MB Financial 10-K 21 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Feb. 19, 2014	Jun. 30, 2013
Document and Entity Information	'	'	'
Entity Registrant Name	'MB FINANCIAL INC /MD	'	'
Entity Central Index Key	'0001139812	'	'
Document Type	'10-K	'	'
Document Period End Date	31-Dec-13	'	'
Amendment Flag	'false	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$1,421,825,010
Entity Common Stock, Shares Outstanding	'	54,962,647	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Assets	'		'
Cash and due from banks	$205,193		$176,010
Interest earning deposits with banks	268,266		111,533
Total cash and cash equivalents	473,459		287,543
Federal funds sold	42,950		0
Investment securities:	'		'
Securities available for sale, at fair value	1,118,912		1,868,171
Securities held to maturity, at amortized cost ($1.2 billion and $0.5 billion fair value at December 31, 2013 and 2012, respectively)	1,182,533		493,421
Non-marketable securities - FHLB and FRB stock	51,417		55,385
Total investment securities	2,352,862		2,416,977
Loans held for sale	629		7,492
Loans:	'		'
Total loans, excluding covered loans	5,476,831		5,317,080
Covered loans	235,720		449,850
Total loans	5,712,551	[1]	5,766,930	[1]
Less: Allowance for loan losses	111,746		124,204
Net loans	5,600,805		5,642,726
Lease investment, net	131,089		129,823
Premises and equipment, net	221,065		221,533
Cash surrender value of life insurance	130,181		128,879
Goodwill	423,369		423,369
Other intangibles	23,428		29,512
Other real estate owned, net	23,289		36,977
Other real estate owned related to FDIC-assisted transactions	20,472		22,478
FDIC indemnification asset	11,675		39,345
Other assets	186,154		185,151
Total assets	9,641,427		9,571,805
Deposits:	'		'
Noninterest bearing	2,375,863		2,164,547
Interest bearing	5,005,396		5,378,150
Total	7,381,259		7,542,697
Short-term borrowings	493,389		220,602
Long-term borrowings	62,159		116,050
Junior subordinated notes issued to capital trusts	152,065		152,065
Accrued expenses and other liabilities	225,873		264,621
Total liabilities	8,314,745		8,296,035
STOCKHOLDERS’ EQUITY	'		'
Common stock, ($0.01 par value; authorized 70,000,000 shares at December 31, 2013 and 2012; issued 55,148,409 and 54,955,284 shares at December 31, 2013 and 2012, respectively)	551		550
Additional paid-in capital	738,053		732,771
Retained earnings	581,998		507,933
Accumulated other comprehensive income	8,383		36,326
Less: 184,173 and 170,567 shares of treasury stock, at cost, at December 31, 2013 and 2012, respectively	-3,747		-3,293
Controlling interest stockholders’ equity	1,325,238		1,274,287
Noncontrolling interest	1,444		1,483
Total stockholders’ equity	1,326,682		1,275,770
Total liabilities and stockholders’ equity	$9,641,427		$9,571,805
[1]	Gross loan balances at December 31, 2013 and 2012 are net of unearned income, including net deferred loan fees of $1.9 million and $1.1 million, respectively.

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Securities held to maturity, at amortized cost, fair value (in dollars)	$1,198,929	$535,681
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, authorized shares	70,000,000	70,000,000
Common stock, issued shares	55,148,409	54,955,284
Treasury stock, shares	184,173	170,567

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Interest income:	'	'	'
Loans	$238,542	$271,708	$324,793
Investment securities:	'	'	'
Taxable	26,084	33,424	41,349
Nontaxable	32,564	29,311	17,265
Federal funds sold	15	'	'
Other interest earning accounts	690	867	1,153
Total interest income	297,895	335,310	384,560
Interest expense:	'	'	'
Deposits	19,240	30,258	44,881
Short-term borrowings	622	1,204	849
Long-term borrowings and junior subordinated notes	5,697	11,060	13,557
Total interest expense	25,559	42,522	59,287
Net interest income	272,336	292,788	325,273
Provision for credit losses	-5,804	-8,900	120,750
Net interest income after provision for credit losses	278,140	301,688	204,523
Non-interest income:	'	'	'
Capital markets and international banking fees	3,560	5,086	1,870
Commercial deposit and treasury management fees	24,867	23,636	23,559
Lease financing, net	61,243	36,382	26,939
Trust and asset management fees	19,142	17,990	17,324
Card fees	11,013	9,368	7,032
Loan service fees	5,563	5,845	6,355
Consumer and other deposit service fees	13,968	14,428	15,375
Brokerage fees	4,907	4,792	5,884
Net (loss) gain on investment securities	-1	555	640
Increase in cash surrender value of life insurance	3,385	3,570	4,377
Net (loss) gain on sale of assets	-323	-942	283
Accretion of FDIC indemnification asset	342	1,055	4,838
Net gain on sale of loans	1,664	2,325	2,607
Other operating income	5,064	5,103	5,636
Total non-interest income	154,394	129,193	122,719
Non-interest expenses:	'	'	'
Salaries and employee benefits	177,858	165,696	153,858
Occupancy and equipment expense	36,878	35,806	35,467
Computer services and telecommunication expense	18,883	15,499	14,885
Advertising and marketing expense	8,272	8,183	7,038
Professional and legal expense	8,807	6,110	6,147
Other intangibles amortization expense	6,084	5,010	5,665
Branch impairment charges	'	2,190	1,594
Net (gain) loss recognized on other real estate owned	-1,528	17,594	13,613
Other real estate expense, net	747	2,990	4,294
Prepayment fees on interest bearing liabilities	'	12,682	'
Other operating expenses	38,587	32,270	40,685
Total non-interest expenses	294,588	304,030	283,246
Income before income taxes	137,946	126,851	43,996
Income tax expense	39,491	36,477	5,268
Net income	98,455	90,374	38,728
Dividends and discount accretion on preferred shares	'	3,269	10,414
Net income available to common stockholders	$98,455	$87,105	$28,314
Common share data:	'	'	'
Basic earnings per common share	$1.81	$1.61	$0.52
Diluted earnings per common share	$1.79	$1.60	$0.52
Diluted weighted average common shares outstanding for diluted earnings per common share	54,993,865	54,505,976	54,337,280

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Other Comprehensive Income [Abstract]	'	'	'
Net income	$98,455	$90,374	$38,728
Unrealized holding (losses) gains on investment securities, net of reclassification adjustments	-43,543	-4,097	28,501
Reclassification adjustment for amortization of unrealized gains on investment securities transferred to held to maturity from available for sale	-2,478	0	0
Reclassification adjustments for losses (gains) included in net income	1	-555	-640
Other comprehensive (loss) income, before tax	-46,020	-4,652	27,861
Income tax benefit (expense) related to items of other comprehensive (loss) income	18,077	1,828	-10,944
Other comprehensive (loss) income, net of tax	-27,943	-2,824	16,917
Comprehensive income	$70,512	$87,550	$55,645

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $)	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net of Tax	Treasury Stock	Noncontrolling Interest
In Thousands, unless otherwise specified
Balance at Dec. 31, 2010	$1,344,786	$194,104	$546	$725,400	$402,810	$22,233	($2,828)	$2,521
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	38,967	'	'	'	38,728	'	'	239
Other comprehensive income (loss), net of tax	16,917	'	'	'	'	16,917	'	'
Cash dividends declared on common stock	-2,185	'	'	'	-2,185	'	'	'
Dividends and discount accretion on preferred shares	-9,799	615	'	'	-10,414	'	'	'
Restricted common stock activity, net of tax	-156	'	1	-157	-968	'	968	'
Stock option activity, net of tax	1,193	'	1	1,103	-15	'	104	'
Issuance of shares of common stock, net of issuance costs	16	'	'	16	'	'	'	'
Repurchase of common shares in connection with employee benefit plans and held in trust for deferred compensation plan	-1,238	'	'	50	'	'	-1,288	'
Stock-based compensation expense	4,836	'	'	4,836	'	'	'	'
Distributions to noncontrolling interest	-310	'	'	'	'	'	'	-310
Balance at Dec. 31, 2011	1,393,027	194,719	548	731,248	427,956	39,150	-3,044	2,450
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	90,604	'	'	'	90,374	'	'	230
Other comprehensive income (loss), net of tax	-2,824	'	'	'	'	-2,824	'	'
Cash dividends declared on common stock	-7,149	'	'	'	-7,149	'	'	'
Dividends and discount accretion on preferred shares	-1,988	1,281	'	'	-3,269	'	'	'
Repurchase of preferred shares and warrant	-197,518	-196,000	'	-1,518	'	'	'	'
Restricted common stock activity, net of tax	1,090	'	2	-704	18	'	1,774	'
Stock option activity, net of tax	-346	'	'	-694	3	'	345	'
Repurchase of common shares in connection with employee benefit plans and held in trust for deferred compensation plan	-1,999	'	'	369	'	'	-2,368	'
Stock-based compensation expense	4,806	'	'	4,806	'	'	'	'
Additional investment in subsidiary	-1,640	'	'	-736	'	'	'	-904
Distributions to noncontrolling interest	-293	'	'	'	'	'	'	-293
Balance at Dec. 31, 2012	1,275,770	0	550	732,771	507,933	36,326	-3,293	1,483
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'	'
Net income	98,641	'	'	'	98,455	'	'	186
Other comprehensive income (loss), net of tax	-27,943	'	'	'	'	-27,943	'	'
Cash dividends declared on common stock	-24,290	'	'	'	-24,290	'	'	'
Restricted common stock activity, net of tax	887	'	1	-739	-100	'	1,725	'
Stock option activity, net of tax	557	'	'	58	'	'	499	'
Repurchase of common shares in connection with employee benefit plans and held in trust for deferred compensation plan	-2,171	'	'	507	'	'	-2,678	'
Stock-based compensation expense	5,456	'	'	5,456	'	'	'	'
Distributions to noncontrolling interest	-225	'	'	'	'	'	'	-225
Balance at Dec. 31, 2013	$1,326,682	$0	$551	$738,053	$581,998	$8,383	($3,747)	$1,444

