MB Financial 10-K 1 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 28, 2019	Jun. 30, 2018
Document and Entity Information
Entity Registrant Name	MB FINANCIAL INC /MD
Entity Central Index Key	1,139,812
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-Known Seasoned User	Yes
Entity Voluntary Fliers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 3,844,832,201
Entity Common Stock; shares outstanding		84,479,464
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks	$ 503,153	$ 397,880
Interest earning deposits with banks	147,254	181,341
Total cash and cash equivalents	650,407	579,221
Investment securities:
Securities available for sale, at fair value	1,855,682
Securities available for sale, at fair value		1,408,326
Securities held to maturity, at amortized cost ($919,660 and $992,455 fair value at December 31, 2018 and 2017, respectively)	901,684	959,082
Marketable equity securities, at fair value	11,075	0
Non-marketable securities - FHLB and FRB stock	113,957	114,111
Total investment securities	2,882,398	2,481,519
Loans held for sale	45,550	548,578
Loans:
Total loans, excluding purchased credit impaired loans	13,951,082	13,846,318
Purchased credit impaired loans	84,101	119,744
Total loans	14,035,183	13,966,062
Less: Allowance for loan and lease losses	161,578	157,710
Net loans	13,873,605	13,808,352
Lease investment, net	487,776	409,051
Premises and equipment, net	270,614	286,690
Cash surrender value of life insurance	208,581	203,602
Goodwill	999,925	1,003,548
Other intangibles	46,914	54,766
Mortgage servicing rights, at fair value	284,898	276,279
Other real estate owned, net	9,182	9,736
Other real estate owned related to FDIC-assisted transactions	1,182	4,788
Other assets	445,994	420,810
Total assets	20,207,026	20,086,940
Deposits:
Non-interest bearing	6,152,163	6,381,512
Interest bearing	8,502,050	8,576,866
Total deposits	14,654,213	14,958,378
Short-term borrowings	1,470,055	861,039
Long-term borrowings	349,681	505,158
Junior subordinated notes issued to capital trusts	121,118	211,494
Accrued expenses and other liabilities	577,111	541,048
Total liabilities	17,172,178	17,077,117
STOCKHOLDERS’ EQUITY
Preferred stock	194,719	309,999
Common stock	862	858
Additional paid-in capital	1,708,319	1,691,007
Retained earnings	1,199,485	1,065,303
Accumulated other comprehensive (loss) income	(4,864)	3,584
Less: 1,944,358 and 1,883,810 shares of treasury stock, at cost, at December 31, 2018 and 2017, respectively	(63,673)	(60,928)
Total stockholders’ equity	3,034,848	3,009,823
Total liabilities and stockholders’ equity	$ 20,207,026	$ 20,086,940

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Nov. 22, 2017
Statement of Financial Position [Abstract]
Securities held to maturity, at amortized cost, fair value (in dollars)	$ 919,660	$ 992,455
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	120,000,000	120,000,000
Common stock, issued shares (in shares)	86,220,872	85,801,702
Treasury stock, shares (in shares)	1,944,358	1,883,810
Series A Preferred Stock
Preferred stock, dividend rate (percent)	8.00%	8.00%
Preferred stock, shares issued (in shares)	0	4,000,000
Preferred stock, shares outstanding (in shares)	0	4,000,000
Preferred stock, liquidation preference per share (in dollars per share)	$ 25	$ 25
Series B Preferred Stock
Preferred stock, dividend rate (percent)	8.00%	8.00%
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Preferred stock, liquidation preference per share (in dollars per share)	$ 1,000	$ 1,000
Series C Preferred Stock
Preferred stock, dividend rate (percent)	6.00%
Preferred stock, shares issued (in shares)	200,000
Preferred stock, shares outstanding (in shares)	200,000
Preferred stock, liquidation preference per share (in dollars per share)	$ 1,000		$ 1,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans:
Taxable	$ 659,993,000	$ 587,234,000	$ 467,877,000
Nontaxable	9,255,000	10,665,000	11,120,000
Investment securities:
Taxable	40,201,000	33,975,000	35,571,000
Nontaxable	37,776,000	39,218,000	42,022,000
Other interest earning accounts and Federal funds sold	2,381,000	1,354,000	587,000
Total interest income	749,606,000	672,446,000	557,177,000
Interest expense:
Deposits	75,270,000	40,685,000	25,579,000
Short-term borrowings	10,939,000	14,697,000	4,195,000
Long-term borrowings and junior subordinated notes	25,594,000	14,687,000	9,512,000
Total interest expense	111,803,000	70,069,000	39,286,000
Net interest income	637,803,000	602,377,000	517,891,000
Provision for credit losses	47,201,000	21,593,000	19,563,000
Net interest income after provision for credit losses	590,602,000	580,784,000	498,328,000
Non-interest income:
Mortgage banking revenue	63,515,000	109,224,000	151,716,000
Lease financing revenue, net	104,490,000	86,587,000	73,486,000
Treasury management fees	59,735,000	58,930,000	50,620,000
Wealth management fees	36,383,000	34,744,000	32,872,000
Card fees	21,654,000	18,596,000	16,071,000
Capital markets and international banking fees	12,333,000	15,708,000	13,332,000
Consumer and other deposit service fees	11,923,000	13,333,000	13,308,000
Brokerage fees	4,234,000	4,321,000	4,654,000
Loan service fees	8,748,000	8,317,000	7,457,000
Increase in cash surrender value of life insurance	4,979,000	5,421,000	4,075,000
Net (loss) gain on investment securities	(256,000)
Net (loss) gain on investment securities		562,000	447,000
Net loss on disposal of other assets	(796,000)	(2,323,000)	(794,000)
Other operating income	15,687,000	15,954,000	10,906,000
Total non-interest income	342,629,000	369,374,000	378,150,000
Non-interest expenses:
Salaries and employee benefits expense	427,560,000	419,179,000	400,501,000
Occupancy and equipment expense	65,445,000	62,556,000	57,130,000
Computer services and telecommunication expense	45,456,000	40,591,000	43,468,000
Advertising and marketing expense	13,420,000	12,235,000	11,971,000
Professional and legal expense	17,533,000	10,207,000	12,879,000
Other intangibles amortization expense	7,852,000	8,193,000	7,305,000
Branch exit and facilities impairment charges (recovery)	4,245,000	8,353,000	(2,709,000)
Net loss (gain) recognized on other real estate owned and other related expense	2,184,000	1,344,000	(1,599,000)
Loss on extinguishment of debt	11,898,000	0	0
Goodwill impairment loss	3,623,000	0	0
Other operating expenses	81,844,000	98,685,000	94,152,000
Total non-interest expenses	681,060,000	661,343,000	623,098,000
Income before income taxes	252,171,000	288,815,000	253,380,000
Income tax expense (benefit)	38,256,000	(15,225,000)	79,244,000
Net income	213,915,000	304,040,000	174,136,000
Dividends on preferred shares	12,100,000	8,007,000	8,009,000
Preferred Stock Redemption Discount	(15,280,000)	0	0
Net income available to common stockholders	$ 217,095,000	$ 296,033,000	$ 166,127,000
Common share data:
Basic earnings per common share (in dollars per share)	$ 2.58	$ 3.53	$ 2.16
Diluted earnings per common share (in dollars per share)	$ 2.55	$ 3.49	$ 2.13
Weighted average common shares outstanding for basic earnings per common share (in shares)	84,277,230	83,836,732	76,968,823
Diluted weighted average common shares outstanding for diluted earnings per common share (in shares)	85,206,300	84,823,456	77,976,121

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 213,915	$ 304,040	$ 174,136
Unrealized holding losses on investment securities, net of reclassification adjustments	(13,292)	(1,807)	(14,317)
Reclassification adjustment for amortization of unrealized gains on investment securities transferred to held to maturity from available for sale	606	(353)	(2,769)
Reclassification adjustments for losses (gains) included in net income	256	(562)	(447)
Other comprehensive loss, before tax	(12,430)	(2,722)	(17,533)
Income tax benefit related to items of other comprehensive loss	3,075	1,116	6,946
Other comprehensive loss, net of tax	(9,355)	(1,606)	(10,587)
Comprehensive income	$ 204,560	$ 302,434	$ 163,549

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net of Tax	Treasury Stock	Noncontrolling Interest
Beginning Balance at Dec. 31, 2015	$ 2,087,284	$ 115,280	$ 756	$ 1,280,870	$ 731,812	$ 15,777	$ (58,504)	$ 1,293
Increase (Decrease) in Stockholders' Equity
Net income	174,287				174,136			151
Other comprehensive loss, net of tax	(10,587)					(10,587)
Issuance of preferred and common stock due to business combination	385,099	1,227	97	383,775
Conversion of Series B preferred stock into common stock		(935)		935
Cash dividends declared on preferred shares	(8,009)				(8,009)
Cash dividends declared on common shares	(59,047)				(59,047)
Restricted common stock activity, net of tax	(75)		2	(2,171)			2,094
Stock option activity, net of tax	(320)		1	(164)			(157)
Repurchase of common shares in connection with employee benefit plans and held in trust for deferred compensation plan	(3,837)			(20)			(3,817)
Stock-based compensation expense	16,868			16,868
Additional investment in subsidiary	(2,336)			(1,267)				(1,069)
Distributions to noncontrolling interest	(118)							(118)
Ending Balance at Dec. 31, 2016	2,579,209	115,572	856	1,678,826	838,892	5,190	(60,384)	257
Increase (Decrease) in Stockholders' Equity
Net income	304,040				304,040
Other comprehensive loss, net of tax	(1,606)					(1,606)
Issuance of preferred stock, net of issuance costs	194,719	194,719
Conversion of Series B preferred stock into common stock	0	(292)		292
Cash dividends declared on preferred shares	(8,007)				(8,007)
Cash dividends declared on common shares	(69,622)				(69,622)
Restricted common stock activity, net of tax	(3,271)			(6,820)			3,549
Stock option activity, net of tax	1,041		2	1,039
Repurchase of common shares in connection with employee benefit plans and held in trust for deferred compensation plan	(3,329)			764			(4,093)
Stock-based compensation expense	17,476			17,476
Additional investment in subsidiary	(827)			(570)				(257)
Ending Balance at Dec. 31, 2017	3,009,823	309,999	858	1,691,007	1,065,303	3,584	(60,928)	0
Increase (Decrease) in Stockholders' Equity
Net income	213,915				213,915
Other comprehensive loss, net of tax	(9,355)					(9,355)
Stock Redeemed or Called During Period, Value	(100,000)	(115,280)			15,280
Cash dividends declared on preferred shares	(12,100)				(12,100)
Cash dividends declared on common shares	(81,709)				(81,709)
Restricted common stock activity, net of tax	(3,922)		2	(3,924)
Stock option activity, net of tax	1,451		2	1,449
Repurchase of common shares in connection with employee benefit plans and held in trust for deferred compensation plan	(1,685)			1,060			(2,745)
Stock-based compensation expense	18,727			18,727
Ending Balance at Dec. 31, 2018	$ 3,034,848	$ 194,719	$ 862	$ 1,708,319	$ 1,199,485	$ (4,864)	$ (63,673)	$ 0

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Cash dividends declared (in dollars per share)	$ 0.96	$ 0.82	$ 0.74

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows From Operating Activities
Net income	$ 213,915,000	$ 304,040,000	$ 174,136,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of premises and equipment and leased equipment	114,252,000	96,154,000	75,013,000
Facilities impairment charges	4,245,000	8,353,000	(2,709,000)
Compensation expense for share-based payment plans	18,727,000	17,476,000	16,868,000
Loss (gain) on sales of premises and equipment and leased equipment	721,000	(765,000)	783,000
Amortization of other intangibles	7,852,000	8,193,000	7,305,000
Provision for credit losses	47,201,000	21,593,000	19,563,000
Deferred income tax expense (benefit)	30,321,000	(33,493,000)	45,917,000
Amortization of premiums and discounts on investment securities, net	33,214,000	39,332,000	47,042,000
Accretion of premiums and discounts on loans, net	(16,585,000)	(27,840,000)	(29,211,000)
Debt Securities, Realized Gain (Loss)	256,000
Net loss (gain) on investment securities		(562,000)	(447,000)
Proceeds from sale of loans held for sale	2,511,756,000	5,010,415,000	6,687,670,000
Origination of loans held for sale	(2,110,088,000)	(4,829,690,000)	(6,630,361,000)
Net loss (gain) on sale of loans held for sale	11,137,000	15,834,000	(28,896,000)
Origination of mortgage servicing rights	(30,843,000)	(59,810,000)	(68,428,000)
Change in fair value and amortization/prepayments of mortgage servicing rights	22,385,000	22,407,000	3,666,000
Net loss (gain) on other real estate owned	1,274,000	920,000	(2,358,000)
Increase in cash surrender value of life insurance	(4,979,000)	(5,421,000)	(4,075,000)
Loss on extinguishment of debt	(11,898,000)	0	0
Goodwill impairment loss	3,623,000	0	0
Increase in other assets, net	(30,194,000)	(56,830,000)	(116,961,000)
Increase in other liabilities, net	2,111,000	43,654,000	57,112,000
Net cash provided by operating activities	842,199,000	573,960,000	251,629,000
Cash Flows From Investing Activities
Proceeds from sales of investment securities available for sale	2,610,000
Proceeds from sales of investment securities available for sale		8,804,000	28,024,000
Proceeds from maturities and calls of investment securities available for sale	387,702,000	357,210,000	336,357,000
Purchase of investment securities available for sale	(876,643,000)
Purchase of investment securities available for sale		(108,590,000)	(17,702,000)
Proceeds from maturities and calls of investment securities held to maturity	105,018,000	151,979,000	174,201,000
Purchase of investment securities held to maturity	(62,485,000)	(54,206,000)	(31,410,000)
Purchase of marketable equity securities	(442,000)	0	0
Proceeds from sales of marketable equity securities	178,000	0	0
Purchase of non-marketable securities - FHLB and FRB stock	(76,020,000)	(135,498,000)	(60,316,000)
Redemption of non-marketable securities - FHLB and FRB stock	76,174,000	164,663,000	47,273,000
Net increase in loans	(16,851,000)	(1,151,104,000)	(1,023,221,000)
Purchases in mortgage servicing rights	(161,000)	(865,000)	(5,087,000)
Purchases of premises and equipment and leased equipment	(179,052,000)	(188,762,000)	(191,922,000)
Proceeds from sales of premises and equipment and leased equipment	6,701,000	25,431,000	6,819,000
Capital improvements on other real estate owned	0	0	(96,000)
Proceeds from sale of other real estate owned	5,002,000	22,422,000	15,917,000
Proceeds from sale of other real estate owned related to FDIC-assisted transactions	3,515,000	3,216,000	8,968,000
Life insurance death benefit	0	2,764,000
Net cash paid in business acquisition	0	(3,780,000)	(9,010,000)
Purchase of additional investment in subsidiary from minority owners	0	(827,000)	(2,336,000)
Net payments for FDIC related covered assets	1,068,000	(713,000)	(4,113,000)
Net cash used in investing activities	(623,686,000)	(907,856,000)	(727,654,000)
Cash Flows From Financing Activities
Net (decrease) increase in deposits	(304,165,000)	847,930,000	215,906,000
Proceeds from short-term borrowings - FHLB advances	765,000,000	3,125,000,000	3,175,000,000
Principal paid on short-term borrowings - FHLB advances	(1,000,000,000)	(4,000,000,000)	(2,975,000,000)
Net increase (decrease) in short-term borrowings - other	484,016,000	(58,249,000)	15,246,000
Proceeds from long-term borrowings	477,065,000	532,497,000	267,359,000
Principal paid on long-term borrowings	(272,542,000)	(114,129,000)	(71,845,000)
Redemption of junior subordinated notes issued to capital trusts	103,096,000	0	0
Issuance of preferred stock, net of issuance costs	0	194,719,000	0
Redemption of preferred stock	100,000,000	0	0
Treasury stock transactions, net	(1,685,000)	(3,271,000)	(3,837,000)
Stock options exercised	4,063,000	2,504,000	1,410,000
Dividends paid on preferred stock	(14,100,000)	(8,007,000)	(8,009,000)
Dividends paid on common stock	(81,883,000)	(69,346,000)	(58,177,000)
Net cash (used in) provided by financing activities	(147,327,000)	449,648,000	558,053,000
Net increase in cash and cash equivalents	71,186,000	115,752,000	82,028,000
Cash and cash equivalents:
Beginning of year	579,221,000	463,469,000	381,441,000
End of year	650,407,000	579,221,000	463,469,000
Cash payments for:
Interest paid to depositors and other borrowed funds	111,045,000	67,899,000	38,538,000
Income tax payments (refunds), net	787,000	(3,505,000)	14,188,000
Supplemental Schedule of Noncash Investing Activities:
Investment securities held to maturity purchased not settled	0	0	(761,000)
Transfer of investment securities held to maturity to investment securities available for sale	2,610,000	0	0
Loans held for sale transferred to loans held for investment	83,400,000	29,508,000	0
Loans transferred to other real estate owned	5,260,000	6,686,000	4,945,000
Loans transferred to other real estate owned related to FDIC-assisted transactions	211,000	2,771,000	2,885,000
Loans transferred to repossessed vehicles	2,740,000	2,013,000	3,072,000
Operating leases rewritten as direct finance leases included as loans	3,829,000	1,680,000	910,000
Long-term borrowings transferred to short-term borrowings	360,000,000	225,000,000	300,000,000
Noncash assets acquired:
Investment securities available for sale	0		505,564,000
Non-marketable securities -FHLB and FRB stock	0	0	16,000,000
Loans	0	1,846,000	1,940,702,000
Premises and equipment		157,000	39,048,000
Cash surrender value of life insurance	0	0	59,917,000
Goodwill		2,510,000	275,968,000
Other intangibles			25,452,000
Other real estate owned	0	0	3,960,000
Other assets		(733,000)	32,141,000
Total noncash assets acquired	0	3,780,000	2,898,752,000
Liabilities assumed:
Deposits	0	0	2,389,327,000
Short-term borrowings	0	0	48,305,000
Long-term borrowings	0	0	16,000,000
Junior subordinated notes issued to capital trusts	0	0	28,075,000
Other liabilities			22,966,000
Total liabilities assumed	$ 0	$ 0	$ 2,504,673,000

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies MB Financial, Inc. (the "Company," "we," "us," "our") is a financial holding company that provides a full range of financial services to individuals and corporate customers through its banking subsidiary, MB Financial Bank, N.A. ("MB Financial Bank"). The Company’s primary market is the Chicago, Illinois metropolitan area, in which MB Financial Bank operates 86 banking offices through MB Financial Bank. MB Financial Bank, our largest subsidiary, has two wholly owned subsidiaries with significant operating activities: MB Equipment Finance, LLC and MSA Holdings, LLC. Basis of Financial Statement Presentation: The consolidated financial statements include the accounts of the Company and its subsidiaries. Significant intercompany items and transactions have been eliminated in consolidation. The accounting and reporting policies of the Company conform to accounting principles generally accepted in the United States of America and general practices within the financial services industry. In accordance with applicable accounting standards, the Company does not consolidate statutory trusts established for the sole purpose of issuing trust preferred securities and related trust common securities. See Note 12 below for more detail. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and revenues and expenses for the year. Actual results could differ from those estimates. Areas involving the use of management’s estimates and assumptions, which are more susceptible to change in the near term include the allowance for loan and lease losses; residual value of direct finance, leveraged, and operating leases; valuation of mortgage servicing rights; income tax accounting; fair value measurements for assets and liabilities; and goodwill. Cash and cash equivalents: For purposes of reporting cash flows, cash and cash equivalents includes cash on hand, amounts due from banks (including cash items in process of clearing), interest bearing deposits with banks, with original maturities of 90 days or less. Investment securities: Securities classified as available for sale are those securities that the Company intends to hold for an indefinite period of time, but not necessarily to maturity. Any decision to sell a security classified as available for sale is based on various factors, including movements in interest rates, changes in the maturity mix of assets and liabilities, liquidity needs, regulatory capital considerations, and other factors. Securities available for sale are reported at fair value with unrealized gains or losses reported as accumulated other comprehensive income, net of the related deferred tax effect. Securities classified as held to maturity are those securities that the Company intends to hold until maturity and are reported at amortized cost. 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 level-yield method. In determining the estimated life of a mortgage-related security, certain judgments are required as to the timing and amount of future principal prepayments. These judgments are made based upon the actual performance of the underlying security and the general market consensus regarding changes in mortgage interest rates and underlying prepayment estimates. Amortization of premium and accretion of discount is included in interest income from the related security. Realized gains or losses, determined on the basis of the cost of specific securities sold, are included in earnings. The Company evaluates the portfolio for impairment each quarter. In estimating other-than-temporary losses, the Company considers the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, and whether the Company is more likely than not to sell the security before recovery of its cost basis. If the Company intends to sell an impaired security, the Company records an other-than-temporary loss in an amount equal to the entire difference between the fair value and amortized cost. If a security is determined to be other-than-temporarily impaired, but the Company does not intend to sell the security, only the credit portion of the estimated loss is recognized in earnings, with the other portion of the loss recognized in other comprehensive income. Federal Home Loan Bank and Federal Reserve Bank stock: The Company owns investments in the stock of the Federal Reserve Bank of Chicago (“FRB”) and the Federal Home Loan Bank of Chicago (“FHLB”). No ready market exists for these stocks, and they have no quoted market values. The Bank, as a member of the Federal Reserve System and the FHLB, is required to maintain an investment in the capital stock of the FRB and FHLB. The stock is redeemable at par by the FRB and FHLB, respectively, and is, therefore, carried at cost and periodically evaluated for impairment. Loans held for sale: Mortgage loans originated and intended for sale in the secondary market are reflected at fair value as elected. Changes in the fair value are recognized in mortgage banking revenue on the Company's Consolidated Statements of Operations. Mortgage Loan Representation and Warranty Reserve: The Company originates and sells residential mortgage loans in the secondary market. When the Company sells mortgage loans, it makes customary representations and warranties to the purchasers about various characteristics of each loan, such as the ownership of the loan, the validity of the lien securing the loan, the nature and extent of underwriting standards applied and the types of documentation being provided. These representations and warranties are generally enforceable over the life of the loan. If a defect in the origination process is identified, the Company may be required to either repurchase the loan or indemnify the purchaser for losses it sustains on the loan. If there are no such defects, the Company has no liability to the purchaser for losses it may incur on such loans. Representation and warranty reserves were $5.3 million and $7.0 million as of December 31, 2018 and 2017, respectively. The Company maintains a representation and warranty reserve to account for the expected losses related to loans it might be required to repurchase or the indemnity payments it may have to make to purchasers. The representation and warranty reserve reflects management's best estimate of probable lifetime loss. The reserve considers both the estimate of expected losses on loans sold during the current accounting period as well as adjustments to the Company's previous estimate of expected losses on loans sold. Factors considered include borrower performance, repurchase demand behavior, and historical loan defect experience. Management monitors the adequacy of the overall reserve and makes adjustments to the level of reserve, as necessary, after consideration of other qualitative factors. At the time a loan originated for sale is funded, the representation and warranty reserve is recorded as a decrease in mortgage banking revenue on the Consolidated Statements of Operations and recorded in accrued interest, taxes and other liabilities on the Company's Consolidated Balance Sheets. Changes to the reserve are recorded as an increase or decrease to mortgage banking revenue on the Consolidated Statements of Operations. Loans and leases: Loans are stated at the amount of unpaid principal reduced by the allowance for loan and lease losses and unearned income. Direct finance and leveraged leases are included as lease loans for financial statement purposes. Direct finance leases are stated as the sum of remaining minimum lease payments from lessees plus estimated residual values less unearned lease income. Leveraged leases are stated as the sum of remaining minimum lease payments from lessees (less nonrecourse debt payments) plus estimated residual values less unearned lease income. On an annual basis, management reviews the lease residuals for potential impairment. Unearned lease income on direct finance and leveraged leases is recognized over the lives of the leases using the level-yield method. Loan origination and commitment fees and certain direct loan origination costs are deferred and the net amount amortized as an adjustment of the related loan’s yield. The Company is amortizing these amounts over the contractual life of the loan. Commitment fees based upon a percentage of a customer’s unused line of credit and fees related to standby letters of credit are recognized over the commitment period. Interest income is accrued daily on the Company’s outstanding loan balances. The accrual of interest on loans is discontinued at the time the loan is 90 days past due unless the credit is well-secured and in process of renewal or collection. Past due status is based on contractual terms of the loan. In all cases, loans are placed on non-accrual or charged-off at an earlier date if collection of principal or interest is considered doubtful. All interest accrued but not collected for loans that are placed on non-accrual or charged-off is reversed against interest income. For impaired loans, accrual of interest is discontinued on a loan when management believes, after considering collection efforts and other factors, the borrower’s financial condition is such that collection of interest is doubtful. Cash collections on impaired loans are generally credited to the loan balance, and no interest income is recognized on those loans until the principal balance has been determined to be collectible. Loans, other than those included in large groups of smaller-balance homogeneous loans, are considered impaired when it is probable the Company will be unable to collect all contractual principal and interest payments due in accordance with the terms of the loan agreement. Impaired loans include non-accrual loans and loans classified as troubled debt restructurings. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or, as a practical expedient, based on the loan’s observable market price or the fair value of the collateral if the loan is collateral dependent. The amount of impairment, if any and any subsequent changes are charged against the allowance for loan and lease losses. Troubled debt restructurings: A loan is classified as a troubled debt restructuring when a borrower is experiencing financial difficulties that leads to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include rate reductions, principal forgiveness, deferral of past due interest or principal, extension of maturity date, modification of amortization schedules, redemption of past due taxes and other actions intended to minimize potential losses. In determining whether a debtor is experiencing financial difficulties, the Company considers if the debtor is in payment default or would be in payment default in the foreseeable future without the modification, the debtor declared or is in the process of declaring bankruptcy, there is substantial doubt that the debtor will continue as a going concern, the debtor has securities that have been or are in the process of being delisted, the debtor’s entity-specific projected cash flows will not be sufficient to service any of its debt, or the debtor cannot obtain funds from sources other than the existing creditors at a market rate for debt with similar risk characteristics. In determining whether the Company has granted a concession, the Company assesses, if it does not expect to collect all amounts due, whether the current value of the collateral will satisfy the amounts owed, whether additional collateral or guarantees from the debtor will serve as adequate compensation for other terms of the restructuring, and whether the debtor otherwise has access to funds at a market rate for debt with similar risk characteristics. A loan that is modified at a market rate of interest will not be classified as troubled debt restructuring in the calendar year subsequent to the restructuring if it is in compliance with the modified terms. Payment performance prior and subsequent to the restructuring is taken into account in assessing whether it is likely that the borrower can meet the new terms. Under certain circumstances, a loan may be returned to accrual at the time of restructuring. A period of sustained repayment for at least six months generally is required for return to accrual status. Consistent with regulatory guidance, a troubled debt restructuring loan that is subsequently modified in another restructuring agreement but has shown sustained performance will be removed from troubled debt restructuring status provided the modified terms were market based at the time of modification. Allowance for loan and lease losses: The allowance for loan and lease losses ("ALLL") is established through a provision for credit losses charged to expense. Loans are charged against the ALLL when management believes that collectability of the principal is unlikely. The allowance is an amount that management believes will be appropriate to absorb probable losses on existing loans, based on an evaluation of the collectability of loans and prior loss and recovery experience as appropriate under GAAP. The ALLL is based on management’s evaluation of the loan portfolio giving consideration to the nature and volume of the loan portfolio, the value of underlying collateral, overall portfolio quality, review of specific problem loans, prevailing economic conditions that may affect the borrower’s ability to pay, as well as other qualitative and environmental factors. While management uses the best information available to make its evaluation, future adjustments to the allowance may be necessary if there are significant changes in economic conditions. In addition, regulatory agencies, as an integral part of their examination process, periodically review MB Financial Bank’s ALLL, and may require it to recognize adjustments to its allowance based on their judgments of information available to them at the time of their examinations. The ALLL is comprised of three elements: a commercial related general loss reserve; a commercial related specific reserve for impaired loans; and a consumer related reserve for smaller-balance homogenous loans. Each element is discussed below. Commercial Related General Loss Reserve - We maintain a general loan loss reserve for the four categories of commercial related loans in our portfolio - commercial loans, commercial loans collateralized by the assignment of lease payments (lease loans), commercial real estate loans and construction real estate loans. Under our loan risk rating system, each loan, with the exception of those included in large groups of smaller-balance homogeneous consumer related loans, is risk rated between one and nine by the originating loan officer, Senior Credit Management, Loan Review or loan committee. A loan rated "one" represents a loan least likely to default, while a loan rated " nine " represents a loss. The probability of loans defaulting for each risk rating, sometimes referred to as default factors, are estimated based on the frequency with which loans migrate from one risk rating to another and to default status over time. We use a loan loss reserve model that incorporates loan risk rating migrations and historical default data over a multi-year period to develop estimated default factors ("EDFs"). The model tracks annual loan rating migrations by loan type over the last 18 years and is adjusted to reflect average losses over an economic cycle. EDFs are updated annually in December. EDFs are multiplied by individual loan balances in each risk-rating category and by an historical loss given default estimate for each loan type (which incorporates recoveries) to determine the appropriate allowance by loan type. This approach is applied to the commercial, lease, commercial real estate, and construction real estate components of the portfolio. To account for current economic conditions, the general allowance for loan and lease losses also includes macroeconomic factor adjustments. Macroeconomic factors adjust the ALLL upward or downward based on the current point in the economic cycle using predictive economic data and are applied to the loan loss model through a separate allowance element for the commercial, commercial real estate, construction real estate and lease loan components. To determine our macroeconomic factors, we use specific economic data that are deemed predictive of future credit losses. We tested over 20 economic variables (U.S. manufacturing index, unemployment rate, U.S. GDP growth, etc.). We review this data annually to determine that such relationships continue to exist. We currently use the following macroeconomic indicators in our macroeconomic factor computation: • Commercial loans and lease loans: BBB-rated debt yield and number of civilians unemployed for 27 weeks or more. • Commercial real estate loans and construction loans: Non-performing loans to total loans, Capacity Utilization: Total Industry (percent of capacity), and the Chicago Fed's National Financial Conditions Index. Using the indicators noted above, a net charge-off rate is estimated and compared to our cycle average rate, resulting in a macroeconomic adjustment factor. The macroeconomic adjustment factor is applied to each commercial loan type. Each year, we evaluate the predictive nature of the macroeconomic factors and re-calibrate the macroeconomic models as needed. Commercial Related Specific Reserves - The ALLL also includes specific reserves on impaired commercial related loans. A loan is considered to be impaired when management believes, after considering collection efforts and other factors, the borrower’s financial condition is such that the collection of all contractual principal and interest payments due is doubtful. At each quarter-end, impaired loans are reviewed individually, with adjustments made to the general calculated reserve for each loan as deemed necessary. Specific adjustments are made depending on expected cash flows and/or the value of the collateral securing each loan. Generally, the Company obtains a current external appraisal (within 12 months) on real estate secured impaired loans. Our appraisal policy is designed to comply with the Interagency Appraisal and Evaluation Guidelines. As part of our compliance with these guidelines, we maintain an internal Appraisal Review Department that engages and reviews all third party appraisals. In addition, each impaired commercial loan with real estate collateral is reviewed quarterly by our appraisal department to determine that the most recent valuation remains appropriate during subsequent quarters until the next appraisal is received. If considered necessary by our appraisal department, the appraised value may be further discounted to reflect current values. Other valuation techniques are also used to value non-real estate assets. Discounts may be applied in the impairment analysis used for general business assets ("GBA"). Examples of GBA include accounts receivable, inventory, and any marketable securities pledged. The discount is used to reflect collection risk in the event of default that may not have been included in the valuation of the asset. Consumer Related Reserves - Pools of homogeneous loans with similar risk and loss characteristics are also assessed for probable losses. These loan pools include consumer, residential real estate, home equity, credit cards and indirect vehicle loans. Migration probabilities obtained from past due roll rate analyses and historical loss rates are applied to current balances to forecast charge-offs over a one -year time horizon. We consistently apply our methodology for determining the appropriateness of the allowance for loan and lease losses but may adjust our methodologies and assumptions based on historical information related to charge-offs and management's evaluation of the loan portfolio. In this regard, we periodically review the following to validate our allowance for loan and lease losses: historical net charge-offs as they relate to prior periods' allowance for loan and lease loss, comparison of historical loan migration in past years compared to the current year, overall credit trends and ratios, any significant changes in loan concentrations, lending policies, and emerging impacts in the legal/regulatory landscape. In reviewing this data, we adjust qualitative factors within our allowance methodology to appropriately reflect any changes warranted by the validation process. Acquired loans: Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date without a carryover of the related allowance for loan and lease losses. These acquired loans are segregated into three types: pass rated loans with no discount attributable to credit quality, non-impaired loans with a discount attributable at least in part to credit quality and impaired loans with evidence of significant credit deterioration. • Pass rated loans (typically performing loans) are accounted for in accordance with ASC Topic 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination. • Non-impaired loans (typically performing substandard loans) are accounted for in accordance with ASC Topic 310-30 if they display at least some level of credit deterioration since origination. • Impaired loans (typically substandard loans on non-accrual status) are accounted for in accordance with ASC Topic 310-30 as they display significant credit deterioration since origination. For pass rated loans (non-purchased credit-impaired loans), the difference between the estimated fair value of the loans and the principal outstanding is accreted over the remaining life of the loans. The Company anticipates recording a provision for the acquired portfolio in future quarters related to renewing acquired loans which will offset a substantial portion of the accretion from the pass rated loans. In accordance with ASC Topic 310-30, for both purchased non-impaired loans (performing substandard loans) and purchased credit-impaired loans, the loans are pooled by loan type and the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan pools when there is a reasonable expectation about the amount and timing of such cash flows. Substantially all of the loans acquired in transactions with the FDIC displayed at least some level of credit deterioration and as such are included as non-impaired and impaired loans as described immediately above. Lease investments: The Company’s investment in operating leases is reported as lease investments, net. Rental income on operating leases is recognized as income over the lease term according to the provisions of the lease, which is generally on a straight-line basis. The investment in equipment in operating leases is stated at cost less depreciation using the straight-line method generally over a life of five years or less. Premises and equipment: Premises and equipment are carried at cost less accumulated depreciation and amortization. Depreciation and amortization is computed by the straight-line method over the estimated useful lives of the assets. Useful lives generally range from three to seven years for computer equipment and software, five to 10 years for furniture and equipment, and five to 39 years for buildings and building improvements. Land improvements are amortized over a period of 15 years and leasehold improvements are amortized over the term of the related lease or the estimated useful lives of the improvements, whichever is shorter. Land is not subject to depreciation. Maintenance and repairs are charged to expense as incurred, while major improvements are capitalized and amortized to operating expense over their identified useful lives. Premises and equipment and other long-lived assets are tested for impairment whenever events or changes in circumstances indicate the carrying amount of the assets may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value. Assets acquired through a business acquisition are recorded at fair value as of the acquisition date. Other real estate owned: Other real estate owned includes real estate assets that have been received in satisfaction of debt. Other real estate owned is initially recorded at fair value less estimated selling costs, which establishes the cost basis. Subsequently, other real estate owned is carried at the lower of the cost basis or fair value less estimated selling costs. Any valuation adjustments required at the date of transfer are charged to the allowance for loan and lease losses. Subsequently, unrealized losses and realized gains and losses on sale are included in net (gain) loss recognized on other real estate owned. Cash surrender value of life insurance: The Company has purchased bank-owned life insurance policies on certain executives. Bank-owned life insurance is recorded at its cash surrender value. Changes in the cash surrender values are included in non-interest income. Goodwill : The excess of the cost of an acquisition over the fair value of the net assets acquired, including core deposit and client relationship intangibles, consists of goodwill. Under the provisions of ASC Topic 350, goodwill is subject to at least annual assessments for impairment by applying a fair value based test. The Company reviews goodwill and other intangible assets to determine potential impairment annually, or more frequently if events and circumstances indicate that the asset might be impaired, by comparing the carrying value of the asset with the anticipated future cash flows. The Company's annual assessment is done as of December 31 at the reporting unit level. The Company currently has three reporting units: Banking, Leasing and Mortgage Banking. On April 12, 2018, the Company announced the discontinuation of its national mortgage origination business, which includes substantially all originations outside of the Company's consumer banking footprint in the Chicagoland area. As a result, the Company recorded an impairment loss in the amount of $3.6 million within the Mortgage Banking segment in the year ended December 31, 2018. Other intangibles : The Company’s other intangible assets consist of core deposit and customer intangibles obtained through acquisitions. Core deposit intangibles (the portion of an acquisition purchase price which represents value assigned to the existing deposit base) have finite lives and are amortized by a 150% declining balance method over four to 20 years. Other intangible assets are tested for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value. Mortgage Servicing Rights : The Company originates and sells residential mortgage loans in the secondary market and may retain the right to service the loans sold. Servicing involves the collection of payments from individual borrowers and the distribution of those payments to the investors. Upon a sale of mortgage loans for which servicing rights are retained, the retained mortgage servicing rights asset is capitalized at the fair value of future net cash flows expected to be realized for performing servicing activities. Purchased mortgage servicing rights are recorded at the purchase price at the date of purchase and at fair value thereafter. Mortgage servicing rights do not trade in an active market with readily observable prices. The Company determines the fair value of mortgage servicing rights by estimating the fair value of the future cash flows associated with the mortgage loans being serviced. Key economic assumptions used in measuring the fair value of mortgage servicing rights include, but are not limited to, prepayment speeds, discount rates, delinquencies and cost to service. The assumptions used in the valuation model are validated on a periodic basis. The fair value is validated on a quarterly basis with an independent third party. The Company has elected to account for mortgage servicing rights using the fair value option. Changes in the fair value are recognized in mortgage banking revenue on the Company's Consolidated Statements of Operations. FDIC indemnification asset : As part of the Heritage Community Bank ("Heritage"), Benchmark Bank ("Benchmark"), Broadway Bank ("Broadway"), and New Century Bank ("New Century") FDIC-assisted transactions, MB Financial Bank entered into loss-share agreements with the FDIC. These agreements cover realized losses on loans and foreclosed real estate for specified periods. See Note 5 below for more information on these agreements, including the duration of MB Financial Bank’s loss-share coverage. These loss-share assets are measured separately from the loan portfolios because they are not contractually embedded in the loans and are not transferable with the loans should MB Financial Bank choose to dispose of them. Fair values at the acquisition dates were estimated based on projected cash flows available for loss-share based on the credit adjustments estimated for each loan pool and the loss-share percentages. The loss-share assets are also separately measured from the related loans and foreclosed real estate and recorded within other assets on the balance sheet. The corresponding accretion is recorded in other income on the statement of operations. Although these assets are contractual receivables from the FDIC, there are no contractual interest rates. Subsequent to December 31, 2018, the Company exited the loss-share agreements with the FDIC. See Note 25. Subsequent Event for further details. Preferred stock: Preferred stock issued in connection with the Taylor Capital Group, Inc. and American Chartered Bancorp, Inc. mergers was initially recorded at fair value. Preferred stock issued through an underwritten public offering was recorded at the liquidation preference less underwriting discounts and other allowable costs. Preferred dividends declared are deducted from net income for computing net income available to common stockholders and earnings per common share computations. Treasury stock: Treasury stock is recorded at acquisition cost. Gains and losses on disposition are recorded as increases or decreases to additional paid-in capital with losses in excess of previously recorded gains charged directly to retained earnings. Derivative financial instruments and hedging activities : ASC Topic 815 establishes accounting and reporting standards requiring that every derivative instrument (including certain derivative instruments embedded in other contracts) be recorded in the balance sheet as either an asset or liability measured at its fair value. ASC Topic 815 requires that changes in the derivative’s fair value be recognized currently in earnings unless specific hedge accounting criteria are met. Accounting for qualifying hedges allows a derivative’s gains and losses to offset related results on the hedged item in the statement of operations, and requires that a company formally document, designate and assess the effectiveness of transactions that receive hedge accounting. All derivatives are recognized on the consolidated balance sheet at their fair value. On the date the derivative contract is entered into, the Company designates the derivative as either a fair value hedge (i.e. a hedge of the fair value of a recognized asset or liability), a cash flow hedge (i.e. a hedge of the variability of cash flows to be received or paid related to a recognized asset or liability), or a non-designated derivative (i.e. an instrument with no hedging designation). For a derivative designated as a fair value hedge, the changes in the fair value of the derivative and of the hedged item attributable to the hedged risk are recognized

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Business Combinations	Business Combinations American Chartered Bancorp, Inc. On August 24, 2016, American Chartered Bancorp, Inc. ("American Chartered"), an Illinois corporation, was merged (the "American Chartered Merger") with and into the Company, pursuant to the Agreement and Plan of Merger, dated as of November 20, 2015 (the "Merger Agreement"), by and between the Company and American Chartered. This transaction continues to solidify the Company's market position in Chicago. At the effective time of the merger (the "American Chartered Effective Time"), (i) each share of the common stock, no par value, of American Chartered ("American Chartered Common Stock") that was issued and outstanding immediately prior to the American Chartered Effective Time, (ii) each share of American Chartered’s 8% Cumulative Voting Convertible Preferred Stock, Series D ("American Chartered Series D Preferred Stock"), that was issued and outstanding immediately prior to the American Chartered Effective Time whose holder elected pursuant to American Chartered’s charter to receive the same consideration in the American Chartered Merger as holders of American Chartered Common Stock, based on the number of shares of American Chartered Common Stock into which such share of American Chartered Series D Preferred Stock would otherwise then be convertible, and (iii) each share of American Chartered Non-Voting Perpetual Preferred Stock, Series F, that was issued and outstanding immediately prior to the American Chartered Effective Time, was converted into the right to receive, subject to the election and proration procedures set forth in the Merger Agreement: (1) cash in the amount of $9.30 (the "Cash Consideration") or (2) 0.2732 shares of the Company's common stock, with cash paid in lieu of fractional Company shares determined by multiplying the fractional Company share amount by $39.01 (the average closing sale price of the Company's common stock for the five full trading days ending on August 23, 2016) (the "Stock Consideration"). The holders of such shares of American Chartered stock also could elect to receive a combination of the Cash Consideration and the Stock Consideration for their shares. Each share of American Chartered Series D Preferred Stock whose holder did not elect to receive the same consideration in the American Chartered Merger as holders of American Chartered Common Stock, based on the number of shares of American Chartered Common Stock into which such share of American Chartered Series D Preferred Stock would otherwise then be convertible, was converted into the right to receive one share of the Company's 8% cumulative voting convertible preferred stock, Series B. Consideration paid was $487.4 million , including $382.8 million in common stock ( 9.7 million shares), $102.3 million in cash and $2.3 million in preferred stock and stock-based awards assumed. The $102.3 million in cash consideration includes payments for the value of the net option shares of the American Chartered stock options pursuant to the Merger Agreement. This business combination was accounted for under the acquisition method of accounting. Accordingly, the results of operations of the acquired company have been included in the Company’s results of operations since the date of acquisition. Under this method of accounting, the assets acquired, liabilities assumed and consideration paid are recorded at their estimated fair values. The excess cost over fair value of net assets acquired is recorded as goodwill. As the consideration paid for American Chartered exceeded the net assets acquired, goodwill of $274.9 million was recorded on the acquisition and allocated to the banking segment. Goodwill recorded in the transaction, which reflects the increased Chicago market share and related synergies expected from the combined operations, is not tax deductible. The amounts recognized for the business combination in the financial statements have been determined to be final as of March 31, 2017. Estimated fair values of the assets acquired and liabilities assumed in the American Chartered Merger, as of the closing date of the transaction were as follows (in thousands): August 24, 2016 ASSETS Cash and cash equivalents $ 93,307 Investment securities available for sale 505,564 Non-marketable securities - FRB and FHLB Stock 16,000 Loans 1,942,548 Premises and equipment 39,048 Cash surrender value of life insurance 59,917 Goodwill 274,885 Other intangibles 25,452 Other real estate owned 3,960 Other assets 31,408 Total assets $ 2,992,089 LIABILITIES Deposits $ 2,389,327 Short-term borrowings 48,305 Long-term borrowings 16,000 Junior subordinated notes issued to capital trusts 28,075 Accrued expenses and other liabilities 22,966 Total liabilities $ 2,504,673 Total identifiable net assets $ 487,416 Consideration: Market value of common stock at $39.28 per share at August 24, 2016 (9,744,636 shares of common stock issued) $ 382,769 Series B preferred stock at $2,337.97 per share at August 24, 2016 (525 shares of preferred stock issued) (1) 1,227 Stock-based compensation attributed to pre-business combination service 1,103 Cash paid 102,317 Total fair value of consideration, excluding Series B preferred stock $ 487,416 (1) Per share fair value amount determined as if the shares of Series B were converted into shares common stock. Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date without a carryover of the related allowance for loan and lease losses. These acquired loans are segregated into three types: pass rated loans with no discount attributable to credit quality, non-impaired loans with a discount attributable at least in part to credit quality and impaired loans with evidence of significant credit deterioration. • Pass rated loans (typically performing loans) are accounted for in accordance with ASC Topic 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination. • Non-impaired loans (typically performing substandard loans) are accounted for in accordance with ASC Topic 310-30 if they display at least some level of credit deterioration since origination. • Impaired loans (typically substandard loans on non-accrual status) are accounted for in accordance with ASC Topic 310-30 as they display significant credit deterioration since origination. For pass rated loans (non-purchased credit-impaired loans), the difference between the estimated fair value of the loans and the principal outstanding is accreted over the remaining life of the loans. In accordance with ASC Topic 310-30, for both purchased non-impaired loans (performing substandard loans) and purchased credit-impaired loans, the loans are pooled by loan type and the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan pools when there is a reasonable expectation about the amount and timing of such cash flows. The following table presents the acquired loans as of the acquisition date (in thousands): Purchased Purchased Non-Credit-Impaired Fair value $ 62,104 $ 1,880,444 Gross contractual amounts receivable 93,490 2,149,868 Best estimate of contractual cash flows not expected to be collected (1) 22,293 114,154 Best estimate of contractual cash flows expected to be collected 71,197 2,035,714 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default. During 2017, the fair value estimates of loans increased by $1.8 million compared to previously reported balances at December 31, 2016, which decreased the deferred tax asset by $733 thousand and goodwill by $1.1 million as of December 31, 2017. The accretable discount for the non-purchased credit-impaired loans was $20.7 million as of the date of the acquisition. The non-accretable and accretable discount for the purchased credit-impaired loans was $18.4 million and $5.3 million , respectively, as of the date of the acquisition. The Company incurred costs of $2.0 million directly related to the consummation of the American Chartered Merger for the year ended December 31, 2016, which is recorded in professional and legal fees on the statement of operations. The data processing systems were converted in September 2016. The following table provides the unaudited pro forma information for the results of operations for the year ended December 31, 2016, as if the acquisition had occurred January 1, 2015. The pro forma results combine the historical results of American Chartered into the Company's consolidated statement of operations including the impact of certain acquisition accounting adjustments including loan discount accretion, investment securities discount accretion, intangible assets amortization, deposit premium accretion and borrowing discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2015. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The merger related expenses that have been recognized are included in net income in the table below. Year Ended December 31, 2016 (in thousands) Total revenues (net interest income plus non-interest income) $ 975,188 Net income 197,046 Revenues and earnings of the acquired company since the acquisition date have not been disclosed as it is not practicable as American Chartered was merged into the Company and separate financial information is not readily available. Definitive Merger Agreement On May 20, 2018, the Company entered into an Agreement and Plan of Merger (the "Merger Agreement") with Fifth Third Bancorp, an Ohio corporation ("Fifth Third"), pursuant to which a newly formed subsidiary of Fifth Third will be merged with and into the Company, with the Company as the surviving corporation (the “Merger”). At the effective time of the Merger (the "Effective Time"), each outstanding share of Company Common Stock will be converted into the right to receive (i) 1.45 shares of Fifth Third common stock ("Fifth Third Common Stock"), and (ii) $5.54 in cash (collectively, the "Merger Consideration"). The Company’s Series C Preferred Stock will remain outstanding and unchanged (except as modified by the Charter Amendment, as defined below) as preferred stock of the Company, which will be a subsidiary of Fifth Third. Pursuant to an amendment to the Company's charter (the "Charter Amendment") that will become effective immediately prior to consummation of the Merger, the holders of Company Series C Preferred Stock will have the right to vote with the holders of Company Common Stock as a single class on all matters submitted to a vote of such common stockholders. Upon completion of the Merger, Fifth Third, as the sole holder of Company Common Stock, will control the Company. Following completion of the Merger, the holders of Company Series C Preferred Stock will vote with Fifth Third as a single class on all matters submitted to a vote of Fifth Third, as the sole common stockholder of the Company. Thus, the voting rights that will be conferred upon the holders of Company Series C Preferred Stock by the Charter Amendment will continue to apply with respect to the Company, and not Fifth Third, following completion of the Merger. At the Effective Time, each option granted by the Company to purchase shares of Company Common Stock (the "Company Options") will be converted into an option to purchase shares of Fifth Third Common Stock on the same terms and conditions as were applicable to such Company Options prior to the Merger, subject to certain adjustments to the exercise price and the number of shares of Fifth Third Common Stock issuable upon exercise of such option in accordance with the Merger Agreement. In addition, each Company restricted stock award, restricted stock unit and performance-based award (the "Company Equity Awards") that remains unvested and would not automatically vest by its terms at the Effective Time will be assumed by Fifth Third and converted into a number of shares of Fifth Third Common Stock (the "Assumed Equity Awards") with such shares being subject to certain adjustments in accordance with the Merger Agreement but otherwise remaining subject to the same terms and conditions as applicable immediately prior to such conversion. Each Company Equity Award that is outstanding immediately prior to the Effective Time that is not assumed under the Merger Agreement will be canceled and converted automatically into the right to receive the Merger Consideration. On September 18, 2018, the Company received the requisite approvals of its common stockholders for the Merger. The Merger is subject to regulatory approvals and certain other customary closing conditions.

Restrictions on Cash and Due Fr

Restrictions on Cash and Due From Banks	12 Months Ended
	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Restrictions on Cash and Due From Banks	Restrictions on Cash and Due From Banks MB Financial Bank is required to maintain reserve balances in cash or on deposit with the Federal Reserve Bank, based on a percentage of deposits. The total of those required reserve balances was approximately $205.0 million and $210.0 million at December 31, 2018 and 2017 , respectively. The nature of the Company’s business requires that it maintain amounts with banks and federal funds sold which, at times, may exceed federally insured limits. Management monitors these correspondent relationships and the Company has not experienced any losses in such accounts.

