First Midwest Bancorp (ONBPP) 10-K 28 Feb 17 2016 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 24, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	FIRST MIDWEST BANCORP INC
Entity Central Index Key	702,325
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 1,377,487,826
Entity Common Stock, Shares Outstanding		102,611,121

Consolidated Statements of Fina

Consolidated Statements of Financial Condition - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and due from banks	$ 155,055	$ 114,587
Interest-bearing deposits in other banks	107,093	266,615
Trading securities, at fair value	17,920	16,894
Securities available-for-sale, at fair value	1,919,450	1,306,636
Securities held-to-maturity, at amortized cost (fair value 2016 – $18,212; 2015 – $20,054)	22,291	23,152
Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock, at cost	59,131	39,306
Loans	8,254,145	7,161,715
Allowance for loan losses	(86,083)	(73,630)
Net loans	8,168,062	7,088,085
Other real estate owned (OREO)	26,083	27,782
Premises, furniture, and equipment, net	82,577	122,278
Investment in bank-owned life insurance (BOLI)	219,746	209,601
Goodwill and other intangible assets	366,876	339,277
Accrued interest receivable and other assets	278,271	178,463
Total assets	11,422,555	9,732,676
Liabilities
Noninterest-bearing deposits	2,766,748	2,414,454
Interest-bearing deposits	6,061,855	5,683,284
Total deposits	8,828,603	8,097,738
Borrowed funds	879,008	165,096
Senior and subordinated debt	194,603	201,208
Accrued interest payable and other liabilities	263,261	122,366
Total liabilities	10,165,475	8,586,408
Stockholders' Equity
Common stock	913	882
Additional paid-in capital	498,937	446,672
Retained earnings	1,016,674	953,516
Accumulated other comprehensive loss, net of tax	(40,910)	(28,389)
Treasury stock, at cost	(218,534)	(226,413)
Total stockholders' equity	1,257,080	1,146,268
Total liabilities and stockholders' equity	$ 11,422,555	$ 9,732,676

Consolidated Statements of Fin3

Consolidated Statements of Financial Condition (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Securities held-to-maturity, at fair value	$ 18,212	$ 20,054
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	91,284,000	88,228,000
Common stock, shares outstanding	81,325,000	77,952,000
Treasury stock, shares	9,959,000	10,276,000

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest Income
Loans	$ 337,998	$ 300,303	$ 265,501
Investment securities – taxable	28,724	18,082	14,516
Investment securities – tax-exempt	8,737	13,861	16,716
Other short-term investments	2,873	3,738	3,131
Total interest income	378,332	335,984	299,864
Interest Expense
Deposits	9,863	9,527	10,377
Borrowed funds	6,313	2,314	573
Senior and subordinated debt	12,465	12,545	12,062
Total interest expense	28,641	24,386	23,012
Net interest income	349,691	311,598	276,852
Provision for loan losses	30,983	21,152	19,168
Net interest income after provision for loan losses	318,708	290,446	257,684
Noninterest Income
Service charges on deposit accounts	40,665	39,979	36,910
Wealth management fees	33,071	29,162	26,474
Card-based fees	29,104	26,984	24,340
Merchant servicing fees	12,533	11,739	11,260
Mortgage banking income	10,162	5,741	4,011
Capital market products income	10,024	4,806	2,231
Other service charges, commissions, and fees	9,542	8,848	5,855
Net gain on sale-leaseback transaction	5,509	0	0
BOLI income	3,647	4,185	2,873
Net securities gains	1,420	2,373	8,097
Other income	3,635	2,764	4,567
Total noninterest income	159,312	136,581	126,618
Noninterest Expense
Salaries and wages	151,341	133,739	116,578
Retirement and other employee benefits	33,309	31,852	27,245
Net occupancy and equipment expense	41,154	38,720	35,181
Professional services	25,122	22,720	23,436
Technology and related costs	14,765	14,581	12,875
Merchant card expense	10,782	9,886	9,195
Advertising and promotions	7,787	7,606	8,159
Federal Deposit Insurance Corporation (FDIC) premiums	6,268	6,017	5,824
Net OREO expense	3,024	5,281	7,075
Cardholder expense	5,812	5,243	4,251
Other expenses	24,834	21,601	20,135
Acquisition and integration related expenses	14,352	1,389	13,872
Lease cancellation fee	950	0	0
Property valuation adjustments	0	8,581	0
Total noninterest expense	339,500	307,216	283,826
Income before income tax expense	138,520	119,811	100,476
Income tax expense	46,171	37,747	31,170
Net income	$ 92,349	$ 82,064	$ 69,306
Per Common Share Data
Basic earnings per common share (in dollars per share)	$ 1.14	$ 1.05	$ 0.92
Diluted earnings per common share (in dollars per share)	$ 1.14	$ 1.05	$ 0.92
Weighted-average common shares outstanding (in shares)	79,797	77,059	74,484
Weighted-average diluted common shares outstanding (in shares)	79,810	77,072	74,496

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 92,349	$ 82,064	$ 69,306
Unrealized holding (losses) gains:
Before tax	(19,204)	(9,824)	37,173
Tax effect	7,682	3,906	(14,918)
Net of tax	(11,522)	(5,918)	22,255
Reclassification of net gains included in net income:
Before tax	1,420	2,373	8,097
Tax effect	(568)	(970)	(3,311)
Net of tax	852	1,403	4,786
Net unrealized holding (losses) gains	(12,374)	(7,321)	17,469
Derivative Instruments
Before tax	2,175	(2,233)	(1,930)
Tax effect	(883)	903	792
Net of tax	1,292	(1,330)	(1,138)
Unrealized holding losses:
Before tax	(2,002)	(6,570)	(9,127)
Tax effect	563	2,687	3,733
Net of tax	(1,439)	(3,883)	(5,394)
Total other comprehensive (loss) income	(12,521)	(12,534)	10,937
Total comprehensive income	$ 79,828	$ 69,530	$ 80,243

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income - AOCI - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive income (loss)	$ (12,521)	$ (12,534)	$ 10,937
Accumulated Unrealized Loss on Securities Available- for-Sale
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(10,271)	(2,950)	(20,419)
Other comprehensive income (loss)	(12,374)	(7,321)	17,469
Ending balance	(22,645)	(10,271)	(2,950)
Accumulated Unrealized Loss on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(2,468)	(1,138)	0
Other comprehensive income (loss)	1,292	(1,330)	(1,138)
Ending balance	(1,176)	(2,468)	(1,138)
Unrecognized Net Pension Costs
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(15,650)	(11,767)	(6,373)
Other comprehensive income (loss)	(1,439)	(3,883)	(5,394)
Ending balance	(17,089)	(15,650)	(11,767)
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(28,389)	(15,855)	(26,792)
Other comprehensive income (loss)	(12,521)	(12,534)	10,937
Ending balance	$ (40,910)	$ (28,389)	$ (15,855)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders’ Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Balance at Beginning at Dec. 31, 2013	$ 1,001,442	$ 858	$ 414,293	$ 853,740	$ (26,792)	$ (240,657)
Balance at Beginning (in shares) at Dec. 31, 2013		75,071
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	69,306			69,306
Other comprehensive income (loss)	10,937				10,937
Common dividends declared ($0.31, $0.36 and $0.36)	(23,530)			(23,530)
Acquisition, net of issuance costs	38,300	$ 24	38,276
Acquisition, net of issuance costs (in shares)		2,441
Restricted stock activity	(1,975)		(8,560)			6,585
Restricted stock activity (in shares)		176
Treasury stock issued to benefit plans	369		(137)			506
Treasury stock issued to benefit plans (in shares)		7
Share-based compensation expense	5,926		5,926
Balance at Ending at Dec. 31, 2014	1,100,775	$ 882	449,798	899,516	(15,855)	(233,566)
Balance at Ending (in shares) at Dec. 31, 2014		77,695
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	82,064			82,064
Other comprehensive income (loss)	(12,534)				(12,534)
Common dividends declared ($0.31, $0.36 and $0.36)	(28,064)			(28,064)
Acquisition, net of issuance costs	0
Purchase of treasury stock	(120)					(120)
Purchase of treasury stock (in shares)		(7)
Restricted stock activity	(3,296)		(10,236)			6,940
Restricted stock activity (in shares)		267
Treasury stock issued to benefit plans	201		(132)			333
Treasury stock issued to benefit plans (in shares)		(3)
Share-based compensation expense	7,242		7,242
Balance at Ending at Dec. 31, 2015	$ 1,146,268	$ 882	446,672	953,516	(28,389)	(226,413)
Balance at Ending (in shares) at Dec. 31, 2015	77,952	77,952
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 92,349			92,349
Other comprehensive income (loss)	(12,521)				(12,521)
Common dividends declared ($0.31, $0.36 and $0.36)	(29,191)			(29,191)
Acquisition, net of issuance costs	54,896	$ 31	54,865
Acquisition, net of issuance costs (in shares)		3,042
Common stock issued	227		227
Common stock issued (in shares)		13
Restricted stock activity	(2,673)		(10,685)			8,012
Restricted stock activity (in shares)		326
Treasury stock issued to benefit plans	(154)		(21)			(133)
Treasury stock issued to benefit plans (in shares)		(8)
Share-based compensation expense	7,879		7,879
Balance at Ending at Dec. 31, 2016	$ 1,257,080	$ 913	$ 498,937	$ 1,016,674	$ (40,910)	$ (218,534)
Balance at Ending (in shares) at Dec. 31, 2016	81,325	81,325

Consolidated Statements of Cha8

Consolidated Statements of Changes in Stockholders’ Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock
Common dividends declared per common share (in dollars per share)	$ 0.36	$ 0.36	$ 0.31

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income		$ 92,349	$ 82,064	$ 69,306
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses		30,983	21,152	19,168
Depreciation of premises, furniture, and equipment		12,804	13,367	12,224
Net amortization of premium on securities		13,653	4,849	8,218
Net securities gains		(1,420)	(2,373)	(8,097)
Gains on sales of 1-4 family mortgages and corporate loans held-for-sale		(8,931)	(6,847)	(4,069)
Net losses on early extinguishment of debt		0	0	2,059
Net losses on sales and valuation adjustments of OREO		1,196	2,631	3,325
Amortization of the FDIC indemnification asset		1,185	1,461	3,315
Net (gains) losses on sales and valuation adjustments of premises, furniture, and equipment		(4,762)	7,718	(3,277)
BOLI income		(3,647)	(4,185)	(2,873)
Net pension (income) cost		(513)	622	(959)
Share-based compensation expense	[1]	7,879	7,242	5,926
Tax expense related to share-based compensation		(685)	(1,200)	(106)
Provision for deferred income tax (benefit) expense		(1,367)	16,897	16,215
Amortization of other intangible assets		4,682	3,920	2,889
Originations of mortgage loans held-for-sale		(238,192)	(158,699)	(97,535)
Proceeds from sales of mortgage loans held-for-sale		246,642	158,791	96,006
Net (increase) decrease in trading securities		(1,026)	566	(143)
Net (increase) decrease in accrued interest receivable and other assets		(76,902)	10,023	(18,015)
Net increase (decrease) in accrued interest payable and other liabilities		47,118	(1,042)	22,367
Net cash provided by operating activities		121,046	156,957	125,944
Investing Activities
Proceeds from maturities, repayments, and calls of securities available-for-sale		360,303	322,764	172,001
Proceeds from sales of securities available-for-sale		53,186	93,909	27,805
Purchases of securities available-for-sale		(933,317)	(509,481)	(25,856)
Proceeds from maturities, repayments, and calls of securities held-to-maturity		8,077	4,645	4,675
Purchases of securities held-to-maturity		(5,352)	(1,242)	(2,638)
Purchases of FHLB stock		(18,276)	(1,190)	(427)
Net increase in loans		(714,213)	(399,807)	(279,654)
Proceeds from claims on BOLI, net of premiums paid		1,588	1,082	(85)
Proceeds from sales of OREO		7,539	18,572	22,368
Proceeds from sales of premises, furniture, and equipment		152,863	1,230	3,906
Purchases of premises, furniture, and equipment		(19,083)	(11,269)	(14,085)
Net cash received from (paid for) acquisitions		57,347	(16,047)	200,645
Net cash (used in) provided by investing activities		(1,049,338)	(496,834)	108,655
Financing Activities
Net increase (decrease) in deposit accounts		135,944	118,167	(73,244)
Net increase (decrease) in borrowed funds		711,496	25,902	(1,288)
Purchase of treasury stock		0	(120)	0
Net proceeds from the issuance of subordinated debt		146,484	0	0
Payments for the retirement of senior and subordinated debt		(153,500)	0	0
Payment for the termination of FHLB advances		0	0	(116,609)
Cash dividends paid		(29,198)	(27,036)	(22,568)
Restricted stock activity		(2,476)	(2,890)	(2,781)
Excess tax benefit related to share-based compensation		488	794	912
Net cash provided by (used in) financing activities		809,238	114,817	(215,578)
Net (decrease) increase in cash and cash equivalents		(119,054)	(225,060)	19,021
Cash and cash equivalents at beginning of year		381,202	606,262	587,241
Cash and cash equivalents at end of year		262,148	381,202	606,262
Supplemental Disclosures of Cash Flow Information:
Income taxes paid		57,553	25,022	16,375
Interest paid to depositors and creditors		27,400	24,535	23,088
Dividends declared, but unpaid		7,243	7,250	6,222
Common stock issued for acquisitions, net of issuance costs		54,896	0	38,300
Non-cash transfers of loans to OREO		4,173	13,504	18,079
Non-cash transfers of loans held-for-investment to loans held-for-sale		$ 93,981	$ 57,130	$ 76,446
[1]	Comprised of restricted stock, restricted stock unit, and performance share awards expense.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Operations – First Midwest Bancorp, Inc. (the "Company") is a bank holding company that was incorporated in Delaware in 1982 and began operations on March 31, 1983. The Company is headquartered in Itasca, Illinois and has operations located primarily throughout the Chicago metropolitan area, as well as northwest Indiana, central and western Illinois, and eastern Iowa. The Company operates three wholly-owned subsidiaries: First Midwest Bank (the "Bank"), Catalyst Asset Holdings, LLC ("Catalyst"), and Parasol Investment Management, LLC ("Parasol"). The Bank conducts the majority of the Company's operations. Catalyst manages certain non-performing assets of the Company. Parasol serves in an advisory capacity to certain wealth management accounts with the Bank. The Company is engaged in commercial and retail banking and offers a broad range of banking, treasury, and wealth management products and services, tailored to the needs of its commercial and industrial, commercial real estate, municipal, and consumer customers. Basis of Presentation – 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 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. Segment Disclosures – The Company has one reportable segment. The Company's chief operating decision maker evaluates the operations of the Company using consolidated information for purposes of allocating resources and assessing performance. Therefore, segment disclosures are not required. The following is a summary of the Company's significant accounting policies. 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 Consolidated Statements of Income from the effective date of the acquisition. Cash and Cash Equivalents – For purposes of the Consolidated Statements of Cash Flows, management defines cash and cash equivalents to include cash and due from banks, interest-bearing deposits in other banks, and other short-term investments, if any, such as federal funds sold and securities purchased under agreements to resell. Securities – Securities are classified as held-to-maturity, trading, or available-for-sale at the time of purchase. Securities Held-to-Maturity – Securities classified as held-to-maturity are securities for which management has the intent and ability to hold to maturity. These securities are stated at cost and adjusted for amortization of premiums and accretion of discounts over the estimated lives of the securities using the effective interest method. Trading Securities – The Company's trading securities consist of diversified investment securities held in a grantor trust under deferred compensation arrangements in which plan participants may direct amounts earned to be invested in securities other than Company stock. The accounts of the grantor trust are consolidated with the accounts of the Company in its consolidated financial statements. Trading securities are reported at fair value. Other than the securities held in the grantor trust, the Company does not carry any securities for trading purposes. Securities Available-for-Sale – All other securities are classified as available-for-sale. Securities available-for-sale are carried at fair value with unrealized gains and losses, net of related deferred income taxes, recorded in stockholders' equity as a separate component of accumulated other comprehensive loss. The historical cost of debt securities is adjusted for amortization of premiums and accretion of discounts over the estimated life of the security using the effective interest method. Amortization of premiums and accretion of discounts are included in interest income. Purchases and sales of securities are recognized on a trade date basis. Realized securities gains or losses are reported in net securities gains in the Consolidated Statements of Income. The cost of securities sold is based on the specific identification method. On a quarterly basis, the Company individually assesses securities with unrealized losses to determine whether there were any events or circumstances indicating that an other-than-temporary impairment ("OTTI") has occurred. In evaluating OTTI, the Company considers many factors, including (i) the severity and duration of the impairment, (ii) the financial condition and near-term prospects of the issuer, including external credit ratings and recent downgrades for debt securities, (iii) its intent to hold the security until its value recovers, and (iv) the likelihood that it will be required to sell the security before a recovery in value, which may be at maturity. If management intends to sell the security or believes it is more likely than not that it will be required to sell the security prior to full recovery, an OTTI charge will be recognized through income as a realized loss and included in net securities gains in the Consolidated Statements of Income. If management does not expect to sell the security or believes it is not more likely than not that it will be required to sell the security prior to full recovery, the OTTI is separated into the amount related to credit deterioration, which is recognized through income as a realized loss, and the amount resulting from other factors, which is recognized in other comprehensive (loss) income. FHLB and FRB Stock – The Company, as a member of the FHLB and FRB, is required to maintain an investment in the capital stock of the FHLB and FRB. No ready market exists for these stocks, and they have no quoted market values. The stock is redeemable at par by the FHLB and FRB and is, therefore, carried at cost and periodically evaluated for impairment. 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 consist of loans acquired by the Company in 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. During 2015, certain covered loans were no longer covered under the FDIC Agreements, and are included in acquired loans and no longer classified as covered 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 certain smaller balance 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 ("TDRs") – 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 TDRs when the modification is short-term or results in an insignificant delay in payments. The Company's TDRs 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 TDRs 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 a TDR until it is paid in full or charged-off. Impaired Loans – Impaired loans consist of corporate non-accrual loans and TDRs. 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 TDRs, 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. OREO – OREO consists of properties acquired through foreclosure in partial or total satisfaction of defaulted loans. At initial transfer into OREO, properties are recorded at fair value, less estimated selling costs. Subsequently, OREO is carried at the lower of the cost basis or fair value, less estimated selling costs. OREO write-downs occurring at the transfer date are charged against the allowance for loan losses, establishing a new cost basis. Subsequent to the initial transfer, the carrying values of OREO may be adjusted through a valuation allowance to reflect reductions in value resulting from new appraisals, new list prices, changes in market conditions, or changes in disposition strategies. Increases in value can be recognized through a reduction in the valuation allowance, but may not exceed the established cost basis. These valuation adjustments, along with expenses related to maintenance of the properties, are included in net OREO expense in the Consolidated Statements of Income. FDIC Indemnification Asset – The majority of loans and OREO acquired through FDIC-assisted transactions are covered by 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 indemnification period. The FDIC indemnification asset represents the present value of expected future reimbursements from the FDIC. Since the indemnified items are covered loans and covered OREO, which are initially measured at fair value, the FDIC indemnification asset is also initially measured at fair value by discounting the expected future cash flows to be received from the FDIC. These expected future cash flows are estimated by multiplying estimated losses on covered PCI loans and covered OREO by the reimbursement rates in the FDIC Agreements. The balance of the FDIC indemnification asset is adjusted periodically to reflect changes in expected future cash flows. Decreases in estimated reimbursements from the FDIC are recorded prospectively through amortization and increases in estimated reimbursements from the FDIC are recognized by an increase in the carrying value of the indemnification asset. Payments from the FDIC for reimbursement of losses result in a reduction of the FDIC indemnification asset. Depreciable Assets – Premises, furniture, and equipment are stated at cost, less accumulated depreciation. Depreciation expense is determined by the straight-line method over the estimated useful lives of the assets. Useful lives range from 3 to 10 years for furniture and equipment and 25 to 40 years for premises. Leasehold improvements are amortized over the shorter of the life of the asset or the lease term. Gains on dispositions are included in other noninterest income and losses on dispositions are included in other noninterest expense in the Consolidated Statements of Income. Maintenance and repairs are charged to operating expenses as incurred, while improvements that extend the useful life of assets are capitalized and depreciated over the estimated remaining life. Certain assets, such as buildings and land, that the Company intends to sell and meets held-for-sale criteria are transferred into the held-for-sale category at the lower of their fair value, as determined by a current appraisal, or their recorded investment. Long-lived depreciable assets are evaluated periodically for impairment when events or changes in circumstances indicate the carrying amount may not be recoverable. Impairment exists when the undiscounted expected future cash flows of a long-lived asset are less than its carrying value. In that event, the Company recognizes a loss for the difference between the carrying amount and the estimated fair value of the asset based on a quoted market price, if applicable, or a discounted cash flow analysis. Impairment losses are recorded in other noninterest expense in the Consolidated Statements of Income. BOLI – BOLI represents life insurance policies on the lives of certain Company directors and officers for which the Company is the sole owner and beneficiary. These policies are recorded as an asset in the Consolidated Statements of Financial Condition at their cash surrender value ("CSV") or the current amount that could be realized if settled. The change in CSV and insurance proceeds received are included as a component of noninterest income in the Consolidated Statements of Income. Goodwill and Other Intangible Assets – Goodwill represents the excess of the purchase price of the acquisition over the fair value of the net tangible and intangible assets acquired using the acquisition method of accounting. Goodwill is not amortized. Instead, impairment testing is conducted annually as of October 1 or more often if events or circumstances between annual tests indicate that there may be impairment. Impairment testing is performed using either a qualitative or quantitative approach at the reporting unit level. All of the Company's goodwill is allocated to First Midwest Bancorp, Inc., which is the Company's only applicable reporting unit for purposes of testing goodwill for impairment. The Company performs impairment testing using a qualitative approach to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. Qualitative factors include, but are not limited to, macroeconomic conditions, industry and market specific conditions and trends, the Company's financial performance, market capitalization, stock price, and Company-specific events relevant to the assessment. If the assessment of qualitative factors indicates that it is not more likely than not that an impairment exists, no further testing is performed; otherwise, the Company would proceed with a quantitative two-step goodwill impairment test. In the first step, the Company compares its estimate of the fair value of the reporting unit, which is based on a discounted cash flow analysis, with its carrying amount, including goodwill. If the fair value of the reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired and the second step is not required. If necessary, the second step compares the implied fair value of the reporting unit goodwill with the carrying amount of that goodwill. The implied fair value of goodwill is determined by assigning the value of the reporting unit to all of the assets and liabilities of that unit, including any other identifiable intangible assets. An impairment loss is recognized if the carrying amount of the reporting unit goodwill exceeds the implied fair value of goodwill. Other intangible assets represent purchased assets that lack physical substance, but can be distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset, or liability. Identified intangible assets that have a finite useful life are amortized over that life in a manner that reflects the estimated decline in the economic value of the identified intangible asset. All of the Company's other intangible assets have finite lives and are amortized over varying periods not exceeding 13 years. Intangible assets are reviewed for impairment annually or more frequently when events or circumstances indicate that its carrying amount may not be recoverable. Wealth Management – Assets held in a fiduciary or agency capacity for customers are not included in the consolidated financial statements as they are not assets of the Company or its subsidiaries. Fee income is recognized on an accrual basis and is included as a component of noninterest income in the Consolidated Statements of Income. 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 and quarterly thereafter, 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. 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. Ineffectiveness is calculated based on the change in fai

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS Adopted Accounting Pronouncements Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern: In August of 2014, the Financial Accounting Standards Board ("FASB") issued guidance that requires management to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued. The guidance is effective for the annual and interim periods ending after December 15, 2016. The adoption of this guidance on December 31, 2016 did not impact the Company's financial condition, results of operations, or liquidity. Amendments to Consolidation Analysis: In February of 2015, the FASB issued guidance that updates current accounting for the consolidation of certain legal entities. This guidance modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities ("VIEs") or voting interest entities, eliminates the presumption that a general partner should consolidate a limited partnership, affects the consolidation analysis of reporting entities that are involved with VIEs, and provides certain exceptions from consolidation guidance for certain reporting entities. This guidance is effective for annual and interim periods beginning after December 15, 2015. The adoption of this guidance on January 1, 2016 did not materially impact the Company's financial condition, results of operations, or liquidity. Simplifying the Presentation of Debt Issuance Costs: In April of 2015, the FASB issued guidance to clarify the presentation of debt issuance costs within the balance sheet. Additionally, the guidance requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by this amendment. The guidance is effective for annual and interim periods beginning after December 15, 2015. The adoption of this guidance on January 1, 2016 did not materially impact the Company's financial condition, results of operations, or liquidity. Accounting Pronouncements Pending Adoption Revenue from Contracts with Customers: In May of 2014, the 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 was initially effective for annual and interim reporting periods beginning on or after December 15, 2016 but was deferred to December 15, 2017, and must be applied either retrospectively or using the modified retrospective approach. Early adoption is permitted, but not before the original effective date. The Company’s revenue is comprised of net interest income on financial assets and liabilities, which are excluded from the scope of this guidance, and noninterest income. The Company expects that this guidance will change how revenue from certain revenue streams is recognized within wealth management fees but does not expect these changes to have a significant impact on the Company’s financial condition, results of operations, or liquidity. The Company continues to evaluate the impact of this guidance on other components of noninterest income. 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 changes in fair value will be recognized in net income unless the investments qualify for a new practicability exception. This guidance also requires entities to recognize changes in instrument-specific credit risk related to financial liabilities measured under the fair value option in other comprehensive income. No changes were made to the guidance for classifying and measuring investments in debt securities and loans. This guidance is effective for annual and interim periods beginning after December 15, 2017. 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. 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. During the third quarter of 2016, the Company entered into a sale-leaseback transaction that resulted in a deferred gain of $82.5 million , with $81.0 million remaining as of December 31, 2016. Upon adoption of this guidance, the remaining deferred gain 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 ." Management is evaluating the new guidance and the additional impact to the Company's financial condition, results of operations, or liquidity. Contingent Put and Call Options in Debt Instruments: In March of 2016, the FASB issued final guidance clarifying the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. Entities are required to apply the guidance to existing debt instruments (or hybrid financial instruments that are determined to have a debt host) using a modified retrospective transition method as of the period of adoption. This guidance is effective for annual and interim periods beginning after December 15, 2016. 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. Equity Method Accounting: In March of 2016, the FASB issued final guidance to simplify the equity method of accounting. The guidance eliminates the requirement to retrospectively apply equity method accounting in previous periods when an investor initially obtains significant influence over an investee. This guidance is effective for annual and interim periods beginning after December 15, 2016. 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. Accounting for Employee Share-based Payments: In March of 2016, the FASB issued guidance to simplify the accounting for employee share-based payment transactions. The guidance requires entities to recognize the income tax effects of awards in the income statement when the awards vest or are settled. In addition, the guidance allows entities to repurchase more of an employee's shares than it can under current guidance for tax withholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur. This guidance is effective for annual and interim reporting periods beginning on or after December 15, 2016. Early adoption is permitted. Management is evaluating the new guidance, but does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. 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 new guidance and the impact to the Company's financial condition, results of operations, and 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. This guidance is effective for annual and interim reporting periods beginning on or after December 15, 2017. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's Consolidated Statement of Cash Flows. Update to Amendments to Consolidation Analysis: In October of 2016, the FASB issued guidance that changes how a single decision maker will consider its indirect interests when performing the primary beneficiary analysis under the VIE model. This guidance is effective for annual and interim periods beginning after December 15, 2016. 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. 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. This guidance is effective for annual and interim periods beginning after December 15, 2017. 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. 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. This guidance is effective for annual and interim periods beginning after December 15, 2017. 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. 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.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS Pending Acquisitions Standard Bancshares, Inc. On June 28, 2016, the Company entered into a definitive agreement to acquire Standard Bancshares, Inc. ("Standard"), the holding company for Standard Bank and Trust Company. On January 6, 2017, the Company completed its acquisition of Standard. With the acquisition, the Company acquired all assets and assumed all liabilities of Standard including 35 banking offices located primarily in the southwest Chicago suburbs and adjacent markets in northwest Indiana, total assets of $2.6 billion , $2.0 billion in deposits, and $1.8 billion in loans. For additional discussion and disclosure related to the Standard acquisition, see note 25 , " Subsequent Events ." Completed Acquisitions NI Bancshares Corporation On March 8, 2016 , the Company completed its acquisition of NI Bancshares Corporation ("NI Bancshares"), the holding company for The National Bank & Trust Company of Sycamore. As part of the acquisition, the Company acquired all assets and assumed all liabilities of NI Bancshares, which included ten banking offices in northern Illinois and over $700.0 million in trust assets under management. The merger consideration was a combination of Company common stock and cash, at a purchase price of $70.1 million . Goodwill of $21.8 million associated with the acquisition was recorded by the Company. During 2016, the Company updated the fair value adjustments associated with the NI Bancshares transaction, which required a measurement period adjustment of $1.0 million to increase goodwill. This adjustment was recognized in the current period in accordance with accounting guidance applicable to business combinations. The fair value adjustments associated with these accounts and goodwill remain preliminary and may change as the Company continues to finalize the fair value of the assets and liabilities acquired. Peoples Bancorp, Inc On December 3, 2015 , the Company completed its acquisition of Peoples Bancorp, Inc. ("Peoples") and its wholly-owned banking subsidiary, The Peoples' Bank of Arlington Heights. With the acquisition, the Company acquired all assets and assumed all liabilities of Peoples, which included two banking offices in Arlington Heights, Illinois, at a purchase price of $16.8 million paid in cash. The Company recorded goodwill of $7.7 million associated with the acquisition. During 2016, the Company finalized the fair value adjustments associated with the Peoples transaction, which required a measurement period adjustment of $121,000 to increase goodwill. These adjustments were recognized in the current period in accordance with accounting guidance applicable to business combinations. The following table presents the assets acquired and liabilities assumed, net of the fair value adjustments, in the NI Bancshares and Peoples transactions as of the acquisition date, including measurement period adjustments. The assets acquired and liabilities assumed, both intangible and tangible, were recorded at their estimated fair values as of the acquisition date and have been accounted for under the acquisition method of accounting. Acquisition Activity (Dollar amounts in thousands, except share and per share data) NI Bancshares Peoples March 8, 2016 December 3, 2015 Assets Cash and due from banks and interest-bearing deposits in other banks $ 72,533 $ 781 Securities available-for-sale 125,843 41,492 Securities held-to-maturity 1,864 — FHLB and FRB stock 1,549 558 Loans 396,886 53,766 OREO 2,863 515 Investment in BOLI 8,384 — Goodwill 21,751 7,665 Other intangible assets 10,409 580 Premises, furniture, and equipment 19,636 2,215 Accrued interest receivable and other assets 16,558 2,941 Total assets $ 678,276 $ 110,513 Liabilities Noninterest-bearing deposits $ 130,909 $ 15,869 Interest-bearing deposits 464,012 75,944 Total deposits 594,921 91,813 Borrowed funds 2,416 1,200 Intangible liabilities 230 — Accrued interest payable and other liabilities 10,627 672 Total liabilities 608,194 93,685 Consideration Paid Common stock (2016 - 3,042,494 shares issued at $18.059 per share), net of $48,000 in issuance costs 54,896 — Cash paid 15,186 16,828 Total consideration paid 70,082 16,828 $ 678,276 $ 110,513 Expenses related to the acquisition and integration of completed and pending transactions totaled $14.4 million , $1.4 million and $13.9 million during the years ended December 31, 2016 , 2015 and 2014 , respectively, and are reported as a separate component within noninterest expense in the Consolidated Statements of Income. The completed acquisitions were not considered material to the Company's financial statements; therefore, pro forma financial data and related disclosures are not included.

Securities

Securities	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Securities	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 December 31, 2016 2015 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 48,581 $ 26 $ (66 ) $ 48,541 $ 17,000 $ 15 $ (35 ) $ 16,980 U.S. agency securities 183,528 519 (410 ) 183,637 86,461 351 (169 ) 86,643 Collateralized mortgage 1,064,130 969 (17,653 ) 1,047,446 695,198 1,072 (9,085 ) 687,185 Other mortgage-backed 337,139 1,395 (5,879 ) 332,655 152,481 1,920 (871 ) 153,530 Municipal securities 273,319 1,245 (3,718 ) 270,846 321,437 6,443 (310 ) 327,570 Trust-preferred collateralized debt obligations ("CDOs") 47,681 261 (14,682 ) 33,260 48,287 34 (16,792 ) 31,529 Equity securities 3,206 147 (288 ) 3,065 3,282 86 (169 ) 3,199 Total securities available-for-sale $ 1,957,584 $ 4,562 $ (42,696 ) $ 1,919,450 $ 1,324,146 $ 9,921 $ (27,431 ) $ 1,306,636 Securities Held-to-Maturity Municipal securities $ 22,291 $ — $ (4,079 ) $ 18,212 $ 23,152 $ — $ (3,098 ) $ 20,054 Trading Securities $ 17,920 $ 16,894 Remaining Contractual Maturity of Securities (Dollar amounts in thousands) As of December 31, 2016 Available-for-Sale Held-to-Maturity Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 73,669 $ 71,428 $ 2,336 $ 1,909 After one year to five years 429,166 416,112 6,834 5,583 After five years to ten years 2,592 2,513 2,975 2,431 After ten years 47,682 46,231 10,146 8,289 Securities that do not have a single contractual maturity date 1,404,475 1,383,166 — — Total $ 1,957,584 $ 1,919,450 $ 22,291 $ 18,212 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 $1.1 billion as of December 31, 2016 and $856.9 million as of December 31, 2015 . No securities held-to-maturity were pledged as of December 31, 2016 or 2015 . Excluding securities issued or backed by the U.S. government and its agencies and U.S. government-sponsored enterprises, there were no investments in securities from one issuer that exceeded 10% of total stockholders' equity as of December 31, 2016 or 2015 . During the years ended December 31, 2016, 2015, and 2014 there were no material gross trading gains (losses). The following table presents net realized gains on securities available-for-sale for the three years ended December 31, 2016. Securities Available-for-Sale Gains (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Gains on sales of securities: Gross realized gains $ 1,589 $ 2,519 $ 8,188 Gross realized losses (169 ) (146 ) (63 ) Net realized gains on sales of securities 1,420 2,373 8,125 Non-cash impairment charges: OTTI — — (28 ) Net realized gains $ 1,420 $ 2,373 $ 8,097 During 2016, net securities gains consisted primarily of sales of municipal securities at gains of $1.1 million and sales of MBSs, CMOs, and equity securities at net gains of $304,000 . Net securities gains consisted primarily of sales of MBSs at gains of $1.9 million and sales of CMOs, municipal securities, and other investments at net gains of $521,000 during 2015. The sale of a non-accrual CDO at a gain of $3.5 million and other investments at gains totaling $4.6 million comprised net securities gains during 2014. 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 (loss) income. The following table presents a rollforward of life-to-date OTTI recognized in earnings related to all securities available-for-sale held by the Company for the years ended December 31, 2016 , 2015 , and 2014 . The majority of the beginning and ending balance of OTTI relates to CDOs currently held by the Company. Changes in OTTI Recognized in Earnings (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 23,345 $ 23,516 $ 32,422 OTTI included in earnings (1) : Losses on securities that previously had OTTI — — 28 Losses on securities that did not previously have OTTI — — — Reduction for securities sales (2) — (171 ) (8,934 ) Ending balance $ 23,345 $ 23,345 $ 23,516 (1) Included in net securities gains in the Consolidated Statements of Income. (2) These reductions were driven by the sale of one CMO with a carrying value of $1.3 million during the year ended December 31, 2015 and one CDO with a carrying value of $1.3 million and one municipal security with a carrying value of $357,000 during the year ended December 31, 2014. The following table presents the aggregate amount of unrealized losses and the aggregate related fair values of securities with unrealized losses as of December 31, 2016 and 2015 . Securities in an Unrealized Loss Position (Dollar amounts in thousands) Less Than 12 Months Greater Than 12 Months Total Number of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses As of December 31, 2016 Securities Available-for-Sale U.S. treasury securities 16 $ 33,505 $ 61 $ 3,995 $ 5 $ 37,500 $ 66 U.S. agency securities 28 62,064 364 11,814 46 73,878 410 CMOs 194 523,233 10,309 411,758 7,344 934,991 17,653 MBSs 68 221,174 4,726 77,780 1,154 298,954 5,880 Municipal securities 380 133,957 3,059 29,280 659 163,237 3,718 CDOs 7 — — 30,592 14,682 30,592 14,682 Equity securities 2 404 201 2,319 86 2,723 287 Total 695 $ 974,337 $ 18,720 $ 567,538 $ 23,976 $ 1,541,875 $ 42,696 Securities Held-to-Maturity Municipal securities 14 $ — $ — $ 18,212 $ 4,079 $ 18,212 $ 4,079 As of December 31, 2015 Securities Available-for-Sale U.S. treasury securities 4 $ 7,946 $ 35 $ — $ — $ 7,946 $ 35 U.S. agency securities 10 30,620 169 — — 30,620 169 CMOs 133 309,787 3,110 257,362 5,975 567,149 9,085 MBSs 27 63,028 427 31,980 444 95,008 871 Municipal securities 68 8,135 65 24,227 245 32,362 310 CDOs 8 8,034 971 21,642 15,821 29,676 16,792 Equity securities 2 485 120 2,305 49 2,790 169 Total 252 $ 428,035 $ 4,897 $ 337,516 $ 22,534 $ 765,551 $ 27,431 Securities Held-to-Maturity Municipal securities 19 $ 20,054 $ 3,098 $ — $ — $ 20,054 $ 3,098 Substantially all of the Company's CMOs 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 December 31, 2016 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. The unrealized losses on CDOs as of December 31, 2016 reflect changes in market activity for these securities. Management does not believe these unrealized losses represent OTTI related to credit deterioration. In addition, the Company does not intend to sell the CDOs with unrealized losses, and the Company does not believe it is more likely than not that it will be required to sell them before recovery of their amortized cost basis, which may be at maturity. Significant judgment is required to calculate the fair value of the CDOs. For a detailed discussion of the CDO valuation methodology, see Note 22 , " Fair Value ."