CONSOLIDATED_STATEMENTS_OF_CHA1

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Stockholders' Equity [Abstract]	'	'	'
Cash dividends declared	$0.44	$0.13	$0.04

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities	'	'	'
Net income	$98,455	$90,374	$38,728
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'
Depreciation of premises and equipment	18,051	16,273	13,577
Depreciation of leased equipment	33,842	36,146	42,390
Impairment charges on branch facilities	'	2,190	1,594
Compensation expense for restricted stock awards	4,280	3,544	3,277
Compensation expense for stock option grants	1,176	1,262	1,559
Loss (gain) on sales of premises and equipment and leased equipment	362	-2,204	-1,923
Amortization of other intangibles	6,084	5,010	5,665
Provision for credit losses	-5,804	-8,900	120,750
Deferred income tax expense	21,681	15,177	5,166
Amortization of premiums and discounts on investment securities, net	47,771	44,543	40,894
Accretion of premiums and discounts on loans, net	-7,122	-13,797	-30,329
Accretion of FDIC indemnification asset	-342	-1,055	-4,838
Net loss (gain) on investment securities	1	-555	-640
Proceeds from sale of loans held for sale	86,505	96,243	47,128
Origination of loans held for sale	-77,935	-96,480	-51,038
Net gain on sale of loans held for sale	-1,664	-2,325	-2,607
Net gain on sales of other real estate owned	-1,984	-1,398	-1,016
Fair value adjustments on other real estate owned	96	15,901	10,988
Net loss on sales of other real estate owned related to FDIC-assisted transactions	360	3,091	3,641
Increase in cash surrender value of life insurance	-3,385	-3,570	-4,377
Decrease (increase) in other assets, net	17,485	-67,511	8,393
(Decrease) increase in other liabilities, net	-45,155	49,861	25,599
Net cash provided by operating activities	192,758	181,820	272,581
Cash Flows From Investing Activities	'	'	'
Increase in federal funds sold	-42,950	0	0
Proceeds from sales of investment securities available for sale	989	15,416	22,960
Proceeds from maturities and calls of investment securities available for sale	496,258	608,665	406,154
Purchase of investment securities available for sale	-484,113	-605,098	-769,897
Proceeds from maturities and calls of investment securities held to maturity	17,087	2,134	543
Purchase of investment securities held to maturity	-61,073	-2,187	-501,464
Purchase of non-marketable securities - FHLB and FRB stock	-547	-44	-646
Redemption of non-marketable securities - FHLB and FRB stock	4,515	25,491	0
Net decrease in loans	38,725	219,125	189,630
Proceeds from sale of loans held for sale	'	'	207,530
Purchases of premises and equipment	-18,345	-30,926	-18,030
Purchases of leased equipment	-47,108	-45,749	-59,764
Purchases of premises and equipment	'	1,516	1,483
Proceeds from sales of leased equipment	8,532	13,071	8,041
Capital improvements on other real estate owned	-74	-2,809	-1,534
Proceeds from sale of other real estate owned	21,814	34,316	43,847
Proceeds from sale of other real estate owned related to FDIC-assisted transactions	15,194	40,298	26,932
Life insurance death benefit	2,083	'	4,114
Net cash paid in acquisition	0	-27,010	0
Net proceeds from FDIC related covered assets	9,766	83,954	152,238
Net cash (used in) provided by investing activities	-39,247	330,163	-287,863
Cash Flows From Financing Activities	'	'	'
Net decrease in deposits	-161,438	-104,910	-505,351
Net increase (decrease) in short-term borrowings	272,787	648	-48,890
Proceeds from long-term borrowings	7,725	6,742	14,854
Principal paid on long-term borrowings	-61,616	-156,956	-33,663
Redemption of junior subordinated notes issued to capital trusts	0	-6,186	0
Repurchase of preferred stock and warrant	0	-197,518	0
Treasury stock transactions, net	-1,672	-249	-1,149
Stock options exercised	1,014	154	1,903
Excess tax benefits from share-based payment arrangements	-325	-390	-53
Dividends paid on preferred stock	'	-3,239	-9,799
Dividends paid on common stock	-24,070	-7,101	-2,164
Net cash provided by (used in) financing activities	32,405	-469,005	-584,312
Net increase (decrease) in cash and cash equivalents	185,916	42,978	-599,594
Cash and cash equivalents:	'	'	'
Beginning of year	287,543	244,565	844,159
End of year	473,459	287,543	244,565
Cash payments for:	'	'	'
Interest paid to depositors and other borrowed funds	26,345	44,212	61,098
Net income tax payments (refunds), net	35,375	9,883	-7,015
Supplemental Schedule of Noncash Investing Activities:	'	'	'
Investment securities held to maturity purchased not settled	321	0	0
Transfer of investment securities available for sale to investment securities held to maturity	656,617	0	0
Loans transferred to other real estate owned	6,164	4,535	59,261
Loans transferred to other real estate owned related to FDIC-assisted transactions	16,023	19,705	59,973
Loans transferred to repossessed vehicles	871	1,496	1,281
Loans transferred to loans held for sale	'	'	205,740
Operating leases rewritten as direct finance leases included as loans	6,936	7,760	3,068
Reclassification of reserves on unfunded credit commitments	'	'	17,050
Noncash assets acquired:	'	'	'
Investment securities available for sale	'	635	'
Loans and leases	'	32,933	'
Premises and equipment	'	81	'
Goodwill	0	36,300	'
Other intangibles	'	5,028	'
Other assets	'	27,323	'
Total noncash assets acquired	0	102,300	0
Liabilities assumed:	'	'	'
Accrued expenses and other liabilities	'	75,290	'
Total liabilities assumed	0	75,290	0
Net noncash assets acquired	0	27,010	0
Net cash and cash equivalents paid	'	-27,010	'
Net gains recorded on acquisitions	$0	$0	$0

