired loans by class for the quarters and nine months ended September 30, 2018 and 2017 . PCI loans are excluded from this disclosure. Average Recorded Investment and Interest Income Recognized on Impaired Loans by Class (Dollar amounts in thousands) Quarters Ended September 30, 2018 2017 Average Interest Income Recognized (1) Average Interest Income Recognized (1) Commercial and industrial $ 28,082 $ 123 $ 44,682 $ 368 Agricultural 2,372 — 140 — Commercial real estate: Office, retail, and industrial 6,641 105 12,496 — Multi-family 3,757 11 396 — Construction — — — — Other commercial real estate 2,831 68 1,415 — Total commercial real estate 13,229 184 14,307 — Total impaired loans $ 43,683 $ 307 $ 59,129 $ 368 Nine Months Ended September 30, 2018 2017 Average Interest (1) Average Interest (1) Commercial and industrial $ 34,440 $ 159 $ 32,765 $ 924 Agricultural 2,153 25 348 — Commercial real estate: Office, retail, and industrial 8,867 873 13,680 262 Multi-family 2,132 66 396 28 Construction — — 9 136 Other commercial real estate 2,338 181 1,652 20 Total commercial real estate 13,337 1,120 15,737 446 Total impaired loans $ 49,930 $ 1,304 $ 48,850 $ 1,370 (1) Recorded using the cash basis of accounting. The following table presents loans individually evaluated for impairment by class of loan as of September 30, 2018 and December 31, 2017 . PCI loans are excluded from this disclosure. Impaired Loans Individually Evaluated by Class (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Recorded Investment In Recorded Investment In Loans with No Specific Reserve Loans with a Specific Reserve Unpaid Principal Balance Specific Reserve Loans with No Specific Reserve Loans with a Specific Reserve Unpaid Principal Balance Specific Reserve Commercial and industrial $ 7,534 $ 27,934 $ 53,533 $ 6,542 $ 4,234 $ 34,484 $ 53,192 $ 10,074 Agricultural 269 1,572 4,250 117 — — — — Commercial real estate: Office, retail, and industrial 1,636 4,003 6,372 1,223 7,154 3,656 14,246 — Multi-family 3,573 — 3,573 — 621 — 621 — Construction — — — — — — — — Other commercial real estate 1,632 864 2,548 22 1,468 — 1,566 — Total commercial real estate 6,841 4,867 12,493 1,245 9,243 3,656 16,433 — Total impaired loans individually evaluated for impairment $ 14,644 $ 34,373 $ 70,276 $ 7,904 $ 13,477 $ 38,140 $ 69,625 $ 10,074
Financing Receivable Credit Quality Indicators	The following tables present credit quality indicators by class for corporate and consumer loans, as of September 30, 2018 and December 31, 2017 . Corporate Credit Quality Indicators by Class (Dollar amounts in thousands) Pass Special Mention (1)(4) Substandard (2)(4) Non-accrual (3) Total As of September 30, 2018 Commercial and industrial $ 3,797,606 $ 134,184 $ 24,371 $ 37,981 $ 3,994,142 Agricultural 411,559 7,591 10,966 2,104 432,220 Commercial real estate: Office, retail, and industrial 1,721,711 19,972 34,389 6,685 1,782,757 Multi-family 683,199 10,139 2,089 3,184 698,611 Construction 601,942 23,477 7,152 208 632,779 Other commercial real estate 1,277,662 48,845 17,746 4,578 1,348,831 Total commercial real estate 4,284,514 102,433 61,376 14,655 4,462,978 Total corporate loans $ 8,493,679 $ 244,208 $ 96,713 $ 54,740 $ 8,889,340 As of December 31, 2017 Commercial and industrial $ 3,388,133 $ 70,863 $ 30,338 $ 40,580 $ 3,529,914 Agricultural 413,946 10,989 5,732 219 430,886 Commercial real estate: Office, retail, and industrial 1,903,737 25,546 38,977 11,560 1,979,820 Multi-family 665,496 7,395 2,195 377 675,463 Construction 521,911 10,184 7,516 209 539,820 Other commercial real estate 1,304,337 29,624 20,933 3,621 1,358,515 Total commercial real estate 4,395,481 72,749 69,621 15,767 4,553,618 Total corporate loans $ 8,197,560 $ 154,601 $ 105,691 $ 56,566 $ 8,514,418 (1) Loans categorized as special mention exhibit potential weaknesses that require the close attention of management since these potential weaknesses may result in the deterioration of repayment prospects in the future. (2) Loans categorized as substandard exhibit well-defined weaknesses that may jeopardize the liquidation of the debt. These loans continue to accrue interest because they are well-secured and collection of principal and interest is expected within a reasonable time. (3) Loans categorized as non-accrual exhibit well-defined weaknesses that may jeopardize the liquidation of the debt or result in a loss if the deficiencies are not corrected. (4) Total special mention and substandard loans includes accruing TDR s of $639,000 as of September 30, 2018 and $657,000 as of December 31, 2017 . Consumer Credit Quality Indicators by Class (Dollar amounts in thousands) Performing Non-accrual Total As of September 30, 2018 Home equity $ 848,148 $ 5,739 $ 853,887 1-4 family mortgages 884,510 4,287 888,797 Installment 418,524 — 418,524 Total consumer loans $ 2,151,182 $ 10,026 $ 2,161,208 As of December 31, 2017 Home equity $ 821,109 $ 5,946 $ 827,055 1-4 family mortgages 769,945 4,412 774,357 Installment 321,982 — 321,982 Total consumer loans $ 1,913,036 $ 10,358 $ 1,923,394
Troubled Debt Restructuring Activity Rollforward	There were no material restructurings during the quarter and nine months ended September 30, 2018 . The following table presents a summary of loans that were restructured during the quarter and nine months ended September 30, 2017. Loans Restructured During the Period (Dollar amounts in thousands) Number of Loans Pre- Modification Recorded Investment Funds Disbursed Interest and Escrow Capitalized Charge-offs Post- Modification Recorded Investment Quarter ended September 30, 2017 Commercial and industrial 10 $ 25,811 $ 196 $ — $ 1,736 $ 24,271 Office, retail, and industrial 2 3,656 — — — 3,656 Total TDRs restructured during the period 12 $ 29,467 $ 196 $ — $ 1,736 $ 27,927 Nine months ended September 30, 2017 Commercial and industrial 12 $ 26,733 $ 196 $ — $ 1,736 $ 25,193 Office, retail, and industrial 2 3,656 — — — 3,656 Total TDRs restructured during the period 14 $ 30,389 $ 196 $ — $ 1,736 $ 28,849 The table below presents TDR s by class as of September 30, 2018 and December 31, 2017 . See Note 1, "Summary of Significant Accounting Policies," for the accounting policy for TDR s. TDR s by Class (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Accruing Non-accrual (1) Total Accruing Non-accrual (1) Total Commercial and industrial $ 250 $ 5,603 $ 5,853 $ 264 $ 18,959 $ 19,223 Agricultural — — — — — — Commercial real estate: Office, retail, and industrial — — — — 4,236 4,236 Multi-family 563 — 563 574 149 723 Construction — — — — — — Other commercial real estate 184 — 184 192 — 192 Total commercial real estate 747 — 747 766 4,385 5,151 Total corporate loans 997 5,603 6,600 1,030 23,344 24,374 Home equity 83 352 435 86 738 824 1-4 family mortgages 661 410 1,071 680 451 1,131 Installment — — — — — — Total consumer loans 744 762 1,506 766 1,189 1,955 Total loans $ 1,741 $ 6,365 $ 8,106 $ 1,796 $ 24,533 $ 26,329 (1) These TDR s are included in non-accrual loans in the preceding tables. A rollforward of the carrying value of TDR s for the quarters and nine months ended September 30, 2018 and 2017 is presented in the following table. TDR Rollforward (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Accruing Beginning balance $ 1,760 $ 2,029 $ 1,796 $ 2,291 Additions — 14,897 — 15,819 Net payments (19 ) (1,798 ) (55 ) (1,905 ) Net transfers to non-accrual — (13,315 ) — (14,392 ) Ending balance 1,741 1,813 1,741 1,813 Non-accrual Beginning balance 8,238 3,036 24,533 6,297 Additions — 14,570 355 14,570 Net payments (1,620 ) (127 ) (14,598 ) (4,352 ) Charge-offs (253 ) (2,132 ) (3,925 ) (2,245 ) Net transfers from accruing — 13,315 — 14,392 Ending balance 6,365 28,662 6,365 28,662 Total TDRs $ 8,106 $ 30,475 $ 8,106 $ 30,475

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The table below displays the calculation of basic and diluted earnings per common share (" EPS "). Basic and Diluted EPS (Amounts in thousands, except per share data) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Net income $ 53,352 $ 38,235 $ 116,462 $ 96,040 Net income applicable to non-vested restricted shares (441 ) (340 ) (992 ) (910 ) Net income applicable to common shares $ 52,911 $ 37,895 $ 115,470 $ 95,130 Weighted-average common shares outstanding: Weighted-average common shares outstanding (basic) 102,178 101,752 102,087 101,307 Dilutive effect of common stock equivalents — 20 5 20 Weighted-average diluted common shares outstanding 102,178 101,772 102,092 101,327 Basic EPS $ 0.52 $ 0.37 $ 1.13 $ 0.94 Diluted EPS $ 0.52 $ 0.37 $ 1.13 $ 0.94 Anti-dilutive shares not included in the computation of diluted EPS (1) — 190 36 242 (1) This amount represents outstanding stock options for which the exercise price is greater than the average market price of the Company's common stock. The final outstanding stock options were exercised during the first quarter of 2018.