Loans

Loans	12 Months Ended
	Dec. 31, 2016
Receivables [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 December 31, 2016 2015 Commercial and industrial $ 2,827,658 $ 2,524,726 Agricultural 389,496 387,440 Commercial real estate: Office, retail, and industrial 1,581,827 1,395,454 Multi-family 614,034 528,324 Construction 451,540 216,882 Other commercial real estate 979,359 931,190 Total commercial real estate 3,626,760 3,071,850 Total corporate loans 6,843,914 5,984,016 Home equity 732,604 653,468 1-4 family mortgages 416,354 355,854 Installment 237,999 137,602 Total consumer loans 1,386,957 1,146,924 Covered loans (1) 23,274 30,775 Total loans $ 8,254,145 $ 7,161,715 Deferred loan fees included in total loans $ 3,838 $ 5,191 Overdrawn demand deposits included in total loans 7,836 2,810 (1) For information on covered loans, see Note 6 , " Acquired and Covered Loans ." 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. Commercial and industrial loans are underwritten after evaluating and understanding the borrower's ability to operate its business. As part of the underwriting process, the Company examines current and expected future cash flows to determine the ability of the borrower to repay its obligation. Commercial and industrial loans are primarily made based on the identified cash flows of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of the borrower may not be as expected, and the collateral securing these loans may fluctuate in value due to economic or other factors. Most commercial and industrial loans are secured by the assets being financed or other business assets, such as accounts receivable or inventory, and may incorporate a personal guarantee. Some short-term loans may be made on an unsecured basis. In the case of loans secured by accounts receivable, the availability of funds for the repayment of these loans substantially depend on the ability of the borrower to collect amounts due from its customers. Agricultural loans are generally provided to meet seasonal production, equipment, and farm real estate borrowing needs of individual and corporate crop and livestock producers. As part of the underwriting process, the Company examines projected future cash flows, financial statement stability, and the value of the underlying collateral. Seasonal crop production loans are repaid by the liquidation of the financed crop that is typically covered by crop insurance. Equipment and real estate term loans are repaid through cash flows of the farming operation. Commercial real estate loans are subject to underwriting standards and processes similar to commercial and industrial loans. The repayment of commercial real estate loans depends on the successful operation of the property securing the loan or the business conducted on the property securing the loan. This category of loans may be more adversely affected by conditions in the real estate market. Management monitors and evaluates commercial real estate loans based on cash flow, collateral, geography, and risk rating criteria. The mix of properties securing the loans in our commercial real estate portfolio are balanced between owner-occupied and investor categories and are diverse in terms of type and geographic location, generally within the Company's markets. Construction loans are generally based on estimates of costs and values associated with the completed project and are underwritten utilizing feasibility studies, independent appraisal reviews, sensitivity analyses of absorption and lease rates, and financial analyses of the developers and property owners. Sources of repayment may be permanent loans from long-term lenders, sales of developed property, or an interim loan commitment until permanent financing is obtained. Generally, construction loans have a higher risk profile than other real estate loans since repayment is impacted by real estate values, interest rate changes, governmental regulation of real property, demand and supply of alternative real estate, the availability of long-term financing, and changes in general economic conditions. Consumer loans are centrally underwritten using a credit scoring model developed by the Fair Isaac Corporation ("FICO"), which employs a risk-based system to determine the probability that a borrower may default. Underwriting standards for home equity loans are heavily influenced by statutory requirements, which include loan-to-value and affordability ratios, risk-based pricing strategies, and documentation requirements. The home equity category consists mainly of revolving lines of credit secured by junior liens on owner-occupied real estate. Loan-to-value ratios on home equity loans and 1-4 family mortgages are based on the current appraised value of the collateral. The carrying value of loans that were pledged to secure liabilities as of December 31, 2016 and 2015 are presented below. Carrying Value of Loans Pledged (Dollar amounts in thousands) As of December 31 2016 2015 Loans pledged to secure: FHLB advances $ 3,667,202 $ 3,057,421 FRB's Discount Window Primary Credit Program 777,950 841,808 Total $ 4,445,152 $ 3,899,229 Loan Sales The following table presents loan sales for the years ended December 31, 2016 , 2015 , and 2014 . Loan Sales (Dollar amounts in thousands) As of December 31, 2016 2015 2014 Corporate loan sales Proceeds from sales $ 54,681 $ 31,091 $ 23,222 Less book value of loans sold 52,821 29,535 22,924 Net gain on corporate sales (1) $ 1,860 $ 1,556 $ 298 1-4 family mortgage loan sales Proceeds from sales $ 290,383 $ 185,308 $ 148,680 Less book value of loans sold 283,312 180,017 144,909 Net gain on 1-4 family mortgage sales (2) 7,071 5,291 3,771 Total net gains on loan sales $ 8,931 $ 6,847 $ 4,069 (1) Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Consolidated Statements of Income. (2) Net gains on mortgage loan sales are included in mortgage banking income in the 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. The Company also retained limited recourse for credit losses on the sold loans. A description of the recourse obligation is presented in Note 21 , " Commitments, Guarantees, and Contingent Liabilities ."

Acquired and Covered Loans

Acquired and Covered Loans	12 Months Ended
	Dec. 31, 2016
Acquired Loans [Abstract]
Acquired and Covered Loans	ACQUIRED AND COVERED LOANS Covered loans consist of loans acquired by the Company in FDIC-assisted transactions which are covered by the FDIC Agreements. Acquired loans consist of all other loans that were acquired in business combinations that are not covered by the FDIC Agreements. Both acquired and covered loans are included in loans in the Consolidated Statements of Financial Condition. The significant accounting policies related to acquired and covered loans, which are classified as PCI and Non-PCI, and the related FDIC indemnification asset are presented in Note 1 , " Summary of Significant Accounting Policies ." During 2015, non-residential mortgage loans related to three FDIC-assisted transactions were no longer covered under the FDIC Agreements. These non-residential loans, which totaled $14.9 million and $21.0 million as of December 31, 2016 and 2015 , respectively, are included in acquired loans and no longer classified as covered loans. The losses on residential mortgage loans will continue to be covered under the FDIC Agreements through various dates between December 31, 2019 and September 30, 2020. The following table presents acquired and covered PCI and Non-PCI loans as of December 31, 2016 and 2015 . Acquired and Covered Loans (Dollar amounts in thousands) As of December 31, 2016 2015 PCI Non-PCI Total PCI Non-PCI Total Acquired loans $ 53,772 $ 613,339 $ 667,111 $ 50,286 $ 534,506 $ 584,792 Covered loans 7,895 15,379 23,274 9,919 20,856 30,775 Total acquired and covered loans $ 61,667 $ 628,718 $ 690,385 $ 60,205 $ 555,362 $ 615,567 Acquired Non-PCI loans that are renewed are no longer classified as acquired loans. These loans totaled $117.6 million and $61.6 million as of December 31, 2016 and 2015 , 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 December 31, 2016 , 2015 , and 2014 . Rollforwards of the carrying value of the FDIC indemnification asset for the three years ended December 31, 2016 is presented in the following table. Changes in the FDIC Indemnification Asset (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 3,903 $ 8,452 $ 16,585 Amortization (1,185 ) (1,461 ) (3,315 ) Change in expected reimbursements from the FDIC for changes in expected credit losses 330 1,313 (481 ) Net payments to (from) the FDIC 1,474 (4,401 ) (4,337 ) Ending balance $ 4,522 $ 3,903 $ 8,452 Changes in the accretable yield for acquired and covered PCI loans were as follows. Changes in Accretable Yield (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 24,912 $ 28,244 $ 36,792 Additions 3,981 1,168 3,517 Accretion (8,063 ) (11,311 ) (12,535 ) Other (1) (1,444 ) 6,811 470 Ending balance $ 19,386 $ 24,912 $ 28,244 (1) Decreases result from the resolution of certain loans occurring earlier than anticipated while increases represent a rise in the expected future cash cash flows to be collected over the remaining estimated life of the underlying portfolio. Total accretion on acquired and covered PCI and non-PCI loans for December 31, 2016 , 2015 , and 2014 was $14.6 million , $16.3 million , and $13.6 million , respectively.

Past Due Loans, Allowance For C

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 and 2015 . 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 30-89 Days Past Due 90 Days or More Past Due Total Past Due Total Loans Non-accrual 90 Days or More Past Due, Still Accruing Interest As of December 31, 2016 Commercial and industrial $ 2,816,442 $ 6,426 $ 4,790 $ 11,216 $ 2,827,658 $ 29,938 $ 374 Agricultural 388,596 — 900 900 389,496 181 736 Commercial real estate: Office, retail, and industrial 1,563,867 5,327 12,633 17,960 1,581,827 17,277 1,129 Multi-family 612,428 858 748 1,606 614,034 311 604 Construction 450,927 332 281 613 451,540 286 — Other commercial real estate 974,406 1,307 3,646 4,953 979,359 2,892 1,526 Total commercial real estate 3,601,628 7,824 17,308 25,132 3,626,760 20,766 3,259 Total corporate loans 6,806,666 14,250 22,998 37,248 6,843,914 50,885 4,369 Home equity 726,676 3,627 2,301 5,928 732,604 4,986 17 1-4 family mortgages 412,737 2,652 965 3,617 416,354 2,939 231 Installment 236,264 1,476 259 1,735 237,999 — 259 Total consumer loans 1,375,677 7,755 3,525 11,280 1,386,957 7,925 507 Covered loans 22,097 918 259 1,177 23,274 479 133 Total loans $ 8,204,440 $ 22,923 $ 26,782 $ 49,705 $ 8,254,145 $ 59,289 $ 5,009 As of December 31, 2015 Commercial and industrial $ 2,516,197 $ 4,956 $ 3,573 $ 8,529 $ 2,524,726 $ 5,587 $ 857 Agricultural 387,109 245 86 331 387,440 355 — Commercial real estate: Office, retail, and industrial 1,386,383 2,647 6,424 9,071 1,395,454 6,875 4 Multi-family 526,625 541 1,158 1,699 528,324 796 548 Construction 216,377 — 505 505 216,882 905 — Other commercial real estate 922,531 3,575 5,084 8,659 931,190 5,611 661 Total commercial real estate 3,051,916 6,763 13,171 19,934 3,071,850 14,187 1,213 Total corporate loans 5,955,222 11,964 16,830 28,794 5,984,016 20,129 2,070 Home equity 647,175 3,247 3,046 6,293 653,468 5,310 216 1-4 family mortgages 350,980 2,680 2,194 4,874 355,854 3,416 528 Installment 136,780 753 69 822 137,602 20 69 Total consumer loans 1,134,935 6,680 5,309 11,989 1,146,924 8,746 813 Covered loans 29,808 405 562 967 30,775 555 174 Total loans $ 7,119,965 $ 19,049 $ 22,701 $ 41,750 $ 7,161,715 $ 29,430 $ 3,057 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 years ended December 31, 2016 , 2015 , and 2014 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 Covered Loans Reserve for Unfunded Commitments Total Allowance for Credit Losses As of December 31, 2016 Beginning balance $ 37,074 $ 13,116 $ 2,462 $ 1,440 $ 6,088 $ 11,812 $ 1,638 $ 1,225 $ 74,855 Charge-offs (9,844 ) (4,707 ) (307 ) (134 ) (2,932 ) (5,229 ) (140 ) — (23,293 ) Recoveries 2,451 337 97 56 524 1,298 — — 4,763 Net charge-offs (7,393 ) (4,370 ) (210 ) (78 ) (2,408 ) (3,931 ) (140 ) — (18,530 ) Provision for loan 11,028 8,788 1,002 2,082 4,050 4,613 (580 ) (225 ) 30,758 Ending Balance $ 40,709 $ 17,534 $ 3,254 $ 3,444 $ 7,730 $ 12,494 $ 918 $ 1,000 $ 87,083 As of December 31, 2015 Beginning balance $ 29,458 $ 10,992 $ 2,249 $ 2,297 $ 8,327 $ 12,145 $ 7,226 $ 1,816 $ 74,510 Charge-offs (15,885 ) (2,887 ) (545 ) (136 ) (2,643 ) (4,187 ) (634 ) — (26,917 ) Recoveries 2,573 467 15 350 1,993 1,183 120 — 6,701 Net charge-offs (13,312 ) (2,420 ) (530 ) 214 (650 ) (3,004 ) (514 ) — (20,216 ) Provision for loan losses and other 20,928 4,544 743 (1,071 ) (1,589 ) 2,671 (5,074 ) (591 ) 20,561 Ending balance $ 37,074 $ 13,116 $ 2,462 $ 1,440 $ 6,088 $ 11,812 $ 1,638 $ 1,225 $ 74,855 As of December 31, 2014 Beginning balance $ 30,381 $ 10,405 $ 2,017 $ 6,316 $ 10,817 $ 13,010 $ 12,559 $ 1,616 $ 87,121 Charge-offs (17,424 ) (7,345 ) (943 ) (1,052 ) (4,834 ) (7,574 ) (1,012 ) — (40,184 ) Recoveries 3,800 497 87 166 1,727 729 1,199 — 8,205 Net charge-offs (13,624 ) (6,848 ) (856 ) (886 ) (3,107 ) (6,845 ) 187 — (31,979 ) Provision for loan 12,701 7,435 1,088 (3,133 ) 617 5,980 (5,520 ) 200 19,368 Ending balance $ 29,458 $ 10,992 $ 2,249 $ 2,297 $ 8,327 $ 12,145 $ 7,226 $ 1,816 $ 74,510 The table below provides a breakdown of loans and the related allowance for credit losses by portfolio segment as of December 31, 2016 and 2015 . 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 December 31, 2016 Commercial, industrial, and $ 24,645 $ 3,189,327 $ 3,182 $ 3,217,154 $ 507 $ 39,554 $ 648 $ 40,709 Commercial real estate: Office, retail, and industrial 16,287 1,553,234 12,306 1,581,827 — 16,148 1,386 17,534 Multi-family 398 601,429 12,207 614,034 — 3,059 195 3,254 Construction 34 447,058 4,448 451,540 — 3,280 164 3,444 Other commercial real estate 1,286 965,900 12,173 979,359 18 6,613 1,099 7,730 Total commercial real estate 18,005 3,567,621 41,134 3,626,760 18 29,100 2,844 31,962 Total corporate loans 42,650 6,756,948 44,316 6,843,914 525 68,654 3,492 72,671 Consumer — 1,377,501 9,456 1,386,957 — 12,101 393 12,494 Covered loans — 15,379 7,895 23,274 — 109 809 918 Reserve for unfunded — — — — — 1,000 — 1,000 Total loans $ 42,650 $ 8,149,828 $ 61,667 $ 8,254,145 $ 525 $ 81,864 $ 4,694 $ 87,083 As of December 31, 2015 Commercial, industrial, and $ 2,871 $ 2,902,361 $ 6,934 $ 2,912,166 $ 883 $ 35,378 $ 813 $ 37,074 Commercial real estate: Office, retail, and industrial 6,162 1,376,789 12,503 1,395,454 715 10,833 1,568 13,116 Multi-family 800 526,037 1,487 528,324 — 2,367 95 2,462 Construction 178 212,671 4,033 216,882 — 1,160 280 1,440 Other commercial real estate 3,665 913,161 14,364 931,190 — 5,367 721 6,088 Total commercial real estate 10,805 3,028,658 32,387 3,071,850 715 19,727 2,664 23,106 Total corporate loans 13,676 5,931,019 39,321 5,984,016 1,598 55,105 3,477 60,180 Consumer — 1,135,959 10,965 1,146,924 — 11,425 387 11,812 Covered loans — 20,856 9,919 30,775 — 248 1,390 1,638 Reserve for unfunded — — — — — 1,225 — 1,225 Total loans $ 13,676 $ 7,087,834 $ 60,205 $ 7,161,715 $ 1,598 $ 68,003 $ 5,254 $ 74,855 Loans Individually Evaluated for Impairment The following table presents loans individually evaluated for impairment by class of loan as of December 31, 2016 and 2015 . PCI loans are excluded from this disclosure. Impaired Loans Individually Evaluated by Class (Dollar amounts in thousands) As of December 31, 2016 2015 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 $ 11,579 $ 13,066 $ 29,514 $ 507 $ 1,673 $ 1,198 $ 4,592 $ 883 Agricultural — — — — — — — — Commercial real estate: Office, retail, and industrial 16,287 — 21,057 — 4,654 1,508 12,083 715 Multi-family 398 — 398 — 800 — 941 — Construction 34 — 34 — 178 — 299 — Other commercial real estate 1,016 270 2,141 18 3,665 — 4,403 — Total commercial real 17,735 270 23,630 18 9,297 1,508 17,726 715 Total impaired loans $ 29,314 $ 13,336 $ 53,144 $ 525 $ 10,970 $ 2,706 $ 22,318 $ 1,598 The following table presents the average recorded investment and interest income recognized on impaired loans by class for the years ended December 31, 2016 , 2015 , and 2014 . PCI loans are excluded from this disclosure. Average Recorded Investment and Interest Income Recognized on Impaired Loans by Class (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Average Recorded Investment Interest Income Recognized (1) Average Recorded Investment Interest Income Recognized (1) Average Interest (1) Commercial and industrial $ 9,178 $ 104 $ 8,940 $ 163 $ 16,137 $ 371 Agricultural — — — — — — Commercial real estate: Office, retail, and industrial 12,867 291 9,359 52 19,003 245 Multi-family 479 11 855 13 1,245 5 Construction 63 — 3,902 118 5,764 — Other commercial real estate 2,809 86 3,310 44 6,014 138 Total commercial real estate 16,218 388 17,426 227 32,026 388 Total impaired loans $ 25,396 $ 492 $ 26,366 $ 390 $ 48,163 $ 759 (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, excluding covered loans, as of December 31, 2016 and 2015 . Corporate Credit Quality Indicators by Class, Excluding Covered Loans (Dollar amounts in thousands) Pass Special (1)(4) Substandard (2)(4) Non-accrual (3) Total As of December 31, 2016 Commercial and industrial $ 2,638,833 $ 92,340 $ 66,547 $ 29,938 $ 2,827,658 Agricultural 366,382 17,039 5,894 181 389,496 Commercial real estate: Office, retail, and industrial 1,491,030 34,007 39,513 17,277 1,581,827 Multi-family 607,324 4,370 2,029 311 614,034 Construction 438,946 111 12,197 286 451,540 Other commercial real estate 951,115 11,808 13,544 2,892 979,359 Total commercial real estate 3,488,415 50,296 67,283 20,766 3,626,760 Total corporate loans $ 6,493,630 $ 159,675 $ 139,724 $ 50,885 $ 6,843,914 As of December 31, 2015 Commercial and industrial $ 2,379,992 $ 86,263 $ 52,884 $ 5,587 $ 2,524,726 Agricultural 381,523 — 5,562 355 387,440 Commercial real estate: Office, retail, and industrial 1,320,164 32,627 35,788 6,875 1,395,454 Multi-family 517,412 6,146 3,970 796 528,324 Construction 201,496 4,678 9,803 905 216,882 Other commercial real estate 898,746 13,179 13,654 5,611 931,190 Total commercial real estate 2,937,818 56,630 63,215 14,187 3,071,850 Total corporate loans $ 5,699,333 $ 142,893 $ 121,661 $ 20,129 $ 5,984,016 (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 a well-defined weakness 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 a well-defined weakness 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 TDRs of $834,000 as of December 31, 2016 and $862,000 as of December 31, 2015 . Consumer Credit Quality Indicators by Class, Excluding Covered Loans (Dollar amounts in thousands) Performing Non-accrual Total As of December 31, 2016 Home equity $ 727,618 $ 4,986 $ 732,604 1-4 family mortgages 413,415 2,939 416,354 Installment 237,999 — 237,999 Total consumer loans $ 1,379,032 $ 7,925 $ 1,386,957 As of December 31, 2015 Home equity $ 648,158 $ 5,310 $ 653,468 1-4 family mortgages 352,438 3,416 355,854 Installment 137,582 20 137,602 Total consumer loans $ 1,138,178 $ 8,746 $ 1,146,924 TDRs TDRs 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 TDRs by class as of December 31, 2016 and 2015 . See Note 1 , " Summary of Significant Accounting Policies ," for the accounting policy for TDRs. TDRs by Class (Dollar amounts in thousands) As of December 31, 2016 2015 Accruing Non-accrual (1) Total Accruing Non-accrual (1) Total Commercial and industrial $ 281 $ 150 $ 431 $ 294 $ 1,050 $ 1,344 Agricultural — — — — — — Commercial real estate: Office, retail, and industrial 155 4,733 4,888 164 — 164 Multi-family 586 168 754 598 186 784 Construction — — — — — — Other commercial real estate 268 48 316 340 — 340 Total commercial real estate 1,009 4,949 5,958 1,102 186 1,288 Total corporate loans 1,290 5,099 6,389 1,396 1,236 2,632 Home equity 177 820 997 494 667 1,161 1-4 family mortgages 824 378 1,202 853 421 1,274 Installment — — — — — — Total consumer loans 1,001 1,198 2,199 1,347 1,088 2,435 Total loans $ 2,291 $ 6,297 $ 8,588 $ 2,743 $ 2,324 $ 5,067 (1) These TDRs are included in non-accrual loans in the preceding tables. TDRs are included in the calculation of the allowance for credit losses in the same manner as impaired loans. There were no specific reserves related to TDRs as of December 31, 2016 , and there were $758,000 in specific reserves related to TDRs as of December 31, 2015 . The following table presents a summary of loans that were restructured during the years ended December 31, 2016 , 2015 , and 2014 . 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 Year Ended December 31, 2016 Office, retail, and industrial 1 $ 5,460 $ — $ — $ 1,083 $ 4,377 Other commercial real estate 1 745 — — — 745 Total loans restructured during the period 2 $ 6,205 $ — $ — $ 1,083 $ 5,122 Year Ended December 31, 2015 Home equity 1 120 — — — 120 1-4 family mortgages 2 325 — — — 325 Total loans restructured during the period 3 $ 445 $ — $ — $ — $ 445 Year Ended December 31, 2014 Commercial and industrial 7 $ 23,852 $ — $ — $ — $ 23,852 Office, retail, and industrial 1 417 — — — 417 Multi-family 1 275 — — — 275 Home equity 1 75 — — — 75 Total loans restructured during the period 10 $ 24,619 $ — $ — $ — $ 24,619 Accruing TDRs that do not perform in accordance with their modified terms are transferred to non-accrual. The following table presents TDRs that had payment defaults during the years ended December 31, 2016 , 2015 , and 2014 where the default occurred within twelve months of the restructure date. TDRs That Defaulted Within Twelve Months of the Restructured Date (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial and industrial — $ — — $ — 2 $ 125 Home equity 1 119 — — 1 77 Total 1 $ 119 — $ — 3 $ 202 A rollforward of the carrying value of TDRs for the years ended December 31, 2016 , 2015 , and 2014 is presented in the following table. TDR Rollforward (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Accruing Beginning balance $ 2,743 $ 3,704 $ 23,770 Additions — 120 804 Net payments (120 ) (774 ) (1,440 ) Returned to performing status — — (20,656 ) Net transfers (to) from non-accrual (332 ) (307 ) 1,226 Ending balance 2,291 2,743 3,704 Non-accrual Beginning balance 2,324 19,904 4,083 Additions 6,205 325 23,815 Net (payments) advances (1,072 ) (15,525 ) 1,991 Charge-offs (1,492 ) (2,687 ) (8,457 ) Transfers to OREO — — (302 ) Loans sold — — — Net transfers from (to) accruing 332 307 (1,226 ) Ending balance 6,297 2,324 19,904 Total TDRs $ 8,588 $ 5,067 $ 23,608 For TDRs 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 TDRs as of December 31, 2016 and 2015 .

Premises, Furniture, and Equipm

Premises, Furniture, and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Premises, Furniture, and Equipment	PREMISES, FURNITURE, AND EQUIPMENT The following table summarizes the Company's premises, furniture, and equipment by category. Premises, Furniture, and Equipment (Dollar amounts in thousands) As of December 31, 2016 2015 Land $ 18,304 $ 43,442 Premises 94,369 152,444 Furniture and equipment 105,859 90,672 Total cost 218,532 286,558 Accumulated depreciation (140,030 ) (171,708 ) Net book value of premises, furniture, and equipment 78,502 114,850 Assets held-for-sale 4,075 7,428 Premises, furniture, and equipment, net $ 82,577 $ 122,278 On September 27, 2016, the Bank completed a sale-leaseback transaction, whereby the Bank sold to a third-party for an aggregate cash purchase price of $150.3 million , 55 properties with book values totaling $58.8 million , owned and operated by the Bank as branches. Upon the sale of the branches the Bank concurrently entered into triple net lease agreements with certain affiliates of the third-party for each of the branches sold. Subject to the right of the Bank to terminate certain of the lease agreements at the end of the eleventh year, the lease agreements have initial terms of 14 years. Each lease agreement provides the Bank with five consecutive renewal options of five years each. The sale-leaseback transaction resulted in a pre-tax gain of $88.0 million , net of transaction related expenses, of which $5.5 million was immediately recognized in earnings. The remaining pre-tax gain of $82.5 million was deferred and will be accreted into income on a straight-line basis over the initial terms of the leases. Accretion related to the deferred gain of $1.5 million was recognized in 2016 and is included in net occupancy and equipment expense in the Consolidated Statement of Income. Aggregate first year rent expense to be paid under the sale-leaseback transaction is approximately $10.5 million with a 1.50% annual rent escalation during the initial term and during the first and second five-year renewal periods. As of December 31, 2016 and 2015, assets held-for-sale consisted of former branches that are no longer in operation and parcels of land previously purchased for expansion. Depreciation on premises, furniture, and equipment totaled $12.8 million in 2016 , $13.4 million in 2015 , and $12.2 million in 2014 . Operating Leases As of December 31, 2016 , the Company was obligated to utilize certain premises and equipment under certain non-cancelable operating leases, which expire at various dates through the year ending December 31, 2033 . Many of these leases contain renewal options and certain leases provide options to purchase the leased property during or at the expiration of the lease period at specific prices. Some leases contain escalation clauses calling for rentals to be adjusted for increased real estate taxes and other operating expenses or proportionately adjusted for increases in consumer or other price indices. The following summary reflects the future minimum payments by year required under operating leases that have initial or remaining non-cancelable lease terms in excess of one year as of December 31, 2016 . Future Minimum Operating Lease Payments (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 18,229 2018 16,650 2019 16,173 2020 15,580 2021 15,551 2022 and thereafter 145,095 Total minimum lease payments $ 227,278 Deferred pre-tax gains of $82.5 million related to the sale-lease back transaction will be accreted as a reduction to lease expense in other expenses on the Condensed Consolidated Statements of Income on a straight-line basis over the initial terms of the leases. The Company assumed certain operating leases related to various branches in a 2014 acquisition. On the date of acquisition, an intangible liability of $10.6 million was recorded as the cash flows of the leases exceeded the fair market value. This intangible liability is accreted into income as a reduction to net occupancy and equipment expense using the straight-line method over the initial term of each lease, which expire between 2018 to 2030. The intangible liability is included in accrued interest and other liabilities in the Consolidated Statements of Financial Condition. The following table presents the remaining scheduled accretion of the intangible liability by year. Scheduled Accretion of Operating Lease Intangible (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 1,180 2018 935 2019 685 2020 648 2021 648 2022 and thereafter 3,997 Total accretion $ 8,093 The following table presents net operating lease expense for the years ended December 31, 2016 , 2015 , and 2014 . Net Operating Lease Expense (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Lease expense charged to operations $ 11,207 $ 6,850 $ 4,669 Accretion of operating lease intangible (1) (1,171 ) (1,144 ) (453 ) Accretion of deferred gain on sale-leaseback transaction (1) (1,473 ) — — Rental income from premises leased to others (1) (527 ) (606 ) (541 ) Net operating lease expense $ 8,036 $ 5,100 $ 3,675 (1) Included as reductions to net occupancy and equipment expense in the Consolidated Statements of Income.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS The Company's annual goodwill impairment test was performed as of October 1, 2016 . It was determined that no impairment existed as of that date or as of December 31, 2016 . For a discussion of the accounting policies for goodwill and other intangible assets, see Note 1 , " Summary of Significant Accounting Policies ." The following table presents changes in the carrying amount of goodwill for the years ended December 31, 2016 , 2015 , and 2014 . Changes in the Carrying Amount of Goodwill (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 319,007 $ 310,589 $ 264,062 Acquisitions 21,872 8,418 46,527 Ending balance $ 340,879 $ 319,007 $ 310,589 The increase in goodwill for the year ended December 31, 2016 resulted from the NI Bancshares acquisition and measurement period adjustments related to finalizing the fair values of the assets acquired and liabilities assumed in the Peoples acquisition. During the year ended December 31, 2015, the increase in goodwill resulted from the Peoples acquisition and a measurement period adjustment related to finalizing the fair values of the assets acquired and liabilities assumed in the Great Lakes Financial Resources, Inc. ("Great Lakes") acquisition. During the year ended December 31, 2014, the increase in goodwill resulted from the Popular Community Bank ("Popular") and Great Lakes acquisitions. See Note 3 , " Acquisitions ," for additional detail regarding transactions completed in 2016 and 2015. The Company's other intangible assets are core deposit intangibles, which are being amortized over their estimated useful lives. Other intangible assets are subject to impairment testing when events or circumstances indicate that its carrying amount may not be recoverable. During 2016 there were no events or circumstances to indicate impairment. Other Intangible Assets (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Gross Accumulated Amortization Net Beginning balance $ 48,550 $ 28,280 $ 20,270 $ 47,970 $ 24,360 $ 23,610 $ 33,775 $ 21,471 $ 12,304 Additions 10,409 — 10,409 580 — 580 14,195 — 14,195 Amortization expense — 4,682 (4,682 ) — 3,920 (3,920 ) — 2,889 (2,889 ) Ending balance $ 58,959 $ 32,962 $ 25,997 $ 48,550 $ 28,280 $ 20,270 $ 47,970 $ 24,360 $ 23,610 Weighted-average remaining life (in years) 7.6 7.4 8.0 Estimated remaining useful lives (in years) 0.6 to 9.3 0.8 to 10.0 0.3 to 10.3 Scheduled Amortization of Other Intangible Assets (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 4,161 2018 3,237 2019 3,172 2020 3,121 2021 3,045 2022 and thereafter 9,261 Total $ 25,997

Deposits

Deposits	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Deposits	DEPOSITS The following table presents the Company's deposits by type. Summary of Deposits (Dollar amounts in thousands) As of December 31, 2016 2015 Demand deposits $ 2,766,748 $ 2,414,454 Savings deposits 1,615,833 1,547,587 NOW accounts 1,675,421 1,456,175 Money market deposits 1,577,316 1,526,056 Time deposits less than $100,000 755,558 754,576 Time deposits greater than $100,000 437,727 398,890 Total deposits $ 8,828,603 $ 8,097,738 The following table provides maturity information related to the Company's time deposits. Scheduled Maturities of Time Deposits (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 679,232 2018 167,265 2019 106,690 2020 118,347 2021 121,385 2022 and thereafter 366 Total $ 1,193,285

Borrowed Funds

Borrowed Funds	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Borrowed Funds	BORROWED FUNDS The following table summarizes the Company's borrowed funds by funding source. Summary of Borrowed Funds (Dollar amounts in thousands) As of December 31, 2016 2015 Securities sold under agreements to repurchase $ 129,008 $ 155,196 FHLB advances 750,000 9,900 Total borrowed funds $ 879,008 $ 165,096 Securities sold under agreements to repurchase are treated as financings and the obligations to repurchase securities sold are included as a liability in the Consolidated Statements of Financial Condition. Repurchase agreements are secured by U.S. treasury and agency securities which are held in third-party pledge accounts, if required. The securities underlying the agreements remain in the respective asset accounts. As of December 31, 2016 , the Company did not have amounts at risk under repurchase agreements with any individual counterparty or group of counterparties that exceeded 10% of stockholders' equity. The Bank is a member of the FHLB and has access to term financing from the FHLB. These advances are secured by designated assets that may include qualifying commercial real estate, residential and multi-family mortgages, home equity loans, and certain municipal and mortgage-backed securities. As of December 31, 2016 , FHLB advances had fixed interest rates that range from 0.49% to 0.70% and maturity dates that range from January 9, 2017 to March 1, 2017. The Company hedges interest rates on borrowed funds using interest rate swaps through which the Company receives variable amounts and pays fixed amounts. See Note 20 " Derivative Instruments and Hedging Activities " for a detailed discussion of interest rate swaps. The following table presents short-term credit lines available for use, for which the Company did not have an outstanding balance as of December 31, 2016 and 2015 . Short-Term Credit Lines Available for Use (Dollar amounts in thousands) As of December 31, 2016 2015 FRBs Discount Window Primary Credit Program $ 629,699 $ 655,745 Available federal funds lines 632,000 659,000 Correspondent bank line of credit 50,000 — On September 27, 2016, the Company entered into a loan agreement with U.S. Bank National Association providing for a $50.0 million short-term, unsecured revolving credit facility. Advances will bear interest at a rate equal to one-month LIBOR plus 1.75% , adjusted on a monthly basis, and the Company must pay an unused facility fee equal to 0.35% per annum on a quarterly basis. The line of credit will mature on September 26, 2017. Management expects to use this line of credit for general corporate purposes. As of December 31, 2016 , no amount was outstanding under the facility. None of the Company's borrowings have any related compensating balance requirements that restrict the use of Company assets.

Senior and Subordinated Debt

Senior and Subordinated Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Senior and Subordinated Debt	SENIOR AND SUBORDINATED DEBT The following table presents the Company's senior and subordinated debt by issuance. Senior and Subordinated Debt (Dollar amounts in thousands) As of December 31, Issuance Date Maturity Date Interest Rate 2016 2015 Senior notes November 2011 November 2016 5.875% $ — $ 114,891 Subordinated notes: Due in 2026 September 2016 September 2026 5.875% 146,573 — Due in 2016 March 2006 April 2016 5.850% — 38,499 Junior subordinated debentures: First Midwest Capital Trust I ("FMCT") November 2003 December 2033 6.950% 37,800 37,799 Great Lakes Statutory Trust II ("GLST II") (1) December 2005 December 2035 L+1.400% (2) 4,391 4,296 Great Lakes Statutory Trust III ("GLST III") (1) June 2007 September 2037 L+1.700% (2) 5,839 5,723 Total junior subordinated debentures 48,030 47,818 Total senior and subordinated debt $ 194,603 $ 201,208 (1) The junior subordinated debentures related to GLST II and GLST III were assumed by the Company through the Great Lakes acquisition. As of December 31, 2016, these amounts include acquisition adjustments which resulted in a discount of $1.8 million to GLST II and $2.4 million to GLST III. The acquisition adjustments totaled $1.9 million and $2.5 million to GLST II and GLST III, respectively, as of December 31, 2015. (2) The interest rates are a variable rate based on the three-month LIBOR plus 1.400% and 1.700% for GLST II and GLST III, respectively. On April 1, 2016, the $38.5 million of 5.850% subordinated notes matured and were repaid by the Company. On November 22, 2016, $115.0 million of 5.875% senior notes matured and were repaid by the Company. Issuance of Subordinated Notes On September 29, 2016, the Company completed the issuance and sale of $150.0 million aggregate principal amount of its 5.875% subordinated notes due 2026. Interest on the notes is payable semi-annually on March 29 and September 29, beginning on March 29, 2017. The Company received proceeds of $146.5 million , net of underwriting discounts and commissions and issuance costs. The Company used the net proceeds to repay at maturity the entire $115.0 million aggregate principal amount of its 5.875% senior notes on November 22, 2016, plus accrued interest, and for other general corporate purposes. Junior Subordinated Debentures FMCT, GLST II and GLST III are Delaware statutory business trusts. These trusts were established for the purpose of issuing trust-preferred securities and lending the proceeds to the Company in return for junior subordinated debentures of the Company. The junior subordinated debentures are the sole assets of each trust. Therefore, each trust's ability to pay amounts due on the trust-preferred securities is solely dependent on the Company making payments on the related junior subordinated debentures. The trust-preferred securities are subject to mandatory redemption, in whole or in part, on repayment of the junior subordinated debentures at the stated maturity date or on redemption. The Company guarantees payments of distributions and redemptions on the trust-preferred securities on a limited basis. Trust-preferred securities are included in Tier 1 capital of the Company for regulatory capital purposes. The statutory trusts qualify as VIEs for which the Company is not the primary beneficiary. Consequently, the accounts of those entities are not consolidated in the Company's financial statements.

Material Transactions Affecting

Material Transactions Affecting Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Material Transactions Affecting Stockholders' Equity	MATERIAL TRANSACTIONS AFFECTING STOCKHOLDERS' EQUITY Issued Common Stock On March 8, 2016, the Company issued 3,042,494 shares of its $0.01 par value common stock at a price of $18.059 as part of the consideration in the NI Bancshares acquisition. Additional information regarding the NI Bancshares acquisition is presented in Note 3 , " Acquisitions ." On December 2, 2014, the Company issued 2,440,754 shares of its $0.01 par value common stock at a price of $15.737 as part of the consideration in the Great Lakes acquisition. Authorized Common Stock On May 21, 2014 , the stockholders of the Company approved an amendment to the Company's Restated Certificate of Incorporation. The amendment increased the Company's authorized common stock by 50,000,000 shares. Following this amendment, the Company is now authorized to issue a total of 151,000,000 shares, including 1,000,000 shares of Preferred Stock, without a par value, and 150,000,000 shares of Common Stock, $0.01 par value per share. Quarterly Dividend on Common Shares The Company's Board of Directors ("the Board") declared stock dividends of $0.07 per share for the first quarter of 2014, and $0.08 per share for each of the quarters from the second quarter of 2014 through the fourth quarter of 2014. The Company increased the quarterly dividend to $0.09 per share for each of the quarters from the first quarter of 2015 through the fourth quarter of 2016. Other than share-based compensation which is disclosed in Note 17 , " Share-Based Compensation ", there were no additional material transactions that affected stockholders' equity during the three years ended December 31, 2016 . STOCKHOLDER RIGHTS PLAN On February 15, 1989, the Board adopted a Stockholder Rights Plan and entered into a corresponding Rights Agreement. Pursuant to that plan, the Company attached one right ("Right") to each outstanding share of Company common stock. As subsequently amended, under certain circumstances, each Right entitled the registered holder to purchase from the Company 1 / 100 of a share of Series A Preferred Stock for a price of $150 , subject to adjustment. The Rights Agreement expired in accordance with its terms on November 15, 2015. As a result, the Rights Agreement and the Stockholder Rights Plan are no longer effective.