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
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 84 banking offices through MB Financial Bank.
	MB Financial Bank, our largest subsidiary, has two wholly owned subsidiaries with significant operating activities: LaSalle Systems Leasing, Inc. and Celtic Leasing Corp. MB Financial Bank also has a majority owned subsidiary with significant operating activities, Cedar Hill Associates, LLC. Vision Investment Services, Inc., a subsidiary of MB Financial Bank, was dissolved in the fourth quarter of 2012.
	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 losses; residual value of direct finance, leveraged, and operating leases; 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.  Gains and losses recognized on mortgage loans held for sale include the value of the mortgage servicing rights if the loan is sold with servicing retained by the Company.  Mortgage servicing rights are stratified based on the predominant risk characteristics of rates, terms, and the underlying loan types to measure its fair value.  The amount of impairment recognized is the amount by which the capitalized mortgage servicing rights for a stratum exceed their fair value.
	Loans and leases: Loans are stated at the amount of unpaid principal reduced by the allowance for loan 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 at the sum of remaining minimum lease payments from lessees (less nonrecourse debt payments) plus estimated residual values less unearned lease income.  On a quarterly 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 nonaccrual loans and loans classified as a troubled debt restructuring. 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 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.
	Periodically, the Company will restructure a note into two separate notes (A/B structure), charging off the entire B portion of the note. The A note is structured with appropriate loan-to-value and cash flow coverage ratios that provide for a high likelihood of repayment. The A note is classified as a non-performing note until the borrower has displayed a historical payment performance for a reasonable time prior to and subsequent to the restructuring. A period of sustained repayment for at least six months generally is required to return the note to accrual status provided that management has determined that the performance is reasonably expected to continue. The A note will be classified as a restructured note (either performing or nonperforming) through the calendar year of the restructuring that the historical payment performance has been established.
	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, and prevailing economic conditions that may affect the borrower’s ability to pay.  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 any loan committee.  Loans rated "one" represent those loans least likely to default and 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 the migration of loan risk ratings and historical default data over a multi-year period to develop our estimated default factors (EDFs).  The model tracks annual loan rating migrations by loan type and currently uses loan risk rating migrations for 13 years.  The migration data is adjusted by using average losses for an economic cycle (approximately 12 years) to develop EDFs by loan type, risk rating and maturity.  EDFs are updated annually in December.
	Estimated loan default factors are multiplied by individual loan balances in each risk-rating category and again multiplied by an historical loss given default estimate for each loan type (which incorporates estimated 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 adjustments for macroeconomic factors.  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 has shown to be a statistically reliable predictor of our credit losses relative to our long term average credit losses. We tested over 20 economic variables (U.S. manufacturing index, unemployment rate, U.S. GDP growth, etc.). We annually review this data to determine that such a relationship continues to exist. We currently use the following macroeconomic indicators in our macroeconomic factor computation:
	Commercial loans and lease loans:  Japanese bilateral dollar exchange, our prior period charge-off rates and the consumer confidence index.
	Commercial real estate loans and construction loans:  Prime rate, our prior period charge-off rates and the annual change in the U.S. commercial real estate index.
	Using the indicators noted above, a predicted charge-off percentage is calculated.  The predicted charge-off percentage is then compared to the cycle average charge-off percentage used in our EDF computation discussed above, and a macroeconomic adjustment factor is calculated.  The macroeconomic adjustment factor is applied to each commercial loan type.  Each year, we review the predictive nature of the macroeconomic factors by comparing actual charge-offs to the predicted model charge-offs, re-run our regression analysis and re-calibrate the macroeconomic factors as appropriate.
	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, most recently updated in December 2010. 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 by internally applying accepted appraisal methodologies to an older appraisal.  Accepted appraisal methodologies include:  income capitalization approach adjusting for changes in underlying leases, adjustments related to condominium projects with units sales, adjustments for loan fundings, and “As is” compared to “As Stabilized” valuations.
	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 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 losses: historical net charge-offs as they relate to prior periods' allowance for loan loss, comparison of historical loan migration in past years compared to the current year, overall credit trends and ratios and any significant changes in loan concentrations. 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 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 310-20 “Nonrefundable Fees and Other Costs” as these loans do not have evidence of credit deterioration since origination.
	•	Non-impaired loans (typically past-due loans, special mention loans and performing substandard loans) are accounted for in accordance with ASC 310-30 “Receivables - Loans and Debt Securities Acquired with Deteriorated Credit Quality” as 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 310-30 as they display significant credit deterioration since origination.
	In accordance with ASC 310-30, for both purchased non-impaired loans and purchased impaired loans, the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. This amount is not recognized as a yield adjustment or as a loss accrual or a valuation allowance. 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 when there is a reasonable expectation about the amount and timing of such cash flows.
	Increases in expected cash flows subsequent to the initial investment are recognized prospectively through adjustment of the yield net of any impact of the loss share agreement with the FDIC, if applicable, on the loan over its remaining estimated life. Decreases in expected cash flows are recognized immediately as impairment. If the Company does not have the information necessary to reasonably estimate cash flows to be expected, it may use the cost recovery method or cash basis method of income recognition. Valuation allowances on these impaired loans reflect only losses incurred after the acquisition (meaning the present value of all cash flows expected at acquisition that ultimately are not to be received).
	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 range from 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.
	Other real estate owned (OREO): OREO includes real estate assets that have been received in satisfaction of debt.  OREO is initially recorded at fair value less estimated selling costs, which establishes the cost basis.  Subsequently, OREO 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 losses.  Subsequently, unrealized losses and realized gains and losses on sale are included in net loss recognized on other real estate owned.  Operating results from OREO are recorded separately on the income statement within other real estate expense, net.
	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 at the unit level. As of December 31, 2013, the annual assessment date, the Company had two reporting units: banking and leasing. The Company did not recognize impairment losses during the year ended December 31, 2013.
	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 the declining balance method over four to 15 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.
	FDIC indemnification asset: As part of the Heritage, Benchmark, Broadway, and New Century transactions, MB Financial Bank entered into loss-share agreements with the FDIC. These agreements cover realized losses on loans and foreclosed real estate. 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 separately on the balance sheet.  The corresponding accretion is recorded separately on the income statement.  Although these assets are contractual receivables from the FDIC, there are no contractual interest rates.
	When cash flow estimates are adjusted downward for a particular loan pool, the FDIC indemnification asset is increased.  An allowance for loan losses is established for the impairment of the loans.  A provision for loan losses is recognized for the difference between the increase in the FDIC indemnification asset and the decrease in cash flows.
	When cash flow estimates are adjusted upward for a particular loan pool, the FDIC indemnification asset is decreased.  The difference between the decrease in the FDIC indemnification asset and the increase in cash flows is accreted over the estimated life of the loan pool.
	When cash flow estimates are adjusted downward for covered foreclosed real estate, the FDIC indemnification asset is increased.  A charge is recognized for the difference between the increase in the FDIC indemnification asset and the decrease in cash flows.
	When cash flow estimates are adjusted upward for covered foreclosed real estate, the FDIC indemnification asset is decreased.  Any write-down after the transfer to covered foreclosed real estate is reversed.
	In both scenarios, the claw-back liability will increase or decrease accordingly.
	Preferred stock: Preferred stock callable at the option of the Company is initially recorded at the amount of proceeds received.  Any discount from the liquidation value is accreted to the expected call date and charged to retained earnings.  This accretion is recorded using the level-yield method.  Preferred dividends paid (declared and accrued) and any accretion is deducted from net income for computing income available to common stockholders and earnings per 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 income statement, and requires that a company must 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 income statement 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 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: LaSalle Business Solutions, LLC (LBS), a subsidiary of LaSalle Systems Leasing, Inc., sells third party maintenance contracts to customers.  The maintenance is serviced by third party providers, with LBS maintaining no legal obligation under the contract to perform additional services.  Revenues are recorded net of cost of sales, as LBS is viewed as an agent under ASC Topic 605, 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: 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: The Company accounts for its equity awards in accordance with ASC Topic 718.  ASC Topic 718 requires public companies to recognize compensation expense related to stock-based equity awards in their income statements.  See Note 19 below for more information.
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: 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.
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,
		2013		2012		2011
Distributed earnings allocated to common stock		$	24,290	$	7,149	$	2,185
Undistributed earnings		74,165		83,225		36,543
Net income		98,455		90,374		38,728
Less: preferred stock dividends and discount accretion		—		3,269		10,414
Net income available to common stockholders		98,455		87,105		28,314
Less: earnings and dividends allocated to participating securities		2		3		33
Earnings allocated to common stockholders		$	98,453	$	87,102	$	28,281
Weighted average shares outstanding for basic earnings per common share		54,509,612		54,270,297		54,057,158
Dilutive effect of equity awards		484,253		235,679		280,122
Weighted average shares outstanding for diluted earnings per common share		54,993,865		54,505,976		54,337,280
Basic earnings per common share		$	1.81	$	1.61	$	0.52
Diluted earnings per common share		1.79		1.6		0.52
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: An operating segment is a component of an entity: (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. As of December 31, 2013, the Company had two reportable operating segments: banking and leasing.
New authoritative accounting guidance:
ASC Topic 805 “Business Combinations.” New authoritative accounting guidance under ASC Topic 805, “Business Combinations” amended prior guidance on the subsequent accounting for an indemnification asset recognized at the acquisition date as a result of a government-assisted (Federal Deposit Insurance Corporation) acquisition of a financial institution that includes a loss-sharing agreement. The new authoritative guidance requires that at each subsequent reporting date, an acquirer measure an indemnification asset on the same basis as the indemnified liability or asset, subject to any contractual limitations on its amount, and, for an indemnification asset that is not subsequently measured at fair value, management's assessment of the collectability of the indemnification asset. Any amortization of changes in value should be limited to the contractual term of the indemnification agreement (that is, the lesser of the term of the indemnification agreement and the remaining life of the indemnified assets). The Company adopted this new authoritative guidance on January 1, 2013, and it did not have an impact on the Company's statements of operations and financial condition.
ASC Topic 210 “Disclosures about Offsetting Assets and Liabilities.” New authoritative accounting guidance under ASC Topic 210, “Disclosures about Offsetting Assets and Liabilities” amended prior guidance to require an entity to disclose both gross and net information about both instruments and transactions eligible for offset in the statement of financial position and instruments and transactions subject to an agreement similar to a master netting arrangement. The instruments and transactions would include derivatives, sale and repurchase agreements and reverse sale and repurchase agreements, and securities borrowing and securities lending arrangements. This new authoritative guidance was further amended to clarify the scope of offsetting disclosures. The Company adopted the new authoritative guidance on January 1, 2013, and it did not have an impact on the Company's statements of operations and financial condition. See disclosures in Note 20.
ASC Topic 220 “Comprehensive Income.” New authoritative accounting guidance under ASC Topic 220, “Comprehensive Income” amended prior guidance to improve the reporting of reclassifications out of accumulated other comprehensive income by requiring an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present, either on the face of the statement or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income if the amount reclassified is required under U.S. GAAP. The Company adopted this new authoritative guidance on January 1, 2013, and it did not have an impact on the Company's statements of operations and financial condition.
ASC Topic 815 “Derivatives and Hedging.” New authoritative accounting guidance under ASC Topic 815, “Derivatives and Hedging” amended prior guidance to permit the Fed Funds Effective Swap Rate (OIS) to be used as a U.S. benchmark interest rate for hedge accounting purposes, in addition to U.S. government treasury obligation rates and London Interbank Offered Rate swap rate. The amendments also remove the restriction on using different benchmark rates for similar hedges. The new authoritative guidance was effective prospectively for new and redesignated hedging relationships entered into on or after July 17, 2013 and it did not have an impact on the Company's statements of operations and financial condition.
ASC Topic 740 “Income Taxes.” New authoritative accounting guidance under ASC Topic 740, “Income Taxes” amended prior guidance to include explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. An unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The new authoritative guidance will be for reporting periods after January 1, 2014 and is not expected to have an impact on the Company's statements of operations and financial condition.
ASC Topic 310 "Receivables." New authoritative accounting guidance under ASC Topic 310, “Receivables” amended prior guidance to clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical
possession of residential real estate property collateralizing a consumer mortgage loan, upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additionally, the amendments require interim and annual disclosures. The new authoritative guidance will be for reporting periods after January 1, 2015 and is not expected to have an impact on the Company's statements of operations and financial condition.
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.