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense	The following table presents income tax expense and the effective income tax rate for the quarters and nine months ended September 30, 2018 and 2017 . Income Tax Expense (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Income before income tax expense $ 59,968 $ 55,942 $ 142,605 $ 144,068 Income tax expense: Federal income tax expense $ 2,634 $ 16,355 $ 17,403 $ 41,408 State income tax expense 3,982 1,352 8,740 6,620 Total income tax expense $ 6,616 $ 17,707 $ 26,143 $ 48,028 Effective income tax rate 11.0 % 31.7 % 18.3 % 33.3 %

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Derivatives	Fair Value Hedges (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Gross notional amount outstanding $ 5,083 $ 5,458 Derivative liability fair value in other liabilities (9 ) (101 ) Weighted-average interest rate received 4.11 % 3.38 % Weighted-average interest rate paid 5.96 % 5.96 % Weighted-average maturity (in years) 0.10 0.84 Fair value of derivative (1) $ 15 $ 110 (1) This amount represents the fair value if credit risk related contingent features were triggered. Cash Flow Hedges (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Gross notional amount outstanding $ 2,170,000 $ 1,960,000 Derivative asset fair value in other assets (1) 6,009 3,989 Derivative liability fair value in other liabilities (1) (19,197 ) (10,219 ) Weighted-average interest rate received 2.01 % 1.58 % Weighted-average interest rate paid 2.03 % 1.61 % Weighted-average maturity (in years) 1.76 2.25 (1) Certain cash flow hedges are transacted through a clearinghouse ("centrally cleared") and their change in fair value is settled by the counterparties to the transaction, which results in no fair value. The following table presents the impact of derivative instruments on net interest income for the quarters and nine months ended September 30, 2018 and 2017 . Hedge Income (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Fair Value Hedges Interest rate swaps in interest income $ (24 ) $ (39 ) $ (83 ) $ (129 ) Cash Flow Hedges Interest rate swaps in interest income 857 946 1,504 4,333 Interest rate swaps in interest expense (978 ) (919 ) (2,087 ) (3,142 ) Total cash flow hedges (121 ) 27 (583 ) 1,191 Total net (losses) gains on hedges $ (145 ) $ (12 ) $ (666 ) $ 1,062
Schedule of Derivative Instruments	Other Derivative Instruments (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Gross notional amount outstanding $ 3,134,222 $ 2,665,358 Derivative asset fair value in other assets (1) 31,044 17,079 Derivative liability fair value in other liabilities (1) (33,832 ) (14,930 ) Fair value of derivative (2) 33,974 15,059 (1) Certain other derivative instruments are centrally cleared and their change in fair value is settled by the counterparties to the transaction, which results in no fair value. (2) This amount represents the fair value if credit risk related contingent features were triggered.
Cash Flow Hedge Accounting on AOCI	The following table presents the impact of derivative instruments on comprehensive income and the reclassification of gains (losses) from accumulated other comprehensive loss to net interest income for the quarters and nine months ended September 30, 2018 and 2017 . Cash Flow Hedge Accounting on AOCI (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Gains (losses) recognized in other comprehensive income Interest rate swaps in interest income $ 2,578 $ 113 $ 13,151 $ 5,465 Interest rate swaps in interest expense (1,577 ) (416 ) (11,620 ) (3,807 ) Reclassification of gains (losses) included in net income Interest rate swaps in interest income $ 857 $ 946 $ 1,504 $ 4,333 Interest rate swaps in interest expense (978 ) (919 ) (2,087 ) (3,142 )
Offsetting Assets	The following table presents the fair value of the Company's derivatives and offsetting positions as of September 30, 2018 and December 31, 2017 . Fair Value of Offsetting Derivatives (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Assets Liabilities Assets Liabilities Gross amounts recognized $ 37,053 $ 53,038 $ 21,068 $ 25,250 Less: amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition (1) 37,053 53,038 21,068 25,250 Gross amounts not offset in the Consolidated Statements of Financial Condition: Offsetting derivative positions (15,177 ) (15,177 ) (16,880 ) (16,880 ) Cash collateral pledged (20,440 ) (3,440 ) — (8,370 ) Net credit exposure $ 1,436 $ 34,421 $ 4,188 $ — (1) Included in other assets or other liabilities in the Consolidated Statements of Financial Condition.
Offsetting Liabilities	The following table presents the fair value of the Company's derivatives and offsetting positions as of September 30, 2018 and December 31, 2017 . Fair Value of Offsetting Derivatives (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Assets Liabilities Assets Liabilities Gross amounts recognized $ 37,053 $ 53,038 $ 21,068 $ 25,250 Less: amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition (1) 37,053 53,038 21,068 25,250 Gross amounts not offset in the Consolidated Statements of Financial Condition: Offsetting derivative positions (15,177 ) (15,177 ) (16,880 ) (16,880 ) Cash collateral pledged (20,440 ) (3,440 ) — (8,370 ) Net credit exposure $ 1,436 $ 34,421 $ 4,188 $ — (1) Included in other assets or other liabilities in the Consolidated Statements of Financial Condition.

Commitments, Guarantees, and _2

Commitments, Guarantees, and Contingent Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments Disclosure	Contractual or Notional Amounts of Financial Instruments (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Commitments to extend credit: Commercial, industrial, and agricultural $ 1,710,789 $ 1,729,426 Commercial real estate 327,279 377,551 Home equity 547,943 514,973 Other commitments (1) 240,786 244,222 Total commitments to extend credit $ 2,826,797 $ 2,866,172 Letters of credit $ 112,225 $ 128,801 (1) Other commitments includes installment and overdraft protection program commitments.

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis	The following table provides the fair value for assets and liabilities required to be measured at fair value on a recurring basis in the Consolidated Statements of Financial Condition by level in the fair value hierarchy. Recurring Fair Value Measurements (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets Trading securities: Money market funds $ — $ — $ — $ 1,685 $ — $ — Mutual funds — — — 18,762 — — Total trading securities (1) — — — 20,447 — — Equity securities (1) 22,078 6,968 — — — — Securities available-for-sale (1) U.S. treasury securities 49,109 — — 46,345 — — U.S. agency securities — 141,254 — — 156,847 — CMOs — 1,257,927 — — 1,095,186 — MBSs — 445,665 — — 369,543 — Municipal securities — 223,035 — — 208,991 — Corporate debt securities — 62,420 — — — — Equity securities — — — — 7,297 — Total securities available-for-sale 49,109 2,130,301 — 46,345 1,837,864 — Mortgage servicing rights ("MSRs") (2) — — 6,817 — — 5,894 Derivative assets (2) — 37,053 — — 21,068 — Liabilities Derivative liabilities (3) $ — $ 53,038 $ — $ — $ 25,250 $ — (1) As a result of recently adopted accounting guidance, equity securities are no longer presented within trading securities or securities available-for-sale for the prior period and are now presented within equity securities for the current period. For further discussion of this guidance, see Note 2 of "Notes to the Condensed Consolidated Financial Statements" in Item 1 of this Form 10-Q. (2) Included in other assets in the Consolidated Statements of Financial Condition. (3) Included in other liabilities in the Consolidated Statements of Financial Condition.
Significant Unobservable Inputs Used in the Valuation of MSRs	The following table presents the ranges of significant, unobservable inputs used by the Company to determine the fair value of MSR s as of September 30, 2018 and December 31, 2017 . Significant Unobservable Inputs Used in the Valuation of MSR s As of September 30, 2018 December 31, 2017 Prepayment speed 6.6 % - 13.1% 4.2 % - 13.1% Maturity (months) 2 - 106 6 - 92 Discount rate 9.5 % - 12.0% 9.5 % - 12.0%
Schedule of Servicing Assets at Fair Value	A rollforward of the carrying value of MSR s for the quarters and nine months ended September 30, 2018 and 2017 is presented in the following table. Carrying Value of MSR s (Dollar amounts in thousands) Quarters Ended Nine Months Ended 2018 2017 2018 2017 Beginning balance $ 6,671 $ 5,925 $ 5,894 $ 6,120 New MSRs 324 161 893 522 Total gains (losses) included in earnings (1) : Changes in valuation inputs and assumptions 65 (121 ) 627 (209 ) Other changes in fair value (2) (243 ) (199 ) (597 ) (667 ) Ending balance $ 6,817 $ 5,766 $ 6,817 $ 5,766 Contractual servicing fees earned (1) $ 375 $ 379 $ 1,122 $ 1,158 (1) Included in mortgage banking income in the Condensed Consolidated Statements of Income and related to assets held as of September 30, 2018 and 2017 . (2) Primarily represents changes in expected future cash flows due to payoffs and paydowns.
Fair Value Measurements, Nonrecurring	The following table provides the fair value for each class of assets and liabilities required to be measured at fair value on a non-recurring basis in the Consolidated Statements of Financial Condition by level in the fair value hierarchy. Non-Recurring Fair Value Measurements (Dollar amounts in thousands) As of September 30, 2018 As of December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Collateral-dependent impaired loans (1) $ — $ — $ 28,077 $ — $ — $ 33,240 OREO (2) — — 7,075 — — 12,340 Loans held-for-sale (3) — — 6,020 — — 21,098 Assets held-for-sale (4) — — 4,659 — — 2,208 (1) Includes impaired loans with charge-offs and impaired loans with a specific reserve during the periods presented. (2) Includes OREO with fair value adjustments subsequent to initial transfer that occurred during the periods presented. (3) Included in other assets in the Consolidated Statements of Financial Condition. (4) Included in premises, furniture, and equipment in the Consolidated Statements of Financial Condition.
Fair Value, by Balance Sheet Grouping	For certain financial instruments that are not required to be measured at fair value in the Consolidated Statements of Financial Condition, the Company must disclose the estimated fair values and the level within the fair value hierarchy as shown in the following table. Fair Value Measurements of Other Financial Instruments (Dollar amounts in thousands) As of September 30, 2018 December 31, 2017 Fair Value Hierarchy Level Carrying Amount Fair Value Carrying Amount Fair Value Assets Cash and due from banks 1 $ 185,239 $ 185,239 $ 192,800 $ 192,800 Interest-bearing deposits in other banks 2 111,360 111,360 153,770 153,770 Securities held-to-maturity 2 12,673 10,515 13,760 12,013 FHLB and FRB stock 2 87,728 87,728 69,708 69,708 Loans 3 10,953,029 10,587,311 10,345,397 10,059,992 Investment in BOLI 3 284,074 284,074 279,900 279,900 Accrued interest receivable 3 51,856 51,856 45,261 45,261 Other interest-earning assets 3 33 33 228 228 Liabilities Deposits 2 $ 11,527,114 $ 11,505,442 $ 11,053,325 $ 11,038,819 Borrowed funds 2 1,073,546 1,073,546 714,884 714,884 Senior and subordinated debt 2 195,595 209,917 195,170 208,666 Accrued interest payable 2 6,406 6,406 4,704 4,704