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Common Share	EARNINGS PER COMMON SHARE The table below displays the calculation of basic and diluted EPS. Basic and Diluted EPS (Amounts in thousands, except per share data) Years Ended December 31, 2016 2015 2014 Net income $ 92,349 $ 82,064 $ 69,306 Net income applicable to non-vested restricted shares (1,043 ) (882 ) (836 ) Net income applicable to common shares $ 91,306 $ 81,182 $ 68,470 Weighted-average common shares outstanding: Weighted-average common shares outstanding (basic) 79,797 77,059 74,484 Dilutive effect of common stock equivalents 13 13 12 Weighted-average diluted common shares outstanding 79,810 77,072 74,496 Basic EPS $ 1.14 $ 1.05 $ 0.92 Diluted EPS 1.14 1.05 0.92 Anti-dilutive shares not included in the computation of diluted EPS (1) 494 800 1,198 (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.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Components of Income Tax Expense (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Current income tax expense (benefit): Federal $ 46,748 $ 18,524 $ 16,343 State 790 2,326 (1,388 ) Total 47,538 20,850 14,955 Deferred income tax (benefit) expense: Federal (7,786 ) 12,048 7,901 State 6,419 4,849 8,314 Total (1,367 ) 16,897 16,215 Total income tax expense $ 46,171 $ 37,747 $ 31,170 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 as well as state income taxes. State income tax expense and the related effective income 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. Components of Effective Tax Rate (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Amount % of Pretax Income Amount % of Pretax Income Amount % of Pretax Income Statutory federal income tax $ 48,482 35.0 % $ 41,934 35.0 % $ 35,167 35.0 % (Decrease) increase in income taxes resulting from: Tax-exempt income, net of interest expense disallowance (5,439 ) (3.9 ) (6,752 ) (5.6 ) (7,520 ) (7.5 ) State income tax, net of federal income tax effect 4,323 3.1 4,665 3.9 4,503 4.5 Other (1,195 ) (0.9 ) (2,100 ) (1.8 ) (980 ) (1.0 ) Total $ 46,171 33.3 % $ 37,747 31.5 % $ 31,170 31.0 % The increase in income tax expense and the effective tax rate from the years ended December 31, 2015 to 2016 was due primarily to higher pre-tax income subject to tax at statutory rates and a decrease in tax-exempt income. The increase in income tax expense and the effective tax rate from the years ended December 31, 2014 to 2015 resulted from an increase in pre-tax income subject to tax at statutory rates, partially offset by decreases in state statutory rates. As of December 31, 2016 , 2015 , and 2014 , the Company's retained earnings included an appropriation for an acquired thrift's tax bad debt reserves of approximately $2.5 million for which no provision for federal or state income taxes has been made. If, in the future, this portion of retained earnings were distributed as a result of the liquidation of the Company or its subsidiaries, federal and state income taxes would be imposed at the then applicable rates. Differences between the amounts reported in the consolidated financial statements and the tax basis of assets and liabilities result in temporary differences for which deferred tax assets and liabilities were recorded. Deferred Tax Assets and Liabilities (Dollar amounts in thousands) As of December 31, 2016 2015 Deferred tax assets: Allowance for credit losses $ 30,399 $ 26,131 Deferred gain on sale-leaseback transaction 28,133 — Unrealized losses on securities 18,320 18,328 Non-equity based compensation 6,060 3,739 Equity based compensation 5,228 5,469 OREO 4,336 2,597 Federal and state net operating loss ("NOL") carryforwards 388 7,679 Alternative minimum tax ("AMT") and other credit carryforwards 90 17,739 Property valuation adjustments — 3,003 Other 10,997 8,375 Total deferred tax assets 103,951 93,060 Deferred tax liabilities: Acquisition adjustments (13,407 ) (9,371 ) Accrued retirement benefits (6,281 ) (6,065 ) Deferred loan fees and costs (3,172 ) (2,432 ) Cancellation of indebtedness income (2,136 ) (3,204 ) Other (6,442 ) (5,039 ) Total deferred tax liabilities (31,438 ) (26,111 ) Deferred tax valuation allowance — — Net deferred tax assets 72,513 66,949 Tax effect of adjustments related to other comprehensive (loss) income 27,694 19,744 Net deferred tax assets including adjustments $ 100,207 $ 86,693 NOL carryforwards available to offset future taxable income: Federal gross NOL carryforwards, begin to expire in 2035 $ 574 $ 922 Illinois gross NOL carryforwards, begin to expire in 2027 26,342 160,016 Indiana gross NOL carryforwards, begin to expire in 2023 1,003 11,796 AMT credits — 17,739 During the year ended December 31, 2016, the Company recorded net deferred tax assets of $4.4 million related to the NI Bancshares acquisition and a measurement period adjustment related to finalizing the fair values of the assets acquired and liabilities assumed in the Peoples acquisition. Net deferred tax assets for the year ended December 31, 2015 includes $3.5 million of net deferred tax assets acquired from the Peoples acquisition and a measurement period adjustment related to finalizing the fair values of the assets acquired and liabilities assumed in the Great Lakes acquisition. During the years ended December 31, 2016 and 2015, the Company transferred certain loans into Real Estate Mortgage Investment Conduit trusts which are classified as loans in the financial statements and as securities for tax purposes. Net deferred tax assets are included in other assets in the accompanying Consolidated Statements of Financial Condition. Management believes that it is more likely than not that net deferred tax assets will be fully realized and no valuation allowance is required. Uncertainty in Income Taxes The Company files a U.S. federal income tax return and state income tax returns in various states. Income tax returns filed by the Company are no longer subject to examination by federal and state income tax authorities for years prior to 2013 . Rollforward of Unrecognized Tax Benefits (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 1,408 $ 912 $ 279 Additions for tax positions relating to the current year 640 480 635 Additions for tax positions relating to prior years — 37 — Reductions for tax positions relating to prior years (9 ) (21 ) (2 ) Ending balance $ 2,039 $ 1,408 $ 912 Interest and penalties not included above (1) : Interest expense, net of tax effect, and penalties $ 49 $ 20 $ 4 Accrued interest and penalties, net of tax effect, at end of year 73 24 4 (1) Included in income tax expense in the Consolidated Statements of Income. The Company does not anticipate that the amount of uncertain tax positions will significantly increase or decrease in the next 12 months. Included in the balance as of December 31, 2016 , 2015 , and 2014 are tax positions totaling $1.4 million , $936,000 and $597,000 , respectively, which would favorably affect the Company's effective tax rate if recognized in future periods.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS Profit Sharing Plan The Company has a defined contribution retirement savings plan (the "Profit Sharing Plan") that covers qualified employees who meet certain eligibility requirements. During 2014, the Profit Sharing Plan was amended to give qualified employees the option to increase contributions from 45% ( 15% for certain highly compensated employees) to 100% (including certain highly compensated employees) of their pre-tax base salary through salary deductions under Section 401(k) of the Internal Revenue Code. At the employees' direction, employee contributions are invested among a variety of investment alternatives. The amendment also increased the Company's matching contribution from a maximum of 2% to 4% of the eligible employee's compensation. In addition, pursuant to the amendment, the Company makes certain automatic and transition contributions. On an annual basis, the Company automatically contributes 2% of the employee's eligible compensation regardless of voluntary contributions made by the employee. Transition contributions of up to 4% were made through December 31, 2015 for certain employees who were active participants in the defined benefit retirement plan (the "Pension Plan"), which was frozen in 2013. The amendment did not change the discretionary profit sharing component of the Profit Sharing Plan, which permits the Company to distribute up to 15% of the employee's compensation. The Company's matching and transition contributions vest immediately, while the automatic and discretionary components vest over six years. Profit Sharing Plan (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Profit sharing expense (1) $ 6,171 $ 6,919 $ 6,354 Company dividends received by the Profit Sharing Plan $ 494 $ 466 $ 428 Company shares held by the Profit Sharing Plan at the end of the year: Number of shares 1,175,858 1,277,567 1,364,558 Fair value $ 29,667 $ 23,546 $ 23,348 (1) Included in retirement and other employee benefits in the Consolidated Statements of Income. Pension Plan The Company sponsors the Pension Plan which provides for retirement benefits based on years of service and compensation levels of the participants. The Pension Plan covers employees who met certain eligibility requirements and were hired before April 1, 2007, the date it was amended to eliminate new enrollment of new participants. During 2013, the Board approved an amendment to freeze benefit accruals under the Pension Plan effective on January 1, 2014. Actuarially determined pension costs are charged to current operations and included in retirement and other employee benefits in the Consolidated Statements of Income. The Company's funding policy is to contribute amounts to the Pension Plan that are sufficient to meet the minimum funding requirements of the Employee Retirement Income Security Act of 1974 plus additional amounts as the Company deems appropriate. Pension Plan Cost and Obligations (Dollar amounts in thousands) As of December 31, 2016 2015 Accumulated benefit obligation $ 68,959 $ 67,185 Change in projected benefit obligation: Beginning balance $ 67,185 $ 67,283 Service cost — — Interest cost 1,635 2,334 Settlements (3,136 ) (7,320 ) Actuarial loss 3,851 5,336 Benefits paid (576 ) (448 ) Ending balance $ 68,959 $ 67,185 Change in fair value of plan assets: Beginning balance $ 64,903 $ 72,193 Actual return on plan assets 3,998 478 Benefits paid (576 ) (448 ) Settlements (3,136 ) (7,320 ) Ending balance $ 65,189 $ 64,903 Funded status recognized in the Consolidated Statements of Financial Condition: Noncurrent liability $ (3,770 ) $ (2,282 ) Amounts recognized in accumulated other comprehensive loss: Prior service cost $ — $ — Net loss 28,483 26,481 Net amount recognized $ 28,483 $ 26,481 Actuarial losses included in accumulated other comprehensive loss as a percent of: Accumulated benefit obligation 41.3 % 39.4 % Fair value of plan assets 43.7 % 40.8 % Amounts expected to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year: Prior service cost $ — $ — Net loss 582 516 Net amount expected to be recognized $ 582 $ 516 Weighted-average assumptions at the end of the year used to determine the actuarial present value of the projected benefit obligation: Discount rate 3.86 % 3.99 % On December 31, 2015, the Company refined the calculation of the interest component of net periodic benefit expense for the Pension Plan. Previously, the Company estimated the interest cost component utilizing a single weighted-average discount rate derived from the yield curve used to measure the benefit obligation at the end of the period. Under the refined method, the Company utilized a full yield curve approach to estimate the component by applying specific spot rates along the yield curve used in the determination of the benefit obligation to the relevant projected cash flows. The Company made this change to more closely match the projected benefit cash flows and the corresponding yield curve spot rates, and to provide a more precise measurement of interest costs. This change had no impact on the measurement of the Company's total benefit obligations recorded as of December 31, 2015. The Company accounted for this change as a change in estimate that is inseparable from a change in accounting principle, and, accordingly, recognized its effect prospectively beginning in 2016. To the extent the cumulative actuarial losses included in accumulated other comprehensive loss exceed 10% of the greater of the accumulated benefit obligation or the market-related value of the Pension Plan assets, it is the Company's policy to amortize the Pension Plan's net actuarial losses into income over the average remaining life expectancy of the Pension Plan participants. Actuarial losses included in accumulated other comprehensive loss as of December 31, 2016 exceeded 10% of the accumulated benefit obligation and the fair value of Pension Plan assets. The amortization of net actuarial losses is a component of the net periodic benefit cost. Amortization of the net actuarial losses and prior service cost included in other comprehensive (loss) income is not expected to have a material impact on the Company's future results of operations, financial position, or liquidity. Net Periodic Benefit Pension Cost (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Components of net periodic benefit cost: Interest cost $ 1,635 $ 2,334 $ 2,346 Expected return on plan assets (4,057 ) (4,333 ) (4,931 ) Recognized net actuarial loss 571 367 249 Amortization of prior service cost — — — Recognized settlement loss 1,338 2,254 1,377 Net periodic (income) cost (513 ) 622 (959 ) Other changes in plan assets and benefit obligations recognized as a charge to other comprehensive (loss) income: Net loss for the period (3,911 ) (9,191 ) (10,752 ) Amortization of net loss 1,909 2,621 1,625 Total unrealized loss (2,002 ) (6,570 ) (9,127 ) Total recognized in net periodic pension cost and other comprehensive (loss) income $ (1,489 ) $ (7,192 ) $ (8,168 ) Weighted-average assumptions used to determine the net periodic cost: Discount rate 3.99 % 3.60 % 4.30 % Expected return on plan assets 6.50 % 6.50 % 7.25 % Pension Plan Asset Allocation (Dollar amounts in thousands) Percentage of Plan Assets as of December 31, Target Allocation Fair Value of Plan Assets (1) 2016 2015 Asset Category: Equity securities 50 - 60% $ 38,910 60 % 59 % Fixed income 30 - 48% 21,405 33 % 35 % Cash equivalents 2 - 10% 4,874 7 % 6 % Total $ 65,189 100 % 100 % (1) Additional information regarding the fair value of Pension Plan assets as of December 31, 2016 can be found in Note 22 , " Fair Value ." The expected long-term rate of return on Pension Plan assets represents the average rate of return expected to be earned over the period the benefits included in the benefit obligation are to be paid. In developing the expected rate of return, the Company considers long-term returns based on historical market data and projections of future returns for each asset category, as well as historical actual returns on the Pension Plan assets with the assistance of its independent actuarial consultant. Using this reference data, the Company develops a forward-looking return expectation for each asset category and a weighted-average expected long-term rate of return based on the target asset allocation. The investment objective of the Pension Plan is to maximize the return on Pension Plan assets over a long-term horizon to satisfy the Pension Plan obligations. In establishing its investment policies and asset allocation strategies, the Company considers expected returns and the volatility associated with different strategies. The policy established by the Company's Retirement Plan Committee provides for growth of capital with a moderate level of volatility by investing assets according to the target allocations stated above and reallocating those assets as needed to stay within those allocations. Investments are weighted toward publicly traded securities. Investment strategies that include alternative asset classes, such as private equity hedge funds and real estate, are generally avoided. Under the advisement of a certified investment advisor, the Committee reviews the investment policy on a quarterly basis to determine if any adjustments to the policy or investment strategy are necessary. The following table presents estimated future pension benefit payments under the Pension Plan for retirees already receiving benefits and future retirees, assuming they retire and begin receiving unreduced benefits as soon as they are eligible. Estimated Future Pension Benefit Payments (Dollar amounts in thousands) Total Year ending December 31, 2017 $ 16,009 2018 5,308 2019 5,059 2020 4,747 2021 4,646 2022-2026 18,583

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	SHARE-BASED COMPENSATION Share-Based Plans Omnibus Stock and Incentive Plan (the "Omnibus Plan") – In 1989, the Board adopted the Omnibus Plan, which allows for the grant of both incentive and non-statutory ("nonqualified") stock options, stock appreciation rights, restricted stock, restricted stock units, performance units, and performance shares to certain key employees. From the inception of the Omnibus Plan through the end of 2008, certain key employees were granted nonqualified stock options. The option exercise price is the average of the high and low price of the Company's common stock on the grant date. All options have a term of 10 years from the grant date, include reload features, and are non-transferable except to immediate family members, family trusts, or partnerships. Since 2008, the Company has granted restricted stock and restricted stock unit awards instead of nonqualified stock options to certain key employees. Both restricted stock and restricted stock unit awards vest over three years, with 50% vesting on the second anniversary of the grant date and the remaining 50% vesting on the third anniversary of the grant date, provided the employee remains employed by the Company during this period (subject to accelerated vesting in the event of a change-in-control or upon certain terminations of employment, as set forth in the applicable award agreement). The fair value of the awards is determined based on the average of the high and low price of the Company's common stock on the grant date. Since 2013, the Company has also granted performance shares to certain key employees. Recipients will earn performance shares totaling between 0% and 200% of the number of performance shares granted based on achieving certain performance metrics. Performance shares may be earned based on achieving an internal metric (core return on average tangible common equity) and an external metric (relative total shareholder return) over a three year period. Each metric is weighted at 50% of the total award opportunity. If earned, and assuming continued employment, the performance shares vest one-third at the completion of the three-year performance period and one-third at the end of the first and second years thereafter. The fair value of the performance shares that are dependent on the internal metric is determined based on the average of the high and low stock price on the grant date. An estimate is made as to the number of shares expected to vest as a result of actual performance against the internal metric to determine the amount of compensation expense to be recognized, which is re-evaluated quarterly. The fair value of the performance shares that are dependent on the external metric is determined using a Monte Carlo simulation model on the grant date assuming 100% of the shares are earned and issued. Nonemployee Directors Stock Plan (the "Directors Plan") – In 1997, the Board adopted the Directors Plan, which provides for the grant of equity awards to non-management Board members. Until 2008, only nonqualified stock options were issued under the Directors Plan. The exercise price of the options is equal to the average of the high and low price of the Company's common stock on the grant date. All options have a term of 10 years from the grant date. In 2008, the Company amended the Directors Plan to allow for the grant of restricted stock awards, among other items. The awards are restricted as to transfer, but are not restricted as to voting rights. Dividends accrue and are paid at the vesting date. Both the options and the restricted stock awards vest one year from the grant date subject to accelerated vesting in the event of retirement, death, disability, or change-in-control, as defined in the Directors Plan. Beginning in 2015, non-management members receive fully vested shares of the Company's common stock rather than restricted stock. Both the Omnibus Plan and the Directors Plan, and material amendments, were submitted to and approved by the stockholders of the Company. The Company issues treasury shares to satisfy stock option exercises and the vesting of restricted stock, restricted stock units, and performance share awards. Shares of Common Stock Available Under Share-Based Plans As of December 31, 2016 Shares Authorized Shares Available For Grant Omnibus Plan 8,631,641 1,998,949 Directors Plan 481,250 101,727 Stock Options Nonqualified Stock Option Transactions (Amounts in thousands, except per share data) Year Ended December 31, 2016 Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (1) Aggregate Intrinsic Value (2) Options outstanding beginning balance 756 $ 32.55 Expired (270 ) 33.95 Options outstanding ending balance 486 $ 31.77 0.94 $ 558 Exercisable at the end of the year 486 $ 31.77 0.94 $ 558 (1) Represents the average remaining contractual life in years. (2) Aggregate intrinsic value represents the total pre-tax intrinsic value that would have been received by the option holders if they had exercised their options on December 31, 2016 . Intrinsic value equals the difference between the Company's average of the high and low stock price on the last trading day of the year and the option exercise price, multiplied by the number of shares. This amount will fluctuate with changes in the fair value of the Company's common stock. Stock Option Valuation Assumptions – The Company estimates the fair value of stock options at the grant date using a Black-Scholes option-pricing model. No stock options were granted or exercised and no stock option award modifications were made during the three years ended December 31, 2016 . Restricted Stock, Restricted Stock Unit, and Performance Share Awards Restricted Stock, Restricted Stock Unit, and Performance Share Award Transactions (Amounts in thousands, except per share data) Year Ended December 31, 2016 Restricted Stock/Unit Awards Performance Shares Number of Shares/Units Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Non-vested awards beginning balance 908 $ 15.92 338 $ 15.19 Granted 494 17.28 126 17.28 Vested (351 ) 14.69 (31 ) 14.69 Forfeited (62 ) 16.72 (25 ) 16.72 Non-vested awards ending balance 989 $ 16.95 408 $ 15.78 In addition, non-management board members received 18,000 shares and 14,000 shares of common stock during the years ended December 31, 2016 and 2015, respectively. Other Restricted Stock, Restricted Stock Unit, and Performance Share Award Information (Amounts in thousands, except per share data) Years Ended December 31, 2016 2015 2014 Weighted-average grant date fair value of restricted stock, restricted stock unit, and performance share awards granted during the year $ 17.28 $ 16.95 $ 16.13 Total fair value of restricted stock and restricted stock unit awards vested during the year 12,231 7,615 7,546 Income tax benefit realized from the vesting/release of restricted stock and restricted stock unit awards 2,529 2,368 2,939 There were no performance shares that vested during the periods presented. No restricted stock, restricted stock unit, and performance share award modifications were made during the periods presented. Compensation Expense The Company recognizes share-based compensation expense based on the estimated fair value of the option or award at the grant or modification date. Share-based compensation expense is included in salaries and wages in the Consolidated Statements of Income. Effect of Recording Share-Based Compensation Expense (Dollar amounts in thousands) Years ended December 31, 2016 2015 2014 Total share-based compensation expense (1) $ 7,879 $ 7,242 $ 5,926 Income tax benefit 3,152 2,962 2,424 Share-based compensation expense, net of tax $ 4,727 $ 4,280 $ 3,502 Unrecognized compensation expense $ 9,990 $ 8,644 $ 6,937 Weighted-average amortization period remaining (in years) 1.3 1.4 1.3 (1) Comprised of restricted stock, restricted stock unit, and performance share awards expense.

Stockholder Rights Plan

Stockholder Rights Plan	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholder Rights Plan	MATERIAL TRANSACTIONS AFFECTING STOCKHOLDERS' EQUITY Issued Common Stock On March 8, 2016, the Company issued 3,042,494 shares of its $0.01 par value common stock at a price of $18.059 as part of the consideration in the NI Bancshares acquisition. Additional information regarding the NI Bancshares acquisition is presented in Note 3 , " Acquisitions ." On December 2, 2014, the Company issued 2,440,754 shares of its $0.01 par value common stock at a price of $15.737 as part of the consideration in the Great Lakes acquisition. Authorized Common Stock On May 21, 2014 , the stockholders of the Company approved an amendment to the Company's Restated Certificate of Incorporation. The amendment increased the Company's authorized common stock by 50,000,000 shares. Following this amendment, the Company is now authorized to issue a total of 151,000,000 shares, including 1,000,000 shares of Preferred Stock, without a par value, and 150,000,000 shares of Common Stock, $0.01 par value per share. Quarterly Dividend on Common Shares The Company's Board of Directors ("the Board") declared stock dividends of $0.07 per share for the first quarter of 2014, and $0.08 per share for each of the quarters from the second quarter of 2014 through the fourth quarter of 2014. The Company increased the quarterly dividend to $0.09 per share for each of the quarters from the first quarter of 2015 through the fourth quarter of 2016. Other than share-based compensation which is disclosed in Note 17 , " Share-Based Compensation ", there were no additional material transactions that affected stockholders' equity during the three years ended December 31, 2016 . STOCKHOLDER RIGHTS PLAN On February 15, 1989, the Board adopted a Stockholder Rights Plan and entered into a corresponding Rights Agreement. Pursuant to that plan, the Company attached one right ("Right") to each outstanding share of Company common stock. As subsequently amended, under certain circumstances, each Right entitled the registered holder to purchase from the Company 1 / 100 of a share of Series A Preferred Stock for a price of $150 , subject to adjustment. The Rights Agreement expired in accordance with its terms on November 15, 2015. As a result, the Rights Agreement and the Stockholder Rights Plan are no longer effective.

Regulatory and Capital Matters

Regulatory and Capital Matters	12 Months Ended
	Dec. 31, 2016
Banking and Thrift [Abstract]
Regulatory and Capital Matters	REGULATORY AND CAPITAL MATTERS The Company and its subsidiaries are subject to various regulatory requirements that impose restrictions on cash, loans or advances, and dividends. The Bank is also required to maintain reserves against deposits. Reserves are held either in the form of vault cash or noninterest-bearing balances maintained with the FRB and are based on the average daily balances and statutory reserve ratios prescribed by the type of deposit account. Reserve balances totaling $85.4 million as of December 31, 2016 and $66.9 million as of December 31, 2015 were maintained in accordance with these requirements. Under current Federal Reserve regulations, the Bank is limited in the amount it may loan or advance to First Midwest Bancorp, Inc. on an unconsolidated basis (the "Parent Company") and its non-bank subsidiaries. Loans or advances to a single subsidiary may not exceed 10% , and loans to all subsidiaries may not exceed 20% of the Bank's capital stock and surplus, as defined. Loans from subsidiary banks to non-bank subsidiaries, including the Parent Company, are also required to be collateralized. The principal source of cash flow for the Parent Company is dividends from the Bank. Various federal and state banking regulations and capital guidelines limit the amount of dividends that the Bank may pay to the Parent Company. Without prior regulatory approval and while maintaining its well-capitalized status, the Bank can initiate aggregate dividend payments in 2017 of $32.8 million plus its net profits for 2017 , as defined by statute, up to the date of any such dividend declaration. Future payment of dividends by the Bank depends on individual regulatory capital requirements and levels of profitability. The Company and the Bank are also subject to various capital requirements set up and administered by federal banking agencies. Under capital adequacy guidelines, the Company and the Bank must meet specific guidelines that involve quantitative measures given the risk levels of assets and certain off-balance sheet items calculated under regulatory accounting practices ("risk-weighted assets"). The capital amounts and classification are also subject to qualitative judgments by the regulators regarding components of capital and assets, risk weightings, and other factors. The Federal Reserve, the primary regulator of the Company and the Bank, establishes minimum capital requirements that must be met by member institutions. As defined in the regulations, quantitative measures established by regulation to ensure capital adequacy require the Company and the Bank to maintain minimum amounts and ratios of total capital to risk-weighted assets, Tier 1 capital to risk-weighted assets, common equity Tier 1 to risk-weighted assets, and Tier 1 capital to adjusted average assets. Failure to meet minimum capital requirements could result in actions by regulators that could have a material adverse effect on the Company's financial statements. As of December 31, 2016 , the Company and the Bank met all capital adequacy requirements. As of December 31, 2016 , the most recent regulatory notification classified the Bank as "well-capitalized" under the regulatory framework for prompt corrective action. There are no conditions or events since that notification that management believes would change the Bank's classification. The following table outlines the Company's and the Bank's measures of capital as of the dates presented and the capital guidelines established by the Federal Reserve for the Company and the Bank to be categorized as adequately capitalized and the Bank to be categorized as "well-capitalized." Summary of Regulatory Capital Ratios (Dollar amounts in thousands) Actual Adequately Capitalized To Be Well-Capitalized Under Prompt Corrective Action Provisions Capital Ratio % Capital Ratio % Capital Ratio % As of December 31, 2016 Total capital to risk-weighted assets: First Midwest Bancorp, Inc. $ 1,225,529 12.23 $ 864,176 8.625 N/A N/A First Midwest Bank 1,043,482 10.73 838,741 8.625 $ 972,454 10.00 Tier 1 capital to risk-weighted assets: First Midwest Bancorp, Inc. 991,873 9.90 663,788 6.625 N/A N/A First Midwest Bank 956,399 9.83 644,251 6.625 777,963 8.00 Common equity Tier 1 to risk-weighted assets: First Midwest Bancorp, Inc. 941,315 9.39 513,496 5.125 N/A N/A First Midwest Bank 956,399 9.83 498,383 5.125 632,095 6.50 Tier 1 capital to average assets: First Midwest Bancorp, Inc. 991,873 8.99 441,473 4.000 N/A N/A First Midwest Bank 956,399 8.76 436,560 4.000 545,700 5.00 As of December 31, 2015 Total capital to risk-weighted assets: First Midwest Bancorp, Inc. $ 968,331 11.15 $ 695,029 8.000 N/A N/A First Midwest Bank 929,167 11.02 674,380 8.000 $ 842,974 10.00 Tier 1 capital to risk-weighted assets: First Midwest Bancorp, Inc. 893,476 10.28 521,272 6.000 N/A N/A First Midwest Bank 854,322 10.13 505,785 6.000 674,380 8.00 Common equity Tier 1 to risk-weighted assets: First Midwest Bancorp, Inc. 845,640 9.73 390,954 4.500 N/A N/A First Midwest Bank 854,322 10.13 379,338 4.500 547,933 6.50 Tier 1 capital to average assets: First Midwest Bancorp, Inc. 893,476 9.40 380,043 4.000 N/A N/A First Midwest Bank 854,322 9.09 375,950 4.000 469,937 5.00 N/A – Not applicable. In July of 2013, the Federal Reserve published final rules (the "Basel III Capital Rules") that revise the regulatory capital rules to incorporate certain revisions by the Basel Committee on Banking Supervision. The phase-in period for the final rules began for the Company on January 1, 2015, with full compliance with the final rules entire requirement phased in on January 1, 2019. The Basel III Capital Rules (i) introduced a new capital measure called "Common Equity Tier 1" ("CET1"), (ii) specified that Tier 1 capital consists of CET1 and "Additional Tier 1 Capital" instruments meeting specified requirements, (iii) narrowly defined CET1 by requiring that most deductions/adjustments to regulatory capital measures be made to CET1 and not to the other components of capital, and (iv) expanded the scope of the deductions/adjustments compared to existing regulations. Bank holding companies with less than $15 billion in consolidated assets as of December 31, 2009, such as the Company, are permitted to include trust-preferred securities in Additional Tier 1 Capital on a permanent basis and without any phase-out. As of December 31, 2016 , the Company had $50.7 million of trust-preferred securities included in Tier 1 capital. When fully phased in on January 1, 2019, the Basel III Capital Rules will require the Company and the Bank to maintain the following: • A minimum ratio of CET1 to risk-weighted assets of at least 4.5% , plus a 2.5% "capital conservation buffer" (resulting in a minimum ratio of CET1 to risk-weighted assets of at least 7% upon full implementation). • A minimum ratio of Tier 1 capital to risk-weighted assets of at least 6.0% , plus the capital conservation buffer (resulting in a minimum Tier 1 capital ratio of 8.5% upon full implementation). • A minimum ratio of total capital (Tier 1 capital plus Tier 2 capital) to risk-weighted assets of at least 8.0% , plus the capital conservation buffer (resulting in a minimum total capital ratio of 10.5% upon full implementation). • A minimum leverage ratio of 4% , calculated as the ratio of Tier 1 capital to average assets. The Basel III Capital Rules also provide for a number of deductions from and adjustments to CET1 to be phased-in over a four -year period through January 1, 2019 (beginning at 40% on January 1, 2015 and an additional 20% per year thereafter). Examples of these include the requirement that mortgage servicing rights, deferred tax assets depending on future taxable income, and significant investments in non-consolidated financial entities be deducted from CET1 to the extent that any one such category exceeds 10% of CET1 or all such categories in the aggregate exceed 15% of CET1. Under prior capital standards, the effects of accumulated other comprehensive income items included in capital are excluded for the purposes of determining regulatory capital ratios. Under the Basel III Capital Rules, the effects of certain accumulated other comprehensive items are not excluded; however, the Company and the Bank made a one-time permanent election to continue to exclude these items. Finally, the Basel III Capital Rules prescribe a standardized approach for risk weightings that expand the risk-weighting categories from the previous four Basel I-derived categories ( 0% , 20% , 50% , and 100% ) to a much larger and more risk-sensitive number of categories depending on the nature of the assets, generally ranging from 0% for U.S. government and agency securities to 600% for certain equity exposures, resulting in higher risk weights for a variety of asset categories. The Company and the Bank believe they would meet all capital adequacy requirements under the Basel III Capital Rules on a fully phased-in basis as if such requirements were currently in effect as of December 31, 2016 and 2015.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 2015 Gross notional amount outstanding $ 5,958 $ 11,620 Derivative liability fair value (282 ) (643 ) Weighted-average interest rate received 2.63 % 2.25 % Weighted-average interest rate paid 5.96 % 6.36 % Weighted-average maturity (in years) 1.84 1.97 Fair value of derivative (1) $ 296 $ 665 (1) This amount represents the fair value if credit risk related contingent features were triggered. Hedge ineffectiveness is recognized in other noninterest income in the Consolidated Statements of Income. For the years ended December 31, 2016 , 2015 , and 2014 , gains or losses related to fair value hedge ineffectiveness were not material. Cash Flow Hedges As of December 31, 2016 , the Company hedged $735.0 million 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 $735.0 million 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 $325.0 million began on various dates between June of 2015 and June of 2016, and mature between June and August of 2019. The remaining forward starting interest rate swaps begin on various dates between February of 2017 and December of 2019 and mature between February of 2020 and December of 2021. These derivative contracts are designated as cash flow hedges. Cash Flow Hedges (Dollar amounts in thousands) As of December 31, 2016 2015 Gross notional amount outstanding $ 1,470,000 $ 1,220,000 Derivative asset fair value 5,402 4,787 Derivative liability fair value (7,390 ) (8,950 ) Weighted-average interest rate received 1.37 % 1.24 % Weighted-average interest rate paid 1.11 % 0.75 % Weighted-average maturity (in years) 2.83 3.91 The effective portion of gains or losses on cash flow hedges is recorded in accumulated other comprehensive loss on an after-tax basis and is subsequently reclassified to interest income or expense in the period that the forecasted hedged item impacts earnings. Hedge effectiveness is determined using a regression analysis at the inception of the hedge relationship and on an ongoing basis. For the years ended December 31, 2016 and 2015, there were no material gains or losses related to cash flow hedge ineffectiveness. As of December 31, 2016 , the Company estimates that $3.9 million will be reclassified from accumulated other comprehensive loss as an increase 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 December 31, 2016 and 2015 , 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 of $10.0 million , $4.8 million , and $2.2 million was recorded in noninterest income for the years ended December 31, 2016 , 2015 , and 2014, respectively. Other Derivative Instruments (Dollar amounts in thousands) As of December 31, 2016 2015 Gross notional amount outstanding $ 1,656,612 $ 853,385 Derivative asset fair value 13,478 11,446 Derivative liability fair value (13,478 ) (11,446 ) Fair value of derivative (1) 13,753 11,939 (1) This amount represents the fair value if credit risk related contingent factors 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 period presented. The Company had no other derivative instruments as of December 31, 2016 and 2015 . The Company does not enter into derivative transactions for purely speculative purposes. 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 December 31, 2016 and 2015 , 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 December 31, 2016 and 2015 . Fair Value of Offsetting Derivatives (Dollar amounts in thousands) As of December 31, 2016 2015 Assets Liabilities Assets Liabilities Gross amounts recognized $ 18,880 $ 21,150 $ 16,233 $ 21,039 Less: amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition (1) 18,880 21,150 16,233 21,039 Gross amounts not offset in the Consolidated Statements of Financial Condition: Offsetting derivative positions (10,889 ) (10,889 ) (4,791 ) (4,791 ) Cash collateral pledged — (10,261 ) — (16,248 ) Net credit exposure $ 7,991 $ — $ 11,442 $ — (1) Included in other assets or other liabilities in the Consolidated Statements of Financial Condition. As of December 31, 2016 and 2015 , 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 December 31, 2016 and 2015 , the Company was in compliance with these provisions.

Commitments, Guarantees, and Co

Commitments, Guarantees, and Contingent Liabilities	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 2015 Commitments to extend credit: Commercial, industrial, and agricultural $ 1,522,152 $ 1,303,056 Commercial real estate 397,423 366,250 Home equity 426,384 352,114 Other commitments (1) 214,943 203,121 Total commitments to extend credit $ 2,560,902 $ 2,224,541 Letters of credit $ 100,430 $ 100,610 Recourse on assets sold: Unpaid principal balance of loans sold $ 187,158 $ 196,389 Carrying value of recourse obligation (2) 142 87 (1) Other commitments includes installment and overdraft protection program commitments. (2) Included in other liabilities in the Consolidated Statements of Financial Condition. 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. 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 any non-performing 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 years ended December 31, 2016 or 2015 . Legal Proceedings In the ordinary course of business, there were certain legal proceedings pending against the Company and its subsidiaries as of December 31, 2016 . 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 financial position, results of operations, or cash flows.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 As of December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets: Trading securities: Money market funds $ 1,645 $ — $ — $ 2,530 $ — $ — Mutual funds 16,275 — — 14,364 — — Total trading securities 17,920 — — 16,894 — — Securities available-for-sale: U.S. treasury securities 48,541 — — 16,980 — — U.S. agency securities — 183,637 — — 86,643 — CMOs — 1,047,446 — — 687,185 — MBSs — 332,655 — — 153,530 — Municipal securities — 270,846 — — 327,570 CDOs — — 33,260 — — 31,529 Equity securities — 3,065 — — 3,199 — Total securities available-for- sale 48,541 1,837,649 33,260 16,980 1,258,127 31,529 Mortgage servicing rights ("MSRs") (1) — — 6,120 — — 1,853 Derivative assets (1) — 18,880 — — 16,233 — Liabilities: Derivative liabilities (2) $ — $ 21,150 $ — $ — $ 21,039 $ — (1) Included in other assets in the Consolidated Statements of Financial Condition. (2) 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. Trading Securities The Company's trading securities consist of diversified investment securities held in a grantor trust and are invested in money market and mutual funds. The fair value of these 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 in 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. CDOs are classified in level 3 in the fair value hierarchy. The Company estimates the fair values for each CDO using discounted cash flow analyses with the assistance of a structured credit valuation firm. This methodology is based on a credit analysis and historical financial data for each of the issuers underlying the CDOs (the "Issuers"). These estimates are highly subjective and sensitive to several significant, unobservable inputs. The cash flows for each Issuer are then discounted to present values using LIBOR plus an adjustment to reflect the impact of market factors. Finally, the discounted cash flows for each Issuer are aggregated to derive the estimated fair value for the specific CDO. The following table presents the ranges of significant, unobservable inputs calculated using the weighted average of the Issuers used by the Company as of December 31, 2016 and 2015 . Significant Unobservable Inputs Used in the Valuation of CDOs As of December 31, 2016 2015 Probability of prepayment 0.0 % - 10.9% 1.8 % - 15.1% Probability of default 16.7 % - 46.8% 19.1 % - 32.6% Loss given default 93.3 % - 98.9% 93.8 % - 97.1% Probability of deferral cure 7.6 % - 100.0% 15.2 % - 63.1% Most Issuers have the right to prepay the securities on the fifth anniversary of issuance and under other limited circumstances. To estimate prepayments, a credit analysis of each Issuer is performed to estimate its ability and likelihood to fund a prepayment. If a prepayment occurs, the Company receives cash equal to the par value for the portion of the CDO associated with that Issuer. The likelihood that an Issuer who is currently deferring payment on the securities will pay all deferred amounts and remain current thereafter is based on an analysis of the Issuer's asset quality, leverage ratios, and other measures of financial viability. The impact of changes in these key inputs could result in a significantly higher or lower fair value measurement for each CDO. The timing of the default, the magnitude of the default, and the timing and magnitude of the cure probability are directly interrelated. Defaults that occur sooner and/or are greater than anticipated have a negative impact on the valuation. In addition, a high cure probability assumption has a positive effect on the fair value, and, if a cure event takes place sooner than anticipated, the impact on the valuation is also favorable. Management monitors the valuation results of each CDO on a semi-annual basis, which includes an analysis of historical pricing trends for these types of securities, overall economic conditions (such as tracking LIBOR curves), and the performance of the Issuers' industries. Annually, management validates significant assumptions by reviewing detailed back-testing performed by the structured credit valuation firm. A rollforward of the carrying value of CDOs for the three years ended December 31, 2016 is presented in the following table. Carrying Value of CDOs (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 31,529 $ 33,774 $ 18,309 Additions — — 6,549 Change in other comprehensive (loss) income (1) 2,337 (2,030 ) 13,495 Paydowns and sales (2) (606 ) (215 ) (4,579 ) Ending balance $ 33,260 $ 31,529 $ 33,774 (1) Included in unrealized holding (losses) gains in the Consolidated Statements of Comprehensive Income. (2) During the year ended December 31, 2014, one CDO with a carrying value of $1.3 million and four CDOs totaling $2.9 million , which were acquired in the Great Lakes transaction, were sold. Mortgage Servicing Rights The Company services loans for others totaling $640.5 million and $242.9 million as of December 31, 2016 and 2015 , respectively. As of December 31, 2016 , loans serviced for others includes approximately $305.5 million of loans, the servicing of which transitioned from NI Bancshares to the Company as a result of the acquisition. These loans are owned by third-parties and are not included in the Consolidated Statements of Financial Condition. For additional information related to the NI Bancshares transaction, see Note 3 , " Acquisitions ." MSRs are recorded at fair value and are included in other assets in the Consolidated Statements of Financial Condition. The Company determines the fair value of MSRs 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 MSRs as December 31, 2016 and 2015 . Significant Unobservable Inputs Used in the Valuation of MSRs As of December 31, 2016 2015 Prepayment speed 7.7 % - 22.8% 10.1 % - 20.9% Maturity (months) 12 - 103 6 - 86 Discount rate 9.5 % - 13.0% 9.5 % - 13.0% The impact of changes in these key inputs could result in a significantly higher or lower fair value measurement for MSRs. 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 MSRs for the three years ended December 31, 2016 is presented in the following table. Carrying Value of MSRs (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 1,853 $ 1,728 $ 1,893 Additions from acquisition 3,092 — — New MSRs 1,263 342 315 Total (losses) gains included in earnings (1) : Changes in valuation inputs and assumptions 610 (11 ) (480 ) Other changes in fair value (2) (698 ) (206 ) — Ending balance $ 6,120 $ 1,853 $ 1,728 Contractual servicing fees earned during the year (1) $ 1,312 $ 546 $ 520 Total amount of loans being serviced for the benefit of others at the end of the year 640,530 242,915 220,372 (1) Included in mortgage banking income in the Consolidated Statements of Income and relate to assets still held at the end of the year. (2) Primarily represents changes in expected future cash flows over time 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 counterparties are representative of an exit price. Pension Plan Assets Although Pension Plan assets are not consolidated in the Company's Consolidated Statements of Financial Condition, they are required to be measured at fair value on an annual basis. The fair value of Pension Plan assets is presented in the following table by level in the fair value hierarchy. Annual Fair Value Measurements for Pension Plan Assets (Dollar amounts in thousands) As of December 31, 2016 As of December 31, 2015 Level 1 Level 2 Total Level 1 Level 2 Total Pension plan assets: Mutual funds (1) $ 29,071 $ — $ 29,071 $ 23,061 $ — $ 23,061 U.S. government and government agency securities 5,957 7,947 13,904 6,866 5,538 12,404 Corporate bonds — 7,010 7,010 — 9,569 9,569 Common stocks 7,526 — 7,526 11,330 — 11,330 Common trust funds — 7,678 7,678 — 8,539 8,539 Total pension plan assets $ 42,554 $ 22,635 $ 65,189 $ 41,257 $ 23,646 $ 64,903 (1) Includes mutual funds, money market funds, cash, cash equivalents, and accrued interest. Mutual funds, certain U.S. government agency securities, and common stocks are based on quoted market prices in active exchange markets and classified in level 1 of the fair value hierarchy. Corporate bonds and certain U.S. government and government agency securities are valued at quoted prices from independent sources that are based on observable market trades or observable prices for similar bonds where a price for the identical bond is not observable and, therefore, are classified in level 2 of the fair value hierarchy. Common trust funds are valued at quoted redemption values on the last business day of the Pension Plan's fiscal year and are classified in level 2 of the fair value hierarchy. There were no Pension Plan assets classified in level 3 of the fair value hierarchy. 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 December 31, 2016 As of December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Collateral-dependent impaired loans (1) $ — $ — $ 22,019 $ — $ — $ 10,519 OREO (2) — — 8,624 — — 8,581 Loans held-for-sale (3) — — 10,484 — — 14,444 Assets held-for-sale (4) — — 4,075 — — 7,428 (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 Loans held-for-sale consists of 1-4 family mortgage loans, which were originated with the intent to sell as of December 31, 2016 and 2015. 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. A commercial real estate loan is also included in loans held-for-sale as of December 31, 2015. Assets Held-for-Sale As of December 31, 2016, assets held-for-sale 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. Goodwill and Other Intangible Assets Goodwill and other intangible assets are subject to annual impairment testing, which requires a significant degree of management judgment. If the testing had resulted in impairment, the Company would have classified goodwill and other intangible assets as a level 3 non-recurring fair value measurement. Additional information regarding goodwill, other intangible assets, and impairment policies can be found in Note 1 , " Summary of Significant Accounting Policies ," and Note 9 , " Goodwill and Other Intangible Assets ." 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 December 31, 2016 As of December 31, 2015 Fair Value Hierarchy Carrying Fair Value Carrying Fair Value Assets: Cash and due from banks 1 $ 155,055 $ 155,055 $ 114,587 $ 114,587 Interest-bearing deposits in other banks 2 107,093 107,093 266,615 266,615 Securities held-to-maturity 2 22,291 18,212 23,152 20,054 FHLB and FRB stock 2 59,131 59,131 39,306 39,306 Loans 3 8,172,584 7,973,845 7,091,988 6,959,024 Investment in BOLI 3 219,746 219,746 209,601 209,601 Accrued interest receivable 3 34,384 34,384 27,847 27,847 Other interest-earning assets 3 834 834 1,982 1,982 Liabilities: Deposits 2 $ 8,828,603 $ 8,820,572 $ 8,097,738 $ 8,093,640 Borrowed funds 2 879,008 879,008 165,096 165,096 Senior and subordinated debt 2 194,603 197,888 201,208 205,726 Accrued interest payable 2 3,416 3,416 2,175 2,175 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. Short-Term Financial Assets and Liabilities – For financial instruments with a shorter-term or with no stated maturity, prevailing market rates, and limited credit risk, the carrying amounts approximate fair value. Those financial instruments include cash and due from banks, interest-bearing deposits in other banks, accrued interest receivable, and accrued interest payable. Securities Held-to-Maturity – The fair value of securities held-to-maturity is estimated using the present value of expected future cash flows of the remaining maturities of the securities. FHLB and FRB Stock – The carrying amounts approximate fair value as the stock is non-marketable. Loans – Loans includes the FDIC indemnification asset and net loans, which consists of loans held-for-investment, acquired loans, covered loans, and the allowance for loan losses. The fair value of loans is estimated using the present value of the expected future cash flows of the remaining maturities of the loans. Prepayment assumptions that consider the Company's historical experience and current economic and lending conditions were included. The discount rate was based on the LIBOR yield curve with adjustments for liquidity and credit risk inherent in the loans. Investment in BOLI – The fair value of BOLI approximates the carrying amount as both are based on each policy's respective CSV, which is the amount the Company would receive from liquidation of these investments. The CSV is derived from monthly reports provided by the managing brokers and is determined using the Company's initial insurance premium and earnings of the underlying assets, offset by management fees. Other Interest-Earning Assets – The fair value of other interest-earning assets is estimated using the present value of the expected future cash flows of the remaining maturities of the assets. Deposits – The fair values disclosed for demand deposits, savings deposits, NOW accounts, and money market deposits are equal to the amount payable on demand at the reporting date (i.e., their carrying amounts). The fair value for fixed-rate time deposits was estimated using the expected future cash flows discounted based on the LIBOR yield curve, plus or minus the spread associated with current pricing. Borrowed Funds – The fair value of FHLB advances is estimated by discounting the agreements based on maturities using the rates currently offered for FHLB advances of similar remaining maturities adjusted for prepayment penalties that would be incurred if the borrowings were paid off on the measurement date. The carrying amounts of securities sold under agreements to repurchase approximate their fair value due to their short-term nature. Senior and Subordinated Debt – The fair values of senior and subordinated notes are estimated based on quoted market prices of similar instruments. The fair values of junior subordinated debentures are estimated based on quoted market prices of comparable securities when available, or by discounting the expected future cash flows at market interest rates. Commitments to Extend Credit and Letters of Credit – The Company estimated the fair value of lending commitments outstanding to be immaterial based on (i) the limited interest rate exposure of the commitments outstanding due to their variable nature, (ii) the short-term nature of the commitment periods, (iii) termination clauses provided in the agreements, and (iv) the market rate of fees charged.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	RELATED PARTY TRANSACTIONS The Company, through the Bank, makes loans and has transactions with certain of its directors and executive officers. All of these loans and transactions were made in the ordinary course of business on substantially the same terms, including interest rates and collateral requirements, for comparable transactions with unrelated persons and did not involve more than the normal risk of collectability or present unfavorable features. For the years ended December 31, 2016 and 2015 , loans to directors and executive officers were not greater than 5% of stockholders' equity.