Business_Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Business Combinations	'
	Business Combinations
	Celtic Leasing Corp.  The following 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, assets and liabilities acquired are recorded at their estimated fair values, net of applicable income tax effects.  The excess cost over fair value of net assets acquired is recorded as goodwill.  In the event that the fair value of net assets acquired exceeds the cost, the Company will record a gain on the acquisition.
	On December 28, 2012, MB Financial Bank acquired a 100% equity interest in Celtic Leasing Corp. (“Celtic”), a privately held, mid-ticket equipment leasing company. Celtic specializes in solutions for the health care, legal, technology, and manufacturing industries. MB Financial Bank estimated contingent consideration related to the transaction which may be paid out at future dates. This consideration is based on the performance of lease residual values which will be determined in future years over an earn-out period. As the consideration paid for Celtic exceeded the net assets acquired, goodwill was recorded on the acquisition. Goodwill recorded in the transaction is not tax deductible. The purchase accounting entries were finalized for lease loans, goodwill and other intangibles in the fourth quarter of 2013. The impact of any future changes to the amount of contingent consideration will be reflected in the statement of operations.
	Estimated fair values of the assets acquired and liabilities assumed in the Celtic transaction, as of the closing date of the transaction were as follows (in thousands):
	Assets Acquired and Liabilities Assumed
	(Dollar Amounts in Thousands)
		Celtic
		December 28,
		2012
	ASSETS
	Cash and cash equivalents	$	31,647
	Investment securities available for sale	635
	Loans and leases	32,933
	Premises and equipment	81
	Goodwill	36,300
	Other intangibles	5,028
	Other assets	27,323
	Total assets	$	133,947
	LIABILITIES
	Accrued expenses and other liabilities	$	75,290
	Total liabilities	$	75,290
	Cash paid (received) on acquisition	$	58,657
	Net gain recorded on acquisition	$	—
	Taylor Capital Group, Inc. On July 14, 2013, the Company and Taylor Capital Group, Inc. (“Taylor Capital”) entered into an Agreement and Plan of Merger (the "Merger Agreement") whereby the Company will acquire Taylor Capital. The Merger Agreement provides that, upon the terms and subject to the conditions set forth therein, Taylor Capital will merge with and into the Company, with the Company as the surviving corporation in the merger. Immediately following the Merger, Taylor Capital's wholly owned bank subsidiary, Cole Taylor Bank, will merge with the Company's wholly owned bank subsidiary, MB Financial Bank. Cole Taylor Bank is a commercial bank headquartered in Chicago with $5.7 billion in assets, $3.6 billion in loans and $3.7 billion in deposits as of December 31, 2013.
	Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the "Effective Time"), each share of Taylor Capital common stock and each share of Taylor Capital nonvoting convertible preferred stock ("non-voting preferred stock") will be converted into the right to receive, promptly following the Effective Time, (1) 0.64318 of a share of the Company's common stock and (2) $4.08 in cash. All "in-the-money" Taylor Capital stock options and warrants outstanding immediately prior to the Effective Time will be canceled in exchange for a cash payment as provided in the Merger Agreement, as will all then-outstanding unvested restricted stock awards of Taylor Capital; however, the cash consideration paid for such restricted stock awards will remain subject to vesting or other lapse restrictions. Each share of Taylor Capital's Perpetual Non-Cumulative Preferred Stock, Series A, will be exchanged for a share of a series of preferred stock of the Company with substantially identical terms.
	The merger is subject to regulatory approvals, approval by the Company's stockholders, approval by Taylor Capital stockholders and certain other customary closing conditions and is expected to close in the first half of 2014. In addition, it is a condition to the Company's obligation to complete the Merger that the shares of Taylor Capital common stock and Taylor Capital nonvoting preferred stock whose holders have perfected appraisal rights under Delaware law represent less than nine percent of the total number of outstanding shares of Taylor Capital common stock and Taylor Capital nonvoting preferred stock.