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			$ 96,477	$ 97,190	$ 305,475	$ 313,583
Non-cash transfer of equity securities previously classified as trading securities and securities available-for-sale					29,000
Reclassification of tax effects from AOCI to retained earnings		$ 6,800
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated sale-leaseback deferred gain, net of tax	50
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			4,200		11,900
Difference between Revenue Guidance in Effect before and after Topic 606 | Card-based | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			1,900		5,500
Difference between Revenue Guidance in Effect before and after Topic 606 | Merchant servicing | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Noninterest Expense			$ 2,300		$ 6,400

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 12, 2018	Jan. 06, 2017	Feb. 28, 2017
Standard Bancshares, Inc.
Business Acquisition [Line Items]
Fixed exchange ratio (in shares)		0.4350
Consideration transferred		$ 580.7
Common stock, shares issued (in shares)		21,057,085
Cash paid		$ 47.1
Goodwill		$ 345.3
Premier Asset Management LLC
Business Acquisition [Line Items]
Assets under management acquired			$ 550
Standard Bancshares, Inc.
Business Acquisition [Line Items]
Share price (in Dollars per share)		$ 11.02
First Midwest Bancorp, Inc
Business Acquisition [Line Items]
Share price (in Dollars per share)		$ 25.34
Subsequent Event | Northern States Financial Corporation
Business Acquisition [Line Items]
Total assets	$ 550
Total deposits	465
Total loans	$ 305
Fixed exchange ratio (in shares)	0.0363
Consideration transferred	$ 83
Common stock, shares issued (in shares)	3,300,000

Securities - Securities Portfol

Securities - Securities Portfolio (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Equity securities		$ 29,046	$ 0
Trading securities		0	20,447	[1]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		2,250,792
Amortized Cost			1,907,826
Gross Unrealized Gains		373
Gross Unrealized Gains			1,406
Gross Unrealized Losses		(71,755)
Gross Unrealized Losses			(25,023)
Fair Value		2,179,410
Fair Value			1,884,209
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		12,673	13,760
Fair Value		10,515
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		49,434
Amortized Cost			46,529
Gross Unrealized Gains		0
Gross Unrealized Gains			0
Gross Unrealized Losses		(325)
Gross Unrealized Losses			(184)
Fair Value		49,109
Fair Value			46,345
U.S. agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		143,765
Amortized Cost			157,636
Gross Unrealized Gains		6
Gross Unrealized Gains			197
Gross Unrealized Losses		(2,517)
Gross Unrealized Losses			(986)
Fair Value		141,254
Fair Value			156,847
Collateralized mortgage obligations (CMOs)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		1,304,611
Amortized Cost			1,113,019
Gross Unrealized Gains		103
Gross Unrealized Gains			121
Gross Unrealized Losses		(46,787)
Gross Unrealized Losses			(17,954)
Fair Value		1,257,927
Fair Value			1,095,186
Other mortgage-backed securities (MBSs)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		462,046
Amortized Cost			373,676
Gross Unrealized Gains		114
Gross Unrealized Gains			201
Gross Unrealized Losses		(16,495)
Gross Unrealized Losses			(4,334)
Fair Value		445,665
Fair Value			369,543
Municipal securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		228,048
Amortized Cost			209,558
Gross Unrealized Gains		118
Gross Unrealized Gains			693
Gross Unrealized Losses		(5,131)
Gross Unrealized Losses			(1,260)
Fair Value		223,035
Fair Value			208,991
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		12,673	13,760
Gross Unrealized Gains		0	0
Gross Unrealized Losses		(2,158)	(1,747)
Fair Value		10,515	12,013
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		62,888
Amortized Cost			0
Gross Unrealized Gains		32
Gross Unrealized Gains			0
Gross Unrealized Losses		(500)
Gross Unrealized Losses			0
Fair Value		62,420
Fair Value			0
Equity securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]		7,408
Gross Unrealized Gains	[1]		194
Gross Unrealized Losses	[1]		(305)
Fair Value	[1]		$ 7,297
Equity securities
Debt and Equity Securities, FV-NI [Line Items]
Equity securities	[1]	$ 29,046
[1]	As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."

Securities - Remaining Contract

Securities - Remaining Contractual Maturity of Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Available-for-sale Securities, Amortized Cost [Abstract]
One year or less	$ 113,814
After one year to five years	171,155
After five years to ten years	199,166
After ten years	0
Securities that do not have a single contractual maturity date	1,766,657
Amortized Cost	2,250,792
Available-for-sale Securities, Fair Value [Abstract]
One year or less	111,859
After one year to five years	168,215
After five years to ten years	195,744
After ten years	0
Securities that do not have a single contractual maturity date	1,703,592
Fair Value	2,179,410
Held-to-maturity Securities, Amortized Cost [Abstract]
One year or less	1,631
After one year to five years	4,915
After five years to ten years	2,176
After ten years	3,951
Securities that do not have a single contractual maturity date	0
Amortized Cost	12,673	$ 13,760
Held-to-maturity Securities, Fair Value [Abstract]
One year or less	1,353
After one year to five years	4,078
After five years to ten years	1,806
After ten years	3,278
Securities that do not have a single contractual maturity date	0
Fair Value	$ 10,515

Securities - Securities Gains (

Securities - Securities Gains (Losses) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gains on sales of securities:
Gross realized gains	$ 0		$ 0
Gross realized gains		$ 3,197,000		$ 3,481,000
Gross realized losses	0		0
Gross realized losses		0		0
Net realized gains on sales of securities	0		0
Net realized gains on sales of securities		3,197,000		3,481,000
Non-cash impairment charges:
Other-than-temporary securities impairment (OTTI)	0	0	0	0
Other-than-temporary securities impairment (OTTI)		0		0
Net realized gains	$ 0		$ 0
Net realized gains		$ 3,197,000		$ 3,481,000

Securities - Additional Informa

Securities - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities pledged	$ 1,400,000,000		$ 1,400,000,000		$ 1,100,000,000
Other-than-temporary securities impairment (OTTI)	$ 0	$ 0	$ 0	$ 0