Investment Securities

Investment Securities	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities Amortized cost and fair value of investment securities, excluding marketable equity securities and non-marketable FHLB and FRB stock, were as follows as of the dates indicated (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2018 Available for Sale U.S. Treasury securities $ 75,139 $ 2 $ — $ 75,141 U.S. Government sponsored agencies and enterprises 5,076 — (52 ) 5,024 States and political subdivisions 332,048 9,850 (421 ) 341,477 Residential mortgage-backed securities 1,414,335 3,888 (15,770 ) 1,402,453 Commercial mortgage-backed securities 31,572 80 (65 ) 31,587 Total Available for Sale 1,858,170 13,820 (16,308 ) 1,855,682 Held to Maturity States and political subdivisions 887,028 18,896 (1,079 ) 904,845 Residential mortgage-backed securities 14,656 159 — 14,815 Total Held to Maturity 901,684 19,055 (1,079 ) 919,660 Total $ 2,759,854 $ 32,875 $ (17,387 ) $ 2,775,342 December 31, 2017 Available for Sale U.S. Government sponsored agencies and enterprises $ 23,013 $ 3 $ (9 ) $ 23,007 States and political subdivisions 363,813 15,998 (486 ) 379,325 Residential mortgage-backed securities 861,594 3,035 (11,930 ) 852,699 Commercial mortgage-backed securities 71,554 612 (131 ) 72,035 Corporate bonds 70,155 84 (42 ) 70,197 Equity securities (1) 11,236 — (173 ) 11,063 Total Available for Sale 1,401,365 19,732 (12,771 ) 1,408,326 Held to Maturity States and political subdivisions 878,400 32,559 (447 ) 910,512 Residential mortgage-backed securities 80,682 1,261 — 81,943 Total Held to Maturity 959,082 33,820 (447 ) 992,455 Total $ 2,360,447 $ 53,552 $ (13,218 ) $ 2,400,781 (1) Reflected in marketable equity securities on the consolidated balance sheet following the adoption of the new guidance under ASC Topic 825 "Financial Instruments" on January 1, 2018. The increase in investment securities was principally due to investments in residential mortgage-backed securities in the year ended December 31, 2018. The Company has no direct exposure to the State of Illinois, but approximately 20% of the state and political subdivisions portfolio consists of securities issued by municipalities located in Illinois as of December 31, 2018 . Approximately 95% of such securities were general obligation issues, and 26% were insured or had another form of credit enhancement as of December 31, 2018 . Unrealized losses on investment securities by length of time in a continuous unrealized loss position and the fair value of the related securities at December 31, 2018 were as follows (in thousands): Less Than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses Available for Sale U.S. Government sponsored agencies and enterprises $ — $ — $ 5,024 $ (52 ) $ 5,024 $ (52 ) States and political subdivisions 6,725 (13 ) 23,328 (408 ) 30,053 (421 ) Residential mortgage-backed securities 465,935 (2,605 ) 517,954 (13,165 ) 983,889 (15,770 ) Commercial mortgage-backed securities 11,885 (28 ) 11,641 (37 ) 23,526 (65 ) Total Available for Sale 484,545 (2,646 ) 557,947 (13,662 ) 1,042,492 (16,308 ) Held to Maturity States and political subdivisions 70,076 (475 ) 26,333 (604 ) 96,409 (1,079 ) Total $ 554,621 $ (3,121 ) $ 584,280 $ (14,266 ) $ 1,138,901 $ (17,387 ) Unrealized losses on investment securities by length of time in a continuous unrealized loss position and the fair value of the related securities at December 31, 2017 were as follows (in thousands): Less Than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses Available for Sale U.S. Government sponsored agencies and enterprises $ 5,111 $ (9 ) $ — $ — $ 5,111 $ (9 ) States and political subdivisions 9,016 (29 ) 18,754 (457 ) 27,770 (486 ) Residential mortgage-backed securities 256,769 (1,853 ) 407,224 (10,077 ) 663,993 (11,930 ) Commercial mortgage-backed securities 19,483 (20 ) 14,583 (111 ) 34,066 (131 ) Corporate bonds 7,052 (8 ) 9,963 (34 ) 17,015 (42 ) Equity securities 11,063 (173 ) — — 11,063 (173 ) Total Available for Sale 308,494 (2,092 ) 450,524 (10,679 ) 759,018 (12,771 ) Held to Maturity States and political subdivisions 45,499 (257 ) 12,561 (190 ) 58,060 (447 ) Total $ 353,993 $ (2,349 ) $ 463,085 $ (10,869 ) $ 817,078 $ (13,218 ) The total number of security positions in the investment portfolio in an unrealized loss position at December 31, 2018 was 571 compared to 471 at December 31, 2017 . The increase in the total number of security positions in a continuous unrealized loss position and the increase in the unrealized losses from December 31, 2017 to December 31, 2018 was due to the increases in market interest rates. Changes in market interest rates can significantly influence the fair value of securities, and the fair value of our municipal securities portfolio would decline substantially if interest rates increase materially. Declines in the fair value of available for sale securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses to the extent the impairment is related to credit losses. The amount of the impairment related to other factors is recognized in other comprehensive income. In estimating other-than-temporary impairment losses, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than cost, (ii) the financial condition and near-term prospects of the issuer, and (iii) whether the Company is more likely than not to sell the security before recovery of its cost basis. As of December 31, 2018 , management did not have the intent to sell any of the securities in the table above and believed that it was more likely than not that the Company will not have to sell any such securities before a recovery of cost. The fair value is expected to recover as the securities approach their maturity date or repricing date or if market yields for such investments decline. Accordingly, as of December 31, 2018 , management believes the impairments detailed in the table above are temporary. Net gains (losses) recognized on investment securities were as follows (in thousands): For the Years Ended December 31, 2018 2017 2016 Realized gains $ 424 $ 617 $ 614 Realized losses (680 ) (55 ) (167 ) Net (losses) gains $ (256 ) $ 562 $ 447 The amortized cost and fair value of investment securities as of December 31, 2018 by contractual maturity are shown below. Maturities may differ from contractual maturities in mortgage-backed securities because the mortgages underlying the securities may be called or repaid without any penalties. Therefore, mortgage-backed securities are not included in the maturity categories in the following maturity summary. Amortized Fair (In thousands) Cost Value Available for sale: Due in one year or less $ 44,341 $ 44,613 Due after one year through five years 200,973 204,252 Due after five years through ten years 35,048 35,394 Due after ten years 131,901 137,383 Residential and commercial mortgage-backed securities 1,445,907 1,434,040 Total Available for Sale 1,858,170 1,855,682 Held to maturity: Due in one year or less 58,826 59,042 Due after one year through five years 153,790 158,329 Due after five years through ten years 242,049 248,276 Due after ten years 432,363 439,198 Residential mortgage-backed securities 14,656 14,815 Total Held to Maturity 901,684 919,660 Total $ 2,759,854 $ 2,775,342 Investment securities with carrying amounts of $795.5 million and $726.1 million at December 31, 2018 and 2017 , respectively, were pledged as collateral on public deposits and for other purposes as required or permitted by law, while only $694.6 million and $625.2 million were required to be pledged at December 31, 2018 and 2017 , respectively. Investment securities held to maturity with a carrying amount of $2.6 million were transferred to the available for sale portfolio and subsequently sold during the first quarter of 2018. These investment securities were obligations of states and political subdivisions that were downgraded and no longer met our credit criteria.

Loans

Loans	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Loans	Loans Loans consist of the following at (in thousands): December 31, 2018 2017 Commercial $ 5,169,763 $ 4,786,180 Commercial collateralized by assignment of lease payments 2,084,170 2,113,135 Commercial real estate 3,720,255 4,147,529 Residential real estate 1,397,598 1,432,458 Construction real estate 506,837 406,849 Indirect vehicle 817,108 667,928 Home equity 172,890 219,098 Other consumer 82,461 73,141 Gross loans, excluding purchased credit-impaired loans 13,951,082 13,846,318 Purchased credit-impaired loans 84,101 119,744 Total loans $ 14,035,183 $ 13,966,062 Loans are made to individuals as well as commercial and tax exempt entities. Specific loan terms vary as to interest rate, repayment, and collateral requirements based on the type of loan requested and the credit worthiness of the prospective borrower. Except for commercial loans collateralized by assignment of lease payments, asset-based loans, residential real estate loans, and indirect vehicle loans, credit risk tends to be geographically concentrated in that a majority of the loan customers are located in Illinois. The Company's extension of credit is governed by its Credit Risk Policy, which was established to control the quality of the Company's loans. This policy is reviewed and approved by the Enterprise Risk Committee of the Company's Board of Directors on an annual basis. Commercial Loans. Commercial credit is extended mostly to middle market customers. Such credits are typically comprised of working capital loans, loans for physical asset expansion, asset acquisition loans and other business loans. Loans to closely held businesses will generally be guaranteed in full or for a significant amount by the businesses' principal owners. Commercial loans are made based primarily on the historical cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not perform as forecasted and collateral securing loans may fluctuate in value due to economic or individual performance factors. Minimum standards and underwriting guidelines have been established for all commercial loan types. Asset-based loans, also included in commercial loans, are made to businesses with the primary source of repayment derived from payments on the related assets securing the loan. Collateral for these loans may include accounts receivable, inventory and equipment, and is monitored regularly to ensure ongoing sufficiency of collateral coverage and quality. The primary risk for these loans is a significant decline in collateral values due to general market conditions. Loan terms that mitigate these risks include typical industry amortization schedules, percentage of collateral advances, maintenance of cash collateral accounts and regular asset monitoring. Because of the national scope of our asset-based lending, the risk of these loans is also diversified by geography. Commercial Loans Collateralized by Assignment of Lease Payments ("Lease Loans"). The Company makes lease loans to lessors where the underlying leases are with both investment grade and non-investment grade companies. Investment grade lessees are companies rated in one of the four highest categories by Moody's Investor Services. Whether or not companies fall into this category, each lease loan is considered on its individual merit based on the financial wherewithal of the lessee using financial information available at the time of underwriting. In addition, leases that transfer substantially all of the benefits and risk related to the equipment ownership are classified as direct finance leases and are included in lease loans. Commercial Real Estate Loans. Commercial real estate loans are subject to underwriting standards and processes similar to commercial loans. These loans are viewed primarily as property income based loans and the repayment of these loans is largely dependent on the successful operation of the property, which also serves as collateral for the loan. In addition, $1.2 billion and $1.3 billion of commercial real estate loans at December 31, 2018 and 2017, respectively, were secured by owner-occupied properties where the primary source of repayment is the cash flow from the ongoing operations and activities conducted by the owner of the property. Loan performance may be adversely affected by factors impacting the general economy or conditions specific to the real estate market such as geographic location and/or property type. Construction Real Estate Loans. The Company defines construction loans as loans where the loan proceeds are monitored by the Company and used exclusively for the improvement of real estate in which the Company holds a mortgage. Due to the inherent risk in this type of loan, these loans are subject to other industry specific policy guidelines outlined in the Company's Credit Risk Policy. Consumer Related Loans. The Company originates direct and indirect consumer loans, including residential real estate, home equity lines and loans, credit cards, and indirect vehicle loans (motorcycle, marine, recreational, and powersports vehicles). Each loan type is underwritten based upon several factors including debt to income, type of collateral and loan to collateral value, credit history, and the Company's relationship with the borrower. Indirect loan and credit card underwriting involves the use of risk-based pricing in the underwriting process. Purchased credit-impaired loans. Purchased credit-impaired loans are accounted for under ASC Topic 310-30, which include purchased credit-impaired loans acquired through business combinations, FDIC-assisted transactions, and repurchase transactions with the Government National Mortgage Association ("GNMA"). The loans repurchased from GNMA were originally sold by the Company with servicing retained and subsequently became delinquent. These loans are also insured by the Federal Housing Administration (commonly referred to as "FHA") or the U.S. Department of Veterans Affairs (commonly referred to as "VA") where the Company would be able to recover the principal balance of these loans. All repurchases from GNMA are at the Company's discretion. Loans to executive officers and directors. Loans outstanding to executive officers and directors of the Company and MB Financial Bank, including companies in which they have management control or controlling beneficial ownership, at December 31, 2018 and 2017 , were approximately $40.7 million and $39.5 million , respectively. Total advances on loans outstanding to executive officers and directors, including companies in which they have management control or controlling beneficial ownership, were $16.5 million , and total repayments were $15.4 million during the year ended December 31, 2018 . In the opinion of management, these loans have similar terms to other customer loans and do not present more than normal risk of collection. Pledged loans. A collateral pledge agreement exists whereby at all times, the Company must keep on hand, free of all other pledges, liens, and encumbrances, loans with unpaid principal balances aggregating no less than 160% for qualifying first mortgage loans, 170% for home equity loans, 157% for qualifying commercial real estate loan, and 106% for loans held for sale, of the outstanding advances from the Federal Home Loan Bank. As of December 31, 2018 and 2017 , the Company had $3.8 billion and $4.7 billion , respectively, of loans pledged as collateral for Federal Home Loan Bank advances and third party letters of credit, while only $3.2 billion and $3.1 billion were required to be pledged at December 31, 2018 and 2017 , respectively. The Company also has a collateral pledge agreement with the Federal Reserve Bank. As of December 31, 2018 and 2017, the Company had $771.8 million and $902.2 million , respectively, of loans pledged as collateral at the Federal Reserve Bank for the discount window as a backup liquidity funding source. The following table presents the contractual aging of the recorded investment in past due loans by class of loans as of December 31, 2018 and 2017 (in thousands): Current 30-59 Days 60-89 Days Loans Past Due Total Total December 31, 2018 Commercial $ 5,160,023 $ 474 $ — $ 9,266 $ 9,740 $ 5,169,763 Commercial collateralized by assignment of lease payments 2,034,344 40,487 6,729 2,610 49,826 2,084,170 Commercial real estate: Health care 617,428 — — — — 617,428 Industrial 834,983 — — 2,814 2,814 837,797 Multifamily 514,234 1,925 — — 1,925 516,159 Retail 461,063 — — 1,232 1,232 462,295 Office 432,977 — — 120 120 433,097 Other 846,361 897 278 5,943 7,118 853,479 Residential real estate 1,373,677 7,155 2,103 14,663 23,921 1,397,598 Construction real estate 504,975 1,862 — — 1,862 506,837 Indirect vehicle 807,514 6,903 1,773 918 9,594 817,108 Home equity 169,801 990 179 1,920 3,089 172,890 Other consumer 82,147 134 150 30 314 82,461 Gross loans, excluding purchased credit-impaired loans 13,839,527 60,827 11,212 39,516 111,555 13,951,082 Purchased credit-impaired loans 45,710 7,463 3,988 26,940 38,391 84,101 Total loans $ 13,885,237 $ 68,290 $ 15,200 $ 66,456 $ 149,946 $ 14,035,183 Non-performing loan aging $ 27,672 $ 2,121 $ 1,062 $ 39,516 $ 42,699 $ 70,371 December 31, 2017 Commercial $ 4,769,244 $ 1,702 $ 6,926 $ 8,308 $ 16,936 $ 4,786,180 Commercial collateralized by assignment of lease payments 2,099,246 11,320 1,878 691 13,889 2,113,135 Commercial real estate: Health care 710,722 — — — — 710,722 Industrial 908,394 — — 755 755 909,149 Multifamily 601,844 688 — 732 1,420 603,264 Retail 503,224 — — 474 474 503,698 Office 453,960 — 956 1,454 2,410 456,370 Other 956,181 7,035 76 1,034 8,145 964,326 Residential real estate 1,410,473 12,359 1,907 7,719 21,985 1,432,458 Construction real estate 404,595 2,254 — — 2,254 406,849 Indirect vehicle 661,028 4,905 1,083 912 6,900 667,928 Home equity 210,831 3,161 1,073 4,033 8,267 219,098 Other consumer 72,846 202 36 57 295 73,141 Gross loans, excluding purchased credit-impaired loans 13,762,588 43,626 13,935 26,169 83,730 13,846,318 Purchased credit-impaired loans 63,937 8,749 3,997 43,061 55,807 119,744 Total loans $ 13,826,525 $ 52,375 $ 17,932 $ 69,230 $ 139,537 $ 13,966,062 Non-performing loan aging $ 36,879 $ 8,799 $ 4,961 $ 26,169 $ 39,929 $ 76,808 The following table presents the recorded investment in non-accrual loans and loans past due ninety days or more and still accruing by class of loans, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): 2018 2017 Loans past due Loans past due Non-accrual 90 days or more and still accruing Non-accrual 90 days or more and still accruing Commercial $ 16,509 $ — $ 14,001 $ 3,500 Commercial collateralized by assignment of lease payments 1,551 2,398 490 531 Commercial real estate: Health care — — — — Industrial 2,814 — 8,807 — Multifamily 33 — 860 — Office 416 — 2,772 — Retail 1,232 — 590 — Other 6,710 — 8,016 190 Residential real estate 21,829 327 18,374 1,210 Construction real estate — — — — Indirect vehicle 4,176 — 3,019 81 Home equity 12,341 — 14,305 — Other consumer 5 30 4 58 Total $ 67,616 $ 2,755 $ 71,238 $ 5,570 The reduction in interest income associated with loans on non-accrual status was approximately $3.2 million , $2.1 million , and $3.0 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. The Company utilizes an internal asset classification system as a means of reporting problem and potential problem loans. Under the Company's risk rating system, the Company classifies potential problem and problem loans as “Special Mention,” “Substandard,” and “Doubtful.” Substandard loans include those characterized by the distinct possibility that the Company will sustain some loss if the deficiencies are not corrected. Loans classified as Doubtful have all the weaknesses inherent in those classified as Substandard with the added characteristic that the weaknesses present make collection or liquidation in full, on the basis of currently existing facts, conditions and values, highly questionable and improbable. Loans that do not currently expose the Company to sufficient risk to warrant classification in one of the aforementioned categories but possess weaknesses that deserve management's close attention are deemed to be Special Mention. Loans rated but not adversely classified are deemed to be Pass. Risk ratings are updated any time the situation warrants and at least annually. Loans not rated are included in groups of homogeneous loans with similar risk and loss characteristics and are not included in the table below. The following tables present the risk category of loans by class of loans based on the most recent analysis performed, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): Pass Special Substandard Doubtful Total December 31, 2018 Commercial $ 4,785,792 $ 194,314 $ 189,657 $ — $ 5,169,763 Commercial collateralized by assignment of lease payments 2,055,391 22,768 6,011 — 2,084,170 Commercial real estate: Health care 462,399 48,711 106,318 — 617,428 Industrial 799,673 23,834 14,290 — 837,797 Multifamily 509,270 1,242 5,647 — 516,159 Retail 436,923 9,939 15,433 — 462,295 Office 410,122 3,119 19,856 — 433,097 Other 753,334 46,337 53,808 — 853,479 Construction real estate 504,246 2,247 344 — 506,837 Total $ 10,717,150 $ 352,511 $ 411,364 $ — $ 11,481,025 December 31, 2017 Commercial $ 4,535,111 $ 147,232 $ 103,837 $ — $ 4,786,180 Commercial collateralized by assignment of lease payments 2,095,668 7,527 9,940 — 2,113,135 Commercial real estate: Health care 640,751 33,672 36,299 — 710,722 Industrial 885,524 12,411 11,214 — 909,149 Multifamily 595,818 146 7,300 — 603,264 Retail 492,830 8,326 2,542 — 503,698 Office 452,902 696 2,772 — 456,370 Other 891,703 37,682 34,941 — 964,326 Construction real estate 406,849 — — — 406,849 Total $ 10,997,156 $ 247,692 $ 208,845 $ — $ 11,453,693 Approximately $29.3 million and $35.6 million of the substandard and doubtful loans were non-performing as of December 31, 2018 and 2017 , respectively. For residential real estate, home equity, indirect vehicle and other consumer loan classes, the Company also evaluates credit quality based on the aging status of the loan, which was previously presented, and by payment activity. The following table presents the recorded investment in those loan classes based on payment activity, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): Performing Non-performing Total December 31, 2018 Residential real estate $ 1,375,442 $ 22,156 $ 1,397,598 Indirect vehicle 812,932 4,176 817,108 Home equity 160,549 12,341 172,890 Other consumer 82,426 35 82,461 Total $ 2,431,349 $ 38,708 $ 2,470,057 December 31, 2017 Residential real estate $ 1,412,874 $ 19,584 $ 1,432,458 Indirect vehicle 664,828 3,100 667,928 Home equity 204,793 14,305 219,098 Other consumer 73,079 62 73,141 Total $ 2,355,574 $ 37,051 $ 2,392,625 The recorded investment in residential mortgage loans secured by residential real estate properties (including purchased credit-impaired loans) for which foreclosure proceedings are in process totaled $58.8 million and $43.6 million at December 31, 2018 and 2017 , respectively. The following tables present loans individually evaluated for impairment by class of loans, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): December 31, 2018 Unpaid Recorded Partial Allowance for Average Interest With no related allowance recorded: Commercial $ 7,508 $ 4,729 $ 2,779 $ — $ 9,971 $ 222 Commercial collateralized by assignment of lease payments — — — — — — Commercial real estate: Health care — — — — — — Industrial 3,429 2,814 615 — 1,760 — Multifamily — — — — — — Retail — — — — — — Office — — — — — — Other — — — — 820 52 Residential real estate 3,793 3,755 38 — 2,995 — Construction real estate — — — — — — Indirect vehicle 695 395 300 — 692 41 Home equity 161 161 — — 60 — Other consumer — — — — — — With an allowance recorded: Commercial 32,078 10,576 21,502 1,612 12,993 256 Commercial collateralized by assignment of lease payments — — — — 83 — Commercial real estate: Health care — — — — 267 28 Industrial — — — — 1,590 8 Multifamily — — — — — — Retail — — — — — — Office — — — — — — Other 4,766 4,766 — 413 3,502 124 Residential real estate 18,966 17,159 1,807 1,454 18,158 32 Construction real estate — — — — — — Indirect vehicle — — — — — — Home equity 28,897 26,150 2,747 1,392 28,008 47 Other consumer — — — — — — Total $ 100,293 $ 70,505 $ 29,788 $ 4,871 $ 80,899 $ 810 December 31, 2017 Unpaid Recorded Partial Allowance for Average Interest With no related allowance recorded: Commercial $ 8,312 $ 7,771 $ 541 $ — $ 5,595 $ 95 Commercial collateralized by assignment of lease payments — — — — 301 — Commercial real estate: Health care — — — — — — Industrial — — — — 1,260 8 Multifamily — — — — 1,261 29 Retail — — — — 814 27 Office 527 527 — — 1,426 18 Other 10,597 10,597 — — 2,312 128 Residential real estate 1,950 1,912 38 — 483 — Construction real estate — — — — — — Indirect vehicle 408 202 206 — 411 26 Home equity 81 81 — — 376 — Other consumer — — — — — — With an allowance recorded: Commercial 7,418 7,418 — 2,315 7,668 277 Commercial collateralized by assignment of lease payments — — — — 126 14 Commercial real estate: Health care — — — — — — Industrial 8,339 8,317 22 2,669 3,215 171 Multifamily 568 568 — 320 426 — Retail — — — — 1,345 28 Office 2,293 2,277 16 752 636 4 Other — — — — 29 — Residential real estate 21,380 19,014 2,366 2,158 17,616 25 Construction real estate — — — — — — Indirect vehicle — — — — — — Home equity 30,762 28,286 2,476 2,200 27,982 54 Other consumer — — — — — — Total $ 92,635 $ 86,970 $ 5,665 $ 10,414 $ 73,282 $ 904 Average impaired loans for the years ended December 31, 2018 , 2017 and 2016 were $80.9 million , $73.3 million and $87.6 million , respectively. Interest income recognized on impaired loans was $810 thousand , $904 thousand and $52 thousand for the years ended December 31, 2018 , 2017 and 2016 , respectively. Impaired loans as of December 31, 2018 and 2017 included accruing restructured loans of $22.8 million and $28.6 million , respectively, that have been modified and were performing in accordance with their modified terms as of those dates. In addition, impaired loans as of December 31, 2018 and 2017 included non-performing restructured loans of $22.0 million and $30.8 million , respectively. Loans may be restructured in an effort to maximize collections from financially distressed borrowers. We use various restructuring techniques, including, but not limited to, deferring past due interest or principal, implementing an A/B note structure, redeeming past due taxes, reducing interest rates, extending maturities and modifying amortization schedules. Residential real estate loans are restructured in an effort to minimize losses while allowing borrowers to remain in their primary residences when possible. A loan classified as a troubled debt restructuring will no longer be included in the troubled debt restructuring disclosures in the years after the restructuring if the loan performs in accordance with the terms specified by the restructuring agreement and the interest rate specified in the restructuring agreement represents a market rate at the time of modification. The specified interest rate is considered a market rate when the interest rate is equal to or greater than the rate the Company is willing to accept at the time of restructuring for a new loan with comparable risk. If there are concerns that the borrower will not be able to meet the modified terms of the loan, the loan will continue to be included in the troubled debt restructuring disclosures. Impairment analyses on commercial-related loans classified as troubled debt restructurings are performed in conjunction with the normal allowance for loan and lease losses process. Consumer loans classified as troubled debt restructurings are aggregated in two pools that share common risk characteristics, home equity and residential real estate loans, with impairment measured on a quarterly basis based on the present value of expected future cash flows discounted at the loan's effective interest rate. The following table presents loans that were restructured during the year ended December 31, 2018 (dollars in thousands): December 31, 2018 Number of Pre-Modification Recorded Post-Modification Recorded Charge-offs and Performing: Commercial 2 $ 69 $ 69 $ — Commercial real estate: Residential real estate 2 220 220 21 Home equity 2 128 128 7 Total 6 $ 417 $ 417 $ 28 Non-Performing: Commercial 1 $ 750 $ 750 $ — Commercial real estate: Residential real estate 21 3,525 3,525 1,216 Indirect vehicle 45 290 290 171 Home equity 7 606 606 233 Total 74 $ 5,171 $ 5,171 $ 1,620 The following table presents loans that were restructured during the year ended December 31, 2017 (dollars in thousands): December 31, 2017 Number of Pre-Modification Recorded Post-Modification Recorded Charge-offs and Performing: Commercial 5 $ 2,491 $ 2,491 $ 373 Commercial real estate: Industrial 3 3,174 3,174 — Retail 2 337 337 — Office 1 548 548 — Other 4 4,171 4,171 — Residential real estate 10 1,744 1,744 230 Home equity 5 122 122 9 Total 30 $ 12,587 $ 12,587 $ 612 Non-Performing: Commercial 6 $ 1,363 $ 1,363 $ — Commercial real estate: Multifamily 3 290 290 — Retail 1 906 906 — Other 1 554 554 — Residential real estate 35 6,428 6,428 1,733 Indirect vehicle 40 277 277 150 Home equity 5 842 842 76 Total 91 $ 10,660 $ 10,660 $ 1,959 Of the troubled debt restructurings entered into during the year ended December 31, 2018 , none subsequently defaulted during the year. Performing troubled debt restructurings are considered to have defaulted when they become 90 days or more past due post-restructuring or are placed on non-accrual status. The following tables present the troubled debt restructurings activity during the year ended December 31, 2018 (dollars in thousands): Performing Non-performing Beginning balance $ 28,554 $ 30,836 Additions 417 5,171 Charge-offs — (3,369 ) Principal payments, net (8,382 ) (8,238 ) Removals (77 ) (168 ) Transfer to other real estate owned — — Transfers in 3,754 1,473 Transfers out (1,473 ) (3,754 ) Ending balance $ 22,793 $ 21,951 Loans removed from troubled debt restructuring status are those that were restructured in a previous calendar year at a market rate of interest and have performed in compliance with the modified terms. The following table presents the type of modification for loans that have been restructured and the post-modification recorded investment during the year ended December 31, 2018 (dollars in thousands): December 31, 2018 Extended Maturity, Extended Amortization and Reduction of Interest Rate Extended Maturity and/or Amortization Extended Maturity, Extended Amortization, and Delay in Payments Delay in Payments and/or Reduction of Interest Rate Total Commercial $ — $ 750 $ 69 $ — $ 819 Residential real estate 2,472 862 — 411 3,745 Indirect vehicle — — — 290 290 Home equity 293 441 — — 734 Total $ 2,765 $ 2,053 $ 69 $ 701 $ 5,588 Activity in the allowance for loan and lease losses was as follows (in thousands): Year Ended December 31, 2018 2017 2016 Balance at beginning of year $ 159,408 $ 141,842 $ 131,508 Provision for credit losses 47,201 21,593 19,563 Charge-offs: Commercial 30,173 2,323 2,126 Commercial collateralized by assignment of lease payments 7,997 3,397 6,740 Commercial real estate 6,396 1,466 2,851 Residential real estate 1,100 932 1,356 Construction real estate — — 593 Indirect vehicle 7,656 5,433 3,505 Home equity 1,299 1,314 1,662 Other consumer 1,321 1,707 1,778 Total charge-offs 55,942 16,572 20,611 Recoveries: Commercial 2,222 3,806 2,434 Commercial collateralized by assignment of lease payments 1,275 775 550 Commercial real estate 1,956 2,817 3,729 Residential real estate 778 724 1,210 Construction real estate 695 774 142 Indirect vehicle 3,124 2,282 1,837 Home equity 817 778 756 Other consumer 522 589 724 Total recoveries 11,389 12,545 11,382 Net charge-offs 44,553 4,027 9,229 Allowance for credit losses 162,056 159,408 141,842 Allowance for unfunded credit commitments (478 ) (1,698 ) (2,476 ) Balance at December 31, $ 161,578 $ 157,710 $ 139,366 The following table presents the activity in the allowance for credit losses, balance in allowance for credit losses and recorded investment in loans by portfolio segment and based on impairment method as of December 31, 2018 and 2017 (in thousands): Commercial Commercial collateralized by assignment of lease payments Commercial real estate Residential real estate Construction real estate Indirect vehicle Home equity Other Consumer Unfunded Commitments Total December 31, 2018 Allowance for credit losses: Beginning balance $ 46,267 $ 13,007 $ 63,429 $ 7,012 $ 15,501 $ 4,728 $ 5,296 $ 2,470 $ 1,698 $ 159,408 Charge-offs 30,173 7,997 6,396 1,100 — 7,656 1,299 1,321 — 55,942 Recoveries 2,222 1,275 1,956 778 695 3,124 817 522 — 11,389 Provision 29,751 7,038 4,484 (1,577 ) 7,036 2,996 (1,424 ) 117 (1,220 ) 47,201 Ending balance $ 48,067 $ 13,323 $ 63,473 $ 5,113 $ 23,232 $ 3,192 $ 3,390 $ 1,788 $ 478 $ 162,056 Ending allowance balance attributable to loans: Individually evaluated for impairment $ 1,612 $ — $ 413 $ 1,454 $ — $ — $ 1,392 $ — $ 50 $ 4,921 Collectively evaluated for impairment 46,271 13,323 62,765 3,659 23,232 3,192 1,998 1,788 428 156,656 Acquired and accounted for under ASC Topic 310-30 (1) 184 — 295 — — — — — — 479 Total ending allowance balance $ 48,067 $ 13,323 $ 63,473 $ 5,113 $ 23,232 $ 3,192 $ 3,390 $ 1,788 $ 478 $ 162,056 Loans: Individually evaluated for impairment $ 15,305 $ — $ 7,580 $ 20,914 $ — $ 395 $ 26,311 $ — $ — $ 70,505 Collectively evaluated for impairment 5,154,458 2,084,170 3,712,675 1,376,684 506,837 816,713 146,579 82,461 — 13,880,577 Acquired and accounted for under ASC Topic 310-30 (1) 7,245 — 20,725 44,176 3,020 — 8,081 854 — 84,101 Total ending loans balance $ 5,177,008 $ 2,084,170 $ 3,740,980 $ 1,441,774 $ 509,857 $ 817,108 $ 180,971 $ 83,315 $ — $ 14,035,183 December 31, 2017 Allowance for credit losses: Beginning balance $ 44,661 $ 12,238 $ 51,807 $ 5,971 $ 14,758 $ 3,421 $ 4,689 $ 1,821 $ 2,476 $ 141,842 Charge-offs 2,323 3,397 1,466 932 — 5,433 1,314 1,707 — 16,572 Recoveries 3,806 775 2,817 724 774 2,282 778 589 — 12,545 Provision 123 3,391 10,271 1,249 (31 ) 4,458 1,143 1,767 (778 ) 21,593 Ending balance $ 46,267 $ 13,007 $ 63,429 $ 7,012 $ 15,501 $ 4,728 $ 5,296 $ 2,470 $ 1,698 $ 159,408 Ending allowance balance attributable to loans: Individually evaluated for impairment $ 2,315 $ — $ 3,741 $ 2,158 $ — $ — $ 2,200 $ — $ 437 $ 10,851 Collectively evaluated for impairment 43,861 13,007 58,637 4,854 15,466 4,728 3,096 2,470 1,261 147,380 Acquired and accounted for under ASC Topic 310-30 (1) 91 — 1,051 — 35 — — — — 1,177 Total ending allowance balance $ 46,267 $ 13,007 $ 63,429 $ 7,012 $ 15,501 $ 4,728 $ 5,296 $ 2,470 $ 1,698 $ 159,408 Loans: Individually evaluated for impairment $ 15,189 $ — $ 22,286 $ 20,926 $ — $ 202 $ 28,367 $ — $ — $ 86,970 Collectively evaluated for impairment 4,770,991 2,113,135 4,125,243 1,411,532 406,849 667,726 190,731 73,141 — 13,759,348 Acquired and accounted for under ASC Topic 310-30 (1) 13,667 — 25,490 63,137 5,220 — 10,559 1,671 — 119,744 Total ending loans balance $ 4,799,847 $ 2,113,135 $ 4,173,019 $ 1,495,595 $ 412,069 $ 667,928 $ 229,657 $ 74,812 $ — $ 13,966,062 (1) Loans acquired in business combinations and accounted for under ASC Topic 310-30 “Receivables — Loans and Debt Securities Acquired with Deteriorated Credit Quality.” Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date without a carryover of the related allowance for loan and lease losses. These acquired loans are segregated into three types: pass rated loans with no discount attributable to credit quality, non-impaired loans with a discount attributable at least in part to credit quality, and impaired loans with evidence of significant credit deterioration. • Pass rated loans (typically performing loans) are accounted for in accordance with ASC Topic 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination. • Non-impaired loans (typically performing substandard loans) are accounted for in accordance with ASC Topic 310-30 if they display at least some level of credit deterioration since origination. • Impaired loans (typically substandard loans on non-accrual status) are accounted for in accordance with ASC Topic 310-30 as they display significant credit deterioration since origination. For pass rated loans (non-purchased credit-impaired loans), the difference between the estimated fair value of the loans and the principal outstanding is accreted over the remaining life of the loans. In accordance with ASC 310-30, for both purchased non-impaired loans and purchased credit-impaired loans, the loans are pooled by loan type and the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan pools when there is a reasonable expectation about the amount and timing of such cash flows. Substantially all of the loans acquired in FDIC-assisted transactions displayed at least some level of credit deterioration and as such are included as non-impaired and impaired loans as described immediately above. Changes in the accretable yield for loans acquired and accounted for under ASC Topic 310-30 were as follows for the years ended December 31, 2018 and 2017 (in thousands): Year Ended December 31, 2018 2017 Balance at beginning of period $ 12,069 $ 16,050 Purchases — 43 Accretion (8,270 ) (12,500 ) Other (1) 2,125 8,476 Balance at end of period $ 5,924 $ 12,069 (1) Primarily includes discount transfers from non-accretable discount to accretable discount due to better than expected performance of loan pools acquired and accounted for under ASC Topic 310-30. In our FDIC-assisted transactions, the fair value of purchased credit-impaired loans, on the acquisition date, was determined based on assigned risk ratings, expected cash flows and the fair value of loan collateral. The fair value of loans that were non-impaired was determined based on estimates of losses on defaults and other market factors. Due to the loss-share agreements with the FDIC, we recorded a receivable (FDIC indemnification asset) from the FDIC equal to the present value of the corresponding reimbursement percentages on the estimated losses embedded in the loan portfolio. For other loans acquired through business combinations, the fair value of purchased credit-impaired loans, on the acquisition date, was determined based on assigned risk ratings, expected cash flows and the fair value of loan collateral. The fair value of loans that were non-impaired was determined based on estimates of losses on defaults and other market factors. Loans acquired through a business combination by loan pool type were as follows as of dates indicated (in thousands): Purchased Purchased Non-Credit-Impaired Total December 31, 2018 Covered loans (1) : Consumer related $ 12,071 $ — $ 12,071 Non covered loans: Commercial loans $ 7,245 $ 101,971 $ 109,216 Commercial loans collateralized by assignment of lease payments — 12,324 12,324 Commercial real estate 20,725 460,368 481,093 Construction real estate 3,020 1,587 4,607 Consumer related 4,412 197,377 201,789 Total non-covered loans 35,402 773,627 809,029 Total acquired $ 47,473 $ 773,627 $ 821,100 December 31, 2017 Covered loans (1) : Consumer related $ 14,898 $ — $ 14,898 Non covered loans: Commercial loans $ 13,667 $ 254,027 $ 267,694 Commercial loans collateralized by assignment of lease payments — 35,163 35,163 Commercial real estate 25,490 776,939 802,429 Construction real estate 5,220 5,660 10,880 Consumer related 4,720 276,023 280,743 Total non-covered loans 49,097 1,347,812 1,396,909 Total acquired $ 63,995 $ 1,347,812 $ 1,411,807 (1) Covered loans refer to loans covered under loss-sharing agreements with the FDIC. The remaining loss-share agreements were scheduled to expire between 2019 and 2020. Subsequent to December 31, 2018, the Company exited the loss-share agreements with the FDIC. See Note 25. Subsequent Events. In addition to loans acquired through a business com

Lease Investments

Lease Investments	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Lease Investments	Lease Investments The lease portfolio is comprised of various types of equipment, generally technology related, including computer systems and satellite equipment, material handling and general manufacturing equipment. Lease investments by categories follow (in thousands): December 31, 2018 2017 Direct finance leases: Minimum lease payments $ 453,014 $ 492,953 Estimated unguaranteed residual values 69,721 74,220 Less: unearned income (40,196 ) (41,311 ) Direct finance leases (1) $ 482,539 $ 525,862 Leveraged leases: Minimum lease payments $ — $ 179 Estimated unguaranteed residual values — 10 Less: unearned income — (3 ) Less: related non-recourse debt — (177 ) Leveraged leases (1) $ — $ 9 Operating leases: Equipment, at cost $ 694,416 $ 575,612 Less accumulated depreciation (206,640 ) (166,561 ) Lease investments, net $ 487,776 $ 409,051 (1) Direct finance and leveraged leases are included as commercial loans collateralized by assignment of lease payments for financial statement purposes. Leases that transfer substantially all of the benefits and risk related to the equipment ownership are classified as direct finance leases. If these direct finance leases have non-recourse debt associated with them and meet the additional requirements for a leveraged lease, they are further classified as leveraged leases, and the associated debt is netted with the outstanding balance in the consolidated financial statements. Interest income on direct finance and leveraged leases is recognized using methods which approximate a level yield over the term of the lease. Operating leases are investments in equipment leased to other companies, where the residual component makes up more than 10% of the investment. The Company funds most of the lease equipment purchases internally, but has some loans at other banks which totaled $78.4 million at December 31, 2018 and $76.3 million at December 31, 2017 . The minimum lease payments receivable for the various categories of leases are due as follows (in thousands) for the years ending December 31, Direct Finance Operating Year Leases Leases Total 2018 $ 162,997 $ 93,026 $ 256,023 2019 119,735 76,107 195,842 2020 79,863 57,168 137,031 2021 47,979 44,094 92,073 2022 27,759 28,603 56,362 Thereafter 14,681 35,638 50,319 $ 453,014 $ 334,636 $ 787,650 At December 31, 2018 , the following reflects the residual values for leases by category in the year the initial lease term ends (in thousands): Residual Values Direct End of initial lease term Finance Operating December 31, Leases Leases Total 2019 $ 9,419 $ 17,054 $ 26,473 2020 13,969 21,338 35,307 2021 7,243 30,966 38,209 2022 12,444 22,766 35,210 2023 8,894 21,632 30,526 Thereafter 17,752 41,339 59,091 $ 69,721 $ 155,095 $ 224,816 The lease residual value represents the present value of the estimated fair value of the leased equipment at the termination of the lease. Lease residual values are reviewed annually, and any write-downs for permanent impairments deemed necessary are recorded in the period in which they become known. To mitigate this risk of loss, we seek to diversify both the type of equipment leased and the industries in which the lessees participate. In addition, a portion of our leases are terminal rental adjustment clause or "TRAC" leases where the lessee effectively guarantees the full residual value through a rental adjustment at the end of term or those where partial residual value is guaranteed ("split-TRAC"), which has a limited residual risk. Under a split-TRAC structure, the limited residual risk would be satisfied first by the net sale proceeds of the leased asset. The lessee’s at-risk portion, or top risk, is satisfied last and is subject to repayment as additional rent, if the TRAC amount is not satisfied by the net sale proceeds. Often times, there are several individual lease schedules under one master lease. There were 4,857 leases at December 31, 2018 compared to 4,773 at December 31, 2017 . The average residual value per lease schedule was approximately $46 thousand at December 31, 2018 and $45 thousand at December 31, 2017 . The average residual value per master lease schedule was approximately $192 thousand at December 31, 2018 and $183 thousand at December 31, 2017 . Income from lease financing, net was composed of (in thousands): Years Ended December 31, 2018 2017 2016 Rental income $ 104,889 $ 87,524 $ 69,083 Equipment maintenance contracts revenue, net of cost of sales 27,093 29,697 25,005 Vendor promotional income 16,223 13,475 11,073 Other lease related revenue 14,198 7,461 4,254 Gain on sale of lease payments and leased equipment, net of residual write downs 20,333 12,381 13,241 Income on lease investments, gross 182,736 150,538 122,656 Less: depreciation on operating leases (78,246 ) (63,951 ) (49,170 ) Lease financing, net $ 104,490 $ 86,587 $ 73,486 Extension rents received in excess of residual values are reflected in rental income. Equipment maintenance contracts revenue represents the gross amount of revenue paid for maintenance contracts and other services brokered to customers. The maintenance contracts are serviced by third parties, with the Company maintaining no obligation under the contracts. The cost of sales is the amount paid by the Company to the third party maintenance provider. From time to time, the Company sells minimum lease payments to third parties. Gains on leased equipment periodically result when a lessee renews a lease or purchases the equipment at the end of a lease or the equipment is sold to a third party at a profit. Individual lease transactions can, however, result in a loss. This generally happens when, at the end of a lease, the lessee does not renew the lease or purchase the equipment.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Premises and equipment consisted of (in thousands): December 31, 2018 2017 Land and land improvements $ 76,827 $ 78,329 Buildings 116,558 116,584 Furniture and equipment 185,242 174,778 Buildings and leasehold improvements 85,692 81,589 464,319 451,280 Accumulated depreciation (193,705 ) (164,590 ) Premises and equipment, net $ 270,614 $ 286,690 Depreciation on premises and equipment totaled $32.1 million , $29.0 million , and $25.5 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively.

Goodwill and Intangibles

Goodwill and Intangibles	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and Intangibles The excess of the cost of an acquisition over the fair value of the net assets acquired, including core deposit and client relationship intangibles, consists of goodwill. Under ASC Topic 350, goodwill is subject to at least annual assessments for impairment by applying a fair value based test. The Company reviews goodwill to determine potential impairment annually, or more frequently if events and circumstances indicate that goodwill might be impaired, by comparing the carrying value of the reporting units with the fair value of the reporting units. The Company's annual assessment date is as of December 31. Goodwill is tested for impairment at the reporting unit level. The Company had three reporting units: Banking, Leasing and Mortgage Banking. Based on the Company's 2018 goodwill impairment testing, the fair values of the three reporting units were in excess of their carrying value. On April 12, 2018, the Company announced the discontinuation of its national mortgage origination business, which includes substantially all originations outside of the Company's consumer banking footprint in the Chicagoland area. As a result, the Company recorded an impairment loss in the amount of $3.6 million within the Mortgage Banking segment in the second quarter of 2018. No impairment losses were recognized during the year ended December 31, 2017 or 2016 . The carrying amount of goodwill was $1.0 billion at December 31, 2018 and 2017 . The following table presents the changes in the carrying amount of goodwill as of December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Banking Leasing Mortgage banking Total Banking Leasing Mortgage banking Total Balance at beginning of period $ 959,285 $ 40,640 $ 3,623 $ 1,003,548 $ 960,398 $ 40,640 $ — $ 1,001,038 Goodwill from business combinations — — — — (1,113 ) — 3,623 2,510 Impairment — — (3,623 ) (3,623 ) — — — — Balance at end of period $ 959,285 $ 40,640 $ — $ 999,925 $ 959,285 $ 40,640 $ 3,623 $ 1,003,548 The Company has other intangible assets consisting of core deposit and client relationship intangibles that had a remaining weighted average amortization period of approximately twelve years as of December 31, 2018 . The following table presents the changes in the carrying amount of core deposit and client relationship intangibles, gross carrying amount, accumulated amortization, and net book value as of December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Balance at beginning of period $ 54,766 $ 62,959 Amortization expense (7,852 ) (8,193 ) Balance at end of period $ 46,914 $ 54,766 Gross carrying amount $ 112,820 $ 112,820 Accumulated amortization (65,906 ) (58,054 ) Net book value $ 46,914 $ 54,766 The following presents the estimated amortization expense of other intangible assets (in thousands): Years ending December 31, Amount 2019 $ 5,903 2020 4,870 2021 4,659 2022 3,696 2023 3,483 Thereafter 24,303 $ 46,914

Deposits

Deposits	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Deposits	Deposits The composition of deposits was as follows (in thousands): December 31, 2018 2017 Demand deposit accounts, non-interest bearing $ 6,152,163 $ 6,381,512 NOW and money market accounts 4,982,026 4,954,765 Savings accounts 1,191,498 1,167,810 Certificates of deposit, $250,000 or more 1,344,570 1,506,071 Other certificates of deposit 983,956 948,220 Total $ 14,654,213 $ 14,958,378 Certificates of deposit of $250,000 or more included $909.7 million and $1.1 billion of brokered deposits at December 31, 2018 and 2017 , respectively. Brokered deposits typically consist of smaller individual time certificates that have the same liquidity characteristics and yields consistent with time certificates of $250,000 or more. At December 31, 2018 , the scheduled maturities of certificates of deposit were as follows (in thousands): 2019 $ 1,465,426 2020 609,146 2021 148,640 2022 82,711 2023 21,833 Thereafter 770 $ 2,328,526

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Short-Term Borrowings	Short-Term Borrowings Short-term borrowings were as follows as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018 2017 Weighted Average Weighted Average Cost Amount Cost Amount Customer repurchase agreements 0.80 % $ 312,239 0.27 % $ 232,789 Federal Home Loan Bank advances 2.66 750,000 1.31 625,000 Federal funds purchased 2.76 407,816 1.26 3,250 Line of credit — — — — Total 2.29 % $ 1,470,055 1.03 % $ 861,039 Customer repurchase agreements are agreements in which the Company acquires funds by selling assets to another party under a simultaneous agreement to repurchase the same assets at a specified price and date. The Company enters into repurchase agreements and also offers a demand deposit account product to customers that sweeps their balances in excess of an agreed upon target amount into overnight repurchase agreements. All securities sold under agreements to repurchase are recorded on the face of the balance sheet. The Company pledges mortgage-backed securities as collateral for the repurchase agreements and may be required to provide additional collateral based on the fair value of those securities. The Company had Federal Home Loan Bank ("FHLB") advances with a maturity date less than one year of $750.0 million at December 31, 2018 and $625.0 million at December 31, 2017 . At December 31, 2018 , the interest rate on the advances outstanding on that date ranged from 2.54% to 2.91% with maturities from January 2, 2019 to December 16, 2019 . The Company has loans pledged as collateral on these FHLB advances. See Note 5. Loans of the notes to the consolidated financial statements. Federal funds purchased are funds purchased from other FRB member banks on an overnight basis. On December 18, 2015, the Company entered into a $35.0 million unsecured line of credit with a correspondent bank at the parent company level. Interest was payable at a rate of one month LIBOR + 1.75% . The line of credit matured on June 30, 2018.