Condensed Parent Company Financ

Condensed Parent Company Financial Statements	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Parent Company Financial Statements	CONDENSED PARENT COMPANY FINANCIAL STATEMENTS The following represents the condensed financial statements of First Midwest Bancorp, Inc., the Parent Company. Statements of Financial Condition (Parent Company only) (Dollar amounts in thousands) As of December 31, 2016 2015 Assets Cash and due from banks $ 140,217 $ 119,693 Investments in and advances to subsidiaries 1,279,065 1,194,173 Other assets 139,060 63,337 Total assets $ 1,558,342 $ 1,377,203 Liabilities and Stockholders' Equity Senior and subordinated debt $ 194,603 $ 201,208 Accrued interest payable and other liabilities 106,659 29,727 Stockholders' equity 1,257,080 1,146,268 Total liabilities and stockholders' equity $ 1,558,342 $ 1,377,203 Statements of Income (Parent Company only) (Dollar amounts in thousands) Years ended December 31, 2016 2015 2014 Income Dividends from subsidiaries $ 86,791 $ 127,000 $ 56,881 Interest income 2,188 2,164 1,502 Securities transactions and other 215 584 6,451 Total income 89,194 129,748 64,834 Expenses Interest expense 12,477 12,545 12,062 Salaries and employee benefits 16,104 14,624 12,589 Other expenses 7,110 6,003 5,867 Total expenses 35,691 33,172 30,518 Income before income tax benefit and equity in undistributed (loss) income of subsidiaries 53,503 96,576 34,316 Income tax benefit 12,878 11,950 8,710 Income before equity in undistributed (loss) income of subsidiaries 66,381 108,526 43,026 Equity in undistributed income (loss) of subsidiaries 25,968 (26,462 ) 26,280 Net income 92,349 82,064 69,306 Net income applicable to non-vested restricted shares (1,043 ) (882 ) (836 ) Net income applicable to common shares $ 91,306 $ 81,182 $ 68,470 Statements of Cash Flows (Parent Company only) (Dollar amounts in thousands) Years ended December 31, 2016 2015 2014 Operating Activities Net income $ 92,349 $ 82,064 $ 69,306 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed (income) loss of subsidiaries (25,968 ) 26,462 (26,280 ) Depreciation of premises, furniture, and equipment 2 7 6 Net gains on sales of securities — (1 ) (5,702 ) Share-based compensation expense 7,879 7,242 5,926 Tax expense related to share-based compensation (685 ) (1,200 ) (106 ) Net (increase) decrease in other assets (75,104 ) 23,699 4,599 Net increase (decrease) in other liabilities 74,571 (17,132 ) 14,063 Net cash provided by operating activities 73,044 121,141 61,812 Investing Activities Purchases of securities available-for-sale (14 ) — — Proceeds from sales and maturities of securities available-for-sale 601 310 8,540 Purchase of premises, furniture, and equipment — (5 ) — Net cash paid for acquisitions (14,905 ) (16,047 ) (15,809 ) Net cash used in investing activities (14,318 ) (15,742 ) (7,269 ) Financing Activities Net proceeds from the issuance of subordinated debt 146,484 — — Payments for the retirement of senior and subordinated debt (153,500 ) — — Treasury stock activity — (120 ) 369 Cash dividends paid (29,198 ) (27,036 ) (22,568 ) Restricted stock activity (2,476 ) (2,890 ) (2,781 ) Excess tax benefit related to share-based compensation 488 794 912 Net cash used in financing activities (38,202 ) (29,252 ) (24,068 ) Net increase in cash and cash equivalents 20,524 76,147 30,475 Cash and cash equivalents at beginning of year 119,693 43,546 13,071 Cash and cash equivalents at end of year $ 140,217 $ 119,693 $ 43,546 Supplemental Disclosures of Cash Flow Information: Common stock issued for acquisitions, net of issuance costs $ 54,896 $ — $ 38,300

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS On January 6, 2017 , the Company completed the acquisition of Standard, and all operating systems were converted in the first quarter of 2017. Pursuant to the terms of the merger agreement, on January 6, 2017, each outstanding share of Standard common stock was cancelled and converted into the right to receive 0.4350 of a share of First Midwest common stock. Based on the closing trading price of shares of First Midwest common stock on the NASDAQ on that date, of $25.34 , 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 was cancelled 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 $580.5 million , which consisted of 21,057,085 shares of Company common stock and $47.1 million in cash. The following table presents the assets acquired and liabilities assumed, net of preliminary fair value adjustments, in the Standard transaction as of the acquisition date. The assets acquired and liabilities assumed, both tangible and intangible, are presented at their estimated fair values as of the acquisition date and have been accounted for under the acquisition method of accounting. These fair value adjustments, including goodwill, are preliminary based on estimates and are subject to change as more information becomes available and after final analyses of the fair values of both tangible and intangible assets acquired and liabilities assumed are completed. Goodwill recorded in the acquisition, which reflects the increased Company presence in southern metropolitan Chicago and northwest Indiana and related synergies expected from the combined operations, is not tax deductible. Acquisition Activity (Dollar amounts in thousands, except share and per share data) Standard January 6, 2017 Assets Cash and due from banks and interest-bearing deposits in other banks $ 101,944 Securities available-for-sale 214,098 FHLB and FRB stock 3,247 Loans 1,795,562 OREO 9,223 Investment in BOLI 55,629 Goodwill 328,296 Other intangible assets 25,868 Premises, furniture, and equipment 56,253 Accrued interest receivable and other assets 48,707 Total assets $ 2,638,827 Liabilities Noninterest-bearing deposits $ 676,295 Interest-bearing deposits 1,347,760 Total deposits 2,024,055 Accrued interest payable and other liabilities 34,289 Total liabilities 2,058,344 Consideration Paid Common stock (21,057,085 shares issued at $25.34 per share), net of issuance costs 533,358 Cash paid 47,125 Total consideration paid 580,483 $ 2,638,827 The Company determined that it was not practicable to disclose the further detail related to acquired loans as of the acquisition date as the fair value adjustments are preliminary based on estimates discussed above. The unaudited pro forma combined results of operations for the for the year ended December 31, 2016 is presented as if the Standard acquisition had occurred on January 1, 2016, the first day of the Company's 2016 fiscal year. The unaudited pro forma combined results of operations is presented for illustrative purposes only and does not necessarily indicate the financial results of the combined companies had the companies actually been combined at the beginning of the period presented. Fair value adjustments included in the following table are preliminary and may be revised. The unaudited pro forma results of operations also does not consider any potential impacts of potential revenue enhancements, anticipated cost savings and expense efficiencies, or asset dispositions, among other factors. Acquisition and integration related expenses directly attributable to the Standard acquisition have been excluded from the following table and are estimated to total $27.0 million , of which $8.0 million was expensed during the year ended December 31, 2016. Unaudited Pro Forma Combined Results of Operations (Dollar amounts in thousands, except per share data) For the Year Ended December 31, 2016 Total revenues (1) $ 616,922 Net income 108,770 (1) Includes net interest income and total noninterest income.

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations – First Midwest Bancorp, Inc. (the "Company") is a bank holding company that was incorporated in Delaware in 1982 and began operations on March 31, 1983. The Company is headquartered in Itasca, Illinois and has operations located primarily throughout the Chicago metropolitan area, as well as northwest Indiana, central and western Illinois, and eastern Iowa. The Company operates three wholly-owned subsidiaries: First Midwest Bank (the "Bank"), Catalyst Asset Holdings, LLC ("Catalyst"), and Parasol Investment Management, LLC ("Parasol"). The Bank conducts the majority of the Company's operations. Catalyst manages certain non-performing assets of the Company. Parasol serves in an advisory capacity to certain wealth management accounts with the Bank. The Company is engaged in commercial and retail banking and offers a broad range of banking, treasury, and wealth management products and services, tailored to the needs of its commercial and industrial, commercial real estate, municipal, and consumer customers. Basis of Presentation – 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 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.
Segment Disclosures	Segment Disclosures – The Company has one reportable segment. The Company's chief operating decision maker evaluates the operations of the Company using consolidated information for purposes of allocating resources and assessing performance. Therefore, segment disclosures are not required.
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 Consolidated Statements of Income from the effective date of the acquisition.
Cash and Cash Equivalents	Cash and Cash Equivalents – For purposes of the Consolidated Statements of Cash Flows, management defines cash and cash equivalents to include cash and due from banks, interest-bearing deposits in other banks, and other short-term investments, if any, such as federal funds sold and securities purchased under agreements to resell.
Securities	Securities – Securities are classified as held-to-maturity, trading, or available-for-sale at the time of purchase. Securities Held-to-Maturity – Securities classified as held-to-maturity are securities for which management has the intent and ability to hold to maturity. These securities are stated at cost and adjusted for amortization of premiums and accretion of discounts over the estimated lives of the securities using the effective interest method. Trading Securities – The Company's trading securities consist of diversified investment securities held in a grantor trust under deferred compensation arrangements in which plan participants may direct amounts earned to be invested in securities other than Company stock. The accounts of the grantor trust are consolidated with the accounts of the Company in its consolidated financial statements. Trading securities are reported at fair value. Other than the securities held in the grantor trust, the Company does not carry any securities for trading purposes. Securities Available-for-Sale – All other securities are classified as available-for-sale. Securities available-for-sale are carried at fair value with unrealized gains and losses, net of related deferred income taxes, recorded in stockholders' equity as a separate component of accumulated other comprehensive loss. The historical cost of debt securities is adjusted for amortization of premiums and accretion of discounts over the estimated life of the security using the effective interest method. Amortization of premiums and accretion of discounts are included in interest income. Purchases and sales of securities are recognized on a trade date basis. Realized securities gains or losses are reported in net securities gains in the Consolidated Statements of Income. The cost of securities sold is based on the specific identification method. On a quarterly basis, the Company individually assesses securities with unrealized losses to determine whether there were any events or circumstances indicating that an other-than-temporary impairment ("OTTI") has occurred. In evaluating OTTI, the Company considers many factors, including (i) the severity and duration of the impairment, (ii) the financial condition and near-term prospects of the issuer, including external credit ratings and recent downgrades for debt securities, (iii) its intent to hold the security until its value recovers, and (iv) the likelihood that it will be required to sell the security before a recovery in value, which may be at maturity. If management intends to sell the security or believes it is more likely than not that it will be required to sell the security prior to full recovery, an OTTI charge will be recognized through income as a realized loss and included in net securities gains in the Consolidated Statements of Income. If management does not expect to sell the security or believes it is not more likely than not that it will be required to sell the security prior to full recovery, the OTTI is separated into the amount related to credit deterioration, which is recognized through income as a realized loss, and the amount resulting from other factors, which is recognized in other comprehensive (loss) income.
FHLB and FRB Stock	FHLB and FRB Stock – The Company, as a member of the FHLB and FRB, is required to maintain an investment in the capital stock of the FHLB and FRB. No ready market exists for these stocks, and they have no quoted market values. The stock is redeemable at par by the FHLB and FRB and is, therefore, carried at cost and periodically evaluated for impairment.
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 consist of loans acquired by the Company in 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. During 2015, certain covered loans were no longer covered under the FDIC Agreements, and are included in acquired loans and no longer classified as covered 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 certain smaller balance 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 ("TDRs") – 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 TDRs when the modification is short-term or results in an insignificant delay in payments. The Company's TDRs 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 TDRs 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 a TDR until it is paid in full or charged-off.
Impaired Loans	Impaired Loans – Impaired loans consist of corporate non-accrual loans and TDRs. 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 TDRs, 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	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.
OREO	OREO – OREO consists of properties acquired through foreclosure in partial or total satisfaction of defaulted loans. At initial transfer into OREO, properties are recorded at fair value, less estimated selling costs. Subsequently, OREO is carried at the lower of the cost basis or fair value, less estimated selling costs. OREO write-downs occurring at the transfer date are charged against the allowance for loan losses, establishing a new cost basis. Subsequent to the initial transfer, the carrying values of OREO may be adjusted through a valuation allowance to reflect reductions in value resulting from new appraisals, new list prices, changes in market conditions, or changes in disposition strategies. Increases in value can be recognized through a reduction in the valuation allowance, but may not exceed the established cost basis. These valuation adjustments, along with expenses related to maintenance of the properties, are included in net OREO expense in the Consolidated Statements of Income.
FDIC Indemnification Asset	FDIC Indemnification Asset – The majority of loans and OREO acquired through FDIC-assisted transactions are covered by 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 indemnification period. The FDIC indemnification asset represents the present value of expected future reimbursements from the FDIC. Since the indemnified items are covered loans and covered OREO, which are initially measured at fair value, the FDIC indemnification asset is also initially measured at fair value by discounting the expected future cash flows to be received from the FDIC. These expected future cash flows are estimated by multiplying estimated losses on covered PCI loans and covered OREO by the reimbursement rates in the FDIC Agreements. The balance of the FDIC indemnification asset is adjusted periodically to reflect changes in expected future cash flows. Decreases in estimated reimbursements from the FDIC are recorded prospectively through amortization and increases in estimated reimbursements from the FDIC are recognized by an increase in the carrying value of the indemnification asset. Payments from the FDIC for reimbursement of losses result in a reduction of the FDIC indemnification asset.
Depreciable Assets	Depreciable Assets – Premises, furniture, and equipment are stated at cost, less accumulated depreciation. Depreciation expense is determined by the straight-line method over the estimated useful lives of the assets. Useful lives range from 3 to 10 years for furniture and equipment and 25 to 40 years for premises. Leasehold improvements are amortized over the shorter of the life of the asset or the lease term. Gains on dispositions are included in other noninterest income and losses on dispositions are included in other noninterest expense in the Consolidated Statements of Income. Maintenance and repairs are charged to operating expenses as incurred, while improvements that extend the useful life of assets are capitalized and depreciated over the estimated remaining life. Certain assets, such as buildings and land, that the Company intends to sell and meets held-for-sale criteria are transferred into the held-for-sale category at the lower of their fair value, as determined by a current appraisal, or their recorded investment. Long-lived depreciable assets are evaluated periodically for impairment when events or changes in circumstances indicate the carrying amount may not be recoverable. Impairment exists when the undiscounted expected future cash flows of a long-lived asset are less than its carrying value. In that event, the Company recognizes a loss for the difference between the carrying amount and the estimated fair value of the asset based on a quoted market price, if applicable, or a discounted cash flow analysis. Impairment losses are recorded in other noninterest expense in the Consolidated Statements of Income.
BOLI	BOLI – BOLI represents life insurance policies on the lives of certain Company directors and officers for which the Company is the sole owner and beneficiary. These policies are recorded as an asset in the Consolidated Statements of Financial Condition at their cash surrender value ("CSV") or the current amount that could be realized if settled. The change in CSV and insurance proceeds received are included as a component of noninterest income in the Consolidated Statements of Income.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets – Goodwill represents the excess of the purchase price of the acquisition over the fair value of the net tangible and intangible assets acquired using the acquisition method of accounting. Goodwill is not amortized. Instead, impairment testing is conducted annually as of October 1 or more often if events or circumstances between annual tests indicate that there may be impairment. Impairment testing is performed using either a qualitative or quantitative approach at the reporting unit level. All of the Company's goodwill is allocated to First Midwest Bancorp, Inc., which is the Company's only applicable reporting unit for purposes of testing goodwill for impairment. The Company performs impairment testing using a qualitative approach to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. Qualitative factors include, but are not limited to, macroeconomic conditions, industry and market specific conditions and trends, the Company's financial performance, market capitalization, stock price, and Company-specific events relevant to the assessment. If the assessment of qualitative factors indicates that it is not more likely than not that an impairment exists, no further testing is performed; otherwise, the Company would proceed with a quantitative two-step goodwill impairment test. In the first step, the Company compares its estimate of the fair value of the reporting unit, which is based on a discounted cash flow analysis, with its carrying amount, including goodwill. If the fair value of the reporting unit exceeds its carrying amount, goodwill of the reporting unit is not impaired and the second step is not required. If necessary, the second step compares the implied fair value of the reporting unit goodwill with the carrying amount of that goodwill. The implied fair value of goodwill is determined by assigning the value of the reporting unit to all of the assets and liabilities of that unit, including any other identifiable intangible assets. An impairment loss is recognized if the carrying amount of the reporting unit goodwill exceeds the implied fair value of goodwill. Other intangible assets represent purchased assets that lack physical substance, but can be distinguished from goodwill because of contractual or other legal rights or because the asset is capable of being sold or exchanged either on its own or in combination with a related contract, asset, or liability. Identified intangible assets that have a finite useful life are amortized over that life in a manner that reflects the estimated decline in the economic value of the identified intangible asset. All of the Company's other intangible assets have finite lives and are amortized over varying periods not exceeding 13 years. Intangible assets are reviewed for impairment annually or more frequently when events or circumstances indicate that its carrying amount may not be recoverable.
Wealth Management	Wealth Management – Assets held in a fiduciary or agency capacity for customers are not included in the consolidated financial statements as they are not assets of the Company or its subsidiaries. Fee income is recognized on an accrual basis and is included as a component of noninterest income in the Consolidated Statements of Income.
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 and quarterly thereafter, 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. 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. Ineffectiveness is calculated based on the change in fair value of the hedged item compared with the change in fair value of the hedging instrument. For all types of hedges, any ineffectiveness in the hedging relationship is recognized in earnings during the period the ineffectiveness occurs.
Comprehensive Income	Comprehensive Income – Comprehensive income is the total of reported net income and other comprehensive (loss) income which includes all other revenues, expenses, gains, and losses that are not reported in net income under GAAP. The Company includes the following items, net of tax, in other comprehensive (loss) income in the Consolidated Statements of Comprehensive Income: (i) changes in unrealized gains or losses on securities available-for-sale, (ii) changes in the fair value of derivatives designated as cash flow hedges, and (iii) changes in unrecognized net pension costs related to the Company's pension plan.
Treasury Stock	Treasury Stock – Treasury stock acquired is recorded at cost and is carried as a reduction of stockholders' equity in the Consolidated Statements of Financial Condition. Treasury stock issued is valued based on the "last in, first out" inventory method. The difference between the consideration received on issuance and the carrying value is charged or credited to additional paid-in capital.
Share-Based Compensation	Share-Based Compensation – The Company recognizes share-based compensation expense based on the estimated fair value of the award at the grant or modification date over the period during which an employee is required to provide service in exchange for such award. Share-based compensation expense is included in salaries and wages in the Consolidated Statements of Income.
Income Taxes	Income Taxes – The Company files United States ("U.S.") federal income tax returns and state income tax returns in various states. The provision for income taxes is based on income in the consolidated financial statements, rather than amounts reported on the Company's income tax return. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using the enacted tax rates that are expected to apply to taxable income in years in which those temporary differences are expected to be recovered or settled. A valuation allowance is established for any deferred tax asset for which recovery or settlement is not more likely than not. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income or expense in the period that includes the enactment date.
Earnings per Common Share (EPS)	Earnings per Common Share ("EPS") – EPS is computed using the two-class method. Basic EPS is computed by dividing net income applicable to common shares by the weighted-average number of common shares outstanding during the applicable period, excluding outstanding participating securities. Participating securities include non-vested restricted stock awards and restricted stock units, which contain nonforfeitable rights to dividends or dividend equivalents. Diluted earnings per common share is computed using the weighted-average number of shares determined for the basic earnings per common share computation plus the dilutive effect of stock compensation using the treasury stock method.
Adopted Accounting Pronouncements and Accounting Pronouncements Pending Adoption	Adopted Accounting Pronouncements Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern: In August of 2014, the Financial Accounting Standards Board ("FASB") issued guidance that requires management to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued. The guidance is effective for the annual and interim periods ending after December 15, 2016. The adoption of this guidance on December 31, 2016 did not impact the Company's financial condition, results of operations, or liquidity. Amendments to Consolidation Analysis: In February of 2015, the FASB issued guidance that updates current accounting for the consolidation of certain legal entities. This guidance modifies the evaluation of whether limited partnerships and similar legal entities are variable interest entities ("VIEs") or voting interest entities, eliminates the presumption that a general partner should consolidate a limited partnership, affects the consolidation analysis of reporting entities that are involved with VIEs, and provides certain exceptions from consolidation guidance for certain reporting entities. This guidance is effective for annual and interim periods beginning after December 15, 2015. The adoption of this guidance on January 1, 2016 did not materially impact the Company's financial condition, results of operations, or liquidity. Simplifying the Presentation of Debt Issuance Costs: In April of 2015, the FASB issued guidance to clarify the presentation of debt issuance costs within the balance sheet. Additionally, the guidance requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by this amendment. The guidance is effective for annual and interim periods beginning after December 15, 2015. The adoption of this guidance on January 1, 2016 did not materially impact the Company's financial condition, results of operations, or liquidity. Accounting Pronouncements Pending Adoption Revenue from Contracts with Customers: In May of 2014, the 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 was initially effective for annual and interim reporting periods beginning on or after December 15, 2016 but was deferred to December 15, 2017, and must be applied either retrospectively or using the modified retrospective approach. Early adoption is permitted, but not before the original effective date. The Company’s revenue is comprised of net interest income on financial assets and liabilities, which are excluded from the scope of this guidance, and noninterest income. The Company expects that this guidance will change how revenue from certain revenue streams is recognized within wealth management fees but does not expect these changes to have a significant impact on the Company’s financial condition, results of operations, or liquidity. The Company continues to evaluate the impact of this guidance on other components of noninterest income. 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 changes in fair value will be recognized in net income unless the investments qualify for a new practicability exception. This guidance also requires entities to recognize changes in instrument-specific credit risk related to financial liabilities measured under the fair value option in other comprehensive income. No changes were made to the guidance for classifying and measuring investments in debt securities and loans. This guidance is effective for annual and interim periods beginning after December 15, 2017. 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. 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. During the third quarter of 2016, the Company entered into a sale-leaseback transaction that resulted in a deferred gain of $82.5 million , with $81.0 million remaining as of December 31, 2016. Upon adoption of this guidance, the remaining deferred gain 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 ." Management is evaluating the new guidance and the additional impact to the Company's financial condition, results of operations, or liquidity. Contingent Put and Call Options in Debt Instruments: In March of 2016, the FASB issued final guidance clarifying the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. Entities are required to apply the guidance to existing debt instruments (or hybrid financial instruments that are determined to have a debt host) using a modified retrospective transition method as of the period of adoption. This guidance is effective for annual and interim periods beginning after December 15, 2016. 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. Equity Method Accounting: In March of 2016, the FASB issued final guidance to simplify the equity method of accounting. The guidance eliminates the requirement to retrospectively apply equity method accounting in previous periods when an investor initially obtains significant influence over an investee. This guidance is effective for annual and interim periods beginning after December 15, 2016. 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. Accounting for Employee Share-based Payments: In March of 2016, the FASB issued guidance to simplify the accounting for employee share-based payment transactions. The guidance requires entities to recognize the income tax effects of awards in the income statement when the awards vest or are settled. In addition, the guidance allows entities to repurchase more of an employee's shares than it can under current guidance for tax withholding purposes without triggering liability accounting and to make a policy election to account for forfeitures as they occur. This guidance is effective for annual and interim reporting periods beginning on or after December 15, 2016. Early adoption is permitted. Management is evaluating the new guidance, but does not expect the adoption of this guidance will materially impact the Company's financial condition, results of operations, or liquidity. 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 new guidance and the impact to the Company's financial condition, results of operations, and 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. This guidance is effective for annual and interim reporting periods beginning on or after December 15, 2017. Early adoption is permitted. Management does not expect the adoption of this guidance will materially impact the Company's Consolidated Statement of Cash Flows. Update to Amendments to Consolidation Analysis: In October of 2016, the FASB issued guidance that changes how a single decision maker will consider its indirect interests when performing the primary beneficiary analysis under the VIE model. This guidance is effective for annual and interim periods beginning after December 15, 2016. 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. 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. This guidance is effective for annual and interim periods beginning after December 15, 2017. 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. 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. This guidance is effective for annual and interim periods beginning after December 15, 2017. 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. 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.
Pension and Other Postretirement Plans	To the extent the cumulative actuarial losses included in accumulated other comprehensive loss exceed 10% of the greater of the accumulated benefit obligation or the market-related value of the Pension Plan assets, it is the Company's policy to amortize the Pension Plan's net actuarial losses into income over the average remaining life expectancy of the Pension Plan participants. Actuarial losses included in accumulated other comprehensive loss as of December 31, 2016 exceeded 10% of the accumulated benefit obligation and the fair value of Pension Plan assets. The amortization of net actuarial losses is a component of the net periodic benefit cost. Amortization of the net actuarial losses and prior service cost included in other comprehensive (loss) income is not expected to have a material impact on the Company's future results of operations, financial position, or liquidity.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisition activity	The following table presents the assets acquired and liabilities assumed, net of the fair value adjustments, in the NI Bancshares and Peoples transactions as of the acquisition date, including measurement period adjustments. The assets acquired and liabilities assumed, both intangible and tangible, were recorded at their estimated fair values as of the acquisition date and have been accounted for under the acquisition method of accounting. Acquisition Activity (Dollar amounts in thousands, except share and per share data) NI Bancshares Peoples March 8, 2016 December 3, 2015 Assets Cash and due from banks and interest-bearing deposits in other banks $ 72,533 $ 781 Securities available-for-sale 125,843 41,492 Securities held-to-maturity 1,864 — FHLB and FRB stock 1,549 558 Loans 396,886 53,766 OREO 2,863 515 Investment in BOLI 8,384 — Goodwill 21,751 7,665 Other intangible assets 10,409 580 Premises, furniture, and equipment 19,636 2,215 Accrued interest receivable and other assets 16,558 2,941 Total assets $ 678,276 $ 110,513 Liabilities Noninterest-bearing deposits $ 130,909 $ 15,869 Interest-bearing deposits 464,012 75,944 Total deposits 594,921 91,813 Borrowed funds 2,416 1,200 Intangible liabilities 230 — Accrued interest payable and other liabilities 10,627 672 Total liabilities 608,194 93,685 Consideration Paid Common stock (2016 - 3,042,494 shares issued at $18.059 per share), net of $48,000 in issuance costs 54,896 — Cash paid 15,186 16,828 Total consideration paid 70,082 16,828 $ 678,276 $ 110,513 The following table presents the assets acquired and liabilities assumed, net of preliminary fair value adjustments, in the Standard transaction as of the acquisition date. The assets acquired and liabilities assumed, both tangible and intangible, are presented at their estimated fair values as of the acquisition date and have been accounted for under the acquisition method of accounting. These fair value adjustments, including goodwill, are preliminary based on estimates and are subject to change as more information becomes available and after final analyses of the fair values of both tangible and intangible assets acquired and liabilities assumed are completed. Goodwill recorded in the acquisition, which reflects the increased Company presence in southern metropolitan Chicago and northwest Indiana and related synergies expected from the combined operations, is not tax deductible. Acquisition Activity (Dollar amounts in thousands, except share and per share data) Standard January 6, 2017 Assets Cash and due from banks and interest-bearing deposits in other banks $ 101,944 Securities available-for-sale 214,098 FHLB and FRB stock 3,247 Loans 1,795,562 OREO 9,223 Investment in BOLI 55,629 Goodwill 328,296 Other intangible assets 25,868 Premises, furniture, and equipment 56,253 Accrued interest receivable and other assets 48,707 Total assets $ 2,638,827 Liabilities Noninterest-bearing deposits $ 676,295 Interest-bearing deposits 1,347,760 Total deposits 2,024,055 Accrued interest payable and other liabilities 34,289 Total liabilities 2,058,344 Consideration Paid Common stock (21,057,085 shares issued at $25.34 per share), net of issuance costs 533,358 Cash paid 47,125 Total consideration paid 580,483 $ 2,638,827

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 2015 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 48,581 $ 26 $ (66 ) $ 48,541 $ 17,000 $ 15 $ (35 ) $ 16,980 U.S. agency securities 183,528 519 (410 ) 183,637 86,461 351 (169 ) 86,643 Collateralized mortgage 1,064,130 969 (17,653 ) 1,047,446 695,198 1,072 (9,085 ) 687,185 Other mortgage-backed 337,139 1,395 (5,879 ) 332,655 152,481 1,920 (871 ) 153,530 Municipal securities 273,319 1,245 (3,718 ) 270,846 321,437 6,443 (310 ) 327,570 Trust-preferred collateralized debt obligations ("CDOs") 47,681 261 (14,682 ) 33,260 48,287 34 (16,792 ) 31,529 Equity securities 3,206 147 (288 ) 3,065 3,282 86 (169 ) 3,199 Total securities available-for-sale $ 1,957,584 $ 4,562 $ (42,696 ) $ 1,919,450 $ 1,324,146 $ 9,921 $ (27,431 ) $ 1,306,636 Securities Held-to-Maturity Municipal securities $ 22,291 $ — $ (4,079 ) $ 18,212 $ 23,152 $ — $ (3,098 ) $ 20,054 Trading Securities $ 17,920 $ 16,894
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 December 31, 2016 2015 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 48,581 $ 26 $ (66 ) $ 48,541 $ 17,000 $ 15 $ (35 ) $ 16,980 U.S. agency securities 183,528 519 (410 ) 183,637 86,461 351 (169 ) 86,643 Collateralized mortgage 1,064,130 969 (17,653 ) 1,047,446 695,198 1,072 (9,085 ) 687,185 Other mortgage-backed 337,139 1,395 (5,879 ) 332,655 152,481 1,920 (871 ) 153,530 Municipal securities 273,319 1,245 (3,718 ) 270,846 321,437 6,443 (310 ) 327,570 Trust-preferred collateralized debt obligations ("CDOs") 47,681 261 (14,682 ) 33,260 48,287 34 (16,792 ) 31,529 Equity securities 3,206 147 (288 ) 3,065 3,282 86 (169 ) 3,199 Total securities available-for-sale $ 1,957,584 $ 4,562 $ (42,696 ) $ 1,919,450 $ 1,324,146 $ 9,921 $ (27,431 ) $ 1,306,636 Securities Held-to-Maturity Municipal securities $ 22,291 $ — $ (4,079 ) $ 18,212 $ 23,152 $ — $ (3,098 ) $ 20,054 Trading Securities $ 17,920 $ 16,894
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 December 31, 2016 2015 Amortized Cost Gross Unrealized Fair Value Amortized Cost Gross Unrealized Fair Gains Losses Gains Losses Securities Available-for-Sale U.S. treasury securities $ 48,581 $ 26 $ (66 ) $ 48,541 $ 17,000 $ 15 $ (35 ) $ 16,980 U.S. agency securities 183,528 519 (410 ) 183,637 86,461 351 (169 ) 86,643 Collateralized mortgage 1,064,130 969 (17,653 ) 1,047,446 695,198 1,072 (9,085 ) 687,185 Other mortgage-backed 337,139 1,395 (5,879 ) 332,655 152,481 1,920 (871 ) 153,530 Municipal securities 273,319 1,245 (3,718 ) 270,846 321,437 6,443 (310 ) 327,570 Trust-preferred collateralized debt obligations ("CDOs") 47,681 261 (14,682 ) 33,260 48,287 34 (16,792 ) 31,529 Equity securities 3,206 147 (288 ) 3,065 3,282 86 (169 ) 3,199 Total securities available-for-sale $ 1,957,584 $ 4,562 $ (42,696 ) $ 1,919,450 $ 1,324,146 $ 9,921 $ (27,431 ) $ 1,306,636 Securities Held-to-Maturity Municipal securities $ 22,291 $ — $ (4,079 ) $ 18,212 $ 23,152 $ — $ (3,098 ) $ 20,054 Trading Securities $ 17,920 $ 16,894
Remaining Contractual Maturity of Securities	Remaining Contractual Maturity of Securities (Dollar amounts in thousands) As of December 31, 2016 Available-for-Sale Held-to-Maturity Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 73,669 $ 71,428 $ 2,336 $ 1,909 After one year to five years 429,166 416,112 6,834 5,583 After five years to ten years 2,592 2,513 2,975 2,431 After ten years 47,682 46,231 10,146 8,289 Securities that do not have a single contractual maturity date 1,404,475 1,383,166 — — Total $ 1,957,584 $ 1,919,450 $ 22,291 $ 18,212
Securities Available-for-Sale Gains (Losses)	The following table presents net realized gains on securities available-for-sale for the three years ended December 31, 2016. Securities Available-for-Sale Gains (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Gains on sales of securities: Gross realized gains $ 1,589 $ 2,519 $ 8,188 Gross realized losses (169 ) (146 ) (63 ) Net realized gains on sales of securities 1,420 2,373 8,125 Non-cash impairment charges: OTTI — — (28 ) Net realized gains $ 1,420 $ 2,373 $ 8,097
OTTI Recognized in Earnings	The following table presents a rollforward of life-to-date OTTI recognized in earnings related to all securities available-for-sale held by the Company for the years ended December 31, 2016 , 2015 , and 2014 . The majority of the beginning and ending balance of OTTI relates to CDOs currently held by the Company. Changes in OTTI Recognized in Earnings (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 23,345 $ 23,516 $ 32,422 OTTI included in earnings (1) : Losses on securities that previously had OTTI — — 28 Losses on securities that did not previously have OTTI — — — Reduction for securities sales (2) — (171 ) (8,934 ) Ending balance $ 23,345 $ 23,345 $ 23,516 (1) Included in net securities gains in the Consolidated Statements of Income. (2) These reductions were driven by the sale of one CMO with a carrying value of $1.3 million during the year ended December 31, 2015 and one CDO with a carrying value of $1.3 million and one municipal security with a carrying value of $357,000 during the year ended December 31, 2014
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 December 31, 2016 and 2015 . Securities in an Unrealized Loss Position (Dollar amounts in thousands) Less Than 12 Months Greater Than 12 Months Total Number of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses As of December 31, 2016 Securities Available-for-Sale U.S. treasury securities 16 $ 33,505 $ 61 $ 3,995 $ 5 $ 37,500 $ 66 U.S. agency securities 28 62,064 364 11,814 46 73,878 410 CMOs 194 523,233 10,309 411,758 7,344 934,991 17,653 MBSs 68 221,174 4,726 77,780 1,154 298,954 5,880 Municipal securities 380 133,957 3,059 29,280 659 163,237 3,718 CDOs 7 — — 30,592 14,682 30,592 14,682 Equity securities 2 404 201 2,319 86 2,723 287 Total 695 $ 974,337 $ 18,720 $ 567,538 $ 23,976 $ 1,541,875 $ 42,696 Securities Held-to-Maturity Municipal securities 14 $ — $ — $ 18,212 $ 4,079 $ 18,212 $ 4,079 As of December 31, 2015 Securities Available-for-Sale U.S. treasury securities 4 $ 7,946 $ 35 $ — $ — $ 7,946 $ 35 U.S. agency securities 10 30,620 169 — — 30,620 169 CMOs 133 309,787 3,110 257,362 5,975 567,149 9,085 MBSs 27 63,028 427 31,980 444 95,008 871 Municipal securities 68 8,135 65 24,227 245 32,362 310 CDOs 8 8,034 971 21,642 15,821 29,676 16,792 Equity securities 2 485 120 2,305 49 2,790 169 Total 252 $ 428,035 $ 4,897 $ 337,516 $ 22,534 $ 765,551 $ 27,431 Securities Held-to-Maturity Municipal securities 19 $ 20,054 $ 3,098 $ — $ — $ 20,054 $ 3,098

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [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 December 31, 2016 2015 Commercial and industrial $ 2,827,658 $ 2,524,726 Agricultural 389,496 387,440 Commercial real estate: Office, retail, and industrial 1,581,827 1,395,454 Multi-family 614,034 528,324 Construction 451,540 216,882 Other commercial real estate 979,359 931,190 Total commercial real estate 3,626,760 3,071,850 Total corporate loans 6,843,914 5,984,016 Home equity 732,604 653,468 1-4 family mortgages 416,354 355,854 Installment 237,999 137,602 Total consumer loans 1,386,957 1,146,924 Covered loans (1) 23,274 30,775 Total loans $ 8,254,145 $ 7,161,715 Deferred loan fees included in total loans $ 3,838 $ 5,191 Overdrawn demand deposits included in total loans 7,836 2,810 (1) For information on covered loans, see Note 6 , " Acquired and Covered Loans ."
Schedule of Financial Instruments Owned and Pledged as Collateral	The carrying value of loans that were pledged to secure liabilities as of December 31, 2016 and 2015 are presented below. Carrying Value of Loans Pledged (Dollar amounts in thousands) As of December 31 2016 2015 Loans pledged to secure: FHLB advances $ 3,667,202 $ 3,057,421 FRB's Discount Window Primary Credit Program 777,950 841,808 Total $ 4,445,152 $ 3,899,229
Schedule of Loans Sold	The following table presents loan sales for the years ended December 31, 2016 , 2015 , and 2014 . Loan Sales (Dollar amounts in thousands) As of December 31, 2016 2015 2014 Corporate loan sales Proceeds from sales $ 54,681 $ 31,091 $ 23,222 Less book value of loans sold 52,821 29,535 22,924 Net gain on corporate sales (1) $ 1,860 $ 1,556 $ 298 1-4 family mortgage loan sales Proceeds from sales $ 290,383 $ 185,308 $ 148,680 Less book value of loans sold 283,312 180,017 144,909 Net gain on 1-4 family mortgage sales (2) 7,071 5,291 3,771 Total net gains on loan sales $ 8,931 $ 6,847 $ 4,069 (1) Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Consolidated Statements of Income. (2) Net gains on mortgage loan sales are included in mortgage banking income in the Consolidated Statements of Income.