Securities - Securities In An U

Securities - Securities In An Unrealized Loss Position (Details) $ in Thousands		Sep. 30, 2018USD ($)security	Dec. 31, 2017USD ($)security
Securities Available-for-Sale
Number of Securities | security		987
Number of Securities | security			656
Fair Value
Less Than 12 Months		$ 1,123,559
Less Than 12 Months			$ 613,975
12 Months or Longer		945,973
12 Months or Longer			1,015,438
Total		2,069,532
Total			1,629,413
Unrealized Losses
Less Than 12 Months		25,808
Less Than 12 Months			5,247
12 Months or Longer		45,947
12 Months or Longer			19,776
Total		$ 71,755
Total			$ 25,023
U.S. treasury securities
Securities Available-for-Sale
Number of Securities | security		24
Number of Securities | security			20
Fair Value
Less Than 12 Months		$ 38,623
Less Than 12 Months			$ 19,918
12 Months or Longer		10,486
12 Months or Longer			26,427
Total		49,109
Total			46,345
Unrealized Losses
Less Than 12 Months		307
Less Than 12 Months			87
12 Months or Longer		18
12 Months or Longer			97
Total		$ 325
Total			$ 184
U.S. agency securities
Securities Available-for-Sale
Number of Securities | security		75
Number of Securities | security			72
Fair Value
Less Than 12 Months		$ 81,753
Less Than 12 Months			$ 66,899
12 Months or Longer		54,161
12 Months or Longer			58,021
Total		135,914
Total			124,920
Unrealized Losses
Less Than 12 Months		1,398
Less Than 12 Months			300
12 Months or Longer		1,119
12 Months or Longer			686
Total		$ 2,517
Total			$ 986
CMOs
Securities Available-for-Sale
Number of Securities | security		260
Number of Securities | security			211
Fair Value
Less Than 12 Months		$ 610,183
Less Than 12 Months			$ 365,131
12 Months or Longer		602,362
12 Months or Longer			633,227
Total		1,212,545
Total			998,358
Unrealized Losses
Less Than 12 Months		15,445
Less Than 12 Months			3,265
12 Months or Longer		31,342
12 Months or Longer			14,689
Total		$ 46,787
Total			$ 17,954
MBSs
Securities Available-for-Sale
Number of Securities | security		119
Number of Securities | security			86
Fair Value
Less Than 12 Months		$ 215,463
Less Than 12 Months			$ 126,136
12 Months or Longer		222,989
12 Months or Longer			210,017
Total		438,452
Total			336,153
Unrealized Losses
Less Than 12 Months		5,396
Less Than 12 Months			902
12 Months or Longer		11,099
12 Months or Longer			3,432
Total		$ 16,495
Total			$ 4,334
Municipal securities
Securities Available-for-Sale
Number of Securities | security		501
Number of Securities | security			265
Fair Value
Less Than 12 Months		$ 140,916
Less Than 12 Months			$ 35,500
12 Months or Longer		55,975
12 Months or Longer			81,360
Total		196,891
Total			116,860
Unrealized Losses
Less Than 12 Months		2,762
Less Than 12 Months			479
12 Months or Longer		2,369
12 Months or Longer			781
Total		$ 5,131
Total			$ 1,260
Securities Held-to-Maturity
Number of Securities | security		8	8
Fair Value
Less Than 12 Months		$ 0	$ 0
12 Months or Longer		10,515	12,013
Total		10,515	12,013
Unrealized Losses
Less Than 12 Months		0	0
12 Months or Longer		2,158	1,747
Total		$ 2,158	$ 1,747
Corporate debt securities
Securities Available-for-Sale
Number of Securities | security		8
Fair Value
Less Than 12 Months		$ 36,621
12 Months or Longer		0
Total		36,621
Unrealized Losses
Less Than 12 Months		500
12 Months or Longer		0
Total		$ 500
Equity securities
Securities Available-for-Sale
Number of Securities | security	[1]		2
Fair Value
Less Than 12 Months	[1]		$ 391
12 Months or Longer	[1]		6,386
Total	[1]		6,777
Unrealized Losses
Less Than 12 Months	[1]		214
12 Months or Longer	[1]		91
Total	[1]		$ 305
[1]	As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."

Loans - Loan Portfolio (Details

Loans - Loan Portfolio (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 11,050,548	$ 10,437,812
Deferred loan fees included in total loans	5,887	4,986
Overdrawn demand deposits included in total loans	8,239	8,587
Commercial and industrial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,994,142	3,529,914
Commercial and industrial | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	432,220	430,886
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,462,978	4,553,618
Commercial real estate | Office, retail, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,782,757	1,979,820
Commercial real estate | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	698,611	675,463
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	632,779	539,820
Commercial real estate | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,348,831	1,358,515
Total corporate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	8,889,340	8,514,418
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,161,208	1,923,394
Consumer loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	853,887	827,055
Consumer loans | 1-4 family mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	888,797	774,357
Consumer loans | Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 418,524	$ 321,982

Loans - Loans Sales (Details)

Loans - Loans Sales (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total net gains on loan sales		$ 1,341	$ 2,061	$ 4,475	$ 5,354
Corporate loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales		2,868	11,833	15,180	46,770
Less book value of loans sold		2,827	11,512	14,811	45,752
Total net gains on loan sales	[1]	41	321	369	1,018
1-4 family mortgage loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales		62,576	73,889	193,476	190,544
Less book value of loans sold		61,276	72,149	189,370	186,208
Total net gains on loan sales	[2]	$ 1,300	$ 1,740	$ 4,106	$ 4,336
[1]	Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Condensed Consolidated Statements of Income.
[2]	Net gains on 1-4 family mortgage loan sales are included in mortgage banking income in the Condensed Consolidated Statements of Income.

Acquired and Covered Loans - Ac

Acquired and Covered Loans - Acquired Loans (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Acquired Loans (Details) - Acquired Loans [Line Items]
Non-PCI	[1]	$ 1,128,724	$ 1,524,453
Total	[1]	1,233,668	1,661,906
Acquired loans
Acquired Loans (Details) - Acquired Loans [Line Items]
Non-PCI	[1]	1,121,092	1,512,664
Total	[1]	1,220,015	1,643,358
Covered loans
Acquired Loans (Details) - Acquired Loans [Line Items]
Non-PCI	[1]	7,632	11,789
Total	[1]	13,653	18,548
Receivables acquired with deteriorated credit quality
Acquired Loans (Details) - Acquired Loans [Line Items]
PCI	[1]	104,944	137,453
Receivables acquired with deteriorated credit quality | Acquired loans
Acquired Loans (Details) - Acquired Loans [Line Items]
PCI	[1]	98,923	130,694
Receivables acquired with deteriorated credit quality | Covered loans
Acquired Loans (Details) - Acquired Loans [Line Items]
PCI	[1]	$ 6,021	$ 6,759
[1]	Included in loans in the Consolidated Statements of Condition.

Acquired and Covered Loans - Ad

Acquired and Covered Loans - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Transfers and Servicing [Abstract]
Outstanding balance of PCI loans	$ 157,200		$ 157,200		$ 210,700
Renewed non-purchased credit impaired loans	426,400		426,400		$ 366,000
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Accretion on acquired loans	3,008	$ 4,263	9,548	$ 12,106
Acquired and covered receivables
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Accretion on acquired loans	$ 4,600	$ 7,600	$ 14,100	$ 27,700

Acquired and Covered Loans - Ch

Acquired and Covered Loans - Changes in FDIC Indemnification Asset (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
FDIC Indemnification Asset [Roll Forward]
Beginning balance	$ 2,710	$ 3,918	$ 3,314	$ 4,522
Amortization	(302)	(302)	(906)	(906)
Change in expected reimbursements from the FDIC for changes in expected credit losses	(336)	(123)	(161)	(653)
Net payments to the FDIC	334	123	159	653
Ending balance	$ 2,406	$ 3,616	$ 2,406	$ 3,616

Acquired and Covered Loans - _2

Acquired and Covered Loans - Changes in Accretable Yield (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Changes in Accretable Yield [Roll Forward]
Beginning balances		$ 39,008	$ 39,870	$ 32,957	$ 19,385
Additions		0	0	0	27,316
Accretion		(3,008)	(4,263)	(9,548)	(12,106)
Other	[1]	2,672	478	15,263	1,490
Ending balance		$ 38,672	$ 36,085	$ 38,672	$ 36,085
[1]	Increases represent a rise in the expected future cash flows to be collected over the remaining estimated life of the underlying portfolio, while decreases result from the resolution of certain loans occurring earlier than anticipated.