Long-term Borrowings

Long-term Borrowings	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-term Borrowings	Long-term Borrowings Long-term borrowings were as follows as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018 2017 Weighted Average Weighted Average Cost Amount Cost Amount Federal Home Loan Bank advances 2.85 % $ 94,147 1.73 % $ 231,317 Notes payable 4.95 82,407 4.14 90,807 Subordinated notes, net of issuance costs 4.00 173,127 4.00 173,034 Term note — — 3.31 10,000 Total 3.91 % $ 349,681 2.97 % $ 505,158 The Company had FHLB advances with original contractual maturities greater than one year of $94.1 million and $231.3 million at December 31, 2018 and 2017 , respectively. As of December 31, 2018 , the advances had fixed terms with interest rates ranging from 2.73% to 5.87% and maturities ranging from April 2021 to April 2035 . The Company has loans pledged as collateral on these FHLB advances. See Note 5. Loans of the notes to the consolidated financial statements. The Company had notes payable to banks totaling $78.4 million and $76.3 million at December 31, 2018 and 2017 , respectively, which as of December 31, 2018 , were accruing interest at rates ranging from 2.25% to 7.25% , with a weighted average rate of 4.86% . Lease investments include equipment with an amortized cost of $92.9 million and $91.9 million at December 31, 2018 and 2017 , respectively, that was pledged as collateral on these notes. The Company also had $4.1 million and $14.5 million at December 31, 2018 and 2017, respectively, in other secured borrowings (included in the notes payable above) with a weighted average rate of 6.59% as of December 31, 2018. On August 24, 2016, the Company assumed a $16.0 million unsecured term loan at the holding company level with a correspondent bank through the merger of American Chartered with and into the Company on that date. Interest was payable at a rate of one month LIBOR + 1.75% , and the loan was to mature on June 30, 2020. Principal payments of $1.0 million were due quarterly until maturity. This loan was prepaid in full in the first quarter of 2018. On November 16, 2017, MB Financial Bank issued $175.0 million in 4.00% fixed-to-floating subordinated notes that mature on December 1, 2027. The subordinated notes bear a fixed interest rate of 4.00% until December 1, 2022 and a variable interest rate of three month LIBOR + 1.873% thereafter until maturity. The subordinated notes are callable on a semi-annual basis beginning on December 1, 2022. The principal payments on long-term borrowings are due as follows (in thousands): Amount Years ending December 31, 2019 $ 38,904 2020 25,242 2021 12,057 2022 5,050 2023 90,387 Thereafter 178,041 Total $ 349,681

Junior Subordinated Notes Issue

Junior Subordinated Notes Issued to Capital Trusts	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Junior Subordinated Notes Issued to Capital Trusts	Junior Subordinated Notes Issued to Capital Trusts The Company has established statutory trusts for the sole purpose of issuing trust preferred securities and related trust common securities. The proceeds from such issuances were used by the trusts to purchase junior subordinated notes of the Company, which are the sole assets of each trust. Concurrently with the issuance of the trust preferred securities, the Company issued guarantees for the benefit of the holders of the trust preferred securities. The Company’s outstanding trust preferred securities qualify, and are treated by the Company, as Tier 2 regulatory capital. Prior to the completion of the American Chartered merger, the trust preferred securities qualified, and were treated by the Company, as Tier 1 regulatory capital. The Company owns all of the common securities of each trust. The trust preferred securities issued by each trust rank equally with the common securities in right of payment, except that if an event of default under the indenture governing the notes has occurred and is continuing, the preferred securities will rank senior to the common securities in right of payment. The table below summarizes the outstanding junior subordinated notes and the related trust preferred securities issued by each trust as of December 31, 2018 (in thousands): MB Financial Capital Trust II MB Financial Capital Trust III MB Financial Capital Trust IV Junior Subordinated Notes: Principal balance $ 36,083 $ 10,310 $ 20,619 Annual interest rate 3-mo LIBOR + 1.40% 3-mo LIBOR + 1.50% 3-mo LIBOR + 1.52% Stated maturity date September 15, 2035 September 23, 2036 September 15, 2036 Call date December 15, 2010 September 23, 2011 September 15, 2011 Trust Preferred Securities: Face Value $ 35,000 $ 10,000 $ 20,000 Annual distribution rate 3-mo LIBOR + 1.40% 3-mo LIBOR + 1.50% 3-mo LIBOR + 1.52% Issuance date August 2005 July 2006 August 2006 Distribution dates (1) Quarterly Quarterly Quarterly MB Financial Capital Trust V MB Financial Capital Trust VI Junior Subordinated Notes: Principal balance $ 30,928 $ 23,196 Annual interest rate 3-mo LIBOR + 1.30% 3-mo LIBOR + 1.30% Stated maturity date December 15, 2037 October 30, 2037 Call date December 15, 2012 October 30, 2012 Trust Preferred Securities: Face Value $ 30,000 $ 22,500 Annual distribution rate 3-mo LIBOR + 1.30% 3-mo LIBOR + 1.30% Issuance date September 2007 October 2007 Distribution dates (1) Quarterly Quarterly (1) All distributions are cumulative and paid in cash. The trust preferred securities are subject to mandatory redemption, in whole or in part, upon repayment of the junior subordinated notes at the stated maturity date or upon redemption. Each trust’s ability to pay amounts due on the trust preferred securities is solely dependent upon the Company making payment on the related junior subordinated notes. The Company’s obligation under the junior subordinated notes and other relevant trust agreements, in aggregate, constitute a full and unconditional guarantee by the Company of each trust’s obligations under the trust preferred securities issued by each trust. The Company has the right to defer payment of interest on the notes and, therefore, distributions on the trust preferred securities, for up to five years, but not beyond the stated maturity date in the table above. During any such deferral period, the Company may not pay cash dividends on its common or preferred stock and generally may not repurchase its common or preferred stock. On March 19, 2018, the Company redeemed the junior subordinated notes held by American Chartered Statutory Trust I and, as a result, all of the issued and outstanding three month LIBOR + 3.60% American Chartered Statutory Trust I capital (preferred) securities were concurrently redeemed. The aggregate liquidation amount of these trust preferred securities was $20.0 million . American Chartered Statutory Trust I was established by American Chartered prior to the Company's acquisition of American Chartered, and the junior subordinated notes issued by American Chartered to American Chartered Statutory Trust I were assumed by the Company upon completion of the acquisition. As a result, the Company recognized a $3.1 million loss on extinguishment of debt in the first quarter of 2018. On August 6, 2018, the Company redeemed the junior subordinated notes held by Coal City Capital Trust I and, as a result, all of the issued and outstanding three month LIBOR + 1.80% Coal City Capital Trust I capital (preferred) securities were concurrently redeemed. The aggregate liquidation amount of these trust preferred securities was $25.0 million . Coal City Capital Trust I was established by Coal City Corporation, a predecessor to the Company, and the junior subordinated notes issued by Coal City Corporation to Coal City Capital Trust I were assumed by the Company. As a result, the Company recognized a $341 thousand loss on extinguishment of debt in the third quarter of 2018. On September 17, 2018, the Company redeemed the junior subordinated notes held by TAYC Capital Trust II and, as a result, all of the issued and outstanding three month LIBOR + 2.68% TAYC Capital Trust II capital (preferred) securities were concurrently redeemed. The aggregate liquidation amount of these trust preferred securities was $40.0 million . TAYC Capital Trust II was established by Taylor Capital Group, Inc. ("Taylor Capital") prior to the Company's acquisition of Taylor Capital and the junior subordinated notes issued by Taylor Capital to TAYC Capital Trust II were assumed by the Company upon completion of the acquisition. As a result, the Company recognized a $5.9 million loss on extinguishment of debt in the third quarter of 2018. On October 7, 2018, the Company redeemed the junior subordinated notes held by American Chartered Statutory Trust II and, as a result, all of the issued and outstanding three month LIBOR + 2.75% American Chartered Statutory Trust II capital (preferred) securities were concurrently redeemed. The aggregate liquidation amount of these trust preferred securities was $10.0 million . American Chartered Statutory Trust II was established by American Chartered prior to the Company's acquisition of American Chartered, and the junior subordinated notes issued by American Chartered to American Chartered Statutory Trust II were assumed by the Company upon completion of the acquisition. As a result, the Company recognized a $2.5 million loss on extinguishment of debt in the fourth quarter of 2018. On October 23, 2018, the Company redeemed the junior subordinated notes held by FOBB Statutory Trust III and, as a result, all of the issued and outstanding three month LIBOR + 2.80% FOBB Statutory Trust III capital (preferred) securities were concurrently redeemed. The aggregate liquidation amount of these trust preferred securities was $5.0 million . FOBB Statutory Trust III was established by First Oak Brook Bancshares, Inc. ("First Oak Brook") prior to the Company's acquisition of First Oak Brook, and the junior subordinated notes issued by First Oak Brook to FOBB Statutory Trust III were assumed by the Company upon completion of the acquisition.

Lease Commitments and Rental Ex

Lease Commitments and Rental Expense	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Lease Commitments and Rental Expense	Lease Commitments and Rental Expense The Company leases office space for certain branch and non-bank offices. At December 31, 2018 , the future minimum annual rental commitments for these non-cancelable leases and subleases of such space were as follows (in thousands): Gross Sublease Net Years ending December 31, Rents Rents Rents 2019 $ 11,902 $ 1,276 $ 10,626 2020 8,272 532 7,740 2021 6,988 195 6,793 2022 5,452 16 5,436 2023 4,308 — 4,308 Thereafter 17,248 — 17,248 $ 54,170 $ 2,019 $ 52,151 Under the terms of these leases, the Company is required to pay its pro rata share of the cost of maintenance and real estate taxes. Certain leases also provide for increased rental payments based on increases in the Consumer Price Index. Net rental expense for the years ended December 31, 2018 , 2017 , and 2016 amounted to $11.8 million , $11.3 million , and $10.9 million , respectively.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company has a defined contribution 401(k) profit sharing plan that covers most full-time employees who have completed three months of service. Each participant under the plan may contribute up to 75% of his/her eligible compensation on a pretax basis. The Company’s contributions consist of a discretionary profit-sharing contribution and a matching contribution of the amounts contributed by the participants. The board of directors determines the Company’s contributions on an annual basis. During 2018 , each participant was eligible for a maximum total Company matching contribution of 3.5% of their eligible compensation. Additionally, the Company may make annual discretionary profit sharing contributions. The Company’s total contribution to the plan for the year ended December 31, 2018 was $16.7 million and was $17.2 million and $14.8 million for the years ended December 31, 2017 and 2016 , respectively. The Company has deferred compensation plans that allow certain executives, senior officers, directors and other employees to defer payment of up 100% of their base salary and bonus in the case of employees and board fees in the case of directors. Company contributions to these plans, which include discretionary contributions and the annual contribution to the Chief Executive Officer's account described below, were $1.5 million for the year ended December 31, 2018 . These contributions were $869 thousand and $806 thousand for the years ended December 31, 2017 and 2016 , respectively. Pursuant to the employment agreement between the Company and its Chief Executive Officer, he is entitled to receive on each December 31st while he is employed by the Company (starting December 31, 2007) a fully vested employer contribution to his account under the Company's non-stock deferred compensation plan in amount equal to 20% of his base salary then in effect. The amounts deferred can be invested in MB Financial stock (under the Company’s stock deferred compensation plan) or publicly traded mutual funds (under the Company’s non-stock deferred compensation plan) at the discretion of the participant. The cost of the MB Financial common stock held by MB Financial’s deferred compensation plans is reported separately in a manner similar to treasury stock (that is, changes in fair value are not recognized) with a corresponding deferred compensation obligation reflected in additional paid-in capital. The amounts of the assets that are not invested in MB Financial common stock are recorded at their fair market value in other assets on the consolidated balance sheet. As of December 31, 2018 , the fair value of the assets held in other publicly traded funds totaled $27.9 million . A liability is established, in other liabilities, on the consolidated balance sheet, for the fair value of the obligation to the participants. Any increase or decrease in the fair market value of plan assets is recorded in other non-interest income on the consolidated statement of operations. Any increase or decrease in the fair value of the deferred compensation obligation to participants is recorded as additional compensation expense or a reduction of compensation expense on the consolidated statement of operations. The decrease in fair market value of the assets and the obligation related to the deferred compensation plan was $1.4 million for the year ended December 31, 2018 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The deferred taxes consist of (in thousands): December 31, 2018 2017 Deferred tax asset: Allowance for credit losses $ 42,208 $ 42,560 State net operating loss carryforwards 19,495 26,981 Other real estate owned 2,182 1,905 Stock options and restricted stock 5,875 5,929 Loans 7,766 12,762 Deferred compensation 7,812 6,918 Tax credit carryforwards 13,525 40,197 Bonus accrual 8,620 2,172 Other items 311 1,797 Total deferred tax asset 107,794 141,221 Valuation allowance — — Total deferred tax asset, net of valuation allowance 107,794 141,221 Deferred tax liability: Equipment leasing (121,142 ) (127,465 ) Premises and equipment (20,856 ) (17,250 ) Mortgage servicing rights (66,749 ) (62,091 ) Deferred income from FDIC-assisted transactions (12,583 ) (20,895 ) Deferred loan costs (10,604 ) (7,555 ) Investment securities (6,876 ) (5,933 ) FHLB stock dividends (2,141 ) (2,195 ) Core deposit intangible (7,239 ) (9,023 ) Other items (4,794 ) (3,683 ) Total deferred tax liability (252,984 ) (256,090 ) Net deferred tax liability (145,190 ) (114,869 ) Net unrealized holding gain on investment securities available for sale 1,842 (959 ) Net deferred tax liability $ (143,348 ) $ (115,828 ) The Company’s Illinois net operating loss carryforwards totaled $258.7 million at December 31, 2018 and begin to expire in 2023 through 2028. The Company's tax credit carryforwards include federal alternative minimum tax credits of $13.5 million with no expiration. Management has determined that is more likely than not that the deferred tax assets, including the net operating loss carryforwards, as of December 31, 2018 , will be realized and that no valuation allowance is required. The Company also had other state net operating loss carryforwards totaling $1.3 million at December 31, 2018 , which do not begin to expire until after 2028. On December 22, 2017, H.R.1, originally known as the “Tax Cuts and Jobs Act” (the "Tax Reform Legislation") was enacted into law. This new tax legislation, among other changes, reduced the Federal corporate income tax rate from 35% to 21% effective January 1, 2018. As required under ASC Topic 740 "Income Taxes," the Company re-measured its deferred tax assets and liabilities at December 31, 2017 for the Tax Reform Legislation, which resulted in a tax benefit of $104.2 million in the year ended December 31, 2017 and re-measurement adjustments of $13.7 million in the year ended December 31, 2018. This re-measurement as of December 31, 2018 was determined to be final. Income taxes attributable to continuing operations consist of (in thousands): Years Ended December 31, 2018 2017 2016 Current expense (benefit): Federal $ (4,850 ) $ 12,346 $ 26,081 State 12,290 6,994 7,204 Foreign 495 157 42 7,935 19,497 33,327 Deferred expense (benefit): Federal 31,244 (45,401 ) 37,690 State (923 ) 10,679 8,227 Foreign — — — 30,321 (34,722 ) 45,917 Income tax expense (benefit) $ 38,256 $ (15,225 ) $ 79,244 The reconciliation between the statutory federal income tax rate of 21% for 2018 and 35% for 2017 and 2016 and the effective tax rate on income from continuing operations follows (in thousands): Years Ended December 31, 2018 2017 2016 Federal income tax expense at expected statutory rate $ 52,956 $ 101,085 $ 88,683 (Decrease) increase due to: Tax exempt income, net (9,708 ) (17,164 ) (18,214 ) Tax benefit resulting from change in tax rates (13,741 ) (106,563 ) — State tax expense net of federal impact 8,980 11,487 10,030 Stock-based compensation excess tax benefits (1,597 ) (3,195 ) (2,330 ) Non-deductible contingent consideration 406 138 1,026 Non-includable increase in cash surrender value of life insurance (1,046 ) (1,889 ) (1,432 ) Non-deductible merger expense 878 — 298 Adjustment of unrecognized tax benefit (8 ) 94 1 Other items, net 1,136 782 1,182 Income tax expense $ 38,256 $ (15,225 ) $ 79,244 ASC Topic 740, "Accounting for Uncertainty in Income Taxes" provides guidance on financial statement recognition and measurement of tax positions taken, or expected to be taken, in tax returns. A reconciliation of the change in unrecognized tax benefits from January 1, 2018 to December 31, 2018 is as follows (in thousands): Unrecognized Tax Benefit Without Interest Interest on unrecognized Tax Benefit Total Unrecognized Tax Benefit Including Interest Balance at January 1, 2018 $ 113 $ — $ 113 Decreases related to prior year tax positions (8 ) — (8 ) Balance at December 31, 2018 $ 105 $ — $ 105 The whole amount of unrecognized tax benefits would affect the tax provision and the effective income tax rate if recognized in future periods. The Company elects to treat interest and penalties recognized for the underpayment of income taxes as income tax expense, to the extent not included in unrecognized tax benefits. The Company’s federal income tax returns are open and subject to examination for the 2015 tax return year and forward. The Company’s various state income tax returns are generally open for the 2014 tax return year and forward based on individual state statutes of limitation. The Company is currently under examination by federal and state taxing authorities.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments: The Company is a party to credit-related financial instruments with off-balance-sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit, standby letters of credit and commercial letters of credit. Such commitments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheets. The Company’s exposure to credit loss is represented by the contractual amount of these commitments. The Company follows the same credit policies in making commitments as it does for on-balance-sheet instruments. At December 31, 2018 and 2017 , the following financial instruments were outstanding, the contractual amounts of which represent off-balance sheet credit risk (in thousands): Contractual Amount 2018 2017 Commitments to extend credit: Home equity lines $ 179,521 $ 203,922 Other commitments 4,058,853 4,073,044 Letters of credit: Standby 173,755 161,014 Commercial 5,657 2,248 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require a payment of a fee. The commitments for home equity lines of credit may expire without being drawn upon. Therefore, the total commitment amounts do not necessarily represent future cash requirements. The amount of collateral obtained, if it is deemed necessary by the Company, is based on management’s credit evaluation of the customer. The Company, in the normal course of its business, regularly offers standby and commercial letters of credit to its bank customers. Standby and commercial letters of credit are a conditional but irrevocable form of guarantee. Under letters of credit, the Company typically guarantees payment to a third party beneficiary upon the default of payment or nonperformance by the bank customer and upon receipt of complying documentation from that beneficiary. Both standby and commercial letters of credit may be issued for any length of time, but normally do not exceed a period of five years. These letters of credit may also be extended or amended from time to time depending on the bank customer’s needs. As of December 31, 2018 , the maximum remaining term for any standby letters of credit matures on December 31, 2025 . A fee is charged to the bank customer and is recognized as income over the life of the letter of credit, unless considered non-rebatable under the terms of a letter of credit application. At December 31, 2018 , the aggregate contractual amount of these letters of credit, which represents the maximum potential amount of future payments that the Company would be obligated to pay, increased $16.2 million to $179.4 million from $163.3 million at December 31, 2017 . Of the $179.4 million in commitments outstanding at December 31, 2018 , approximately $158.2 million of the letters of credit have been issued or renewed since December 31, 2017 . Letters of credit issued on behalf of bank customers may be done on either a secured, partially secured or an unsecured basis. If a letter credit is secured or partially secured, the collateral can take various forms including bank accounts, investments, fixed assets, inventory, accounts receivable or real estate. The Company takes the same care in making credit decisions and obtaining collateral when it issues letters of credit on behalf of its customers as it does when making other types of loans. Concentrations of credit risk: The majority of the loans, commitments to extend credit and standby letters of credit have been granted to customers in the Company’s market area. As of December 31, 2018 , approximately 20% of our investments in securities issued by states and political subdivisions were within the State of Illinois. We did not hold any direct exposure to the State of Illinois as of December 31, 2018 . The distribution of commitments to extend credit approximates the distribution of loans outstanding. Standby letters of credit are granted primarily to commercial borrowers. Our asset-based loans are made to borrowers located throughout the United States. Lease banking provides banking services to lessors located throughout the United States. Our leasing subsidiaries originate leases to companies located through the United States. Contingencies: In the normal course of business, the Company is involved in various legal proceedings. In the opinion of management, any liability resulting from pending proceedings would not be expected to have a material adverse effect on the Company’s consolidated financial statements.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Regulatory Matters	Regulatory Matters The Company’s primary source of cash is dividends from its bank subsidiary, MB Financial Bank. The bank subsidiary is subject to certain restrictions on the amount of dividends that it may declare without prior regulatory approval. In addition, the dividends declared cannot be in excess of the amount which would cause the bank subsidiary to fall below the minimum required for capital adequacy purposes. The Company and its bank subsidiary are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory — and additional discretionary — actions by regulators that, if undertaken, could have a direct material effect on the Company’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company’s and its bank subsidiary’s assets, liabilities, and certain off-balance-sheet items are calculated under regulatory accounting practices. The Company’s and its bank subsidiary’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Prompt corrective action provisions are not applicable to bank holding companies. Quantitative measures established by regulation to ensure capital adequacy require the Company and its bank subsidiary to maintain minimum amounts and ratios (set forth in the table below) of total and Tier 1 capital (as defined in the regulations) to risk-weighted assets (as defined), and of Tier 1 capital (as defined) to average assets (as defined). Management believes the Company and its bank subsidiary met all capital adequacy requirements to which they were subject as of December 31, 2018 and 2017 . As of December 31, 2018 , the most recent regulatory notification categorized the bank subsidiary as “well capitalized” under the regulatory framework then in effect for prompt corrective action. To be categorized as “well capitalized” as of December 31, 2018 , the bank subsidiary must have maintained the total risk-based, Tier 1 risk-based, common equity Tier 1 and Tier 1 leverage ratios as set forth in the well-capitalized column in the table below. There are no conditions or events since that notification that management believes have changed the bank subsidiary’s categories. The required and actual amounts and ratios for the Company and its bank subsidiary are presented below as of the dates indicated (dollars in thousands): To Be Well Capitalized Under For Capital Prompt Corrective Actual Adequacy Purposes Action Provisions Amount Ratio Amount Ratio Amount Ratio As of December 31, 2018 Total capital (to risk-weighted assets): Consolidated $ 2,379,813 13.67 % $ 1,392,791 8.00 % N/A N/A MB Financial Bank 2,264,296 13.05 1,388,457 8.00 $ 1,735,571 10.00 % Tier 1 capital (to risk-weighted assets): Consolidated $ 1,959,413 11.25 % 1,044,593 6.00 % N/A N/A MB Financial Bank 1,927,240 11.10 1,041,343 6.00 1,388,457 8.00 % Common equity tier 1 capital (to risk-weighted assets): Consolidated $ 1,764,694 10.14 % 783,445 4.50 % N/A N/A MB Financial Bank 1,925,076 11.09 781,007 4.50 1,128,121 6.50 % Tier 1 capital (to average assets): Consolidated $ 1,959,413 10.50 % 746,268 4.00 % N/A N/A MB Financial Bank 1,927,240 10.35 744,676 4.00 930,845 5.00 % As of December 31, 2017 Total capital (to risk-weighted assets): Consolidated $ 2,428,301 14.23 % $ 1,364,733 8.00 % N/A N/A MB Financial Bank 2,217,547 13.03 1,361,855 8.00 $ 1,702,318 10.00 % Tier 1 capital (to risk-weighted assets): Consolidated 1,910,336 11.20 % 1,023,550 6.00 % N/A N/A MB Financial Bank 1,883,140 11.06 1,021,391 6.00 1,361,855 8.00 % Common equity tier 1 capital (to risk-weighted assets): Consolidated 1,603,479 9.40 % 767,662 4.50 % N/A N/A MB Financial Bank 1,883,140 11.06 766,043 4.50 1,106,507 6.50 % Tier 1 capital (to average assets): Consolidated 1,910,336 10.02 % 762,370 4.00 % N/A N/A MB Financial Bank 1,883,140 9.90 760,797 4.00 950,996 5.00 % N/A — not applicable The Company and the Bank must maintain a capital conservation buffer consisting of additional common equity tier 1 capital greater than 2.5% of risk-weighted assets above the required minimum risk-based capital levels in order to avoid limitations on paying dividends, repurchasing shares, and paying discretionary bonuses. The capital conservation buffer requirement began to be phased in on January 1, 2016 when a buffer greater than 0.625% of risk-weighted assets was required, which amount increased each year until the buffer requirement became fully implemented on January 1, 2019. The conservation buffers for the Company and the Bank exceed the fully phased in minimum as of December 31, 2018 .

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements ASC Topic 820 defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. A fair value measurement assumes that the transaction to sell the asset or transfer the liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability. The price in the principal (or most advantageous) market used to measure the fair value of the asset or liability shall not be adjusted for transaction costs. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets and liabilities; it is not a forced transaction. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact and (iv) willing to transact. ASC Topic 820 requires the use of valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities. The income approach uses valuation techniques to convert expected future amounts, such as cash flows or earnings, to a single present value amount on a discounted basis. The cost approach is based on the amount that currently would be required to replace the service capacity of an asset (replacement cost). Valuation techniques should be consistently applied. Inputs to valuation techniques refer to the assumptions that market participants would use in pricing the asset or liability. Inputs may be observable, meaning those that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from independent sources, or unobservable, meaning those that reflect the reporting entity's own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. In that regard, ASC Topic 820 establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: Level 1: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the entity has the ability to access as of the measurement date. Level 2: Significant other observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. Level 3: Significant unobservable inputs that reflect a reporting entity's own assumptions about the assumptions that market participants would use in pricing an asset or liability. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. These adjustments may include amounts to reflect counterparty credit quality, the Company's creditworthiness, among other things, as well as unobservable parameters. Any such valuation adjustments are applied consistently over time. Our valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes the Company's valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstances that caused the transfer, which generally coincides with the Company's monthly and/or quarterly valuation process. Financial Instruments Recorded at Fair Value on a Recurring Basis Securities Available for Sale . The fair values of securities available for sale are determined by quoted prices in active markets, when available, and classified as Level 1. If quoted market prices are not available, the fair value is determined by matrix pricing, which is a mathematical technique widely used in the industry to value debt securities without relying exclusively on quoted prices for the specific securities but rather by relying on the securities' relationship to other benchmark quoted securities and classified as Level 2. In cases where significant credit valuation adjustments are incorporated into the estimation of fair value, reported amounts are classified as Level 3. The change in fair value is recorded through an adjustment to the statement of other comprehensive income. Marketable Equity Securities . The fair values of marketable equity securities are determined by quoted prices in active markets, when available, and classified as Level 1. The change in fair value is recorded through an adjustment to the statement of operations. Loans Held for Sale. Mortgage loans originated and held for sale in the secondary market are carried at fair value. The fair value of loans held for sale is determined using quoted secondary market prices and classified as Level 2. The change in fair value is recorded through an adjustment to the statement of operations. Loans. The Company has elected to record certain mortgage loans at fair value. The fair value of these loans is determined using quoted secondary market prices and classified as Level 2. The change in fair value is recorded through an adjustment to the statement of operations. Mortgage Servicing Rights. The Company has elected to record its mortgage servicing rights at fair value. Mortgage servicing rights do not trade in an active market with readily observable prices. Accordingly, the Company determines the fair value of mortgage servicing rights by estimating the fair value of the future cash flows associated with the mortgage loans being serviced. Key economic assumptions used in measuring the fair value of mortgage servicing rights include, but are not limited to, prepayment speeds, discount rates, delinquencies and cost to service. The assumptions used in the model are validated on a regular basis. The fair value is validated on a quarterly basis with an independent third party. Any material discrepancies between the internal model and the third party validation are investigated and resolved by an internal committee. Due to the nature of the valuation inputs, mortgage servicing rights are classified in Level 3 of the fair value hierarchy. The change in fair value is recorded through an adjustment to the statement of operations. Assets Held in Trust for Deferred Compensation and Associated Liabilities. Assets held in trust for deferred compensation are recorded at fair value and included in “Other Assets” on the consolidated balance sheets. These assets are invested in mutual funds and classified as Level 1. Deferred compensation liabilities, also classified as Level 1, are carried at the fair value of the obligation to the employee, which corresponds to the fair value of the invested assets. The change in fair value is recorded through an adjustment to the statement of operations. Derivatives . Currently, we use interest rate swaps to manage our interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative and classified as Level 2. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including LIBOR rate curves. The Company also obtains dealer quotations for these derivatives for comparative purposes to assess the reasonableness of the model valuations. In addition, the Company uses treasury futures and forward commitments to buy to-be-announced ("TBA") mortgage securities to lessen the price volatility of the mortgage servicing rights asset. The Company does not intend to take delivery of these mortgage securities; it will sell the position before taking physical delivery. Dealer quotations are used for the treasury futures and TBA mortgage securities derivatives and are classified as Level 1. The Company also offers other derivatives, including foreign currency forward contracts and interest rate lock commitments, to our customers and offset our exposure from such contracts by purchasing other financial contracts, which are valued using market consensus prices. For certain interest rate lock commitments, the Company uses an external valuation model that relies on internally developed inputs to estimate the fair value of its interest rate lock commitments. This is based on unobservable inputs that reflect management’s assumptions and specific information about each borrower transaction and is classified in Level 3 of the hierarchy. The change in fair value is recorded through an adjustment to the statement of operations. The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2018 and 2017 , segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) 2018 Financial assets Securities available for sale: U.S. Treasury securities $ 75,141 $ 75,141 $ — $ — U.S. Government sponsored agencies and enterprises 5,024 — 5,024 — States and political subdivisions 341,477 — 341,195 282 Residential mortgage-backed securities 1,402,453 — 1,402,453 — Commercial mortgage-backed securities 31,587 — 31,587 — Corporate bonds — — — — Marketable equity securities 11,075 11,075 — — Loans held for sale 45,550 — 45,550 — Loans 42,665 — 42,665 — Mortgage servicing rights 284,898 — — 284,898 Assets held in trust for deferred compensation 27,882 27,882 — — Derivative financial instruments 45,168 1,534 43,526 108 Financial liabilities Other liabilities (1) 27,882 27,882 — — Derivative financial instruments 41,300 215 41,085 — 2017 Financial assets Securities available for sale: U.S. Government sponsored agencies and enterprises $ 23,007 $ — $ 23,007 $ — States and political subdivisions 379,325 — 378,996 329 Residential mortgage-backed securities 852,699 — 852,665 34 Commercial mortgage-backed securities 72,035 — 72,035 — Corporate bonds 70,197 — 70,197 — Equity securities 11,063 11,063 — — Loans held for sale 548,578 — 548,578 — Loans 40,531 — 40,531 — Mortgage servicing rights 276,279 — — 276,279 Assets held in trust for deferred compensation 21,410 21,410 — — Derivative financial instruments 31,499 389 29,539 1,571 Financial liabilities Other liabilities (1) 21,410 21,410 — — Derivative financial instruments 40,296 1,072 39,224 — (1) Liabilities associated with assets held in trust for deferred compensation The following tables present additional information about the unobservable inputs used in the fair value measurement of financial assets measured on a recurring basis that were categorized within the Level 3 of the fair value hierarchy (fair value in thousands): Fair Value at December 31, 2018 Valuation Technique Unobservable Input Range (in thousands) States and political subdivisions $ 282 Discounted cash flows Credit assumption 35-40% Loss Mortgage servicing rights 284,898 Discounted cash flows CPR 6.5% - 7.3% Discount rate 9.53 - 11.08 Maturity (months) 328 - 358 Delinquencies 1.92 - 4.36 Costs to service $ 67 - $ 227 Additive delinquent costs to service $ 175 - $ 1,000 Derivative financial instruments (mortgage 108 Sales cash flows Expected closing ratio 70% - 95% interest rate lock commitments) Expected delivery price 99.48 bps - 105.31 bps Fair Value at December 31, 2017 Valuation Technique Unobservable Input Range (in thousands) States and political subdivisions $ 329 Discounted cash flows Credit assumption 40-45% Loss Residential mortgage-backed securities 34 Discounted cash flows Constant pre-payment rates (CPR) 1% - 3% Mortgage servicing rights 276,279 Discounted cash flows CPR 6.7% - 7.8% Discount rate 9.53 - 11.06 Maturity (months) 324 - 358 Delinquencies 2.42 - 5.30 Costs to service $ 67 - $ 227 Additive delinquent costs to service $ 175 - $ 1,000 Derivative financial instruments (mortgage 1,571 Sales cash flows Expected closing ratio 70% - 95% interest rate lock commitments) Expected delivery price 97.38 bps - 106.87 bps The significant unobservable inputs used in the fair value measurement of the Company’s mortgage servicing rights include prepayment speeds, discount rates, maturities, delinquencies and cost to service. Significant increases in prepayment speeds, discount rates, delinquencies or cost to service would result in a significantly lower fair value measurement. Conversely, significant decreases in prepayment speeds, discount rates, delinquencies or costs to service would result in a significantly higher fair value measurement. With the exception of changes in delinquencies, which can change the cost to service, the unobservable inputs move independently of each other. Key economic assumptions used in the measuring of the fair value of the mortgage servicing rights and the sensitivity of the fair value to immediate adverse changes in those assumptions at December 31, 2018 are presented in the following table. This table does not take into account the derivatives used to economically hedge the mortgage servicing rights. (dollars in thousands, except for weighted average cost to service) December 31, 2018 Weighted average prepayment speed (CPR) 6.76 % Impact on fair value of 10% adverse change $ (8,462 ) Impact on fair value of 20% adverse change (16,499 ) Weighted average discount rate 9.84 % Impact on fair value of 10% adverse change $ (12,045 ) Impact on fair value of 20% adverse change (23,128 ) Weighted average delinquency rate 4.08 % Impact on fair value of 10% adverse change $ (2,591 ) Impact on fair value of 20% adverse change (4,558 ) Weighted average costs to service $ 90 Impact on fair value of 10% adverse change (5,177 ) Impact on fair value of 20% adverse change (10,355 ) The Company did not have any transfers between Level 1 and Level 2 of the fair value hierarchy during the year ended December 31, 2018 . The Company's policy for determining transfers between levels occurs at the end of the reporting period when circumstances in the underlying valuation criteria change and result in transfer between levels. The following table presents additional information about financial assets measured at fair value on a recurring basis for which the Company used significant unobservable inputs (Level 3) (in thousands): Year Ended December 31, 2018 2017 2018 2017 2018 2017 Investment Securities Mortgage Servicing Rights Derivatives Balance, beginning of period $ 363 $ 544 $ 276,279 $ 238,011 $ 1,571 $ 3,160 Purchases — — 161 865 — — Originations — — 30,843 59,810 — — Included in earnings (12 ) — (22,385 ) (22,407 ) (1,463 ) (1,589 ) Principal payments (69 ) (181 ) — — — — Balance, ending of period $ 282 $ 363 $ 284,898 $ 276,279 $ 108 $ 1,571 Financial Instruments Recorded at Fair Value on a Nonrecurring Basis The Company may be required, from time to time, to measure certain financial assets and financial liabilities at fair value on a nonrecurring basis in accordance with U.S. GAAP. These include assets that are measured at the lower of cost or fair value that were recognized at fair value below cost at the end of the period. Impaired Loans. Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired. Once a loan is identified as individually impaired, management measures impairment in accordance with ASC Topic 310. The fair value of impaired loans is estimated using one of several methods, including collateral value, market value of similar debt, enterprise value, liquidation value, and discounted cash flows. Those impaired loans not requiring an allowance represent loans for which the fair value of the expected repayments or collateral exceed the recorded investments in such loans. In accordance with ASC Topic 820, impaired loans where an allowance is established based on the fair value of collateral require classification in the fair value hierarchy. Collateral values are estimated using Level 3 inputs based on customized discounting criteria. For a majority of impaired real estate loans where an allowance is established based on the fair value of collateral ( 100% at December 31, 2018 ), the Company obtains a current external appraisal. Other valuation techniques are used as well, including internal valuations, comparable property analysis and contractual sales information. Non-Financial Assets and Non-Financial Liabilities Recorded at Fair Value The Company has no non-financial assets or non-financial liabilities measured at fair value on a recurring basis. Certain non-financial assets and non-financial liabilities measured at fair value on a non-recurring basis include foreclosed assets and non-financial long-lived assets. Other Real Estate and Repossessed Vehicles Owned (Foreclosed Assets). Foreclosed assets, upon initial recognition, are measured and reported at fair value through a charge-off to the allowance for loan and lease losses based upon the fair value of the foreclosed asset. The fair value of foreclosed assets, upon initial recognition, are estimated using Level 3 inputs based on customized discounting criteria. Non-Financial Long-Lived Assets. Non-financial long-lived assets, when determined to be impaired, are measured and reported at fair value using Level 3 inputs based on customized discounting criteria. Assets measured at fair value on a nonrecurring basis as of December 31, 2018 and 2017 are included in the table below (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) 2018 Financial assets: Impaired loans $ 61,005 $ — $ — $ 61,005 Non-financial assets: Foreclosed assets 11,354 — — 11,354 2017 Financial assets: Impaired loans $ 60,569 $ — $ — $ 60,569 Non-financial assets: Foreclosed assets 15,113 — — 15,113 The following tables present additional information about the unobservable inputs used in the fair value measurement of financial and non-financial assets measured on a nonrecurring basis that were categorized within the Level 3 of the fair value hierarchy (fair value in thousands): Fair Value at Valuation December 31, 2018 Technique Unobservable Input Range Impaired loans $ 61,005 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% Foreclosed assets 11,354 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% Fair Value at Valuation December 31, 2017 Technique Unobservable Input Range Impaired loans $ 60,569 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% Foreclosed assets 15,113 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% ASC Topic 825 requires disclosure of the fair value of financial assets and financial liabilities, including those financial assets and financial liabilities that are not measured and reported at fair value on a recurring basis or non-recurring basis. The methodologies for estimating the fair value of financial assets and financial liabilities that are measured at fair value on a recurring or non-recurring basis are discussed above. The estimated fair value approximates carrying value for cash and cash equivalents, accrued interest and the cash surrender value of life insurance policies. The methodologies for other financial assets and financial liabilities are discussed below: The following methods and assumptions were used by the Company in estimating the fair values of its other financial instruments: Cash and due from banks and interest earning deposits with banks: The carrying amounts reported in the balance sheet approximate fair value. Securities held to maturity: The fair values of securities held to maturity are determined by quoted prices in active markets, when available, and classified as Level 1. If quoted market prices are not available, the fair value is determined by matrix pricing, which is a mathematical technique widely used in the industry to value debt securities without relying exclusively on quoted prices for the specific securities but rather by relying on the securities' relationship to other benchmark quoted securities and classified as Level 2. In cases where significant credit valuation adjustments are incorporated into the estimation of fair value, reported amounts are classified as Level 3. Non-marketable securities - FHLB and FRB Stock: The carrying amounts reported in the balance sheet approximate fair value. Loans : The fair values for loans are estimated using discounted cash flow analyses, using the corporate bond curve adjusted for liquidity for commercial loans and the swap curve adjusted for liquidity for retail loans, including increased interest rate spreads to incorporate a credit mark, estimating an exit price. Non-interest bearing deposits : The fair values disclosed are equal to their balance sheet carrying amounts, which represent the amount payable on demand. Interest bearing deposits : The fair values disclosed for deposits with no defined maturities are equal to their carrying amounts, which represent the amounts payable on demand. Fair values for certificates of deposit are estimated using a discounted cash flow calculation that applies the Company's current incremental borrowing rates for similar terms. Short-term borrowings : The carrying amounts of federal funds purchased, borrowings under repurchase agreements and other short-term borrowings with maturities of 90 days or less approximate their fair values. The fair value of short-term borrowings greater than 90 days is based on the discounted value of contractual cash flows. Long-term borrowings : The fair values of the Company's long-term borrowings (other than deposits) are estimated using discounted cash flow analyses, based on the Company's current incremental borrowing rates for similar types of borrowing arrangements. Junior subordinated notes issued to capital trusts : The fair values of the Company's junior subordinated notes issued to capital trusts are estimated based on the quoted market prices, when available, of the related trust preferred security instruments, or are estimated based on the quoted market prices of comparable trust preferred securities. Accrued interest : The carrying amount of accrued interest receivable and payable approximate their fair values. Off-balance-sheet instruments : Fair values for the Company’s off-balance-sheet lending commitments (guarantees, letters of credit and commitments to extend credit) are based on fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements. The estimated fair values of financial instruments are as follows (in thousands): December 31, 2018 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash and due from banks $ 503,153 $ 503,153 $ 503,153 $ — $ — Interest bearing deposits with banks 147,254 147,254 147,254 — — Investment securities available for sale 1,855,682 1,855,682 75,141 1,780,259 282 Investment securities held to maturity 901,684 919,660 — 919,660 — Marketable equity securities 11,075 11,075 11,075 — — Non-marketable securities - FHLB and FRB stock 113,957 113,957 — — 113,957 Loans held for sale 45,550 45,550 — 45,550 — Loans, net 13,873,605 13,937,096 — 42,665 13,894,431 Accrued interest receivable 68,801 68,801 68,801 — — Derivative financial instruments 45,168 45,168 1,534 43,526 108 Financial Liabilities: Non-interest bearing deposits $ 6,152,163 $ 6,152,163 $ 6,152,163 $ — $ — Interest bearing deposits 8,502,050 8,492,037 — — 8,492,037 Short-term borrowings 1,470,055 1,470,190 — — 1,470,190 Long-term borrowings 349,681 351,141 — — 351,141 Junior subordinated notes issued to capital trusts 121,118 89,321 — — 89,321 Accrued interest payable 7,216 7,216 7,216 — — Derivative financial instruments 41,300 41,300 215 41,085 — December 31, 2017 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash and due from banks $ 397,880 $ 397,880 $ 397,880 $ — $ — Interest bearing deposits with banks 181,341 181,341 181,341 — — Investment securities available for sale 1,408,326 1,408,326 11,063 1,396,900 363 Investment securities held to maturity 959,082 992,455 — 992,455 — Non-marketable securities - FHLB and FRB stock 114,111 114,111 — — 114,111 Loans held for sale 548,578 548,578 — 548,578 — Loans, net 13,808,352 13,988,392 — 40,531 13,947,861 Accrued interest receivable 63,589 63,589 63,589 — — Derivative financial instruments 31,499 31,499 389 29,539 1,571 Financial Liabilities: Non-interest bearing deposits $ 6,381,512 $ 6,381,512 $ 6,381,512 $ — $ — Interest bearing deposits 8,576,866 8,569,368 — — 8,569,368 Short-term borrowings 861,039 860,676 — — 860,676 Long-term borrowings 505,158 513,725 — — 513,725 Junior subordinated notes issued to capital trusts 211,494 170,965 — — 170,965 Accrued interest payable 6,458 6,458 6,458 — — Derivative financial instruments 40,296 40,296 1,072 39,224 —

Stock Incentive Plans

Stock Incentive Plans	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Incentive Plans	Stock Incentive Plans ASC Topic 718 requires that the grant date fair value of equity awards to employees be recognized as compensation expense over the period during which an employee is required to provide service in exchange for such award. The following table summarizes the impact of the Company’s share-based payment plans in the financial statements for the periods shown (in thousands): Year Ended December 31, 2018 2017 2016 Total compensation expense for share-based payment plans during the year $ 18,727 $ 17,476 $ 16,868 Amount of related income tax benefit recognized in income (1) 6,897 10,338 8,983 (1) Includes tax benefits recorded for the vesting of restricted shares and exercise of options. The Company adopted the Omnibus Incentive Plan (the “Omnibus Plan”) in 1997. On May 28, 2014, the Company’s stockholders approved the third amendment and restatement of the Omnibus Plan to add 3,100,000 authorized shares for a total of 11,400,000 shares of common stock authorized to be utilized in connection with awards under the Omnibus Plan to directors, officers, and employees of the Company or any of its subsidiaries. The number of shares authorized increased by 2,400,000 to 13,800,000 upon completion of the Taylor Capital merger. Equity grants under the Omnibus Plan can be in the form of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units, performance shares, performance units, and other stock-based awards. Shares awarded in the form of restricted stock, restricted stock units, performance shares, performance units, or other stock-based awards generally will reduce the shares available under the Omnibus Plan on a 2 -for- 1 basis. No more than 10% of the total number of authorized shares may be issued with respect to awards granted after May 28, 2014, other than stock appreciation rights, stock options and performance-based awards, which at the date of grant are scheduled to fully vest prior to three years from the date of grant (although such awards may provide scheduled vesting earlier with respect to some of such shares and for acceleration of vesting as provided in the Omnibus Plan). As of December 31, 2018 , there were 2,138,446 shares available for future grants. Annual equity-based incentive awards are generally granted to selected officers and employees in the first quarter of the year. Options are granted with an exercise price equal to no less than the market price of the Company’s shares at the date of grant; those option awards generally vest over four years of service and have 10 -year contractual terms. Restricted shares and units typically vest over a two to four year period. Equity awards may also be granted at other times throughout the year in connection with the recruitment and retention of officers and employees. Directors currently may elect, in lieu of cash, to receive up to 70% of their fees in stock options with a five year term, which are fully vested on the grant date (provided that the director may not sell the underlying shares for at least six months after the grant date), and up to 100% of their fees in restricted shares, which vest one year after the grant date. The following table summarizes stock options outstanding for the year ended December 31, 2018 : Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Options outstanding as of December 31, 2017 1,721,978 $ 29.10 5.19 Granted 175,501 41.26 Exercised (493,984 ) 26.35 Expired (2,362 ) 32.99 Forfeited or cancelled (28,939 ) 31.63 Options outstanding as of December 31, 2018 1,372,194 $ 31.58 5.71 $ 12,327 Options exercisable as of December 31, 2018 887,401 $ 28.68 4.55 $ 10,137 The fair value of each option award is estimated on the date of grant using the Black-Scholes option pricing model based on certain assumptions. Expected volatility is based on historical volatility and the expectations of future volatility of Company shares. The risk free interest rate for periods within the contractual term of the option is based on the U.S. Treasury yield curve in effect at the time of the grant. The expected life of options is estimated based on historical employee behavior and represents the period of time that options granted are expected to remain outstanding. The following assumptions were used for options granted during the years ended December 31, 2018 , 2017 , and 2016 : For the Years Ended December 31, 2018 2017 2016 Risk-free interest rate 2.79 % 2.18 % 1.44 % Expected volatility of Company’s stock 25.96 % 22.71 % 28.08 % Expected dividend yield 2.08 % 1.68 % 2.19 % Expected life of options (years) 5.5 5.8 5.5 Weighted average fair value per option of options granted during the year $ 9.21 $ 9.35 $ 6.66 The total intrinsic value of options exercised during the years ended December 31, 2018 , 2017 and 2016 was $10.6 million , $6.1 million and $7.0 million , respectively. The following is a summary of changes in restricted shares and units for the year ended December 31, 2018 : Number of Shares Weighted Average Grant Date Fair Value Shares and Units Outstanding at December 31, 2017 973,201 $ 37.03 Granted 428,752 41.65 Vested (371,640 ) 35.17 Forfeited or cancelled (114,146 ) 35.89 Shares and Units Outstanding at December 31, 2018 916,167 40.09 The total intrinsic value of restricted shares that vested during the years ended December 31, 2018 , 2017 and 2016 was $15.5 million , $17.6 million and $15.9 million , respectively. The Company awarded 71,567 , 65,476 and 80,780 market-based restricted stock units in 2018, 2017, and 2016, respectively, which entitle recipients to shares of common stock at the end of a three year vesting period. Recipients will earn shares, totaling between 0% and 175% of the number of units issued, based on the Company's total stockholder return relative to a specified peer group of financial institutions over the three year period. The Company awarded 71,560 market-based restricted stock units in 2015 that vested in 2018. The threshold performance for the units granted in 2015 was not met and, as a result, no shares were issued. The market-based restricted stock units are included in the preceding table as if the recipients earned shares equal to 100% of the units issued. A Monte Carlo simulation model was used to value the market-based restricted stock units at the time awarded. As of December 31, 2018 , there was $21.2 million of total unrecognized compensation cost related to nonvested share-based compensation arrangements (including share option and nonvested share awards) granted under the Omnibus Plan. At December 31, 2018 , the weighted-average period over which the unrecognized compensation expense is expected to be recognized was approximately two years.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company offers various derivatives, including interest rate swaps and foreign currency forward contracts, to its qualifying customers which can mitigate our exposure to market risk through the execution of off-setting positions with inter-bank dealer counterparties. This also permits the Company to offer customized risk management solutions to our customers. These customer accommodations and any offsetting financial contracts are treated as non-designated derivative instruments and carried at fair value through an adjustment to the statement of operations. Interest rate swap and foreign currency forward contracts involve the risk of dealing with counterparties and their ability to meet contractual terms. The net amount payable or receivable under interest rate swaps is accrued as an adjustment to interest income. The Company's credit exposure on interest rate swaps is limited to the Company's net favorable value and interest payments of all swaps to each counterparty. In such cases, collateral is generally required from the counterparties involved if the net value of the swaps exceeds a nominal amount. At December 31, 2018 , the Company’s credit exposure relating to interest rate swaps was approximately $17.4 million , of which $14.5 million was secured by the underlying collateral on customer loans and $2.9 million was secured by cash and investment securities. The Company also enters into mortgage banking derivatives which are classified as non-designated hedging derivatives. These derivatives include interest rate lock commitments provided to customers to fund certain mortgage loans to be sold into the secondary market and forward commitments for the future delivery of such loans. It is the Company's practice to enter into forward commitments for the future delivery of residential mortgage loans when interest rate lock commitments are entered into in order to economically hedge the effect of future changes in interest rates on its commitments to fund the loans as well as on its portfolio of mortgage loans held-for-sale. The Company had fair value commercial loan interest rate swaps, to hedge its interest rate risk, with an aggregate notional amount of $5 thousand at December 31, 2018 . For fair value hedges, the changes in fair values of both the hedging derivative and the hedged item were recorded in current earnings as other income. Interest rate swaps, swaptions, and treasury futures are used in order to lessen the price volatility of the mortgage servicing rights asset. The Company also uses forward commitments to buy to-be-announced ("TBA") mortgage securities. The Company does not intend to take delivery of these mortgage securities; it will sell the position before taking physical delivery. The resulting gain or loss reduces price volatility of the mortgage servicing rights asset due to changes in mortgage rates. These derivatives are recorded at their fair value on the consolidated balance sheets in other assets with changes in fair value recorded on the consolidated statements of operations in mortgage banking revenue in non-interest income. The Company’s derivative financial instruments are summarized below as of December 31, 2018 and 2017 (in thousands): Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Notional Estimated Notional Estimated Notional Estimated Notional Estimated Amount Fair Value Amount Fair Value Amount Fair Value Amount Fair Value Derivative instruments designated as hedges of fair value: Interest rate swap contracts (1) $ — $ — $ — $ — $ 5 $ 0 $ 58 $ (1 ) Stand-alone derivative instruments: (2) Interest rate swap contracts 1,803,901 31,222 1,563,109 21,217 1,803,901 (31,222 ) 1,563,109 (21,217 ) Interest rate options contracts 465,902 2,663 372,927 1,887 465,902 (2,663 ) 372,927 (1,887 ) Foreign exchange contracts 49,327 1,393 40,713 1,934 46,845 (1,117 ) 34,029 (1,759 ) Spot foreign exchange contracts 7,026 12 1,424 23 1,628 (4 ) 24 — Mortgage banking derivatives: Interest rate swap contracts 310,000 8,235 458,000 4,479 225,000 (6,079 ) 1,008,000 (14,360 ) Treasury futures contracts 152,500 794 28,000 39 5,000 (2 ) 30,000 (222 ) TBA mortgage securities 75,000 741 15,000 16 — — 100,000 (63 ) Forward loan sale commitments — — 259,000 333 22,500 (213 ) 483,500 (787 ) Interest rate lock commitments 12,671 108 404,557 1,571 — — — — Total stand-alone derivative instruments 2,876,327 45,168 3,142,730 31,499 2,570,776 (41,300 ) 3,591,589 (40,295 ) Total $ 2,876,327 $ 45,168 $ 3,142,730 $ 31,499 $ 2,570,781 $ (41,300 ) $ 3,591,647 $ (40,296 ) (1) Derivative instruments designated to hedge fixed-rate commercial real estate loans. (2) These portfolio swaps are not designated as hedging instruments under ASC Topic 815. Amounts included in other income in the consolidated statements of operations related to derivative financial instruments were as follows (in thousands): Years Ended December 31, 2018 2017 2016 Derivative instruments designated as hedges of fair value: Interest rate swap contracts $ 1 $ 3 $ 5 Stand-alone derivative instruments: Interest rate swap contracts 6,253 8,233 7,571 Interest rate options contracts — — 36 Foreign exchange contracts 612 269 970 Spot foreign exchange contracts 3,018 2,682 963 Mortgage related derivatives 454 (31,698 ) (1,509 ) Total stand-alone derivative instruments 10,337 (20,514 ) 8,031 Total $ 10,338 $ (20,511 ) $ 8,036 Methods and assumptions used by the Company in estimating the fair value of its interest rate swaps are discussed in Note 18 to consolidated financial statements. Certain instruments and transactions subject to an agreement similar to a master netting arrangement are eligible for offset in the consolidated balance sheet. The instruments and transactions would include derivatives, sale and repurchase agreements and reverse sale and repurchase agreements, and securities borrowing and securities lending arrangements. The Company’s derivative transactions with financial institution counterparties are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements which include “right of set-off” provisions. Under these agreements, there is generally a legally enforceable right to offset recognized amounts, and there may be an intention to settle such amounts on a net basis. The Company, however, does not generally offset such financial instruments for financial reporting purposes. Information about the Company's financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2018 is summarized below (in thousands): Financial Assets Financial Liabilities Gross Amount Recognized Gross Amount Offset Net Amount Recognized Gross Amount Recognized Gross Amount Offset Net Amount Recognized Derivatives: Interest rate swaps, caps and floors $ 18,791 $ — $ 18,791 $ 15,098 $ — $ 15,098 Foreign exchange contracts 896 — 896 540 — 540 Mortgage related derivatives 9,771 — 9,771 6,295 — 6,295 Total derivatives 29,458 — 29,458 21,933 — 21,933 Repurchase agreements — — — 312,239 — 312,239 Total $ 29,458 $ — $ 29,458 $ 334,172 $ — $ 334,172 Financial Assets Financial Liabilities Net Amount Recognized Financial Instruments Collateral Net Amount Net Amount Recognized Financial Instruments Collateral Net Amount Derivatives: Counterparty A $ 6,046 $ (3,993 ) $ (2,053 ) $ — $ 3,993 $ (3,993 ) $ — $ — Counterparty B 1,234 (151 ) (1,083 ) — 151 (151 ) — — Counterparty C 1,660 (713 ) (947 ) — 713 (713 ) — — Other counterparties 20,518 (16,599 ) (3,741 ) 178 17,076 (16,599 ) (358 ) 119 Total derivatives 29,458 (21,456 ) (7,824 ) 178 21,933 (21,456 ) (358 ) 119 Repurchase agreements — — — — 312,239 — (312,239 ) — Total $ 29,458 $ (21,456 ) $ (7,824 ) $ 178 $ 334,172 $ (21,456 ) $ (312,597 ) $ 119 Information about the Company's financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2017 is summarized below (in thousands): Financial Assets Financial Liabilities Gross Amount Recognized Gross Amount Offset Net Amount Recognized Gross Amount Recognized Gross Amount Offset Net Amount Recognized Derivatives: Interest rate swaps, caps and floors $ 11,659 $ — $ 11,659 $ 11,562 $ — $ 11,562 Foreign exchange contracts 1,013 — 1,013 953 — 953 Mortgage related derivatives 4,868 — 4,868 15,432 — 15,432 Total derivatives 17,540 — 17,540 27,947 — 27,947 Repurchase agreements — — — 232,789 — 232,789 Total $ 17,540 $ — $ 17,540 $ 260,736 $ — $ 260,736 Financial Assets Financial Liabilities Net Amount Recognized Financial Instruments Collateral Net Amount Net Amount Recognized Financial Instruments Collateral Net Amount Derivatives: Counterparty A $ 6,068 $ (6,068 ) $ — $ — $ 13,807 $ (6,068 ) $ (7,739 ) $ — Counterparty B 3,261 (3,261 ) — — 5,595 (3,261 ) (2,334 ) — Counterparty C 5,285 (3,640 ) — 1,645 3,640 (3,640 ) — — Other counterparties 2,926 (1,750 ) — 1,176 4,905 (1,750 ) (3,150 ) 5 Total derivatives 17,540 (14,719 ) — 2,821 27,947 (14,719 ) (13,223 ) 5 Repurchase agreements — — — — 232,789 — (232,789 ) — Total $ 17,540 $ (14,719 ) $ — $ 2,821 $ 260,736 $ (14,719 ) $ (246,012 ) $ 5