Acquired and Covered Loans (Tab

Acquired and Covered Loans (Tables)	12 Months Ended
	Dec. 31, 2016
Acquired Loans [Abstract]
Acquired and Covered Loans	The following table presents acquired and covered PCI and Non-PCI loans as of December 31, 2016 and 2015 . Acquired and Covered Loans (Dollar amounts in thousands) As of December 31, 2016 2015 PCI Non-PCI Total PCI Non-PCI Total Acquired loans $ 53,772 $ 613,339 $ 667,111 $ 50,286 $ 534,506 $ 584,792 Covered loans 7,895 15,379 23,274 9,919 20,856 30,775 Total acquired and covered loans $ 61,667 $ 628,718 $ 690,385 $ 60,205 $ 555,362 $ 615,567
Changes In The FDIC Indemnification Asset	Rollforwards of the carrying value of the FDIC indemnification asset for the three years ended December 31, 2016 is presented in the following table. Changes in the FDIC Indemnification Asset (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 3,903 $ 8,452 $ 16,585 Amortization (1,185 ) (1,461 ) (3,315 ) Change in expected reimbursements from the FDIC for changes in expected credit losses 330 1,313 (481 ) Net payments to (from) the FDIC 1,474 (4,401 ) (4,337 ) Ending balance $ 4,522 $ 3,903 $ 8,452
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) Years Ended December 31, 2016 2015 2014 Beginning balance $ 24,912 $ 28,244 $ 36,792 Additions 3,981 1,168 3,517 Accretion (8,063 ) (11,311 ) (12,535 ) Other (1) (1,444 ) 6,811 470 Ending balance $ 19,386 $ 24,912 $ 28,244 (1) Decreases result from the resolution of certain loans occurring earlier than anticipated while increases represent a rise in the expected future cash cash flows to be collected over the remaining estimated life of the underlying portfolio.

Past Due Loans, Allowance For40

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Tables)	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 and 2015 . 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 30-89 Days Past Due 90 Days or More Past Due Total Past Due Total Loans Non-accrual 90 Days or More Past Due, Still Accruing Interest As of December 31, 2016 Commercial and industrial $ 2,816,442 $ 6,426 $ 4,790 $ 11,216 $ 2,827,658 $ 29,938 $ 374 Agricultural 388,596 — 900 900 389,496 181 736 Commercial real estate: Office, retail, and industrial 1,563,867 5,327 12,633 17,960 1,581,827 17,277 1,129 Multi-family 612,428 858 748 1,606 614,034 311 604 Construction 450,927 332 281 613 451,540 286 — Other commercial real estate 974,406 1,307 3,646 4,953 979,359 2,892 1,526 Total commercial real estate 3,601,628 7,824 17,308 25,132 3,626,760 20,766 3,259 Total corporate loans 6,806,666 14,250 22,998 37,248 6,843,914 50,885 4,369 Home equity 726,676 3,627 2,301 5,928 732,604 4,986 17 1-4 family mortgages 412,737 2,652 965 3,617 416,354 2,939 231 Installment 236,264 1,476 259 1,735 237,999 — 259 Total consumer loans 1,375,677 7,755 3,525 11,280 1,386,957 7,925 507 Covered loans 22,097 918 259 1,177 23,274 479 133 Total loans $ 8,204,440 $ 22,923 $ 26,782 $ 49,705 $ 8,254,145 $ 59,289 $ 5,009 As of December 31, 2015 Commercial and industrial $ 2,516,197 $ 4,956 $ 3,573 $ 8,529 $ 2,524,726 $ 5,587 $ 857 Agricultural 387,109 245 86 331 387,440 355 — Commercial real estate: Office, retail, and industrial 1,386,383 2,647 6,424 9,071 1,395,454 6,875 4 Multi-family 526,625 541 1,158 1,699 528,324 796 548 Construction 216,377 — 505 505 216,882 905 — Other commercial real estate 922,531 3,575 5,084 8,659 931,190 5,611 661 Total commercial real estate 3,051,916 6,763 13,171 19,934 3,071,850 14,187 1,213 Total corporate loans 5,955,222 11,964 16,830 28,794 5,984,016 20,129 2,070 Home equity 647,175 3,247 3,046 6,293 653,468 5,310 216 1-4 family mortgages 350,980 2,680 2,194 4,874 355,854 3,416 528 Installment 136,780 753 69 822 137,602 20 69 Total consumer loans 1,134,935 6,680 5,309 11,989 1,146,924 8,746 813 Covered loans 29,808 405 562 967 30,775 555 174 Total loans $ 7,119,965 $ 19,049 $ 22,701 $ 41,750 $ 7,161,715 $ 29,430 $ 3,057
Allowance For Credit Losses On Financing Receivables	A rollforward of the allowance for credit losses by portfolio segment for the years ended December 31, 2016 , 2015 , and 2014 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 Covered Loans Reserve for Unfunded Commitments Total Allowance for Credit Losses As of December 31, 2016 Beginning balance $ 37,074 $ 13,116 $ 2,462 $ 1,440 $ 6,088 $ 11,812 $ 1,638 $ 1,225 $ 74,855 Charge-offs (9,844 ) (4,707 ) (307 ) (134 ) (2,932 ) (5,229 ) (140 ) — (23,293 ) Recoveries 2,451 337 97 56 524 1,298 — — 4,763 Net charge-offs (7,393 ) (4,370 ) (210 ) (78 ) (2,408 ) (3,931 ) (140 ) — (18,530 ) Provision for loan 11,028 8,788 1,002 2,082 4,050 4,613 (580 ) (225 ) 30,758 Ending Balance $ 40,709 $ 17,534 $ 3,254 $ 3,444 $ 7,730 $ 12,494 $ 918 $ 1,000 $ 87,083 As of December 31, 2015 Beginning balance $ 29,458 $ 10,992 $ 2,249 $ 2,297 $ 8,327 $ 12,145 $ 7,226 $ 1,816 $ 74,510 Charge-offs (15,885 ) (2,887 ) (545 ) (136 ) (2,643 ) (4,187 ) (634 ) — (26,917 ) Recoveries 2,573 467 15 350 1,993 1,183 120 — 6,701 Net charge-offs (13,312 ) (2,420 ) (530 ) 214 (650 ) (3,004 ) (514 ) — (20,216 ) Provision for loan losses and other 20,928 4,544 743 (1,071 ) (1,589 ) 2,671 (5,074 ) (591 ) 20,561 Ending balance $ 37,074 $ 13,116 $ 2,462 $ 1,440 $ 6,088 $ 11,812 $ 1,638 $ 1,225 $ 74,855 As of December 31, 2014 Beginning balance $ 30,381 $ 10,405 $ 2,017 $ 6,316 $ 10,817 $ 13,010 $ 12,559 $ 1,616 $ 87,121 Charge-offs (17,424 ) (7,345 ) (943 ) (1,052 ) (4,834 ) (7,574 ) (1,012 ) — (40,184 ) Recoveries 3,800 497 87 166 1,727 729 1,199 — 8,205 Net charge-offs (13,624 ) (6,848 ) (856 ) (886 ) (3,107 ) (6,845 ) 187 — (31,979 ) Provision for loan 12,701 7,435 1,088 (3,133 ) 617 5,980 (5,520 ) 200 19,368 Ending balance $ 29,458 $ 10,992 $ 2,249 $ 2,297 $ 8,327 $ 12,145 $ 7,226 $ 1,816 $ 74,510
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 December 31, 2016 and 2015 . 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 December 31, 2016 Commercial, industrial, and $ 24,645 $ 3,189,327 $ 3,182 $ 3,217,154 $ 507 $ 39,554 $ 648 $ 40,709 Commercial real estate: Office, retail, and industrial 16,287 1,553,234 12,306 1,581,827 — 16,148 1,386 17,534 Multi-family 398 601,429 12,207 614,034 — 3,059 195 3,254 Construction 34 447,058 4,448 451,540 — 3,280 164 3,444 Other commercial real estate 1,286 965,900 12,173 979,359 18 6,613 1,099 7,730 Total commercial real estate 18,005 3,567,621 41,134 3,626,760 18 29,100 2,844 31,962 Total corporate loans 42,650 6,756,948 44,316 6,843,914 525 68,654 3,492 72,671 Consumer — 1,377,501 9,456 1,386,957 — 12,101 393 12,494 Covered loans — 15,379 7,895 23,274 — 109 809 918 Reserve for unfunded — — — — — 1,000 — 1,000 Total loans $ 42,650 $ 8,149,828 $ 61,667 $ 8,254,145 $ 525 $ 81,864 $ 4,694 $ 87,083 As of December 31, 2015 Commercial, industrial, and $ 2,871 $ 2,902,361 $ 6,934 $ 2,912,166 $ 883 $ 35,378 $ 813 $ 37,074 Commercial real estate: Office, retail, and industrial 6,162 1,376,789 12,503 1,395,454 715 10,833 1,568 13,116 Multi-family 800 526,037 1,487 528,324 — 2,367 95 2,462 Construction 178 212,671 4,033 216,882 — 1,160 280 1,440 Other commercial real estate 3,665 913,161 14,364 931,190 — 5,367 721 6,088 Total commercial real estate 10,805 3,028,658 32,387 3,071,850 715 19,727 2,664 23,106 Total corporate loans 13,676 5,931,019 39,321 5,984,016 1,598 55,105 3,477 60,180 Consumer — 1,135,959 10,965 1,146,924 — 11,425 387 11,812 Covered loans — 20,856 9,919 30,775 — 248 1,390 1,638 Reserve for unfunded — — — — — 1,225 — 1,225 Total loans $ 13,676 $ 7,087,834 $ 60,205 $ 7,161,715 $ 1,598 $ 68,003 $ 5,254 $ 74,855
Impaired Financing Receivables	The following table presents the average recorded investment and interest income recognized on impaired loans by class for the years ended December 31, 2016 , 2015 , and 2014 . PCI loans are excluded from this disclosure. Average Recorded Investment and Interest Income Recognized on Impaired Loans by Class (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Average Recorded Investment Interest Income Recognized (1) Average Recorded Investment Interest Income Recognized (1) Average Interest (1) Commercial and industrial $ 9,178 $ 104 $ 8,940 $ 163 $ 16,137 $ 371 Agricultural — — — — — — Commercial real estate: Office, retail, and industrial 12,867 291 9,359 52 19,003 245 Multi-family 479 11 855 13 1,245 5 Construction 63 — 3,902 118 5,764 — Other commercial real estate 2,809 86 3,310 44 6,014 138 Total commercial real estate 16,218 388 17,426 227 32,026 388 Total impaired loans $ 25,396 $ 492 $ 26,366 $ 390 $ 48,163 $ 759 (1) Recorded using the cash basis of accounting. The following table presents loans individually evaluated for impairment by class of loan as of December 31, 2016 and 2015 . PCI loans are excluded from this disclosure. Impaired Loans Individually Evaluated by Class (Dollar amounts in thousands) As of December 31, 2016 2015 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 $ 11,579 $ 13,066 $ 29,514 $ 507 $ 1,673 $ 1,198 $ 4,592 $ 883 Agricultural — — — — — — — — Commercial real estate: Office, retail, and industrial 16,287 — 21,057 — 4,654 1,508 12,083 715 Multi-family 398 — 398 — 800 — 941 — Construction 34 — 34 — 178 — 299 — Other commercial real estate 1,016 270 2,141 18 3,665 — 4,403 — Total commercial real 17,735 270 23,630 18 9,297 1,508 17,726 715 Total impaired loans $ 29,314 $ 13,336 $ 53,144 $ 525 $ 10,970 $ 2,706 $ 22,318 $ 1,598
Financing Receivable Credit Quality Indicators	Consumer Credit Quality Indicators by Class, Excluding Covered Loans (Dollar amounts in thousands) Performing Non-accrual Total As of December 31, 2016 Home equity $ 727,618 $ 4,986 $ 732,604 1-4 family mortgages 413,415 2,939 416,354 Installment 237,999 — 237,999 Total consumer loans $ 1,379,032 $ 7,925 $ 1,386,957 As of December 31, 2015 Home equity $ 648,158 $ 5,310 $ 653,468 1-4 family mortgages 352,438 3,416 355,854 Installment 137,582 20 137,602 Total consumer loans $ 1,138,178 $ 8,746 $ 1,146,924 The following tables present credit quality indicators by class for corporate and consumer loans, excluding covered loans, as of December 31, 2016 and 2015 . Corporate Credit Quality Indicators by Class, Excluding Covered Loans (Dollar amounts in thousands) Pass Special (1)(4) Substandard (2)(4) Non-accrual (3) Total As of December 31, 2016 Commercial and industrial $ 2,638,833 $ 92,340 $ 66,547 $ 29,938 $ 2,827,658 Agricultural 366,382 17,039 5,894 181 389,496 Commercial real estate: Office, retail, and industrial 1,491,030 34,007 39,513 17,277 1,581,827 Multi-family 607,324 4,370 2,029 311 614,034 Construction 438,946 111 12,197 286 451,540 Other commercial real estate 951,115 11,808 13,544 2,892 979,359 Total commercial real estate 3,488,415 50,296 67,283 20,766 3,626,760 Total corporate loans $ 6,493,630 $ 159,675 $ 139,724 $ 50,885 $ 6,843,914 As of December 31, 2015 Commercial and industrial $ 2,379,992 $ 86,263 $ 52,884 $ 5,587 $ 2,524,726 Agricultural 381,523 — 5,562 355 387,440 Commercial real estate: Office, retail, and industrial 1,320,164 32,627 35,788 6,875 1,395,454 Multi-family 517,412 6,146 3,970 796 528,324 Construction 201,496 4,678 9,803 905 216,882 Other commercial real estate 898,746 13,179 13,654 5,611 931,190 Total commercial real estate 2,937,818 56,630 63,215 14,187 3,071,850 Total corporate loans $ 5,699,333 $ 142,893 $ 121,661 $ 20,129 $ 5,984,016 (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 a well-defined weakness 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 a well-defined weakness 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 TDRs of $834,000 as of December 31, 2016 and $862,000 as of December 31, 2015 .
Troubled Debt Restructurings on Financing Receivables	The table below presents TDRs by class as of December 31, 2016 and 2015 . See Note 1 , " Summary of Significant Accounting Policies ," for the accounting policy for TDRs. TDRs by Class (Dollar amounts in thousands) As of December 31, 2016 2015 Accruing Non-accrual (1) Total Accruing Non-accrual (1) Total Commercial and industrial $ 281 $ 150 $ 431 $ 294 $ 1,050 $ 1,344 Agricultural — — — — — — Commercial real estate: Office, retail, and industrial 155 4,733 4,888 164 — 164 Multi-family 586 168 754 598 186 784 Construction — — — — — — Other commercial real estate 268 48 316 340 — 340 Total commercial real estate 1,009 4,949 5,958 1,102 186 1,288 Total corporate loans 1,290 5,099 6,389 1,396 1,236 2,632 Home equity 177 820 997 494 667 1,161 1-4 family mortgages 824 378 1,202 853 421 1,274 Installment — — — — — — Total consumer loans 1,001 1,198 2,199 1,347 1,088 2,435 Total loans $ 2,291 $ 6,297 $ 8,588 $ 2,743 $ 2,324 $ 5,067 (1) These TDRs are included in non-accrual loans in the preceding tables. The following table presents a summary of loans that were restructured during the years ended December 31, 2016 , 2015 , and 2014 . 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 Year Ended December 31, 2016 Office, retail, and industrial 1 $ 5,460 $ — $ — $ 1,083 $ 4,377 Other commercial real estate 1 745 — — — 745 Total loans restructured during the period 2 $ 6,205 $ — $ — $ 1,083 $ 5,122 Year Ended December 31, 2015 Home equity 1 120 — — — 120 1-4 family mortgages 2 325 — — — 325 Total loans restructured during the period 3 $ 445 $ — $ — $ — $ 445 Year Ended December 31, 2014 Commercial and industrial 7 $ 23,852 $ — $ — $ — $ 23,852 Office, retail, and industrial 1 417 — — — 417 Multi-family 1 275 — — — 275 Home equity 1 75 — — — 75 Total loans restructured during the period 10 $ 24,619 $ — $ — $ — $ 24,619 A rollforward of the carrying value of TDRs for the years ended December 31, 2016 , 2015 , and 2014 is presented in the following table. TDR Rollforward (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Accruing Beginning balance $ 2,743 $ 3,704 $ 23,770 Additions — 120 804 Net payments (120 ) (774 ) (1,440 ) Returned to performing status — — (20,656 ) Net transfers (to) from non-accrual (332 ) (307 ) 1,226 Ending balance 2,291 2,743 3,704 Non-accrual Beginning balance 2,324 19,904 4,083 Additions 6,205 325 23,815 Net (payments) advances (1,072 ) (15,525 ) 1,991 Charge-offs (1,492 ) (2,687 ) (8,457 ) Transfers to OREO — — (302 ) Loans sold — — — Net transfers from (to) accruing 332 307 (1,226 ) Ending balance 6,297 2,324 19,904 Total TDRs $ 8,588 $ 5,067 $ 23,608 The following table presents TDRs that had payment defaults during the years ended December 31, 2016 , 2015 , and 2014 where the default occurred within twelve months of the restructure date. TDRs That Defaulted Within Twelve Months of the Restructured Date (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Number of Loans Recorded Investment Number of Loans Recorded Investment Number of Loans Recorded Investment Commercial and industrial — $ — — $ — 2 $ 125 Home equity 1 119 — — 1 77 Total 1 $ 119 — $ — 3 $ 202

Premises, Furniture, and Equi41

Premises, Furniture, and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	The following table summarizes the Company's premises, furniture, and equipment by category. Premises, Furniture, and Equipment (Dollar amounts in thousands) As of December 31, 2016 2015 Land $ 18,304 $ 43,442 Premises 94,369 152,444 Furniture and equipment 105,859 90,672 Total cost 218,532 286,558 Accumulated depreciation (140,030 ) (171,708 ) Net book value of premises, furniture, and equipment 78,502 114,850 Assets held-for-sale 4,075 7,428 Premises, furniture, and equipment, net $ 82,577 $ 122,278
Schedule of Future Minimum Lease Payments for Capital Leases	The following summary reflects the future minimum payments by year required under operating leases that have initial or remaining non-cancelable lease terms in excess of one year as of December 31, 2016 . Future Minimum Operating Lease Payments (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 18,229 2018 16,650 2019 16,173 2020 15,580 2021 15,551 2022 and thereafter 145,095 Total minimum lease payments $ 227,278
Scheduled Accretion of Operating Leases	The following table presents the remaining scheduled accretion of the intangible liability by year. Scheduled Accretion of Operating Lease Intangible (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 1,180 2018 935 2019 685 2020 648 2021 648 2022 and thereafter 3,997 Total accretion $ 8,093
Schedule Of Rental Expense And Income	The following table presents net operating lease expense for the years ended December 31, 2016 , 2015 , and 2014 . Net Operating Lease Expense (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Lease expense charged to operations $ 11,207 $ 6,850 $ 4,669 Accretion of operating lease intangible (1) (1,171 ) (1,144 ) (453 ) Accretion of deferred gain on sale-leaseback transaction (1) (1,473 ) — — Rental income from premises leased to others (1) (527 ) (606 ) (541 ) Net operating lease expense $ 8,036 $ 5,100 $ 3,675 (1) Included as reductions to net occupancy and equipment expense in the Consolidated Statements of Income.

Goodwill and Other Intangible42

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table presents changes in the carrying amount of goodwill for the years ended December 31, 2016 , 2015 , and 2014 . Changes in the Carrying Amount of Goodwill (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 319,007 $ 310,589 $ 264,062 Acquisitions 21,872 8,418 46,527 Ending balance $ 340,879 $ 319,007 $ 310,589
Schedule of Finite-Lived Intangible Assets	Other Intangible Assets (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Gross Accumulated Amortization Net Beginning balance $ 48,550 $ 28,280 $ 20,270 $ 47,970 $ 24,360 $ 23,610 $ 33,775 $ 21,471 $ 12,304 Additions 10,409 — 10,409 580 — 580 14,195 — 14,195 Amortization expense — 4,682 (4,682 ) — 3,920 (3,920 ) — 2,889 (2,889 ) Ending balance $ 58,959 $ 32,962 $ 25,997 $ 48,550 $ 28,280 $ 20,270 $ 47,970 $ 24,360 $ 23,610 Weighted-average remaining life (in years) 7.6 7.4 8.0 Estimated remaining useful lives (in years) 0.6 to 9.3 0.8 to 10.0 0.3 to 10.3
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Scheduled Amortization of Other Intangible Assets (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 4,161 2018 3,237 2019 3,172 2020 3,121 2021 3,045 2022 and thereafter 9,261 Total $ 25,997

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Schedule of Deposits	The following table presents the Company's deposits by type. Summary of Deposits (Dollar amounts in thousands) As of December 31, 2016 2015 Demand deposits $ 2,766,748 $ 2,414,454 Savings deposits 1,615,833 1,547,587 NOW accounts 1,675,421 1,456,175 Money market deposits 1,577,316 1,526,056 Time deposits less than $100,000 755,558 754,576 Time deposits greater than $100,000 437,727 398,890 Total deposits $ 8,828,603 $ 8,097,738
Schedule of Maturities of Time Deposits	The following table provides maturity information related to the Company's time deposits. Scheduled Maturities of Time Deposits (Dollar amounts in thousands) Total Year Ending December 31, 2017 $ 679,232 2018 167,265 2019 106,690 2020 118,347 2021 121,385 2022 and thereafter 366 Total $ 1,193,285

Borrowed Funds (Tables)

Borrowed Funds (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Debt	The following table summarizes the Company's borrowed funds by funding source. Summary of Borrowed Funds (Dollar amounts in thousands) As of December 31, 2016 2015 Securities sold under agreements to repurchase $ 129,008 $ 155,196 FHLB advances 750,000 9,900 Total borrowed funds $ 879,008 $ 165,096
Unused Short-Term Credit Lines Available for Use	The following table presents short-term credit lines available for use, for which the Company did not have an outstanding balance as of December 31, 2016 and 2015 . Short-Term Credit Lines Available for Use (Dollar amounts in thousands) As of December 31, 2016 2015 FRBs Discount Window Primary Credit Program $ 629,699 $ 655,745 Available federal funds lines 632,000 659,000 Correspondent bank line of credit 50,000 —

Senior and Subordinated Debt (T

Senior and Subordinated Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table presents the Company's senior and subordinated debt by issuance. Senior and Subordinated Debt (Dollar amounts in thousands) As of December 31, Issuance Date Maturity Date Interest Rate 2016 2015 Senior notes November 2011 November 2016 5.875% $ — $ 114,891 Subordinated notes: Due in 2026 September 2016 September 2026 5.875% 146,573 — Due in 2016 March 2006 April 2016 5.850% — 38,499 Junior subordinated debentures: First Midwest Capital Trust I ("FMCT") November 2003 December 2033 6.950% 37,800 37,799 Great Lakes Statutory Trust II ("GLST II") (1) December 2005 December 2035 L+1.400% (2) 4,391 4,296 Great Lakes Statutory Trust III ("GLST III") (1) June 2007 September 2037 L+1.700% (2) 5,839 5,723 Total junior subordinated debentures 48,030 47,818 Total senior and subordinated debt $ 194,603 $ 201,208 (1) The junior subordinated debentures related to GLST II and GLST III were assumed by the Company through the Great Lakes acquisition. As of December 31, 2016, these amounts include acquisition adjustments which resulted in a discount of $1.8 million to GLST II and $2.4 million to GLST III. The acquisition adjustments totaled $1.9 million and $2.5 million to GLST II and GLST III, respectively, as of December 31, 2015. (2) The interest rates are a variable rate based on the three-month LIBOR plus 1.400% and 1.700% for GLST II and GLST III, respectively.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The table below displays the calculation of basic and diluted EPS. Basic and Diluted EPS (Amounts in thousands, except per share data) Years Ended December 31, 2016 2015 2014 Net income $ 92,349 $ 82,064 $ 69,306 Net income applicable to non-vested restricted shares (1,043 ) (882 ) (836 ) Net income applicable to common shares $ 91,306 $ 81,182 $ 68,470 Weighted-average common shares outstanding: Weighted-average common shares outstanding (basic) 79,797 77,059 74,484 Dilutive effect of common stock equivalents 13 13 12 Weighted-average diluted common shares outstanding 79,810 77,072 74,496 Basic EPS $ 1.14 $ 1.05 $ 0.92 Diluted EPS 1.14 1.05 0.92 Anti-dilutive shares not included in the computation of diluted EPS (1) 494 800 1,198 (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.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Components of Income Tax Expense (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Current income tax expense (benefit): Federal $ 46,748 $ 18,524 $ 16,343 State 790 2,326 (1,388 ) Total 47,538 20,850 14,955 Deferred income tax (benefit) expense: Federal (7,786 ) 12,048 7,901 State 6,419 4,849 8,314 Total (1,367 ) 16,897 16,215 Total income tax expense $ 46,171 $ 37,747 $ 31,170
Schedule of Effective Income Tax Rate Reconciliation	Components of Effective Tax Rate (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Amount % of Pretax Income Amount % of Pretax Income Amount % of Pretax Income Statutory federal income tax $ 48,482 35.0 % $ 41,934 35.0 % $ 35,167 35.0 % (Decrease) increase in income taxes resulting from: Tax-exempt income, net of interest expense disallowance (5,439 ) (3.9 ) (6,752 ) (5.6 ) (7,520 ) (7.5 ) State income tax, net of federal income tax effect 4,323 3.1 4,665 3.9 4,503 4.5 Other (1,195 ) (0.9 ) (2,100 ) (1.8 ) (980 ) (1.0 ) Total $ 46,171 33.3 % $ 37,747 31.5 % $ 31,170 31.0 %
Schedule of Deferred Tax Assets and Liabilities	Deferred Tax Assets and Liabilities (Dollar amounts in thousands) As of December 31, 2016 2015 Deferred tax assets: Allowance for credit losses $ 30,399 $ 26,131 Deferred gain on sale-leaseback transaction 28,133 — Unrealized losses on securities 18,320 18,328 Non-equity based compensation 6,060 3,739 Equity based compensation 5,228 5,469 OREO 4,336 2,597 Federal and state net operating loss ("NOL") carryforwards 388 7,679 Alternative minimum tax ("AMT") and other credit carryforwards 90 17,739 Property valuation adjustments — 3,003 Other 10,997 8,375 Total deferred tax assets 103,951 93,060 Deferred tax liabilities: Acquisition adjustments (13,407 ) (9,371 ) Accrued retirement benefits (6,281 ) (6,065 ) Deferred loan fees and costs (3,172 ) (2,432 ) Cancellation of indebtedness income (2,136 ) (3,204 ) Other (6,442 ) (5,039 ) Total deferred tax liabilities (31,438 ) (26,111 ) Deferred tax valuation allowance — — Net deferred tax assets 72,513 66,949 Tax effect of adjustments related to other comprehensive (loss) income 27,694 19,744 Net deferred tax assets including adjustments $ 100,207 $ 86,693 NOL carryforwards available to offset future taxable income: Federal gross NOL carryforwards, begin to expire in 2035 $ 574 $ 922 Illinois gross NOL carryforwards, begin to expire in 2027 26,342 160,016 Indiana gross NOL carryforwards, begin to expire in 2023 1,003 11,796 AMT credits — 17,739
Summary of Income Tax Contingencies	Rollforward of Unrecognized Tax Benefits (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 1,408 $ 912 $ 279 Additions for tax positions relating to the current year 640 480 635 Additions for tax positions relating to prior years — 37 — Reductions for tax positions relating to prior years (9 ) (21 ) (2 ) Ending balance $ 2,039 $ 1,408 $ 912 Interest and penalties not included above (1) : Interest expense, net of tax effect, and penalties $ 49 $ 20 $ 4 Accrued interest and penalties, net of tax effect, at end of year 73 24 4 (1) Included in income tax expense in the Consolidated Statements of Income.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Profit Sharing Plan	Profit Sharing Plan (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Profit sharing expense (1) $ 6,171 $ 6,919 $ 6,354 Company dividends received by the Profit Sharing Plan $ 494 $ 466 $ 428 Company shares held by the Profit Sharing Plan at the end of the year: Number of shares 1,175,858 1,277,567 1,364,558 Fair value $ 29,667 $ 23,546 $ 23,348 (1) Included in retirement and other employee benefits in the Consolidated Statements of Income.
Schedule of Pension Plan Cost and Obligation	Pension Plan Cost and Obligations (Dollar amounts in thousands) As of December 31, 2016 2015 Accumulated benefit obligation $ 68,959 $ 67,185 Change in projected benefit obligation: Beginning balance $ 67,185 $ 67,283 Service cost — — Interest cost 1,635 2,334 Settlements (3,136 ) (7,320 ) Actuarial loss 3,851 5,336 Benefits paid (576 ) (448 ) Ending balance $ 68,959 $ 67,185 Change in fair value of plan assets: Beginning balance $ 64,903 $ 72,193 Actual return on plan assets 3,998 478 Benefits paid (576 ) (448 ) Settlements (3,136 ) (7,320 ) Ending balance $ 65,189 $ 64,903 Funded status recognized in the Consolidated Statements of Financial Condition: Noncurrent liability $ (3,770 ) $ (2,282 ) Amounts recognized in accumulated other comprehensive loss: Prior service cost $ — $ — Net loss 28,483 26,481 Net amount recognized $ 28,483 $ 26,481 Actuarial losses included in accumulated other comprehensive loss as a percent of: Accumulated benefit obligation 41.3 % 39.4 % Fair value of plan assets 43.7 % 40.8 % Amounts expected to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year: Prior service cost $ — $ — Net loss 582 516 Net amount expected to be recognized $ 582 $ 516 Weighted-average assumptions at the end of the year used to determine the actuarial present value of the projected benefit obligation: Discount rate 3.86 % 3.99 %
Schedule of Net Periodic Benefit Pension Costs	Net Periodic Benefit Pension Cost (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Components of net periodic benefit cost: Interest cost $ 1,635 $ 2,334 $ 2,346 Expected return on plan assets (4,057 ) (4,333 ) (4,931 ) Recognized net actuarial loss 571 367 249 Amortization of prior service cost — — — Recognized settlement loss 1,338 2,254 1,377 Net periodic (income) cost (513 ) 622 (959 ) Other changes in plan assets and benefit obligations recognized as a charge to other comprehensive (loss) income: Net loss for the period (3,911 ) (9,191 ) (10,752 ) Amortization of net loss 1,909 2,621 1,625 Total unrealized loss (2,002 ) (6,570 ) (9,127 ) Total recognized in net periodic pension cost and other comprehensive (loss) income $ (1,489 ) $ (7,192 ) $ (8,168 ) Weighted-average assumptions used to determine the net periodic cost: Discount rate 3.99 % 3.60 % 4.30 % Expected return on plan assets 6.50 % 6.50 % 7.25 %
Schedule of Pension Plan Asset Allocation	Pension Plan Asset Allocation (Dollar amounts in thousands) Percentage of Plan Assets as of December 31, Target Allocation Fair Value of Plan Assets (1) 2016 2015 Asset Category: Equity securities 50 - 60% $ 38,910 60 % 59 % Fixed income 30 - 48% 21,405 33 % 35 % Cash equivalents 2 - 10% 4,874 7 % 6 % Total $ 65,189 100 % 100 % (1) Additional information regarding the fair value of Pension Plan assets as of December 31, 2016 can be found in Note 22 , " Fair Value ."
Schedule of Estimated Future Pension Benefit Payments	The following table presents estimated future pension benefit payments under the Pension Plan for retirees already receiving benefits and future retirees, assuming they retire and begin receiving unreduced benefits as soon as they are eligible. Estimated Future Pension Benefit Payments (Dollar amounts in thousands) Total Year ending December 31, 2017 $ 16,009 2018 5,308 2019 5,059 2020 4,747 2021 4,646 2022-2026 18,583

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of Common Stock Available Under Share-Based Plans	Shares of Common Stock Available Under Share-Based Plans As of December 31, 2016 Shares Authorized Shares Available For Grant Omnibus Plan 8,631,641 1,998,949 Directors Plan 481,250 101,727
Nonqualified Stock Option Transactions	Nonqualified Stock Option Transactions (Amounts in thousands, except per share data) Year Ended December 31, 2016 Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (1) Aggregate Intrinsic Value (2) Options outstanding beginning balance 756 $ 32.55 Expired (270 ) 33.95 Options outstanding ending balance 486 $ 31.77 0.94 $ 558 Exercisable at the end of the year 486 $ 31.77 0.94 $ 558 (1) Represents the average remaining contractual life in years. (2) Aggregate intrinsic value represents the total pre-tax intrinsic value that would have been received by the option holders if they had exercised their options on December 31, 2016 . Intrinsic value equals the difference between the Company's average of the high and low stock price on the last trading day of the year and the option exercise price, multiplied by the number of shares. This amount will fluctuate with changes in the fair value of the Company's common stock.
Restricted Stock, Restricted Stock Unit, and Performance Share Award Transactions	Restricted Stock, Restricted Stock Unit, and Performance Share Award Transactions (Amounts in thousands, except per share data) Year Ended December 31, 2016 Restricted Stock/Unit Awards Performance Shares Number of Shares/Units Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Non-vested awards beginning balance 908 $ 15.92 338 $ 15.19 Granted 494 17.28 126 17.28 Vested (351 ) 14.69 (31 ) 14.69 Forfeited (62 ) 16.72 (25 ) 16.72 Non-vested awards ending balance 989 $ 16.95 408 $ 15.78
Effect of Recording Share-Based Compensation Expense	Effect of Recording Share-Based Compensation Expense (Dollar amounts in thousands) Years ended December 31, 2016 2015 2014 Total share-based compensation expense (1) $ 7,879 $ 7,242 $ 5,926 Income tax benefit 3,152 2,962 2,424 Share-based compensation expense, net of tax $ 4,727 $ 4,280 $ 3,502 Unrecognized compensation expense $ 9,990 $ 8,644 $ 6,937 Weighted-average amortization period remaining (in years) 1.3 1.4 1.3 (1) Comprised of restricted stock, restricted stock unit, and performance share awards expense.
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of Other Share-based Compensation, Activity	Other Restricted Stock, Restricted Stock Unit, and Performance Share Award Information (Amounts in thousands, except per share data) Years Ended December 31, 2016 2015 2014 Weighted-average grant date fair value of restricted stock, restricted stock unit, and performance share awards granted during the year $ 17.28 $ 16.95 $ 16.13 Total fair value of restricted stock and restricted stock unit awards vested during the year 12,231 7,615 7,546 Income tax benefit realized from the vesting/release of restricted stock and restricted stock unit awards 2,529 2,368 2,939

Regulatory and Capital Matters

Regulatory and Capital Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Banking and Thrift [Abstract]
Summary of Regulatory Capital Ratios	The following table outlines the Company's and the Bank's measures of capital as of the dates presented and the capital guidelines established by the Federal Reserve for the Company and the Bank to be categorized as adequately capitalized and the Bank to be categorized as "well-capitalized." Summary of Regulatory Capital Ratios (Dollar amounts in thousands) Actual Adequately Capitalized To Be Well-Capitalized Under Prompt Corrective Action Provisions Capital Ratio % Capital Ratio % Capital Ratio % As of December 31, 2016 Total capital to risk-weighted assets: First Midwest Bancorp, Inc. $ 1,225,529 12.23 $ 864,176 8.625 N/A N/A First Midwest Bank 1,043,482 10.73 838,741 8.625 $ 972,454 10.00 Tier 1 capital to risk-weighted assets: First Midwest Bancorp, Inc. 991,873 9.90 663,788 6.625 N/A N/A First Midwest Bank 956,399 9.83 644,251 6.625 777,963 8.00 Common equity Tier 1 to risk-weighted assets: First Midwest Bancorp, Inc. 941,315 9.39 513,496 5.125 N/A N/A First Midwest Bank 956,399 9.83 498,383 5.125 632,095 6.50 Tier 1 capital to average assets: First Midwest Bancorp, Inc. 991,873 8.99 441,473 4.000 N/A N/A First Midwest Bank 956,399 8.76 436,560 4.000 545,700 5.00 As of December 31, 2015 Total capital to risk-weighted assets: First Midwest Bancorp, Inc. $ 968,331 11.15 $ 695,029 8.000 N/A N/A First Midwest Bank 929,167 11.02 674,380 8.000 $ 842,974 10.00 Tier 1 capital to risk-weighted assets: First Midwest Bancorp, Inc. 893,476 10.28 521,272 6.000 N/A N/A First Midwest Bank 854,322 10.13 505,785 6.000 674,380 8.00 Common equity Tier 1 to risk-weighted assets: First Midwest Bancorp, Inc. 845,640 9.73 390,954 4.500 N/A N/A First Midwest Bank 854,322 10.13 379,338 4.500 547,933 6.50 Tier 1 capital to average assets: First Midwest Bancorp, Inc. 893,476 9.40 380,043 4.000 N/A N/A First Midwest Bank 854,322 9.09 375,950 4.000 469,937 5.00 N/A – Not applicable.