Past Due Loans, Allowance For_3

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Aging Analysis of Past Due Loans and Non-Performing Loans by Class (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	$ 10,970,233	$ 10,365,369
Total Past Due		80,315	72,443
Total Loans		11,050,548	10,437,812
Non-accrual	[2]	64,766	66,924
90 Days or More Past Due, Still Accruing Interest		2,949	3,555
Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI	[3]	104,944	137,453
Receivables acquired with deteriorated credit quality | Non-accrual
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		688	763
30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		47,981	52,570
90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		32,334	19,873
Commercial, Industrial, and Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans		4,426,362	3,960,800
Commercial, Industrial, and Agricultural | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		3,986	12,702
Commercial, Industrial, and Agricultural | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	3,966,088	3,490,783
Total Past Due		28,054	39,131
Total Loans		3,994,142	3,529,914
Non-accrual	[2]	37,981	40,580
90 Days or More Past Due, Still Accruing Interest		1,096	1,830
Commercial, Industrial, and Agricultural | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	427,702	430,221
Total Past Due		4,518	665
Total Loans		432,220	430,886
Non-accrual	[2]	2,104	219
90 Days or More Past Due, Still Accruing Interest		316	177
Commercial, Industrial, and Agricultural | 30-89 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		15,087	34,620
Commercial, Industrial, and Agricultural | 30-89 Days Past Due | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,156	280
Commercial, Industrial, and Agricultural | 90 Days or More Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		12,967	4,511
Commercial, Industrial, and Agricultural | 90 Days or More Past Due | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,362	385
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	4,427,966	4,534,968
Total Past Due		35,012	18,650
Total Loans		4,462,978	4,553,618
Non-accrual	[2]	14,655	15,767
90 Days or More Past Due, Still Accruing Interest		778	1,053
Commercial real estate | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		81,862	102,813
Commercial real estate | Office, retail, and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	1,767,366	1,970,564
Total Past Due		15,391	9,256
Total Loans		1,782,757	1,979,820
Non-accrual	[2]	6,685	11,560
90 Days or More Past Due, Still Accruing Interest		490	345
Commercial real estate | Office, retail, and industrial | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		11,534	14,575
Commercial real estate | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	691,698	672,098
Total Past Due		6,913	3,365
Total Loans		698,611	675,463
Non-accrual	[2]	3,184	377
90 Days or More Past Due, Still Accruing Interest		0	20
Commercial real estate | Multi-family | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		10,763	14,071
Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	628,976	539,043
Total Past Due		3,803	777
Total Loans		632,779	539,820
Non-accrual	[2]	208	209
90 Days or More Past Due, Still Accruing Interest		0	371
Commercial real estate | Construction | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		3,352	8,843
Commercial real estate | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	1,339,926	1,353,263
Total Past Due		8,905	5,252
Total Loans		1,348,831	1,358,515
Non-accrual	[2]	4,578	3,621
90 Days or More Past Due, Still Accruing Interest		288	317
Commercial real estate | Other commercial real estate | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		56,213	65,324
Commercial real estate | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		22,719	9,016
Commercial real estate | 30-89 Days Past Due | Office, retail, and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		9,640	3,156
Commercial real estate | 30-89 Days Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,729	3,117
Commercial real estate | 30-89 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,595	198
Commercial real estate | 30-89 Days Past Due | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		5,755	2,545
Commercial real estate | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		12,293	9,634
Commercial real estate | 90 Days or More Past Due | Office, retail, and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		5,751	6,100
Commercial real estate | 90 Days or More Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,184	248
Commercial real estate | 90 Days or More Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		208	579
Commercial real estate | 90 Days or More Past Due | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,150	2,707
Total corporate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	8,821,756	8,455,972
Total Past Due		67,584	58,446
Total Loans		8,889,340	8,514,418
Non-accrual	[2]	54,740	56,566
90 Days or More Past Due, Still Accruing Interest		2,190	3,060
Total corporate loans | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		85,848	115,515
Total corporate loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		39,962	43,916
Total corporate loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		27,622	14,530
Consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	2,148,477	1,909,397
Total Past Due		12,731	13,997
Total Loans		2,161,208	1,923,394
Non-accrual	[2]	10,026	10,358
90 Days or More Past Due, Still Accruing Interest		759	495
Consumer loans | Receivables acquired with deteriorated credit quality
Financing Receivable, Recorded Investment, Past Due [Line Items]
PCI		19,096	21,938
Consumer loans | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	848,843	820,099
Total Past Due		5,044	6,956
Total Loans		853,887	827,055
Non-accrual	[2]	5,739	5,946
90 Days or More Past Due, Still Accruing Interest		9	98
Consumer loans | 1-4 family mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	885,556	770,120
Total Past Due		3,241	4,237
Total Loans		888,797	774,357
Non-accrual	[2]	4,287	4,412
90 Days or More Past Due, Still Accruing Interest		41	0
Consumer loans | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	[1]	414,078	319,178
Total Past Due		4,446	2,804
Total Loans		418,524	321,982
Non-accrual	[2]	0	0
90 Days or More Past Due, Still Accruing Interest		709	397
Consumer loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		8,019	8,654
Consumer loans | 30-89 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,995	4,102
Consumer loans | 30-89 Days Past Due | 1-4 family mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,287	2,145
Consumer loans | 30-89 Days Past Due | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		3,737	2,407
Consumer loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		4,712	5,343
Consumer loans | 90 Days or More Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		2,049	2,854
Consumer loans | 90 Days or More Past Due | 1-4 family mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1,954	2,092
Consumer loans | 90 Days or More Past Due | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 709	$ 397
[1]	PCI loans with an accretable yield are considered current.
[2]	Includes PCI loans of $688,000 and $763,000 as of September 30, 2018 and December 31, 2017, respectively, which no longer have an accretable yield as estimates of expected future cash flows have decreased since the acquisition due to credit deterioration.
[3]	Included in loans in the Consolidated Statements of Condition.

Past Due Loans, Allowance For_4

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	$ 97,691	$ 93,371	$ 96,729	$ 87,083
Charge-offs	(9,264)	(10,566)	(37,658)	(21,703)
Recoveries	1,250	2,900	3,811	7,168
Net charge-offs	(8,014)	(7,666)	(33,847)	(14,535)
Provision for loan losses and other	11,248	10,109	38,043	23,266
Ending balance	100,925	95,814	100,925	95,814
Reserve for Unfunded Commitments
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	1,000	1,000	1,000	1,000
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net charge-offs	0	0	0	0
Provision for loan losses and other	0	0	0	0
Ending balance	1,000	1,000	1,000	1,000
Commercial, Industrial, and Agricultural
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	60,043	46,271	55,791	40,709
Charge-offs	(6,277)	(8,935)	(29,609)	(15,966)
Recoveries	416	698	1,707	2,764
Net charge-offs	(5,861)	(8,237)	(27,902)	(13,202)
Provision for loan losses and other	6,776	13,994	33,069	24,521
Ending balance	60,958	52,028	60,958	52,028
Commercial Real Estate
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance			23,392
Ending balance	18,447		18,447
Commercial Real Estate | Office, Retail, and Industrial
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	9,062	15,008	10,996	17,595
Charge-offs	(759)	(14)	(1,525)	(141)
Recoveries	163	1,825	286	2,808
Net charge-offs	(596)	1,811	(1,239)	2,667
Provision for loan losses and other	15	(5,129)	(1,276)	(8,572)
Ending balance	8,481	11,690	8,481	11,690
Commercial Real Estate | Multi-family
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	2,175	2,919	2,534	3,261
Charge-offs	(1)	0	(5)	0
Recoveries	0	2	0	36
Net charge-offs	(1)	2	(5)	36
Provision for loan losses and other	200	(296)	(155)	(672)
Ending balance	2,374	2,625	2,374	2,625
Commercial Real Estate | Construction
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	2,124	4,094	3,481	3,444
Charge-offs	(1)	6	(1)	(38)
Recoveries	5	19	26	258
Net charge-offs	4	25	25	220
Provision for loan losses and other	116	161	(1,262)	616
Ending balance	2,244	4,280	2,244	4,280
Commercial Real Estate | Other Commercial Real Estate
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	4,631	7,479	6,381	7,739
Charge-offs	(177)	(6)	(247)	(721)
Recoveries	154	25	552	205
Net charge-offs	(23)	19	305	(516)
Provision for loan losses and other	740	(257)	(1,338)	18
Ending balance	5,348	7,241	5,348	7,241
Consumer
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance			16,546
Ending balance	20,520		20,520
Consumer | Consumer
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	18,656	16,600	16,546	13,335
Charge-offs	(2,049)	(1,617)	(6,271)	(4,837)
Recoveries	512	331	1,240	1,097
Net charge-offs	(1,537)	(1,286)	(5,031)	(3,740)
Provision for loan losses and other	3,401	1,636	9,005	7,355
Ending balance	$ 20,520	$ 16,950	$ 20,520	$ 16,950

Past Due Loans, Allowance For_5

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Loans and Related Allowance for Credit Losses by Portfolio Segment (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		$ 49,017		$ 51,617
Loans, Collectively Evaluated for Impairment		10,896,587		10,248,742
Loans		11,050,548		10,437,812
Allowance for Credit Losses Individually Evaluated for Impairment		7,904		10,074
Allowance for Credit Losses Collectively Evaluated for Impairment		88,307		82,341
Total Allowance for Credit Losses		100,925	$ 97,691	96,729	$ 95,814	$ 93,371	$ 87,083
PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	[1]	104,944		137,453
Total Allowance for Credit Losses		4,714		4,314
Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		37,309		38,718
Loans, Collectively Evaluated for Impairment		4,385,067		3,909,380
Loans		4,426,362		3,960,800
Allowance for Credit Losses Individually Evaluated for Impairment		6,659		10,074
Allowance for Credit Losses Collectively Evaluated for Impairment		53,919		45,293
Total Allowance for Credit Losses		60,958	60,043	55,791	52,028	46,271	40,709
Commercial and industrial | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		3,986		12,702
Total Allowance for Credit Losses		380		424
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		11,708		12,899
Loans, Collectively Evaluated for Impairment		4,369,408		4,437,906
Loans		4,462,978		4,553,618
Allowance for Credit Losses Individually Evaluated for Impairment		1,245		0
Allowance for Credit Losses Collectively Evaluated for Impairment		14,385		20,515
Total Allowance for Credit Losses		18,447		23,392
Commercial real estate | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		81,862		102,813
Total Allowance for Credit Losses		2,817		2,877
Total corporate loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		49,017		51,617
Loans, Collectively Evaluated for Impairment		8,754,475		8,347,286
Loans		8,889,340		8,514,418
Allowance for Credit Losses Individually Evaluated for Impairment		7,904		10,074
Allowance for Credit Losses Collectively Evaluated for Impairment		68,304		65,808
Total Allowance for Credit Losses		79,405		79,183
Total corporate loans | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		85,848		115,515
Total Allowance for Credit Losses		3,197		3,301
Consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		0		0
Loans, Collectively Evaluated for Impairment		2,142,112		1,901,456
Loans		2,161,208		1,923,394
Allowance for Credit Losses Individually Evaluated for Impairment		0		0
Allowance for Credit Losses Collectively Evaluated for Impairment		19,003		15,533
Total Allowance for Credit Losses		20,520		16,546
Consumer loans | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		19,096		21,938
Total Allowance for Credit Losses		1,517		1,013
Office, retail, and industrial | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		5,639		10,810
Loans, Collectively Evaluated for Impairment		1,765,584		1,954,435
Loans		1,782,757		1,979,820
Allowance for Credit Losses Individually Evaluated for Impairment		1,223		0
Allowance for Credit Losses Collectively Evaluated for Impairment		6,049		9,333
Total Allowance for Credit Losses		8,481	9,062	10,996	11,690	15,008	17,595
Office, retail, and industrial | Commercial real estate | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		11,534		14,575
Total Allowance for Credit Losses		1,209		1,663
Multi-family | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		3,573		621
Loans, Collectively Evaluated for Impairment		684,275		660,771
Loans		698,611		675,463
Allowance for Credit Losses Individually Evaluated for Impairment		0		0
Allowance for Credit Losses Collectively Evaluated for Impairment		2,134		2,436
Total Allowance for Credit Losses		2,374	2,175	2,534	2,625	2,919	3,261
Multi-family | Commercial real estate | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		10,763		14,071
Total Allowance for Credit Losses		240		98
Construction | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		0		0
Loans, Collectively Evaluated for Impairment		629,427		530,977
Loans		632,779		539,820
Allowance for Credit Losses Individually Evaluated for Impairment		0		0
Allowance for Credit Losses Collectively Evaluated for Impairment		2,089		3,331
Total Allowance for Credit Losses		2,244	2,124	3,481	4,280	4,094	3,444
Construction | Commercial real estate | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		3,352		8,843
Total Allowance for Credit Losses		155		150
Other commercial real estate | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		2,496		1,468
Loans, Collectively Evaluated for Impairment		1,290,122		1,291,723
Loans		1,348,831		1,358,515
Allowance for Credit Losses Individually Evaluated for Impairment		22		0
Allowance for Credit Losses Collectively Evaluated for Impairment		4,113		5,415
Total Allowance for Credit Losses		5,348	4,631	6,381	7,241	7,479	7,739
Other commercial real estate | Commercial real estate | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		56,213		65,324
Total Allowance for Credit Losses		1,213		966
Reserve for unfunded commitments
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans, Individually Evaluated for Impairment		0		0
Loans, Collectively Evaluated for Impairment		0		0
Loans		0		0
Allowance for Credit Losses Individually Evaluated for Impairment		0		0
Allowance for Credit Losses Collectively Evaluated for Impairment		1,000		1,000
Total Allowance for Credit Losses		1,000	$ 1,000	1,000	$ 1,000	$ 1,000	$ 1,000
Reserve for unfunded commitments | PCI
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI		0		0
Total Allowance for Credit Losses		$ 0		$ 0
[1]	Included in loans in the Consolidated Statements of Condition.