Operating Segments

Operating Segments	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Operating Segments	Operating Segments The Company's operations currently consist of three reportable operating segments: Banking, Leasing, and Mortgage Banking. The Company offers different products and services through its three segments. The accounting policies of the segments are generally the same as those of the consolidated company. The Banking Segment generates its revenues primarily from its lending, deposit gathering and fee business activities. The profitability of this segment's operations depends primarily on its net interest income after provision for credit losses, which is the difference between interest earned on interest earning assets and interest paid on interest bearing liabilities less provision for credit losses. The provision for credit losses is almost entirely dependent on changes in the Banking Segment's loan portfolio and management’s assessment of the collectability of the loan portfolio as well as prevailing economic and market conditions. The Banking Segment is also subject to an extensive system of laws and regulations that are intended primarily for the protection of depositors and other customers, federal deposit insurance funds and the banking system as a whole. These laws and regulations govern such areas as capital, permissible activities, allowance for loan and lease losses, loans and investments, and rates of interest that can be charged on loans. The Leasing Segment generates its revenues through lease originations and related services. The Leasing Segment invests directly in equipment that the Company leases (referred to as direct finance, leveraged or operating leases) to "Fortune 1000," middle-market companies and health care providers located throughout the United States. The lease portfolio is made up of various kinds of equipment, generally technology related, such as computer systems, satellite equipment, medical equipment and general manufacturing, industrial, construction and transportation equipment. The Leasing Segment also specializes in selling third party equipment maintenance contracts to large companies. The Mortgage Banking Segment originates residential mortgage loans for sale to investors and for the Company's portfolio through its retail and third party originator channels. This segment also services residential mortgage loans for various investors and for loans owned by the Company. The Mortgage Banking Segment is subject to an extensive system of laws and regulations that are intended primarily for the protection of customers. On April 12, 2018, the Company announced the discontinuation of its national mortgage origination business, which includes substantially all originations outside of the Company's consumer banking footprint in the Chicagoland area. The Company is retaining the mortgage servicing asset, residential mortgage loans, and Chicagoland area originations. The Company expects to stop operating its mortgage business as a defined segment with separate Mortgage Banking Segment reporting in 2019. Net interest income for the Leasing and Mortgage Banking segments include adjustments based on the Company's internal funds transfer pricing model. Non-interest income for the Leasing Segment includes income on loans originated for the sole purpose of funding equipment purchases related to leases at the Company's lease subsidiaries. The following tables present summary financial information for the reportable segments (in thousands): Banking Leasing Mortgage Banking Consolidated Year ended December 31, 2018 Net interest income $ 592,514 $ 9,563 $ 35,726 $ 637,803 Provision for credit losses 46,104 1,204 (107 ) 47,201 Non-interest income 179,136 100,140 63,353 342,629 Non-interest expense (1) 486,212 63,897 130,951 681,060 Income (loss) before income taxes 239,334 44,602 (31,765 ) 252,171 Income tax expense (benefit) 38,602 8,158 (8,504 ) 38,256 Net income (loss) $ 200,732 $ 36,444 $ (23,261 ) $ 213,915 Total assets $ 17,070,713 $ 1,464,380 $ 1,671,933 $ 20,207,026 Year ended December 31, 2017 Net interest income $ 550,499 $ 9,902 $ 41,976 $ 602,377 Provision for credit losses 16,555 3,858 1,180 21,593 Non-interest income 174,120 86,029 109,225 369,374 Non-interest expense (1) 462,055 57,331 141,957 661,343 Income before income taxes 246,009 34,742 8,064 288,815 Income tax expense (benefit) 65,137 (51,140 ) (29,222 ) (15,225 ) Net income $ 180,872 $ 85,882 $ 37,286 $ 304,040 Total assets $ 16,448,960 $ 1,403,690 $ 2,234,290 $ 20,086,940 Year ended December 31, 2016 Net interest income $ 475,133 $ 9,415 $ 33,343 $ 517,891 Provision for credit losses 18,583 295 685 19,563 Non-interest income 153,250 73,503 151,397 378,150 Non-interest expense (1) 421,733 48,450 152,915 623,098 Income before income taxes 188,067 34,173 31,140 253,380 Income tax expense 53,263 13,525 12,456 79,244 Net income $ 134,804 $ 20,648 $ 18,684 $ 174,136 Total assets $ 16,368,881 $ 1,224,169 $ 1,709,267 $ 19,302,317 (1) Includes merger related and repositioning expenses of $15.1 million , $9.9 million and $23.7 million in the Banking Segment for the years ended December 31, 2018 , 2017 , and 2016 , respectively, and $32.4 million in the Mortgage Banking Segment for the year ended December 31, 2018.

Condensed Parent Company Financ

Condensed Parent Company Financial Information	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Parent Company Financial Information	Condensed Parent Company Financial Information The condensed financial statements of MB Financial, Inc. (parent company only) are presented below: Balance Sheets (In thousands) December 31, 2018 2017 Assets Cash $ 106,808 $ 219,086 Investments in subsidiaries 2,990,651 2,961,822 Other assets 85,291 73,438 Total assets $ 3,182,750 $ 3,254,346 Liabilities and Stockholders’ Equity Short-term borrowings $ — $ — Long-term borrowings — 10,000 Junior subordinated notes issued to capital trusts 121,118 211,494 Other liabilities 26,784 23,029 Stockholders’ equity 3,034,848 3,009,823 Total liabilities and stockholders’ equity $ 3,182,750 $ 3,254,346 Statements of Operations (In thousands) Years Ended December 31, 2018 2017 2016 Dividends from subsidiaries $ 200,000 $ 78,846 $ 112,000 Interest and other income (908 ) 4,148 1,913 Interest and other expense 29,167 18,990 14,990 Income before income tax benefit and equity in undistributed net income of subsidiaries 169,925 64,004 98,923 Income tax benefit (8,045 ) (8,253 ) (5,303 ) Income before equity in undistributed net income of subsidiaries 177,970 72,257 104,226 Equity in undistributed net income of subsidiaries 35,945 231,783 69,910 Net income 213,915 304,040 174,136 Dividends on preferred shares 12,100 8,007 8,009 Return from preferred stockholders due to redemption (15,280 ) — — Net income available to common stockholders $ 217,095 $ 296,033 $ 166,127 Statements of Cash Flows (In thousands) Years Ended December 31, 2018 2017 2016 Cash Flows From Operating Activities Net income $ 213,915 $ 304,040 $ 174,136 Adjustments to reconcile net income to net cash provided by operating activities: Compensation expense for share-based payment plans 18,727 17,476 16,868 Equity in undistributed net income of subsidiaries (35,945 ) (231,783 ) (69,910 ) Loss on extinguishment of debt 11,898 — — Change in other assets and other liabilities (14,172 ) 163 (28,546 ) Net cash provided by operating activities 194,423 89,896 92,548 Cash Flows From Investing Activities Investments in and advances to subsidiaries — — (2,000 ) Net cash paid in business acquisition — — (83,163 ) Net cash used in investing activities — — (85,163 ) Cash Flows From Financing Activities Treasury stock transactions, net (1,685 ) (3,271 ) (3,837 ) Stock options exercised 4,063 2,504 1,410 Dividends paid on common stock (81,883 ) (69,346 ) (58,177 ) Dividends paid on preferred stock (14,100 ) (8,007 ) (8,009 ) Issuance of preferred stock, net of issuance costs — 194,719 — Redemption of preferred stock (100,000 ) — — Net decrease short-term borrowings — (10,000 ) (15,000 ) Principal paid on long-term borrowings (10,000 ) (4,000 ) (2,000 ) Redemption of junior subordinated notes issued to capital trusts (103,096 ) — — Net cash (used in) provided by financing activities (306,701 ) 102,599 (85,613 ) Net (decrease) increase in cash (112,278 ) 192,495 (78,228 ) Cash: Beginning of year 219,086 26,591 104,819 End of year $ 106,808 $ 219,086 $ 26,591

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Preferred Stock	Preferred Stock On August 18, 2014, in connection with the Taylor Capital merger, the Company issued one share of its Perpetual Non-Cumulative Preferred Stock, Series A (“Company Series A Preferred Stock”), in exchange for each of the 4,000,000 outstanding shares of Taylor Capital’s Perpetual Non-Cumulative Preferred Stock, Series A. Holders of the Company Series A Preferred Stock were entitled to receive, when as and if declared by the Company’s board of directors, non-cumulative cash dividends on the liquidation preference, which was $25 per share, at a rate of 8.00% per annum, payable quarterly. The Company Series A Preferred Stock was included in Tier 1 capital for regulatory capital purposes. On February 15, 2018, the Company redeemed all of the 4,000,000 issued and outstanding shares of Company Series A Preferred Stock at a redemption price of $25.00 per share, or $100.0 million in the aggregate. The excess carrying amount of the Series A Preferred Stock in the amount of $15.3 million was retained in stockholders' equity and reflected as income available to common stockholders, which was included in the calculation of earnings per common share for the year ended December 31, 2018. On August 24, 2016, in connection with the American Chartered merger, the Company issued one share of its Cumulative Voting Convertible Preferred Stock, Series B ("Company Series B Preferred Stock"), in exchange for each of the 525 shares of American Chartered's Series D Preferred Stock outstanding immediately prior to the merger whose holders did not elect to receive the same consideration in the merger as holders of American Chartered Common Stock, based on the number of shares of American Chartered Common Stock into which each such share of American Chartered Series D Preferred Stock would otherwise then be convertible. Holders of the Company Series B Preferred Stock were entitled to receive cumulative cash dividends on the liquidation preference amount, which was $1,000 per share, at a rate of 8.00% per annum, had the right to vote on all matters upon which holders of the Company's common stock were entitled to vote and had the right to convert each share into shares of the Company's common stock at any time. The Company Series B Preferred stock had a mandatory conversion date of September 20, 2017. The Company Series B Preferred Stock was included in Tier 2 capital for regulatory capital purposes. During the third quarter of 2016, 400 shares of the Company Series B Preferred stock were voluntarily converted by the holders of such shares into shares of the Company's common stock. On September 20, 2017, the remaining 125 of the Company Series B Preferred stock were converted into shares of the Company's common stock pursuant to the mandatory conversion provision referred to above. On November 22, 2017, the Company issued 8,000,000 depositary shares, each representing a 1/40th interest in a share of its Non-Cumulative Preferred Stock, Series C (“Company Series C Preferred Stock”). Holders of the Company Series C Preferred Stock are entitled to receive, when as and if declared by the Company's board of directors, non-cumulative cash dividends on the liquidation preference, which is $25 per depositary share (equivalent to $1,000 per share of preferred stock), at a rate of 6.00% per annum, payable quarterly. The Company Series C Preferred Stock is included in Tier 1 capital for regulatory capital purposes and is redeemable at the option of the Company at a redemption price of $25 per depositary share, plus any declared and unpaid dividends, (i) in whole or in part from time to time, on any dividend payment date on or after November 25, 2022, and (ii) in whole but not in part prior to November 25, 2022, within 90 days following a “regulatory capital treatment event,” as defined in the terms of the Company Series C Preferred Stock. The Company must receive the approval of the Federal Reserve Board prior to any redemption of the Company Series C Preferred Stock.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Event On February 6, 2019, the Company signed a termination agreement to exit the loss-share agreements with the FDIC that covered losses on consumer related loans acquired in connection with the Heritage, Benchmark, Broadway, and New Century FDIC-assisted transactions. Under the terms of the termination agreement, the Company made a payment of $15.9 million to the FDIC for the early termination of the loss-share agreements. The Company recorded a pre-tax gain of approximately $5.0 million in the fourth quarter of 2018 to eliminate the clawback liability and recognize the termination payment amount. The Company had $12.1 million in loans that were covered under these loss-share agreements at December 31, 2018.

Definitive Merger Agreement

Definitive Merger Agreement	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Definitive Merger Agreement	Business Combinations American Chartered Bancorp, Inc. On August 24, 2016, American Chartered Bancorp, Inc. ("American Chartered"), an Illinois corporation, was merged (the "American Chartered Merger") with and into the Company, pursuant to the Agreement and Plan of Merger, dated as of November 20, 2015 (the "Merger Agreement"), by and between the Company and American Chartered. This transaction continues to solidify the Company's market position in Chicago. At the effective time of the merger (the "American Chartered Effective Time"), (i) each share of the common stock, no par value, of American Chartered ("American Chartered Common Stock") that was issued and outstanding immediately prior to the American Chartered Effective Time, (ii) each share of American Chartered’s 8% Cumulative Voting Convertible Preferred Stock, Series D ("American Chartered Series D Preferred Stock"), that was issued and outstanding immediately prior to the American Chartered Effective Time whose holder elected pursuant to American Chartered’s charter to receive the same consideration in the American Chartered Merger as holders of American Chartered Common Stock, based on the number of shares of American Chartered Common Stock into which such share of American Chartered Series D Preferred Stock would otherwise then be convertible, and (iii) each share of American Chartered Non-Voting Perpetual Preferred Stock, Series F, that was issued and outstanding immediately prior to the American Chartered Effective Time, was converted into the right to receive, subject to the election and proration procedures set forth in the Merger Agreement: (1) cash in the amount of $9.30 (the "Cash Consideration") or (2) 0.2732 shares of the Company's common stock, with cash paid in lieu of fractional Company shares determined by multiplying the fractional Company share amount by $39.01 (the average closing sale price of the Company's common stock for the five full trading days ending on August 23, 2016) (the "Stock Consideration"). The holders of such shares of American Chartered stock also could elect to receive a combination of the Cash Consideration and the Stock Consideration for their shares. Each share of American Chartered Series D Preferred Stock whose holder did not elect to receive the same consideration in the American Chartered Merger as holders of American Chartered Common Stock, based on the number of shares of American Chartered Common Stock into which such share of American Chartered Series D Preferred Stock would otherwise then be convertible, was converted into the right to receive one share of the Company's 8% cumulative voting convertible preferred stock, Series B. Consideration paid was $487.4 million , including $382.8 million in common stock ( 9.7 million shares), $102.3 million in cash and $2.3 million in preferred stock and stock-based awards assumed. The $102.3 million in cash consideration includes payments for the value of the net option shares of the American Chartered stock options pursuant to the Merger Agreement. This business combination was accounted for under the acquisition method of accounting. Accordingly, the results of operations of the acquired company have been included in the Company’s results of operations since the date of acquisition. Under this method of accounting, the assets acquired, liabilities assumed and consideration paid are recorded at their estimated fair values. The excess cost over fair value of net assets acquired is recorded as goodwill. As the consideration paid for American Chartered exceeded the net assets acquired, goodwill of $274.9 million was recorded on the acquisition and allocated to the banking segment. Goodwill recorded in the transaction, which reflects the increased Chicago market share and related synergies expected from the combined operations, is not tax deductible. The amounts recognized for the business combination in the financial statements have been determined to be final as of March 31, 2017. Estimated fair values of the assets acquired and liabilities assumed in the American Chartered Merger, as of the closing date of the transaction were as follows (in thousands): August 24, 2016 ASSETS Cash and cash equivalents $ 93,307 Investment securities available for sale 505,564 Non-marketable securities - FRB and FHLB Stock 16,000 Loans 1,942,548 Premises and equipment 39,048 Cash surrender value of life insurance 59,917 Goodwill 274,885 Other intangibles 25,452 Other real estate owned 3,960 Other assets 31,408 Total assets $ 2,992,089 LIABILITIES Deposits $ 2,389,327 Short-term borrowings 48,305 Long-term borrowings 16,000 Junior subordinated notes issued to capital trusts 28,075 Accrued expenses and other liabilities 22,966 Total liabilities $ 2,504,673 Total identifiable net assets $ 487,416 Consideration: Market value of common stock at $39.28 per share at August 24, 2016 (9,744,636 shares of common stock issued) $ 382,769 Series B preferred stock at $2,337.97 per share at August 24, 2016 (525 shares of preferred stock issued) (1) 1,227 Stock-based compensation attributed to pre-business combination service 1,103 Cash paid 102,317 Total fair value of consideration, excluding Series B preferred stock $ 487,416 (1) Per share fair value amount determined as if the shares of Series B were converted into shares common stock. Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date without a carryover of the related allowance for loan and lease losses. These acquired loans are segregated into three types: pass rated loans with no discount attributable to credit quality, non-impaired loans with a discount attributable at least in part to credit quality and impaired loans with evidence of significant credit deterioration. • Pass rated loans (typically performing loans) are accounted for in accordance with ASC Topic 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination. • Non-impaired loans (typically performing substandard loans) are accounted for in accordance with ASC Topic 310-30 if they display at least some level of credit deterioration since origination. • Impaired loans (typically substandard loans on non-accrual status) are accounted for in accordance with ASC Topic 310-30 as they display significant credit deterioration since origination. For pass rated loans (non-purchased credit-impaired loans), the difference between the estimated fair value of the loans and the principal outstanding is accreted over the remaining life of the loans. In accordance with ASC Topic 310-30, for both purchased non-impaired loans (performing substandard loans) and purchased credit-impaired loans, the loans are pooled by loan type and the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan pools when there is a reasonable expectation about the amount and timing of such cash flows. The following table presents the acquired loans as of the acquisition date (in thousands): Purchased Purchased Non-Credit-Impaired Fair value $ 62,104 $ 1,880,444 Gross contractual amounts receivable 93,490 2,149,868 Best estimate of contractual cash flows not expected to be collected (1) 22,293 114,154 Best estimate of contractual cash flows expected to be collected 71,197 2,035,714 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default. During 2017, the fair value estimates of loans increased by $1.8 million compared to previously reported balances at December 31, 2016, which decreased the deferred tax asset by $733 thousand and goodwill by $1.1 million as of December 31, 2017. The accretable discount for the non-purchased credit-impaired loans was $20.7 million as of the date of the acquisition. The non-accretable and accretable discount for the purchased credit-impaired loans was $18.4 million and $5.3 million , respectively, as of the date of the acquisition. The Company incurred costs of $2.0 million directly related to the consummation of the American Chartered Merger for the year ended December 31, 2016, which is recorded in professional and legal fees on the statement of operations. The data processing systems were converted in September 2016. The following table provides the unaudited pro forma information for the results of operations for the year ended December 31, 2016, as if the acquisition had occurred January 1, 2015. The pro forma results combine the historical results of American Chartered into the Company's consolidated statement of operations including the impact of certain acquisition accounting adjustments including loan discount accretion, investment securities discount accretion, intangible assets amortization, deposit premium accretion and borrowing discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2015. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The merger related expenses that have been recognized are included in net income in the table below. Year Ended December 31, 2016 (in thousands) Total revenues (net interest income plus non-interest income) $ 975,188 Net income 197,046 Revenues and earnings of the acquired company since the acquisition date have not been disclosed as it is not practicable as American Chartered was merged into the Company and separate financial information is not readily available. Definitive Merger Agreement On May 20, 2018, the Company entered into an Agreement and Plan of Merger (the "Merger Agreement") with Fifth Third Bancorp, an Ohio corporation ("Fifth Third"), pursuant to which a newly formed subsidiary of Fifth Third will be merged with and into the Company, with the Company as the surviving corporation (the “Merger”). At the effective time of the Merger (the "Effective Time"), each outstanding share of Company Common Stock will be converted into the right to receive (i) 1.45 shares of Fifth Third common stock ("Fifth Third Common Stock"), and (ii) $5.54 in cash (collectively, the "Merger Consideration"). The Company’s Series C Preferred Stock will remain outstanding and unchanged (except as modified by the Charter Amendment, as defined below) as preferred stock of the Company, which will be a subsidiary of Fifth Third. Pursuant to an amendment to the Company's charter (the "Charter Amendment") that will become effective immediately prior to consummation of the Merger, the holders of Company Series C Preferred Stock will have the right to vote with the holders of Company Common Stock as a single class on all matters submitted to a vote of such common stockholders. Upon completion of the Merger, Fifth Third, as the sole holder of Company Common Stock, will control the Company. Following completion of the Merger, the holders of Company Series C Preferred Stock will vote with Fifth Third as a single class on all matters submitted to a vote of Fifth Third, as the sole common stockholder of the Company. Thus, the voting rights that will be conferred upon the holders of Company Series C Preferred Stock by the Charter Amendment will continue to apply with respect to the Company, and not Fifth Third, following completion of the Merger. At the Effective Time, each option granted by the Company to purchase shares of Company Common Stock (the "Company Options") will be converted into an option to purchase shares of Fifth Third Common Stock on the same terms and conditions as were applicable to such Company Options prior to the Merger, subject to certain adjustments to the exercise price and the number of shares of Fifth Third Common Stock issuable upon exercise of such option in accordance with the Merger Agreement. In addition, each Company restricted stock award, restricted stock unit and performance-based award (the "Company Equity Awards") that remains unvested and would not automatically vest by its terms at the Effective Time will be assumed by Fifth Third and converted into a number of shares of Fifth Third Common Stock (the "Assumed Equity Awards") with such shares being subject to certain adjustments in accordance with the Merger Agreement but otherwise remaining subject to the same terms and conditions as applicable immediately prior to such conversion. Each Company Equity Award that is outstanding immediately prior to the Effective Time that is not assumed under the Merger Agreement will be canceled and converted automatically into the right to receive the Merger Consideration. On September 18, 2018, the Company received the requisite approvals of its common stockholders for the Merger. The Merger is subject to regulatory approvals and certain other customary closing conditions.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Financial Statement Presentation	Basis of Financial Statement Presentation: The consolidated financial statements include the accounts of the Company and its subsidiaries. Significant intercompany items and transactions have been eliminated in consolidation. The accounting and reporting policies of the Company conform to accounting principles generally accepted in the United States of America and general practices within the financial services industry. In accordance with applicable accounting standards, the Company does not consolidate statutory trusts established for the sole purpose of issuing trust preferred securities and related trust common securities. See Note 12 below for more detail. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and revenues and expenses for the year. Actual results could differ from those estimates. Areas involving the use of management’s estimates and assumptions, which are more susceptible to change in the near term include the allowance for loan and lease losses; residual value of direct finance, leveraged, and operating leases; valuation of mortgage servicing rights; income tax accounting; fair value measurements for assets and liabilities; and goodwill.
Cash and cash equivalents	Cash and cash equivalents: For purposes of reporting cash flows, cash and cash equivalents includes cash on hand, amounts due from banks (including cash items in process of clearing), interest bearing deposits with banks, with original maturities of 90 days or less.
Investment securities	Investment securities: Securities classified as available for sale are those securities that the Company intends to hold for an indefinite period of time, but not necessarily to maturity. Any decision to sell a security classified as available for sale is based on various factors, including movements in interest rates, changes in the maturity mix of assets and liabilities, liquidity needs, regulatory capital considerations, and other factors. Securities available for sale are reported at fair value with unrealized gains or losses reported as accumulated other comprehensive income, net of the related deferred tax effect. Securities classified as held to maturity are those securities that the Company intends to hold until maturity and are reported at amortized cost. 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 level-yield method. In determining the estimated life of a mortgage-related security, certain judgments are required as to the timing and amount of future principal prepayments. These judgments are made based upon the actual performance of the underlying security and the general market consensus regarding changes in mortgage interest rates and underlying prepayment estimates. Amortization of premium and accretion of discount is included in interest income from the related security. Realized gains or losses, determined on the basis of the cost of specific securities sold, are included in earnings. The Company evaluates the portfolio for impairment each quarter. In estimating other-than-temporary losses, the Company considers the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, and whether the Company is more likely than not to sell the security before recovery of its cost basis. If the Company intends to sell an impaired security, the Company records an other-than-temporary loss in an amount equal to the entire difference between the fair value and amortized cost. If a security is determined to be other-than-temporarily impaired, but the Company does not intend to sell the security, only the credit portion of the estimated loss is recognized in earnings, with the other portion of the loss recognized in other comprehensive income.
Federal Home Loan Bank and Federal Reserve Bank stock	Federal Home Loan Bank and Federal Reserve Bank stock: The Company owns investments in the stock of the Federal Reserve Bank of Chicago (“FRB”) and the Federal Home Loan Bank of Chicago (“FHLB”). No ready market exists for these stocks, and they have no quoted market values. The Bank, as a member of the Federal Reserve System and the FHLB, is required to maintain an investment in the capital stock of the FRB and FHLB. The stock is redeemable at par by the FRB and FHLB, respectively, and is, therefore, carried at cost and periodically evaluated for impairment.
Loans held for sale	Loans held for sale: Mortgage loans originated and intended for sale in the secondary market are reflected at fair value as elected. Changes in the fair value are recognized in mortgage banking revenue on the Company's Consolidated Statements of Operations.
Mortgage Loan Representation and Warranty Reserve	Mortgage Loan Representation and Warranty Reserve: The Company originates and sells residential mortgage loans in the secondary market. When the Company sells mortgage loans, it makes customary representations and warranties to the purchasers about various characteristics of each loan, such as the ownership of the loan, the validity of the lien securing the loan, the nature and extent of underwriting standards applied and the types of documentation being provided. These representations and warranties are generally enforceable over the life of the loan. If a defect in the origination process is identified, the Company may be required to either repurchase the loan or indemnify the purchaser for losses it sustains on the loan. If there are no such defects, the Company has no liability to the purchaser for losses it may incur on such loans. Representation and warranty reserves were $5.3 million and $7.0 million as of December 31, 2018 and 2017, respectively. The Company maintains a representation and warranty reserve to account for the expected losses related to loans it might be required to repurchase or the indemnity payments it may have to make to purchasers. The representation and warranty reserve reflects management's best estimate of probable lifetime loss. The reserve considers both the estimate of expected losses on loans sold during the current accounting period as well as adjustments to the Company's previous estimate of expected losses on loans sold. Factors considered include borrower performance, repurchase demand behavior, and historical loan defect experience. Management monitors the adequacy of the overall reserve and makes adjustments to the level of reserve, as necessary, after consideration of other qualitative factors. At the time a loan originated for sale is funded, the representation and warranty reserve is recorded as a decrease in mortgage banking revenue on the Consolidated Statements of Operations and recorded in accrued interest, taxes and other liabilities on the Company's Consolidated Balance Sheets. Changes to the reserve are recorded as an increase or decrease to mortgage banking revenue on the Consolidated Statements of Operations.
Loans and leases	Loans and leases: Loans are stated at the amount of unpaid principal reduced by the allowance for loan and lease losses and unearned income. Direct finance and leveraged leases are included as lease loans for financial statement purposes. Direct finance leases are stated as the sum of remaining minimum lease payments from lessees plus estimated residual values less unearned lease income. Leveraged leases are stated as the sum of remaining minimum lease payments from lessees (less nonrecourse debt payments) plus estimated residual values less unearned lease income. On an annual basis, management reviews the lease residuals for potential impairment. Unearned lease income on direct finance and leveraged leases is recognized over the lives of the leases using the level-yield method. Loan origination and commitment fees and certain direct loan origination costs are deferred and the net amount amortized as an adjustment of the related loan’s yield. The Company is amortizing these amounts over the contractual life of the loan. Commitment fees based upon a percentage of a customer’s unused line of credit and fees related to standby letters of credit are recognized over the commitment period. Interest income is accrued daily on the Company’s outstanding loan balances. The accrual of interest on loans is discontinued at the time the loan is 90 days past due unless the credit is well-secured and in process of renewal or collection. Past due status is based on contractual terms of the loan. In all cases, loans are placed on non-accrual or charged-off at an earlier date if collection of principal or interest is considered doubtful. All interest accrued but not collected for loans that are placed on non-accrual or charged-off is reversed against interest income. For impaired loans, accrual of interest is discontinued on a loan when management believes, after considering collection efforts and other factors, the borrower’s financial condition is such that collection of interest is doubtful. Cash collections on impaired loans are generally credited to the loan balance, and no interest income is recognized on those loans until the principal balance has been determined to be collectible. Loans, other than those included in large groups of smaller-balance homogeneous loans, are considered impaired when it is probable the Company will be unable to collect all contractual principal and interest payments due in accordance with the terms of the loan agreement. Impaired loans include non-accrual loans and loans classified as troubled debt restructurings. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate or, as a practical expedient, based on the loan’s observable market price or the fair value of the collateral if the loan is collateral dependent. The amount of impairment, if any and any subsequent changes are charged against the allowance for loan and lease losses.
Troubled debt restructurings	Troubled debt restructurings: A loan is classified as a troubled debt restructuring when a borrower is experiencing financial difficulties that leads to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include rate reductions, principal forgiveness, deferral of past due interest or principal, extension of maturity date, modification of amortization schedules, redemption of past due taxes and other actions intended to minimize potential losses. In determining whether a debtor is experiencing financial difficulties, the Company considers if the debtor is in payment default or would be in payment default in the foreseeable future without the modification, the debtor declared or is in the process of declaring bankruptcy, there is substantial doubt that the debtor will continue as a going concern, the debtor has securities that have been or are in the process of being delisted, the debtor’s entity-specific projected cash flows will not be sufficient to service any of its debt, or the debtor cannot obtain funds from sources other than the existing creditors at a market rate for debt with similar risk characteristics. In determining whether the Company has granted a concession, the Company assesses, if it does not expect to collect all amounts due, whether the current value of the collateral will satisfy the amounts owed, whether additional collateral or guarantees from the debtor will serve as adequate compensation for other terms of the restructuring, and whether the debtor otherwise has access to funds at a market rate for debt with similar risk characteristics. A loan that is modified at a market rate of interest will not be classified as troubled debt restructuring in the calendar year subsequent to the restructuring if it is in compliance with the modified terms. Payment performance prior and subsequent to the restructuring is taken into account in assessing whether it is likely that the borrower can meet the new terms. Under certain circumstances, a loan may be returned to accrual at the time of restructuring. A period of sustained repayment for at least six months generally is required for return to accrual status. Consistent with regulatory guidance, a troubled debt restructuring loan that is subsequently modified in another restructuring agreement but has shown sustained performance will be removed from troubled debt restructuring status provided the modified terms were market based at the time of modification.
Allowance for loan and lease losses	Allowance for loan and lease losses: The allowance for loan and lease losses ("ALLL") is established through a provision for credit losses charged to expense. Loans are charged against the ALLL when management believes that collectability of the principal is unlikely. The allowance is an amount that management believes will be appropriate to absorb probable losses on existing loans, based on an evaluation of the collectability of loans and prior loss and recovery experience as appropriate under GAAP. The ALLL is based on management’s evaluation of the loan portfolio giving consideration to the nature and volume of the loan portfolio, the value of underlying collateral, overall portfolio quality, review of specific problem loans, prevailing economic conditions that may affect the borrower’s ability to pay, as well as other qualitative and environmental factors. While management uses the best information available to make its evaluation, future adjustments to the allowance may be necessary if there are significant changes in economic conditions. In addition, regulatory agencies, as an integral part of their examination process, periodically review MB Financial Bank’s ALLL, and may require it to recognize adjustments to its allowance based on their judgments of information available to them at the time of their examinations. The ALLL is comprised of three elements: a commercial related general loss reserve; a commercial related specific reserve for impaired loans; and a consumer related reserve for smaller-balance homogenous loans. Each element is discussed below. Commercial Related General Loss Reserve - We maintain a general loan loss reserve for the four categories of commercial related loans in our portfolio - commercial loans, commercial loans collateralized by the assignment of lease payments (lease loans), commercial real estate loans and construction real estate loans. Under our loan risk rating system, each loan, with the exception of those included in large groups of smaller-balance homogeneous consumer related loans, is risk rated between one and nine by the originating loan officer, Senior Credit Management, Loan Review or loan committee. A loan rated "one" represents a loan least likely to default, while a loan rated " nine " represents a loss. The probability of loans defaulting for each risk rating, sometimes referred to as default factors, are estimated based on the frequency with which loans migrate from one risk rating to another and to default status over time. We use a loan loss reserve model that incorporates loan risk rating migrations and historical default data over a multi-year period to develop estimated default factors ("EDFs"). The model tracks annual loan rating migrations by loan type over the last 18 years and is adjusted to reflect average losses over an economic cycle. EDFs are updated annually in December. EDFs are multiplied by individual loan balances in each risk-rating category and by an historical loss given default estimate for each loan type (which incorporates recoveries) to determine the appropriate allowance by loan type. This approach is applied to the commercial, lease, commercial real estate, and construction real estate components of the portfolio. To account for current economic conditions, the general allowance for loan and lease losses also includes macroeconomic factor adjustments. Macroeconomic factors adjust the ALLL upward or downward based on the current point in the economic cycle using predictive economic data and are applied to the loan loss model through a separate allowance element for the commercial, commercial real estate, construction real estate and lease loan components. To determine our macroeconomic factors, we use specific economic data that are deemed predictive of future credit losses. We tested over 20 economic variables (U.S. manufacturing index, unemployment rate, U.S. GDP growth, etc.). We review this data annually to determine that such relationships continue to exist. We currently use the following macroeconomic indicators in our macroeconomic factor computation: • Commercial loans and lease loans: BBB-rated debt yield and number of civilians unemployed for 27 weeks or more. • Commercial real estate loans and construction loans: Non-performing loans to total loans, Capacity Utilization: Total Industry (percent of capacity), and the Chicago Fed's National Financial Conditions Index. Using the indicators noted above, a net charge-off rate is estimated and compared to our cycle average rate, resulting in a macroeconomic adjustment factor. The macroeconomic adjustment factor is applied to each commercial loan type. Each year, we evaluate the predictive nature of the macroeconomic factors and re-calibrate the macroeconomic models as needed. Commercial Related Specific Reserves - The ALLL also includes specific reserves on impaired commercial related loans. A loan is considered to be impaired when management believes, after considering collection efforts and other factors, the borrower’s financial condition is such that the collection of all contractual principal and interest payments due is doubtful. At each quarter-end, impaired loans are reviewed individually, with adjustments made to the general calculated reserve for each loan as deemed necessary. Specific adjustments are made depending on expected cash flows and/or the value of the collateral securing each loan. Generally, the Company obtains a current external appraisal (within 12 months) on real estate secured impaired loans. Our appraisal policy is designed to comply with the Interagency Appraisal and Evaluation Guidelines. As part of our compliance with these guidelines, we maintain an internal Appraisal Review Department that engages and reviews all third party appraisals. In addition, each impaired commercial loan with real estate collateral is reviewed quarterly by our appraisal department to determine that the most recent valuation remains appropriate during subsequent quarters until the next appraisal is received. If considered necessary by our appraisal department, the appraised value may be further discounted to reflect current values. Other valuation techniques are also used to value non-real estate assets. Discounts may be applied in the impairment analysis used for general business assets ("GBA"). Examples of GBA include accounts receivable, inventory, and any marketable securities pledged. The discount is used to reflect collection risk in the event of default that may not have been included in the valuation of the asset. Consumer Related Reserves - Pools of homogeneous loans with similar risk and loss characteristics are also assessed for probable losses. These loan pools include consumer, residential real estate, home equity, credit cards and indirect vehicle loans. Migration probabilities obtained from past due roll rate analyses and historical loss rates are applied to current balances to forecast charge-offs over a one -year time horizon. We consistently apply our methodology for determining the appropriateness of the allowance for loan and lease losses but may adjust our methodologies and assumptions based on historical information related to charge-offs and management's evaluation of the loan portfolio. In this regard, we periodically review the following to validate our allowance for loan and lease losses: historical net charge-offs as they relate to prior periods' allowance for loan and lease loss, comparison of historical loan migration in past years compared to the current year, overall credit trends and ratios, any significant changes in loan concentrations, lending policies, and emerging impacts in the legal/regulatory landscape. In reviewing this data, we adjust qualitative factors within our allowance methodology to appropriately reflect any changes warranted by the validation process.
Acquired loans	Acquired loans: Purchased loans acquired in a business combination are recorded at estimated fair value on their purchase date without a carryover of the related allowance for loan and lease losses. These acquired loans are segregated into three types: pass rated loans with no discount attributable to credit quality, non-impaired loans with a discount attributable at least in part to credit quality and impaired loans with evidence of significant credit deterioration. • Pass rated loans (typically performing loans) are accounted for in accordance with ASC Topic 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination. • Non-impaired loans (typically performing substandard loans) are accounted for in accordance with ASC Topic 310-30 if they display at least some level of credit deterioration since origination. • Impaired loans (typically substandard loans on non-accrual status) are accounted for in accordance with ASC Topic 310-30 as they display significant credit deterioration since origination. For pass rated loans (non-purchased credit-impaired loans), the difference between the estimated fair value of the loans and the principal outstanding is accreted over the remaining life of the loans. The Company anticipates recording a provision for the acquired portfolio in future quarters related to renewing acquired loans which will offset a substantial portion of the accretion from the pass rated loans. In accordance with ASC Topic 310-30, for both purchased non-impaired loans (performing substandard loans) and purchased credit-impaired loans, the loans are pooled by loan type and the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. Further, any excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable yield and is recognized into interest income over the remaining life of the loan pools when there is a reasonable expectation about the amount and timing of such cash flows. Substantially all of the loans acquired in transactions with the FDIC displayed at least some level of credit deterioration and as such are included as non-impaired and impaired loans as described immediately above.
Lease investments	Lease investments: The Company’s investment in operating leases is reported as lease investments, net. Rental income on operating leases is recognized as income over the lease term according to the provisions of the lease, which is generally on a straight-line basis. The investment in equipment in operating leases is stated at cost less depreciation using the straight-line method generally over a life of five years or less.
Premises and equipment	Premises and equipment: Premises and equipment are carried at cost less accumulated depreciation and amortization. Depreciation and amortization is computed by the straight-line method over the estimated useful lives of the assets. Useful lives generally range from three to seven years for computer equipment and software, five to 10 years for furniture and equipment, and five to 39 years for buildings and building improvements. Land improvements are amortized over a period of 15 years and leasehold improvements are amortized over the term of the related lease or the estimated useful lives of the improvements, whichever is shorter. Land is not subject to depreciation. Maintenance and repairs are charged to expense as incurred, while major improvements are capitalized and amortized to operating expense over their identified useful lives. Premises and equipment and other long-lived assets are tested for impairment whenever events or changes in circumstances indicate the carrying amount of the assets may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value. Assets acquired through a business acquisition are recorded at fair value as of the acquisition date.
Other real estate owned	Other real estate owned: Other real estate owned includes real estate assets that have been received in satisfaction of debt. Other real estate owned is initially recorded at fair value less estimated selling costs, which establishes the cost basis. Subsequently, other real estate owned is carried at the lower of the cost basis or fair value less estimated selling costs. Any valuation adjustments required at the date of transfer are charged to the allowance for loan and lease losses. Subsequently, unrealized losses and realized gains and losses on sale are included in net (gain) loss recognized on other real estate owned.
Cash surrender value of life insurance	Cash surrender value of life insurance: The Company has purchased bank-owned life insurance policies on certain executives. Bank-owned life insurance is recorded at its cash surrender value. Changes in the cash surrender values are included in non-interest income.
Goodwill	Goodwill : The excess of the cost of an acquisition over the fair value of the net assets acquired, including core deposit and client relationship intangibles, consists of goodwill. Under the provisions of ASC Topic 350, goodwill is subject to at least annual assessments for impairment by applying a fair value based test. The Company reviews goodwill and other intangible assets to determine potential impairment annually, or more frequently if events and circumstances indicate that the asset might be impaired, by comparing the carrying value of the asset with the anticipated future cash flows. The Company's annual assessment is done as of December 31 at the reporting unit level. The Company currently has three reporting units: Banking, Leasing and Mortgage Banking.
Other intangibles	Other intangibles : The Company’s other intangible assets consist of core deposit and customer intangibles obtained through acquisitions. Core deposit intangibles (the portion of an acquisition purchase price which represents value assigned to the existing deposit base) have finite lives and are amortized by a 150% declining balance method over four to 20 years. Other intangible assets are tested for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable from future undiscounted cash flows. If impaired, the assets are recorded at fair value.
Mortgage Servicing Rights	Mortgage Servicing Rights : The Company originates and sells residential mortgage loans in the secondary market and may retain the right to service the loans sold. Servicing involves the collection of payments from individual borrowers and the distribution of those payments to the investors. Upon a sale of mortgage loans for which servicing rights are retained, the retained mortgage servicing rights asset is capitalized at the fair value of future net cash flows expected to be realized for performing servicing activities. Purchased mortgage servicing rights are recorded at the purchase price at the date of purchase and at fair value thereafter. Mortgage servicing rights do not trade in an active market with readily observable prices. The Company determines the fair value of mortgage servicing rights by estimating the fair value of the future cash flows associated with the mortgage loans being serviced. Key economic assumptions used in measuring the fair value of mortgage servicing rights include, but are not limited to, prepayment speeds, discount rates, delinquencies and cost to service. The assumptions used in the valuation model are validated on a periodic basis. The fair value is validated on a quarterly basis with an independent third party. The Company has elected to account for mortgage servicing rights using the fair value option. Changes in the fair value are recognized in mortgage banking revenue on the Company's Consolidated Statements of Operations.
FDIC indemnification asset	FDIC indemnification asset : As part of the Heritage Community Bank ("Heritage"), Benchmark Bank ("Benchmark"), Broadway Bank ("Broadway"), and New Century Bank ("New Century") FDIC-assisted transactions, MB Financial Bank entered into loss-share agreements with the FDIC. These agreements cover realized losses on loans and foreclosed real estate for specified periods. See Note 5 below for more information on these agreements, including the duration of MB Financial Bank’s loss-share coverage. These loss-share assets are measured separately from the loan portfolios because they are not contractually embedded in the loans and are not transferable with the loans should MB Financial Bank choose to dispose of them. Fair values at the acquisition dates were estimated based on projected cash flows available for loss-share based on the credit adjustments estimated for each loan pool and the loss-share percentages. The loss-share assets are also separately measured from the related loans and foreclosed real estate and recorded within other assets on the balance sheet. The corresponding accretion is recorded in other income on the statement of operations. Although these assets are contractual receivables from the FDIC, there are no contractual interest rates.
Preferred stock	Preferred stock: Preferred stock issued in connection with the Taylor Capital Group, Inc. and American Chartered Bancorp, Inc. mergers was initially recorded at fair value. Preferred stock issued through an underwritten public offering was recorded at the liquidation preference less underwriting discounts and other allowable costs. Preferred dividends declared are deducted from net income for computing net income available to common stockholders and earnings per common share computations.
Treasury stock	Treasury stock: Treasury stock is recorded at acquisition cost. Gains and losses on disposition are recorded as increases or decreases to additional paid-in capital with losses in excess of previously recorded gains charged directly to retained earnings.
Derivative financial instruments and hedging activities	Derivative financial instruments and hedging activities : ASC Topic 815 establishes accounting and reporting standards requiring that every derivative instrument (including certain derivative instruments embedded in other contracts) be recorded in the balance sheet as either an asset or liability measured at its fair value. ASC Topic 815 requires that changes in the derivative’s fair value be recognized currently in earnings unless specific hedge accounting criteria are met. Accounting for qualifying hedges allows a derivative’s gains and losses to offset related results on the hedged item in the statement of operations, and requires that a company formally document, designate and assess the effectiveness of transactions that receive hedge accounting. All derivatives are recognized on the consolidated balance sheet at their fair value. On the date the derivative contract is entered into, the Company designates the derivative as either a fair value hedge (i.e. a hedge of the fair value of a recognized asset or liability), a cash flow hedge (i.e. a hedge of the variability of cash flows to be received or paid related to a recognized asset or liability), or a non-designated derivative (i.e. an instrument with no hedging designation). For a derivative designated as a fair value hedge, the changes in the fair value of the derivative and of the hedged item attributable to the hedged risk are recognized in earnings. If the derivative is designated as a cash flow hedge, the effective portions of changes in the fair value of the derivative are recorded in other comprehensive income and are recognized in the statement of operations when the hedged item affects earnings. Ineffective portions of changes in the fair value of cash flow hedges are recognized in earnings. Changes in the fair value of derivatives that are not designated as fair value or cash flow are reported currently in earnings, as noninterest income. The Company formally documents all relationships between hedging instruments and hedging items, as well as its risk management objective and strategy for undertaking various hedge transactions. This process includes linking all derivatives that are designated as fair value hedges or cash flow hedges to specific assets or liabilities on the balance sheet. The Company also formally assesses, both at the hedge’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in fair values or cash flows of hedged items. The Company discontinues hedge accounting prospectively when it is determined that the derivative is no longer effective in offsetting changes in the fair value or cash flows of the hedged item; the derivative expires or is sold, terminated, or exercised; or management determines that designation of the derivative as a hedging instrument is no longer appropriate. When hedge accounting is discontinued because it is determined that the derivative no longer qualifies as an effective fair value hedge, the Company continues to carry the derivative on the balance sheet at its fair value, and no longer adjusts the hedged asset or liability for changes in fair value. The adjustment of the carrying amount of the hedged asset or liability is accounted for in the same manner as other components of the carrying amount of that asset or liability.
Transfers of financial assets	Transfers of financial assets : Transfers of financial assets are accounted for as sales when control over the assets has been surrendered. Control over transferred assets is deemed to be surrendered when the assets have been isolated from the Company, the transferee obtains the right (free of conditions that constrain it from taking advantage of the right) to pledge or exchange the transferred assets, and the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Sale of maintenance contracts	Sale of maintenance contracts: LaSalle Solutions, a division of MB Equipment Finance, LLC, sells third party maintenance contracts to customers. The maintenance is serviced by third party providers. Revenues are recorded net of cost of sales, as LaSalle Solutions is viewed as an agent under ASC Topic 606 - Revenue Recognition, accepting minimal credit risk, maintaining no obligation to perform maintenance under the contracts and having no control over selection of the maintenance supplier.
Asset management and trust assets	Asset management and trust assets: Assets of the asset management and trust department, other than trust cash on deposit at MB Financial Bank, are not included in these consolidated financial statements because they are not assets of the bank.
Stock-based compensation	Stock-based compensation: The Company accounts for its equity awards in accordance with ASC Topic 718 - Stock-Based Compensation. ASC Topic 718 requires companies to recognize compensation expense related to equity awards in their statement of operations. See Note 19 below for more information.
Income taxes	Income taxes: Deferred taxes are provided on a liability method whereby deferred tax assets are recognized for deductible temporary differences, operating loss carryforwards and tax credit carryforwards, while deferred tax liabilities are recognized for taxable temporary differences. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment.
Basic and diluted earnings per common share	Basic and diluted earnings per common share: Earnings per common share is computed using the two-class method. Basic earnings per common share is computed by dividing net income available to common stockholders 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, though no actual shares of common stock related to restricted stock units are issued until the settlement of such units, to the extent holders of these securities receive non-forfeitable dividends or dividend equivalents at the same rate as holders of the Company's common stock. 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.
Comprehensive income	Comprehensive income: Comprehensive income consists of net income and other comprehensive income. Other comprehensive income includes unrealized gains and losses on securities available-for-sale, net of deferred taxes, which are reported as a separate component of stockholders’ equity on the consolidated balance sheet.
Segment Reporting	Segment Reporting: An operating segment is a component of an entity that: (i) engages in business activities from which it may earn revenues and incur expenses; (ii) has operating results that are reviewed regularly by the entity’s chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance; and (iii) has discrete financial information available.
New authoritative accounting guidance	New authoritative accounting guidance: ASC Topic 805 "Business Combinations." New authoritative accounting guidance under ASC Topic 805 "Business Combinations" amends prior guidance to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 606 "Revenue from Contracts with Customers." New authoritative accounting guidance under ASC Topic 606, "Revenue from Contracts with Customers" amended prior guidance to require 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. The new authoritative guidance was initially effective for reporting periods after January 1, 2017 but was deferred to January 1, 2018. The Company's revenue is comprised of interest income on financial assets, which is excluded from the scope of this new guidance, and non-interest income. This new guidance changes how certain recurring revenue streams are recognized within lease financing revenue and insignificant components of non-interest income. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. See "Accounting changes" below. ASC Topic 825 "Financial Instruments." New authoritative accounting guidance under ASC Topic 825 "Financial Instruments" amended prior guidance to require equity investments (except those accounted for under the equity method of accounting) to be measured at fair value with changes in fair value recognized in net income. An entity may choose to measure equity investments that do not have readily determinable fair values at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. The new guidance simplifies the impairment assessment of equity investments without readily determinable fair values, requires public entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from changes in the instrument-specific credit risk when the entity has selected the fair value option for financial instruments and requires separate presentation of financial assets and liabilities by measurement category and form of financial asset. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. See "Accounting changes" below. ASC Topic 405 "Liabilities-Extinguishment of Liabilities." New authoritative accounting guidance under ASC Topic 405, "Liabilities-Extinguishment of Liabilities" amended prior guidance to clarify that liabilities related to the sale of prepaid store-value products within the scope of this guidance are financial liabilities and that breakage for those liabilities are to be accounted for consistent with the breakage guidance in ASC Topic 606 "Revenue from Contracts with Customers." The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 842 "Leases." New authoritative accounting guidance under ASC Topic 842 "Leases" amended prior guidance to require lessees to recognize the assets and liabilities arising from all leases on the balance sheet. The new authoritative guidance defines a lease as a contract, or part of a contract, that conveys the right to control the use of identified property, plant, or equipment (an identified asset) for a period of time in exchange for consideration. In addition, the qualifications for a sale and leaseback transaction have been amended. The new authoritative guidance also requires qualitative and quantitative disclosures by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The new authoritative guidance is effective for reporting periods after January 1, 2019. In July 2018, the Financial Accounting Standards Board issued new authoritative guidance to provide an additional transition method that allows entities to not apply this new guidance in the comparative periods presented in the financial statements and instead recognize a cumulative effect adjustment to the beginning retained earnings at the date of application. In December 2018, the Financial Accounting Standards Board issued new authoritative guidance requiring lessors to account for sales tax as a lessee cost and certain lessor costs excluded from the consideration of a contract that are reimbursed by the lessee as revenue. The Company expects an increase in assets and liabilities of approximately $28.9 million and $27.4 million , respectively, as a result of recording additional lease contracts where the Company is lessee and expects to adopt the new guidance prospectively as of January 1, 2019 and to not restate comparative periods. ASC Topic 815 "Derivatives and Hedging." New authoritative accounting guidance under ASC Topic 815 "Derivatives and Hedging" amended prior guidance to better align an entity's risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The new authoritative guidance expands and refines hedge accounting for both nonfinancial and financial risk components. The new authoritative guidance is effective for reporting periods after January 1, 2019. In October 2018, the Financial Accounting Standards Board issued new authoritative guidance to permit the use of the Overnight Index Swap rate based on Secured Overnight Financing Rate as a U.S. benchmark interest rate for hedge accounting purposes. This new authoritative guidance is not expected to have a significant impact on the Company's statements of operations or financial condition. ASC Topic 718 "Compensation - Stock Compensation." New authoritative accounting guidance under ASC Topic 718 "Compensation - Stock Compensation" amends prior guidance by clarifying which changes to terms or conditions of a share-based payment award require an entity to apply modification accounting. An entity should account for the effects of a modification unless the fair value, vesting conditions and classification of the modified award are the same as the original award. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 326 "Financial Instruments - Credit Losses." New authoritative accounting guidance under ASC Topic 326 " Financial Instruments - Credit Losses " amended the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information for credit loss estimates. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The new authoritative guidance also requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected (net of the allowance for credit losses). In addition, the credit losses relating to available-for-sale debt securities should be recorded through an allowance for credit losses rather than a write-down. The new authoritative guidance will be effective for reporting periods after January 1, 2020. Due to the significant differences in the new authoritative guidance from existing GAAP, the implementation of this guidance may result in material changes in our accounting for credit losses on financial instruments and will be impacted by the Company's loan and securities portfolios' composition, attributes, and quality in addition to prevailing economic conditions and forecasts at the time of adoption. As part of the Company's evaluation process, it had established a steering committee and working group, including individuals from various functional areas, to assess processes and related controls, portfolio segmentation, model development, system requirements, and needed resources, however, due to the pending merger of the Company with a subsidiary of Fifth Third Bancorp, after which the Company will become a subsidiary of Fifth Third Bancorp, the Company has changed its evaluation process to incorporate the transition of the Company's consolidated assets to Fifth Third Bancorp's consolidated assets. ASC Topic 230 "Statement of Cash Flows." New authoritative accounting guidance under ASC Topic 230 "Statement of Cash Flows" addresses eight specific cash flow classification issues with the objective of reducing the existing diversity in practice. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. New authoritative accounting guidance under ASC Topic 230 "Statement of Cash Flows" amends prior guidance to require an entity to include amounts generally described as restricted cash and restricted cash equivalents with cash and cash equivalents when reconciling the beginning of period and end of period total amounts shown on the statement of cash flows. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 740 "Income Taxes." New authoritative accounting guidance under ASC Topic 740 "Income Taxes" amends prior guidance to require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 350 "Intangibles-Goodwill and Other." New authoritative accounting guidance under ASC Topic 350 "Intangibles-Goodwill and Other" amends prior guidance to eliminate Step 2 from the goodwill impairment test and require an entity to perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The new authoritative guidance will be effective for reporting periods after January 1, 2020. The Company is evaluating the new guidance and its impact on the Company's statements of operations and financial condition. ASC Topic 610 "Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets." New authoritative accounting guidance under ASC Topic 610 "Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets" amends prior guidance to clarify the scope of Subtopic 610-20 by defining in substance nonfinancial assets and to add guidance for partial sales of nonfinancial assets. The Company adopted this new authoritative guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 310 "Receivables - Nonrefundable Fees and Other Costs." New authoritative accounting guidance under ASC Topic 310 "Receivables - Nonrefundable Fees and Other Costs" amends prior guidance by shortening the amortization period for certain callable debt securities held at a premium requiring the premium to be amortized to the earliest call date. The new authoritative guidance is effective for reporting periods after January 1, 2019. This new authoritative guidance will not have a significant impact on the Company's statements of operations or financial condition. ASC Topic 220 "Income Statement - Reporting Comprehensive Income." New authoritative accounting guidance under ASC Topic 220 "Income Statement - Reporting Comprehensive Income" allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from enactment of H.R. 1, originally known as the "Tax Cuts and Jobs Act." The new authoritative guidance will be effective for reporting periods after January 1, 2019 with early adoption permitted. The Company early adopted the new guidance on January 1, 2018, and it did not have a significant impact on the Company's statements of operations or financial condition. See "Accounting changes" below. ASC Topic 820 "Fair Value Measurement." New authoritative accounting guidance under ASC Topic 820 "Fair Value Measurement" amends prior guidance to modify the disclosure requirements. The new authoritative guidance removes the requirement to disclose the amount and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, the policy for timing of transfers between levels, the valuation processes for Level 3 fair value measurements. It also adds the requirement to disclose the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The new authoritative guidance will be effective for reporting periods after January 1, 2020 with early adoption permitted. The Company is evaluating the new guidance and its impact on the Company's statements of operations and financial condition. ASC Topic 808 "Collaborative Arrangements." New authoritative accounting guidance under ASC Topic 808 "Collaborative Arrangements" amends prior guidance by clarifying whether certain transactions between collaborative arrangement participants should be accounted for with revenue under ASC Topic 606 "Revenue from Contracts with Customers" and provides more comparability in the presentation of revenue for certain transactions between collaborative arrangement participants. The new authoritative guidance will be effective for reporting periods after January 1, 2020 with early adoption permitted. The Company is evaluating the new guidance and its impact on the Company's statements of operations and financial condition. Accounting changes . The Company adopted the new authoritative accounting guidance under ASC Topic 606, "Revenue from Contracts with Customers" on January 1, 2018 using the modified retrospective transition method for contracts that were not completed at the date of initial application. The Company recognized a cumulative effect reduction to the beginning retained earnings totaling $683 thousand . This amount relates to lease financing revenue where the Company's performance obligation is over time. Previously, such revenue was recognized immediately. See " Lease financing revenue, net " below . The new authoritative accounting guidance under ASC Topic 606 requires an entity to recognize revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. To achieve this, the Company takes the following steps: identify the contract(s) with a customer; identify the performance obligations in the contract; determine the transaction price; allocate the transaction price to the performance obligations in the contract; and recognize revenue when (or as) the Company satisfies a performance obligation. The non-interest revenue streams that are considered to be in the scope of this new guidance are discussed below. Lease financing revenue, net. Fees from the sale of third-party equipment maintenance contracts are included within lease financing revenue, net. The Company sells third-party equipment maintenance contracts and provides customers with an asset and maintenance contract management tool over the life of the maintenance contract. Since the Company provides support for the asset and maintenance contract management tool, the Company's performance obligation is satisfied over the life of the maintenance contract, and the fees are recognized monthly over the life of the maintenance contract. Payment is typically received at the time of sale of the maintenance contract. Treasury management fees and consumer and other deposit service fees. Deposit related fees (account analysis fees, monthly service fees, and other related fees) are included within treasury management fees and consumer and other deposit service fees. The Company's performance obligation is ongoing and either party may cancel at any time. These fees are generally recognized as the services are rendered on a monthly basis. Payment is typically received monthly. Wealth management fees. Wealth management fees include revenue from the management and advisement of client assets and trust administration. The Company's performance obligation is generally satisfied over time, and the fees are recognized monthly. Payment is typically received quarterly or annually. Card fees. Card fees include debit and credit card interchange fees, merchant acquiring card sponsorship fees, and ATM fees. For debit and credit card and merchant acquiring card sponsorship transactions, the Company considers the merchant as the customer for interchange revenue with the performance obligation being satisfied when the cardholder purchases goods or services from the merchant. Interchange revenue is recognized as the services are provided. The Company's performance obligation for ATM fees is satisfied when services are provided, and the fees are recognized at that time. Payment is typically received immediately or in the following month. Capital markets and international banking fees. Capital markets and international banking fees include M&A advisory and syndication fees. The Company's performance obligation is generally satisfied over time, and the fees are recognized monthly. For M&A advisory fees, a portion of the payment is received at the beginning of the engagement with the remainder received once the transaction is completed. For syndication fees, payment is received annually. The Company also adopted the new authoritative accounting guidance under ASC Topic 825 "Financial Instruments" and ASC Topic 220 "Income Statement - Reporting Comprehensive Income" on January 1, 2018. The Company recognized a cumulative effect increase to the beginning retained earnings and accumulated other comprehensive income totaling $386 thousand under ASC Topic 825 representing the fair value adjustment to equity securities at the date of initial application. In addition, the Company reclassified $729 thousand from accumulated other comprehensive loss to retained earnings for the stranded tax effects resulting from enactment of the Tax Cuts and Jobs Act at the date of initial application of the new guidance under ASC Topic 220.
Reclassifications	Reclassifications: Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Reconciliation of the Number of Shares Used in the Calculation of Basic and Diluted Earnings (Loss) Per Common Share	The following table presents a reconciliation of the number of shares used in the calculation of basic and diluted earnings per common share (amounts in thousands, except common share data): Years Ended December 31, 2018 2017 2016 Distributed earnings allocated to common stock $ 81,709 $ 69,622 $ 59,047 Undistributed earnings 132,206 234,418 115,089 Net income 213,915 304,040 174,136 Less: preferred stock dividends 12,100 8,007 8,009 Plus: return from preferred stockholders due to redemption 15,280 — — Net income available to common stockholders for basic earnings per common share 217,095 296,033 166,127 Plus: preferred stock dividends on convertible preferred stock — 7 9 Less: earnings and dividends allocated to participating securities 7 7 7 Earnings allocated to common stockholders for diluted earnings per common share $ 217,088 $ 296,033 $ 166,129 Weighted average shares outstanding for basic earnings per common share 84,277,230 83,836,732 76,968,823 Dilutive effect of: Stock options 471,954 567,855 435,976 Restricted shares and units 457,116 413,719 564,418 Convertible preferred stock — 5,150 6,904 Total dilutive effect of equity awards and convertible preferred stock 929,070 986,724 1,007,298 Weighted average shares outstanding for diluted earnings per common share 85,206,300 84,823,456 77,976,121 Basic earnings per common share $ 2.58 $ 3.53 $ 2.16 Diluted earnings per common share 2.55 3.49 2.13