Derivative Instruments and He51

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Interest Rate Derivatives	Cash Flow Hedges (Dollar amounts in thousands) As of December 31, 2016 2015 Gross notional amount outstanding $ 1,470,000 $ 1,220,000 Derivative asset fair value 5,402 4,787 Derivative liability fair value (7,390 ) (8,950 ) Weighted-average interest rate received 1.37 % 1.24 % Weighted-average interest rate paid 1.11 % 0.75 % Weighted-average maturity (in years) 2.83 3.91 Fair Value Hedges (Dollar amounts in thousands) As of December 31, 2016 2015 Gross notional amount outstanding $ 5,958 $ 11,620 Derivative liability fair value (282 ) (643 ) Weighted-average interest rate received 2.63 % 2.25 % Weighted-average interest rate paid 5.96 % 6.36 % Weighted-average maturity (in years) 1.84 1.97 Fair value of derivative (1) $ 296 $ 665 (1) This amount represents the fair value if credit risk related contingent features were triggered.
Schedule of Derivative Instruments	Other Derivative Instruments (Dollar amounts in thousands) As of December 31, 2016 2015 Gross notional amount outstanding $ 1,656,612 $ 853,385 Derivative asset fair value 13,478 11,446 Derivative liability fair value (13,478 ) (11,446 ) Fair value of derivative (1) 13,753 11,939 (1) This amount represents the fair value if credit risk related contingent factors were triggered.
Offsetting Assets	The following table presents the fair value of the Company's derivatives and offsetting positions as of December 31, 2016 and 2015 . Fair Value of Offsetting Derivatives (Dollar amounts in thousands) As of December 31, 2016 2015 Assets Liabilities Assets Liabilities Gross amounts recognized $ 18,880 $ 21,150 $ 16,233 $ 21,039 Less: amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition (1) 18,880 21,150 16,233 21,039 Gross amounts not offset in the Consolidated Statements of Financial Condition: Offsetting derivative positions (10,889 ) (10,889 ) (4,791 ) (4,791 ) Cash collateral pledged — (10,261 ) — (16,248 ) Net credit exposure $ 7,991 $ — $ 11,442 $ — (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 December 31, 2016 and 2015 . Fair Value of Offsetting Derivatives (Dollar amounts in thousands) As of December 31, 2016 2015 Assets Liabilities Assets Liabilities Gross amounts recognized $ 18,880 $ 21,150 $ 16,233 $ 21,039 Less: amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition (1) 18,880 21,150 16,233 21,039 Gross amounts not offset in the Consolidated Statements of Financial Condition: Offsetting derivative positions (10,889 ) (10,889 ) (4,791 ) (4,791 ) Cash collateral pledged — (10,261 ) — (16,248 ) Net credit exposure $ 7,991 $ — $ 11,442 $ — (1) Included in other assets or other liabilities in the Consolidated Statements of Financial Condition.

Commitments, Guarantees, and 52

Commitments, Guarantees, and Contingent Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments Disclosure	Contractual or Notional Amounts of Financial Instruments (Dollar amounts in thousands) As of December 31, 2016 2015 Commitments to extend credit: Commercial, industrial, and agricultural $ 1,522,152 $ 1,303,056 Commercial real estate 397,423 366,250 Home equity 426,384 352,114 Other commitments (1) 214,943 203,121 Total commitments to extend credit $ 2,560,902 $ 2,224,541 Letters of credit $ 100,430 $ 100,610 Recourse on assets sold: Unpaid principal balance of loans sold $ 187,158 $ 196,389 Carrying value of recourse obligation (2) 142 87 (1) Other commitments includes installment and overdraft protection program commitments. (2) Included in other liabilities in the Consolidated Statements of Financial Condition.

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 As of December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets: Trading securities: Money market funds $ 1,645 $ — $ — $ 2,530 $ — $ — Mutual funds 16,275 — — 14,364 — — Total trading securities 17,920 — — 16,894 — — Securities available-for-sale: U.S. treasury securities 48,541 — — 16,980 — — U.S. agency securities — 183,637 — — 86,643 — CMOs — 1,047,446 — — 687,185 — MBSs — 332,655 — — 153,530 — Municipal securities — 270,846 — — 327,570 CDOs — — 33,260 — — 31,529 Equity securities — 3,065 — — 3,199 — Total securities available-for- sale 48,541 1,837,649 33,260 16,980 1,258,127 31,529 Mortgage servicing rights ("MSRs") (1) — — 6,120 — — 1,853 Derivative assets (1) — 18,880 — — 16,233 — Liabilities: Derivative liabilities (2) $ — $ 21,150 $ — $ — $ 21,039 $ — (1) Included in other assets in the Consolidated Statements of Financial Condition. (2) Included in other liabilities in the Consolidated Statements of Financial Condition.
Significant Unobservable Inputs Used in the Valuation of CDOs	The following table presents the ranges of significant, unobservable inputs used by the Company to determine the fair value of MSRs as December 31, 2016 and 2015 . Significant Unobservable Inputs Used in the Valuation of MSRs As of December 31, 2016 2015 Prepayment speed 7.7 % - 22.8% 10.1 % - 20.9% Maturity (months) 12 - 103 6 - 86 Discount rate 9.5 % - 13.0% 9.5 % - 13.0% The following table presents the ranges of significant, unobservable inputs calculated using the weighted average of the Issuers used by the Company as of December 31, 2016 and 2015 . Significant Unobservable Inputs Used in the Valuation of CDOs As of December 31, 2016 2015 Probability of prepayment 0.0 % - 10.9% 1.8 % - 15.1% Probability of default 16.7 % - 46.8% 19.1 % - 32.6% Loss given default 93.3 % - 98.9% 93.8 % - 97.1% Probability of deferral cure 7.6 % - 100.0% 15.2 % - 63.1%
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	A rollforward of the carrying value of CDOs for the three years ended December 31, 2016 is presented in the following table. Carrying Value of CDOs (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 31,529 $ 33,774 $ 18,309 Additions — — 6,549 Change in other comprehensive (loss) income (1) 2,337 (2,030 ) 13,495 Paydowns and sales (2) (606 ) (215 ) (4,579 ) Ending balance $ 33,260 $ 31,529 $ 33,774 (1) Included in unrealized holding (losses) gains in the Consolidated Statements of Comprehensive Income. (2) During the year ended December 31, 2014, one CDO with a carrying value of $1.3 million and four CDOs totaling $2.9 million , which were acquired in the Great Lakes transaction, were sold.
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 MSRs as December 31, 2016 and 2015 . Significant Unobservable Inputs Used in the Valuation of MSRs As of December 31, 2016 2015 Prepayment speed 7.7 % - 22.8% 10.1 % - 20.9% Maturity (months) 12 - 103 6 - 86 Discount rate 9.5 % - 13.0% 9.5 % - 13.0% The following table presents the ranges of significant, unobservable inputs calculated using the weighted average of the Issuers used by the Company as of December 31, 2016 and 2015 . Significant Unobservable Inputs Used in the Valuation of CDOs As of December 31, 2016 2015 Probability of prepayment 0.0 % - 10.9% 1.8 % - 15.1% Probability of default 16.7 % - 46.8% 19.1 % - 32.6% Loss given default 93.3 % - 98.9% 93.8 % - 97.1% Probability of deferral cure 7.6 % - 100.0% 15.2 % - 63.1%
Fair Value Inputs Mortgage Servicing Assets Quantitative Information	A rollforward of the carrying value of MSRs for the three years ended December 31, 2016 is presented in the following table. Carrying Value of MSRs (Dollar amounts in thousands) Years Ended December 31, 2016 2015 2014 Beginning balance $ 1,853 $ 1,728 $ 1,893 Additions from acquisition 3,092 — — New MSRs 1,263 342 315 Total (losses) gains included in earnings (1) : Changes in valuation inputs and assumptions 610 (11 ) (480 ) Other changes in fair value (2) (698 ) (206 ) — Ending balance $ 6,120 $ 1,853 $ 1,728 Contractual servicing fees earned during the year (1) $ 1,312 $ 546 $ 520 Total amount of loans being serviced for the benefit of others at the end of the year 640,530 242,915 220,372 (1) Included in mortgage banking income in the Consolidated Statements of Income and relate to assets still held at the end of the year. (2) Primarily represents changes in expected future cash flows over time due to payoffs and paydowns.
Fair Value Assets Measured On Annual Basis	The fair value of Pension Plan assets is presented in the following table by level in the fair value hierarchy. Annual Fair Value Measurements for Pension Plan Assets (Dollar amounts in thousands) As of December 31, 2016 As of December 31, 2015 Level 1 Level 2 Total Level 1 Level 2 Total Pension plan assets: Mutual funds (1) $ 29,071 $ — $ 29,071 $ 23,061 $ — $ 23,061 U.S. government and government agency securities 5,957 7,947 13,904 6,866 5,538 12,404 Corporate bonds — 7,010 7,010 — 9,569 9,569 Common stocks 7,526 — 7,526 11,330 — 11,330 Common trust funds — 7,678 7,678 — 8,539 8,539 Total pension plan assets $ 42,554 $ 22,635 $ 65,189 $ 41,257 $ 23,646 $ 64,903 (1) Includes mutual funds, money market funds, cash, cash equivalents, and accrued interest.
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 December 31, 2016 As of December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Collateral-dependent impaired loans (1) $ — $ — $ 22,019 $ — $ — $ 10,519 OREO (2) — — 8,624 — — 8,581 Loans held-for-sale (3) — — 10,484 — — 14,444 Assets held-for-sale (4) — — 4,075 — — 7,428 (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 December 31, 2016 As of December 31, 2015 Fair Value Hierarchy Carrying Fair Value Carrying Fair Value Assets: Cash and due from banks 1 $ 155,055 $ 155,055 $ 114,587 $ 114,587 Interest-bearing deposits in other banks 2 107,093 107,093 266,615 266,615 Securities held-to-maturity 2 22,291 18,212 23,152 20,054 FHLB and FRB stock 2 59,131 59,131 39,306 39,306 Loans 3 8,172,584 7,973,845 7,091,988 6,959,024 Investment in BOLI 3 219,746 219,746 209,601 209,601 Accrued interest receivable 3 34,384 34,384 27,847 27,847 Other interest-earning assets 3 834 834 1,982 1,982 Liabilities: Deposits 2 $ 8,828,603 $ 8,820,572 $ 8,097,738 $ 8,093,640 Borrowed funds 2 879,008 879,008 165,096 165,096 Senior and subordinated debt 2 194,603 197,888 201,208 205,726 Accrued interest payable 2 3,416 3,416 2,175 2,175

Condensed Parent Company Fina54

Condensed Parent Company Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Statements of Financial Condition - Parent Company Only	The following represents the condensed financial statements of First Midwest Bancorp, Inc., the Parent Company. Statements of Financial Condition (Parent Company only) (Dollar amounts in thousands) As of December 31, 2016 2015 Assets Cash and due from banks $ 140,217 $ 119,693 Investments in and advances to subsidiaries 1,279,065 1,194,173 Other assets 139,060 63,337 Total assets $ 1,558,342 $ 1,377,203 Liabilities and Stockholders' Equity Senior and subordinated debt $ 194,603 $ 201,208 Accrued interest payable and other liabilities 106,659 29,727 Stockholders' equity 1,257,080 1,146,268 Total liabilities and stockholders' equity $ 1,558,342 $ 1,377,203
Statements of Income - Parent Company Only	Statements of Income (Parent Company only) (Dollar amounts in thousands) Years ended December 31, 2016 2015 2014 Income Dividends from subsidiaries $ 86,791 $ 127,000 $ 56,881 Interest income 2,188 2,164 1,502 Securities transactions and other 215 584 6,451 Total income 89,194 129,748 64,834 Expenses Interest expense 12,477 12,545 12,062 Salaries and employee benefits 16,104 14,624 12,589 Other expenses 7,110 6,003 5,867 Total expenses 35,691 33,172 30,518 Income before income tax benefit and equity in undistributed (loss) income of subsidiaries 53,503 96,576 34,316 Income tax benefit 12,878 11,950 8,710 Income before equity in undistributed (loss) income of subsidiaries 66,381 108,526 43,026 Equity in undistributed income (loss) of subsidiaries 25,968 (26,462 ) 26,280 Net income 92,349 82,064 69,306 Net income applicable to non-vested restricted shares (1,043 ) (882 ) (836 ) Net income applicable to common shares $ 91,306 $ 81,182 $ 68,470
Statements of Cash Flows - Parent Company Only	Statements of Cash Flows (Parent Company only) (Dollar amounts in thousands) Years ended December 31, 2016 2015 2014 Operating Activities Net income $ 92,349 $ 82,064 $ 69,306 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed (income) loss of subsidiaries (25,968 ) 26,462 (26,280 ) Depreciation of premises, furniture, and equipment 2 7 6 Net gains on sales of securities — (1 ) (5,702 ) Share-based compensation expense 7,879 7,242 5,926 Tax expense related to share-based compensation (685 ) (1,200 ) (106 ) Net (increase) decrease in other assets (75,104 ) 23,699 4,599 Net increase (decrease) in other liabilities 74,571 (17,132 ) 14,063 Net cash provided by operating activities 73,044 121,141 61,812 Investing Activities Purchases of securities available-for-sale (14 ) — — Proceeds from sales and maturities of securities available-for-sale 601 310 8,540 Purchase of premises, furniture, and equipment — (5 ) — Net cash paid for acquisitions (14,905 ) (16,047 ) (15,809 ) Net cash used in investing activities (14,318 ) (15,742 ) (7,269 ) Financing Activities Net proceeds from the issuance of subordinated debt 146,484 — — Payments for the retirement of senior and subordinated debt (153,500 ) — — Treasury stock activity — (120 ) 369 Cash dividends paid (29,198 ) (27,036 ) (22,568 ) Restricted stock activity (2,476 ) (2,890 ) (2,781 ) Excess tax benefit related to share-based compensation 488 794 912 Net cash used in financing activities (38,202 ) (29,252 ) (24,068 ) Net increase in cash and cash equivalents 20,524 76,147 30,475 Cash and cash equivalents at beginning of year 119,693 43,546 13,071 Cash and cash equivalents at end of year $ 140,217 $ 119,693 $ 43,546 Supplemental Disclosures of Cash Flow Information: Common stock issued for acquisitions, net of issuance costs $ 54,896 $ — $ 38,300

Subsequent Events (Tables)

Subsequent Events (Tables)	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Acquisition activity	The following table presents the assets acquired and liabilities assumed, net of the fair value adjustments, in the NI Bancshares and Peoples transactions as of the acquisition date, including measurement period adjustments. The assets acquired and liabilities assumed, both intangible and tangible, were recorded at their estimated fair values as of the acquisition date and have been accounted for under the acquisition method of accounting. Acquisition Activity (Dollar amounts in thousands, except share and per share data) NI Bancshares Peoples March 8, 2016 December 3, 2015 Assets Cash and due from banks and interest-bearing deposits in other banks $ 72,533 $ 781 Securities available-for-sale 125,843 41,492 Securities held-to-maturity 1,864 — FHLB and FRB stock 1,549 558 Loans 396,886 53,766 OREO 2,863 515 Investment in BOLI 8,384 — Goodwill 21,751 7,665 Other intangible assets 10,409 580 Premises, furniture, and equipment 19,636 2,215 Accrued interest receivable and other assets 16,558 2,941 Total assets $ 678,276 $ 110,513 Liabilities Noninterest-bearing deposits $ 130,909 $ 15,869 Interest-bearing deposits 464,012 75,944 Total deposits 594,921 91,813 Borrowed funds 2,416 1,200 Intangible liabilities 230 — Accrued interest payable and other liabilities 10,627 672 Total liabilities 608,194 93,685 Consideration Paid Common stock (2016 - 3,042,494 shares issued at $18.059 per share), net of $48,000 in issuance costs 54,896 — Cash paid 15,186 16,828 Total consideration paid 70,082 16,828 $ 678,276 $ 110,513 The following table presents the assets acquired and liabilities assumed, net of preliminary fair value adjustments, in the Standard transaction as of the acquisition date. The assets acquired and liabilities assumed, both tangible and intangible, are presented at their estimated fair values as of the acquisition date and have been accounted for under the acquisition method of accounting. These fair value adjustments, including goodwill, are preliminary based on estimates and are subject to change as more information becomes available and after final analyses of the fair values of both tangible and intangible assets acquired and liabilities assumed are completed. Goodwill recorded in the acquisition, which reflects the increased Company presence in southern metropolitan Chicago and northwest Indiana and related synergies expected from the combined operations, is not tax deductible. Acquisition Activity (Dollar amounts in thousands, except share and per share data) Standard January 6, 2017 Assets Cash and due from banks and interest-bearing deposits in other banks $ 101,944 Securities available-for-sale 214,098 FHLB and FRB stock 3,247 Loans 1,795,562 OREO 9,223 Investment in BOLI 55,629 Goodwill 328,296 Other intangible assets 25,868 Premises, furniture, and equipment 56,253 Accrued interest receivable and other assets 48,707 Total assets $ 2,638,827 Liabilities Noninterest-bearing deposits $ 676,295 Interest-bearing deposits 1,347,760 Total deposits 2,024,055 Accrued interest payable and other liabilities 34,289 Total liabilities 2,058,344 Consideration Paid Common stock (21,057,085 shares issued at $25.34 per share), net of issuance costs 533,358 Cash paid 47,125 Total consideration paid 580,483 $ 2,638,827
Unaudited Pro Forma Combined Results of Operations	The unaudited pro forma combined results of operations for the for the year ended December 31, 2016 is presented as if the Standard acquisition had occurred on January 1, 2016, the first day of the Company's 2016 fiscal year. The unaudited pro forma combined results of operations is presented for illustrative purposes only and does not necessarily indicate the financial results of the combined companies had the companies actually been combined at the beginning of the period presented. Fair value adjustments included in the following table are preliminary and may be revised. The unaudited pro forma results of operations also does not consider any potential impacts of potential revenue enhancements, anticipated cost savings and expense efficiencies, or asset dispositions, among other factors. Acquisition and integration related expenses directly attributable to the Standard acquisition have been excluded from the following table and are estimated to total $27.0 million , of which $8.0 million was expensed during the year ended December 31, 2016. Unaudited Pro Forma Combined Results of Operations (Dollar amounts in thousands, except per share data) For the Year Ended December 31, 2016 Total revenues (1) $ 616,922 Net income 108,770 (1) Includes net interest income and total noninterest income.

Summary of Significant Accoun56

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2016segmentsubsidiary
Accounting Policies [Abstract]
Number of wholly-owned subsidiaries | subsidiary	3
Number of reportable segments | segment	1
Property, Plant and Equipment [Line Items]
Finite-lived intangible assets amortization period	13 years
Furniture And Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Furniture And Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Premises | Minimum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Premises | Maximum
Property, Plant and Equipment [Line Items]
Useful life	40 years

Recent Accounting Pronounceme57

Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	Dec. 31, 2016	Sep. 27, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Deferred gain, net	$ 81	$ 82.5

Acquisitions (Details) - Narrat

Acquisitions (Details) - Narrative $ in Thousands	Jan. 06, 2017USD ($)location	Mar. 08, 2016USD ($)location	Dec. 03, 2015USD ($)location	Dec. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Business Acquisition [Line Items]
Goodwill				$ 340,879	$ 340,879	$ 319,007	$ 310,589	$ 264,062
Acquisition and integration related expenses					14,352	$ 1,389	$ 13,872
Standard Bancshares, Inc.
Business Acquisition [Line Items]
Acquisition and integration related expenses					8,000
Standard Bancshares, Inc. | Subsequent Event
Business Acquisition [Line Items]
Number of retail branches acquired | location	35
Total assets	$ 2,638,827
Total deposits	2,024,055
Loans	1,795,562
Consideration transferred	580,483
Goodwill	$ 328,296
NI Bancshares Corporation
Business Acquisition [Line Items]
Number of retail branches acquired | location		10
Total assets		$ 678,276
Total deposits		594,921
Loans		396,886
Minimum value of trust assets under management acquired		700,000
Consideration transferred		70,082
Goodwill		$ 21,751
Adjustment to goodwill				$ 1,000
Peoples Bancorp, Inc.
Business Acquisition [Line Items]
Number of retail branches acquired | location			2
Total assets			$ 110,513
Total deposits			91,813
Loans			53,766
Consideration transferred			16,828
Goodwill			$ 7,665
Adjustment to goodwill					$ 121

Acquisitions (Details) - Acquis

Acquisitions (Details) - Acquisition Activity - USD ($) $ / shares in Units, $ in Thousands	Mar. 08, 2016	Dec. 03, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Goodwill			$ 340,879	$ 319,007	$ 310,589	$ 264,062
Liabilities
Intangible liabilities			$ 8,093
NI Bancshares Corporation
Assets
Cash and due from banks and interest-bearing deposits in other banks	$ 72,533
Securities available-for-sale	125,843
Securities held-to-maturity	1,864
FHLB and FRB stock	1,549
Loans	396,886
OREO	2,863
Investment in BOLI	8,384
Goodwill	21,751
Other intangible assets	10,409
Premises, furniture, and equipment	19,636
Accrued interest receivable and other assets	16,558
Total assets	678,276
Liabilities
Noninterest-bearing deposits	130,909
Interest-bearing deposits	464,012
Total deposits	594,921
Borrowed funds	2,416
Intangible liabilities	230
Accrued interest payable and other liabilities	10,627
Total liabilities	$ 608,194
Consideration Paid
Common stock, shares issued (in shares)	3,042,494
Shares issued (in dollars per share)	$ 18.059
Issuance costs	$ 48
Common stock (2016 - 3,042,494 shares issued at $18.059 per share), net of $48,000 in issuance costs	54,896
Cash paid	15,186
Total consideration paid	$ 70,082
Peoples Bancorp, Inc.
Assets
Cash and due from banks and interest-bearing deposits in other banks		$ 781
Securities available-for-sale		41,492
Securities held-to-maturity		0
FHLB and FRB stock		558
Loans		53,766
OREO		515
Investment in BOLI		0
Goodwill		7,665
Other intangible assets		580
Premises, furniture, and equipment		2,215
Accrued interest receivable and other assets		2,941
Total assets		110,513
Liabilities
Noninterest-bearing deposits		15,869
Interest-bearing deposits		75,944
Total deposits		91,813
Borrowed funds		1,200
Intangible liabilities		0
Accrued interest payable and other liabilities		672
Total liabilities		93,685
Consideration Paid
Common stock (2016 - 3,042,494 shares issued at $18.059 per share), net of $48,000 in issuance costs		0
Total consideration paid		$ 16,828

Securities (Details) - Securiti

Securities (Details) - Securities Portfolio - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	$ 22,291	$ 23,152
Fair Value	18,212	20,054
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	17,920	16,894
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	1,957,584	1,324,146
Gross Unrealized Gains	4,562	9,921
Gross Unrealized Losses	(42,696)	(27,431)
Fair Value	1,919,450	1,306,636
U.S. treasury securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	48,581	17,000
Gross Unrealized Gains	26	15
Gross Unrealized Losses	(66)	(35)
Fair Value	48,541	16,980
U.S. agency securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	183,528	86,461
Gross Unrealized Gains	519	351
Gross Unrealized Losses	(410)	(169)
Fair Value	183,637	86,643
Collateralized mortgage obligations (CMOs)
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	1,064,130	695,198
Gross Unrealized Gains	969	1,072
Gross Unrealized Losses	(17,653)	(9,085)
Fair Value	1,047,446	687,185
Other mortgage-backed securities (MBSs)
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	337,139	152,481
Gross Unrealized Gains	1,395	1,920
Gross Unrealized Losses	(5,879)	(871)
Fair Value	332,655	153,530
Municipal securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	273,319	321,437
Gross Unrealized Gains	1,245	6,443
Gross Unrealized Losses	(3,718)	(310)
Fair Value	270,846	327,570
Trust-preferred collateralized debt obligations (CDOs)
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	47,681	48,287
Gross Unrealized Gains	261	34
Gross Unrealized Losses	(14,682)	(16,792)
Fair Value	33,260	31,529
Equity securities
Schedule of Available-for-Sale Securities [Line Items]
Amortized Cost	3,206	3,282
Gross Unrealized Gains	147	86
Gross Unrealized Losses	(288)	(169)
Fair Value	3,065	3,199
Trading securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading Securities	17,920	16,894
Municipal securities
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	22,291	23,152
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4,079)	(3,098)
Fair Value	$ 18,212	$ 20,054

Securities (Details) - Remainin

Securities (Details) - Remaining Contractual Maturity of Securities - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-Sale Securities, Amortized Cost Basis [Abstract]
One year or less	$ 73,669
After one year to five years	429,166
After five years to ten years	2,592
After ten years	47,682
Securities that do not have a single contractual maturity date	1,404,475
Amortized Cost	1,957,584	$ 1,324,146
Available-for-Sale Securities, Fair Value [Abstract]
One year or less	71,428
After one year to five years	416,112
After five years to ten years	2,513
After ten years	46,231
Securities that do not have a single contractual maturity date	1,383,166
Total	1,919,450	1,306,636
Held-to-Maturity Securities, Amortized Cost [Abstract]
One year or less	2,336
After one year to five years	6,834
After five years to ten years	2,975
After ten years	10,146
Securities that do not have a single contractual maturity date	0
Total	22,291	23,152
Held-to-Maturity Securities, Fair Value [Abstract]
One year or less	1,909
After one year to five years	5,583
After five years to ten years	2,431
After ten years	8,289
Securities that do not have a single contractual maturity date	0
Total	$ 18,212	$ 20,054

Securities (Details) - Narrativ

Securities (Details) - Narrative - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-Sale Securities [Line Items]
Available-for-sale securities pledged as collateral	$ 1,100,000,000	$ 856,900,000
Held-to-maturity securities pledged as collateral	0	0
Net realized gains on sales of securities	1,420,000	2,373,000	$ 8,125,000
Municipal securities
Schedule of Available-for-Sale Securities [Line Items]
Net realized gains on sales of securities	1,100,000
MBSs and CMOs
Schedule of Available-for-Sale Securities [Line Items]
Net realized gains on sales of securities	$ 304,000
Available-for-sale securities, excluding other mortgage-backed securities
Schedule of Available-for-Sale Securities [Line Items]
Net realized gains on sales of securities		521,000
CDOs
Schedule of Available-for-Sale Securities [Line Items]
Net realized gains on sales of securities		$ 1,900,000	3,500,000
Equity securities
Schedule of Available-for-Sale Securities [Line Items]
Net realized gains on sales of securities			$ 4,600,000

Securities (Details) - Securi63

Securities (Details) - Securities Gains - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gains on sales of securities:
Gross realized gains	$ 1,589	$ 2,519	$ 8,188
Gross realized losses	(169)	(146)	(63)
Net realized gains on sales of securities	1,420	2,373	8,125
Non-cash impairment charges:
OTTI	0	0	(28)
Net realized gains	$ 1,420	$ 2,373	$ 8,097

Securities (Details) - Changes

Securities (Details) - Changes In Credit Losses Recognized In Earnings $ in Thousands		12 Months Ended
		Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)security	Dec. 31, 2014USD ($)security
Changes in Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance		$ 23,345	$ 23,516	$ 32,422
OTTI included in earnings:
Losses on securities that previously had OTTI	[1]	0	0	28
Losses on securities that did not previously have OTTI	[1]	0	0	0
Ending balance		23,345	23,345	23,516
Reduction for securities sales	[2]	$ 0	$ 171	8,934
CMOs
OTTI included in earnings:
Number of CMOs sold | security			1
Reduction for securities sales			$ 1,300
CDOs
OTTI included in earnings:
Reduction for securities sales				$ 1,300
Number Of CDOs Sold | security				1
Municipal securities
OTTI included in earnings:
Reduction for securities sales				$ 357
Number Of Municipal securities sold | security				1
[1]	Included in net securities gains in the Consolidated Statements of Income.
[2]	These reductions were driven by the sale of one CMO with a carrying value of $1.3 million during the year ended December 31, 2015 and one CDO with a carrying value of $1.3 million and one municipal security with a carrying value of $357,000 during the year ended December 31, 2014

Securities (Details) - Securi65

Securities (Details) - Securities In An Unrealized Loss Position $ in Thousands	Dec. 31, 2016USD ($)security	Dec. 31, 2015USD ($)security
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	695	252
Fair Value - Less Than 12 Months	$ 974,337	$ 428,035
Unrealized Losses - Less Than 12 Months	18,720	4,897
Fair Value - 12 Months or Longer	567,538	337,516
Unrealized Losses - 12 Months or Longer	23,976	22,534
Fair Value - Total	1,541,875	765,551
Unrealized Losses - Total	$ 42,696	$ 27,431
U.S. treasury securities
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	16	4
Fair Value - Less Than 12 Months	$ 33,505	$ 7,946
Unrealized Losses - Less Than 12 Months	61	35
Fair Value - 12 Months or Longer	3,995	0
Unrealized Losses - 12 Months or Longer	5	0
Fair Value - Total	37,500	7,946
Unrealized Losses - Total	$ 66	$ 35
U.S. agency securities
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	28	10
Fair Value - Less Than 12 Months	$ 62,064	$ 30,620
Unrealized Losses - Less Than 12 Months	364	169
Fair Value - 12 Months or Longer	11,814	0
Unrealized Losses - 12 Months or Longer	46	0
Fair Value - Total	73,878	30,620
Unrealized Losses - Total	$ 410	$ 169
CMOs
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	194	133
Fair Value - Less Than 12 Months	$ 523,233	$ 309,787
Unrealized Losses - Less Than 12 Months	10,309	3,110
Fair Value - 12 Months or Longer	411,758	257,362
Unrealized Losses - 12 Months or Longer	7,344	5,975
Fair Value - Total	934,991	567,149
Unrealized Losses - Total	$ 17,653	$ 9,085
MBSs
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	68	27
Fair Value - Less Than 12 Months	$ 221,174	$ 63,028
Unrealized Losses - Less Than 12 Months	4,726	427
Fair Value - 12 Months or Longer	77,780	31,980
Unrealized Losses - 12 Months or Longer	1,154	444
Fair Value - Total	298,954	95,008
Unrealized Losses - Total	$ 5,880	$ 871
Municipal securities
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	380	68
Fair Value - Less Than 12 Months	$ 133,957	$ 8,135
Unrealized Losses - Less Than 12 Months	3,059	65
Fair Value - 12 Months or Longer	29,280	24,227
Unrealized Losses - 12 Months or Longer	659	245
Fair Value - Total	163,237	32,362
Unrealized Losses - Total	$ 3,718	$ 310
CDOs
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	7	8
Fair Value - Less Than 12 Months	$ 0	$ 8,034
Unrealized Losses - Less Than 12 Months	0	971
Fair Value - 12 Months or Longer	30,592	21,642
Unrealized Losses - 12 Months or Longer	14,682	15,821
Fair Value - Total	30,592	29,676
Unrealized Losses - Total	$ 14,682	$ 16,792
Equity securities
Securities in An Unrealized Loss Position [Line Items]
Number of Securities | security	2	2
Fair Value - Less Than 12 Months	$ 404	$ 485
Unrealized Losses - Less Than 12 Months	201	120
Fair Value - 12 Months or Longer	2,319	2,305
Unrealized Losses - 12 Months or Longer	86	49
Fair Value - Total	2,723	2,790
Unrealized Losses - Total	$ 287	$ 169
Municipal securities
Schedule of Held-to-Maturity Securities [Line Items]
Number of Securities | security	14	19
Fair Value - Less than 12 Months	$ 0	$ 20,054
Unrealized Losses - Less than 12 Months	0	3,098
Fair Value - 12 Months or Longer	18,212	0
Unrealized Losses - 12 Months or Longer	4,079	0
Fair Value - Total	18,212	20,054
Unrealized Losses - Total	$ 4,079	$ 3,098

Loans (Details) - Loan Portfoli

Loans (Details) - Loan Portfolio - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Covered loans	[1]	$ 23,274	$ 30,775
Total loans		8,254,145	7,161,715
Deferred loan fees included in total loans		3,838	5,191
Overdrawn demand deposits included in total loans		7,836	2,810
Commercial, industrial, and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		3,217,154	2,912,166
Commercial, industrial, and agricultural | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		2,827,658	2,524,726
Total loans		2,827,658	2,524,726
Commercial, industrial, and agricultural | Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		389,496	387,440
Total loans		389,496	387,440
Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		3,626,760	3,071,850
Total loans		3,626,760	3,071,850
Commercial real estate loans | Office, retail, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,581,827	1,395,454
Total loans		1,581,827	1,395,454
Commercial real estate loans | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		614,034	528,324
Total loans		614,034	528,324
Commercial real estate loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		451,540	216,882
Total loans		451,540	216,882
Commercial real estate loans | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		979,359	931,190
Total loans		979,359	931,190
Total corporate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		6,843,914	5,984,016
Total loans		6,843,914	5,984,016
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		1,386,957	1,146,924
Total loans		1,386,957	1,146,924
Consumer loans | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		732,604	653,468
Total loans		732,604	653,468
Consumer loans | 1-4 family mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		416,354	355,854
Total loans		416,354	355,854
Consumer loans | Installment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		237,999	137,602
Total loans		$ 237,999	$ 137,602
[1]	For information on covered loans, see Note 6, "Acquired and Covered Loans."

Loans (Details) - Carrying Valu

Loans (Details) - Carrying Value of Loans Pledged - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans pledged to secure:
FHLB advances	$ 3,667,202	$ 3,057,421
FRB's Discount Window Primary Credit Program	777,950	841,808
Total	$ 4,445,152	$ 3,899,229

Loans (Details) - Loans Sales

Loans (Details) - Loans Sales - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total net gains on loan sales		$ 8,931	$ 6,847	$ 4,069
Corporate loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales		54,681	31,091	23,222
Less book value of loans sold		52,821	29,535	22,924
Total net gains on loan sales	[1]	1,860	1,556	298
1-4 family mortgage loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales		290,383	185,308	148,680
Less book value of loans sold		283,312	180,017	144,909
Total net gains on loan sales	[2]	$ 7,071	$ 5,291	$ 3,771
[1]	Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Consolidated Statements of Income.
[2]	Net gains on mortgage loan sales are included in mortgage banking income in the Consolidated Statements of Income.

Acquired and Covered Loans (Det

Acquired and Covered Loans (Details) - Narrative $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)transaction	Dec. 31, 2014USD ($)
Acquired Loans [Abstract]
Number Of FDIC Assisted Transactions With Expired Loss Share Agreements Relating To Non-residential Mortgage Loans | transaction		3
Non-residential Mortgage Loans With Expired Loss Share Agreements	$ 14.9	$ 21
Renewed non-purchased credit impaired loans	117.6	61.6
Acquired and Covered Receivables
Certain Loans Acquired in Transfer Accounted for as Debt Securities Accretable Yield Movement Schedule [Line Items]
Accretion on acquired loans	$ 14.6	$ 16.3	$ 13.6

Acquired and Covered Loans (D70

Acquired and Covered Loans (Details) - Acquired and Covered Loans - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Acquired Loans [Line Items]
Non-PCI	$ 628,718	$ 555,362
Total	690,385	615,567
Acquired loans
Acquired Loans [Line Items]
Non-PCI	613,339	534,506
Total	667,111	584,792
Covered Loans
Acquired Loans [Line Items]
Non-PCI	15,379	20,856
Total	23,274	30,775
Receivables acquired with deteriorated credit quality
Acquired Loans [Line Items]
PCI	61,667	60,205
Receivables acquired with deteriorated credit quality | Acquired loans
Acquired Loans [Line Items]
PCI	53,772	50,286
Receivables acquired with deteriorated credit quality | Covered Loans
Acquired Loans [Line Items]
PCI	$ 7,895	$ 9,919

Acquired and Covered Loans (D71

Acquired and Covered Loans (Details) - Changes in FDIC Indemnification Asset - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
FDIC Indemnification Asset [Roll Forward]
Beginning balance	$ 3,903	$ 8,452	$ 16,585
Amortization	(1,185)	(1,461)	(3,315)
Change in expected reimbursements from the FDIC for changes in expected credit losses	330	1,313	(481)
Net payments to (from) the FDIC	1,474	(4,401)	(4,337)
Ending balance	$ 4,522	$ 3,903	$ 8,452

Acquired and Covered Loans (D72

Acquired and Covered Loans (Details) - Changes in Accretable Yield - Receivables acquired with deteriorated credit quality - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in Accretable Yield [Roll Forward]
Beginning balance		$ 24,912	$ 28,244	$ 36,792
Additions		3,981	1,168	3,517
Accretion		(8,063)	(11,311)	(12,535)
Other	[1]	(1,444)	6,811	470
Ending balance		$ 19,386	$ 24,912	$ 28,244
[1]	Decreases result from the resolution of certain loans occurring earlier than anticipated while increases represent a rise in the expected future cash cash flows to be collected over the remaining estimated life of the underlying portfolio.