Restrictions_on_Cash_and_Due_F

Restrictions on Cash and Due From Banks	12 Months Ended
	Dec. 31, 2013
Restrictions on Cash and Due from Banks [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 $75.1 million and $64.4 million at December 31, 2013 and 2012, 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, 2013
Investments Securities [Abstract]	'
Investment Securities	'
	Investment Securities
	Carrying amounts and fair values of investment securities were as follows (in thousands):
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	December 31, 2013
	Available for Sale
	U.S. Government sponsored agencies and enterprises	$	50,486		$	1,704		$	(122	)	$	52,068
	States and political subdivisions	19,398			22			(277		)	19,143
	Residential mortgage-backed securities	696,415			8,555			(3,737		)	701,233
	Commercial mortgage-backed securities	50,891			2,050			—			52,941
	Corporate bonds	284,083			1,597			(2,610		)	283,070
	Equity securities	10,649			—			(192		)	10,457
		1,111,922			13,928			(6,938		)	1,118,912
	Held to Maturity
	States and political subdivisions	932,955			7,584			(4,366		)	936,173
	Residential mortgage-backed securities	249,578			13,178			—			262,756
		1,182,533			20,762			(4,366		)	1,198,929
	Total	$	2,294,455		$	34,690		$	(11,304	)	$	2,317,841
	December 31, 2012
	Available for Sale
	U.S. Government sponsored agencies and enterprises	$	38,605		$	2,710		$	—		$	41,315
	States and political subdivisions	679,991			45,571			(543		)	725,019
	Residential mortgage-backed securities	930,413			14,038			(5,249		)	939,202
	Commercial mortgage-backed securities	51,100			3,026			—			54,126
	Corporate bonds	97,014			213			(553		)	96,674
	Equity securities	11,398			447			(10		)	11,835
		1,808,521			66,005			(6,355		)	1,868,171
	Held to Maturity
	States and political subdivisions	237,563			21,039			—			258,602
	Residential mortgage-backed securities	255,858			21,221			—			277,079
		493,421			42,260			—			535,681
	Total	$	2,301,942		$	108,265		$	(6,355	)	$	2,403,852
	Securities of states and political subdivisions with a fair value of $656.6 million were transferred from available for sale to held to maturity during the third quarter of 2013, which is the new cost basis. As of the date of the transfer, the resulting unrealized holding gain continues to be reported as a separate component of stockholders’ equity as accumulated other comprehensive income, net of tax. This unrealized gain will be amortized over the remaining life of the securities as a yield adjustment.
	We do not have any meaningful direct or indirect holdings of subprime residential mortgage loans, home equity lines of credit, or any Fannie Mae or Freddie Mac preferred or common equity securities in our investment portfolio.
	The Company has no direct exposure to the State of Illinois, but approximately 27% of the state and political subdivisions portfolio consists of securities issued by municipalities located in Illinois as of December 31, 2013. Approximately 90% of such securities were general obligation issues as of December 31, 2013.
	Unrealized losses on investment securities and the fair value of the related securities at December 31, 2013 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	$	18,598		$	(122	)	$	—		$	—		$	18,598	$	(122	)
	States and political subdivisions	2,275			(166		)	4,748			(111		)	7,023		(277		)
	Residential mortgage-backed securities	232,807			(2,905		)	44,182			(832		)	276,989		(3,737		)
	Corporate bonds	122,344			(2,606		)	705			(4		)	123,049		(2,610		)
	Equity securities	10,457			(192		)	—			—			10,457		(192		)
		386,481			(5,991		)	49,635			(947		)	436,116		(6,938		)
	Held to Maturity
	States and political subdivisions	235,016			(4,330		)	1,301			(36		)	236,317		(4,366		)
	Totals	$	621,497		$	(10,321	)	$	50,936		$	(983	)	$	672,433	$	(11,304	)
	Unrealized losses on investment securities and the fair value of the related securities at December 31, 2012 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
	States and political subdivisions	$	57,540		$	(543	)	$	—		$	—		$	57,540	$	(543	)
	Residential mortgage-backed securities	270,539			(5,083		)	16,434			(166		)	286,973		(5,249		)
	Corporate bonds	58,241			(553		)	—			—			58,241		(553		)
	Equity securities	30			(10		)	—			—			30		(10		)
	Totals	$	386,350		$	(6,189	)	$	16,434		$	(166	)	$	402,784	$	(6,355	)
	The total number of security positions in the investment portfolio in an unrealized loss position at December 31, 2013 was 345 compared to 117 at December 31, 2012. 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 or not the Company is more likely than not to sell the security before recovery of its cost basis.
	As of December 31, 2013, management does not have the intent to sell any of the securities in the table above and believes that it is 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 bonds approach their maturity date or repricing date or if market yields for such investments decline. Accordingly, as of December 31, 2013, management believes the impairments detailed in the table above are temporary.
	Net (losses) gains recognized on investment securities available for sale were as follows (in thousands):
	For the Years Ended December 31,
	2013			2012			2011
Realized gains	$	15		$	787		$	647
Realized losses	(2		)	(8		)	(7		)
Impairment charges	(14		)	(224		)	—
Net (losses) gains	$	(1	)	$	555		$	640
The amortized cost and fair value of investment securities as of December 31, 2013 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	$	504		$	505
Due after one year through five years	337,107			337,675
Due after five years through ten years	7,676			7,582
Due after ten years	8,680			8,519
Equity securities	10,649			10,457
Residential and commercial mortgage-backed securities	747,306			754,174
	1,111,922			1,118,912
Held to maturity:
Due in one year or less	27,708			27,715
Due after one year through five years	252,967			254,608
Due after five years through ten years	121,269			121,128
Due after ten years	531,011			532,722
Residential mortgage-backed securities	249,578			262,756
	1,182,533			1,198,929
Total	$	2,294,455		$	2,317,841
Investment securities available for sale with carrying amounts of $908.4 million and $989.6 million at December 31, 2013 and 2012, respectively, were pledged as collateral on public deposits and for other purposes as required or permitted by law. Of those pledged, the Company had investment securities available for sale pledged as collateral for advances from the Federal Home Loan Bank of $29.0 million and $32.1 million at December 31, 2013 and 2012, respectively.