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Assets Acquired and Liabilities Assumed	Estimated fair values of the assets acquired and liabilities assumed in the American Chartered Merger, as of the closing date of the transaction were as follows (in thousands): August 24, 2016 ASSETS Cash and cash equivalents $ 93,307 Investment securities available for sale 505,564 Non-marketable securities - FRB and FHLB Stock 16,000 Loans 1,942,548 Premises and equipment 39,048 Cash surrender value of life insurance 59,917 Goodwill 274,885 Other intangibles 25,452 Other real estate owned 3,960 Other assets 31,408 Total assets $ 2,992,089 LIABILITIES Deposits $ 2,389,327 Short-term borrowings 48,305 Long-term borrowings 16,000 Junior subordinated notes issued to capital trusts 28,075 Accrued expenses and other liabilities 22,966 Total liabilities $ 2,504,673 Total identifiable net assets $ 487,416 Consideration: Market value of common stock at $39.28 per share at August 24, 2016 (9,744,636 shares of common stock issued) $ 382,769 Series B preferred stock at $2,337.97 per share at August 24, 2016 (525 shares of preferred stock issued) (1) 1,227 Stock-based compensation attributed to pre-business combination service 1,103 Cash paid 102,317 Total fair value of consideration, excluding Series B preferred stock $ 487,416 (1) Per share fair value amount determined as if the shares of Series B were converted into shares common stock.
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period	The following table presents the acquired loans as of the acquisition date (in thousands): Purchased Purchased Non-Credit-Impaired Fair value $ 62,104 $ 1,880,444 Gross contractual amounts receivable 93,490 2,149,868 Best estimate of contractual cash flows not expected to be collected (1) 22,293 114,154 Best estimate of contractual cash flows expected to be collected 71,197 2,035,714 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default.
Business Acquisition, Pro Forma Information	The following table provides the unaudited pro forma information for the results of operations for the year ended December 31, 2016, as if the acquisition had occurred January 1, 2015. The pro forma results combine the historical results of American Chartered into the Company's consolidated statement of operations including the impact of certain acquisition accounting adjustments including loan discount accretion, investment securities discount accretion, intangible assets amortization, deposit premium accretion and borrowing discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2015. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The merger related expenses that have been recognized are included in net income in the table below. Year Ended December 31, 2016 (in thousands) Total revenues (net interest income plus non-interest income) $ 975,188 Net income 197,046

Investment Securities (Tables)

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Summary Investment Holdings	Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value December 31, 2018 Available for Sale U.S. Treasury securities $ 75,139 $ 2 $ — $ 75,141 U.S. Government sponsored agencies and enterprises 5,076 — (52 ) 5,024 States and political subdivisions 332,048 9,850 (421 ) 341,477 Residential mortgage-backed securities 1,414,335 3,888 (15,770 ) 1,402,453 Commercial mortgage-backed securities 31,572 80 (65 ) 31,587 Total Available for Sale 1,858,170 13,820 (16,308 ) 1,855,682 Held to Maturity States and political subdivisions 887,028 18,896 (1,079 ) 904,845 Residential mortgage-backed securities 14,656 159 — 14,815 Total Held to Maturity 901,684 19,055 (1,079 ) 919,660 Total $ 2,759,854 $ 32,875 $ (17,387 ) $ 2,775,342 December 31, 2017 Available for Sale U.S. Government sponsored agencies and enterprises $ 23,013 $ 3 $ (9 ) $ 23,007 States and political subdivisions 363,813 15,998 (486 ) 379,325 Residential mortgage-backed securities 861,594 3,035 (11,930 ) 852,699 Commercial mortgage-backed securities 71,554 612 (131 ) 72,035 Corporate bonds 70,155 84 (42 ) 70,197 Equity securities (1) 11,236 — (173 ) 11,063 Total Available for Sale 1,401,365 19,732 (12,771 ) 1,408,326 Held to Maturity States and political subdivisions 878,400 32,559 (447 ) 910,512 Residential mortgage-backed securities 80,682 1,261 — 81,943 Total Held to Maturity 959,082 33,820 (447 ) 992,455 Total $ 2,360,447 $ 53,552 $ (13,218 ) $ 2,400,781 (1) Reflected in marketable equity securities on the consolidated balance sheet following the adoption of the new guidance under ASC Topic 825 "Financial Instruments" on January 1, 2018.
Unrealized Losses on Investment Securities and the Fair Value of the Related Securities	at December 31, 2018 were as follows (in thousands): Less Than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses Available for Sale U.S. Government sponsored agencies and enterprises $ — $ — $ 5,024 $ (52 ) $ 5,024 $ (52 ) States and political subdivisions 6,725 (13 ) 23,328 (408 ) 30,053 (421 ) Residential mortgage-backed securities 465,935 (2,605 ) 517,954 (13,165 ) 983,889 (15,770 ) Commercial mortgage-backed securities 11,885 (28 ) 11,641 (37 ) 23,526 (65 ) Total Available for Sale 484,545 (2,646 ) 557,947 (13,662 ) 1,042,492 (16,308 ) Held to Maturity States and political subdivisions 70,076 (475 ) 26,333 (604 ) 96,409 (1,079 ) Total $ 554,621 $ (3,121 ) $ 584,280 $ (14,266 ) $ 1,138,901 $ (17,387 ) Unrealized losses on investment securities by length of time in a continuous unrealized loss position and the fair value of the related securities at December 31, 2017 were as follows (in thousands): Less Than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized Value Losses Value Losses Value Losses Available for Sale U.S. Government sponsored agencies and enterprises $ 5,111 $ (9 ) $ — $ — $ 5,111 $ (9 ) States and political subdivisions 9,016 (29 ) 18,754 (457 ) 27,770 (486 ) Residential mortgage-backed securities 256,769 (1,853 ) 407,224 (10,077 ) 663,993 (11,930 ) Commercial mortgage-backed securities 19,483 (20 ) 14,583 (111 ) 34,066 (131 ) Corporate bonds 7,052 (8 ) 9,963 (34 ) 17,015 (42 ) Equity securities 11,063 (173 ) — — 11,063 (173 ) Total Available for Sale 308,494 (2,092 ) 450,524 (10,679 ) 759,018 (12,771 ) Held to Maturity States and political subdivisions 45,499 (257 ) 12,561 (190 ) 58,060 (447 ) Total $ 353,993 $ (2,349 ) $ 463,085 $ (10,869 ) $ 817,078 $ (13,218 )
Summary of Realized Gains (Losses) on the Sale of Investment Securities Available for Sale	For the Years Ended December 31, 2018 2017 2016 Realized gains $ 424 $ 617 $ 614 Realized losses (680 ) (55 ) (167 ) Net (losses) gains $ (256 ) $ 562 $ 447
Schedule of Remaining Contractual Maturities of Securities Included in the Securities Portfolio	December 31, 2018 by contractual maturity are shown below. Maturities may differ from contractual maturities in mortgage-backed securities because the mortgages underlying the securities may be called or repaid without any penalties. Therefore, mortgage-backed securities are not included in the maturity categories in the following maturity summary. Amortized Fair (In thousands) Cost Value Available for sale: Due in one year or less $ 44,341 $ 44,613 Due after one year through five years 200,973 204,252 Due after five years through ten years 35,048 35,394 Due after ten years 131,901 137,383 Residential and commercial mortgage-backed securities 1,445,907 1,434,040 Total Available for Sale 1,858,170 1,855,682 Held to maturity: Due in one year or less 58,826 59,042 Due after one year through five years 153,790 158,329 Due after five years through ten years 242,049 248,276 Due after ten years 432,363 439,198 Residential mortgage-backed securities 14,656 14,815 Total Held to Maturity 901,684 919,660 Total $ 2,759,854 $ 2,775,342

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Schedule of Accounts Notes Financing Receivable	Loans consist of the following at (in thousands): December 31, 2018 2017 Commercial $ 5,169,763 $ 4,786,180 Commercial collateralized by assignment of lease payments 2,084,170 2,113,135 Commercial real estate 3,720,255 4,147,529 Residential real estate 1,397,598 1,432,458 Construction real estate 506,837 406,849 Indirect vehicle 817,108 667,928 Home equity 172,890 219,098 Other consumer 82,461 73,141 Gross loans, excluding purchased credit-impaired loans 13,951,082 13,846,318 Purchased credit-impaired loans 84,101 119,744 Total loans $ 14,035,183 $ 13,966,062
Contractual Aging of the Recorded Investment in Past Due Loans by Class of Loans	The following table presents the contractual aging of the recorded investment in past due loans by class of loans as of December 31, 2018 and 2017 (in thousands): Current 30-59 Days 60-89 Days Loans Past Due Total Total December 31, 2018 Commercial $ 5,160,023 $ 474 $ — $ 9,266 $ 9,740 $ 5,169,763 Commercial collateralized by assignment of lease payments 2,034,344 40,487 6,729 2,610 49,826 2,084,170 Commercial real estate: Health care 617,428 — — — — 617,428 Industrial 834,983 — — 2,814 2,814 837,797 Multifamily 514,234 1,925 — — 1,925 516,159 Retail 461,063 — — 1,232 1,232 462,295 Office 432,977 — — 120 120 433,097 Other 846,361 897 278 5,943 7,118 853,479 Residential real estate 1,373,677 7,155 2,103 14,663 23,921 1,397,598 Construction real estate 504,975 1,862 — — 1,862 506,837 Indirect vehicle 807,514 6,903 1,773 918 9,594 817,108 Home equity 169,801 990 179 1,920 3,089 172,890 Other consumer 82,147 134 150 30 314 82,461 Gross loans, excluding purchased credit-impaired loans 13,839,527 60,827 11,212 39,516 111,555 13,951,082 Purchased credit-impaired loans 45,710 7,463 3,988 26,940 38,391 84,101 Total loans $ 13,885,237 $ 68,290 $ 15,200 $ 66,456 $ 149,946 $ 14,035,183 Non-performing loan aging $ 27,672 $ 2,121 $ 1,062 $ 39,516 $ 42,699 $ 70,371 December 31, 2017 Commercial $ 4,769,244 $ 1,702 $ 6,926 $ 8,308 $ 16,936 $ 4,786,180 Commercial collateralized by assignment of lease payments 2,099,246 11,320 1,878 691 13,889 2,113,135 Commercial real estate: Health care 710,722 — — — — 710,722 Industrial 908,394 — — 755 755 909,149 Multifamily 601,844 688 — 732 1,420 603,264 Retail 503,224 — — 474 474 503,698 Office 453,960 — 956 1,454 2,410 456,370 Other 956,181 7,035 76 1,034 8,145 964,326 Residential real estate 1,410,473 12,359 1,907 7,719 21,985 1,432,458 Construction real estate 404,595 2,254 — — 2,254 406,849 Indirect vehicle 661,028 4,905 1,083 912 6,900 667,928 Home equity 210,831 3,161 1,073 4,033 8,267 219,098 Other consumer 72,846 202 36 57 295 73,141 Gross loans, excluding purchased credit-impaired loans 13,762,588 43,626 13,935 26,169 83,730 13,846,318 Purchased credit-impaired loans 63,937 8,749 3,997 43,061 55,807 119,744 Total loans $ 13,826,525 $ 52,375 $ 17,932 $ 69,230 $ 139,537 $ 13,966,062 Non-performing loan aging $ 36,879 $ 8,799 $ 4,961 $ 26,169 $ 39,929 $ 76,808
Recorded Investment in Nonaccrual Loans and Loans Past Due Ninety Days or More and Still Accruing by Class of Loans	The following table presents the recorded investment in non-accrual loans and loans past due ninety days or more and still accruing by class of loans, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): 2018 2017 Loans past due Loans past due Non-accrual 90 days or more and still accruing Non-accrual 90 days or more and still accruing Commercial $ 16,509 $ — $ 14,001 $ 3,500 Commercial collateralized by assignment of lease payments 1,551 2,398 490 531 Commercial real estate: Health care — — — — Industrial 2,814 — 8,807 — Multifamily 33 — 860 — Office 416 — 2,772 — Retail 1,232 — 590 — Other 6,710 — 8,016 190 Residential real estate 21,829 327 18,374 1,210 Construction real estate — — — — Indirect vehicle 4,176 — 3,019 81 Home equity 12,341 — 14,305 — Other consumer 5 30 4 58 Total $ 67,616 $ 2,755 $ 71,238 $ 5,570
Financing Receivable Credit Quality Indicators	The following tables present the risk category of loans by class of loans based on the most recent analysis performed, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): Pass Special Substandard Doubtful Total December 31, 2018 Commercial $ 4,785,792 $ 194,314 $ 189,657 $ — $ 5,169,763 Commercial collateralized by assignment of lease payments 2,055,391 22,768 6,011 — 2,084,170 Commercial real estate: Health care 462,399 48,711 106,318 — 617,428 Industrial 799,673 23,834 14,290 — 837,797 Multifamily 509,270 1,242 5,647 — 516,159 Retail 436,923 9,939 15,433 — 462,295 Office 410,122 3,119 19,856 — 433,097 Other 753,334 46,337 53,808 — 853,479 Construction real estate 504,246 2,247 344 — 506,837 Total $ 10,717,150 $ 352,511 $ 411,364 $ — $ 11,481,025 December 31, 2017 Commercial $ 4,535,111 $ 147,232 $ 103,837 $ — $ 4,786,180 Commercial collateralized by assignment of lease payments 2,095,668 7,527 9,940 — 2,113,135 Commercial real estate: Health care 640,751 33,672 36,299 — 710,722 Industrial 885,524 12,411 11,214 — 909,149 Multifamily 595,818 146 7,300 — 603,264 Retail 492,830 8,326 2,542 — 503,698 Office 452,902 696 2,772 — 456,370 Other 891,703 37,682 34,941 — 964,326 Construction real estate 406,849 — — — 406,849 Total $ 10,997,156 $ 247,692 $ 208,845 $ — $ 11,453,693
Schedule of Financing Receivable by Payment Activity	The following table presents the recorded investment in those loan classes based on payment activity, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): Performing Non-performing Total December 31, 2018 Residential real estate $ 1,375,442 $ 22,156 $ 1,397,598 Indirect vehicle 812,932 4,176 817,108 Home equity 160,549 12,341 172,890 Other consumer 82,426 35 82,461 Total $ 2,431,349 $ 38,708 $ 2,470,057 December 31, 2017 Residential real estate $ 1,412,874 $ 19,584 $ 1,432,458 Indirect vehicle 664,828 3,100 667,928 Home equity 204,793 14,305 219,098 Other consumer 73,079 62 73,141 Total $ 2,355,574 $ 37,051 $ 2,392,625
Loans Individually Evaluated for Impairment By Class of Loans	The following tables present loans individually evaluated for impairment by class of loans, excluding purchased credit-impaired loans, as of December 31, 2018 and 2017 (in thousands): December 31, 2018 Unpaid Recorded Partial Allowance for Average Interest With no related allowance recorded: Commercial $ 7,508 $ 4,729 $ 2,779 $ — $ 9,971 $ 222 Commercial collateralized by assignment of lease payments — — — — — — Commercial real estate: Health care — — — — — — Industrial 3,429 2,814 615 — 1,760 — Multifamily — — — — — — Retail — — — — — — Office — — — — — — Other — — — — 820 52 Residential real estate 3,793 3,755 38 — 2,995 — Construction real estate — — — — — — Indirect vehicle 695 395 300 — 692 41 Home equity 161 161 — — 60 — Other consumer — — — — — — With an allowance recorded: Commercial 32,078 10,576 21,502 1,612 12,993 256 Commercial collateralized by assignment of lease payments — — — — 83 — Commercial real estate: Health care — — — — 267 28 Industrial — — — — 1,590 8 Multifamily — — — — — — Retail — — — — — — Office — — — — — — Other 4,766 4,766 — 413 3,502 124 Residential real estate 18,966 17,159 1,807 1,454 18,158 32 Construction real estate — — — — — — Indirect vehicle — — — — — — Home equity 28,897 26,150 2,747 1,392 28,008 47 Other consumer — — — — — — Total $ 100,293 $ 70,505 $ 29,788 $ 4,871 $ 80,899 $ 810 December 31, 2017 Unpaid Recorded Partial Allowance for Average Interest With no related allowance recorded: Commercial $ 8,312 $ 7,771 $ 541 $ — $ 5,595 $ 95 Commercial collateralized by assignment of lease payments — — — — 301 — Commercial real estate: Health care — — — — — — Industrial — — — — 1,260 8 Multifamily — — — — 1,261 29 Retail — — — — 814 27 Office 527 527 — — 1,426 18 Other 10,597 10,597 — — 2,312 128 Residential real estate 1,950 1,912 38 — 483 — Construction real estate — — — — — — Indirect vehicle 408 202 206 — 411 26 Home equity 81 81 — — 376 — Other consumer — — — — — — With an allowance recorded: Commercial 7,418 7,418 — 2,315 7,668 277 Commercial collateralized by assignment of lease payments — — — — 126 14 Commercial real estate: Health care — — — — — — Industrial 8,339 8,317 22 2,669 3,215 171 Multifamily 568 568 — 320 426 — Retail — — — — 1,345 28 Office 2,293 2,277 16 752 636 4 Other — — — — 29 — Residential real estate 21,380 19,014 2,366 2,158 17,616 25 Construction real estate — — — — — — Indirect vehicle — — — — — — Home equity 30,762 28,286 2,476 2,200 27,982 54 Other consumer — — — — — — Total $ 92,635 $ 86,970 $ 5,665 $ 10,414 $ 73,282 $ 904
Schedule of Loans That Have Been Restructured Classified as Performing and Non-Performing	The following table presents loans that were restructured during the year ended December 31, 2018 (dollars in thousands): December 31, 2018 Number of Pre-Modification Recorded Post-Modification Recorded Charge-offs and Performing: Commercial 2 $ 69 $ 69 $ — Commercial real estate: Residential real estate 2 220 220 21 Home equity 2 128 128 7 Total 6 $ 417 $ 417 $ 28 Non-Performing: Commercial 1 $ 750 $ 750 $ — Commercial real estate: Residential real estate 21 3,525 3,525 1,216 Indirect vehicle 45 290 290 171 Home equity 7 606 606 233 Total 74 $ 5,171 $ 5,171 $ 1,620 The following table presents loans that were restructured during the year ended December 31, 2017 (dollars in thousands): December 31, 2017 Number of Pre-Modification Recorded Post-Modification Recorded Charge-offs and Performing: Commercial 5 $ 2,491 $ 2,491 $ 373 Commercial real estate: Industrial 3 3,174 3,174 — Retail 2 337 337 — Office 1 548 548 — Other 4 4,171 4,171 — Residential real estate 10 1,744 1,744 230 Home equity 5 122 122 9 Total 30 $ 12,587 $ 12,587 $ 612 Non-Performing: Commercial 6 $ 1,363 $ 1,363 $ — Commercial real estate: Multifamily 3 290 290 — Retail 1 906 906 — Other 1 554 554 — Residential real estate 35 6,428 6,428 1,733 Indirect vehicle 40 277 277 150 Home equity 5 842 842 76 Total 91 $ 10,660 $ 10,660 $ 1,959
Troubled Debt Restructuring Activity Rollforward	The following tables present the troubled debt restructurings activity during the year ended December 31, 2018 (dollars in thousands): Performing Non-performing Beginning balance $ 28,554 $ 30,836 Additions 417 5,171 Charge-offs — (3,369 ) Principal payments, net (8,382 ) (8,238 ) Removals (77 ) (168 ) Transfer to other real estate owned — — Transfers in 3,754 1,473 Transfers out (1,473 ) (3,754 ) Ending balance $ 22,793 $ 21,951
Type of Financing Receivable Modifications and Restructuring	The following table presents the type of modification for loans that have been restructured and the post-modification recorded investment during the year ended December 31, 2018 (dollars in thousands): December 31, 2018 Extended Maturity, Extended Amortization and Reduction of Interest Rate Extended Maturity and/or Amortization Extended Maturity, Extended Amortization, and Delay in Payments Delay in Payments and/or Reduction of Interest Rate Total Commercial $ — $ 750 $ 69 $ — $ 819 Residential real estate 2,472 862 — 411 3,745 Indirect vehicle — — — 290 290 Home equity 293 441 — — 734 Total $ 2,765 $ 2,053 $ 69 $ 701 $ 5,588
Activity in the Allowance for Loan Losses	Activity in the allowance for loan and lease losses was as follows (in thousands): Year Ended December 31, 2018 2017 2016 Balance at beginning of year $ 159,408 $ 141,842 $ 131,508 Provision for credit losses 47,201 21,593 19,563 Charge-offs: Commercial 30,173 2,323 2,126 Commercial collateralized by assignment of lease payments 7,997 3,397 6,740 Commercial real estate 6,396 1,466 2,851 Residential real estate 1,100 932 1,356 Construction real estate — — 593 Indirect vehicle 7,656 5,433 3,505 Home equity 1,299 1,314 1,662 Other consumer 1,321 1,707 1,778 Total charge-offs 55,942 16,572 20,611 Recoveries: Commercial 2,222 3,806 2,434 Commercial collateralized by assignment of lease payments 1,275 775 550 Commercial real estate 1,956 2,817 3,729 Residential real estate 778 724 1,210 Construction real estate 695 774 142 Indirect vehicle 3,124 2,282 1,837 Home equity 817 778 756 Other consumer 522 589 724 Total recoveries 11,389 12,545 11,382 Net charge-offs 44,553 4,027 9,229 Allowance for credit losses 162,056 159,408 141,842 Allowance for unfunded credit commitments (478 ) (1,698 ) (2,476 ) Balance at December 31, $ 161,578 $ 157,710 $ 139,366
Allowance Activity for Loan Losses by Portfolio Segment Based on Impairment Method	The following table presents the activity in the allowance for credit losses, balance in allowance for credit losses and recorded investment in loans by portfolio segment and based on impairment method as of December 31, 2018 and 2017 (in thousands): Commercial Commercial collateralized by assignment of lease payments Commercial real estate Residential real estate Construction real estate Indirect vehicle Home equity Other Consumer Unfunded Commitments Total December 31, 2018 Allowance for credit losses: Beginning balance $ 46,267 $ 13,007 $ 63,429 $ 7,012 $ 15,501 $ 4,728 $ 5,296 $ 2,470 $ 1,698 $ 159,408 Charge-offs 30,173 7,997 6,396 1,100 — 7,656 1,299 1,321 — 55,942 Recoveries 2,222 1,275 1,956 778 695 3,124 817 522 — 11,389 Provision 29,751 7,038 4,484 (1,577 ) 7,036 2,996 (1,424 ) 117 (1,220 ) 47,201 Ending balance $ 48,067 $ 13,323 $ 63,473 $ 5,113 $ 23,232 $ 3,192 $ 3,390 $ 1,788 $ 478 $ 162,056 Ending allowance balance attributable to loans: Individually evaluated for impairment $ 1,612 $ — $ 413 $ 1,454 $ — $ — $ 1,392 $ — $ 50 $ 4,921 Collectively evaluated for impairment 46,271 13,323 62,765 3,659 23,232 3,192 1,998 1,788 428 156,656 Acquired and accounted for under ASC Topic 310-30 (1) 184 — 295 — — — — — — 479 Total ending allowance balance $ 48,067 $ 13,323 $ 63,473 $ 5,113 $ 23,232 $ 3,192 $ 3,390 $ 1,788 $ 478 $ 162,056 Loans: Individually evaluated for impairment $ 15,305 $ — $ 7,580 $ 20,914 $ — $ 395 $ 26,311 $ — $ — $ 70,505 Collectively evaluated for impairment 5,154,458 2,084,170 3,712,675 1,376,684 506,837 816,713 146,579 82,461 — 13,880,577 Acquired and accounted for under ASC Topic 310-30 (1) 7,245 — 20,725 44,176 3,020 — 8,081 854 — 84,101 Total ending loans balance $ 5,177,008 $ 2,084,170 $ 3,740,980 $ 1,441,774 $ 509,857 $ 817,108 $ 180,971 $ 83,315 $ — $ 14,035,183 December 31, 2017 Allowance for credit losses: Beginning balance $ 44,661 $ 12,238 $ 51,807 $ 5,971 $ 14,758 $ 3,421 $ 4,689 $ 1,821 $ 2,476 $ 141,842 Charge-offs 2,323 3,397 1,466 932 — 5,433 1,314 1,707 — 16,572 Recoveries 3,806 775 2,817 724 774 2,282 778 589 — 12,545 Provision 123 3,391 10,271 1,249 (31 ) 4,458 1,143 1,767 (778 ) 21,593 Ending balance $ 46,267 $ 13,007 $ 63,429 $ 7,012 $ 15,501 $ 4,728 $ 5,296 $ 2,470 $ 1,698 $ 159,408 Ending allowance balance attributable to loans: Individually evaluated for impairment $ 2,315 $ — $ 3,741 $ 2,158 $ — $ — $ 2,200 $ — $ 437 $ 10,851 Collectively evaluated for impairment 43,861 13,007 58,637 4,854 15,466 4,728 3,096 2,470 1,261 147,380 Acquired and accounted for under ASC Topic 310-30 (1) 91 — 1,051 — 35 — — — — 1,177 Total ending allowance balance $ 46,267 $ 13,007 $ 63,429 $ 7,012 $ 15,501 $ 4,728 $ 5,296 $ 2,470 $ 1,698 $ 159,408 Loans: Individually evaluated for impairment $ 15,189 $ — $ 22,286 $ 20,926 $ — $ 202 $ 28,367 $ — $ — $ 86,970 Collectively evaluated for impairment 4,770,991 2,113,135 4,125,243 1,411,532 406,849 667,726 190,731 73,141 — 13,759,348 Acquired and accounted for under ASC Topic 310-30 (1) 13,667 — 25,490 63,137 5,220 — 10,559 1,671 — 119,744 Total ending loans balance $ 4,799,847 $ 2,113,135 $ 4,173,019 $ 1,495,595 $ 412,069 $ 667,928 $ 229,657 $ 74,812 $ — $ 13,966,062 (1) Loans acquired in business combinations and accounted for under ASC Topic 310-30 “Receivables — Loans and Debt Securities Acquired with Deteriorated Credit Quality.”
Changes in the Accretable Yield for Purchased Credit-Impaired Loans	Changes in the accretable yield for loans acquired and accounted for under ASC Topic 310-30 were as follows for the years ended December 31, 2018 and 2017 (in thousands): Year Ended December 31, 2018 2017 Balance at beginning of period $ 12,069 $ 16,050 Purchases — 43 Accretion (8,270 ) (12,500 ) Other (1) 2,125 8,476 Balance at end of period $ 5,924 $ 12,069 (1) Primarily includes discount transfers from non-accretable discount to accretable discount due to better than expected performance of loan pools acquired and accounted for under ASC Topic 310-30.
Purchased Loans Disclosures	Purchased Purchased Non-Credit-Impaired Total December 31, 2018 Covered loans (1) : Consumer related $ 12,071 $ — $ 12,071 Non covered loans: Commercial loans $ 7,245 $ 101,971 $ 109,216 Commercial loans collateralized by assignment of lease payments — 12,324 12,324 Commercial real estate 20,725 460,368 481,093 Construction real estate 3,020 1,587 4,607 Consumer related 4,412 197,377 201,789 Total non-covered loans 35,402 773,627 809,029 Total acquired $ 47,473 $ 773,627 $ 821,100 December 31, 2017 Covered loans (1) : Consumer related $ 14,898 $ — $ 14,898 Non covered loans: Commercial loans $ 13,667 $ 254,027 $ 267,694 Commercial loans collateralized by assignment of lease payments — 35,163 35,163 Commercial real estate 25,490 776,939 802,429 Construction real estate 5,220 5,660 10,880 Consumer related 4,720 276,023 280,743 Total non-covered loans 49,097 1,347,812 1,396,909 Total acquired $ 63,995 $ 1,347,812 $ 1,411,807 (1) Covered loans refer to loans covered under loss-sharing agreements with the FDIC. The remaining loss-share agreements were scheduled to expire between 2019 and 2020. Subsequent to December 31, 2018, the Company exited the loss-share agreements with the FDIC. See Note 25. Subsequent Events.

Lease Investments (Tables)

Lease Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Schedule of Lease Investments by Categories	Lease investments by categories follow (in thousands): December 31, 2018 2017 Direct finance leases: Minimum lease payments $ 453,014 $ 492,953 Estimated unguaranteed residual values 69,721 74,220 Less: unearned income (40,196 ) (41,311 ) Direct finance leases (1) $ 482,539 $ 525,862 Leveraged leases: Minimum lease payments $ — $ 179 Estimated unguaranteed residual values — 10 Less: unearned income — (3 ) Less: related non-recourse debt — (177 ) Leveraged leases (1) $ — $ 9 Operating leases: Equipment, at cost $ 694,416 $ 575,612 Less accumulated depreciation (206,640 ) (166,561 ) Lease investments, net $ 487,776 $ 409,051 (1) Direct finance and leveraged leases are included as commercial loans collateralized by assignment of lease payments for financial statement purposes.
Schedule of Minimum Lease Payments Receivable for the Various Categories of Leases Due	The minimum lease payments receivable for the various categories of leases are due as follows (in thousands) for the years ending December 31, Direct Finance Operating Year Leases Leases Total 2018 $ 162,997 $ 93,026 $ 256,023 2019 119,735 76,107 195,842 2020 79,863 57,168 137,031 2021 47,979 44,094 92,073 2022 27,759 28,603 56,362 Thereafter 14,681 35,638 50,319 $ 453,014 $ 334,636 $ 787,650
Schedule of Residual Values for Leases by Category in the Year the Initial Lease Term Ends	At December 31, 2018 , the following reflects the residual values for leases by category in the year the initial lease term ends (in thousands): Residual Values Direct End of initial lease term Finance Operating December 31, Leases Leases Total 2019 $ 9,419 $ 17,054 $ 26,473 2020 13,969 21,338 35,307 2021 7,243 30,966 38,209 2022 12,444 22,766 35,210 2023 8,894 21,632 30,526 Thereafter 17,752 41,339 59,091 $ 69,721 $ 155,095 $ 224,816
Income from Lease Investments	Income from lease financing, net was composed of (in thousands): Years Ended December 31, 2018 2017 2016 Rental income $ 104,889 $ 87,524 $ 69,083 Equipment maintenance contracts revenue, net of cost of sales 27,093 29,697 25,005 Vendor promotional income 16,223 13,475 11,073 Other lease related revenue 14,198 7,461 4,254 Gain on sale of lease payments and leased equipment, net of residual write downs 20,333 12,381 13,241 Income on lease investments, gross 182,736 150,538 122,656 Less: depreciation on operating leases (78,246 ) (63,951 ) (49,170 ) Lease financing, net $ 104,490 $ 86,587 $ 73,486

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Schedule of Premises and Equipment	Premises and equipment consisted of (in thousands): December 31, 2018 2017 Land and land improvements $ 76,827 $ 78,329 Buildings 116,558 116,584 Furniture and equipment 185,242 174,778 Buildings and leasehold improvements 85,692 81,589 464,319 451,280 Accumulated depreciation (193,705 ) (164,590 ) Premises and equipment, net $ 270,614 $ 286,690

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of the Carrying Amount of Goodwill	The following table presents the changes in the carrying amount of goodwill as of December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Banking Leasing Mortgage banking Total Banking Leasing Mortgage banking Total Balance at beginning of period $ 959,285 $ 40,640 $ 3,623 $ 1,003,548 $ 960,398 $ 40,640 $ — $ 1,001,038 Goodwill from business combinations — — — — (1,113 ) — 3,623 2,510 Impairment — — (3,623 ) (3,623 ) — — — — Balance at end of period $ 959,285 $ 40,640 $ — $ 999,925 $ 959,285 $ 40,640 $ 3,623 $ 1,003,548
Changes in the Carrying Amount of Core Deposit and Client Relationship Intangibles	The following table presents the changes in the carrying amount of core deposit and client relationship intangibles, gross carrying amount, accumulated amortization, and net book value as of December 31, 2018 and 2017 (in thousands): December 31, 2018 2017 Balance at beginning of period $ 54,766 $ 62,959 Amortization expense (7,852 ) (8,193 ) Balance at end of period $ 46,914 $ 54,766 Gross carrying amount $ 112,820 $ 112,820 Accumulated amortization (65,906 ) (58,054 ) Net book value $ 46,914 $ 54,766
Estimated Future Amortization Expense of Other Intangible Assets	The following presents the estimated amortization expense of other intangible assets (in thousands): Years ending December 31, Amount 2019 $ 5,903 2020 4,870 2021 4,659 2022 3,696 2023 3,483 Thereafter 24,303 $ 46,914

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Schedule of Composition of Deposits	The composition of deposits was as follows (in thousands): December 31, 2018 2017 Demand deposit accounts, non-interest bearing $ 6,152,163 $ 6,381,512 NOW and money market accounts 4,982,026 4,954,765 Savings accounts 1,191,498 1,167,810 Certificates of deposit, $250,000 or more 1,344,570 1,506,071 Other certificates of deposit 983,956 948,220 Total $ 14,654,213 $ 14,958,378
Schedule of Maturities of Time Certificates	At December 31, 2018 , the scheduled maturities of certificates of deposit were as follows (in thousands): 2019 $ 1,465,426 2020 609,146 2021 148,640 2022 82,711 2023 21,833 Thereafter 770 $ 2,328,526

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Summary of Short-Term Borrowings	Short-term borrowings were as follows as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018 2017 Weighted Average Weighted Average Cost Amount Cost Amount Customer repurchase agreements 0.80 % $ 312,239 0.27 % $ 232,789 Federal Home Loan Bank advances 2.66 750,000 1.31 625,000 Federal funds purchased 2.76 407,816 1.26 3,250 Line of credit — — — — Total 2.29 % $ 1,470,055 1.03 % $ 861,039

Long-term Borrowings (Tables)

Long-term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Borrowings	Long-term borrowings were as follows as of December 31, 2018 and 2017 (dollars in thousands): December 31, 2018 2017 Weighted Average Weighted Average Cost Amount Cost Amount Federal Home Loan Bank advances 2.85 % $ 94,147 1.73 % $ 231,317 Notes payable 4.95 82,407 4.14 90,807 Subordinated notes, net of issuance costs 4.00 173,127 4.00 173,034 Term note — — 3.31 10,000 Total 3.91 % $ 349,681 2.97 % $ 505,158
Schedule of Principal Payments Due on Long-term Borrowings	The principal payments on long-term borrowings are due as follows (in thousands): Amount Years ending December 31, 2019 $ 38,904 2020 25,242 2021 12,057 2022 5,050 2023 90,387 Thereafter 178,041 Total $ 349,681

Junior Subordinated Notes Iss_2

Junior Subordinated Notes Issued to Capital Trusts (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Outstanding Junior Subordinated Notes and the Related Trust Preferred Securities Issued by Each Trust	The table below summarizes the outstanding junior subordinated notes and the related trust preferred securities issued by each trust as of December 31, 2018 (in thousands): MB Financial Capital Trust II MB Financial Capital Trust III MB Financial Capital Trust IV Junior Subordinated Notes: Principal balance $ 36,083 $ 10,310 $ 20,619 Annual interest rate 3-mo LIBOR + 1.40% 3-mo LIBOR + 1.50% 3-mo LIBOR + 1.52% Stated maturity date September 15, 2035 September 23, 2036 September 15, 2036 Call date December 15, 2010 September 23, 2011 September 15, 2011 Trust Preferred Securities: Face Value $ 35,000 $ 10,000 $ 20,000 Annual distribution rate 3-mo LIBOR + 1.40% 3-mo LIBOR + 1.50% 3-mo LIBOR + 1.52% Issuance date August 2005 July 2006 August 2006 Distribution dates (1) Quarterly Quarterly Quarterly MB Financial Capital Trust V MB Financial Capital Trust VI Junior Subordinated Notes: Principal balance $ 30,928 $ 23,196 Annual interest rate 3-mo LIBOR + 1.30% 3-mo LIBOR + 1.30% Stated maturity date December 15, 2037 October 30, 2037 Call date December 15, 2012 October 30, 2012 Trust Preferred Securities: Face Value $ 30,000 $ 22,500 Annual distribution rate 3-mo LIBOR + 1.30% 3-mo LIBOR + 1.30% Issuance date September 2007 October 2007 Distribution dates (1) Quarterly Quarterly (1) All distributions are cumulative and paid in cash.