Past Due Loans, Allowance For_6

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Impaired Loans Individually Evaluated by Class (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	$ 14,644	$ 13,477
Recorded Investment in Loans with a Specific Reserve	34,373	38,140
Unpaid Principal Balance	70,276	69,625
Specific Reserve	7,904	10,074
Commercial and industrial | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	7,534	4,234
Recorded Investment in Loans with a Specific Reserve	27,934	34,484
Unpaid Principal Balance	53,533	53,192
Specific Reserve	6,542	10,074
Commercial and industrial | Agricultural
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	269	0
Recorded Investment in Loans with a Specific Reserve	1,572	0
Unpaid Principal Balance	4,250	0
Specific Reserve	117	0
Commercial real estate
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	6,841	9,243
Recorded Investment in Loans with a Specific Reserve	4,867	3,656
Unpaid Principal Balance	12,493	16,433
Specific Reserve	1,245	0
Commercial real estate | Office, retail, and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	1,636	7,154
Recorded Investment in Loans with a Specific Reserve	4,003	3,656
Unpaid Principal Balance	6,372	14,246
Specific Reserve	1,223	0
Commercial real estate | Multi-family
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	3,573	621
Recorded Investment in Loans with a Specific Reserve	0	0
Unpaid Principal Balance	3,573	621
Specific Reserve	0	0
Commercial real estate | Construction
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	0	0
Recorded Investment in Loans with a Specific Reserve	0	0
Unpaid Principal Balance	0	0
Specific Reserve	0	0
Commercial real estate | Other commercial real estate
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	1,632	1,468
Recorded Investment in Loans with a Specific Reserve	864	0
Unpaid Principal Balance	2,548	1,566
Specific Reserve	$ 22	$ 0

Past Due Loans, Allowance For_7

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Impaired Loans Individually Evaluated by Class (Continued) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		$ 43,683	$ 59,129	$ 49,930	$ 48,850
Interest Income Recognized	[1]	307	368	1,304	1,370
Commercial and industrial | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		28,082	44,682	34,440	32,765
Interest Income Recognized	[1]	123	368	159	924
Commercial and industrial | Agricultural
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		2,372	140	2,153	348
Interest Income Recognized	[1]	0	0	25	0
Commercial real estate
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		13,229	14,307	13,337	15,737
Interest Income Recognized	[1]	184	0	1,120	446
Commercial real estate | Office, retail, and industrial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		6,641	12,496	8,867	13,680
Interest Income Recognized	[1]	105	0	873	262
Commercial real estate | Multi-family
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		3,757	396	2,132	396
Interest Income Recognized	[1]	11	0	66	28
Commercial real estate | Construction
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		0	0	0	9
Interest Income Recognized	[1]	0	0	0	136
Commercial real estate | Other commercial real estate
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		2,831	1,415	2,338	1,652
Interest Income Recognized	[1]	$ 68	$ 0	$ 181	$ 20
[1]	Recorded using the cash basis of accounting.

Past Due Loans, Allowance For_8

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Credit Quality Indicators by Class (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Accruing TDRs		$ 1,741	$ 1,796
Special Mention and Substandard Loans
Financing Receivable, Recorded Investment [Line Items]
Accruing TDRs		639	657
Total corporate loans
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		8,889,340	8,514,418
Total corporate loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		8,493,679	8,197,560
Total corporate loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	244,208	154,601
Total corporate loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	96,713	105,691
Total corporate loans | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	54,740	56,566
Commercial and industrial | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		3,994,142	3,529,914
Accruing TDRs		250	264
Commercial and industrial | Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		3,797,606	3,388,133
Commercial and industrial | Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	134,184	70,863
Commercial and industrial | Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	24,371	30,338
Commercial and industrial | Commercial and industrial | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	37,981	40,580
Commercial and industrial | Agricultural
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		432,220	430,886
Accruing TDRs		0	0
Commercial and industrial | Agricultural | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		411,559	413,946
Commercial and industrial | Agricultural | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	7,591	10,989
Commercial and industrial | Agricultural | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	10,966	5,732
Commercial and industrial | Agricultural | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	2,104	219
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		4,462,978	4,553,618
Accruing TDRs		747	766
Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		4,284,514	4,395,481
Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	102,433	72,749
Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	61,376	69,621
Commercial real estate | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	14,655	15,767
Commercial real estate | Office, retail, and industrial
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		1,782,757	1,979,820
Accruing TDRs		0	0
Commercial real estate | Office, retail, and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		1,721,711	1,903,737
Commercial real estate | Office, retail, and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	19,972	25,546
Commercial real estate | Office, retail, and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	34,389	38,977
Commercial real estate | Office, retail, and industrial | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	6,685	11,560
Commercial real estate | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		698,611	675,463
Accruing TDRs		563	574
Commercial real estate | Multi-family | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		683,199	665,496
Commercial real estate | Multi-family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	10,139	7,395
Commercial real estate | Multi-family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	2,089	2,195
Commercial real estate | Multi-family | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	3,184	377
Commercial real estate | Construction
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		632,779	539,820
Accruing TDRs		0	0
Commercial real estate | Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		601,942	521,911
Commercial real estate | Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	23,477	10,184
Commercial real estate | Construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	7,152	7,516
Commercial real estate | Construction | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	208	209
Commercial real estate | Other commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		1,348,831	1,358,515
Accruing TDRs		184	192
Commercial real estate | Other commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class		1,277,662	1,304,337
Commercial real estate | Other commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[1],[2]	48,845	29,624
Commercial real estate | Other commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[2],[3]	17,746	20,933
Commercial real estate | Other commercial real estate | Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Credit Quality Indicators by Class	[4]	$ 4,578	$ 3,621
[1]	Loans categorized as special mention exhibit potential weaknesses that require the close attention of management since these potential weaknesses may result in the deterioration of repayment prospects in the future.
[2]	Total special mention and substandard loans includes accruing TDRs of $639,000 as of September 30, 2018 and $657,000 as of December 31, 2017.
[3]	Loans categorized as substandard exhibit well-defined weaknesses that may jeopardize the liquidation of the debt. These loans continue to accrue interest because they are well-secured and collection of principal and interest is expected within a reasonable time.
[4]	Loans categorized as non-accrual exhibit well-defined weaknesses that may jeopardize the liquidation of the debt or result in a loss if the deficiencies are not corrected.