Loans

Loans	12 Months Ended
	Dec. 31, 2013
Receivables [Abstract]	'
Loans	'
	Loans
	Loans consist of the following at (in thousands):
			December 31,
			2013				2012
	Commercial		$	1,281,377			$	1,220,472
	Commercial collateralized by assignment of lease payments		1,494,188				1,303,020
	Commercial real estate		1,647,700				1,761,832
	Residential real estate		314,440				314,359
	Construction real estate		141,253				110,261
	Indirect vehicle		262,632				208,633
	Home equity		268,289				305,186
	Other consumer		66,952				93,317
	Gross loans, excluding covered loans		5,476,831				5,317,080
	Covered loans		235,720				449,850
	Total loans(1)		$	5,712,551			$	5,766,930
	(1)          Gross loan balances at December 31, 2013 and 2012 are net of unearned income, including net deferred loan fees of $1.9 million and $1.1 million, respectively.
	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. Credit risk tends to be geographically concentrated in that a majority of the loan customers are located in the markets serviced by MB Financial Bank.
	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. These policies and procedures are reviewed and approved by the Board of Directors on a regular basis.
	Commercial Loans. Commercial credit is extended primarily 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 meaningful amount by the businesses' principal owners. Commercial loans are made based primarily on the historical and projected cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not behave 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.
	Commercial Loans Collateralized by Assignment of Lease Payments ("Lease Loans"). The Company makes lease loans to 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 or Standard & Poor's Rating Services. In the event the related lessee has not received any such rating, where the related lessee would be viewed under the underwriting polices of the Company as an investment grade company. Whether or not companies fall into this category, each lease loan is considered on its individual merit based on financial information available at the time of underwriting.
	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 cash flow loans and the repayment of these loans is largely dependent on the successful operation 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 controlled 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, they 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 primarily residential real estate, home equity lines and loans, credit cards, and indirect motorcycle loans using a matrix-based credit analysis as part of the underwriting process. Each loan type has a separate specified matrix which consists of several factors including debt to income, type of collateral and loan to collateral value, credit history and Company relationship with the borrower. Indirect loan and credit card underwriting involves the use of risk-based pricing in the underwriting process.
	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, 2013 and 2012, were approximately $24.0 million. Total advances on loans outstanding to executive officers and directors, including companies in which they have management control or controlling beneficial ownership, were $2.7 million, and total repayments were $2.7 million during the year ended December 31, 2013. In the opinion of management, these loans have similar terms to other customer loans and do not present more than normal risk of collection.
	A collateral pledge agreement exists whereby at all times, the Company must keep on hand, free of all other pledges, liens, and encumbrances, first mortgage loans and home equity loans with unpaid principal balances aggregating no less than 133% for first mortgage loans and 250% for home equity loans of the outstanding advances from the Federal Home Loan Bank.  As of December 31, 2013 and 2012, the Company had $518.4 million and $28.4 million, respectively, of loans pledged as collateral for Federal Home Loan Bank advances.
	The following table presents the contractual aging of the recorded investment in past due loans by class of loans as of December 31, 2013 and 2012 (in thousands):
			Current				30-59 Days				60-89 Days				Loans Past Due			Total				Total
							Past Due				Past Due				90 Days or More			Past Due
	31-Dec-13
	Commercial		$	1,273,302			$	5,952			$	626			$	1,497		$	8,075			$	1,281,377
	Commercial collateralized by assignment of lease payments		1,489,391				3,841				656				300			4,797				1,494,188
	Commercial real estate:
	Healthcare		213,665				—				—				3,064			3,064				216,729
	Industrial		372,975				5,465				—				1,404			6,869				379,844
	Multifamily		302,456				3,078				181				2,226			5,485				307,941
	Retail		334,198				328				2,816				7,258			10,402				344,600
	Office		155,936				—				—				2,066			2,066				158,002
	Other		233,464				4,898				259				1,963			7,120				240,584
	Residential real estate		302,362				1,422				1,030				9,626			12,078				314,440
	Construction real estate		138,563				391				—				2,299			2,690				141,253
	Indirect vehicle		259,488				2,210				657				277			3,144				262,632
	Home equity		257,219				1,725				2,165				7,180			11,070				268,289
	Other consumer		66,866				81				1				4			86				66,952
	Gross loans, excluding covered loans		5,399,885				29,391				8,391				39,164			76,946				5,476,831
	Covered loans		135,717				902				3,346				95,755			100,003				235,720
	Total loans (1)		$	5,535,602			$	30,293			$	11,737			$	134,919		$	176,949			$	5,712,551
	Nonperforming loan aging		$	56,339			$	14,325			$	3,283			$	32,614		$	50,222			$	106,561
	Non-covered loans related to FDIC transactions (2)		$	13,541			$	163			$	391			$	6,550		$	7,104			$	20,645
	December 31, 2012
	Commercial		$	1,215,957			$	639			$	754			$	3,122		$	4,515			$	1,220,472
	Commercial collateralized by assignment of lease payments		1,288,341				11,252				2,847				580			14,679				1,303,020
	Commercial real estate:
	Healthcare		192,039				—				—				3,238			3,238				195,277
	Industrial		402,813				548				424				7,700			8,672				411,485
	Multifamily		353,966				1,282				—				3,103			4,385				358,351
	Retail		375,900				6,933				518				9,331			16,782				392,682
	Office		186,665				742				280				1,125			2,147				188,812
	Other		210,456				851				1,837				2,081			4,769				215,225
	Residential real estate		306,927				382				1,248				5,802			7,432				314,359
	Construction real estate		106,158				1,139				97				2,867			4,103				110,261
	Indirect vehicle		206,126				1,588				498				421			2,507				208,633
	Home equity		291,737				3,557				1,888				8,004			13,449				305,186
	Other consumer		93,266				47				—				4			51				93,317
Gross loans, excluding covered loans		5,230,351				28,960				10,391				47,378			86,729				5,317,080
Covered loans		301,260				5,831				7,478				135,281			148,590				449,850
Total loans (1)		$	5,531,611			$	34,791			$	17,869			$	182,659		$	235,319			$	5,766,930
Nonperforming loan aging		$	69,836			$	3,171			$	3,718			$	40,261		$	47,150			$	116,986
Non-covered loans related to FDIC transactions (2)		$	12,752			$	312			$	1,542			$	7,115		$	8,969			$	21,721
(1)          Includes loans related to the InBank FDIC-assisted transaction completed by MB Financial Bank in 2009.
(2)          Loans related to the InBank FDIC-assisted transaction completed by MB Financial Bank in 2009.
The following table presents the recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing by class of loans as of December 31, 2013 and 2012 (in thousands):
		2013								2012
						Loans past due								Loans past due
		Nonaccrual				90 days or more				Nonaccrual				90 days or more
						and still accruing								and still accruing
Commercial		$	17,781			$	—			$	23,886			$	229
Commercial collateralized by assignment of lease payments		4,276				291				1,180				222
Commercial real estate:
Healthcare		3,064				—				3,238				—
Industrial		15,265				155				19,179				147
Multifamily		5,145				—				7,225				—
Office		11,703				—				3,263				—
Retail		2,969				—				17,019				—
Other		19,991				—				9,437				—
Residential real estate		13,009				—				10,943				—
Construction real estate		475				—				1,028				—
Indirect vehicle		1,459				—				1,494				—
Home equity		10,969				—				17,486				1,000
Other consumer		9				—				9				1
Total		$	106,115			$	446			$	115,387			$	1,599
The reduction in interest income associated with loans on nonaccrual status was approximately $4.7 million, $5.6 million, and $11.9 million for the years ended December 31, 2013, 2012, and 2011, 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 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. Risk ratings are updated at least annually and any time the situation warrants.
Loans that are not rated are included in groups of homogeneous loans with similar risk and loss characteristics and therefore are not included in the tables below. The following tables present the risk category of loans by class of loans based on the most recent analysis performed and the contractual aging as of December 31, 2013 and 2012 (in thousands):
		Pass				Special				Substandard				Doubtful			Total
						Mention
31-Dec-13
Commercial		$	1,193,114			$	26,637			$	61,000			$	626		$	1,281,377
Commercial collateralized by assignment of lease payments		1,486,899				553				6,736				—			1,494,188
Commercial real estate:
Healthcare		189,705				21,186				2,774				3,064			216,729
Industrial		345,236				5,328				29,280				—			379,844
Multifamily		296,179				342				11,420				—			307,941
Retail		316,420				10,660				17,520				—			344,600
Office		151,393				2,682				3,927				—			158,002
Other		217,188				349				23,047				—			240,584
Construction real estate		139,847				540				866				—			141,253
Total		$	4,335,981			$	68,277			$	156,570			$	3,690		$	4,564,518
December 31, 2012
Commercial		$	1,136,294			$	33,068			$	50,895			$	215		$	1,220,472
Commercial collateralized by assignment of lease payments		1,292,241				3,322				7,457				—			1,303,020
Commercial real estate:
Healthcare		170,265				21,774				—				3,238			195,277
Industrial		355,218				15,243				41,024				—			411,485
Multifamily		318,991				25,297				14,063				—			358,351
Retail		340,919				25,096				26,667				—			392,682
Office		159,056				7,120				22,636				—			188,812
Other		193,824				2,553				18,848				—			215,225
Construction real estate		97,724				552				11,985				—			110,261
Total		$	4,064,532			$	134,025			$	193,575			$	3,453		$	4,395,585
Approximately $80.7 million and $85.5 million of the substandard and doubtful loans were non-performing as of December 31, 2013 and 2012, 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 as of December 31, 2013 and 2012 (in thousands):
		Performing				Non-performing				Total
31-Dec-13
Residential real estate		$	301,431			$	13,009			$	314,440
Indirect vehicle		261,173				1,459				262,632