Lease Commitments and Rental _2

Lease Commitments and Rental Expense (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Future Minimum Annual Rental Commitments for Noncancelable Leases and Subleases	The Company leases office space for certain branch and non-bank offices. At December 31, 2018 , the future minimum annual rental commitments for these non-cancelable leases and subleases of such space were as follows (in thousands): Gross Sublease Net Years ending December 31, Rents Rents Rents 2019 $ 11,902 $ 1,276 $ 10,626 2020 8,272 532 7,740 2021 6,988 195 6,793 2022 5,452 16 5,436 2023 4,308 — 4,308 Thereafter 17,248 — 17,248 $ 54,170 $ 2,019 $ 52,151

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets and Liabilities	The deferred taxes consist of (in thousands): December 31, 2018 2017 Deferred tax asset: Allowance for credit losses $ 42,208 $ 42,560 State net operating loss carryforwards 19,495 26,981 Other real estate owned 2,182 1,905 Stock options and restricted stock 5,875 5,929 Loans 7,766 12,762 Deferred compensation 7,812 6,918 Tax credit carryforwards 13,525 40,197 Bonus accrual 8,620 2,172 Other items 311 1,797 Total deferred tax asset 107,794 141,221 Valuation allowance — — Total deferred tax asset, net of valuation allowance 107,794 141,221 Deferred tax liability: Equipment leasing (121,142 ) (127,465 ) Premises and equipment (20,856 ) (17,250 ) Mortgage servicing rights (66,749 ) (62,091 ) Deferred income from FDIC-assisted transactions (12,583 ) (20,895 ) Deferred loan costs (10,604 ) (7,555 ) Investment securities (6,876 ) (5,933 ) FHLB stock dividends (2,141 ) (2,195 ) Core deposit intangible (7,239 ) (9,023 ) Other items (4,794 ) (3,683 ) Total deferred tax liability (252,984 ) (256,090 ) Net deferred tax liability (145,190 ) (114,869 ) Net unrealized holding gain on investment securities available for sale 1,842 (959 ) Net deferred tax liability $ (143,348 ) $ (115,828 )
Schedule of Income Taxes Attributable to Continuing Operations	Income taxes attributable to continuing operations consist of (in thousands): Years Ended December 31, 2018 2017 2016 Current expense (benefit): Federal $ (4,850 ) $ 12,346 $ 26,081 State 12,290 6,994 7,204 Foreign 495 157 42 7,935 19,497 33,327 Deferred expense (benefit): Federal 31,244 (45,401 ) 37,690 State (923 ) 10,679 8,227 Foreign — — — 30,321 (34,722 ) 45,917 Income tax expense (benefit) $ 38,256 $ (15,225 ) $ 79,244
Schedule of Reconciliation Between the Statutory Federal Income Tax Rate and the Effective Tax Rate on Income From Continuing Operations	The reconciliation between the statutory federal income tax rate of 21% for 2018 and 35% for 2017 and 2016 and the effective tax rate on income from continuing operations follows (in thousands): Years Ended December 31, 2018 2017 2016 Federal income tax expense at expected statutory rate $ 52,956 $ 101,085 $ 88,683 (Decrease) increase due to: Tax exempt income, net (9,708 ) (17,164 ) (18,214 ) Tax benefit resulting from change in tax rates (13,741 ) (106,563 ) — State tax expense net of federal impact 8,980 11,487 10,030 Stock-based compensation excess tax benefits (1,597 ) (3,195 ) (2,330 ) Non-deductible contingent consideration 406 138 1,026 Non-includable increase in cash surrender value of life insurance (1,046 ) (1,889 ) (1,432 ) Non-deductible merger expense 878 — 298 Adjustment of unrecognized tax benefit (8 ) 94 1 Other items, net 1,136 782 1,182 Income tax expense $ 38,256 $ (15,225 ) $ 79,244
Schedule of Reconciliation of the Change in Unrecognized Tax Benefits	A reconciliation of the change in unrecognized tax benefits from January 1, 2018 to December 31, 2018 is as follows (in thousands): Unrecognized Tax Benefit Without Interest Interest on unrecognized Tax Benefit Total Unrecognized Tax Benefit Including Interest Balance at January 1, 2018 $ 113 $ — $ 113 Decreases related to prior year tax positions (8 ) — (8 ) Balance at December 31, 2018 $ 105 $ — $ 105

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Outstanding Financial Instruments, Contractual Amounts of Off-Balance Sheet Credit Risk	At December 31, 2018 and 2017 , the following financial instruments were outstanding, the contractual amounts of which represent off-balance sheet credit risk (in thousands): Contractual Amount 2018 2017 Commitments to extend credit: Home equity lines $ 179,521 $ 203,922 Other commitments 4,058,853 4,073,044 Letters of credit: Standby 173,755 161,014 Commercial 5,657 2,248

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Banking and Thrift [Abstract]
Schedule of the Required and Actual Amounts and Ratios for the Company and its Subsidiary Bank	The required and actual amounts and ratios for the Company and its bank subsidiary are presented below as of the dates indicated (dollars in thousands): To Be Well Capitalized Under For Capital Prompt Corrective Actual Adequacy Purposes Action Provisions Amount Ratio Amount Ratio Amount Ratio As of December 31, 2018 Total capital (to risk-weighted assets): Consolidated $ 2,379,813 13.67 % $ 1,392,791 8.00 % N/A N/A MB Financial Bank 2,264,296 13.05 1,388,457 8.00 $ 1,735,571 10.00 % Tier 1 capital (to risk-weighted assets): Consolidated $ 1,959,413 11.25 % 1,044,593 6.00 % N/A N/A MB Financial Bank 1,927,240 11.10 1,041,343 6.00 1,388,457 8.00 % Common equity tier 1 capital (to risk-weighted assets): Consolidated $ 1,764,694 10.14 % 783,445 4.50 % N/A N/A MB Financial Bank 1,925,076 11.09 781,007 4.50 1,128,121 6.50 % Tier 1 capital (to average assets): Consolidated $ 1,959,413 10.50 % 746,268 4.00 % N/A N/A MB Financial Bank 1,927,240 10.35 744,676 4.00 930,845 5.00 % As of December 31, 2017 Total capital (to risk-weighted assets): Consolidated $ 2,428,301 14.23 % $ 1,364,733 8.00 % N/A N/A MB Financial Bank 2,217,547 13.03 1,361,855 8.00 $ 1,702,318 10.00 % Tier 1 capital (to risk-weighted assets): Consolidated 1,910,336 11.20 % 1,023,550 6.00 % N/A N/A MB Financial Bank 1,883,140 11.06 1,021,391 6.00 1,361,855 8.00 % Common equity tier 1 capital (to risk-weighted assets): Consolidated 1,603,479 9.40 % 767,662 4.50 % N/A N/A MB Financial Bank 1,883,140 11.06 766,043 4.50 1,106,507 6.50 % Tier 1 capital (to average assets): Consolidated 1,910,336 10.02 % 762,370 4.00 % N/A N/A MB Financial Bank 1,883,140 9.90 760,797 4.00 950,996 5.00 % N/A — not applicable

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Financial Assets and Financial Liabilities Measured at Fair Value on a Recurring Basis	The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2018 and 2017 , segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) 2018 Financial assets Securities available for sale: U.S. Treasury securities $ 75,141 $ 75,141 $ — $ — U.S. Government sponsored agencies and enterprises 5,024 — 5,024 — States and political subdivisions 341,477 — 341,195 282 Residential mortgage-backed securities 1,402,453 — 1,402,453 — Commercial mortgage-backed securities 31,587 — 31,587 — Corporate bonds — — — — Marketable equity securities 11,075 11,075 — — Loans held for sale 45,550 — 45,550 — Loans 42,665 — 42,665 — Mortgage servicing rights 284,898 — — 284,898 Assets held in trust for deferred compensation 27,882 27,882 — — Derivative financial instruments 45,168 1,534 43,526 108 Financial liabilities Other liabilities (1) 27,882 27,882 — — Derivative financial instruments 41,300 215 41,085 — 2017 Financial assets Securities available for sale: U.S. Government sponsored agencies and enterprises $ 23,007 $ — $ 23,007 $ — States and political subdivisions 379,325 — 378,996 329 Residential mortgage-backed securities 852,699 — 852,665 34 Commercial mortgage-backed securities 72,035 — 72,035 — Corporate bonds 70,197 — 70,197 — Equity securities 11,063 11,063 — — Loans held for sale 548,578 — 548,578 — Loans 40,531 — 40,531 — Mortgage servicing rights 276,279 — — 276,279 Assets held in trust for deferred compensation 21,410 21,410 — — Derivative financial instruments 31,499 389 29,539 1,571 Financial liabilities Other liabilities (1) 21,410 21,410 — — Derivative financial instruments 40,296 1,072 39,224 — (1) Liabilities associated with assets held in trust for deferred compensation
Financial Assets Measured at Fair Value on a Recurring and Non-Recurring Basis, Unobservable Inputs Used	The following tables present additional information about the unobservable inputs used in the fair value measurement of financial and non-financial assets measured on a nonrecurring basis that were categorized within the Level 3 of the fair value hierarchy (fair value in thousands): Fair Value at Valuation December 31, 2018 Technique Unobservable Input Range Impaired loans $ 61,005 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% Foreclosed assets 11,354 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% Fair Value at Valuation December 31, 2017 Technique Unobservable Input Range Impaired loans $ 60,569 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% Foreclosed assets 15,113 Appraisal of collateral Appraisal adjustments - sales costs 5% - 10% The following tables present additional information about the unobservable inputs used in the fair value measurement of financial assets measured on a recurring basis that were categorized within the Level 3 of the fair value hierarchy (fair value in thousands): Fair Value at December 31, 2018 Valuation Technique Unobservable Input Range (in thousands) States and political subdivisions $ 282 Discounted cash flows Credit assumption 35-40% Loss Mortgage servicing rights 284,898 Discounted cash flows CPR 6.5% - 7.3% Discount rate 9.53 - 11.08 Maturity (months) 328 - 358 Delinquencies 1.92 - 4.36 Costs to service $ 67 - $ 227 Additive delinquent costs to service $ 175 - $ 1,000 Derivative financial instruments (mortgage 108 Sales cash flows Expected closing ratio 70% - 95% interest rate lock commitments) Expected delivery price 99.48 bps - 105.31 bps Fair Value at December 31, 2017 Valuation Technique Unobservable Input Range (in thousands) States and political subdivisions $ 329 Discounted cash flows Credit assumption 40-45% Loss Residential mortgage-backed securities 34 Discounted cash flows Constant pre-payment rates (CPR) 1% - 3% Mortgage servicing rights 276,279 Discounted cash flows CPR 6.7% - 7.8% Discount rate 9.53 - 11.06 Maturity (months) 324 - 358 Delinquencies 2.42 - 5.30 Costs to service $ 67 - $ 227 Additive delinquent costs to service $ 175 - $ 1,000 Derivative financial instruments (mortgage 1,571 Sales cash flows Expected closing ratio 70% - 95% interest rate lock commitments) Expected delivery price 97.38 bps - 106.87 bps
Schedule of Sensitivity Analysis of Fair Value, Transferor's interests in Transferred Financial Assets	Key economic assumptions used in the measuring of the fair value of the mortgage servicing rights and the sensitivity of the fair value to immediate adverse changes in those assumptions at December 31, 2018 are presented in the following table. This table does not take into account the derivatives used to economically hedge the mortgage servicing rights. (dollars in thousands, except for weighted average cost to service) December 31, 2018 Weighted average prepayment speed (CPR) 6.76 % Impact on fair value of 10% adverse change $ (8,462 ) Impact on fair value of 20% adverse change (16,499 ) Weighted average discount rate 9.84 % Impact on fair value of 10% adverse change $ (12,045 ) Impact on fair value of 20% adverse change (23,128 ) Weighted average delinquency rate 4.08 % Impact on fair value of 10% adverse change $ (2,591 ) Impact on fair value of 20% adverse change (4,558 ) Weighted average costs to service $ 90 Impact on fair value of 10% adverse change (5,177 ) Impact on fair value of 20% adverse change (10,355 )
Financial Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)	The following table presents additional information about financial assets measured at fair value on a recurring basis for which the Company used significant unobservable inputs (Level 3) (in thousands): Year Ended December 31, 2018 2017 2018 2017 2018 2017 Investment Securities Mortgage Servicing Rights Derivatives Balance, beginning of period $ 363 $ 544 $ 276,279 $ 238,011 $ 1,571 $ 3,160 Purchases — — 161 865 — — Originations — — 30,843 59,810 — — Included in earnings (12 ) — (22,385 ) (22,407 ) (1,463 ) (1,589 ) Principal payments (69 ) (181 ) — — — — Balance, ending of period $ 282 $ 363 $ 284,898 $ 276,279 $ 108 $ 1,571
Assets Measured at Fair Value on a Nonrecurring Basis	Assets measured at fair value on a nonrecurring basis as of December 31, 2018 and 2017 are included in the table below (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) 2018 Financial assets: Impaired loans $ 61,005 $ — $ — $ 61,005 Non-financial assets: Foreclosed assets 11,354 — — 11,354 2017 Financial assets: Impaired loans $ 60,569 $ — $ — $ 60,569 Non-financial assets: Foreclosed assets 15,113 — — 15,113
Estimated Fair Values of Financial Instruments	The estimated fair values of financial instruments are as follows (in thousands): December 31, 2018 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash and due from banks $ 503,153 $ 503,153 $ 503,153 $ — $ — Interest bearing deposits with banks 147,254 147,254 147,254 — — Investment securities available for sale 1,855,682 1,855,682 75,141 1,780,259 282 Investment securities held to maturity 901,684 919,660 — 919,660 — Marketable equity securities 11,075 11,075 11,075 — — Non-marketable securities - FHLB and FRB stock 113,957 113,957 — — 113,957 Loans held for sale 45,550 45,550 — 45,550 — Loans, net 13,873,605 13,937,096 — 42,665 13,894,431 Accrued interest receivable 68,801 68,801 68,801 — — Derivative financial instruments 45,168 45,168 1,534 43,526 108 Financial Liabilities: Non-interest bearing deposits $ 6,152,163 $ 6,152,163 $ 6,152,163 $ — $ — Interest bearing deposits 8,502,050 8,492,037 — — 8,492,037 Short-term borrowings 1,470,055 1,470,190 — — 1,470,190 Long-term borrowings 349,681 351,141 — — 351,141 Junior subordinated notes issued to capital trusts 121,118 89,321 — — 89,321 Accrued interest payable 7,216 7,216 7,216 — — Derivative financial instruments 41,300 41,300 215 41,085 — December 31, 2017 Carrying Amount Estimated Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash and due from banks $ 397,880 $ 397,880 $ 397,880 $ — $ — Interest bearing deposits with banks 181,341 181,341 181,341 — — Investment securities available for sale 1,408,326 1,408,326 11,063 1,396,900 363 Investment securities held to maturity 959,082 992,455 — 992,455 — Non-marketable securities - FHLB and FRB stock 114,111 114,111 — — 114,111 Loans held for sale 548,578 548,578 — 548,578 — Loans, net 13,808,352 13,988,392 — 40,531 13,947,861 Accrued interest receivable 63,589 63,589 63,589 — — Derivative financial instruments 31,499 31,499 389 29,539 1,571 Financial Liabilities: Non-interest bearing deposits $ 6,381,512 $ 6,381,512 $ 6,381,512 $ — $ — Interest bearing deposits 8,576,866 8,569,368 — — 8,569,368 Short-term borrowings 861,039 860,676 — — 860,676 Long-term borrowings 505,158 513,725 — — 513,725 Junior subordinated notes issued to capital trusts 211,494 170,965 — — 170,965 Accrued interest payable 6,458 6,458 6,458 — — Derivative financial instruments 40,296 40,296 1,072 39,224 —

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of the Impact of Share-Based Payment Plans in the Financial Statements	Year Ended December 31, 2018 2017 2016 Total compensation expense for share-based payment plans during the year $ 18,727 $ 17,476 $ 16,868 Amount of related income tax benefit recognized in income (1) 6,897 10,338 8,983 (1) Includes tax benefits recorded for the vesting of restricted shares and exercise of options.
Additional Information Related to Options Outstanding	The following table summarizes stock options outstanding for the year ended December 31, 2018 : Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Options outstanding as of December 31, 2017 1,721,978 $ 29.10 5.19 Granted 175,501 41.26 Exercised (493,984 ) 26.35 Expired (2,362 ) 32.99 Forfeited or cancelled (28,939 ) 31.63 Options outstanding as of December 31, 2018 1,372,194 $ 31.58 5.71 $ 12,327 Options exercisable as of December 31, 2018 887,401 $ 28.68 4.55 $ 10,137
Assumptions Used for Options Granted	The following assumptions were used for options granted during the years ended December 31, 2018 , 2017 , and 2016 : For the Years Ended December 31, 2018 2017 2016 Risk-free interest rate 2.79 % 2.18 % 1.44 % Expected volatility of Company’s stock 25.96 % 22.71 % 28.08 % Expected dividend yield 2.08 % 1.68 % 2.19 % Expected life of options (years) 5.5 5.8 5.5 Weighted average fair value per option of options granted during the year $ 9.21 $ 9.35 $ 6.66
Summary of Changes in Restricted Shares	The following is a summary of changes in restricted shares and units for the year ended December 31, 2018 : Number of Shares Weighted Average Grant Date Fair Value Shares and Units Outstanding at December 31, 2017 973,201 $ 37.03 Granted 428,752 41.65 Vested (371,640 ) 35.17 Forfeited or cancelled (114,146 ) 35.89 Shares and Units Outstanding at December 31, 2018 916,167 40.09

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Derivative Financial Instruments	The Company’s derivative financial instruments are summarized below as of December 31, 2018 and 2017 (in thousands): Asset Derivatives Liability Derivatives December 31, 2018 December 31, 2017 December 31, 2018 December 31, 2017 Notional Estimated Notional Estimated Notional Estimated Notional Estimated Amount Fair Value Amount Fair Value Amount Fair Value Amount Fair Value Derivative instruments designated as hedges of fair value: Interest rate swap contracts (1) $ — $ — $ — $ — $ 5 $ 0 $ 58 $ (1 ) Stand-alone derivative instruments: (2) Interest rate swap contracts 1,803,901 31,222 1,563,109 21,217 1,803,901 (31,222 ) 1,563,109 (21,217 ) Interest rate options contracts 465,902 2,663 372,927 1,887 465,902 (2,663 ) 372,927 (1,887 ) Foreign exchange contracts 49,327 1,393 40,713 1,934 46,845 (1,117 ) 34,029 (1,759 ) Spot foreign exchange contracts 7,026 12 1,424 23 1,628 (4 ) 24 — Mortgage banking derivatives: Interest rate swap contracts 310,000 8,235 458,000 4,479 225,000 (6,079 ) 1,008,000 (14,360 ) Treasury futures contracts 152,500 794 28,000 39 5,000 (2 ) 30,000 (222 ) TBA mortgage securities 75,000 741 15,000 16 — — 100,000 (63 ) Forward loan sale commitments — — 259,000 333 22,500 (213 ) 483,500 (787 ) Interest rate lock commitments 12,671 108 404,557 1,571 — — — — Total stand-alone derivative instruments 2,876,327 45,168 3,142,730 31,499 2,570,776 (41,300 ) 3,591,589 (40,295 ) Total $ 2,876,327 $ 45,168 $ 3,142,730 $ 31,499 $ 2,570,781 $ (41,300 ) $ 3,591,647 $ (40,296 ) (1) Derivative instruments designated to hedge fixed-rate commercial real estate loans. (2) These portfolio swaps are not designated as hedging instruments under ASC Topic 815.
Schedule of the Amount of Gains and Losses on Derivative Contracts Designated as Hedges and Not Designated as Hedges	Amounts included in other income in the consolidated statements of operations related to derivative financial instruments were as follows (in thousands): Years Ended December 31, 2018 2017 2016 Derivative instruments designated as hedges of fair value: Interest rate swap contracts $ 1 $ 3 $ 5 Stand-alone derivative instruments: Interest rate swap contracts 6,253 8,233 7,571 Interest rate options contracts — — 36 Foreign exchange contracts 612 269 970 Spot foreign exchange contracts 3,018 2,682 963 Mortgage related derivatives 454 (31,698 ) (1,509 ) Total stand-alone derivative instruments 10,337 (20,514 ) 8,031 Total $ 10,338 $ (20,511 ) $ 8,036
Schedule of Derivative Instruments	Information about the Company's financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2018 is summarized below (in thousands): Financial Assets Financial Liabilities Gross Amount Recognized Gross Amount Offset Net Amount Recognized Gross Amount Recognized Gross Amount Offset Net Amount Recognized Derivatives: Interest rate swaps, caps and floors $ 18,791 $ — $ 18,791 $ 15,098 $ — $ 15,098 Foreign exchange contracts 896 — 896 540 — 540 Mortgage related derivatives 9,771 — 9,771 6,295 — 6,295 Total derivatives 29,458 — 29,458 21,933 — 21,933 Repurchase agreements — — — 312,239 — 312,239 Total $ 29,458 $ — $ 29,458 $ 334,172 $ — $ 334,172 Financial Assets Financial Liabilities Net Amount Recognized Financial Instruments Collateral Net Amount Net Amount Recognized Financial Instruments Collateral Net Amount Derivatives: Counterparty A $ 6,046 $ (3,993 ) $ (2,053 ) $ — $ 3,993 $ (3,993 ) $ — $ — Counterparty B 1,234 (151 ) (1,083 ) — 151 (151 ) — — Counterparty C 1,660 (713 ) (947 ) — 713 (713 ) — — Other counterparties 20,518 (16,599 ) (3,741 ) 178 17,076 (16,599 ) (358 ) 119 Total derivatives 29,458 (21,456 ) (7,824 ) 178 21,933 (21,456 ) (358 ) 119 Repurchase agreements — — — — 312,239 — (312,239 ) — Total $ 29,458 $ (21,456 ) $ (7,824 ) $ 178 $ 334,172 $ (21,456 ) $ (312,597 ) $ 119 Information about the Company's financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2017 is summarized below (in thousands): Financial Assets Financial Liabilities Gross Amount Recognized Gross Amount Offset Net Amount Recognized Gross Amount Recognized Gross Amount Offset Net Amount Recognized Derivatives: Interest rate swaps, caps and floors $ 11,659 $ — $ 11,659 $ 11,562 $ — $ 11,562 Foreign exchange contracts 1,013 — 1,013 953 — 953 Mortgage related derivatives 4,868 — 4,868 15,432 — 15,432 Total derivatives 17,540 — 17,540 27,947 — 27,947 Repurchase agreements — — — 232,789 — 232,789 Total $ 17,540 $ — $ 17,540 $ 260,736 $ — $ 260,736 Financial Assets Financial Liabilities Net Amount Recognized Financial Instruments Collateral Net Amount Net Amount Recognized Financial Instruments Collateral Net Amount Derivatives: Counterparty A $ 6,068 $ (6,068 ) $ — $ — $ 13,807 $ (6,068 ) $ (7,739 ) $ — Counterparty B 3,261 (3,261 ) — — 5,595 (3,261 ) (2,334 ) — Counterparty C 5,285 (3,640 ) — 1,645 3,640 (3,640 ) — — Other counterparties 2,926 (1,750 ) — 1,176 4,905 (1,750 ) (3,150 ) 5 Total derivatives 17,540 (14,719 ) — 2,821 27,947 (14,719 ) (13,223 ) 5 Repurchase agreements — — — — 232,789 — (232,789 ) — Total $ 17,540 $ (14,719 ) $ — $ 2,821 $ 260,736 $ (14,719 ) $ (246,012 ) $ 5

Operating Segments (Tables)

Operating Segments (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, By Segment	The following tables present summary financial information for the reportable segments (in thousands): Banking Leasing Mortgage Banking Consolidated Year ended December 31, 2018 Net interest income $ 592,514 $ 9,563 $ 35,726 $ 637,803 Provision for credit losses 46,104 1,204 (107 ) 47,201 Non-interest income 179,136 100,140 63,353 342,629 Non-interest expense (1) 486,212 63,897 130,951 681,060 Income (loss) before income taxes 239,334 44,602 (31,765 ) 252,171 Income tax expense (benefit) 38,602 8,158 (8,504 ) 38,256 Net income (loss) $ 200,732 $ 36,444 $ (23,261 ) $ 213,915 Total assets $ 17,070,713 $ 1,464,380 $ 1,671,933 $ 20,207,026 Year ended December 31, 2017 Net interest income $ 550,499 $ 9,902 $ 41,976 $ 602,377 Provision for credit losses 16,555 3,858 1,180 21,593 Non-interest income 174,120 86,029 109,225 369,374 Non-interest expense (1) 462,055 57,331 141,957 661,343 Income before income taxes 246,009 34,742 8,064 288,815 Income tax expense (benefit) 65,137 (51,140 ) (29,222 ) (15,225 ) Net income $ 180,872 $ 85,882 $ 37,286 $ 304,040 Total assets $ 16,448,960 $ 1,403,690 $ 2,234,290 $ 20,086,940 Year ended December 31, 2016 Net interest income $ 475,133 $ 9,415 $ 33,343 $ 517,891 Provision for credit losses 18,583 295 685 19,563 Non-interest income 153,250 73,503 151,397 378,150 Non-interest expense (1) 421,733 48,450 152,915 623,098 Income before income taxes 188,067 34,173 31,140 253,380 Income tax expense 53,263 13,525 12,456 79,244 Net income $ 134,804 $ 20,648 $ 18,684 $ 174,136 Total assets $ 16,368,881 $ 1,224,169 $ 1,709,267 $ 19,302,317 (1) Includes merger related and repositioning expenses of $15.1 million , $9.9 million and $23.7 million in the Banking Segment for the years ended December 31, 2018 , 2017 , and 2016 , respectively, and $32.4 million in the Mortgage Banking Segment for the year ended December 31, 2018.

Condensed Parent Company Fina_2

Condensed Parent Company Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Condensed Balance Sheets	Balance Sheets (In thousands) December 31, 2018 2017 Assets Cash $ 106,808 $ 219,086 Investments in subsidiaries 2,990,651 2,961,822 Other assets 85,291 73,438 Total assets $ 3,182,750 $ 3,254,346 Liabilities and Stockholders’ Equity Short-term borrowings $ — $ — Long-term borrowings — 10,000 Junior subordinated notes issued to capital trusts 121,118 211,494 Other liabilities 26,784 23,029 Stockholders’ equity 3,034,848 3,009,823 Total liabilities and stockholders’ equity $ 3,182,750 $ 3,254,346
Condensed Statements of Operations	Statements of Operations (In thousands) Years Ended December 31, 2018 2017 2016 Dividends from subsidiaries $ 200,000 $ 78,846 $ 112,000 Interest and other income (908 ) 4,148 1,913 Interest and other expense 29,167 18,990 14,990 Income before income tax benefit and equity in undistributed net income of subsidiaries 169,925 64,004 98,923 Income tax benefit (8,045 ) (8,253 ) (5,303 ) Income before equity in undistributed net income of subsidiaries 177,970 72,257 104,226 Equity in undistributed net income of subsidiaries 35,945 231,783 69,910 Net income 213,915 304,040 174,136 Dividends on preferred shares 12,100 8,007 8,009 Return from preferred stockholders due to redemption (15,280 ) — — Net income available to common stockholders $ 217,095 $ 296,033 $ 166,127
Condensed Statements of Cash Flows	Statements of Cash Flows (In thousands) Years Ended December 31, 2018 2017 2016 Cash Flows From Operating Activities Net income $ 213,915 $ 304,040 $ 174,136 Adjustments to reconcile net income to net cash provided by operating activities: Compensation expense for share-based payment plans 18,727 17,476 16,868 Equity in undistributed net income of subsidiaries (35,945 ) (231,783 ) (69,910 ) Loss on extinguishment of debt 11,898 — — Change in other assets and other liabilities (14,172 ) 163 (28,546 ) Net cash provided by operating activities 194,423 89,896 92,548 Cash Flows From Investing Activities Investments in and advances to subsidiaries — — (2,000 ) Net cash paid in business acquisition — — (83,163 ) Net cash used in investing activities — — (85,163 ) Cash Flows From Financing Activities Treasury stock transactions, net (1,685 ) (3,271 ) (3,837 ) Stock options exercised 4,063 2,504 1,410 Dividends paid on common stock (81,883 ) (69,346 ) (58,177 ) Dividends paid on preferred stock (14,100 ) (8,007 ) (8,009 ) Issuance of preferred stock, net of issuance costs — 194,719 — Redemption of preferred stock (100,000 ) — — Net decrease short-term borrowings — (10,000 ) (15,000 ) Principal paid on long-term borrowings (10,000 ) (4,000 ) (2,000 ) Redemption of junior subordinated notes issued to capital trusts (103,096 ) — — Net cash (used in) provided by financing activities (306,701 ) 102,599 (85,613 ) Net (decrease) increase in cash (112,278 ) 192,495 (78,228 ) Cash: Beginning of year 219,086 26,591 104,819 End of year $ 106,808 $ 219,086 $ 26,591

Significant Accounting Polici_4

Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2018USD ($)Subsidiaryelementeconomic_variablereporting_unitofficesegmentcategory	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Jan. 01, 2019USD ($)	Jan. 01, 2018USD ($)
Cash and cash equivalents:
Representation and warranty reserves	$ 5,300,000	$ 7,000,000
Loans:
Number of elements in allowance for loan losses | element	3
Number of categories of commercial related loans for which a general loan loss reserve | category	4
Loan risk rating that represents those loans least likely to default	1
Loan risk rating that represents a loss	9
Period of loan risk rating migration (in years)	18 years
Number of indicators for which correlation to charge-offs is tested | economic_variable	20
Time horizon over which forecast is applied (in years)	1 year
Lease investments:
Life of leased equipment under operating leases (in years)	5 years
Goodwill:
Number of reporting units | reporting_unit	3
Other intangibles:
Number of reportable operating segments | segment	3
Goodwill impairment loss	$ 3,623,000	0	$ 0
Retained earnings	$ 1,199,485,000	1,065,303,000
Cumulative Effect of New Accounting Principle in Period of Adoption					$ (297,000)
Land Improvements
Premises and equipment:
Estimated useful lives of assets	15 years
Minimum
Loans and leases:
Period past due for discontinuance of interest accrual on loans (in days)	90 days
Troubled debt restructurings:
Period of sustained repayment for a note to get accrual status (in months)	6 months
Other intangibles:
Finite-lived intangible assets, useful life	4 years
Minimum | Computer Equipment
Premises and equipment:
Estimated useful lives of assets	3 years
Minimum | Software
Premises and equipment:
Estimated useful lives of assets	3 years
Minimum | Furniture and Equipment
Premises and equipment:
Estimated useful lives of assets	5 years
Minimum | Building and Building Improvements
Premises and equipment:
Estimated useful lives of assets	5 years
Maximum
Cash and cash equivalents:
Term of original maturity to classify instrument as cash equivalent (in days)	90 days
Loans:
Period in which external appraisal on real estate secured impaired loan was obtained (in months)	12 months
Other intangibles:
Finite-lived intangible assets, useful life	20 years
Maximum | Computer Equipment
Premises and equipment:
Estimated useful lives of assets	7 years
Maximum | Software
Premises and equipment:
Estimated useful lives of assets	7 years
Maximum | Furniture and Equipment
Premises and equipment:
Estimated useful lives of assets	10 years
Maximum | Building and Building Improvements
Premises and equipment:
Estimated useful lives of assets	39 years
MB Financial Bank
Finite-Lived Intangible Assets [Line Items]
Number of banking offices | office	86
Number of wholly owned subsidiaries | Subsidiary	2
Mortgage Banking
Other intangibles:
Goodwill impairment loss	$ 3,623,000	0
Pro Forma [Member] | Accounting Standards Update 2016-02 [Member]
Finite-Lived Intangible Assets [Line Items]
Operating Lease, Right-of-Use Asset				$ 28,900,000
Other intangibles:
Operating Lease, Liability				$ 27,400,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Other intangibles:
Retained earnings		$ (683,000)
Retained Earnings And Accumulated Other Comprehensive Income [Member] | Accounting Standards Update 2016-01 [Member]
Other intangibles:
Cumulative Effect of New Accounting Principle in Period of Adoption					386,000
Accumulated Other Comprehensive Income (Loss), Net of Tax
Other intangibles:
Cumulative Effect of New Accounting Principle in Period of Adoption					907,000
Accumulated Other Comprehensive Income (Loss), Net of Tax | Accounting Standards Update 2016-01 [Member]
Other intangibles:
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 729,000

Significant Accounting Polici_5

Significant Accounting Policies - Reconciliation of Number of Shares Used in Calculation of Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 213,915	$ 304,040	$ 174,136
Less: preferred stock dividends	12,100	8,007	8,009
Preferred Stock Redemption Discount	15,280	0	0
Net income available to common stockholders	217,095	296,033	166,127
Plus: preferred stock dividends on convertible preferred stock	0	7	9
Less: earnings and dividends allocated to participating securities	7	7	7
Earnings allocated to common stockholders for diluted earnings per common share	$ 217,088	$ 296,033	$ 166,129
Weighted average shares outstanding for basic earnings per common share (in shares)	84,277,230	83,836,732	76,968,823
Dilutive effect of:
Dilutive effect of stock options and restricted shares and units (in shares)	929,070	986,724	1,007,298
Convertible preferred stock (in shares)	0	5,150	6,904
Weighted average shares outstanding for diluted earnings per common share (in shares)	85,206,300	84,823,456	77,976,121
Basic earnings per common share (in dollars per share)	$ 2.58	$ 3.53	$ 2.16
Diluted earnings per common share (in dollars per share)	$ 2.55	$ 3.49	$ 2.13
Stock options
Dilutive effect of:
Dilutive effect of stock options and restricted shares and units (in shares)	471,954	567,855	435,976
Restricted shares and units
Dilutive effect of:
Dilutive effect of stock options and restricted shares and units (in shares)	457,116	413,719	564,418
Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Distributed earnings allocated to common stock	$ 81,709	$ 69,622	$ 59,047
Undistributed earnings	132,206	234,418	115,089
Net income	213,915	304,040	174,136
Net income available to common stockholders	$ 217,095	$ 296,033	$ 166,127
Weighted average shares outstanding for basic earnings per common share (in shares)	84,277,230	83,836,732	76,968,823
Dilutive effect of:
Weighted average shares outstanding for diluted earnings per common share (in shares)	85,206,300	84,823,456	77,976,121

Business Combinations - Narrati

Business Combinations - Narrative (Details)	Aug. 24, 2016USD ($)shares	Nov. 20, 2015USD ($)D$ / sharesshares	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Goodwill			$ 999,925,000	$ 1,003,548,000	$ 1,001,038,000
Accretable discounts for non-purchased credit-impaired loans			$ 16,585,000	$ 27,840,000	29,211,000
Series B Preferred Stock
Business Acquisition [Line Items]
Preferred stock, dividend rate (percent)		8.00%	8.00%	8.00%
American Chartered Bancorp, Inc.
Business Acquisition [Line Items]
Amount called by each warrant or right		$ 9.30
Amount paid for each fractional share (in dollars per share) | $ / shares		$ 39.01
American Chartered Bancorp, Inc. | Series D Preferred Stock
Business Acquisition [Line Items]
Preferred stock, dividend rate (percent)		8.00%
American Chartered Bancorp, Inc. | Series B Preferred Stock
Business Acquisition [Line Items]
Number of securities called by each warrant or right (in shares) | shares	1
Common Stock | American Chartered Bancorp, Inc.
Business Acquisition [Line Items]
Number of securities called by each warrant or right (in shares) | shares		0.2732
Number of trading days used to calculate share price | D		5
American Chartered Bancorp, Inc.
Business Acquisition [Line Items]
Goodwill	$ 274,885,000
Core deposit intangible	25,452,000
Identifiable net assets	487,416,000
Cash paid	102,317,000
Preferred stock and stock-based awards assumed	2,300,000
Decrease to fair value estimate of loans				$ 1,800,000
Increase to deferred tax assets					$ 733,000
Increase to goodwill				1,100,000
Business combination, merger expenses				$ 2,000,000
American Chartered Bancorp, Inc. | Purchased credit-impaired loans
Business Acquisition [Line Items]
Non-accretable difference	18,400,000
Accretable discount	5,300,000
American Chartered Bancorp, Inc. | Substandard
Business Acquisition [Line Items]
Accretable discounts for non-purchased credit-impaired loans	$ 20,700,000

Business Combinations - America

Business Combinations - American Chartered Merger Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 24, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Goodwill		$ 999,925	$ 1,003,548	$ 1,001,038
American Chartered Bancorp, Inc.
ASSETS
Cash and cash equivalents	$ 93,307
Investment securities available for sale	505,564
Non-marketable securities - FRB and FHLB Stock	16,000
Loans	1,942,548
Premises and equipment	39,048
Cash surrender value of life insurance	59,917
Goodwill	274,885
Other intangibles	25,452
Other real estate owned	3,960
Other assets	31,408
Total assets	2,992,089
LIABILITIES
Deposits	2,389,327
Short-term borrowings	48,305
Long-term borrowings and junior subordinated notes issued to capital trusts	16,000
Accrued expenses and other liabilities	22,966
Total liabilities	2,504,673
Total identifiable net assets	487,416
Consideration:
Stock-based compensation attributed to pre-business combination service	1,103
Cash paid	102,317
Total fair value of consideration, excluding Series A or Series B preferred stock	487,416
American Chartered Bancorp, Inc. | Common Stock
Consideration:
Market value of common stock and Series B preferred stock	$ 382,769
Stock issued (in dollars per share)	$ 39.28
Stock issued (in shares)	9,744,636
American Chartered Bancorp, Inc. | Preferred Stock | Series B Preferred Stock
Consideration:
Market value of common stock and Series B preferred stock	$ 1,227
Stock issued (in dollars per share)	$ 2,337.97
Stock issued (in shares)	525
American Chartered Bancorp, Inc. | Junior Subordinated Notes
LIABILITIES
Long-term borrowings and junior subordinated notes issued to capital trusts	$ 28,075

Business Combinations - Ameri_2

Business Combinations - American Chartered Merger Acquired Loans (Details) - American Chartered Bancorp, Inc. $ in Thousands	Aug. 24, 2016USD ($)
Purchased credit-impaired loans
Business Acquisition [Line Items]
Fair value	$ 62,104
Gross contractual amounts receivable	93,490
Best estimate of contractual cash flows not expected to be collected	22,293
Best estimate of contractual cash flows expected to be collected	71,197
Purchased Non-Credit-Impaired Loans
Business Acquisition [Line Items]
Fair value	1,880,444
Gross contractual amounts receivable	2,149,868
Best estimate of contractual cash flows not expected to be collected	114,154
Best estimate of contractual cash flows expected to be collected	$ 2,035,714

Business Combinations - Ameri_3

Business Combinations - American Chartered Merger Expenses Included in Net Income (Details) - American Chartered Bancorp, Inc. $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Total revenues (net interest income plus non-interest income)	$ 975,188
Net income	$ 197,046

Restrictions on Cash and Due _2

Restrictions on Cash and Due From Banks (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Required reserve balances in cash or on deposits with Federal Reserve Bank	$ 205	$ 210

Investment Securities - Amortiz

Investment Securities - Amortized Costs and Fair Values of Investment Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Available for Sale
Amortized Cost		$ 1,401,365
Gross Unrealized Gains		19,732
Gross Unrealized Losses		(12,771)
Fair Value		1,408,326
Debt Securities, Available-for-sale, Amortized Cost	$ 1,858,170
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	13,820
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(16,308)
Debt Securities, Available-for-sale	1,855,682
Held to Maturity
Amortized Cost	901,684	959,082
Gross Unrealized Gains	19,055	33,820
Gross Unrealized Losses	(1,079)	(447)
Fair Value	919,660	992,455
Total
Amortized Cost	2,759,854	2,360,447
Gross Unrealized Gains	32,875	53,552
Gross Unrealized Losses	(17,387)	(13,218)
Fair Value	2,775,342	2,400,781
US Treasury Securities [Member]
Available for Sale
Debt Securities, Available-for-sale, Amortized Cost	75,139
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	2
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0
Debt Securities, Available-for-sale	75,141
U.S. Government sponsored agencies and enterprises
Available for Sale
Amortized Cost		23,013
Gross Unrealized Gains		3
Gross Unrealized Losses		(9)
Fair Value		23,007
Debt Securities, Available-for-sale, Amortized Cost	5,076
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(52)
Debt Securities, Available-for-sale	5,024
States and political subdivisions
Available for Sale
Amortized Cost		363,813
Gross Unrealized Gains		15,998
Gross Unrealized Losses		(486)
Fair Value		379,325
Debt Securities, Available-for-sale, Amortized Cost	332,048
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	9,850
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(421)
Debt Securities, Available-for-sale	341,477
Held to Maturity
Amortized Cost	887,028	878,400
Gross Unrealized Gains	18,896	32,559
Gross Unrealized Losses	(1,079)	(447)
Fair Value	$ 904,845	910,512
Total
Percentage of securities consisting general obligation issues	95.00%
Percentage of Securities Insured	26.00%
States and political subdivisions | Securities Portfolio | Geographic Concentration Risk
Total
Percentage of investments issued by states and political subdivisions that were within the state of Illinois	20.00%
Residential mortgage-backed securities
Available for Sale
Amortized Cost		861,594
Gross Unrealized Gains		3,035
Gross Unrealized Losses		(11,930)
Fair Value		852,699
Debt Securities, Available-for-sale, Amortized Cost	$ 1,414,335
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3,888
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(15,770)
Debt Securities, Available-for-sale	1,402,453
Held to Maturity
Amortized Cost	14,656	80,682
Gross Unrealized Gains	159	1,261
Gross Unrealized Losses	0	0
Fair Value	14,815	81,943
Commercial mortgage-backed securities
Available for Sale
Amortized Cost		71,554
Gross Unrealized Gains		612
Gross Unrealized Losses		(131)
Fair Value		72,035
Debt Securities, Available-for-sale, Amortized Cost	31,572
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	80
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(65)
Debt Securities, Available-for-sale	$ 31,587
Corporate bonds
Available for Sale
Amortized Cost		70,155
Gross Unrealized Gains		84
Gross Unrealized Losses		(42)
Fair Value		70,197
Equity securities
Available for Sale
Amortized Cost		11,236
Gross Unrealized Gains		0
Gross Unrealized Losses		(173)
Fair Value		$ 11,063

Investment Securities - Unreali

Investment Securities - Unrealized Losses on Investment Securities (Details) $ in Thousands	Dec. 31, 2018USD ($)Security_Position	Dec. 31, 2017USD ($)Security_Position
Available for Sale
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (2,646)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (12,771)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		308,494
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(2,092)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	484,545
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	557,947
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(13,662)
Debt Securities, Available-for-sale, Unrealized Loss Position	1,042,492
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		450,524
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(10,679)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		759,018
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(16,308)
Total
Less Than 12 Months, Fair Value	554,621	353,993
Less Than 12 Months, Unrealized Losses	(3,121)	(2,349)
12 Months or More, Fair Value	584,280	463,085
12 Months or More, Unrealized Losses	(14,266)	(10,869)
Total Fair Value	1,138,901	817,078
Total Unrealized Losses	$ (17,387)	$ (13,218)
Number of security positions in the investment portfolio in an unrealized loss position | Security_Position	571	471
U.S. Government sponsored agencies and enterprises
Available for Sale
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ (9)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		5,111
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(9)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,024
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(52)
Debt Securities, Available-for-sale, Unrealized Loss Position	5,024
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		5,111
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(52)
States and political subdivisions
Available for Sale
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(13)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(486)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		9,016
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(29)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	6,725
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	23,328
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(408)
Debt Securities, Available-for-sale, Unrealized Loss Position	30,053
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		18,754
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(457)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		27,770
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(421)
Held to Maturity
Less Than 12 Months, Fair Value	70,076	45,499
Less than 12 Months, Unrealized Losses	(475)	(257)
12 Months or More, Fair Value	26,333	12,561
12 Months or More, Unrealized Losses	(604)	(190)
Total Fair Value	96,409	58,060
Total Unrealized Losses	(1,079)	(447)
Residential mortgage-backed securities
Available for Sale
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2,605)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(11,930)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		256,769
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(1,853)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	465,935
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	517,954
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(13,165)
Debt Securities, Available-for-sale, Unrealized Loss Position	983,889
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		407,224
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(10,077)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		663,993
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(15,770)
Commercial mortgage-backed securities
Available for Sale
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(28)
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		19,483
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(20)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	11,885
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	11,641
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(37)
Debt Securities, Available-for-sale, Unrealized Loss Position	23,526
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		14,583
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(111)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		34,066
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ (65)
Corporate bonds
Available for Sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(42)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		7,052
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(8)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		9,963
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(34)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		17,015
Equity securities
Available for Sale
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		(173)
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		11,063
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(173)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		$ 11,063

Investment Securities - Net Los

Investment Securities - Net Losses Recognized on Investment Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Available-for-sale, Realized Gain	$ 424
Debt Securities, Available-for-sale, Realized Gain (Loss)	(256)
Realized gains		$ 617	$ 614
Debt Securities, Available-for-sale, Realized Loss	$ (680)
Realized losses		(55)	(167)
Net (losses) gains		$ 562	$ 447

Investment Securities - Mortgag

Investment Securities - Mortgage-Back Securities Maturity Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amortized Cost, Available for sale
Due in one year or less	$ 44,341
Due after one year through five years	200,973
Due after five years through ten years	35,048
Due after ten years	131,901
Amortized Cost		$ 1,401,365
Debt Securities, Available-for-sale	1,855,682
Fair Value, Available for sale
Due in one year or less	44,613
Due after one year through five years	204,252
Due after five years through ten years	35,394
Due after ten years	137,383
Fair Value		1,408,326
Debt Securities, Available-for-sale, Amortized Cost	1,858,170
Amortized Cost, Held to maturity
Due in one year or less	58,826
Due after one year through five years	153,790
Due after five years through ten years	242,049
Due after ten years	432,363
Investment securities held to maturity	901,684	959,082
Fair value, Held to maturity
Due in one year or less	59,042
Due after one year through five years	158,329
Due after five years through ten years	248,276
Due after ten years	439,198
Fair Value	919,660	992,455
Total
Amortized Cost	2,759,854	2,360,447
Fair Value	2,775,342	2,400,781
Investment securities	795,500	726,100
Securities required to be pledged	694,600	625,200
Transfer of Investments From Held-To-Maturity Securities To Available-For-Sale Securities	2,610	0	$ 0
Residential and commercial mortgage-backed securities
Amortized Cost, Available for sale
Debt Securities, Available-for-sale	1,434,040
Fair Value, Available for sale
Debt Securities, Available-for-sale, Amortized Cost	1,445,907
Residential mortgage-backed securities
Amortized Cost, Available for sale
Amortized Cost		861,594
Debt Securities, Available-for-sale	1,402,453
Fair Value, Available for sale
Fair Value		852,699
Debt Securities, Available-for-sale, Amortized Cost	1,414,335
Amortized Cost, Held to maturity
Investment securities held to maturity	14,656	80,682
Fair value, Held to maturity
Fair Value	$ 14,815	$ 81,943

Loans - Schedule of Loans (Deta

Loans - Schedule of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	$ 13,951,082	$ 13,846,318
Purchased credit impaired loans	84,101	119,744
Total loans	14,035,183	13,966,062
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	5,169,763	4,786,180
Total loans	5,177,008	4,799,847
Commercial Real Estate Portfolio Segment | Commercial real estate and residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	3,720,255	4,147,529
Total loans	3,740,980	4,173,019
Commercial Real Estate Portfolio Segment | Construction real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	506,837	406,849
Total loans	509,857	412,069
Commercial Real Estate Portfolio Segment | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	853,479	964,326
Consumer Portfolio Segment | Commercial real estate and residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	1,397,598	1,432,458
Total loans	1,441,774	1,495,595
Consumer Portfolio Segment | Indirect vehicle
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	817,108	667,928
Total loans	817,108	667,928
Consumer Portfolio Segment | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	172,890	219,098
Total loans	180,971	229,657
Consumer Portfolio Segment | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	82,461	73,141
Total loans	83,315	74,812
Collateralized | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans, excluding purchased credit-impaired loans	2,084,170	2,113,135
Total loans	$ 2,084,170	$ 2,113,135

Loans - Narrative (Details)

Loans - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)category	Dec. 31, 2017USD ($)
Loans and Leases Receivable Disclosure [Line Items]
Number of highest rating categories by rating services company | category	1
Number of highest rating categories to be achieved for classification as investment grade companies | category	4
Loans outstanding to executive officers and directors	$ 40.7	$ 39.5
Advances on loans outstanding to executive officers and directors	16.5
Repayment from executive officers and directors	$ 15.4
Percentage of collateral pledge of first mortgage loans as per agreement (minimum)	160.00%
Percentage of collateral pledge of home equity loans as per agreement (minimum)	170.00%
Percentage of collateral pledge of commercial real estate loan per agreement (minimum)	157.00%
Percentage of collateral pledge of loans held for sale (minimum)	106.00%
Loans pledged as collateral for long-term Federal Home Loan Bank advances	$ 3,800	4,700
Loans required to be pledged as collateral for long-term Federal Home Loan Bank advances	3,200	3,100
Pledged Financial Instruments, Not Separately Reported, Loans Receivable, for Federal Reserve Bank Debt	771.8	902.2
Commercial Real Estate Portfolio Segment | Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans Secured By Owner-Occupied Properties	$ 1,200	$ 1,300

Loans - Aging of Recorded Inves

Loans - Aging of Recorded Investment in Past Due Loans by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total loans, excluding purchased credit impaired loans	$ 13,951,082	$ 13,846,318
Total loans	14,035,183	13,966,062
Non-performing loan aging
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	27,672	36,879
Past Due	42,699	39,929
Total loans	70,371	76,808
Purchased credit-impaired loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	45,710	63,937
Past Due	38,391	55,807
Total loans	84,101	119,744
30-59 Days Past Due | Non-performing loan aging
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,121	8,799
30-59 Days Past Due | Purchased credit-impaired loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,463	8,749
60-89 Days Past Due | Non-performing loan aging
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,062	4,961
60-89 Days Past Due | Purchased credit-impaired loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,988	3,997
Loans Past Due 90 Days or More | Non-performing loan aging
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	39,516	26,169
Loans Past Due 90 Days or More | Purchased credit-impaired loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	26,940	43,061
Gross loans, excluding purchased credit-impaired loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	13,839,527	13,762,588
Past Due	111,555	83,730
Total loans, excluding purchased credit impaired loans	13,951,082	13,846,318
Gross loans, excluding purchased credit-impaired loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	60,827	43,626
Gross loans, excluding purchased credit-impaired loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	11,212	13,935
Gross loans, excluding purchased credit-impaired loans | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	39,516	26,169
Total loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	13,885,237	13,826,525
Past Due	149,946	139,537
Total loans	14,035,183	13,966,062
Total loans | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	68,290	52,375
Total loans | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	15,200	17,932
Total loans | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	66,456	69,230
Commercial Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	5,160,023	4,769,244
Past Due	9,740	16,936
Total loans, excluding purchased credit impaired loans	5,169,763	4,786,180
Total loans	5,177,008	4,799,847
Commercial Portfolio Segment | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	474	1,702
Commercial Portfolio Segment | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	6,926
Commercial Portfolio Segment | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	9,266	8,308
Commercial Real Estate Portfolio Segment | Multifamily
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	514,234	601,844
Past Due	1,925	1,420
Total loans, excluding purchased credit impaired loans	516,159	603,264
Commercial Real Estate Portfolio Segment | Multifamily | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,925	688
Commercial Real Estate Portfolio Segment | Multifamily | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Commercial Real Estate Portfolio Segment | Multifamily | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	732
Commercial Real Estate Portfolio Segment | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	461,063	503,224
Past Due	1,232	474
Total loans, excluding purchased credit impaired loans	462,295	503,698
Commercial Real Estate Portfolio Segment | Retail | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Commercial Real Estate Portfolio Segment | Retail | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Commercial Real Estate Portfolio Segment | Retail | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,232	474
Commercial Real Estate Portfolio Segment | Office
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	432,977	453,960
Past Due	120	2,410
Total loans, excluding purchased credit impaired loans	433,097	456,370
Commercial Real Estate Portfolio Segment | Office | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Commercial Real Estate Portfolio Segment | Office | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	956
Commercial Real Estate Portfolio Segment | Office | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	120	1,454
Commercial Real Estate Portfolio Segment | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	846,361	956,181
Past Due	7,118	8,145
Total loans, excluding purchased credit impaired loans	853,479	964,326
Commercial Real Estate Portfolio Segment | Other consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	897	7,035
Commercial Real Estate Portfolio Segment | Other consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	278	76
Commercial Real Estate Portfolio Segment | Other consumer | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,943	1,034
Commercial Real Estate Portfolio Segment | Construction real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	504,975	404,595
Past Due	1,862	2,254
Total loans, excluding purchased credit impaired loans	506,837	406,849
Total loans	509,857	412,069
Commercial Real Estate Portfolio Segment | Construction real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,862	2,254
Commercial Real Estate Portfolio Segment | Construction real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Commercial Real Estate Portfolio Segment | Construction real estate | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Consumer Portfolio Segment | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	82,147	72,846
Past Due	314	295
Total loans, excluding purchased credit impaired loans	82,461	73,141
Total loans	83,315	74,812
Consumer Portfolio Segment | Other consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	134	202
Consumer Portfolio Segment | Other consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	150	36
Consumer Portfolio Segment | Other consumer | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	30	57
Consumer Portfolio Segment | Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,373,677	1,410,473
Past Due	23,921	21,985
Total loans, excluding purchased credit impaired loans	1,397,598	1,432,458
Consumer Portfolio Segment | Residential real estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,155	12,359
Consumer Portfolio Segment | Residential real estate | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,103	1,907
Consumer Portfolio Segment | Residential real estate | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	14,663	7,719
Consumer Portfolio Segment | Indirect vehicle
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	807,514	661,028
Past Due	9,594	6,900
Total loans, excluding purchased credit impaired loans	817,108	667,928
Total loans	817,108	667,928
Consumer Portfolio Segment | Indirect vehicle | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,903	4,905
Consumer Portfolio Segment | Indirect vehicle | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,773	1,083
Consumer Portfolio Segment | Indirect vehicle | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	918	912
Consumer Portfolio Segment | Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	169,801	210,831
Past Due	3,089	8,267
Total loans, excluding purchased credit impaired loans	172,890	219,098
Total loans	180,971	229,657
Consumer Portfolio Segment | Home equity | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	990	3,161
Consumer Portfolio Segment | Home equity | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	179	1,073
Consumer Portfolio Segment | Home equity | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,920	4,033
Collateralized | Commercial Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	2,034,344	2,099,246
Past Due	49,826	13,889
Total loans, excluding purchased credit impaired loans	2,084,170	2,113,135
Total loans	2,084,170	2,113,135
Collateralized | Commercial Portfolio Segment | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	40,487	11,320
Collateralized | Commercial Portfolio Segment | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,729	1,878
Collateralized | Commercial Portfolio Segment | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,610	691
Health care | Commercial Real Estate Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	617,428	710,722
Past Due	0	0
Total loans, excluding purchased credit impaired loans	617,428	710,722
Health care | Commercial Real Estate Portfolio Segment | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Health care | Commercial Real Estate Portfolio Segment | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Health care | Commercial Real Estate Portfolio Segment | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Industrial | Commercial Real Estate Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	834,983	908,394
Past Due	2,814	755
Total loans, excluding purchased credit impaired loans	837,797	909,149
Industrial | Commercial Real Estate Portfolio Segment | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Industrial | Commercial Real Estate Portfolio Segment | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	0
Industrial | Commercial Real Estate Portfolio Segment | Loans Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 2,814	$ 755