Past Due Loans, Allowance For_9

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - Credit Quality Indicators by Class (Continued) (Details) - Consumer loans - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	$ 2,161,208	$ 1,923,394
Performing
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	2,151,182	1,913,036
Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	10,026	10,358
Home equity
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	853,887	827,055
Home equity | Performing
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	848,148	821,109
Home equity | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	5,739	5,946
1-4 family mortgages
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	888,797	774,357
1-4 family mortgages | Performing
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	884,510	769,945
1-4 family mortgages | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	4,287	4,412
Installment
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	418,524	321,982
Installment | Performing
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	418,524	321,982
Installment | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) [Line Items]
Credit Quality Indicators by Class	$ 0	$ 0

Past Due Loans, Allowance Fo_10

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - TDRs By Class (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		$ 1,741	$ 1,796
Non-accrual	[1]	6,365	24,533
Total		8,106	26,329	$ 30,475
Specific reserves related to TDRs		0	2,000
Commercial and industrial | Commercial and industrial
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		250	264
Non-accrual	[1]	5,603	18,959
Total		5,853	19,223
Commercial and industrial | Agricultural
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		0	0
Non-accrual	[1]	0	0
Total		0	0
Commercial real estate
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		747	766
Non-accrual	[1]	0	4,385
Total		747	5,151
Commercial real estate | Office, retail, and industrial
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		0	0
Non-accrual	[1]	0	4,236
Total		0	4,236
Commercial real estate | Multi-family
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		563	574
Non-accrual	[1]	0	149
Total		563	723
Commercial real estate | Construction
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		0	0
Non-accrual	[1]	0	0
Total		0	0
Commercial real estate | Other commercial real estate
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		184	192
Non-accrual	[1]	0	0
Total		184	192
Total corporate loans
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		997	1,030
Non-accrual	[1]	5,603	23,344
Total		6,600	24,374
Consumer loans
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		744	766
Non-accrual	[1]	762	1,189
Total		1,506	1,955
Consumer loans | Home equity
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		83	86
Non-accrual	[1]	352	738
Total		435	824
Consumer loans | 1-4 family mortgages
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		661	680
Non-accrual	[1]	410	451
Total		1,071	1,131
Consumer loans | Installment
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - TDRs By Class [Line Items]
Accruing TDRs		0	0
Non-accrual	[1]	0	0
Total		$ 0	$ 0
[1]	These TDRs are included in non-accrual loans in the preceding tables.

Past Due Loans, Allowance Fo_11

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - TDRs That Were Restructured (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017USD ($)loan	Sep. 30, 2017USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	12	14
Pre- Modification Recorded Investment	$ 29,467	$ 30,389
Funds Disbursed	196	196
Interest and Escrow Capitalized	0	0
Charge-offs	1,736	1,736
Post- Modification Recorded Investment	$ 27,927	$ 28,849
Commercial and industrial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	10	12
Pre- Modification Recorded Investment	$ 25,811	$ 26,733
Funds Disbursed	196	196
Interest and Escrow Capitalized	0	0
Charge-offs	1,736	1,736
Post- Modification Recorded Investment	$ 24,271	$ 25,193
Commercial real estate | Office, retail, and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	2
Pre- Modification Recorded Investment	$ 3,656	$ 3,656
Funds Disbursed	0	0
Interest and Escrow Capitalized	0	0
Charge-offs	0	0
Post- Modification Recorded Investment	$ 3,656	$ 3,656

Past Due Loans, Allowance Fo_12

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRS - TDR Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Troubled Debt Restructuring Activity Rollforward [Roll Forward]
Beginning balance			$ 26,329
Additions		$ 27,927		$ 28,849
Ending balance	$ 8,106	30,475	8,106	30,475
Material commitments to lend additional funds to borrowers with TDRs	0		0		$ 0
Accruing
Troubled Debt Restructuring Activity Rollforward [Roll Forward]
Beginning balance	1,760	2,029	1,796	2,291
Additions	0	14,897	0	15,819
Net payments	(19)	(1,798)	(55)	(1,905)
Net transfers to non-accrual	0	(13,315)	0	(14,392)
Ending balance	1,741	1,813	1,741	1,813
Non-accrual
Troubled Debt Restructuring Activity Rollforward [Roll Forward]
Beginning balance	8,238	3,036	24,533	6,297
Additions	0	14,570	355	14,570
Net payments	(1,620)	(127)	(14,598)	(4,352)
Charge-offs	(253)	(2,132)	(3,925)	(2,245)
Net transfers from accruing	0	13,315	0	14,392
Ending balance	$ 6,365	$ 28,662	$ 6,365	$ 28,662

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income		$ 53,352	$ 38,235	$ 116,462	$ 96,040
Net income applicable to non-vested restricted shares		(441)	(340)	(992)	(910)
Net income applicable to common shares		$ 52,911	$ 37,895	$ 115,470	$ 95,130
Weighted-average common shares outstanding:
Weighted-average common shares outstanding (basic) (in Shares)		102,178	101,752	102,087	101,307
Dilutive effect of common stock equivalents (in Shares)		0	20	5	20
Weighted-average diluted common shares outstanding (in Shares)		102,178	101,772	102,092	101,327
Basic EPS (in dollars per share)		$ 0.52	$ 0.37	$ 1.13	$ 0.94
Diluted EPS (in dollars per share)		$ 0.52	$ 0.37	$ 1.13	$ 0.94
Anti-dilutive shares not included in the computation of diluted EPS (in Shares)	[1]	0	190	36	242
[1]	This amount represents outstanding stock options for which the exercise price is greater than the average market price of the Company's common stock. The final outstanding stock options were exercised during the first quarter of 2018.

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income before income tax expense	$ 59,968	$ 55,942	$ 142,605	$ 144,068
Income tax expense:
Federal income tax expense	2,634	16,355	17,403	41,408
State income tax expense	3,982	1,352	8,740	6,620
Total income tax expense	$ 6,616	$ 17,707	$ 26,143	$ 48,028
Effective income tax rate	11.00%	31.70%	18.30%	33.30%
Certain income tax benefits aligned with federal income tax legislation			$ 7,800

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Fair Value Hedges (Details) - Fair Value Hedging - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross notional amount outstanding		$ 5,083	$ 5,458
Derivative liability fair value in other liabilities		$ (9)	$ (101)
Weighted-average interest rate received		4.11%	3.38%
Weighted-average interest rate paid		5.96%	5.96%
Weighted-average maturity (in years)		1 month 5 days	10 months 2 days
Fair value of derivative	[1]	$ 15	$ 110
[1]	This amount represents the fair value if credit risk related contingent features were triggered.

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	May 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Amount of variable rate loans hedged using interest rate swaps	$ 1,100,000		$ 1,100,000
Amount hedged of borrowed funds using forward starting interest rate swaps	1,000,000		1,000,000		$ 710,000
Amount to be hedged of borrowed funds using forward starting interest rate swaps	$ 320,000		$ 320,000
Weighted-average interest rate to be paid	2.49%		2.49%
Interest rate cash flow hedge loss to be reclassified during next 12 months, net	$ 3,300		$ 3,300
Capital market products income	$ 1,936	$ 2,592	$ 6,313	$ 6,185
Portion of fair value of outstanding interest rate swaps covered by collateral agreements (percent)	100.00%		100.00%			100.00%

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities - Cash Flow Hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross notional amount outstanding		$ 2,170,000	$ 1,960,000
Derivative asset fair value in other assets	[1]	6,009	3,989
Derivative liability fair value in other liabilities	[1]	$ (19,197)	$ (10,219)
Weighted-average interest rate received		2.01%	1.58%
Weighted-average interest rate paid		2.03%	1.61%
Weighted-average maturity (in years)		1 year 9 months 2 days	2 years 2 months 29 days
[1]	Certain cash flow hedges are transacted through a clearinghouse ("centrally cleared") and their change in fair value is settled by the counterparties to the transaction, which results in no fair value.

Derivative Instruments and He_6

Derivative Instruments and Hedging Activities - Other Derivative Instruments (Details) - Other Derivative Instruments - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Gross notional amount outstanding		$ 3,134,222	$ 2,665,358
Derivative asset fair value in other assets	[1]	31,044	17,079
Derivative liability fair value in other liabilities	[1]	(33,832)	(14,930)
Fair value of derivative	[2]	$ 33,974	$ 15,059
[1]	Certain other derivative instruments are centrally cleared and their change in fair value is settled by the counterparties to the transaction, which results in no fair value.
[2]	This amount represents the fair value if credit risk related contingent features were triggered.

Derivative Instruments and He_7

Derivative Instruments and Hedging Activities - Cash Flow Hedge Accounting on AOCI (Details) - Cash Flow Hedging - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest Income
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (losses) recognized in other comprehensive income	$ 2,578	$ 113	$ 13,151	$ 5,465
Reclassification of gains (losses) included in net income	857	946	1,504	4,333
Interest Expense
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (losses) recognized in other comprehensive income	(1,577)	(416)	(11,620)	(3,807)
Reclassification of gains (losses) included in net income	$ (978)	$ (919)	$ (2,087)	$ (3,142)

Derivative Instruments and He_8

Derivative Instruments and Hedging Activities - Effect Of Derivatives On Interest Income (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative, net	$ (145)	$ (12)	$ (666)	$ 1,062
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative, net	(121)	27	(583)	1,191
Interest Income | Fair Value Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative, net	(24)	(39)	(83)	(129)
Interest Income | Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative, net	857	946	1,504	4,333
Interest Expense | Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative, net	$ (978)	$ (919)	$ (2,087)	$ (3,142)

Derivative Instruments and He_9

Derivative Instruments and Hedging Activities - Offsetting Derivatives (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Assets
Gross amounts recognized		$ 37,053	$ 21,068
Less: amounts offset in the Consolidated Statements of Financial Condition		0	0
Net amount presented in the Consolidated Statements of Financial Condition	[1]	37,053	21,068
Offsetting derivative positions		(15,177)	(16,880)
Cash collateral pledged		(20,440)	0
Net credit exposure		1,436	4,188
Liabilities
Gross amounts recognized		53,038	25,250
Less: amounts offset in the Consolidated Statements of Financial Condition		0	0
Net amount presented in the Consolidated Statements of Financial Condition	[1]	53,038	25,250
Offsetting derivative positions		(15,177)	(16,880)
Cash collateral pledged		(3,440)	(8,370)
Net credit exposure		$ 34,421	$ 0
[1]	Included in other assets or other liabilities in the Consolidated Statements of Financial Condition.