Home equity		257,320				10,969				268,289
Other consumer		66,943				9				66,952
Total		$	886,867			$	25,446			$	912,313
December 31, 2012
Residential real estate		$	303,416			$	10,943			$	314,359
Indirect vehicle		207,139				1,494				208,633
Home equity		286,700				18,486				305,186
Other consumer		93,307				10				93,317
Total		$	890,562			$	30,933			$	921,495
The following tables present loans individually evaluated for impairment by class of loans as of December 31, 2013 and 2012 (in thousands):
		31-Dec-13
		Unpaid				Recorded				Partial				Allowance for			Average				Interest
		Principal				Investment				Charge-offs				Loan Losses			Recorded				Income
		Balance												Allocated			Investment				Recognized
With no related allowance recorded:
Commercial		$	8,903			$	8,903			$	—			$	—		$	8,259			$	—
Commercial collateralized by assignment of lease payments		3,401				3,401				—				—			1,030				6
Commercial real estate:
Healthcare		—				—				—				—			2,698				—
Industrial		7,560				7,560				—				—			8,900				—
Multifamily		1,166				1,166				—				—			758				11
Retail		4,466				4,466				—				—			3,628				—
Office		559				527				32				—			922				—
Other		2,963				2,963				—				—			4,380				—
Residential real estate		4,234				4,234				—				—			3,260				—
Construction real estate		—				—				—				—			—				—
Indirect vehicle		—				—				—				—			—				—
Home equity		577				577				—				—			797				—
Other consumer		—				—				—				—			—				—
With an allowance recorded:
Commercial		8,923				8,919				4				4,284			13,476				4
Commercial collateralized by assignment of lease payments		1,060				1,060				—				144			1,279				192
Commercial real estate:
Healthcare		3,186				3,064				122				382			8,189				—
Industrial		7,707				7,705				2				3,038			3,699				—
Multifamily		5,374				5,374				—				1,661			6,443				340
Retail		14,169				12,428				1,741				1,511			12,885				280
Office		2,442				2,442				—				791			4,045				—
Other		20,367				17,029				3,338				796			12,868				20
Residential real estate		13,496				12,710				786				3,119			12,966				245
Construction real estate		475				475				—				227			1,603				—
Indirect vehicle		173				123				50				57			86				—
Home equity		23,840				23,395				445				1,358			24,283				772
Other consumer		—				—				—				—			—				—
Total		$	135,041			$	128,521			$	6,520			$	17,368		$	136,454			$	1,870
		December 31, 2012
		Unpaid				Recorded				Partial				Allowance for			Average				Interest
		Principal				Investment				Charge-offs				Loan Losses			Recorded				Income
		Balance												Allocated			Investment				Recognized
With no related allowance recorded:
Commercial		$	10,993			$	9,505			$	1,488			$	—		$	14,089			$	105
Commercial collateralized by assignment of lease payments		390				390				—				—			278				9
Commercial real estate:
Healthcare		10,943				3,238				7,705				—			2,751				—
Industrial		16,891				14,940				1,951				—			16,374				29
Multifamily		800				800				—				—			1,340				14
Retail		5,372				4,917				455				—			9,241				—
Office		1,568				1,568				—				—			1,151				—
Other		4,860				4,860				—				—			6,005				—
Residential real estate		3,097				2,711				386				—			6,476				—
Construction real estate		—				—				—				—			577				—
Indirect vehicle		—				—				—				—			—				—
Home equity		2,558				2,558				—				—			8,976				—
Other consumer		—				—				—				—			182				—
With an allowance recorded:
Commercial		14,484				14,381				103				3,620			8,455				—
Commercial collateralized by assignment of lease payments		885				885				—				188			1,130				95
Commercial real estate:
Healthcare		—				—				—				—			3,901				—
Industrial		5,525				4,238				1,287				1,255			2,443				—
Multifamily		8,233				7,249				984				2,284			5,847				180
Retail		23,144				17,257				5,887				3,604			10,058				293
Office		1,706				1,695				11				522			1,904				—
Other		4,661				4,577				84				1,263			6,082				16
Residential real estate		10,565				10,565				—				2,858			3,417				227
Construction real estate		4,552				2,167				2,385				497			3,775				61
Indirect vehicle		—				—				—				—			—				—
Home equity		13,765				13,763				2				850			4,800				563
Other consumer		—				—				—				—			—				—
Total		$	144,992			$	122,264			$	22,728			$	16,941		$	119,252			$	1,592
Average impaired loans for the years ended December 31, 2013, 2012 and 2011 were $136.5 million, $119.3 million and $267.8 million, respectively.  Interest income recognized on impaired loans was $1.9 million, $1.6 million and $3.0 million for the years ended December 31, 2013, 2012 and 2011, respectively.
Impaired loans included accruing restructured loans of $29.4 million and $21.3 million that have been modified and are performing in accordance with those modified terms as of December 31, 2013 and 2012, respectively.  In addition, impaired loans included $25.0 million and $28.4 million of non-performing, restructured loans as of December 31, 2013 and 2012, 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, deferral of past due interest or principal, implementing an A/B note structure, redeeming past due taxes, reduction of interest rates, extending maturities and modification of 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. Programs that we offer to residential real estate borrowers include the Home Affordable Refinance Program (“HARP”) and a restructuring program similar to the Home Affordable Modification Program (“HAMP”) for first mortgage borrowers as well as the Second Lien Modification Program (“2MP”) and similar programs for home equity borrowers in keeping with the restructuring techniques discussed above.
Occasionally, the Company will restructure a note into two separate notes (A/B structure), charging off the entire B portion of the note. The A note is structured with appropriate loan-to-value and cash flow coverage ratios that provide for a high likelihood of repayment. The A note is classified as a non-performing note until the borrower has displayed a historical payment performance for a reasonable time prior to and subsequent to the restructuring. A period of sustained repayment for at least six months generally is required to return the note to accrual status provided that management has determined that the performance is reasonably expected to continue. The A note will be classified as a restructured note (either performing or nonperforming) through the calendar year of the restructuring that the historical payment performance has been established. As of December 31, 2013, there was approximately $1.1 million in recorded investment in relation to one A/B structure.  As of December 31, 2012, there was approximately $3.1 million in recorded investment in relation to one A/B structures.  Both of these A/B structures are included above as accruing restructured loans.
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 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 would not be able to meet the modified terms of the loan, the loan would 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 loss process. See Note 1 for additional information. 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 have been restructured during the year ended December 31, 2013 (dollars in thousands):
		31-Dec-13
		Number of		Pre-Modification Recorded				Post-Modification Recorded				Charge-offs and
		Loans		Investment				Investment				Specific Reserves
Performing:
Commercial real estate:
Multifamily		1		$	601			$	601			$	—
Residential real estate		6		910				910				—
Home equity		14		2,204				2,204				—
Total		21		$	3,715			$	3,715			$	—
Non-Performing:
Commercial		2		$	1,251			$	1,251			$	673
Commercial collateralized by assignment of lease payments		1		3,401				3,401				—
Commercial real estate:
Healthcare		1		3,164				3,164				496
Industrial		4		2,570				2,570				1,425
Multifamily		2		623				623				169
Retail		3		862				862				235
Other		1		84				84				23
Residential real estate		9		1,803				1,682				121
Indirect vehicle		26		171				129				42
Home equity		26		3,430				3,430				—
Total		75		$	17,359			$	17,196			$	3,184
The following table presents loans that have been restructured during the year ended December 31, 2012 (dollars in thousands):
		December 31, 2012
		Number of			Pre-Modification Recorded				Post-Modification Recorded				Charge-offs and
		Loans			Investment				Investment				Specific Reserves
Performing:
Commercial real estate:
Multifamily		2			$	262			$	262			$	—
Retail		1			236				236				—
Residential real estate		4			1,575				1,575				—
Construction real estate		1			1,158				1,158				—
Home equity		53			7,943				7,867				76
Total		61			$	11,174			$	11,098			$	76
Non-Performing:
Commercial		4			$	3,305			$	3,305			$	73
Commercial collateralized by assignment of lease payments		1			202				202				168
Commercial real estate:
Industrial		1			284				284				77
Multifamily		2			333				333				220
Retail		4			818				818				204
Other		1			157				157				50
Residential real estate		5			1,092				857				235
Home equity		42			5,283				5,283				—
Total		60			$	11,474			$	11,239			$	1,027
Of the troubled debt restructurings entered into during the past twelve months, $843 thousand subsequently defaulted during the year ended December 31, 2013.  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, 2013 (dollars in thousands):
		Performing				Non-performing
Beginning balance		$	21,256			$	28,418
Additions		3,715				17,359
Charge-offs		(71		)		(3,810		)
Principal payments, net		(2,813		)		(8,901		)
Removals		—				(565		)
Transfer to other real estate owned		—				(206		)
Transfer from non-performing/performing		8,603				1,260
Transfer to non-performing/performing		(1,260		)		(8,603		)
Ending balance		$	29,430			$	24,952
Approximately $8.6 million of non-performing troubled debt restructurings were transferred to performing status. A majority of these loans were identified as non-performing troubled debt restructurings during 2012 and have performed in accordance with the modified terms. The loans continue to be reported as performing troubled debt restructurings. The loans transferred to nonperforming in the table above were restructured in 2010 and 2011.
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, 2013 (dollars in thousands):
	December 31, 2013
	Extended				Extended				Extended				Extended
	Maturity,				Maturity, Delay				Maturity and				Maturity, Delay							Delay in
	Amortization				in Payments and				Delay in Payments				in Payments and							Payments or
	and Reduction				Reduction of				or Reduction of				Reduction of			Extended				Reduction of
	of Interest Rate				Interest Rate				Interest Rate				Amount			Maturity				Interest Rate			Total
Commercial	$	42			$	—			$	1,209			$	—		$	—			$	—		$	1,251
Commercial collateralized by assignment of lease payments	—				—				3,401				—			—				—			3,401
Commercial real estate:
Healthcare	—				—				—				3,164			—				—			3,164