Loans - Non-Accrual Loans and L

Loans - Non-Accrual Loans and Loans Past Due (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Days or more still accruing	90 days
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Reduction in interest income associated with loans on nonaccrual status	$ 3,200	$ 2,100	$ 3,000
Total loans
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	67,616	71,238
Loans past due 90 days or more and still accruing	2,755	5,570
Commercial Portfolio Segment
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	16,509	14,001
Loans past due 90 days or more and still accruing	0	3,500
Commercial Real Estate Portfolio Segment | Multifamily
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	33	860
Loans past due 90 days or more and still accruing	0	0
Commercial Real Estate Portfolio Segment | Office
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	416	2,772
Loans past due 90 days or more and still accruing	0	0
Commercial Real Estate Portfolio Segment | Retail
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	1,232	590
Loans past due 90 days or more and still accruing	0	0
Commercial Real Estate Portfolio Segment | Other
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	6,710	8,016
Loans past due 90 days or more and still accruing	0	190
Commercial Real Estate Portfolio Segment | Construction real estate
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	0	0
Loans past due 90 days or more and still accruing	0	0
Consumer Portfolio Segment | Residential real estate
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	21,829	18,374
Loans past due 90 days or more and still accruing	327	1,210
Consumer Portfolio Segment | Indirect vehicle
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	4,176	3,019
Loans past due 90 days or more and still accruing	0	81
Consumer Portfolio Segment | Home equity
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	12,341	14,305
Loans past due 90 days or more and still accruing	0	0
Consumer Portfolio Segment | Other consumer
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	5	4
Loans past due 90 days or more and still accruing	30	58
Collateralized | Commercial Portfolio Segment
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	1,551	490
Loans past due 90 days or more and still accruing	2,398	531
Health care | Commercial Real Estate Portfolio Segment
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	0	0
Loans past due 90 days or more and still accruing	0	0
Industrial | Commercial Real Estate Portfolio Segment
Financing Receivable Recorded Investment Non Accrual and Past Due [Abstract]
Non-accrual	2,814	8,807
Loans past due 90 days or more and still accruing	$ 0	$ 0

Loans - Risk Category of Loans

Loans - Risk Category of Loans by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	$ 11,481,025	$ 11,453,693
Non-performing substandard and doubtful loans	29,300	35,600
Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	10,717,150	10,997,156
Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	352,511	247,692
Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	411,364	208,845
Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Commercial Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	5,169,763	4,786,180
Commercial Portfolio Segment | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	4,785,792	4,535,111
Commercial Portfolio Segment | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	194,314	147,232
Commercial Portfolio Segment | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	189,657	103,837
Commercial Portfolio Segment | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Commercial Real Estate Portfolio Segment | Multifamily
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	516,159	603,264
Commercial Real Estate Portfolio Segment | Multifamily | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	509,270	595,818
Commercial Real Estate Portfolio Segment | Multifamily | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	1,242	146
Commercial Real Estate Portfolio Segment | Multifamily | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	5,647	7,300
Commercial Real Estate Portfolio Segment | Multifamily | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Commercial Real Estate Portfolio Segment | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	462,295	503,698
Commercial Real Estate Portfolio Segment | Retail | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	436,923	492,830
Commercial Real Estate Portfolio Segment | Retail | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	9,939	8,326
Commercial Real Estate Portfolio Segment | Retail | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	15,433	2,542
Commercial Real Estate Portfolio Segment | Retail | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Commercial Real Estate Portfolio Segment | Office
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	433,097	456,370
Commercial Real Estate Portfolio Segment | Office | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	410,122	452,902
Commercial Real Estate Portfolio Segment | Office | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	3,119	696
Commercial Real Estate Portfolio Segment | Office | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	19,856	2,772
Commercial Real Estate Portfolio Segment | Office | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Commercial Real Estate Portfolio Segment | Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	853,479	964,326
Commercial Real Estate Portfolio Segment | Other | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	753,334	891,703
Commercial Real Estate Portfolio Segment | Other | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	46,337	37,682
Commercial Real Estate Portfolio Segment | Other | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	53,808	34,941
Commercial Real Estate Portfolio Segment | Other | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Commercial Real Estate Portfolio Segment | Construction real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	506,837	406,849
Commercial Real Estate Portfolio Segment | Construction real estate | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	504,246	406,849
Commercial Real Estate Portfolio Segment | Construction real estate | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	2,247	0
Commercial Real Estate Portfolio Segment | Construction real estate | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	344	0
Commercial Real Estate Portfolio Segment | Construction real estate | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Collateralized | Commercial Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	2,084,170	2,113,135
Collateralized | Commercial Portfolio Segment | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	2,055,391	2,095,668
Collateralized | Commercial Portfolio Segment | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	22,768	7,527
Collateralized | Commercial Portfolio Segment | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	6,011	9,940
Collateralized | Commercial Portfolio Segment | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Health care | Commercial Real Estate Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	617,428	710,722
Health care | Commercial Real Estate Portfolio Segment | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	462,399	640,751
Health care | Commercial Real Estate Portfolio Segment | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	48,711	33,672
Health care | Commercial Real Estate Portfolio Segment | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	106,318	36,299
Health care | Commercial Real Estate Portfolio Segment | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	0	0
Industrial | Commercial Real Estate Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	837,797	909,149
Industrial | Commercial Real Estate Portfolio Segment | Pass
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	799,673	885,524
Industrial | Commercial Real Estate Portfolio Segment | Special Mention
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	23,834	12,411
Industrial | Commercial Real Estate Portfolio Segment | Substandard
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	14,290	11,214
Industrial | Commercial Real Estate Portfolio Segment | Doubtful
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases receivable	$ 0	$ 0

Loans - Recorded Investment in

Loans - Recorded Investment in Loan Classes Based on Payment Activity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 11,481,025	$ 11,453,693
Amount of mortgage loans in process of foreclosure	58,800	43,600
Consumer Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	2,470,057	2,392,625
Consumer Portfolio Segment | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	2,431,349	2,355,574
Consumer Portfolio Segment | Non-performing loan aging
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	38,708	37,051
Consumer Portfolio Segment | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,397,598	1,432,458
Consumer Portfolio Segment | Residential real estate | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	1,375,442	1,412,874
Consumer Portfolio Segment | Residential real estate | Non-performing loan aging
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	22,156	19,584
Consumer Portfolio Segment | Indirect vehicle
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	817,108	667,928
Consumer Portfolio Segment | Indirect vehicle | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	812,932	664,828
Consumer Portfolio Segment | Indirect vehicle | Non-performing loan aging
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	4,176	3,100
Consumer Portfolio Segment | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	172,890	219,098
Consumer Portfolio Segment | Home equity | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	160,549	204,793
Consumer Portfolio Segment | Home equity | Non-performing loan aging
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	12,341	14,305
Consumer Portfolio Segment | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	82,461	73,141
Consumer Portfolio Segment | Other consumer | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	82,426	73,079
Consumer Portfolio Segment | Other consumer | Non-performing loan aging
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases receivable	$ 35	$ 62

Loans - Loans Individually Eval

Loans - Loans Individually Evaluated for Impairment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	$ 100,293	$ 92,635
Recorded Investment	70,505	86,970
Partial Charge-offs	29,788	5,665
Allowance for Loan and Lease Losses Allocated	4,871	10,414
Average Recorded Investment	80,899	73,282	$ 87,600
Interest Income Recognized	810	904
Interest income recognized on cash basis	810	904	$ 52
Commercial Portfolio Segment | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	7,508	8,312
Recorded Investment	4,729	7,771
Partial Charge-offs	2,779	541
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	9,971	5,595
Interest Income Recognized	222	95
Commercial Portfolio Segment | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	32,078	7,418
Recorded Investment	10,576	7,418
Partial Charge-offs	21,502	0
Allowance for Loan and Lease Losses Allocated	1,612	2,315
Average Recorded Investment	12,993	7,668
Interest Income Recognized	256	277
Commercial Real Estate Portfolio Segment | Multifamily | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	1,261
Interest Income Recognized	0	29
Commercial Real Estate Portfolio Segment | Multifamily | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	568
Recorded Investment	0	568
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	320
Average Recorded Investment	0	426
Interest Income Recognized	0	0
Commercial Real Estate Portfolio Segment | Retail | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	814
Interest Income Recognized	0	27
Commercial Real Estate Portfolio Segment | Retail | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	1,345
Interest Income Recognized	0	28
Commercial Real Estate Portfolio Segment | Office | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	527
Recorded Investment	0	527
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	1,426
Interest Income Recognized	0	18
Commercial Real Estate Portfolio Segment | Office | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	2,293
Recorded Investment	0	2,277
Partial Charge-offs	0	16
Allowance for Loan and Lease Losses Allocated	0	752
Average Recorded Investment	0	636
Interest Income Recognized	0	4
Commercial Real Estate Portfolio Segment | Other | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	10,597
Recorded Investment	0	10,597
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	820	2,312
Interest Income Recognized	52	128
Commercial Real Estate Portfolio Segment | Other | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	4,766	0
Recorded Investment	4,766	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	413	0
Average Recorded Investment	3,502	29
Interest Income Recognized	124	0
Commercial Real Estate Portfolio Segment | Construction real estate | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Commercial Real Estate Portfolio Segment | Construction real estate | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Consumer Portfolio Segment | Residential real estate | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	3,793	1,950
Recorded Investment	3,755	1,912
Partial Charge-offs	38	38
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	2,995	483
Interest Income Recognized	0	0
Consumer Portfolio Segment | Residential real estate | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	18,966	21,380
Recorded Investment	17,159	19,014
Partial Charge-offs	1,807	2,366
Allowance for Loan and Lease Losses Allocated	1,454	2,158
Average Recorded Investment	18,158	17,616
Interest Income Recognized	32	25
Consumer Portfolio Segment | Indirect vehicle | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	695	408
Recorded Investment	395	202
Partial Charge-offs	300	206
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	692	411
Interest Income Recognized	41	26
Consumer Portfolio Segment | Indirect vehicle | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Consumer Portfolio Segment | Home equity | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	161	81
Recorded Investment	161	81
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	60	376
Interest Income Recognized	0	0
Consumer Portfolio Segment | Home equity | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	28,897	30,762
Recorded Investment	26,150	28,286
Partial Charge-offs	2,747	2,476
Allowance for Loan and Lease Losses Allocated	1,392	2,200
Average Recorded Investment	28,008	27,982
Interest Income Recognized	47	54
Consumer Portfolio Segment | Consumer related | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Consumer Portfolio Segment | Consumer related | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Collateralized | Commercial Portfolio Segment | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	301
Interest Income Recognized	0	0
Collateralized | Commercial Portfolio Segment | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	83	126
Interest Income Recognized	0	14
Health care | Commercial Real Estate Portfolio Segment | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Health care | Commercial Real Estate Portfolio Segment | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	0
Recorded Investment	0	0
Partial Charge-offs	0	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	267	0
Interest Income Recognized	28	0
Industrial | Commercial Real Estate Portfolio Segment | Impaired financing receivable with no allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	3,429	0
Recorded Investment	2,814	0
Partial Charge-offs	615	0
Allowance for Loan and Lease Losses Allocated	0	0
Average Recorded Investment	1,760	1,260
Interest Income Recognized	0	8
Industrial | Commercial Real Estate Portfolio Segment | Impaired financing receivable with allowance
Loans individually evaluated for impairment by class of loans
Unpaid Principal Balance	0	8,339
Recorded Investment	0	8,317
Partial Charge-offs	0	22
Allowance for Loan and Lease Losses Allocated	0	2,669
Average Recorded Investment	1,590	3,215
Interest Income Recognized	8	171
Performing
Loans individually evaluated for impairment by class of loans
Restructured loans	22,793	28,554
Non-performing loan aging
Loans individually evaluated for impairment by class of loans
Restructured loans	$ 21,951	$ 30,836

Loans - Loans Restructured (Det

Loans - Loans Restructured (Details)	12 Months Ended
	Dec. 31, 2018USD ($)loan	Dec. 31, 2017USD ($)loan
Restructured loans
Redefaulted loans	$ 0
Period past due of recorded redefaulted loans (in days)	90 days
Performing
Restructured loans
Number of Loans | loan	6	30
Pre-Modification Recorded Investment	$ 417,000	$ 12,587,000
Post-Modification Recorded Investment	417,000	12,587,000
Charge-offs and Specific Reserves	28,000	612,000
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	28,554,000
Additions	417,000
Charge-offs	0
Principal payments, net	(8,382,000)
Removals	(77,000)
Transfer to other real estate owned	0
Transfers in	3,754,000
Transfers out	(1,473,000)
Ending balance	$ 22,793,000	$ 28,554,000
Performing | Commercial Real Estate Industrial [Member]
Restructured loans
Number of Loans | loan		3
Pre-Modification Recorded Investment		$ 3,174,000
Post-Modification Recorded Investment		3,174,000
Charge-offs and Specific Reserves		$ 0
Performing | Retail
Restructured loans
Number of Loans | loan		2
Pre-Modification Recorded Investment		$ 337,000
Post-Modification Recorded Investment		337,000
Charge-offs and Specific Reserves		$ 0
Performing | Office
Restructured loans
Number of Loans | loan		1
Pre-Modification Recorded Investment		$ 548,000
Post-Modification Recorded Investment		548,000
Charge-offs and Specific Reserves		$ 0
Performing | Other
Restructured loans
Number of Loans | loan		4
Pre-Modification Recorded Investment		$ 4,171,000
Post-Modification Recorded Investment		4,171,000
Charge-offs and Specific Reserves		$ 0
Non-performing loan aging
Restructured loans
Number of Loans | loan	74	91
Pre-Modification Recorded Investment	$ 5,171,000	$ 10,660,000
Post-Modification Recorded Investment	5,171,000	10,660,000
Charge-offs and Specific Reserves	1,620,000	1,959,000
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	30,836,000
Additions	5,171,000
Charge-offs	(3,369,000)
Principal payments, net	(8,238,000)
Removals	(168,000)
Transfer to other real estate owned	0
Transfers in	1,473,000
Transfers out	(3,754,000)
Ending balance	$ 21,951,000	$ 30,836,000
Non-performing loan aging | Retail
Restructured loans
Number of Loans | loan		1
Pre-Modification Recorded Investment		$ 906,000
Post-Modification Recorded Investment		906,000
Charge-offs and Specific Reserves		$ 0
Non-performing loan aging | Other
Restructured loans
Number of Loans | loan		1
Pre-Modification Recorded Investment		$ 554,000
Post-Modification Recorded Investment		554,000
Charge-offs and Specific Reserves		$ 0
Commercial Portfolio Segment | Performing
Restructured loans
Number of Loans | loan	2	5
Pre-Modification Recorded Investment	$ 69,000	$ 2,491,000
Post-Modification Recorded Investment	69,000	2,491,000
Charge-offs and Specific Reserves	$ 0	$ 373,000
Commercial Portfolio Segment | Non-performing loan aging
Restructured loans
Number of Loans | loan	1	6
Pre-Modification Recorded Investment	$ 750,000	$ 1,363,000
Post-Modification Recorded Investment	750,000	1,363,000
Charge-offs and Specific Reserves	$ 0	$ 0
Commercial Real Estate Portfolio Segment | Non-performing loan aging | Multifamily
Restructured loans
Number of Loans | loan		3
Pre-Modification Recorded Investment		$ 290,000
Post-Modification Recorded Investment		290,000
Charge-offs and Specific Reserves		$ 0
Consumer Portfolio Segment | Performing | Residential real estate
Restructured loans
Number of Loans | loan	2	10
Pre-Modification Recorded Investment	$ 220,000	$ 1,744,000
Post-Modification Recorded Investment	220,000	1,744,000
Charge-offs and Specific Reserves	$ 21,000	$ 230,000
Consumer Portfolio Segment | Performing | Home equity
Restructured loans
Number of Loans | loan	2	5
Pre-Modification Recorded Investment	$ 128,000	$ 122,000
Post-Modification Recorded Investment	128,000	122,000
Charge-offs and Specific Reserves	$ 7,000	$ 9,000
Consumer Portfolio Segment | Non-performing loan aging | Residential real estate
Restructured loans
Number of Loans | loan	21	35
Pre-Modification Recorded Investment	$ 3,525,000	$ 6,428,000
Post-Modification Recorded Investment	3,525,000	6,428,000
Charge-offs and Specific Reserves	$ 1,216,000	$ 1,733,000
Consumer Portfolio Segment | Non-performing loan aging | Indirect vehicle
Restructured loans
Number of Loans | loan	45	40
Pre-Modification Recorded Investment	$ 290,000	$ 277,000
Post-Modification Recorded Investment	290,000	277,000
Charge-offs and Specific Reserves	$ 171,000	$ 150,000
Consumer Portfolio Segment | Non-performing loan aging | Home equity
Restructured loans
Number of Loans | loan	7	5
Pre-Modification Recorded Investment	$ 606,000	$ 842,000
Post-Modification Recorded Investment	606,000	842,000
Charge-offs and Specific Reserves	$ 233,000	$ 76,000

Loans - Type of Modification fo

Loans - Type of Modification for Loans That Have Been Restructured (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	$ 5,588
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	819
Consumer Portfolio Segment | Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	3,745
Consumer Portfolio Segment | Indirect vehicle
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	290
Consumer Portfolio Segment | Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	734
Extended Maturity, Extended Amortization and Reduction of Interest Rate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	2,765
Extended Maturity, Extended Amortization and Reduction of Interest Rate | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Extended Maturity, Extended Amortization and Reduction of Interest Rate | Consumer Portfolio Segment | Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	2,472
Extended Maturity, Extended Amortization and Reduction of Interest Rate | Consumer Portfolio Segment | Indirect vehicle
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Extended Maturity, Extended Amortization and Reduction of Interest Rate | Consumer Portfolio Segment | Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	293
Extended Maturity and/or Amortization
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	2,053
Extended Maturity and/or Amortization | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	750
Extended Maturity and/or Amortization | Consumer Portfolio Segment | Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	862
Extended Maturity and/or Amortization | Consumer Portfolio Segment | Indirect vehicle
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Extended Maturity and/or Amortization | Consumer Portfolio Segment | Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	441
Extended Maturity, Extended Amortization, and Delay in Payments [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	69
Extended Maturity, Extended Amortization, and Delay in Payments [Member] | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	69
Extended Maturity, Extended Amortization, and Delay in Payments [Member] | Consumer Portfolio Segment | Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Extended Maturity, Extended Amortization, and Delay in Payments [Member] | Consumer Portfolio Segment | Indirect vehicle
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Extended Maturity, Extended Amortization, and Delay in Payments [Member] | Consumer Portfolio Segment | Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Delay in Payments and/or Reduction of Interest Rate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	701
Delay in Payments and/or Reduction of Interest Rate | Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	0
Delay in Payments and/or Reduction of Interest Rate | Consumer Portfolio Segment | Residential real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	411
Delay in Payments and/or Reduction of Interest Rate | Consumer Portfolio Segment | Indirect vehicle
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	290
Delay in Payments and/or Reduction of Interest Rate | Consumer Portfolio Segment | Home equity
Financing Receivable, Allowance for Credit Losses [Line Items]
Post-modification recorded investment	$ 0

Loans - Activity in Allowance f

Loans - Activity in Allowance for Loans and Lease Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year	$ 159,408	$ 141,842	$ 131,508
Provision for credit losses	47,201	21,593	19,563
Total charge-offs	55,942	16,572	20,611
Total recoveries	11,389	12,545	11,382
Net charge-offs	44,553	4,027	9,229
Allowance for credit losses	159,408	141,842	131,508	$ 162,056	$ 159,408	$ 141,842
Allowance for unfunded credit commitments				$ (478)	$ (1,698)	$ (2,476)
Ending balance	161,578	157,710	139,366
Commercial Portfolio Segment
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	30,173	2,323	2,126
Recoveries	2,222	3,806	2,434
Ending balance	48,067	46,267	44,661
Commercial Portfolio Segment | Commercial collateralized by assignment of lease payments
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	7,997	3,397	6,740
Recoveries	1,275	775	550
Commercial Real Estate Portfolio Segment | Commercial real estate and residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	6,396	1,466	2,851
Recoveries	1,956	2,817	3,729
Ending balance	63,473	63,429	51,807
Commercial Real Estate Portfolio Segment | Construction real estate
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	0	0	593
Recoveries	695	774	142
Ending balance	23,232	15,501	14,758
Consumer Portfolio Segment | Commercial real estate and residential real estate
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	1,100	932	1,356
Recoveries	778	724	1,210
Ending balance	5,113	7,012	5,971
Consumer Portfolio Segment | Indirect vehicle
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	7,656	5,433	3,505
Recoveries	3,124	2,282	1,837
Ending balance	3,192	4,728	3,421
Consumer Portfolio Segment | Home equity
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	1,299	1,314	1,662
Recoveries	817	778	756
Ending balance	3,390	5,296	4,689
Consumer Portfolio Segment | Other consumer
Allowance for Loan and Lease Losses [Roll Forward]
Charge-offs	1,321	1,707	1,778
Recoveries	$ 522	$ 589	$ 724

Loans - Allowance for Credit Lo

Loans - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Allowance for credit losses:
Beginning balance	$ 157,710	$ 139,366
Ending balance	161,578	157,710	$ 139,366
Unfunded Commitments:
Beginning balance	1,698	2,476
Allowance For Unfunded Commitments, Charge-Offs	0	0
Allowance For Unfunded Commitments, Recoveries	0	0
Provision	1,220	778
Ending balance	478	1,698	2,476
Ending allowance balance attributable to loans:
Acquired and accounted for under ASC 310-30				$ 479	$ 1,177
Total ending allowance balance	157,710	139,366	139,366	161,578	157,710
Unfunded commitments ending allowance balance:
Individually evaluated for impairment for unfunded commitments				50	437
Unfunded commitments collectively evaluated for impairment				428	1,261
Acquired and accounted for under ASC Topic 310-30				0	0
Total ending allowance balance	1,698	2,476	2,476	478	1,698
Loans:
Individually evaluated for impairment				70,505	86,970
Unfunded commitments, individually evaluated for impairment				0	0
Collectively evaluated for impairment				13,880,577	13,759,348
Unfunded commitments, collectively evaluated for impairment				0	0
Acquired and accounted for under ASC 310-30				84,101	119,744
Unfunded commitments, acquired and accounted for under ASC Topic 310-30				0	0
Total loans				14,035,183	13,966,062
Loans and Lease Receivables, Unfunded Commitment				0	0
Allowance for credit losses
Balance at beginning of year	159,408	141,842	131,508
Allowance for credit losses, Charge-offs	55,942	16,572	20,611
Allowance for credit losses, Recoveries	11,389	12,545	11,382
Allowance for credit losses, Provision	47,201	21,593
Allowance for credit losses	159,408	141,842	131,508	162,056	159,408
Allowance for credit losses ending allowance balance:
Allowance for credit losses, individually evaluated for impairment				4,921	10,851
Allowance for credit losses, collectively evaluated for impairment				156,656	147,380
Acquired and accounted for under ASC 310-30				479	1,177
Allowance for credit losses	159,408	141,842	131,508	162,056	159,408
Commercial Portfolio Segment
Allowance for credit losses:
Beginning balance	46,267	44,661
Charge-offs	30,173	2,323	2,126
Recoveries	2,222	3,806	2,434
Provision	29,751	123
Ending balance	48,067	46,267	44,661
Ending allowance balance attributable to loans:
Individually evaluated for impairment				1,612	2,315
Collectively evaluated for impairment				46,271	43,861
Acquired and accounted for under ASC 310-30				184	91
Total ending allowance balance	46,267	44,661	44,661	48,067	46,267
Loans:
Individually evaluated for impairment				15,305	15,189
Collectively evaluated for impairment				5,154,458	4,770,991
Acquired and accounted for under ASC 310-30				7,245	13,667
Total loans				5,177,008	4,799,847
Allowance for credit losses ending allowance balance:
Acquired and accounted for under ASC 310-30				184	91
Commercial Real Estate Portfolio Segment | Construction real estate
Allowance for credit losses:
Beginning balance	15,501	14,758
Charge-offs	0	0	593
Recoveries	695	774	142
Provision	7,036	(31)
Ending balance	23,232	15,501	14,758
Ending allowance balance attributable to loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				23,232	15,466
Acquired and accounted for under ASC 310-30					35
Total ending allowance balance	15,501	14,758	14,758	23,232	15,501
Loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				506,837	406,849
Acquired and accounted for under ASC 310-30				3,020	5,220
Total loans				509,857	412,069
Allowance for credit losses ending allowance balance:
Acquired and accounted for under ASC 310-30					35
Commercial Real Estate Portfolio Segment | Commercial real estate and residential real estate
Allowance for credit losses:
Beginning balance	63,429	51,807
Charge-offs	6,396	1,466	2,851
Recoveries	1,956	2,817	3,729
Provision	4,484	10,271
Ending balance	63,473	63,429	51,807
Ending allowance balance attributable to loans:
Individually evaluated for impairment				413	3,741
Collectively evaluated for impairment				62,765	58,637
Acquired and accounted for under ASC 310-30				295	1,051
Total ending allowance balance	63,429	51,807	51,807	63,473	63,429
Loans:
Individually evaluated for impairment				7,580	22,286
Collectively evaluated for impairment				3,712,675	4,125,243
Acquired and accounted for under ASC 310-30				20,725	25,490
Total loans				3,740,980	4,173,019
Allowance for credit losses ending allowance balance:
Acquired and accounted for under ASC 310-30				295	1,051
Consumer Portfolio Segment | Indirect vehicle
Allowance for credit losses:
Beginning balance	4,728	3,421
Charge-offs	7,656	5,433	3,505
Recoveries	3,124	2,282	1,837
Provision	2,996	4,458
Ending balance	3,192	4,728	3,421
Ending allowance balance attributable to loans:
Collectively evaluated for impairment				3,192	4,728
Total ending allowance balance	4,728	3,421	3,421	3,192	4,728
Loans:
Individually evaluated for impairment				395	202
Collectively evaluated for impairment				816,713	667,726
Acquired and accounted for under ASC 310-30				0	0
Total loans				817,108	667,928
Consumer Portfolio Segment | Home equity
Allowance for credit losses:
Beginning balance	5,296	4,689
Charge-offs	1,299	1,314	1,662
Recoveries	817	778	756
Provision	(1,424)	1,143
Ending balance	3,390	5,296	4,689
Ending allowance balance attributable to loans:
Individually evaluated for impairment				1,392	2,200
Collectively evaluated for impairment				1,998	3,096
Total ending allowance balance	5,296	4,689	4,689	3,390	5,296
Loans:
Individually evaluated for impairment				26,311	28,367
Collectively evaluated for impairment				146,579	190,731
Acquired and accounted for under ASC 310-30				8,081	10,559
Total loans				180,971	229,657
Consumer Portfolio Segment | Other consumer
Allowance for credit losses:
Beginning balance	2,470	1,821
Charge-offs	1,321	1,707
Recoveries	522	589
Provision	117	1,767
Ending balance	1,788	2,470	1,821
Ending allowance balance attributable to loans:
Collectively evaluated for impairment				1,788	2,470
Total ending allowance balance	2,470	1,821	1,821	1,788	2,470
Loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				82,461	73,141
Acquired and accounted for under ASC 310-30				854	1,671
Total loans				83,315	74,812
Consumer Portfolio Segment | Commercial real estate and residential real estate
Allowance for credit losses:
Beginning balance	7,012	5,971
Charge-offs	1,100	932	1,356
Recoveries	778	724	1,210
Provision	(1,577)	1,249
Ending balance	5,113	7,012	5,971
Ending allowance balance attributable to loans:
Individually evaluated for impairment				1,454	2,158
Collectively evaluated for impairment				3,659	4,854
Total ending allowance balance	7,012	5,971	5,971	5,113	7,012
Loans:
Individually evaluated for impairment				20,914	20,926
Collectively evaluated for impairment				1,376,684	1,411,532
Acquired and accounted for under ASC 310-30				44,176	63,137
Total loans				1,441,774	1,495,595
Collateralized | Commercial Portfolio Segment
Allowance for credit losses:
Beginning balance	13,007	12,238
Charge-offs	7,997	3,397
Recoveries	1,275	775
Provision	7,038	3,391
Ending balance	13,323	13,007	12,238
Ending allowance balance attributable to loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				13,323	13,007
Total ending allowance balance	$ 13,007	$ 12,238	$ 12,238	13,323	13,007
Loans:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				2,084,170	2,113,135
Acquired and accounted for under ASC 310-30				0	0
Total loans				$ 2,084,170	$ 2,113,135

Loans - Accretable Yield for Lo

Loans - Accretable Yield for Loans Acquired and Accounted for Under ASC Topic 310-30 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Changes in the accretable yield for purchased credit-impaired loans
Balance at beginning of period	$ 12,069	$ 16,050
Purchases	0	43
Accretion	(8,270)	(12,500)
Other	2,125	8,476
Balance at end of period	$ 5,924	$ 12,069

Loans - Loans Acquired Through

Loans - Loans Acquired Through Business Combination (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	$ 809,029	$ 1,396,909
Total acquired	821,100	1,411,807
Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	35,402	49,097
Total acquired	47,473	63,995
Purchased Non-Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	773,627	1,347,812
Total acquired	773,627	1,347,812
Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	109,216	267,694
Commercial Portfolio Segment | Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	7,245	13,667
Commercial Portfolio Segment | Purchased Non-Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	101,971	254,027
Commercial Real Estate Portfolio Segment | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	481,093	802,429
Commercial Real Estate Portfolio Segment | Residential real estate | Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	20,725	25,490
Commercial Real Estate Portfolio Segment | Residential real estate | Purchased Non-Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	460,368	776,939
Commercial Real Estate Portfolio Segment | Construction real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	4,607	10,880
Commercial Real Estate Portfolio Segment | Construction real estate | Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	3,020	5,220
Commercial Real Estate Portfolio Segment | Construction real estate | Purchased Non-Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	1,587	5,660
Consumer Portfolio Segment | Consumer related
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased credit impaired and covered loans	12,071	14,898
Non covered loans	201,789	280,743
Consumer Portfolio Segment | Consumer related | Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased credit impaired and covered loans	12,071	14,898
Non covered loans	4,412	4,720
Consumer Portfolio Segment | Consumer related | Purchased Non-Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased credit impaired and covered loans	0	0
Non covered loans	197,377	276,023
Collateralized | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	12,324	35,163
Collateralized | Commercial Portfolio Segment | Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	0	0
Collateralized | Commercial Portfolio Segment | Purchased Non-Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans	12,324	35,163
Other Loans Receivable | Ginnie Mae | Purchased Credit-Impaired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of purchased loans	$ 36,600	$ 55,700

Lease Investments - Lease Inves

Lease Investments - Lease Investments by Categories (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Direct finance leases:
Minimum lease payments	$ 453,014	$ 492,953
Estimated unguaranteed residual values	69,721	74,220
Less: unearned income	(40,196)	(41,311)
Direct finance leases	482,539	525,862
Leveraged leases:
Minimum lease payments	0	179
Estimated unguaranteed residual values	0	10
Less: unearned income	0	(3)
Less: related non-recourse debt	0	(177)
Leveraged leases	0	9
Operating leases:
Equipment, at cost	694,416	575,612
Less accumulated depreciation	(206,640)	(166,561)
Lease investments, net	$ 487,776	409,051
Minimum percentage of residual component in total equipment investment	10.00%
Loans at other banks for lease equipment purchases	$ 78,400	$ 76,300

Lease Investments - Minimum Lea

Lease Investments - Minimum Lease Payments Receivable (Details) $ in Thousands	Dec. 31, 2018USD ($)
Direct Finance Leases
2,019	$ 162,997
2,020	119,735
2,021	79,863
2,022	47,979
2,023	27,759
Thereafter	14,681
Total	453,014
Operating Leases
2,019	93,026
2,020	76,107
2,021	57,168
2,022	44,094
2,023	28,603
Thereafter	35,638
Total	334,636
Total
2,019	256,023
2,020	195,842
2,021	137,031
2,022	92,073
2,023	56,362
Thereafter	50,319
Total	$ 787,650

Lease Investments - Residual Va

Lease Investments - Residual Values for Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating leases rent expense net
2,018	$ 26,473
2,019	35,307
2,020	38,209
2,021	35,210
2,022	30,526
Thereafter	59,091
Total	224,816
Direct Finance Leases
Operating leases rent expense net
2,018	9,419
2,019	13,969
2,020	7,243
2,021	12,444
2,022	8,894
Thereafter	17,752
Total	69,721
Operating Leases
Operating leases rent expense net
2,018	17,054
2,019	21,338
2,020	30,966
2,021	22,766
2,022	21,632
Thereafter	41,339
Total	$ 155,095

Lease Investments - Income from

Lease Investments - Income from Lease Financing (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)lease	Dec. 31, 2017USD ($)lease	Dec. 31, 2016USD ($)
Leases [Abstract]
Number of leases | lease	4,857	4,773
Average residual value per lease	$ 46	$ 45
Average residual value per master lease	192	183
Income from Lease Financing:
Rental income	104,889	87,524	$ 69,083
Equipment maintenance contracts revenue, net of cost of sales	27,093	29,697	25,005
Vendor promotional income	16,223	13,475	11,073
Other lease related revenue	14,198	7,461	4,254
Gain on sale of lease payments and leased equipment, net of residual write downs	20,333	12,381	13,241
Income on lease investments, gross	182,736	150,538	122,656
Less: depreciation on operating leases	(78,246)	(63,951)	(49,170)
Lease financing, net	$ 104,490	$ 86,587	$ 73,486

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Premises and Equipment
Premises and equipment, gross	$ 464,319	$ 451,280
Accumulated depreciation	(193,705)	(164,590)
Premises and equipment, net	270,614	286,690
Depreciation of premises and equipment and leased equipment	32,100	29,000	$ 25,500
Land and land improvements
Premises and Equipment
Premises and equipment, gross	76,827	78,329
Buildings
Premises and Equipment
Premises and equipment, gross	116,558	116,584
Furniture and equipment
Premises and Equipment
Premises and equipment, gross	185,242	174,778
Buildings and leasehold improvements
Premises and Equipment
Premises and equipment, gross	$ 85,692	$ 81,589

Goodwill and Intangibles - Narr

Goodwill and Intangibles - Narrative (Details)	12 Months Ended
	Dec. 31, 2018USD ($)reporting_unit	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Goodwill [Line Items]
Number of reporting units | reporting_unit	3
Goodwill impairment loss	$ 3,623,000	$ 0	$ 0
Goodwill	$ 999,925,000	$ 1,003,548,000	$ 1,001,038,000
Weighted average amortization period (in years)	12 years

Goodwill and Intangibles - Carr

Goodwill and Intangibles - Carrying Amount of Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Balance at beginning of period	$ 1,003,548,000	$ 1,001,038,000
Goodwill from business combinations	0	2,510,000
Balance at end of period	999,925,000	1,003,548,000	$ 1,001,038,000
Goodwill, Impairment Loss	(3,623,000)	0	0
Banking
Goodwill [Roll Forward]
Balance at beginning of period	959,285,000	960,398,000
Goodwill from business combinations	0	(1,113,000)
Balance at end of period	959,285,000	959,285,000	960,398,000
Goodwill, Impairment Loss	0	0
Leasing
Goodwill [Roll Forward]
Balance at beginning of period	40,640,000	40,640,000
Goodwill from business combinations	0	0
Balance at end of period	40,640,000	40,640,000	40,640,000
Goodwill, Impairment Loss	0	0
Mortgage Banking
Goodwill [Roll Forward]
Balance at beginning of period	3,623,000	0
Goodwill from business combinations	0	3,623,000
Balance at end of period	0	3,623,000	$ 0
Goodwill, Impairment Loss	$ (3,623,000)	$ 0

Goodwill and Intangibles - Ca_2

Goodwill and Intangibles - Carrying Amount of Core Deposit and Client Relationship Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Finite-lived Intangible Assets [Roll Forward]
Balance at beginning of period	$ 54,766	$ 62,959
Amortization expense	(7,852)	(8,193)	$ (7,305)
Balance at end of period	46,914	54,766	62,959
Gross carrying amount				$ 112,820	$ 112,820
Accumulated amortization				(65,906)	(58,054)
Net book value	$ 54,766	$ 62,959	$ 62,959	$ 46,914	$ 54,766

Goodwill and Intangibles - Esti

Goodwill and Intangibles - Estimated Amortization Expense (Details) $ in Thousands	Dec. 31, 2018USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,019	$ 5,903
2,020	4,870
2,021	4,659
2,022	3,696
2,023	3,483
Thereafter	24,303
Intangible assets	$ 46,914

Deposits - Composition of Depos

Deposits - Composition of Deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Banking and Thrift [Abstract]
Demand deposit accounts, non-interest bearing	$ 6,152,163	$ 6,381,512
NOW and money market accounts	4,982,026	4,954,765
Savings accounts	1,191,498	1,167,810
Certificates of deposit, $250,000 or more	1,344,570	1,506,071
Other certificates of deposit	983,956	948,220
Total deposits	14,654,213	14,958,378
Brokered deposits	$ 909,700	$ 1,100,000

Deposits - Scheduled Maturities

Deposits - Scheduled Maturities of Certificates of Deposit (Details) $ in Thousands	Dec. 31, 2018USD ($)
Banking and Thrift [Abstract]
2,019	$ 1,465,426
2,020	609,146
2,021	148,640
2,022	82,711
2,023	21,833
Thereafter	770
Total	$ 2,328,526

Short-Term Borrowings - Schedul

Short-Term Borrowings - Schedule of Short-Term Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Short-term borrowings
Weighted Average Cost	2.29%	1.03%
Amount	$ 1,470,055	$ 861,039
Customer repurchase agreements
Short-term borrowings
Weighted Average Cost	0.80%	0.27%
Amount	$ 312,239	$ 232,789
Federal Home Loan Bank advances
Short-term borrowings
Weighted Average Cost	2.66%	1.31%
Amount	$ 750,000	$ 625,000
Federal funds purchased
Short-term borrowings
Weighted Average Cost	2.76%	1.26%
Amount	$ 407,816	$ 3,250
Line of credit
Short-term borrowings
Weighted Average Cost	0.00%	0.00%
Amount	$ 0	$ 0

Short-Term Borrowings - Narrati

Short-Term Borrowings - Narrative (Details) - USD ($)	Aug. 24, 2016	Dec. 18, 2015	Dec. 31, 2018	Dec. 31, 2017
Short-term borrowings
Fixed interest rate Federal Home Loan Bank advances			$ 750,000,000	$ 625,000,000
Short-term borrowings			1,470,055,000	861,039,000
Federal Home Loan Bank advances
Short-term borrowings
Short-term borrowings			750,000,000	625,000,000
Line of credit
Short-term borrowings
Unsecured line of credit		$ 35,000,000
Short-term borrowings			$ 0	$ 0
Minimum | Federal Home Loan Bank advances
Short-term borrowings
Effective interest rate for fixed rate advance (as a percent)			2.54%
Maximum | Federal Home Loan Bank advances
Short-term borrowings
Effective interest rate for fixed rate advance (as a percent)			2.91%
LIBOR
Short-term borrowings
Interest rate, basis spread (as a percent)	1.75%
LIBOR | Line of credit
Short-term borrowings
Interest rate, basis spread (as a percent)		1.75%

Long-term Borrowings - Schedule

Long-term Borrowings - Schedule of Long-term Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Aug. 24, 2016
Debt Instrument [Line Items]
Weighted Average Cost (percent)	3.91%	2.97%
Long-term borrowings	$ 349,681	$ 505,158
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Weighted Average Cost (percent)	2.85%	1.73%
Long-term borrowings	$ 94,147	$ 231,317
Notes payable
Debt Instrument [Line Items]
Weighted Average Cost (percent)	4.95%	4.14%
Long-term borrowings	$ 82,407	$ 90,807
Subordinated notes, net of issuance costs
Debt Instrument [Line Items]
Weighted Average Cost (percent)	4.00%	4.00%
Long-term borrowings	$ 173,127	$ 173,034
Term note
Debt Instrument [Line Items]
Weighted Average Cost (percent)	0.00%	3.31%
Long-term borrowings	$ 0	$ 10,000	$ 16,000

Long-term Borrowings - Narrativ

Long-term Borrowings - Narrative (Details) - USD ($)	Nov. 16, 2017	Aug. 24, 2016	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Federal Home Loan Bank advances			$ 94,100,000	$ 231,300,000
Long-term borrowings			$ 349,681,000	$ 505,158,000
Weighted average interest rate			3.91%	2.97%
Federal Home Loan Bank advances
Debt Instrument [Line Items]
Long-term borrowings			$ 94,147,000	$ 231,317,000
Weighted average interest rate			2.85%	1.73%
Notes payable to banks
Debt Instrument [Line Items]
Long-term borrowings			$ 78,400,000	$ 76,300,000
Weighted average interest rate			4.86%
Equipment pledged as collateral			$ 92,900,000	91,900,000
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Long-term borrowings			$ 4,100,000	14,500,000
Weighted average interest rate			6.59%
Unsecured term loan
Debt Instrument [Line Items]
Long-term borrowings		$ 16,000,000	$ 0	$ 10,000,000
Weighted average interest rate			0.00%	3.31%
Quarterly periodic payments		$ 1,000,000
Subordinated notes
Debt Instrument [Line Items]
Long-term borrowings			$ 173,127,000	$ 173,034,000
Weighted average interest rate			4.00%	4.00%
Amount issued	$ 175,000,000
Stated interest rate	4.00%
Minimum | Federal Home Loan Bank advances
Debt Instrument [Line Items]
Interest rate			2.73%
Minimum | Notes payable to banks
Debt Instrument [Line Items]
Interest rates (as a percent)			2.25%
Maximum | Federal Home Loan Bank advances
Debt Instrument [Line Items]
Interest rate			5.87%
Maximum | Notes payable to banks
Debt Instrument [Line Items]
Interest rates (as a percent)			7.25%
LIBOR
Debt Instrument [Line Items]
Interest rate, basis spread (as a percent)		1.75%
LIBOR | Subordinated notes
Debt Instrument [Line Items]
Interest rate, basis spread (as a percent)	1.873%

Long-term Borrowings - Schedu_2

Long-term Borrowings - Schedule of Principle Payments on Long-Term Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
2,019	$ 38,904
2,020	25,242
2,021	12,057
2,022	5,050
2,023	90,387
Thereafter	178,041
Long-term borrowings	$ 349,681	$ 505,158

Junior Subordinated Notes Iss_3

Junior Subordinated Notes Issued to Capital Trusts (Details) - USD ($)	Oct. 23, 2018	Oct. 07, 2018	Sep. 17, 2018	Aug. 06, 2018	Mar. 19, 2018	Aug. 24, 2016	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Outstanding junior subordinated notes
Principal balance									$ 121,118,000	$ 211,494,000
Loss on extinguishment of debt									$ (11,898,000)	$ 0	$ 0
Junior Subordinated Notes | Maximum
Outstanding junior subordinated notes
Period for deferment of payment of interest on notes (in years)									5 years
American Chartered Statutory Trust I [Member] | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value					$ 20,000,000
Loss on extinguishment of debt								$ (3,100,000)
American Chartered Statutory Trust I I [Member] | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value		$ 10,000,000
Loss on extinguishment of debt		$ (2,500,000)
MB Financial Capital Trust II | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value									$ 35,000,000
Interest rate, basis spread (as a percent)									1.40%
MB Financial Capital Trust II | Junior Subordinated Notes
Outstanding junior subordinated notes
Principal balance									$ 36,083,000
Interest rate, basis spread (as a percent)									1.40%
MB Financial Capital Trust III | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value									$ 10,000,000
Interest rate, basis spread (as a percent)									1.50%
MB Financial Capital Trust III | Junior Subordinated Notes
Outstanding junior subordinated notes
Principal balance									$ 10,310,000
Interest rate, basis spread (as a percent)									1.50%
MB Financial Capital Trust IV | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value									$ 20,000,000
Interest rate, basis spread (as a percent)									1.52%
MB Financial Capital Trust IV | Junior Subordinated Notes
Outstanding junior subordinated notes
Principal balance									$ 20,619,000
Interest rate, basis spread (as a percent)									1.52%
MB Financial Capital Trust V | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value									$ 30,000,000
Interest rate, basis spread (as a percent)									1.30%
MB Financial Capital Trust V | Junior Subordinated Notes
Outstanding junior subordinated notes
Principal balance									$ 30,928,000
Interest rate, basis spread (as a percent)									1.30%
MB Financial Capital Trust VI | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value									$ 22,500,000
Interest rate, basis spread (as a percent)									1.30%
MB Financial Capital Trust VI | Junior Subordinated Notes
Outstanding junior subordinated notes
Principal balance									$ 23,196,000
Interest rate, basis spread (as a percent)									1.30%
F O B B Statutory Trust I I I [Member] | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value	$ 5,000,000
Coal City Capital Trust I [Member] | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value				$ 25,000,000
Loss on extinguishment of debt							$ (341,000)
TAYC Capital Trust II [Member] | Trust preferred securities issued by each trust
Outstanding junior subordinated notes
Face Value			$ 40,000,000
Loss on extinguishment of debt							$ (5,900,000)
LIBOR
Outstanding junior subordinated notes
Interest rate, basis spread (as a percent)						1.75%
LIBOR | American Chartered Statutory Trust I [Member] | Junior Subordinated Notes
Outstanding junior subordinated notes
Interest rate, basis spread (as a percent)					3.60%
LIBOR | American Chartered Statutory Trust I I [Member] | Junior Subordinated Notes
Outstanding junior subordinated notes
Interest rate, basis spread (as a percent)		2.75%
LIBOR | F O B B Statutory Trust I I I [Member] | Junior Subordinated Notes
Outstanding junior subordinated notes
Interest rate, basis spread (as a percent)	2.80%
LIBOR | Coal City Capital Trust I [Member] | Junior Subordinated Notes
Outstanding junior subordinated notes
Interest rate, basis spread (as a percent)				1.80%
LIBOR | TAYC Capital Trust II [Member] | Junior Subordinated Notes
Outstanding junior subordinated notes
Interest rate, basis spread (as a percent)			2.68%

Lease Commitments and Rental _3

Lease Commitments and Rental Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Rents
Net rental expense	$ 11,800	$ 11,300	$ 10,900
Office space
Gross Rents
2,019	11,902
2,020	8,272
2,021	6,988
2,022	5,452
2,023	4,308
Thereafter	17,248
Total	54,170
Sublease Rents
2,019	1,276
2,020	532
2,021	195
2,022	16
2,023	0
Thereafter	0
Total	2,019
Net Rents
2,019	10,626
2,020	7,740
2,021	6,793
2,022	5,436
2,023	4,308
Thereafter	17,248
Total	$ 52,151

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Requisite service period to participate in contribution plan (in months)	3 months
Employee contribution limit per calendar year (as a percent of compensation)	75.00%
Employer contribution limit per calendar year (as a percent of compensation)	3.50%
Company's expected contribution to plan during current fiscal year	$ 16,700
Company's total contribution to plan		$ 17,200	$ 14,800
Deferred Compensation Plan
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defer payment, participant limit per calendar year (as a percent of compensation)	100.00%
Estimated discretionary company contributions	$ 1,500
Actual employer's contribution		$ 869	$ 806
Deferred Compensation Plan | Chief executive officer
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Employer's contribution to deferred compensation plan (as a percent of base salary)	20.00%
Fair market value of assets held in other publicly traded funds	$ 27,900
Increases in fair market value of assets and obligation	$ (1,400)