Past Due Loans, Allowance For73

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Aging Analysis of Past Due Loans and Non-Performing Loans by Class - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 8,204,440	$ 7,119,965
Past Due	49,705	41,750
Total loans	8,254,145	7,161,715
Non-accrual	59,289	29,430
90 Days or More Past Due, Still Accruing Interest	5,009	3,057
Covered loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	22,097	29,808
Past Due	1,177	967
Total loans	23,274	30,775
Non-accrual	479	555
90 Days or More Past Due, Still Accruing Interest	133	174
30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	22,923	19,049
30-89 Days Past Due | Covered loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	918	405
90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	26,782	22,701
90 Days or More Past Due | Covered loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	259	562
Commercial, industrial, and agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans	3,217,154	2,912,166
Commercial, industrial, and agricultural | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,816,442	2,516,197
Past Due	11,216	8,529
Total loans	2,827,658	2,524,726
Non-accrual	29,938	5,587
90 Days or More Past Due, Still Accruing Interest	374	857
Commercial, industrial, and agricultural | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	388,596	387,109
Past Due	900	331
Total loans	389,496	387,440
Non-accrual	181	355
90 Days or More Past Due, Still Accruing Interest	736	0
Commercial, industrial, and agricultural | 30-89 Days Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,426	4,956
Commercial, industrial, and agricultural | 30-89 Days Past Due | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	245
Commercial, industrial, and agricultural | 90 Days or More Past Due | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,790	3,573
Commercial, industrial, and agricultural | 90 Days or More Past Due | Agricultural
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	900	86
Commercial real estate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	3,601,628	3,051,916
Past Due	25,132	19,934
Total loans	3,626,760	3,071,850
Non-accrual	20,766	14,187
90 Days or More Past Due, Still Accruing Interest	3,259	1,213
Commercial real estate loans | Office, retail, and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,563,867	1,386,383
Past Due	17,960	9,071
Total loans	1,581,827	1,395,454
Non-accrual	17,277	6,875
90 Days or More Past Due, Still Accruing Interest	1,129	4
Commercial real estate loans | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	612,428	526,625
Past Due	1,606	1,699
Total loans	614,034	528,324
Non-accrual	311	796
90 Days or More Past Due, Still Accruing Interest	604	548
Commercial real estate loans | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	450,927	216,377
Past Due	613	505
Total loans	451,540	216,882
Non-accrual	286	905
90 Days or More Past Due, Still Accruing Interest	0	0
Commercial real estate loans | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	974,406	922,531
Past Due	4,953	8,659
Total loans	979,359	931,190
Non-accrual	2,892	5,611
90 Days or More Past Due, Still Accruing Interest	1,526	661
Commercial real estate loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,824	6,763
Commercial real estate loans | 30-89 Days Past Due | Office, retail, and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,327	2,647
Commercial real estate loans | 30-89 Days Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	858	541
Commercial real estate loans | 30-89 Days Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	332	0
Commercial real estate loans | 30-89 Days Past Due | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,307	3,575
Commercial real estate loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	17,308	13,171
Commercial real estate loans | 90 Days or More Past Due | Office, retail, and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	12,633	6,424
Commercial real estate loans | 90 Days or More Past Due | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	748	1,158
Commercial real estate loans | 90 Days or More Past Due | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	281	505
Commercial real estate loans | 90 Days or More Past Due | Other commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,646	5,084
Total corporate loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	6,806,666	5,955,222
Past Due	37,248	28,794
Total loans	6,843,914	5,984,016
Non-accrual	50,885	20,129
90 Days or More Past Due, Still Accruing Interest	4,369	2,070
Total corporate loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	14,250	11,964
Total corporate loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	22,998	16,830
Consumer loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,375,677	1,134,935
Past Due	11,280	11,989
Total loans	1,386,957	1,146,924
Non-accrual	7,925	8,746
90 Days or More Past Due, Still Accruing Interest	507	813
Consumer loans | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	726,676	647,175
Past Due	5,928	6,293
Total loans	732,604	653,468
Non-accrual	4,986	5,310
90 Days or More Past Due, Still Accruing Interest	17	216
Consumer loans | 1-4 family mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	412,737	350,980
Past Due	3,617	4,874
Total loans	416,354	355,854
Non-accrual	2,939	3,416
90 Days or More Past Due, Still Accruing Interest	231	528
Consumer loans | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	236,264	136,780
Past Due	1,735	822
Total loans	237,999	137,602
Non-accrual	0	20
90 Days or More Past Due, Still Accruing Interest	259	69
Consumer loans | 30-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,755	6,680
Consumer loans | 30-89 Days Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,627	3,247
Consumer loans | 30-89 Days Past Due | 1-4 family mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,652	2,680
Consumer loans | 30-89 Days Past Due | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,476	753
Consumer loans | 90 Days or More Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,525	5,309
Consumer loans | 90 Days or More Past Due | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,301	3,046
Consumer loans | 90 Days or More Past Due | 1-4 family mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	965	2,194
Consumer loans | 90 Days or More Past Due | Installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 259	$ 69

Past Due Loans, Allowance For74

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Allowance for Credit Losses - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	$ 74,855	$ 74,510	$ 87,121
Charge-offs	(23,293)	(26,917)	(40,184)
Recoveries	4,763	6,701	8,205
Net charge-offs	(18,530)	(20,216)	(31,979)
Provision for loan losses and other	30,758	20,561	19,368
Ending Balance	87,083	74,855	74,510
Covered Loans
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	1,638	7,226	12,559
Charge-offs	(140)	(634)	(1,012)
Recoveries	0	120	1,199
Net charge-offs	(140)	(514)	187
Provision for loan losses and other	(580)	(5,074)	(5,520)
Ending Balance	918	1,638	7,226
Reserve for Unfunded Commitments
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	1,225	1,816	1,616
Charge-offs	0	0	0
Recoveries	0	0	0
Net charge-offs	0	0	0
Provision for loan losses and other	(225)	(591)	200
Ending Balance	1,000	1,225	1,816
Commercial, Industrial, and Agricultural
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	37,074	29,458	30,381
Charge-offs	(9,844)	(15,885)	(17,424)
Recoveries	2,451	2,573	3,800
Net charge-offs	(7,393)	(13,312)	(13,624)
Provision for loan losses and other	11,028	20,928	12,701
Ending Balance	40,709	37,074	29,458
Commercial Real Estate Loans
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	23,106
Ending Balance	31,962	23,106
Commercial Real Estate Loans | Office, Retail, and Industrial
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	13,116	10,992	10,405
Charge-offs	(4,707)	(2,887)	(7,345)
Recoveries	337	467	497
Net charge-offs	(4,370)	(2,420)	(6,848)
Provision for loan losses and other	8,788	4,544	7,435
Ending Balance	17,534	13,116	10,992
Commercial Real Estate Loans | Multi-family
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	2,462	2,249	2,017
Charge-offs	(307)	(545)	(943)
Recoveries	97	15	87
Net charge-offs	(210)	(530)	(856)
Provision for loan losses and other	1,002	743	1,088
Ending Balance	3,254	2,462	2,249
Commercial Real Estate Loans | Construction
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	1,440	2,297	6,316
Charge-offs	(134)	(136)	(1,052)
Recoveries	56	350	166
Net charge-offs	(78)	214	(886)
Provision for loan losses and other	2,082	(1,071)	(3,133)
Ending Balance	3,444	1,440	2,297
Commercial Real Estate Loans | Other Commercial Real Estate
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	6,088	8,327	10,817
Charge-offs	(2,932)	(2,643)	(4,834)
Recoveries	524	1,993	1,727
Net charge-offs	(2,408)	(650)	(3,107)
Provision for loan losses and other	4,050	(1,589)	617
Ending Balance	7,730	6,088	8,327
Consumer Loans
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	11,812
Ending Balance	12,494	11,812
Consumer Loans | Consumer Loans
Allowance for Credit Losses by Portfolio Segment [Roll Forward]
Beginning balance	11,812	12,145	13,010
Charge-offs	(5,229)	(4,187)	(7,574)
Recoveries	1,298	1,183	729
Net charge-offs	(3,931)	(3,004)	(6,845)
Provision for loan losses and other	4,613	2,671	5,980
Ending Balance	$ 12,494	$ 11,812	$ 12,145

Past Due Loans, Allowance For75

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Loans and Related Allowance for Credit Losses by Portfolio Segment - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	$ 42,650	$ 13,676
Loans Collectively Evaluated for Impairment	8,149,828	7,087,834
Loans	8,254,145	7,161,715
Allowance for Credit Losses Individually Evaluated for Impairment	525	1,598
Allowance for Credit Losses Collectively Evaluated for Impairment	81,864	68,003
Total Allowance for Credit Losses	87,083	74,855	$ 74,510	$ 87,121
Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	61,667	60,205
Total Allowance for Credit Losses	4,694	5,254
Covered loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	0	0
Loans Collectively Evaluated for Impairment	15,379	20,856
Loans	23,274	30,775
Allowance for Credit Losses Individually Evaluated for Impairment	0	0
Allowance for Credit Losses Collectively Evaluated for Impairment	109	248
Total Allowance for Credit Losses	918	1,638	7,226	12,559
Covered loans | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	7,895	9,919
Total Allowance for Credit Losses	809	1,390
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	1,225
Total Allowance for Credit Losses	1,000	1,225	1,816	1,616
Reserve for unfunded commitments | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	0	0
Total Allowance for Credit Losses	0	0
Commercial, industrial, and agricultural
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	24,645	2,871
Loans Collectively Evaluated for Impairment	3,189,327	2,902,361
Loans	3,217,154	2,912,166
Allowance for Credit Losses Individually Evaluated for Impairment	507	883
Allowance for Credit Losses Collectively Evaluated for Impairment	39,554	35,378
Total Allowance for Credit Losses	40,709	37,074	29,458	30,381
Commercial, industrial, and agricultural | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	3,182	6,934
Total Allowance for Credit Losses	648	813
Commercial real estate loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	18,005	10,805
Loans Collectively Evaluated for Impairment	3,567,621	3,028,658
Loans	3,626,760	3,071,850
Allowance for Credit Losses Individually Evaluated for Impairment	18	715
Allowance for Credit Losses Collectively Evaluated for Impairment	29,100	19,727
Total Allowance for Credit Losses	31,962	23,106
Commercial real estate loans | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	41,134	32,387
Total Allowance for Credit Losses	2,844	2,664
Commercial real estate loans | Office, retail, and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	16,287	6,162
Loans Collectively Evaluated for Impairment	1,553,234	1,376,789
Loans	1,581,827	1,395,454
Allowance for Credit Losses Individually Evaluated for Impairment	0	715
Allowance for Credit Losses Collectively Evaluated for Impairment	16,148	10,833
Total Allowance for Credit Losses	17,534	13,116	10,992	10,405
Commercial real estate loans | Office, retail, and industrial | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	12,306	12,503
Total Allowance for Credit Losses	1,386	1,568
Commercial real estate loans | Multi-family
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	398	800
Loans Collectively Evaluated for Impairment	601,429	526,037
Loans	614,034	528,324
Allowance for Credit Losses Individually Evaluated for Impairment	0	0
Allowance for Credit Losses Collectively Evaluated for Impairment	3,059	2,367
Total Allowance for Credit Losses	3,254	2,462	2,249	2,017
Commercial real estate loans | Multi-family | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	12,207	1,487
Total Allowance for Credit Losses	195	95
Commercial real estate loans | Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	34	178
Loans Collectively Evaluated for Impairment	447,058	212,671
Loans	451,540	216,882
Allowance for Credit Losses Individually Evaluated for Impairment	0	0
Allowance for Credit Losses Collectively Evaluated for Impairment	3,280	1,160
Total Allowance for Credit Losses	3,444	1,440	2,297	6,316
Commercial real estate loans | Construction | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	4,448	4,033
Total Allowance for Credit Losses	164	280
Commercial real estate loans | Other commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	1,286	3,665
Loans Collectively Evaluated for Impairment	965,900	913,161
Loans	979,359	931,190
Allowance for Credit Losses Individually Evaluated for Impairment	18	0
Allowance for Credit Losses Collectively Evaluated for Impairment	6,613	5,367
Total Allowance for Credit Losses	7,730	6,088	$ 8,327	$ 10,817
Commercial real estate loans | Other commercial real estate | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	12,173	14,364
Total Allowance for Credit Losses	1,099	721
Total corporate loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	42,650	13,676
Loans Collectively Evaluated for Impairment	6,756,948	5,931,019
Loans	6,843,914	5,984,016
Allowance for Credit Losses Individually Evaluated for Impairment	525	1,598
Allowance for Credit Losses Collectively Evaluated for Impairment	68,654	55,105
Total Allowance for Credit Losses	72,671	60,180
Total corporate loans | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	44,316	39,321
Total Allowance for Credit Losses	3,492	3,477
Consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Individually Evaluated for Impairment	0	0
Loans Collectively Evaluated for Impairment	1,377,501	1,135,959
Loans	1,386,957	1,146,924
Allowance for Credit Losses Individually Evaluated for Impairment	0	0
Allowance for Credit Losses Collectively Evaluated for Impairment	12,101	11,425
Total Allowance for Credit Losses	12,494	11,812
Consumer loans | Receivables acquired with deteriorated credit quality
Financing Receivable, Allowance for Credit Losses [Line Items]
PCI	9,456	10,965
Total Allowance for Credit Losses	$ 393	$ 387

Past Due Loans, Allowance For76

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Impaired Loans Individually Evaluated by Class - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	$ 29,314	$ 10,970
Recorded Investment in Loans with a Specific Reserve	13,336	2,706
Unpaid Principal Balance	53,144	22,318
Specific Reserve	525	1,598
Commercial, industrial, and agricultural | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	11,579	1,673
Recorded Investment in Loans with a Specific Reserve	13,066	1,198
Unpaid Principal Balance	29,514	4,592
Specific Reserve	507	883
Commercial, industrial, and agricultural | Agricultural
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 loans
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	17,735	9,297
Recorded Investment in Loans with a Specific Reserve	270	1,508
Unpaid Principal Balance	23,630	17,726
Specific Reserve	18	715
Commercial real estate loans | Office, retail, and industrial
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	16,287	4,654
Recorded Investment in Loans with a Specific Reserve	0	1,508
Unpaid Principal Balance	21,057	12,083
Specific Reserve	0	715
Commercial real estate loans | Multi-family
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	398	800
Recorded Investment in Loans with a Specific Reserve	0	0
Unpaid Principal Balance	398	941
Specific Reserve	0	0
Commercial real estate loans | Construction
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	34	178
Recorded Investment in Loans with a Specific Reserve	0	0
Unpaid Principal Balance	34	299
Specific Reserve	0	0
Commercial real estate loans | Other commercial real estate
Financing Receivable, Impaired [Line Items]
Recorded Investment in Loans with No Specific Reserve	1,016	3,665
Recorded Investment in Loans with a Specific Reserve	270	0
Unpaid Principal Balance	2,141	4,403
Specific Reserve	$ 18	$ 0

Past Due Loans, Allowance For77

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Impaired Loans Individually Evaluated by Class (Continued) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		$ 25,396	$ 26,366	$ 48,163
Interest Income Recognized	[1]	492	390	759
Commercial, industrial, and agricultural | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		9,178	8,940	16,137
Interest Income Recognized	[1]	104	163	371
Commercial, industrial, and agricultural | Agricultural
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		0	0	0
Interest Income Recognized	[1]	0	0	0
Commercial real estate loans
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		16,218	17,426	32,026
Interest Income Recognized	[1]	388	227	388
Commercial real estate loans | Office, retail, and industrial
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		12,867	9,359	19,003
Interest Income Recognized	[1]	291	52	245
Commercial real estate loans | Multi-family
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		479	855	1,245
Interest Income Recognized	[1]	11	13	5
Commercial real estate loans | Construction
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		63	3,902	5,764
Interest Income Recognized	[1]	0	118	0
Commercial real estate loans | Other commercial real estate
Financing Receivable, Impaired [Line Items]
Average Recorded Investment		2,809	3,310	6,014
Interest Income Recognized	[1]	$ 86	$ 44	$ 138
[1]	Recorded using the cash basis of accounting.

Past Due Loans, Allowance For78

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Credit Quality Indicators by Class, Excluding Covered Loans - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Commercial, industrial, and agricultural | Commercial and industrial
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		$ 2,827,658	$ 2,524,726
Commercial, industrial, and agricultural | Commercial and industrial | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		2,638,833	2,379,992
Commercial, industrial, and agricultural | Commercial and industrial | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	92,340	86,263
Commercial, industrial, and agricultural | Commercial and industrial | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	66,547	52,884
Commercial, industrial, and agricultural | Commercial and industrial | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	29,938	5,587
Commercial, industrial, and agricultural | Agricultural
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		389,496	387,440
Commercial, industrial, and agricultural | Agricultural | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		366,382	381,523
Commercial, industrial, and agricultural | Agricultural | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	17,039	0
Commercial, industrial, and agricultural | Agricultural | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	5,894	5,562
Commercial, industrial, and agricultural | Agricultural | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	181	355
Commercial real estate loans
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		3,626,760	3,071,850
Commercial real estate loans | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		3,488,415	2,937,818
Commercial real estate loans | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	50,296	56,630
Commercial real estate loans | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	67,283	63,215
Commercial real estate loans | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	20,766	14,187
Commercial real estate loans | Office, retail, and industrial
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		1,581,827	1,395,454
Commercial real estate loans | Office, retail, and industrial | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		1,491,030	1,320,164
Commercial real estate loans | Office, retail, and industrial | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	34,007	32,627
Commercial real estate loans | Office, retail, and industrial | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	39,513	35,788
Commercial real estate loans | Office, retail, and industrial | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	17,277	6,875
Commercial real estate loans | Multi-family
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		614,034	528,324
Commercial real estate loans | Multi-family | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		607,324	517,412
Commercial real estate loans | Multi-family | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	4,370	6,146
Commercial real estate loans | Multi-family | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	2,029	3,970
Commercial real estate loans | Multi-family | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	311	796
Commercial real estate loans | Construction
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		451,540	216,882
Commercial real estate loans | Construction | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		438,946	201,496
Commercial real estate loans | Construction | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	111	4,678
Commercial real estate loans | Construction | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	12,197	9,803
Commercial real estate loans | Construction | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	286	905
Commercial real estate loans | Other commercial real estate
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		979,359	931,190
Commercial real estate loans | Other commercial real estate | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		951,115	898,746
Commercial real estate loans | Other commercial real estate | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	11,808	13,179
Commercial real estate loans | Other commercial real estate | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	13,544	13,654
Commercial real estate loans | Other commercial real estate | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	2,892	5,611
Total corporate loans
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		6,843,914	5,984,016
Total corporate loans | Pass
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class		6,493,630	5,699,333
Total corporate loans | Special Mention
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[1],[2]	159,675	142,893
Total corporate loans | Substandard
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[2],[3]	139,724	121,661
Total corporate loans | Non-accrual
Past Due Loans, Allowance For Credit Losses, and Impaired Loans (Details) - Credit Quality Indicators by Class, Excluding Covered Loans [Line Items
Credit Quality Indicators by Class	[4]	$ 50,885	$ 20,129
[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 $834,000 as of December 31, 2016 and $862,000 as of December 31, 2015.
[3]	Loans categorized as substandard exhibit a well-defined weakness 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 a well-defined weakness that may jeopardize the liquidation of the debt or result in a loss if the deficiencies are not corrected.

Past Due Loans, Allowance For79

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Credit Quality Indicators by Class, Excluding Covered Loans (Continued) - Consumer loans - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
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	$ 1,386,957	$ 1,146,924
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	1,379,032	1,138,178
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	7,925	8,746
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	732,604	653,468
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	727,618	648,158
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	4,986	5,310
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	416,354	355,854
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	413,415	352,438
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	2,939	3,416
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	237,999	137,602
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	237,999	137,582
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	$ 20

Past Due Loans, Allowance For80

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - Narrative - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Modifications [Line Items]
Accruing	$ 2,291,000	$ 2,743,000
Valuation allowance on TDR loans	0	758,000
Commitments to lend additional funds on TDR loans	0	0
Special mention and substandard loans
Financing Receivable, Modifications [Line Items]
Accruing	$ 834,000	$ 862,000

Past Due Loans, Allowance For81

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - TDRs By Class - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Modifications [Line Items]
Accruing		$ 2,291	$ 2,743
Non-accrual	[1]	6,297	2,324
Total		8,588	5,067	$ 23,608
Commercial, industrial, and agricultural | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Accruing		281	294
Non-accrual	[1]	150	1,050
Total		431	1,344
Commercial, industrial, and agricultural | Agricultural
Financing Receivable, Modifications [Line Items]
Accruing		0	0
Non-accrual	[1]	0	0
Total		0	0
Commercial real estate loans
Financing Receivable, Modifications [Line Items]
Accruing		1,009	1,102
Non-accrual	[1]	4,949	186
Total		5,958	1,288
Commercial real estate loans | Office, retail, and industrial
Financing Receivable, Modifications [Line Items]
Accruing		155	164
Non-accrual	[1]	4,733	0
Total		4,888	164
Commercial real estate loans | Multi-family
Financing Receivable, Modifications [Line Items]
Accruing		586	598
Non-accrual	[1]	168	186
Total		754	784
Commercial real estate loans | Construction
Financing Receivable, Modifications [Line Items]
Accruing		0	0
Non-accrual	[1]	0	0
Total		0	0
Commercial real estate loans | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Accruing		268	340
Non-accrual	[1]	48	0
Total		316	340
Total corporate loans
Financing Receivable, Modifications [Line Items]
Accruing		1,290	1,396
Non-accrual	[1]	5,099	1,236
Total		6,389	2,632
Consumer loans
Financing Receivable, Modifications [Line Items]
Accruing		1,001	1,347
Non-accrual	[1]	1,198	1,088
Total		2,199	2,435
Consumer loans | Home equity
Financing Receivable, Modifications [Line Items]
Accruing		177	494
Non-accrual	[1]	820	667
Total		997	1,161
Consumer loans | 1-4 family mortgages
Financing Receivable, Modifications [Line Items]
Accruing		824	853
Non-accrual	[1]	378	421
Total		1,202	1,274
Consumer loans | Installment
Financing Receivable, Modifications [Line Items]
Accruing		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 For82

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - TDRs That Were Restructured $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)loan	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	3	10
Pre-Modification Recorded Investment	$ 6,205	$ 445	$ 24,619
Funds Disbursed	0	0	0
Interest and Escrow Capitalized	0	0	0
Charge-offs	1,083	0	0
Post-Modification Recorded Investment	$ 5,122	$ 445	$ 24,619
Commercial real estate loans | Office, retail, and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1		1
Pre-Modification Recorded Investment	$ 5,460		$ 417
Funds Disbursed	0		0
Interest and Escrow Capitalized	0		0
Charge-offs	1,083		0
Post-Modification Recorded Investment	$ 4,377		$ 417
Commercial real estate loans | Other commercial real estate
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1
Pre-Modification Recorded Investment	$ 745
Funds Disbursed	0
Interest and Escrow Capitalized	0
Charge-offs	0
Post-Modification Recorded Investment	$ 745
Commercial real estate loans | Multi-family
Financing Receivable, Modifications [Line Items]
Number of Loans | loan			1
Pre-Modification Recorded Investment			$ 275
Funds Disbursed			0
Interest and Escrow Capitalized			0
Charge-offs			0
Post-Modification Recorded Investment			$ 275
Consumer loans | Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan		1	1
Pre-Modification Recorded Investment		$ 120	$ 75
Funds Disbursed		0	0
Interest and Escrow Capitalized		0	0
Charge-offs		0	0
Post-Modification Recorded Investment		$ 120	$ 75
Consumer loans | 1-4 family mortgages
Financing Receivable, Modifications [Line Items]
Number of Loans | loan		2
Pre-Modification Recorded Investment		$ 325
Funds Disbursed		0
Interest and Escrow Capitalized		0
Charge-offs		0
Post-Modification Recorded Investment		$ 325
Commercial, industrial, and agricultural | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan			7
Pre-Modification Recorded Investment			$ 23,852
Funds Disbursed			0
Interest and Escrow Capitalized			0
Charge-offs			0
Post-Modification Recorded Investment			$ 23,852

Past Due Loans, Allowance For83

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - TDRs That Defaulted Within Twelve Months of the Restructured Date $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)loan	Dec. 31, 2015USD ($)loan	Dec. 31, 2014USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0	3
Recorded Investment | $	$ 119	$ 0	$ 202
Commercial, industrial, and agricultural | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0	2
Recorded Investment | $	$ 0	$ 0	$ 125
Consumer loans | Home equity
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0	1
Recorded Investment | $	$ 119	$ 0	$ 77

Past Due Loans, Allowance For84

Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - TDR Rollforward - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	$ 5,067	$ 23,608
Additions	5,122	445	$ 24,619
Ending balance	8,588	5,067	23,608
Accruing
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	2,743	3,704	23,770
Additions	0	120	804
Net (payments) advances	(120)	(774)	(1,440)
Returned to performing status	0	0	(20,656)
Net transfers (to) from non-accrual	(332)	(307)	1,226
Ending balance	2,291	2,743	3,704
Non-accrual
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	2,324	19,904	4,083
Additions	6,205	325	23,815
Net (payments) advances	(1,072)	(15,525)	1,991
Charge-offs	(1,492)	(2,687)	(8,457)
Transfers to OREO	0	0	(302)
Loans sold	0	0	0
Net transfers from (to) accruing	332	307	(1,226)
Ending balance	$ 6,297	$ 2,324	$ 19,904

Premises, Furniture, and Equi85

Premises, Furniture, and Equipment (Details) - Premises, Furniture, and Equipment - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Land	$ 18,304	$ 43,442
Premises	94,369	152,444
Furniture and equipment	105,859	90,672
Total cost	218,532	286,558
Accumulated depreciation	(140,030)	(171,708)
Net book value of premises, furniture, and equipment	78,502	114,850
Assets held-for-sale	4,075	7,428
Premises, furniture, and equipment, net	$ 82,577	$ 122,278

Premises, Furniture, and Equi86

Premises, Furniture, and Equipment (Details) - Narrative $ in Thousands		Sep. 27, 2016USD ($)renewal_optionretail_branch	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Property, Plant and Equipment [Line Items]
Aggregate cash purchase price		$ 150,300
Number of branches sold | retail_branch		55
Net book value of properties		$ 58,800
Renewal term of lease for sale-leaseback transaction		14 years
Number of lease renewal options | renewal_option		5
Pre-tax gain on sale-leaseback transaction		$ 88,000
Net gain on sale-leaseback transaction		5,500	$ 5,509	$ 0	$ 0
Deferred gain, net		82,500	81,000
Current period gain recognized on sale-leaseback transaction	[1]		1,473	0	0
First year rent expense due under sale-leaseback transaction		$ 10,500
Percentage of rent escalation under sale-leaseback transaction		1.50%
Depreciation of premises, furniture, and equipment			12,804	$ 13,367	12,224
Intangible liabilities			$ 8,093
Popular Community Bank
Property, Plant and Equipment [Line Items]
Intangible liabilities					$ 10,600
Five Year Renewal Period
Property, Plant and Equipment [Line Items]
Renewal term of lease for sale-leaseback transaction		5 years
[1]	Included as reductions to net occupancy and equipment expense in the Consolidated Statements of Income.

Premises, Furniture, and Equi87

Premises, Furniture, and Equipment (Details) - Operating Leases $ in Thousands	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Abstract]
2,017	$ 18,229
2,018	16,650
2,019	16,173
2,020	15,580
2,021	15,551
2022 and thereafter	145,095
Total minimum lease payments	$ 227,278

Premises, Furniture, and Equi88

Premises, Furniture, and Equipment (Details) - Accretion of Operating Leases $ in Thousands	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Abstract]
2,017	$ 1,180
2,018	935
2,019	685
2,020	648
2,021	648
2022 and thereafter	3,997
Total accretion	$ 8,093

Premises, Furniture, and Equi89

Premises, Furniture, and Equipment (Details) - Rental Expense - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Lease expense charged to operations		$ 11,207	$ 6,850	$ 4,669
Accretion of operating lease intangible	[1]	(1,171)	(1,144)	(453)
Accretion of deferred gain on sale-leaseback transaction	[1]	(1,473)	0	0
Rental income from premises leased to others	[1]	(527)	(606)	(541)
Net operating lease expense		$ 8,036	$ 5,100	$ 3,675
[1]	Included as reductions to net occupancy and equipment expense in the Consolidated Statements of Income.

Goodwill and Other Intangible90

Goodwill and Other Intangible Assets (Details) - Changes in Carrying Amount of Goodwill - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Beginning balance	$ 319,007	$ 310,589	$ 264,062
Acquisitions	21,872	8,418	46,527
Ending balance	$ 340,879	$ 319,007	$ 310,589

Goodwill and Other Intangible91

Goodwill and Other Intangible Assets (Details) - Core Deposit Intangibles - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-lived Intangible Assets [Roll Forward]
Balance at the beginning of the year, gross	$ 48,550	$ 47,970	$ 33,775
Balance at the beginning of the year, accumulated amortization	28,280	24,360	21,471
Balance at the beginning of the year, net	20,270	23,610	12,304
Additions	10,409	580	14,195
Amortization expense	(4,682)	(3,920)	(2,889)
Balance at the end of the year, gross	58,959	48,550	47,970
Balance at the end of the year, accumulated amortization	32,962	28,280	24,360
Balance at the end of the year, net	$ 25,997	$ 20,270	$ 23,610
Weighted-average remaining life (in years)	7 years 6 months 20 days	7 years 5 months 9 days	8 years
Minimum
Finite-lived Intangible Assets [Roll Forward]
Estimated useful lives (in years)	7 months	9 months 6 days	3 months 6 days
Maximum
Finite-lived Intangible Assets [Roll Forward]
Estimated useful lives (in years)	9 years 3 months	10 years	10 years 3 months 6 days

Goodwill and Other Intangible92

Goodwill and Other Intangible Assets (Details) - Amortization of Other Intangible Assets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
2,017	$ 4,161
2,018	3,237
2,019	3,172
2,020	3,121
2,021	3,045
2022 and thereafter	9,261
Total	$ 25,997	$ 20,270	$ 23,610	$ 12,304

Deposits (Details) - Summary of

Deposits (Details) - Summary of Deposits - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deposits [Abstract]
Demand deposits	$ 2,766,748	$ 2,414,454
Savings deposits	1,615,833	1,547,587
NOW accounts	1,675,421	1,456,175
Money market deposits	1,577,316	1,526,056
Time deposits less than $100,000	755,558	754,576
Time deposits greater than $100,000	437,727	398,890
Total deposits	$ 8,828,603	$ 8,097,738

Deposits (Details) - Maturities

Deposits (Details) - Maturities of Time Deposits $ in Thousands	Dec. 31, 2016USD ($)
Deposits [Abstract]
2,017	$ 679,232
2,018	167,265
2,019	106,690
2,020	118,347
2,021	121,385
2022 and thereafter	366
Total	$ 1,193,285

Borrowed Funds (Details) - Summ

Borrowed Funds (Details) - Summary of Borrowed Funds - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
Securities sold under agreements to repurchase	$ 129,008	$ 155,196
FHLB advances	750,000	9,900
Total borrowed funds	$ 879,008	$ 165,096

Borrowed Funds (Details) - Narr

Borrowed Funds (Details) - Narrative - USD ($)	Sep. 27, 2016	Dec. 31, 2016
Short-term Debt [Line Items]
Line of credit maximum borrowing capacity	$ 50,000,000
Line of credit unused facility fee		0.35%
Line of credit amount outstanding		$ 0
One-Month LIBOR Plus 1.75%
Short-term Debt [Line Items]
Line of credit interest rate spread	1.75%
FHLB Advances
Short-term Debt [Line Items]
FHLB maturity date range, start		Jan. 9, 2017
FHLB maturity date range, end		Mar. 1, 2017
FHLB Advances | Minimum
Short-term Debt [Line Items]
FHLB fixed interest rate		0.49%
FHLB Advances | Maximum
Short-term Debt [Line Items]
FHLB fixed interest rate		0.70%

Borrowed Funds (Details) - Unus

Borrowed Funds (Details) - Unused Short-Term Credit Lines Available for Use - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
FRBs Discount Window Primary Credit Program
Line of Credit Facility [Line Items]
Amount outstanding	$ 629,699	$ 655,745
Available federal funds lines
Line of Credit Facility [Line Items]
Amount outstanding	632,000	659,000
Correspondent bank line of credit
Line of Credit Facility [Line Items]
Amount outstanding	$ 50,000	$ 0

Senior and Subordinated Debt (D

Senior and Subordinated Debt (Details) - Senior and Subordinated Debt - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Nov. 22, 2016	Sep. 29, 2016	Apr. 01, 2016
Debt Instrument [Line Items]
Senior notes		$ 0	$ 114,891
Subordinated notes		146,573	38,499
Total junior subordinated debentures		48,030	47,818
Senior and subordinated debt		194,603	201,208
Great Lakes Statutory Trust II (GLST II)
Debt Instrument [Line Items]
Debt instrument, unamortized discount		1,800	1,900
Great Lakes Statutory Trust III (GLST III)
Debt Instrument [Line Items]
Debt instrument, unamortized discount		$ 2,400	$ 2,500
Senior notes
Debt Instrument [Line Items]
Issuance date		Nov. 22, 2011
Maturity date		Nov. 22, 2016
Interest rate			5.875%	5.875%
Senior notes				$ 115,000
Subordinated notes due in 2026
Debt Instrument [Line Items]
Issuance date		Sep. 29, 2016
Maturity date		Sep. 29, 2026
Interest rate		5.875%			5.875%
Subordinated notes		$ 146,573	$ 0
Subordinated notes due in 2016
Debt Instrument [Line Items]
Issuance date		Mar. 1, 2006
Maturity date		Apr. 1, 2016
Interest rate			5.85%			5.85%
Subordinated notes		$ 0	$ 38,499			$ 38,500
Junior Subordinated Debentures, First Midwest Capital Trust I | First Midwest Capital Trust I (FMCT)
Debt Instrument [Line Items]
Issuance date		Nov. 11, 2003
Maturity date		Dec. 1, 2033
Interest rate		6.95%	6.95%
Total junior subordinated debentures		$ 37,800	$ 37,799
Junior Subordinated Debentures, Great Lakes Statutory Trust II | Great Lakes Statutory Trust II (GLST II)
Debt Instrument [Line Items]
Issuance date	[1]	Dec. 15, 2005
Maturity date	[1]	Dec. 15, 2035
Basis spread on variable interest rate	[1],[2]	1.40%	1.40%
Total junior subordinated debentures	[1]	$ 4,391	$ 4,296
Junior Subordinated Debentures, Great Lakes Statutory Trust III | Great Lakes Statutory Trust III (GLST III)
Debt Instrument [Line Items]
Issuance date	[1]	Jun. 15, 2007
Maturity date	[1]	Sep. 15, 2037
Basis spread on variable interest rate	[1],[2]	1.70%	1.70%
Total junior subordinated debentures	[1]	$ 5,839	$ 5,723
[1]	The junior subordinated debentures related to GLST II and GLST III were assumed by the Company through the Great Lakes acquisition. As of December 31, 2016, these amounts include acquisition adjustments which resulted in a discount of $1.8 million to GLST II and $2.4 million to GLST III. The acquisition adjustments totaled $1.9 million and $2.5 million to GLST II and GLST III, respectively, as of December 31, 2015.
[2]	The interest rates are a variable rate based on the three-month LIBOR plus 1.400% and 1.700% for GLST II and GLST III, respectively.

Senior and Subordinated Debt 99

Senior and Subordinated Debt (Details) - Narrative - USD ($)	Sep. 29, 2016	Dec. 31, 2016	Nov. 22, 2016	Apr. 01, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Subordinated notes		$ 146,573,000			$ 38,499,000
Senior notes		0			114,891,000
Subordinated notes due in 2016
Debt Instrument [Line Items]
Subordinated notes		0		$ 38,500,000	$ 38,499,000
Interest rate				5.85%	5.85%
Senior notes
Debt Instrument [Line Items]
Interest rate			5.875%		5.875%
Senior notes			$ 115,000,000
Subordinated notes due in 2026
Debt Instrument [Line Items]
Subordinated notes		$ 146,573,000			$ 0
Interest rate	5.875%	5.875%
Debt instrument, face amount	$ 150,000,000
Proceeds from issuance of debt	$ 146,500,000

Material Transactions Affect100

Material Transactions Affecting Stockholders' Equity (Details) - $ / shares	Mar. 08, 2016	Dec. 02, 2014	May 21, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01				$ 0.01
Common stock, increase shares authorized (in shares)			50,000,000
Common stock and Preferred stock, shares authorized (in shares)			151,000,000
Preferred stock, shares authorized (in shares)			1,000,000	1,000,000				1,000,000
Common stock, shares authorized (in shares)			150,000,000	150,000,000				150,000,000
Common dividends declared per common share (in dollars per share)				$ 0.09	$ 0.09	$ 0.09	$ 0.09	$ 0.09	$ 0.09	$ 0.09	$ 0.09	$ 0.08	$ 0.08	$ 0.08	$ 0.07
NI Bancshares Corporation
Class of Stock [Line Items]
Common stock, shares issued (in shares)	3,042,494
Shares issued (in dollars per share)	$ 18.059
Great Lakes Financial Resources, Inc.
Class of Stock [Line Items]
Common stock, shares issued (in shares)		2,440,754
Shares issued (in dollars per share)		$ 15.737

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - Basic and Diluted EPS - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income		$ 92,349	$ 82,064	$ 69,306
Net income applicable to non-vested restricted shares		(1,043)	(882)	(836)
Net income applicable to common shares		$ 91,306	$ 81,182	$ 68,470
Weighted-average common shares outstanding:
Weighted-average common shares outstanding (basic) (in shares)		79,797	77,059	74,484
Dilutive effect of common stock equivalents (in shares)		13	13	12
Weighted-average diluted common shares outstanding (in shares)		79,810	77,072	74,496
Basic EPS (in dollars per share)		$ 1.14	$ 1.05	$ 0.92
Diluted EPS (in dollars per share)		$ 1.14	$ 1.05	$ 0.92
Anti-dilutive shares not included in the computation of diluted EPS (in shares)	[1]	494	800	1,198
[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.

Income Taxes (Details) - Compon

Income Taxes (Details) - Components of Income Tax Benefit - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income tax expense (benefit):
Federal	$ 46,748	$ 18,524	$ 16,343
State	790	2,326	(1,388)
Total	47,538	20,850	14,955
Deferred income tax (benefit) expense:
Federal	(7,786)	12,048	7,901
State	6,419	4,849	8,314
Total	(1,367)	16,897	16,215
Total income tax expense	$ 46,171	$ 37,747	$ 31,170

Income Taxes (Details) - Com103

Income Taxes (Details) - Components of Effective Tax Rate - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	$ 48,482	$ 41,934	$ 35,167
Statutory federal income tax rate (percent of pretax income)	35.00%	35.00%	35.00%
Tax-exempt income, net of interest expense disallowance	$ (5,439)	$ (6,752)	$ (7,520)
Tax-exempt income, net of interest expense disallowance (percent of pretax income)	(3.90%)	(5.60%)	(7.50%)
State income tax, net of federal income tax effect	$ 4,323	$ 4,665	$ 4,503
State income tax, net of federal income tax effect (percent of pretax income)	3.10%	3.90%	4.50%
Other	$ (1,195)	$ (2,100)	$ (980)
Other (percent of pretax income)	(0.90%)	(1.80%)	(1.00%)
Total income tax expense	$ 46,171	$ 37,747	$ 31,170
Effective tax rate	33.30%	31.50%	31.00%

Income Taxes (Details) - Narrat

Income Taxes (Details) - Narrative - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Acquired thrift's tax bad debt reserve	$ 2,500	$ 2,500	$ 2,500
Deferred tax assets, net	100,207	86,693
Unrecognized tax benefit that would affect effective tax rate	1,400	936,000	$ 597,000
NIBancsharesandPeoplesBankAcquisitionsMember [Member]
Income Taxes [Line Items]
Deferred tax assets, net	$ 4,400
Peoples' Bank and Great Lakes Acquisitions [Member]
Income Taxes [Line Items]
Deferred tax assets, net		$ 3,500

Income Taxes (Details) - Deferr

Income Taxes (Details) - Deferred Tax Assets And Liabilities - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Allowance for credit losses	$ 30,399	$ 26,131
Deferred gain on sale-leaseback transaction	28,133	0
Unrealized losses on securities	18,320	18,328
Non-equity based compensation	6,060	3,739
Equity based compensation	5,228	5,469
OREO	4,336	2,597
Federal and state net operating loss (NOL) carryforwards	388	7,679
Alternative minimum tax (AMT) and other credit carryforwards	90	17,739
Property valuation adjustments	0	3,003
Other	10,997	8,375
Total deferred tax assets	103,951	93,060
Deferred tax liabilities:
Acquisition adjustments	(13,407)	(9,371)
Accrued retirement benefits	(6,281)	(6,065)
Deferred loan fees and costs	(3,172)	(2,432)
Cancellation of indebtedness income	(2,136)	(3,204)
Other	(6,442)	(5,039)
Total deferred tax liabilities	(31,438)	(26,111)
Deferred tax valuation allowance	0	0
Net deferred tax assets	72,513	66,949
Tax effect of adjustments related to other comprehensive (loss) income	27,694	19,744
Net deferred tax assets including adjustments	100,207	86,693
NOL carryforwards available to offset future taxable income:
AMT credits	0	17,739
Internal Revenue Service (IRS)
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	574	922
Illinois
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	26,342	160,016
Indiana
NOL carryforwards available to offset future taxable income:
Gross NOL Carryforwards	$ 1,003	$ 11,796

Income Taxes (Details) - Rollfo

Income Taxes (Details) - Rollforward of Unrecognized Tax Benefits - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance		$ 1,408	$ 912	$ 279
Additions for tax positions relating to the current year		640	480	635
Additions for tax positions relating to prior years		0	37	0
Reductions for tax positions relating to prior years		(9)	(21)	(2)
Ending balance		2,039	1,408	912
Interest and penalties not included above:
Interest expense, net of tax effect, and penalties	[1]	49	20	4
Accrued interest and penalties, net of tax effect, at end of year	[1]	$ 73	$ 24	$ 4
[1]	Included in income tax expense in the Consolidated Statements of Income.