Commitments, Guarantees, and _3

Commitments, Guarantees, and Contingent Liabilities (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Other Commitments [Line Items]
Letters of credit		$ 112,225	$ 128,801
Commitments to extend credit
Other Commitments [Line Items]
Commercial, industrial, and agricultural		1,710,789	1,729,426
Commercial real estate		327,279	377,551
Home equity		547,943	514,973
Other commitments	[1]	240,786	244,222
Total commitments to extend credit		$ 2,826,797	$ 2,866,172
[1]	Other commitments includes installment and overdraft protection program commitments.

Fair Value - Recurring Fair Val

Fair Value - Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017		Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Trading securities:
Total trading securities		$ 0		$ 20,447	[1]
Equity securities		29,046		0
Securities Available-for-Sale
Securities available-for-sale, at fair value		2,179,410
Securities available-for-sale, at fair value				1,884,209
Mortgage servicing rights (MSRs)		6,817	$ 6,671	5,894		$ 5,766	$ 5,925	$ 6,120
U.S. treasury securities
Securities Available-for-Sale
Securities available-for-sale, at fair value		49,109
Securities available-for-sale, at fair value				46,345
U.S. agency securities
Securities Available-for-Sale
Securities available-for-sale, at fair value		141,254
Securities available-for-sale, at fair value				156,847
CMOs
Securities Available-for-Sale
Securities available-for-sale, at fair value		1,257,927
Securities available-for-sale, at fair value				1,095,186
MBSs
Securities Available-for-Sale
Securities available-for-sale, at fair value		445,665
Securities available-for-sale, at fair value				369,543
Municipal securities
Securities Available-for-Sale
Securities available-for-sale, at fair value		223,035
Securities available-for-sale, at fair value				208,991
Corporate debt securities
Securities Available-for-Sale
Securities available-for-sale, at fair value		62,420
Securities available-for-sale, at fair value				0
Equity securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[1]			7,297
Recurring | Level 1
Trading securities:
Money market funds		0		1,685
Mutual funds		0		18,762
Total trading securities	[2]	0		20,447
Equity securities	[2]	22,078		0
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	49,109
Securities available-for-sale, at fair value	[2]			46,345
Mortgage servicing rights (MSRs)	[3]	0		0
Derivative assets	[3]	0		0
Liabilities
Derivative liabilities	[4]	0		0
Recurring | Level 1 | U.S. treasury securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	49,109
Securities available-for-sale, at fair value	[2]			46,345
Recurring | Level 1 | U.S. agency securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 1 | CMOs
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 1 | MBSs
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 1 | Municipal securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 1 | Corporate debt securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 1 | Equity securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 2
Trading securities:
Money market funds		0		0
Mutual funds		0		0
Total trading securities	[2]	0		0
Equity securities	[2]	6,968		0
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	2,130,301
Securities available-for-sale, at fair value	[2]			1,837,864
Mortgage servicing rights (MSRs)	[3]	0		0
Derivative assets	[3]	37,053		21,068
Liabilities
Derivative liabilities	[4]	53,038		25,250
Recurring | Level 2 | U.S. treasury securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 2 | U.S. agency securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	141,254
Securities available-for-sale, at fair value	[2]			156,847
Recurring | Level 2 | CMOs
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	1,257,927
Securities available-for-sale, at fair value	[2]			1,095,186
Recurring | Level 2 | MBSs
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	445,665
Securities available-for-sale, at fair value	[2]			369,543
Recurring | Level 2 | Municipal securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	223,035
Securities available-for-sale, at fair value	[2]			208,991
Recurring | Level 2 | Corporate debt securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	62,420
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 2 | Equity securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]			7,297
Recurring | Level 3
Trading securities:
Money market funds		0		0
Mutual funds		0		0
Total trading securities	[2]	0		0
Equity securities	[2]	0		0
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Mortgage servicing rights (MSRs)	[3]	6,817		5,894
Derivative assets	[3]	0		0
Liabilities
Derivative liabilities	[4]	0		0
Recurring | Level 3 | U.S. treasury securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 3 | U.S. agency securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 3 | CMOs
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 3 | MBSs
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 3 | Municipal securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 3 | Corporate debt securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]	$ 0
Securities available-for-sale, at fair value	[2]			0
Recurring | Level 3 | Equity securities
Securities Available-for-Sale
Securities available-for-sale, at fair value	[2]			$ 0
[1]	As a result of accounting guidance adopted in the first quarter of 2018, equity securities are no longer presented within trading securities or securities available-for-sale and are now presented within equity securities in the Consolidated Statements of Financial Condition for the current period. For further discussion of this guidance, see Note 2, "Recent Accounting Pronouncements."
[2]	As a result of recently adopted accounting guidance, equity securities are no longer presented within trading securities or securities available-for-sale for the prior period and are now presented within equity securities for the current period. For further discussion of this guidance, see Note 2 of "Notes to the Condensed Consolidated Financial Statements" in Item 1 of this Form 10-Q.
[3]	Included in other assets in the Consolidated Statements of Financial Condition.
[4]	Included in other liabilities in the Consolidated Statements of Financial Condition.

Fair Value - Significant Unobse

Fair Value - Significant Unobservable Inputs Used In the Valuation of MSRs (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Total amount of loans being serviced for the benefit of others at the end of the period	$ 624.9	$ 607
Minimum
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed	6.60%	4.20%
Maturity (months)	2 months	6 months
Discount rate	9.50%	9.50%
Maximum
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed	13.10%	13.10%
Maturity (months)	106 months	92 months
Discount rate	12.00%	12.00%

Fair Value - Carrying Value of

Fair Value - Carrying Value of Mortgage Servicing Rights (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance		$ 6,671	$ 5,925	$ 5,894	$ 6,120
New MSRs		324	161	893	522
Total gains (losses) included in earnings:
Changes in valuation inputs and assumptions	[1]	65	(121)	627	(209)
Other changes in fair value	[1],[2]	(243)	(199)	(597)	(667)
Ending balance		6,817	5,766	6,817	5,766
Contractually servicing fees earned	[1]	$ 375	$ 379	$ 1,122	$ 1,158
[1]	Included in mortgage banking income in the Condensed Consolidated Statements of Income and related to assets held as of September 30, 2018 and 2017.
[2]	Primarily represents changes in expected future cash flows due to payoffs and paydowns.

Fair Value - Assets Measured At

Fair Value - Assets Measured At Fair Value On A Non-Recurring Basis (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
OREO		$ 12,244	$ 20,851
Nonrecurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	[1]	0	0
OREO	[2]	0	0
Loans held-for-sale	[3]	0	0
Assets held-for-sale	[4]	0	0
Nonrecurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	[1]	0	0
OREO	[2]	0	0
Loans held-for-sale	[3]	0	0
Assets held-for-sale	[4]	0	0
Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral-dependent impaired loans	[1]	28,077	33,240
OREO	[2]	7,075	12,340
Loans held-for-sale	[3]	6,020	21,098
Assets held-for-sale	[4]	$ 4,659	$ 2,208
[1]	Includes impaired loans with charge-offs and impaired loans with a specific reserve during the periods presented.
[2]	Includes OREO with fair value adjustments subsequent to initial transfer that occurred during the periods presented.
[3]	Included in other assets in the Consolidated Statements of Financial Condition.
[4]	Included in premises, furniture, and equipment in the Consolidated Statements of Financial Condition.

Fair Value - Narrative (Details

Fair Value - Narrative (Details)	Sep. 30, 2018
Minimum
Fair Value (Details) [Line Items]
Appraisal adjustment (percent)	0.00%
Maximum
Fair Value (Details) [Line Items]
Appraisal adjustment (percent)	15.00%

Fair Value - Fair Value Measure

Fair Value - Fair Value Measurements of Other Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 185,239	$ 192,800
Interest-bearing deposits in other banks	111,360	153,770
Securities held-to-maturity	12,673	13,760
FHLB and FRB stock	87,728	69,708
Loans	10,950,623	10,342,083
Investment in BOLI	284,074	279,900
Liabilities
Deposits	11,527,114	11,053,325
Borrowed funds	1,073,546	714,884
Senior and subordinated debt	195,595	195,170
Carrying Amount | Level 1
Assets
Cash and due from banks	185,239	192,800
Carrying Amount | Level 2
Assets
Interest-bearing deposits in other banks	111,360	153,770
Securities held-to-maturity	12,673	13,760
FHLB and FRB stock	87,728	69,708
Liabilities
Deposits	11,527,114	11,053,325
Borrowed funds	1,073,546	714,884
Senior and subordinated debt	195,595	195,170
Accrued interest payable	6,406	4,704
Carrying Amount | Level 3
Assets
Loans	10,953,029	10,345,397
Investment in BOLI	284,074	279,900
Accrued interest receivable	51,856	45,261
Other interest-earning assets	33	228
Fair Value | Level 1
Assets
Cash and due from banks	185,239	192,800
Fair Value | Level 2
Assets
Interest-bearing deposits in other banks	111,360	153,770
Securities held-to-maturity	10,515	12,013
FHLB and FRB stock	87,728	69,708
Liabilities
Deposits	11,505,442	11,038,819
Borrowed funds	1,073,546	714,884
Senior and subordinated debt	209,917	208,666
Accrued interest payable	6,406	4,704
Fair Value | Level 3
Assets
Loans	10,587,311	10,059,992
Investment in BOLI	284,074	279,900
Accrued interest receivable	51,856	45,261
Other interest-earning assets	$ 33	$ 228