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax asset:
Allowance for credit losses	$ 42,208	$ 42,560
State net operating loss carryforwards	19,495	26,981
Other real estate owned	2,182	1,905
Stock options and restricted stock	5,875	5,929
Loans	7,766	12,762
Deferred compensation	7,812	6,918
Tax credit carryforwards	13,525	40,197
Bonus accrual	8,620	2,172
Other items	311	1,797
Total deferred tax asset	107,794	141,221
Valuation allowance	0	0
Total deferred tax asset, net of valuation allowance	107,794	141,221
Deferred tax liability:
Equipment leasing	(121,142)	(127,465)
Premises and equipment	(20,856)	(17,250)
Mortgage servicing rights	(66,749)	(62,091)
Deferred income from FDIC-assisted transactions	(12,583)	(20,895)
Deferred loan costs	(10,604)	(7,555)
Investment securities	(6,876)	(5,933)
FHLB stock dividends	(2,141)	(2,195)
Core deposit intangible	(7,239)	(9,023)
Other items	(4,794)	(3,683)
Total deferred tax liability	(252,984)	(256,090)
Net deferred tax liability	(145,190)	(114,869)
Net unrealized holding gain on investment securities available for sale	1,842	(959)
Net deferred tax liability	$ (143,348)	$ (115,828)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018
Operating loss carryforwards
Tax benefit arising from re-measurement of deferred tax asset and liabilities from Tax Cuts and Jobs Act	$ 104.2
Federal Alternative Minimum Tax Credit Carryforward
Operating loss carryforwards
Tax credit carryforward		$ 13.5
Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Measurement Period Adjustment, Income Tax Expense (Benefit)		13.7
State
Operating loss carryforwards
Net operating loss carryforwards		1.3
Illinois | State
Operating loss carryforwards
Net operating loss carryforwards		$ 258.7

Income Taxes - Income Tax Attri

Income Taxes - Income Tax Attributable to Continuing Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current expense (benefit):
Federal	$ (4,850)	$ 12,346	$ 26,081
State	12,290	6,994	7,204
Foreign	495	157	42
Current income tax expense (benefit)	7,935	19,497	33,327
Deferred expense (benefit):
Federal	31,244	(45,401)	37,690
State	(923)	10,679	8,227
Foreign	0	0	0
Deferred income tax expense (benefit)	30,321	(34,722)	45,917
Income tax expense	$ 38,256	$ (15,225)	$ 79,244

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Rate to Effective Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory federal income tax rate (as a percent)	21.00%	35.00%	35.00%
Federal income tax expense at expected statutory rate	$ 52,956	$ 101,085	$ 88,683
(Decrease) increase due to:
Tax exempt income, net	(9,708)	(17,164)	(18,214)
Tax benefit resulting from change in tax rates	(13,741)	(106,563)	0
State tax expense net of federal impact	8,980	11,487	10,030
Stock-based compensation excess tax benefits	(1,597)	(3,195)	(2,330)
Non-deductible contingent consideration	406	138	1,026
Non-includable increase in cash surrender value of life insurance	(1,046)	(1,889)	(1,432)
Non-deductible merger expense	878	0	298
Adjustment of unrecognized tax benefit	(8)	94	1
Other items, net	1,136	782	1,182
Income tax expense	$ 38,256	$ (15,225)	$ 79,244

Income Taxes - Change in Unreco

Income Taxes - Change in Unrecognized Tax Benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Unrecognized Tax Benefit Without Interest
Balance at the beginning of the period	$ 113
Decreases related to prior year tax positions	(8)
Balance at the end of the period	105
Interest on unrecognized Tax Benefit
Balance at the beginning of the period	0
Decreases related to prior year tax positions	0
Balance at the end of the period	0
Total Unrecognized Tax Benefit Including Interest
Balance at the beginning of the period	113
Decreases related to prior year tax positions	(8)
Balance at the end of the period	$ 105

Commitments and Contingencies -

Commitments and Contingencies - Financial Instruments Outstanding Representing Off-Balance Sheet Credit Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Home equity lines
Long-term Purchase Commitment [Line Items]
Dollar amount of line of credit outstanding	$ 179,521	$ 203,922
Other commitments
Long-term Purchase Commitment [Line Items]
Dollar amount of line of credit outstanding	4,058,853	4,073,044
Standby
Long-term Purchase Commitment [Line Items]
Dollar amount of line of credit outstanding	173,755	161,014
Commercial
Long-term Purchase Commitment [Line Items]
Dollar amount of line of credit outstanding	$ 5,657	$ 2,248

Commitments and Contingencies_2

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Concentrations of credit risk
Maximum maturity period for letters of credit (in years)	5 years
Increase in maximum potential amount of future payments under letters of credit	$ 16.2
Dollar amount of letters of credit outstanding	$ 179.4	$ 163.3
Letters of credit issued or renewed		$ 158.2
States and political subdivisions | State of Illinois
Concentrations of credit risk
Percentage of investments issued by states and political subdivisions that were within the state of Illinois	20.00%

Regulatory Matters (Details)

Regulatory Matters (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Total capital (to risk-weighted assets):
Total capital (to risk-weighted assets): Actual Amount	$ 2,379,813	$ 2,428,301
Total capital (to risk-weighted assets): Actual Ratio (as a percent)	13.67%	14.23%
Total capital (to risk-weighted assets): For Capital Adequacy Purposes Amount	$ 1,392,791	$ 1,364,733
Total capital (to risk-weighted assets): For Capital Adequacy Purposes Ratio (as a percent)	8.00%	8.00%
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets): Actual Amount	$ 1,959,413	$ 1,910,336
Tier 1 capital (to risk-weighted assets): Actual Ratio (as a percent)	11.25%	11.20%
Tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Amount	$ 1,044,593	$ 1,023,550
Tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Ratio (as a percent)	6.00%	6.00%
Common equity tier 1 capital (to risk-weighted assets):
Common equity tier 1 capital (to risk-weighted assets): Actual Amount	$ 1,764,694	$ 1,603,479
Common equity tier 1 capital (to risk-weighted assets): Actual Ratio (as a percent)	10.14%	9.40%
Common equity tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Amount	$ 783,445	$ 767,662
Common equity tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Ratio (as a percent)	4.50%	4.50%
Tier 1 capital (to average assets):
Tier 1 capital (to average assets): Actual Amount	$ 1,959,413	$ 1,910,336
Tier 1 capital (to average assets): Actual Ratio (as a percent)	10.50%	10.02%
Tier 1 capital (to average assets): For Capital Adequacy Purposes Amount	$ 746,268	$ 762,370
Tier 1 capital (to average assets): For Capital Adequacy Purposes Ratio (as a percent)	4.00%	4.00%
MB Financial Bank
Total capital (to risk-weighted assets):
Total capital (to risk-weighted assets): Actual Amount	$ 2,264,296	$ 2,217,547
Total capital (to risk-weighted assets): Actual Ratio (as a percent)	13.05%	13.03%
Total capital (to risk-weighted assets): For Capital Adequacy Purposes Amount	$ 1,388,457	$ 1,361,855
Total capital (to risk-weighted assets): For Capital Adequacy Purposes Ratio (as a percent)	8.00%	8.00%
Total capital (to risk-weighted assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,735,571	$ 1,702,318
Total capital (to risk-weighted assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10.00%	10.00%
Tier 1 capital (to risk-weighted assets):
Tier 1 capital (to risk-weighted assets): Actual Amount	$ 1,927,240	$ 1,883,140
Tier 1 capital (to risk-weighted assets): Actual Ratio (as a percent)	11.10%	11.06%
Tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Amount	$ 1,041,343	$ 1,021,391
Tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Ratio (as a percent)	6.00%	6.00%
Tier 1 capital (to risk-weighted assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,388,457	$ 1,361,855
Tier 1 capital (to risk-weighted assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	8.00%	8.00%
Common equity tier 1 capital (to risk-weighted assets):
Common equity tier 1 capital (to risk-weighted assets): Actual Amount	$ 1,925,076	$ 1,883,140
Common equity tier 1 capital (to risk-weighted assets): Actual Ratio (as a percent)	11.09%	11.06%
Common equity tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Amount	$ 781,007	$ 766,043
Common equity tier 1 capital (to risk-weighted assets): For Capital Adequacy Purposes Ratio (as a percent)	4.50%	4.50%
Common equity tier 1 capital (to risk-weighted assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,128,121	$ 1,106,507
Common equity tier 1 capital (to risk-weighted assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.50%	6.50%
Tier 1 capital (to average assets):
Tier 1 capital (to average assets): Actual Amount	$ 1,927,240	$ 1,883,140
Tier 1 capital (to average assets): Actual Ratio (as a percent)	10.35%	9.90%
Tier 1 capital (to average assets): For Capital Adequacy Purposes Amount	$ 744,676	$ 760,797
Tier 1 capital (to average assets): For Capital Adequacy Purposes Ratio (as a percent)	4.00%	4.00%
Tier 1 capital (to average assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 930,845	$ 950,996
Tier 1 capital (to average assets): To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5.00%	5.00%

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	$ 1,855,682,000
Equity Securities, FV-NI	11,075,000	$ 0
Financial assets
Securities available for sale, at fair value		1,408,326,000
Loans held for sale	45,550,000	548,578,000
Total loans, excluding purchased credit impaired loans	13,951,082,000	13,846,318,000
Mortgage servicing rights	284,898,000	276,279,000
Derivative financial instruments	29,458,000	17,540,000
Financial liabilities
Derivative financial instruments	21,933,000	27,947,000
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	75,141,000
U.S. Government sponsored agencies and enterprises
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	5,024,000
Financial assets
Securities available for sale, at fair value		23,007,000
States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	341,477,000
Financial assets
Securities available for sale, at fair value		379,325,000
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,402,453,000
Financial assets
Securities available for sale, at fair value		852,699,000
Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	31,587,000
Financial assets
Securities available for sale, at fair value		72,035,000
Corporate bonds
Financial assets
Securities available for sale, at fair value		70,197,000
Equity securities
Financial assets
Securities available for sale, at fair value		11,063,000
Recurring basis
Financial assets
Loans held for sale	45,550,000	548,578,000
Total loans, excluding purchased credit impaired loans	42,665,000	40,531,000
Assets held in trust for deferred compensation	27,882,000	21,410,000
Financial liabilities
Other liabilities	27,882,000	21,410,000
Derivative financial instruments	41,300,000	40,296,000
Recurring basis | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	75,141,000
Recurring basis | U.S. Government sponsored agencies and enterprises
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	5,024,000
Financial assets
Securities available for sale, at fair value		23,007,000
Recurring basis | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	341,477,000
Financial assets
Securities available for sale, at fair value		379,325,000
Recurring basis | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,402,453,000
Financial assets
Securities available for sale, at fair value		852,699,000
Recurring basis | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	31,587,000
Financial assets
Securities available for sale, at fair value		72,035,000
Recurring basis | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		70,197,000
Recurring basis | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	11,075,000
Financial assets
Securities available for sale, at fair value		11,063,000
Recurring basis | Mortgage Servicing Rights
Financial assets
Mortgage servicing rights	284,898,000	276,279,000
Recurring basis | Mortgage Derivative Instruments
Financial assets
Derivative financial instruments	45,168,000	31,499,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	75,141,000
Equity Securities, FV-NI	11,075,000
Financial assets
Securities available for sale, at fair value		11,063,000
Loans held for sale	0	0
Total loans, excluding purchased credit impaired loans	0	0
Assets held in trust for deferred compensation	27,882,000	21,410,000
Derivative financial instruments	1,534,000	389,000
Financial liabilities
Other liabilities	27,882,000	21,410,000
Derivative financial instruments	215,000	1,072,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	75,141,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government sponsored agencies and enterprises
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities
Financial assets
Securities available for sale, at fair value		11,063,000
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage Servicing Rights
Financial assets
Mortgage servicing rights	0	0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage Derivative Instruments
Financial assets
Derivative financial instruments	1,534,000	389,000
Recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,780,259,000
Equity Securities, FV-NI	0
Financial assets
Securities available for sale, at fair value		1,396,900,000
Loans held for sale	45,550,000	548,578,000
Total loans, excluding purchased credit impaired loans	42,665,000	40,531,000
Assets held in trust for deferred compensation	0	0
Derivative financial instruments	43,526,000	29,539,000
Financial liabilities
Other liabilities	0	0
Derivative financial instruments	41,085,000	39,224,000
Recurring basis | Significant Other Observable Inputs (Level 2) | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Government sponsored agencies and enterprises
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	5,024,000
Financial assets
Securities available for sale, at fair value		23,007,000
Recurring basis | Significant Other Observable Inputs (Level 2) | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	341,195,000
Financial assets
Securities available for sale, at fair value		378,996,000
Recurring basis | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,402,453,000
Financial assets
Securities available for sale, at fair value		852,665,000
Recurring basis | Significant Other Observable Inputs (Level 2) | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	31,587,000
Financial assets
Securities available for sale, at fair value		72,035,000
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		70,197,000
Recurring basis | Significant Other Observable Inputs (Level 2) | Equity securities
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Significant Other Observable Inputs (Level 2) | Mortgage Servicing Rights
Financial assets
Mortgage servicing rights	0	0
Recurring basis | Significant Other Observable Inputs (Level 2) | Mortgage Derivative Instruments
Financial assets
Derivative financial instruments	43,526,000	29,539,000
Recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	282,000
Equity Securities, FV-NI	0
Financial assets
Securities available for sale, at fair value		363,000
Loans held for sale	0	0
Total loans, excluding purchased credit impaired loans	0	0
Assets held in trust for deferred compensation	0	0
Derivative financial instruments	108,000	1,571,000
Financial liabilities
Other liabilities	0	0
Derivative financial instruments	0	0
Recurring basis | Significant Unobservable Inputs (Level 3) | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. Government sponsored agencies and enterprises
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Significant Unobservable Inputs (Level 3) | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	282,000
Financial assets
Securities available for sale, at fair value		329,000
Recurring basis | Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		34,000
Recurring basis | Significant Unobservable Inputs (Level 3) | Commercial mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Significant Unobservable Inputs (Level 3) | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Significant Unobservable Inputs (Level 3) | Equity securities
Financial assets
Securities available for sale, at fair value		0
Recurring basis | Significant Unobservable Inputs (Level 3) | Mortgage Servicing Rights
Financial assets
Mortgage servicing rights	284,898,000	276,279,000
Recurring basis | Significant Unobservable Inputs (Level 3) | Mortgage Derivative Instruments
Financial assets
Derivative financial instruments	$ 108,000	$ 1,571,000

Fair Value Measurements - Unobs

Fair Value Measurements - Unobservable Inputs Used in the Fair Value Measurement (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	$ 1,855,682,000
Available-for-sale Securities		$ 1,408,326,000
Mortgage servicing rights, at fair value	284,898,000	276,279,000
Derivative financial instruments	29,458,000	17,540,000
States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	341,477,000
Available-for-sale Securities		379,325,000
Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,402,453,000
Available-for-sale Securities		852,699,000
Recurring basis | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	341,477,000
Available-for-sale Securities		379,325,000
Recurring basis | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	1,402,453,000
Available-for-sale Securities		852,699,000
Recurring basis | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Mortgage servicing rights, at fair value	284,898,000	276,279,000
Recurring basis | Mortgage Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Derivative financial instruments	45,168,000	31,499,000
Significant Unobservable Inputs (Level 3) | Recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	282,000
Available-for-sale Securities		363,000
Derivative financial instruments	108,000	1,571,000
Significant Unobservable Inputs (Level 3) | Recurring basis | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	282,000
Available-for-sale Securities		$ 329,000
Credit assumption (as a percent)		45.00%
Significant Unobservable Inputs (Level 3) | Recurring basis | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Debt Securities, Available-for-sale	0
Available-for-sale Securities		$ 34,000
Significant Unobservable Inputs (Level 3) | Recurring basis | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Mortgage servicing rights, at fair value	284,898,000	276,279,000
Significant Unobservable Inputs (Level 3) | Recurring basis | Mortgage Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Derivative financial instruments	$ 108,000	$ 1,571,000
Significant Unobservable Inputs (Level 3) | Recurring basis | Minimum | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Credit assumption (as a percent)	35.00%
Significant Unobservable Inputs (Level 3) | Recurring basis | Minimum | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Weighted average prepayment speed (CPR)		1.00%
Significant Unobservable Inputs (Level 3) | Recurring basis | Minimum | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Weighted average prepayment speed (CPR)	6.50%	6.70%
Weighted average discount rate	9.53%	9.53%
Maturity period (in months)	328 months	324 months
Weighted average delinquency rate	1.92%	2.42%
Weighted average costs to service	$ 67	$ 67
Additive delinquent costs to service	$ 175	$ 175
Significant Unobservable Inputs (Level 3) | Recurring basis | Minimum | Mortgage Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Expected closing ratio	70.00%	70.00%
Expected delivery price	0.9948%	0.9738%
Significant Unobservable Inputs (Level 3) | Recurring basis | Maximum | States and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Credit assumption (as a percent)	40.00%
Significant Unobservable Inputs (Level 3) | Recurring basis | Maximum | Residential mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Weighted average prepayment speed (CPR)		3.00%
Significant Unobservable Inputs (Level 3) | Recurring basis | Maximum | Mortgage Servicing Rights
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Weighted average prepayment speed (CPR)	7.30%	7.80%
Weighted average discount rate	11.08%	11.06%
Maturity period (in months)	358 months	358 months
Weighted average delinquency rate	4.36%	5.30%
Weighted average costs to service	$ 227	$ 227
Additive delinquent costs to service	$ 1,000	$ 1,000
Significant Unobservable Inputs (Level 3) | Recurring basis | Maximum | Mortgage Derivative Instruments
Fair Value, Assets and Liabilities Measured on Recurring and a Nonrecurring Basis [Line Items]
Expected closing ratio	95.00%	95.00%
Expected delivery price	1.0531%	1.0687%

Fair Value Measurements - Key E

Fair Value Measurements - Key Economic Assumptions Used in Measuring Fair Value (Details) - Mortgage Servicing Rights	12 Months Ended
	Dec. 31, 2018USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Impact on fair value of 10% adverse change	$ (8,462,000)
Impact on fair value of 20% adverse change	(16,499,000)
Impact on fair value of 10% adverse change	(12,045,000)
Impact on fair value of 20% adverse change	(23,128,000)
Impact on fair value of 10% adverse change	(2,591,000)
Impact on fair value of 20% adverse change	(4,558,000)
Impact on fair value of 10% adverse change	(5,177,000)
Impact on fair value of 20% adverse change	$ (10,355,000)
Weighted Average
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Weighted average prepayment speed (CPR)	6.76%
Weighted average discount rate	9.84%
Weighted average delinquency rate	4.08%
Weighted average costs to service	$ 90

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information About Financial Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Percentage of allowance for impaired real estate loans	100.00%
Investment Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	$ 363	$ 544
Purchases	0	0
Originations	0	0
Included in earnings	(12)	0
Principal payments	(69)	(181)
Balance at the end of the period	282	363
Mortgage Servicing Rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	276,279	238,011
Purchases	161	865
Originations	30,843	59,810
Included in earnings	(22,385)	(22,407)
Principal payments	0	0
Balance at the end of the period	284,898	276,279
Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	1,571	3,160
Purchases	0	0
Originations	0	0
Included in earnings	(1,463)	(1,589)
Principal payments	0	0
Balance at the end of the period	$ 108	$ 1,571

Fair Value Measurements - Uno_2

Fair Value Measurements - Unobservable Inputs Used in Fair Value of Assets on a Nonrecurring Basis (Details) - Nonrecurring basis - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financial Assets:
Impaired loans	$ 61,005	$ 60,569
Foreclosed assets	11,354	15,113
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Impaired loans	0	0
Foreclosed assets	0	0
Significant Other Observable Inputs (Level 2)
Financial Assets:
Impaired loans	0	0
Foreclosed assets	0	0
Significant Unobservable Inputs (Level 3)
Financial Assets:
Impaired loans	61,005	60,569
Foreclosed assets	$ 11,354	$ 15,113
Significant Unobservable Inputs (Level 3) | Minimum
Financial Assets:
Appraisal adjustment, impaired loans	5.00%	5.00%
Appraisal adjustment, foreclosed assets	5.00%	5.00%
Significant Unobservable Inputs (Level 3) | Maximum
Financial Assets:
Appraisal adjustment, impaired loans	10.00%	10.00%
Appraisal adjustment, foreclosed assets	10.00%	10.00%

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Maximum maturity period of short-term borrowings where carrying value approximates fair value (in days)	90 days
Minimum maturity period of short-term borrowings where fair value is based on discounted value of contractual cash flows (in days)	90 days
Estimated fair values of financial instruments
Available-for-sale Securities		$ 1,408,326
Debt Securities, Available-for-sale	$ 1,855,682
Financial Assets:
Cash and due from banks	503,153	397,880
Interest bearing deposits with banks	147,254	181,341
Investment securities held to maturity	919,660	992,455
Equity Securities, FV-NI	11,075	0
Non-marketable securities - FHLB and FRB stock	113,957	114,111
Loans held for sale	45,550	548,578
Derivative financial instruments	29,458	17,540
Financial Liabilities:
Non-interest bearing deposits	6,152,163	6,381,512
Interest bearing deposits	8,502,050	8,576,866
Short-term borrowings	1,470,055	861,039
Junior subordinated notes issued to capital trusts	121,118	211,494
Derivative financial instruments	21,933	27,947
Carrying Amount
Estimated fair values of financial instruments
Available-for-sale Securities		1,408,326
Debt Securities, Available-for-sale	1,855,682
Financial Assets:
Cash and due from banks	503,153	397,880
Interest bearing deposits with banks	147,254	181,341
Investment securities held to maturity	901,684	959,082
Equity Securities, FV-NI	11,075
Non-marketable securities - FHLB and FRB stock	113,957	114,111
Loans held for sale	45,550	548,578
Loans, net	13,873,605	13,808,352
Accrued interest receivable	68,801	63,589
Derivative financial instruments	45,168	31,499
Financial Liabilities:
Non-interest bearing deposits	6,152,163	6,381,512
Interest bearing deposits	8,502,050	8,576,866
Short-term borrowings	1,470,055	861,039
Long-term borrowings	349,681	505,158
Junior subordinated notes issued to capital trusts	121,118	211,494
Accrued interest payable	7,216	6,458
Derivative financial instruments	41,300	40,296
Estimated Fair Value
Estimated fair values of financial instruments
Available-for-sale Securities		1,408,326
Debt Securities, Available-for-sale	1,855,682
Financial Assets:
Cash and due from banks	503,153	397,880
Interest bearing deposits with banks	147,254	181,341
Investment securities held to maturity	919,660	992,455
Equity Securities, FV-NI	11,075
Non-marketable securities - FHLB and FRB stock	113,957	114,111
Loans held for sale	45,550	548,578
Loans, net	13,937,096	13,988,392
Accrued interest receivable	68,801	63,589
Derivative financial instruments	45,168	31,499
Financial Liabilities:
Non-interest bearing deposits	6,152,163	6,381,512
Interest bearing deposits	8,492,037	8,569,368
Short-term borrowings	1,470,190	860,676
Long-term borrowings	351,141	513,725
Junior subordinated notes issued to capital trusts	89,321	170,965
Accrued interest payable	7,216	6,458
Derivative financial instruments	41,300	40,296
Recurring basis
Financial Assets:
Loans held for sale	45,550	548,578
Financial Liabilities:
Derivative financial instruments	41,300	40,296
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Estimated fair values of financial instruments
Available-for-sale Securities		11,063
Debt Securities, Available-for-sale	75,141
Financial Assets:
Cash and due from banks	503,153	397,880
Interest bearing deposits with banks	147,254	181,341
Investment securities held to maturity	0	0
Equity Securities, FV-NI	11,075
Non-marketable securities - FHLB and FRB stock	0	0
Loans held for sale	0	0
Loans, net	0	0
Accrued interest receivable	68,801	63,589
Derivative financial instruments	1,534	389
Financial Liabilities:
Non-interest bearing deposits	6,152,163	6,381,512
Interest bearing deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Junior subordinated notes issued to capital trusts	0	0
Accrued interest payable	7,216	6,458
Derivative financial instruments	215	1,072
Recurring basis | Significant Other Observable Inputs (Level 2)
Estimated fair values of financial instruments
Available-for-sale Securities		1,396,900
Debt Securities, Available-for-sale	1,780,259
Financial Assets:
Cash and due from banks	0	0
Interest bearing deposits with banks	0	0
Investment securities held to maturity	919,660	992,455
Equity Securities, FV-NI	0
Non-marketable securities - FHLB and FRB stock	0	0
Loans held for sale	45,550	548,578
Loans, net	42,665	40,531
Accrued interest receivable	0	0
Derivative financial instruments	43,526	29,539
Financial Liabilities:
Non-interest bearing deposits	0	0
Interest bearing deposits	0	0
Short-term borrowings	0	0
Long-term borrowings	0	0
Junior subordinated notes issued to capital trusts	0	0
Accrued interest payable	0	0
Derivative financial instruments	41,085	39,224
Recurring basis | Significant Unobservable Inputs (Level 3)
Estimated fair values of financial instruments
Available-for-sale Securities		363
Debt Securities, Available-for-sale	282
Financial Assets:
Cash and due from banks	0	0
Interest bearing deposits with banks	0	0
Investment securities held to maturity	0	0
Equity Securities, FV-NI	0
Non-marketable securities - FHLB and FRB stock	113,957	114,111
Loans held for sale	0	0
Loans, net	13,894,431	13,947,861
Accrued interest receivable	0	0
Derivative financial instruments	108	1,571
Financial Liabilities:
Non-interest bearing deposits	0	0
Interest bearing deposits	8,492,037	8,569,368
Short-term borrowings	1,470,190	860,676
Long-term borrowings	351,141	513,725
Junior subordinated notes issued to capital trusts	89,321	170,965
Accrued interest payable	0	0
Derivative financial instruments	$ 0	$ 0

Stock Incentive Plans - Narrati

Stock Incentive Plans - Narrative (Details) - USD ($) $ in Thousands	May 28, 2014	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2013	Aug. 18, 2014
Impact of the share-based payment plans in the financial statements
Total compensation expense for share-based payment plans during the year		$ 18,727	$ 17,476	$ 16,868
Amount of related income tax benefit recognized in income		$ 6,897	$ 10,338	$ 8,983
Stock-based compensation
Numerator of shares granted beyond threshold limit (in shares)		2
Omnibus Incentive Plan (the "Omnibus Plan")
Stock-based compensation
Additional authorized shares (in shares)	3,100,000
Common shares authorized for issuance (in shares)	11,400,000
Percentage of shares authorized for issuance	10.00%
Minimum vesting period (in years)	3 years
Shares available for future grants (in shares)		2,138,446
Unrecognized compensation cost		$ 21,200
Expected weighted-average period for recognition of unrecognized compensation expense (in years)		2 years
Omnibus Incentive Plan (the "Omnibus Plan") | Taylor Capital Group, Inc.
Stock-based compensation
Common shares authorized for issuance (in shares)						13,800,000
Additional shares authorized (in shares)	2,400,000
Stock options
Stock-based compensation
Continuous service period for vesting of option awards (in years)		4 years
Contractual terms of option awards (in years)		10 years
Stock options | Director
Stock-based compensation
Minimum vesting period (in years)		5 years
Maximum percentage of fees with an option to be received in equity-based incentive awards		70.00%
Period of restriction for sale of underlying shares (in months)		6 months
Restricted stock and restricted stock units | Minimum
Stock-based compensation
Minimum vesting period (in years)		2 years
Restricted stock and restricted stock units | Maximum
Stock-based compensation
Minimum vesting period (in years)		4 years
Restricted stock | Director
Stock-based compensation
Minimum vesting period (in years)		1 year
Maximum percentage of fees with an option to be received in equity-based incentive awards		100.00%
Performance-based restricted stock units
Stock-based compensation
Minimum vesting period (in years)		3 years
Shares issued (in shares)		71,567	65,476	80,780	71,560
Performance based restricted units performance period (in years)		3 years
Share based compensation shares earned based on shares issued (percent)		0.00%
Share based compensation restricted stock units multiplier (in percent)		100.00%
Performance-based restricted stock units | Minimum
Stock-based compensation
Percentage of shares earned to number of units issued		0.00%
Performance-based restricted stock units | Maximum
Stock-based compensation
Percentage of shares earned to number of units issued		175.00%

Stock Incentive Plans - Stock O

Stock Incentive Plans - Stock Options Outstanding (Details) - Stock options - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Number of Options
Options outstanding at the beginning of the period (in shares)	1,721,978
Granted (in shares)	175,501
Exercised (in shares)	(493,984)
Expired (in shares)	(2,362)
Forfeited or cancelled (in shares)	(28,939)
Options outstanding at the end of the period (in shares)	1,372,194	1,721,978
Options exercisable at end of the period (in shares)	887,401
Weighted Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share)	$ 29.10
Granted (in dollars per share)	41.26
Exercised (in dollars per share)	26.35
Expired (in dollars per share)	32.99
Forfeited or cancelled (in dollars per share)	31.63
Options outstanding at the end of the period (in dollars per share)	31.58	$ 29.10
Options exercisable at end of the period (in dollars per share)	$ 28.68
Weighted Average Remaining Contractual Term (in years)
Options outstanding	5 years 8 months 15 days	5 years 2 months 10 days
Options exercisable at end of the period	4 years 6 months 18 days
Aggregate Intrinsic Value (in thousands)
Options outstanding at the end of the period	$ 12,327
Options exercisable at the end of the period	$ 10,137

Stock Incentive Plans - Options

Stock Incentive Plans - Options Granted (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair value assumptions
Risk-free interest rate	2.79%	2.18%	1.44%
Expected volatility of Company’s stock	25.96%	22.71%	28.08%
Expected dividend yield	2.08%	1.68%	2.19%
Expected life of options (years)	5 years 6 months	5 years 9 months	5 years 6 months
Weighted average fair value per option of options granted during the year (in dollars per share)	$ 9.21	$ 9.35	$ 6.66
Intrinsic value of options exercised	$ 10.6	$ 6.1	$ 7

Stock Incentive Plans - Restric

Stock Incentive Plans - Restricted Shares (Details) - Restricted stock and restricted stock units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of Shares
Shares and Units Outstanding at the Beginning of the Period (in shares)	973,201
Granted (in shares)	428,752
Vested (in shares)	(371,640)
Forfeited or cancelled (in shares)	(114,146)
Shares and Units Outstanding at the End of the Period (in shares)	916,167	973,201
Weighted Average Grant Date Fair Value
Shares and Units Outstanding at the Beginning of the Period (in dollars per share)	$ 37.03
Granted (in dollars per share)	41.65
Vested (in dollars per share)	35.17
Forfeited or cancelled (in dollars per share)	35.89
Shares and Units Outstanding at the at the end of the period (in dollars per share)	$ 40.09	$ 37.03
Intrinsic value of restricted shares vested	$ 15.5	$ 17.6	$ 15.9

Derivative Financial Instrume_3

Derivative Financial Instruments - Schedule of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net amount payable under interest rate swap		$ 1
Interest rate swap credit risk exposure	$ 17,400
Credit Risk Exposure of Interest Rate Derivative, Secured By Underlying Collateral	14,500
Credit Risk Exposure of Interest Rate Derivative, Secured By Cash And Investment Securities	2,900
Derivative [Line Items]
Asset Derivatives, Notional Amount	2,876,327	3,142,730
Asset Derivatives, Estimated Fair Value	45,168	31,499
Liability Derivatives, Notional Amount	2,570,781	3,591,647
Liability Derivatives, Estimated Fair Value	(41,300)	(40,296)
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	10,338	(20,511)	$ 8,036
Stand-alone derivative instruments
Derivative [Line Items]
Asset Derivatives, Notional Amount	2,876,327	3,142,730
Asset Derivatives, Estimated Fair Value	45,168	31,499
Liability Derivatives, Notional Amount	2,570,776	3,591,589
Liability Derivatives, Estimated Fair Value	(41,300)	(40,295)
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	10,337	(20,514)	8,031
Commercial loan interest rate swaps
Derivative [Line Items]
Liability Derivatives, Notional Amount	5
Interest rate swap contracts | Derivative instruments designated as hedges of fair value
Derivative [Line Items]
Asset Derivatives, Notional Amount	0	0
Asset Derivatives, Estimated Fair Value	0	0
Liability Derivatives, Notional Amount	5	58
Liability Derivatives, Estimated Fair Value	0	(1)
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	1	3	5
Interest rate swap contracts | Stand-alone derivative instruments
Derivative [Line Items]
Asset Derivatives, Notional Amount	1,803,901	1,563,109
Asset Derivatives, Estimated Fair Value	31,222	21,217
Liability Derivatives, Notional Amount	1,803,901	1,563,109
Liability Derivatives, Estimated Fair Value	(31,222)	(21,217)
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	6,253	8,233	7,571
Interest rate swap contracts | Stand-alone derivative instruments | Mortgage Banking
Derivative [Line Items]
Asset Derivatives, Notional Amount	310,000	458,000
Asset Derivatives, Estimated Fair Value	8,235	4,479
Liability Derivatives, Notional Amount	225,000	1,008,000
Liability Derivatives, Estimated Fair Value	(6,079)	(14,360)
Interest rate options contracts | Stand-alone derivative instruments
Derivative [Line Items]
Asset Derivatives, Notional Amount	465,902	372,927
Asset Derivatives, Estimated Fair Value	2,663	1,887
Liability Derivatives, Notional Amount	465,902	372,927
Liability Derivatives, Estimated Fair Value	(2,663)	(1,887)
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	0	0	36
Foreign exchange contracts | Stand-alone derivative instruments
Derivative [Line Items]
Asset Derivatives, Notional Amount	49,327	40,713
Asset Derivatives, Estimated Fair Value	1,393	1,934
Liability Derivatives, Notional Amount	46,845	34,029
Liability Derivatives, Estimated Fair Value	(1,117)	(1,759)
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	612	269	970
Spot foreign exchange contracts | Stand-alone derivative instruments
Derivative [Line Items]
Asset Derivatives, Notional Amount	7,026	1,424
Asset Derivatives, Estimated Fair Value	12	23
Liability Derivatives, Notional Amount	1,628	24
Liability Derivatives, Estimated Fair Value	(4)	0
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	3,018	2,682	963
Treasury futures contracts | Stand-alone derivative instruments | Mortgage Banking
Derivative [Line Items]
Asset Derivatives, Notional Amount	152,500	28,000
Asset Derivatives, Estimated Fair Value	794	39
Liability Derivatives, Notional Amount	5,000	30,000
Liability Derivatives, Estimated Fair Value	(2)	(222)
TBA mortgage securities | Stand-alone derivative instruments | Mortgage Banking
Derivative [Line Items]
Asset Derivatives, Notional Amount	75,000	15,000
Asset Derivatives, Estimated Fair Value	741	16
Liability Derivatives, Notional Amount	0	100,000
Liability Derivatives, Estimated Fair Value	0	(63)
Forward loan sale commitments | Stand-alone derivative instruments | Mortgage Banking
Derivative [Line Items]
Asset Derivatives, Notional Amount	0	259,000
Asset Derivatives, Estimated Fair Value	0	333
Liability Derivatives, Notional Amount	22,500	483,500
Liability Derivatives, Estimated Fair Value	(213)	(787)
Interest rate lock commitments | Stand-alone derivative instruments | Mortgage Banking
Derivative [Line Items]
Asset Derivatives, Notional Amount	12,671	404,557
Asset Derivatives, Estimated Fair Value	108	1,571
Liability Derivatives, Notional Amount	0	0
Liability Derivatives, Estimated Fair Value	0	0
Mortgage related derivatives | Stand-alone derivative instruments
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amounts of gain or (loss) recognized in income on derivatives	$ 454	$ (31,698)	$ (1,509)

Derivative Financial Instrume_4

Derivative Financial Instruments - Financial Instruments that are Eligible for Offset on the Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Financial Assets, Gross Amount Recognized	$ 29,458	$ 17,540
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	29,458	17,540
Financial Liabilities, Gross Amount Recognized	21,933	27,947
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	21,933	27,947
Repurchase Agreements, Financial Assets, Gross Amount Recognized	0	0
Repurchase Agreements And Securities Loaned, Asset	0	0
Repurchase Agreements, Financial Assets, Net Amount Recognized	0	0
Repurchase Agreements, Financial Liabilities, Gross Amount Recognized	312,239	232,789
Repurchase Agreements, Financial Liabilities, Gross Amount Offset	0	0
Repurchase Agreements, Financial Liabilities, Net Amount Recognized	312,239	232,789
Total Financial Assets, Gross Amount Recognized	29,458	17,540
Total Financial Assets, Gross Amount Offset	0	0
Total Financial Assets, Net Amount Recognized	29,458	17,540
Total Financial Liabilities, Gross Amount Recognized	334,172	260,736
Total Financial Liabilities, Gross Amount Offset	0	0
Total Financial Liabilities, Net Amount Recognized	334,172	260,736
Interest rate swaps, caps and floors
Derivative [Line Items]
Financial Assets, Gross Amount Recognized	18,791	11,659
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	18,791	11,659
Financial Liabilities, Gross Amount Recognized	15,098	11,562
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	15,098	11,562
Foreign exchange contracts
Derivative [Line Items]
Financial Assets, Gross Amount Recognized	896	1,013
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	896	1,013
Financial Liabilities, Gross Amount Recognized	540	953
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	540	953
Mortgage related derivatives
Derivative [Line Items]
Financial Assets, Gross Amount Recognized	9,771	4,868
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	9,771	4,868
Financial Liabilities, Gross Amount Recognized	6,295	15,432
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	$ 6,295	$ 15,432

Derivative Financial Instrume_5

Derivative Financial Instruments - Instruments Eligible for Offset by Counterparty (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Financial Assets, Net Amount Recognized	$ 29,458	$ 17,540
Financial Assets, Financial Instruments	(21,456)	(14,719)
Financial Assets, Collateral	(7,824)	0
Financial Assets, Net Amount	178	2,821
Financial Liabilities, Net Amount Recognized	21,933	27,947
Financial Liabilities, Financial Instruments	(21,456)	(14,719)
Financial Liabilities, Collateral	(358)	(13,223)
Financial Liabilities, Net Amount	119	5
Repurchase Agreements, Financial Assets, Net Amount Recognized	0	0
Repurchase Agreements, Financial Assets, Financial Instruments	0	0
Repurchase Agreements, Financial Assets, Collateral	0	0
Repurchase Agreements, Financial Assets, Net Amount	0	0
Repurchase Agreements, Financial Liabilities, Net Amount Recognized	312,239	232,789
Repurchase Agreements, Financial Liabilities, Financial Instruments	0	0
Repurchase Agreements, Financial Liabilities, Collateral	(312,239)	(232,789)
Repurchase Agreements, Financial Liabilities, Net Amount	0	0
Total Financial Assets, Net Amount Recognized	29,458	17,540
Total Financial Assets, Financial Instruments	(21,456)	(14,719)
Total Financial Assets, Collateral	(7,824)	0
Total Financial Assets, Net Amount	178	2,821
Total Financial Liabilities, Net Amount Recognized	334,172	260,736
Total Financial Liabilities, Financial Instruments	(21,456)	(14,719)
Total Financial Liabilities, Collateral	(312,597)	(246,012)
Total Financial Liabilities, Net Amount	119	5
Counterparty A
Derivative [Line Items]
Financial Assets, Net Amount Recognized	6,046	6,068
Financial Assets, Financial Instruments	(3,993)	(6,068)
Financial Assets, Collateral	(2,053)	0
Financial Assets, Net Amount	0	0
Financial Liabilities, Net Amount Recognized	3,993	13,807
Financial Liabilities, Financial Instruments	(3,993)	(6,068)
Financial Liabilities, Collateral	0	(7,739)
Financial Liabilities, Net Amount	0	0
Counterparty B
Derivative [Line Items]
Financial Assets, Net Amount Recognized	1,234	3,261
Financial Assets, Financial Instruments	(151)	(3,261)
Financial Assets, Collateral	(1,083)	0
Financial Assets, Net Amount	0	0
Financial Liabilities, Net Amount Recognized	151	5,595
Financial Liabilities, Financial Instruments	(151)	(3,261)
Financial Liabilities, Collateral	0	(2,334)
Financial Liabilities, Net Amount	0	0
Counterparty C
Derivative [Line Items]
Financial Assets, Net Amount Recognized	1,660	5,285
Financial Assets, Financial Instruments	(713)	(3,640)
Financial Assets, Collateral	(947)	0
Financial Assets, Net Amount	0	1,645
Financial Liabilities, Net Amount Recognized	713	3,640
Financial Liabilities, Financial Instruments	(713)	(3,640)
Financial Liabilities, Collateral	0	0
Financial Liabilities, Net Amount	0	0
Other counterparties
Derivative [Line Items]
Financial Assets, Net Amount Recognized	20,518	2,926
Financial Assets, Financial Instruments	(16,599)	(1,750)
Financial Assets, Collateral	(3,741)	0
Financial Assets, Net Amount	178	1,176
Financial Liabilities, Net Amount Recognized	17,076	4,905
Financial Liabilities, Financial Instruments	(16,599)	(1,750)
Financial Liabilities, Collateral	(358)	(3,150)
Financial Liabilities, Net Amount	$ 119	$ 5

Operating Segments (Details)

Operating Segments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	3
Segment Reporting Information [Line Items]
Net interest income	$ 637,803	$ 602,377	$ 517,891
Provision for credit losses	47,201	21,593	19,563
Non-interest income	342,629	369,374	378,150
Non-interest expense	681,060	661,343	623,098
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	252,171	288,815	253,380
Income tax expense (benefit)	38,256	(15,225)	79,244
Net income	213,915	304,040	174,136
Total assets	$ 20,207,026	20,086,940	19,302,317
Current Fiscal Year End Date	--12-31
Banking
Segment Reporting Information [Line Items]
Net interest income	$ 592,514	550,499	475,133
Provision for credit losses	46,104	16,555	18,583
Non-interest income	179,136	174,120	153,250
Non-interest expense	486,212	462,055	421,733
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	239,334	246,009	188,067
Income tax expense (benefit)	38,602	65,137	53,263
Net income	200,732	180,872	134,804
Total assets	17,070,713	16,448,960	16,368,881
Merger expenses, banking segment	32,400
Leasing
Segment Reporting Information [Line Items]
Net interest income	9,563	9,902	9,415
Provision for credit losses	1,204	3,858	295
Non-interest income	100,140	86,029	73,503
Non-interest expense	63,897	57,331	48,450
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	44,602	34,742	34,173
Income tax expense (benefit)	8,158	(51,140)	13,525
Net income	36,444	85,882	20,648
Total assets	1,464,380	1,403,690	1,224,169
Mortgage Banking
Segment Reporting Information [Line Items]
Net interest income	35,726	41,976	33,343
Provision for credit losses	(107)	1,180	685
Non-interest income	63,353	109,225	151,397
Non-interest expense	130,951	141,957	152,915
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	(31,765)	8,064	31,140
Income tax expense (benefit)	(8,504)	(29,222)	12,456
Net income	(23,261)	37,286	18,684
Total assets	1,671,933	2,234,290	1,709,267
Taylor Capital Group, Inc. | Banking
Segment Reporting Information [Line Items]
Merger expenses, banking segment	$ 15,100	$ 9,900	$ 23,700

Condensed Parent Company Fina_3

Condensed Parent Company Financial Information - Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash	$ 650,407	$ 579,221	$ 463,469	$ 381,441
Other assets	445,994	420,810
Total assets	20,207,026	20,086,940	19,302,317
Liabilities and Stockholders’ Equity
Short-term borrowings	1,470,055	861,039
Long-term borrowings	349,681	505,158
Junior subordinated notes issued to capital trusts	121,118	211,494
Other liabilities	577,111	541,048
Total stockholders’ equity	3,034,848	3,009,823	2,579,209	2,087,284
Total liabilities and stockholders’ equity	20,207,026	20,086,940
MB Financial, Inc.
Assets
Cash	106,808	219,086	$ 26,591	$ 104,819
Investments in subsidiaries	2,990,651	2,961,822
Other assets	85,291	73,438
Total assets	3,182,750	3,254,346
Liabilities and Stockholders’ Equity
Short-term borrowings	0	0
Long-term borrowings	0	10,000
Junior subordinated notes issued to capital trusts	121,118	211,494
Other liabilities	26,784	23,029
Total stockholders’ equity	3,034,848	3,009,823
Total liabilities and stockholders’ equity	$ 3,182,750	$ 3,254,346

Condensed Parent Company Fina_4

Condensed Parent Company Financial Information - Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Parent Company Financial Information
Income before income taxes	$ 252,171	$ 288,815	$ 253,380
Income tax benefit	38,256	(15,225)	79,244
Net income	213,915	304,040	174,136
Dividends on preferred shares	12,100	8,007	8,009
Preferred Stock Redemption Discount	15,280	0	0
Net income available to common stockholders	217,095	296,033	166,127
MB Financial, Inc.
Condensed Parent Company Financial Information
Dividends from subsidiaries	200,000	78,846	112,000
Interest and other income	(908)	4,148	1,913
Interest and other expense	29,167	18,990	14,990
Income before income taxes	169,925	64,004	98,923
Income tax benefit	(8,045)	(8,253)	(5,303)
Income before equity in undistributed net income of subsidiaries	177,970	72,257	104,226
Equity in undistributed net income of subsidiaries	35,945	231,783	69,910
Net income	213,915	304,040	174,136
Dividends on preferred shares	12,100	8,007	8,009
Preferred Stock Redemption Discount	(15,280)	0	0
Net income available to common stockholders	$ 217,095	$ 296,033	$ 166,127

Condensed Parent Company Fina_5

Condensed Parent Company Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows From Operating Activities
Net income	$ 213,915	$ 304,040	$ 174,136
Adjustments to reconcile net income to net cash provided by operating activities:
Compensation expense for share-based payment plans	18,727	17,476	16,868
Gain (Loss) on Extinguishment of Debt	11,898	0	0
Cash Flows From Investing Activities
Investments in and advances to subsidiaries	0	(827)	(2,336)
Net cash paid in business acquisition	0	(3,780)	(9,010)
Net cash used in investing activities	(623,686)	(907,856)	(727,654)
Cash Flows From Financing Activities
Treasury stock transactions, net	(1,685)	(3,271)	(3,837)
Stock options exercised	4,063	2,504	1,410
Dividends paid on common stock	(81,883)	(69,346)	(58,177)
Dividends paid on preferred stock	(14,100)	(8,007)	(8,009)
Issuance of preferred stock, net of issuance costs	0	194,719	0
Principal paid on long-term borrowings	(272,542)	(114,129)	(71,845)
Redemption of junior subordinated notes issued to capital trusts	103,096	0	0
Net cash (used in) provided by financing activities	(147,327)	449,648	558,053
Net increase in cash and cash equivalents	71,186	115,752	82,028
Cash:
Beginning of year	579,221	463,469	381,441
End of year	650,407	579,221	463,469
MB Financial, Inc.
Cash Flows From Operating Activities
Net income	213,915	304,040	174,136
Adjustments to reconcile net income to net cash provided by operating activities:
Compensation expense for share-based payment plans	18,727	17,476	16,868
Equity in undistributed net income of subsidiaries	(35,945)	(231,783)	(69,910)
Gain (Loss) on Extinguishment of Debt	11,898	0	0
Change in other assets and other liabilities	(14,172)	163	(28,546)
Net cash provided by operating activities	194,423	89,896	92,548
Cash Flows From Investing Activities
Investments in and advances to subsidiaries	0	0	(2,000)
Net cash paid in business acquisition	0	0	(83,163)
Net cash used in investing activities	0	0	(85,163)
Cash Flows From Financing Activities
Treasury stock transactions, net	(1,685)	(3,271)	(3,837)
Stock options exercised	4,063	2,504	1,410
Dividends paid on common stock	(81,883)	(69,346)	(58,177)
Dividends paid on preferred stock	(14,100)	(8,007)	(8,009)
Issuance of preferred stock, net of issuance costs	0	194,719	0
Redemption of preferred stock	100,000	0	0
Net decrease short-term borrowings	0	(10,000)	(15,000)
Principal paid on long-term borrowings	(10,000)	(4,000)	(2,000)
Redemption of junior subordinated notes issued to capital trusts	103,096	0	0
Net cash (used in) provided by financing activities	(306,701)	102,599	(85,613)
Net increase in cash and cash equivalents	(112,278)	192,495	(78,228)
Cash:
Beginning of year	219,086	26,591	104,819
End of year	$ 106,808	$ 219,086	$ 26,591

Preferred Stock (Details)

Preferred Stock (Details) $ / shares in Units, $ in Thousands	Feb. 15, 2018USD ($)$ / sharesshares	Nov. 22, 2017$ / sharesshares	Sep. 20, 2017shares	Aug. 24, 2016$ / sharesshares	Nov. 20, 2015	Aug. 18, 2014shares	Sep. 30, 2016shares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017$ / sharesshares
Class of Stock [Line Items]
Stock Redeemed or Called During Period, Value | $								$ 100,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares) | shares								0	4,000,000
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares								$ 25	$ 25
Preferred stock, dividend rate (percent)								8.00%	8.00%
Stock Redeemed or Called During Period, Shares | shares	4,000,000
Depositary share, liquidation preference per share (in dollars per share) | $ / shares	$ 25
Stock Redeemed or Called During Period, Value | $	$ 100,000
Preferred Stock Redemption Premium | $	$ 15,300
Series A Preferred Stock | Taylor Capital Group, Inc.
Class of Stock [Line Items]
Equity conversion ratio						1
Preferred stock, shares outstanding (in shares) | shares						4,000,000
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares								$ 25
Preferred stock, dividend rate (percent)						8.00%
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares) | shares								0	0
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares								$ 1,000	$ 1,000
Preferred stock, dividend rate (percent)					8.00%			8.00%	8.00%
Series B Preferred Stock | American Chartered Merger
Class of Stock [Line Items]
Equity conversion ratio				1
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares				$ 1,000
Preferred stock, dividend rate (percent)				8.00%
Conversion preferred stock to common stock in (in shares) | shares			125				400
Series D Preferred Stock | American Chartered Merger
Class of Stock [Line Items]
Preferred stock, shares outstanding (in shares) | shares				525
Series C Preferred Stock, Depository Shares
Class of Stock [Line Items]
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares		$ 25
Preferred stock, dividend rate (percent)		6.00%
Shares issued | shares		8,000,000
Interest in preferred stock for each depositary share (in dollars per share)		0.025%
Depositary share, liquidation preference per share (in dollars per share) | $ / shares		$ 25

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event $ in Millions	Feb. 06, 2019USD ($)
Subsequent Event [Line Items]
Payments For FDIC Loss Share Agreements	$ 15.9
Gain (Loss) On Loss Share Agreement	5
Loans Not Covered Under the FDIC Loss Share Agreement	$ 12.1

Definitive Merger Agreement (De

Definitive Merger Agreement (Details) - Merger With Fifth Third Bancorp [Member]	May 20, 2018$ / sharesshares
Business Acquisition [Line Items]
Number of shares called by each right (in shares) | shares	1.45
Cash paid per share (in dollars per share) | $ / shares	$ 5.54

Uncategorized Items - mbfi-2018

Label	Element	Value
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (1,204,000)