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - Narrative	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan, employer matching contribution percent of employee's compensation			4.00%	2.00%
Defined contribution plan, transition contribution in next fiscal year (up to) (percent)		4.00%
Defined contribution plan, discretionary contribution vesting period	6 years
Actuarial losses as a percentage of accumulated benefit obligation	41.30%	39.40%
Pension Plan
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Actuarial losses as a percentage of accumulated benefit obligation	10.00%
Contributions
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan, employee contribution limit, percentage of compensation			100.00%	45.00%
Certain Highly Compensated Employees
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan, employee contribution limit, percentage of compensation				15.00%
Voluntary 401K Plans
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan, employer automatic contribution limit	2.00%
Deferred Profit Sharing
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined contribution plan, employer automatic contribution limit	15.00%

Employee Benefit Plans (Deta108

Employee Benefit Plans (Details) - Profit Sharing Plan - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Profit sharing expense		$ 33,309	$ 31,852	$ 27,245
Profit Sharing Expense
Defined Contribution Plan Disclosure [Line Items]
Profit sharing expense	[1]	6,171	6,919	6,354
Company dividends received by the Profit Sharing Plan		$ 494	$ 466	$ 428
Company shares held by the Profit Sharing Plan at the end of the year:
Number of shares		1,175,858	1,277,567	1,364,558
Fair value		$ 29,667	$ 23,546	$ 23,348
[1]	Included in retirement and other employee benefits in the Consolidated Statements of Income

Employee Benefit Plans (Deta109

Employee Benefit Plans (Details) - Pension Plan Cost and Obligations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Accumulated benefit obligation	$ 68,959		$ 67,185
Change in projected benefit obligation:
Beginning balance	67,185		67,283
Service cost	0		0
Interest cost	1,635		2,334	$ 2,346
Settlements	(3,136)		(7,320)
Actuarial loss	3,851		5,336
Benefits paid	(576)		(448)
Ending balance	68,959		67,185	67,283
Change in fair value of plan assets:
Beginning balance	64,903		72,193
Actual return on plan assets	3,998		478
Benefits paid	(576)		(448)
Settlements	(3,136)		(7,320)
Ending balance	65,189	[1]	64,903	$ 72,193
Funded status recognized in the Consolidated Statements of Financial Condition:
Noncurrent liability	(3,770)		(2,282)
Amounts recognized in accumulated other comprehensive loss:
Prior service cost	0		0
Net loss	28,483		26,481
Net amount recognized	$ 28,483		$ 26,481
Actuarial losses included in accumulated other comprehensive loss as a percent of:
Accumulated benefit obligation	41.30%		39.40%
Fair value of plan assets	43.70%		40.80%
Amounts expected to be amortized from accumulated other comprehensive loss into net periodic benefit cost in the next fiscal year:
Prior service cost	$ 0		$ 0
Net loss	582		516
Net amount expected to be recognized	$ 582		$ 516
Weighted-average assumptions at the end of the year used to determine the actuarial present value of the projected benefit obligation:
Discount rate	3.86%		3.99%
[1]	Additional information regarding the fair value of Pension Plan assets as of December 31, 2016 can be found in Note 22, "Fair Value."

Employee Benefit Plans (Deta110

Employee Benefit Plans (Details) - Net Periodic Benefit Pension Expense - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of net periodic benefit cost:
Interest cost	$ 1,635	$ 2,334	$ 2,346
Expected return on plan assets	(4,057)	(4,333)	(4,931)
Recognized net actuarial loss	571	367	249
Amortization of prior service cost	0	0	0
Recognized settlement loss	1,338	2,254	1,377
Net periodic (income) cost	(513)	622	(959)
Other changes in plan assets and benefit obligations recognized as a charge to other comprehensive (loss) income:
Net loss for the period	(3,911)	(9,191)	(10,752)
Amortization of net loss	1,909	2,621	1,625
Total unrealized loss	(2,002)	(6,570)	(9,127)
Total recognized in net periodic pension cost and other comprehensive (loss) income	$ (1,489)	$ (7,192)	$ (8,168)
Weighted-average assumptions used to determine the net periodic cost:
Discount rate	3.99%	3.60%	4.30%
Expected return on plan assets	6.50%	6.50%	7.25%

Employee Benefit Plans (Deta111

Employee Benefit Plans (Details) - Pension Plan Asset Allocation - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Asset Category:
Fair Value of Plan Assets (in dollars)		$ 65,189	[1]	$ 64,903	$ 72,193
Percentage of Plan Assets		100.00%		100.00%
Equity securities
Asset Category:
Target Plan Asset Allocations, minimum		50.00%
Target Plan Asset Allocations, maximum		60.00%
Fair Value of Plan Assets (in dollars)	[1]	$ 38,910
Percentage of Plan Assets		60.00%		59.00%
Fixed income
Asset Category:
Target Plan Asset Allocations, minimum		30.00%
Target Plan Asset Allocations, maximum		48.00%
Fair Value of Plan Assets (in dollars)	[1]	$ 21,405
Percentage of Plan Assets		33.00%		35.00%
Cash equivalents
Asset Category:
Target Plan Asset Allocations, minimum		2.00%
Target Plan Asset Allocations, maximum		10.00%
Fair Value of Plan Assets (in dollars)	[1]	$ 4,874
Percentage of Plan Assets		7.00%		6.00%
[1]	Additional information regarding the fair value of Pension Plan assets as of December 31, 2016 can be found in Note 22, "Fair Value."

Employee Benefit Plans (Deta112

Employee Benefit Plans (Details) - Estimated Future Pension Benefit Payments $ in Thousands	Dec. 31, 2016USD ($)
Compensation and Retirement Disclosure [Abstract]
2,017	$ 16,009
2,018	5,308
2,019	5,059
2,020	4,747
2,021	4,646
2022-2026	$ 18,583

Share-Based Compensation (Detai

Share-Based Compensation (Details) - Narrative - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Directors Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term	10 years
Granted (in shares)	18,000	14,000
Directors Plan | Accelerated Grant Date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Nonqualified Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term	10 years
Stock options granted in period (in shares)	0	0	0
Stock options exercised in period (in shares)	0	0	0
Restricted Stock And Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Granted (in shares)	494,000
Restricted Stock And Restricted Stock Unit Awards | Vesting After Two Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	50.00%
Restricted Stock And Restricted Stock Unit Awards | Vesting After Three Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	50.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of internal and external performance metric analysis	3 years
Metric weighting (percent)	50.00%
Granted (in shares)	126,000
Performance Shares | Vesting After Three Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	33.00%
Performance Shares | Vesting After Fourth Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	33.00%
Performance Shares | Vesting After Fifth Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage	33.00%
Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares earned of those granted based on performance	0.00%
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of shares earned of those granted based on performance	200.00%

Share-Based Compensation (De114

Share-Based Compensation (Details) - Shares of Common Stock Available Under Share-Based Plans	Dec. 31, 2016shares
Omnibus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized (in shares)	8,631,641
Shares Available For Grant (in shares)	1,998,949
Directors Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Authorized (in shares)	481,250
Shares Available For Grant (in shares)	101,727

Share-Based Compensation (De115

Share-Based Compensation (Details) - Nonqualified Stock Option Transactions $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Number of Options
Options outstanding beginning balance | shares	756
Expired | shares	(270)
Options outstanding ending balance | shares	486
Exercisable at the end of the year | shares	486
Weighted Average Exercise Price
Options outstanding beginning balance (in dollars per share) | $ / shares	$ 32.55
Expired (in dollars per share) | $ / shares	33.95
Options outstanding ending balance (in dollars per share) | $ / shares	31.77
Exercisable at the end of the year (in dollars per share) | $ / shares	$ 31.77
Weighted average remaining contractual term of options outstanding ending balance (in years)	11 months 10 days	[1]
Weighted average remaining contractual term of options exercisable at the end of the year (in years)	11 months 10 days	[1]
Aggregate intrinsic value of options outstanding at the end of the year | $	$ 558	[2]
Aggregate intrinsic value of options exercisable at the end of the year | $	$ 558	[2]
[1]	Represents the average remaining contractual life in years.
[2]	Aggregate intrinsic value represents the total pre-tax intrinsic value that would have been received by the option holders if they had exercised their options on December 31, 2016. Intrinsic value equals the difference between the Company's average of the high and low stock price on the last trading day of the year and the option exercise price, multiplied by the number of shares. This amount will fluctuate with changes in the fair value of the Company's common stock.

Share-Based Compensation (De116

Share-Based Compensation (Details) - Restricted Stock Award Transactions shares in Thousands	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Restricted Stock/Unit Awards
Number of Shares/Units
Non-vested awards at beginning of year (in shares)	908
Granted (in shares)	494
Vested (in shares)	(351)
Forfeited (in shares)	(62)
Non-vested awards at end of year (in shares)	989
Weighted Average Grant Date Fair Value
Non-vested awards at beginning of year (in dollars per share) | $ / shares	$ 15.92
Vested (in dollars per share) | $ / shares	14.69
Forfeited (in dollars per share) | $ / shares	16.72
Non-vested awards at end of year (in dollars per share) | $ / shares	$ 16.95
Performance Shares
Number of Shares/Units
Non-vested awards at beginning of year (in shares)	338
Granted (in shares)	126
Vested (in shares)	(31)
Forfeited (in shares)	(25)
Non-vested awards at end of year (in shares)	408
Weighted Average Grant Date Fair Value
Non-vested awards at beginning of year (in dollars per share) | $ / shares	$ 15.19
Granted (in dollars per share) | $ / shares	17.28
Vested (in dollars per share) | $ / shares	14.69
Forfeited (in dollars per share) | $ / shares	16.72
Non-vested awards at end of year (in dollars per share) | $ / shares	$ 15.78

Share-Based Compensation (De117

Share-Based Compensation (Details) - Other Restricted Stock Award/Unit Information - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit realized from the vesting/release of restricted stock and restricted stock unit awards	$ 3,152	$ 2,962	$ 2,424
Restricted Stock Restricted Stock Unit and Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of restricted stock, restricted stock unit, and performance share awards granted during the year (in dollars per share)	$ 17.28	$ 16.95	$ 16.13
Restricted Stock And Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted stock and restricted stock unit awards vested during the year	$ 12,231	$ 7,615	$ 7,546
Income tax benefit realized from the vesting/release of restricted stock and restricted stock unit awards	$ 2,529	$ 2,368	$ 2,939

Share-Based Compensation (De118

Share-Based Compensation (Details) - Effect of Recording Share-Based Compensation Expense - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation expense	[1]	$ 7,879	$ 7,242	$ 5,926
Income tax benefit		3,152	2,962	2,424
Share-based compensation expense, net of tax		4,727	4,280	3,502
Unrecognized compensation expense		$ 9,990	$ 8,644	$ 6,937
Weighted-average amortization period remaining (in years)		1 year 4 months	1 year 4 months 7 days	1 year 3 months 18 days
[1]	Comprised of restricted stock, restricted stock unit, and performance share awards expense.

Stockholder Rights Plan (Detail

Stockholder Rights Plan (Details) - $ / shares	Nov. 15, 2015	Feb. 15, 1989
Rights Agreement Expired November 15, 2015
Class of Warrant or Right [Line Items]
Number of securities called by each warrant or right		1
Series A Preferred Stock
Class of Warrant or Right [Line Items]
Exercise price of warrants or rights (in dollars per share)	$ 150
Series A Preferred Stock | Rights Agreement Expired November 15, 2015
Class of Warrant or Right [Line Items]
Number of securities called by each warrant or right	0.01

Regulatory and Capital Matte120

Regulatory and Capital Matters (Details) - Narrative - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2015
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash reserve balance	$ 85,400,000	$ 66,900,000
Adjustment to available dividends	32,800,000
Regulatory capital requirements under banking regulations, inclusion of trust-preferred securities in Tier One capital calculation (less than)	15,000,000,000
Trust-preferred securities included in Tier 1 capital	$ 50,700,000
Tier 1 risk based capital conservation buffer initial requirements phasing duration	4 years
Implementation of deductions and other adjustments to CET1, percentage			40.00%
Implementation of deductions and other adjustments to CET1 additional, percentage	20.00%
Risk weighted threshold of items deducted from CET1 capital	10.00%
Aggregate risk weighted threshold of items deducted from CET1	15.00%
Minimum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Risk-weighting	0.00%
Maximum
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Risk-weighting	600.00%
January 2,019
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Minimum ratio of CET1 to risk-weighted assets	4.50%
Capital conservation buffer	2.50%
Resulting minimum ratio of CET1 to risk-weighted assets after capital conversion buffer	7.00%
Minimum ratio of Tier 1 capital to risk-weighted assets	6.00%
Minimum ratio of Tier 1 capital to risk-weighted assets, adjusted	8.50%
Minimum ratio of Total capital to risk-weighted assets	8.00%
Minimum ratio of Total capital to risk-weighted assets, adjusted	10.50%
Minimum leverage ratio	4.00%

Regulatory and Capital Matte121

Regulatory and Capital Matters (Details) - Summary of Capital Ratios - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
First Midwest Bancorp, Inc.
Total capital to risk-weighted assets:
Actual Capital	$ 1,225,529	$ 968,331
Actual Ratio (percent)	12.23%	11.15%
Adequately Capitalized Capital	$ 864,176	$ 695,029
Adequately Capitalized Ratio (percent)	8.625%	8.00%
Tier 1 capital to risk-weighted assets:
Actual Capital	$ 991,873	$ 893,476
Actual Ratio (percent)	9.90%	10.28%
Adequately Capitalized Capital	$ 663,788	$ 521,272
Adequately Capitalized Ratio (percent)	6.625%	6.00%
Common equity Tier 1 to risk-weighted assets:
Actual Capital	$ 941,315	$ 845,640
Actual Ratio (percent)	9.39%	9.73%
Adequately Capitalized Capital	$ 513,496	$ 390,954
Adequately Capitalized Ratio (percent)	5.125%	4.50%
Tier 1 capital to average assets:
Actual Capital	$ 991,873	$ 893,476
Actual Ratio (percent)	8.99%	9.40%
Adequately Capitalized Capital	$ 441,473	$ 380,043
Adequately Capitalized Ratio (percent)	4.00%	4.00%
First Midwest Bank
Total capital to risk-weighted assets:
Actual Capital	$ 1,043,482	$ 929,167
Actual Ratio (percent)	10.73%	11.02%
Adequately Capitalized Capital	$ 838,741	$ 674,380
Adequately Capitalized Ratio (percent)	8.625%	8.00%
To Be Well-Capitalized Under Prompt Corrective Action Provisions Capital	$ 972,454	$ 842,974
To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	10.00%	10.00%
Tier 1 capital to risk-weighted assets:
Actual Capital	$ 956,399	$ 854,322
Actual Ratio (percent)	9.83%	10.13%
Adequately Capitalized Capital	$ 644,251	$ 505,785
Adequately Capitalized Ratio (percent)	6.625%	6.00%
To Be Well-Capitalized Under Prompt Corrective Action Provisions Capital	$ 777,963	$ 674,380
To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	8.00%	8.00%
Common equity Tier 1 to risk-weighted assets:
Actual Capital	$ 956,399	$ 854,322
Actual Ratio (percent)	9.83%	10.13%
Adequately Capitalized Capital	$ 498,383	$ 379,338
Adequately Capitalized Ratio (percent)	5.125%	4.50%
To Be Well-Capitalized Under Prompt Corrective Action Provisions Capital	$ 632,095	$ 547,933
To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio ( percent)	6.50%	6.50%
Tier 1 capital to average assets:
Actual Capital	$ 956,399	$ 854,322
Actual Ratio (percent)	8.76%	9.09%
Adequately Capitalized Capital	$ 436,560	$ 375,950
Adequately Capitalized Ratio (percent)	4.00%	4.00%
To Be Well-Capitalized Under Prompt Corrective Action Provisions Capital	$ 545,700	$ 469,937
To Be Well-Capitalized Under Prompt Corrective Action Provisions Ratio (percent)	5.00%	5.00%

Derivative Instruments and H122

Derivative Instruments and Hedging Activities (Details) - Fair Value Hedges - Fair Value Hedging - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross notional amount outstanding		$ 5,958	$ 11,620
Derivative liability fair value		$ (282)	$ (643)
Weighted-average interest rate received		2.63%	2.25%
Weighted-average interest rate paid		5.96%	6.36%
Weighted-average maturity (in years)		1 year 10 months 1 day	1 year 11 months 19 days
Fair value of derivative	[1]	$ 296	$ 665
[1]	This amount represents the fair value if credit risk related contingent features were triggered.

Derivative Instruments and H123

Derivative Instruments and Hedging Activities (Details) - Narrative - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest rate cash flow hedge gain (loss) to be reclassified during the next 12 months, net	$ 3,900
Capital market products income	$ 10,024	$ 4,806	$ 2,231
Portion of fair value outstanding, interest rate swaps covered by collateral agreements (percent)	100.00%	100.00%
Cash Flow Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of variable rate loans hedged using interest rate swaps	$ 735,000
Amount hedged of borrowed funds using forward starting interest rate swaps	$ 735,000
Forward starting interest rate swaps				$ 325,000

Derivative Instruments and H124

Derivative Instruments and Hedging Activities (Details) - Cash Flow Hedges - Cash Flow Hedging - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross notional amount outstanding	$ 1,470,000	$ 1,220,000
Derivative asset fair value	5,402	4,787
Derivative liability fair value	$ (7,390)	$ (8,950)
Weighted-average interest rate received	1.37%	1.24%
Weighted-average interest rate paid	1.11%	0.75%
Weighted-average maturity (in years)	2 years 9 months 28 days	3 years 10 months 28 days

Derivative Instruments and H125

Derivative Instruments and Hedging Activities (Details) - Other Derivative Instruments - Other Derivative Instruments - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Gross notional amount outstanding		$ 1,656,612	$ 853,385
Derivative asset fair value		13,478	11,446
Derivative liability fair value		(13,478)	(11,446)
Fair value of derivative	[1]	$ 13,753	$ 11,939
[1]	This amount represents the fair value if credit risk related contingent factors were triggered.

Derivative Instruments and H126

Derivative Instruments and Hedging Activities (Details) - Offsetting Derivatives - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Assets
Gross amounts recognized		$ 18,880	$ 16,233
Less: amounts offset in the Consolidated Statements of Financial Condition		0	0
Net amount presented in the Consolidated Statements of Financial Condition	[1]	18,880	16,233
Offsetting derivative positions		(10,889)	(4,791)
Cash collateral pledged		0	0
Net credit exposure		7,991	11,442
Liabilities
Gross amounts recognized		21,150	21,039
Less: amounts offset in the Consolidated Statements of Financial Condition		0	0
Net amount presented in the Consolidated Statements of Financial Condition	[1]	21,150	21,039
Offsetting derivative positions		(10,889)	(4,791)
Cash collateral pledged		(10,261)	(16,248)
Net credit exposure		$ 0	$ 0
[1]	Included in other assets or other liabilities in the Consolidated Statements of Financial Condition.

Commitments, Guarantees, and127

Commitments, Guarantees, and Contingent Liabilities (Details) - Contractual or Notional Amounts of Financial Instruments - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Other Commitments [Line Items]
Letters of credit		$ 100,430	$ 100,610
Recourse on assets sold:
Unpaid principal balance of loans sold		187,158	196,389
Carrying value of recourse obligation	[1]	142	87
Commitments to extend credit
Other Commitments [Line Items]
Commercial, industrial, and agricultural		1,522,152	1,303,056
Commercial real estate		397,423	366,250
Home equity		426,384	352,114
Other commitments	[2]	214,943	203,121
Total commitments to extend credit		$ 2,560,902	$ 2,224,541
[1]	Included in other liabilities in the Consolidated Statements of Financial Condition.
[2]	Other commitments includes installment and overdraft protection program commitments.

Fair Value (Details) - Recurrin

Fair Value (Details) - Recurring Fair Value Measurements - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Trading securities:
Total trading securities		$ 17,920	$ 16,894
Securities available-for-sale:
Securities available-for-sale, at fair value		1,919,450	1,306,636
Mortgage servicing rights (MSRs)		6,120	1,853	$ 1,728	$ 1,893
U.S. treasury securities
Securities available-for-sale:
Securities available-for-sale, at fair value		48,541	16,980
U.S. agency securities
Securities available-for-sale:
Securities available-for-sale, at fair value		183,637	86,643
CMOs
Securities available-for-sale:
Securities available-for-sale, at fair value		1,047,446	687,185
MBSs
Securities available-for-sale:
Securities available-for-sale, at fair value		332,655	153,530
Municipal securities
Securities available-for-sale:
Securities available-for-sale, at fair value		270,846	327,570
CDOs
Securities available-for-sale:
Securities available-for-sale, at fair value		33,260	31,529
Equity securities
Securities available-for-sale:
Securities available-for-sale, at fair value		3,065	3,199
Recurring | Level 1
Trading securities:
Money market funds		1,645	2,530
Mutual funds		16,275	14,364
Total trading securities		17,920	16,894
Securities available-for-sale:
Securities available-for-sale, at fair value		48,541	16,980
Mortgage servicing rights (MSRs)	[1]	0	0
Derivative assets	[1]	0	0
Liabilities:
Derivative liabilities	[2]	0	0
Recurring | Level 1 | U.S. treasury securities
Securities available-for-sale:
Securities available-for-sale, at fair value		48,541	16,980
Recurring | Level 1 | U.S. agency securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 1 | CMOs
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 1 | MBSs
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 1 | Municipal securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 1 | CDOs
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 1 | Equity securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 2
Trading securities:
Money market funds		0	0
Mutual funds		0	0
Total trading securities		0	0
Securities available-for-sale:
Securities available-for-sale, at fair value		1,837,649	1,258,127
Mortgage servicing rights (MSRs)	[1]	0	0
Derivative assets	[1]	18,880	16,233
Liabilities:
Derivative liabilities	[2]	21,150	21,039
Recurring | Level 2 | U.S. treasury securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 2 | U.S. agency securities
Securities available-for-sale:
Securities available-for-sale, at fair value		183,637	86,643
Recurring | Level 2 | CMOs
Securities available-for-sale:
Securities available-for-sale, at fair value		1,047,446	687,185
Recurring | Level 2 | MBSs
Securities available-for-sale:
Securities available-for-sale, at fair value		332,655	153,530
Recurring | Level 2 | Municipal securities
Securities available-for-sale:
Securities available-for-sale, at fair value		270,846	327,570
Recurring | Level 2 | CDOs
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 2 | Equity securities
Securities available-for-sale:
Securities available-for-sale, at fair value		3,065	3,199
Recurring | Level 3
Trading securities:
Money market funds		0	0
Mutual funds		0	0
Total trading securities		0	0
Securities available-for-sale:
Securities available-for-sale, at fair value		33,260	31,529
Mortgage servicing rights (MSRs)	[1]	6,120	1,853
Derivative assets	[1]	0	0
Liabilities:
Derivative liabilities	[2]	0	0
Recurring | Level 3 | U.S. treasury securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 3 | U.S. agency securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 3 | CMOs
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 3 | MBSs
Securities available-for-sale:
Securities available-for-sale, at fair value		0	0
Recurring | Level 3 | Municipal securities
Securities available-for-sale:
Securities available-for-sale, at fair value		0
Recurring | Level 3 | CDOs
Securities available-for-sale:
Securities available-for-sale, at fair value		33,260	31,529
Recurring | Level 3 | Equity securities
Securities available-for-sale:
Securities available-for-sale, at fair value		$ 0	$ 0
[1]	Included in other assets in the Consolidated Statements of Financial Condition.
[2]	Included in other liabilities in the Consolidated Statements of Financial Condition.

Fair Value (Details) - Signific

Fair Value (Details) - Significant Unobservable Inputs Used In The Valuation of CDOs - CDOs	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Probability of prepayment	0.00%	1.80%
Probability of default	16.70%	19.10%
Loss given default	93.30%	93.80%
Probability of deferral cure	7.60%	15.20%
Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Probability of prepayment	10.90%	15.10%
Probability of default	46.80%	32.60%
Loss given default	98.90%	97.10%
Probability of deferral cure	100.00%	63.10%

Fair Value (Details) - Rollforw

Fair Value (Details) - Rollforward of Carrying Value of CDOs $ in Thousands		12 Months Ended
		Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)security
Rollforward of the Carrying Value of CDOs
Carrying Value Of CDOs Sold	[1]	$ 0	$ 171	$ 8,934
CDOs
Rollforward of the Carrying Value of CDOs
Beginning balance		31,529	33,774	18,309
Additions		0	0	6,549
Change in other comprehensive (loss) income	[2]	2,337	(2,030)	13,495
Paydowns and sales	[3]	(606)	(215)	(4,579)
Ending balance		$ 33,260	$ 31,529	$ 33,774
Number Of CDOs Sold | security				1
Carrying Value Of CDOs Sold				$ 1,300
Great Lakes Financial Resources, Inc. | CDOs
Rollforward of the Carrying Value of CDOs
Number Of CDOs Sold | security				4
Securities available-for-sale				$ 2,900
[1]	These reductions were driven by the sale of one CMO with a carrying value of $1.3 million during the year ended December 31, 2015 and one CDO with a carrying value of $1.3 million and one municipal security with a carrying value of $357,000 during the year ended December 31, 2014
[2]	Included in unrealized holding (losses) gains in the Consolidated Statements of Comprehensive Income.
[3]	During the year ended December 31, 2014, one CDO with a carrying value of $1.3 million and four CDOs totaling $2.9 million, which were acquired in the Great Lakes transaction, were sold.

Fair Value (Details) - Narrativ

Fair Value (Details) - Narrative - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value [Line Items]
Total amount of loans being serviced for the benefit of others at the end of the year	$ 640,530	$ 242,915	$ 220,372
Loans serviced for others	$ 305,500
Minimum
Fair Value [Line Items]
Appraisal adjustment (percent)	0.00%
Maximum
Fair Value [Line Items]
Appraisal adjustment (percent)	15.00%

Fair Value Fair Value (Details)

Fair Value Fair Value (Details) - Significant Unobservable Inputs Used in the Valuation of MSRs (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
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	7.70%	10.10%
Maturity (months)	12 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	22.80%	20.90%
Maturity (months)	103 months	86 months
Discount rate	13.00%	13.00%

Fair Value (Details) - Carrying

Fair Value (Details) - Carrying Value of Mortgage Servicing Rights - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance		$ 1,853	$ 1,728	$ 1,893
Additions from acquisition		3,092	0	0
New MSRs		1,263	342	315
Total (losses) gains included in earnings:
Changes in valuation inputs and assumptions	[1]	610	(11)	(480)
Other changes in fair value	[1],[2]	(698)	(206)	0
Ending balance		6,120	1,853	1,728
Contractual servicing fees earned during the year	[1]	1,312	546	520
Total amount of loans being serviced for the benefit of others at the end of the year		$ 640,530	$ 242,915	$ 220,372
[1]	Included in mortgage banking income in the Consolidated Statements of Income and relate to assets still held at the end of the year.
[2]	Primarily represents changes in expected future cash flows over time due to payoffs and paydowns.

Fair Value (Details) - Annual F

Fair Value (Details) - Annual Fair Value Measurements of Pension Plan Asses - USD ($) $ in Thousands		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		$ 65,189	[1]	$ 64,903	$ 72,193
Mutual fund
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	[2]	29,071		23,061
U.S. agency securities
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		13,904		12,404
Corporate bonds
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		7,010		9,569
Common stocks
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		7,526		11,330
Common trust funds
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		7,678		8,539
Level 1
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		42,554		41,257
Level 1 | Mutual fund
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	[2]	29,071		23,061
Level 1 | U.S. agency securities
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		5,957		6,866
Level 1 | Corporate bonds
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0		0
Level 1 | Common stocks
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		7,526		11,330
Level 1 | Common trust funds
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0		0
Level 2
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		22,635		23,646
Level 2 | Mutual fund
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets	[2]	0		0
Level 2 | U.S. agency securities
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		7,947		5,538
Level 2 | Corporate bonds
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		7,010		9,569
Level 2 | Common stocks
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		0		0
Level 2 | Common trust funds
Fair Value Defined Benefit Plan Disclosure [Line Items]
Pension plan assets		$ 7,678		$ 8,539
[1]	Additional information regarding the fair value of Pension Plan assets as of December 31, 2016 can be found in Note 22, "Fair Value."
[2]	Includes mutual funds, money market funds, cash, cash equivalents, and accrued interest.

Fair Value (Details) - Non-Recu

Fair Value (Details) - Non-Recurring Fair Value Measurements - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Fair Value (Details) - Assets Measured On A Non-Recurring Basis [Line Items]
OREO		$ 26,083	$ 27,782
Assets held-for-sale		4,075	7,428
Level 1 | Nonrecurring
Fair Value (Details) - Assets Measured On A Non-Recurring 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
Level 2 | Nonrecurring
Fair Value (Details) - Assets Measured On A Non-Recurring 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
Level 3 | Nonrecurring
Fair Value (Details) - Assets Measured On A Non-Recurring Basis [Line Items]
Collateral-dependent impaired loans	[1]	22,019	10,519
OREO	[2]	8,624	8,581
Loans held-for-sale	[3]	10,484	14,444
Assets held-for-sale	[4]	$ 4,075	$ 7,428
[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 (Details) - Fair Val

Fair Value (Details) - Fair Value Measurements of Other Financial Instruments - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash and due from banks	$ 155,055	$ 114,587
Interest-bearing deposits in other banks	107,093	266,615
Securities held-to-maturity	22,291	23,152
FHLB and FRB stock	59,131	39,306
Loans	8,168,062	7,088,085
Investment in BOLI	219,746	209,601
Liabilities:
Deposits	8,828,603	8,097,738
Borrowed funds	879,008	165,096
Senior and subordinated debt	194,603	201,208
Level 1
Assets:
Cash and due from banks	155,055	114,587
Level 1 | Carrying Amount
Assets:
Cash and due from banks	155,055	114,587
Level 2
Assets:
Interest-bearing deposits in other banks	107,093	266,615
Securities held-to-maturity	18,212	20,054
FHLB and FRB stock	59,131	39,306
Liabilities:
Deposits	8,820,572	8,093,640
Borrowed funds	879,008	165,096
Senior and subordinated debt	197,888	205,726
Accrued interest payable	3,416	2,175
Level 2 | Carrying Amount
Assets:
Interest-bearing deposits in other banks	107,093	266,615
Securities held-to-maturity	22,291	23,152
FHLB and FRB stock	59,131	39,306
Liabilities:
Deposits	8,828,603	8,097,738
Borrowed funds	879,008	165,096
Senior and subordinated debt	194,603	201,208
Accrued interest payable	3,416	2,175
Level 3
Assets:
Loans	7,973,845	6,959,024
Investment in BOLI	219,746	209,601
Accrued interest receivable	34,384	27,847
Other interest-earning assets	834	1,982
Level 3 | Carrying Amount
Assets:
Loans	8,172,584	7,091,988
Investment in BOLI	219,746	209,601
Accrued interest receivable	34,384	27,847
Other interest-earning assets	$ 834	$ 1,982

Related Party Transactions (Det

Related Party Transactions (Details) - Narrative	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk (percent)	5.00%	5.00%

Condensed Parent Company Fin138

Condensed Parent Company Financial Statements (Details) - Statements of Financial Condition (Parent Company Only) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and due from banks	$ 155,055	$ 114,587
Other assets	278,271	178,463
Total assets	11,422,555	9,732,676
Liabilities and Equity [Abstract]
Senior and subordinated debt	194,603	201,208
Accrued interest payable and other liabilities	263,261	122,366
Stockholders' equity	1,257,080	1,146,268	$ 1,100,775	$ 1,001,442
Total liabilities and stockholders' equity	11,422,555	9,732,676
Parent Company
Assets
Cash and due from banks	140,217	119,693
Investments in and advances to subsidiaries	1,279,065	1,194,173
Other assets	139,060	63,337
Total assets	1,558,342	1,377,203
Liabilities and Equity [Abstract]
Senior and subordinated debt	194,603	201,208
Accrued interest payable and other liabilities	106,659	29,727
Stockholders' equity	1,257,080	1,146,268
Total liabilities and stockholders' equity	$ 1,558,342	$ 1,377,203

Condensed Parent Company Fin139

Condensed Parent Company Financial Statements (Details) - Statements of Income (Parent Company Only) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income
Interest income	$ 378,332	$ 335,984	$ 299,864
Securities transactions and other	3,635	2,764	4,567
Expenses
Interest expense	28,641	24,386	23,012
Other expenses	24,834	21,601	20,135
Income before income tax expense	138,520	119,811	100,476
Income tax benefit	(46,171)	(37,747)	(31,170)
Net income	92,349	82,064	69,306
Net income applicable to non-vested restricted shares	(1,043)	(882)	(836)
Net income applicable to common shares	91,306	81,182	68,470
Parent Company
Income
Dividends from subsidiaries	86,791	127,000	56,881
Interest income	2,188	2,164	1,502
Securities transactions and other	215	584	6,451
Total income	89,194	129,748	64,834
Expenses
Interest expense	12,477	12,545	12,062
Salaries and employee benefits	16,104	14,624	12,589
Other expenses	7,110	6,003	5,867
Total expenses	35,691	33,172	30,518
Income before income tax expense	53,503	96,576	34,316
Income tax benefit	12,878	11,950	8,710
Income before equity in undistributed (loss) income of subsidiaries	66,381	108,526	43,026
Equity in undistributed income (loss) of subsidiaries	25,968	(26,462)	26,280
Net income	92,349	82,064	69,306
Net income applicable to non-vested restricted shares	(1,043)	(882)	(836)
Net income applicable to common shares	$ 91,306	$ 81,182	$ 68,470

Condensed Parent Company Fin140

Condensed Parent Company Financial Statements (Details) - Statements of Cash Flows (Parent Company Only) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net income		$ 92,349	$ 82,064	$ 69,306
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of premises, furniture, and equipment		12,804	13,367	12,224
Net securities gains		(1,420)	(2,373)	(8,097)
Share-based compensation expense	[1]	7,879	7,242	5,926
Tax expense related to share-based compensation		(685)	(1,200)	(106)
Net (increase) decrease in other assets		(76,902)	10,023	(18,015)
Net increase (decrease) in other liabilities		47,118	(1,042)	22,367
Investing Activities
Purchases of securities available-for-sale		(933,317)	(509,481)	(25,856)
Purchase of premises, furniture, and equipment		19,083	11,269	14,085
Net cash (used in) provided by investing activities		(1,049,338)	(496,834)	108,655
Financing Activities
Net proceeds from the issuance of subordinated debt		146,484	0	0
Payments for the retirement of senior and subordinated debt		(153,500)	0	0
Cash dividends paid		(29,198)	(27,036)	(22,568)
Restricted stock activity		(2,476)	(2,890)	(2,781)
Excess tax benefit related to share-based compensation		488	794	912
Net cash provided by (used in) financing activities		809,238	114,817	(215,578)
Net (decrease) increase in cash and cash equivalents		(119,054)	(225,060)	19,021
Cash and cash equivalents at beginning of year		381,202	606,262	587,241
Cash and cash equivalents at end of year		262,148	381,202	606,262
Supplemental Disclosures of Cash Flow Information:
Common stock issued for acquisitions, net of issuance costs		54,896	0	38,300
Parent Company
Operating Activities
Net income		92,349	82,064	69,306
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed (income) loss of subsidiaries		(25,968)	26,462	(26,280)
Depreciation of premises, furniture, and equipment		2	7	6
Net securities gains		0	(1)	(5,702)
Share-based compensation expense		7,879	7,242	5,926
Tax expense related to share-based compensation		(685)	(1,200)	(106)
Net (increase) decrease in other assets		(75,104)	23,699	4,599
Net increase (decrease) in other liabilities		74,571	(17,132)	14,063
Net cash provided by operating activities		73,044	121,141	61,812
Investing Activities
Purchases of securities available-for-sale		(14)	0	0
Proceeds from sales and maturities of securities available-for-sale		601	310	8,540
Purchase of premises, furniture, and equipment		0	5	0
Net cash paid for acquisitions		(14,905)	(16,047)	(15,809)
Net cash (used in) provided by investing activities		(14,318)	(15,742)	(7,269)
Financing Activities
Net proceeds from the issuance of subordinated debt		146,484	0	0
Payments for the retirement of senior and subordinated debt		(153,500)	0	0
Treasury stock activity		0	(120)	369
Cash dividends paid		(29,198)	(27,036)	(22,568)
Restricted stock activity		(2,476)	(2,890)	(2,781)
Excess tax benefit related to share-based compensation		488	794	912
Net cash provided by (used in) financing activities		(38,202)	(29,252)	(24,068)
Net (decrease) increase in cash and cash equivalents		20,524	76,147	30,475
Cash and cash equivalents at beginning of year		119,693	43,546	13,071
Cash and cash equivalents at end of year		140,217	119,693	43,546
Supplemental Disclosures of Cash Flow Information:
Common stock issued for acquisitions, net of issuance costs		$ 54,896	$ 0	$ 38,300
[1]	Comprised of restricted stock, restricted stock unit, and performance share awards expense.

Subsequent Events (Details) - N

Subsequent Events (Details) - Narrative - USD ($) $ / shares in Units, $ in Thousands	Jan. 06, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Acquisition and integration related expenses		$ 14,352	$ 1,389	$ 13,872
Standard Bancshares, Inc.
Subsequent Event [Line Items]
Acquisition and integration related expenses		$ 8,000
Standard Bancshares, Inc. | Subsequent Event
Subsequent Event [Line Items]
Fixed exchange ratio (in shares)	0.4350
Consideration transferred	$ 580,483
Common stock, shares issued (in shares)	21,057,085
Cash paid	$ 47,125
First Midwest Bancorp, Inc. | Subsequent Event
Subsequent Event [Line Items]
Share price (in dollars per share)	$ 25.34
Standard Bancshares, Inc. | Subsequent Event
Subsequent Event [Line Items]
Share price (in dollars per share)	$ 11.02
Forecast | Standard Bancshares, Inc.
Subsequent Event [Line Items]
Acquisition and integration related expenses	$ 27,000

Subsequent Events (Details) - A

Subsequent Events (Details) - Acquisition Activity - USD ($) $ / shares in Units, $ in Thousands	Jan. 06, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Goodwill		$ 340,879	$ 319,007	$ 310,589	$ 264,062
Standard Bancshares, Inc. | Subsequent Event
Assets
Cash and due from banks and interest-bearing deposits in other banks	$ 101,944
Securities available-for-sale	214,098
FHLB and FRB stock	3,247
Loans	1,795,562
OREO	9,223
Investment in BOLI	55,629
Goodwill	328,296
Other intangible assets	25,868
Premises, furniture, and equipment	56,253
Accrued interest receivable and other assets	48,707
Total assets	2,638,827
Liabilities
Noninterest-bearing deposits	676,295
Interest-bearing deposits	1,347,760
Total deposits	2,024,055
Accrued interest payable and other liabilities	34,289
Total liabilities	$ 2,058,344
Consideration Paid
Common stock, shares issued (in shares)	21,057,085
Shares issued (in dollars per share)	$ 25.34
Common stock (21,057,085 shares issued at $25.34 per share), net of issuance costs	$ 533,358
Cash paid	47,125
Total consideration paid	$ 580,483

Subsequent Events (Details) - U

Subsequent Events (Details) - Unaudited Pro Forma Combined Results of Operations (Details) - Standard Bancshares, Inc. $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Subsequent Event [Line Items]
Total revenues	$ 616,922	[1]
Net income	$ 108,770
[1]	Includes net interest income and total noninterest income.