Industrial	—				—				—				—			2,570				—			2,570
Multifamily	187				—				—				—			601				436			1,224
Retail	256				205				401				—			—				—			862
Office	—				—				—				—			—				—			—
Other	84				—				—				—			—				—			84
Residential real estate	1,917				—				—				—			178				618			2,713
Construction real estate	—				—				—				—			—				—			—
Indirect vehicle	—				—				—				—			44				127			171
Home equity	2,875				—				708				—			440				1,611			5,634
Other consumer	—				—				—				—			—				—			—
Total	$	5,361			$	205			$	5,719			$	3,164		$	3,833			$	2,792		$	21,074
Activity in the allowance for loan losses was as follows (in thousands):
		Year Ended December 31,
		2013				2012				2011
Balance at beginning of year		$	128,279			$	135,975			$	192,217
Provision for credit losses		(5,804		)		(8,900		)		120,750
Charge-offs:
Commercial		3,706				2,408				17,571
Commercial collateralized by assignment of lease payments		—				1,721				1,466
Commercial real estate		7,517				11,377				96,633
Residential real estate		2,796				2,944				12,643
Construction real estate		980				4,007				52,917
Indirect vehicle		2,911				2,259				2,836
Home equity		3,692				4,551				11,066
Other consumer		2,073				1,349				1,648
Total charge-offs		23,675				30,616				196,780
Recoveries:
Commercial		3,156				3,475				5,370
Commercial collateralized by assignment of lease payments		1,131				6,720				225
Commercial real estate		6,025				16,987				3,332
Residential real estate		479				501				49
Construction real estate		1,616				2,019				8,590
Indirect vehicle		1,411				1,096				1,399
Home equity		594				671				224
Other consumer		250				351				599
Total recoveries		14,662				31,820				19,788
Net charge-offs (recoveries)		9,013				(1,204		)		176,992
Allowance for credit losses		113,462				128,279				135,975
Allowance for unfunded credit commitments		(1,716		)		(4,075		)		(9,177		)
Balance at December 31,		$	111,746			$	124,204			$	126,798
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, 2013 and 2012 (in thousands):
		Commercial				Commercial				Commercial				Residential			Construction				Indirect			Home		Other Consumer		Unfunded			Total
						collateralized  by				real estate				real estate			real estate				vehicle			equity				Commitments
						assignment of
						lease payments
December 31, 2013
Allowance for credit losses:
Beginning balance		$	24,943			$	7,755			$	61,056			$	6,941		$	11,222			$	1,324		$	9,401	$	1,562	$	4,075		$	128,279
Transfer to (from) allowance for unfunded credit commitments		—				—				—				—			500				—			—		—		(500		)	—
Charge-offs		3,706				—				7,517				2,796			980				2,911			3,692		2,073		—			23,675
Recoveries		3,156				1,131				6,025				479			1,616				1,411			594		250		—			14,662
Provision		(932		)		273				(7,936		)		4,248			(5,502		)		1,838			2,175		1,891		(1,859		)	(5,804		)
Ending balance		$	23,461			$	9,159			$	51,628			$	8,872		$	6,856			$	1,662		$	8,478	$	1,630	$	1,716		$	113,462
Ending allowance balance attributable to loans:
Individually evaluated for impairment		$	4,284			$	144			$	8,179			$	3,119		$	227			$	57		$	1,358	$	—	$	689		$	18,057
Collectively evaluated for impairment		18,693				9,015				41,763				5,753			6,567				1,605			7,120		1,630		1,027			93,173
Acquired and accounted for under ASC 310-30 (1)		484				—				1,686				—			62				—			—		—		—			2,232
Total ending allowance balance		$	23,461			$	9,159			$	51,628			$	8,872		$	6,856			$	1,662		$	8,478	$	1,630	$	1,716		$	113,462
Loans:
Individually evaluated for impairment		$	17,822			$	4,461			$	64,724			$	16,944		$	475			$	123		$	23,972	$	—	$	—		$	128,521
Collectively evaluated for impairment		1,246,523				1,489,727				1,582,976				293,883			140,778				262,509			244,317		66,952		—			5,327,665
Acquired and accounted for under ASC 310-30 (1)		35,673				—				140,504				5,448			48,313				—			107		26,320		—			256,365
Total ending loans balance		$	1,300,018			$	1,494,188			$	1,788,204			$	316,275		$	189,566			$	262,632		$	268,396	$	93,272	$	—		$	5,712,551
December 31, 2012
Allowance for credit losses:
Beginning balance		$	21,106			$	7,561			$	68,695			$	3,935		$	15,639			$	1,834		$	7,333	$	695	$	9,177		$	135,975
Transfer to (from) allowance for unfunded credit commitments		—				—				—				—			1,132				—			—		—		(1,132		)	—
Charge-offs		2,408				1,721				11,377				2,944			4,007				2,259			4,551		1,349		—			30,616
Recoveries		3,475				6,720				16,987				501			2,019				1,096			671		351		—			31,820
Provision		2,770				(4,805		)		(13,249		)		5,449			(3,561		)		653			5,948		1,865		(3,970		)	(8,900		)
Ending balance		$	24,943			$	7,755			$	61,056			$	6,941		$	11,222			$	1,324		$	9,401	$	1,562	$	4,075		$	128,279
Ending allowance balance attributable to loans:
Individually evaluated for impairment		$	3,620			$	188			$	8,928			$	2,858		$	497			$	—		$	850	$	—	$	3,499		$	20,440
Collectively evaluated for impairment		18,878				7,567				50,120				4,083			10,662				1,324			8,551		1,562		576			103,323
Acquired and accounted for under ASC 310-30 (1)		2,445				—				2,008				—			63				—			—		—		—			4,516
Total ending allowance balance		$	24,943			$	7,755			$	61,056			$	6,941		$	11,222			$	1,324		$	9,401	$	1,562	$	4,075		$	128,279
Loans:
Individually evaluated for impairment		$	23,886			$	1,275			$	65,339			$	13,276		$	2,167			$	—		$	16,321	$	—	$	—		$	122,264
Collectively evaluated for impairment		1,178,804				1,301,745				1,696,493				297,144			108,094				208,633			288,865		93,317		—			5,173,095
Acquired and accounted for under ASC 310-30 (1)		65,658				—				247,390				6,528			118,360				—			465		33,170		—			471,571
Total ending loans balance		$	1,268,348			$	1,303,020			$	2,009,222			$	316,948		$	228,621			$	208,633		$	305,651	$	126,487	$	—		$	5,766,930
(1)  Loans acquired in FDIC-assisted transactions and accounted for under ASC Subtopic 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 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 310-20 "Nonrefundable Fees and Other Costs" as these loans do not have evidence of credit deterioration since origination.
•	Non-impaired loans (typically past-due loans, special mention loans and performing substandard loans) are accounted for in accordance with ASC 310-30 as 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 310-30 as they display significant credit deterioration since origination.
In accordance with ASC 310-30, for both purchased non-impaired loans and purchased impaired loans, 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 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.
During the year ended December 31, 2013, there was a negative provision for credit losses of $2.5 million and net recoveries of $218 thousand, respectively, in relation to 15 pools of purchased loans with a total carrying amount of $195.5 million as of December 31, 2013. During the year ended December 31, 2012, there was a provision for credit losses of $8.1 million and net charge-offs of $4.4 million in relation to 14 pools of purchased loans with a total carrying amount of $261.9 million as of December 31, 2012.  There was $2.2 million in allowance for loan losses related to these purchased loans at December 31, 2013 and $4.5 million at December 31, 2012.  The provision for credit losses and accompanying charge-offs are included in the table above.
Changes in the accretable yield for loans acquired in FDIC-assisted transactions and accounted for under ASC 310-30 were as follows for the years ended December 31, 2013 and 2012 (in thousands):
		Year Ended December 31,
		2013				2012
Balance at beginning of period		$	5,685			$	18,703
Accretion		(4,456		)		(13,535		)
Other		1,108				517
Balance at end of period		$	2,337			$	5,685
In our FDIC-assisted transactions, the fair value of purchased 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, MB Financial Bank 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.
When cash flow estimates are adjusted downward for a particular loan pool, the FDIC indemnification asset is increased. An allowance for loan losses is established for the impairment of the loans. A provision for loan losses is recognized for the difference between the increase in the FDIC indemnification asset and the decrease in cash flows.
When cash flow estimates are adjusted upward for a particular loan pool, the FDIC indemnification asset is decreased. The difference between the decrease in the FDIC indemnification asset and the increase in cash flows is accreted over the estimated life of the loan pool.
When cash flow estimates are adjusted downward for covered foreclosed real estate, the FDIC indemnification asset is increased. A charge is recognized for the difference between the increase in the FDIC indemnification asset and the decrease in cash flows.
When cash flow estimates are adjusted upward for covered foreclosed real estate, the FDIC indemnification asset is decreased. Any write-down after the transfer to covered foreclosed real estate is reversed.
In both scenarios, the clawback liability (the amount the FDIC requires MB Financial Bank to pay back if certain thresholds are met) will increase or decrease accordingly.
The carrying amount of covered loans and other purchased non-covered loans at December 31, 2013 consisted of purchased credit-impaired loans and non-credit-impaired loans as shown in the following table (in thousands):
31-Dec-13		Purchased				Purchased  Non-Impaired				Total
		Impaired				Loans
		Loans
Covered loans:
Commercial related (1)		$	9,445			$	5,629			$	15,074
Commercial		803				2,764				3,567
Commercial real estate		51,762				88,742				140,504
Construction real estate		41,928				6,385				48,313
Other		2,529				25,733				28,262
Total covered loans		$	106,467			$	129,253			$	235,720
Estimated receivable amount from the FDIC under the loss-share agreement (2)		$	570			$	9,974			$	10,544
Non covered loans:
Commercial related (3)		$	4,726			$	12,306			$	17,032
Other		89				3,524				3,613
Total non-covered loans		$	4,815			$	15,830			$	20,645
-1	Covered commercial related loans include commercial, commercial real estate and construction real estate loans acquired in connection with the Heritage and Benchmark FDIC-assisted transactions.
-2	Estimated reimbursable amounts from the FDIC under the loss-share agreement exclude $1.1 million in reimbursable amounts related to covered other real estate owned.
-3	Non covered commercial related loans include commercial, commercial real estate and construction real estate for InBank.
Outstanding balances on purchased loans from the FDIC were $248.6 million and $515.7 million as of December 31, 2013 and 2012, respectively.  The related carrying amount on loans purchased from the FDIC was $235.7 million and $471.6 million as of December 31, 2013 and 2012, respectively.

Lease_Investments

Lease Investments	12 Months Ended
	Dec. 31, 2013
Lease Investments	'
Lease Investments	'
	Lease Investments
	The lease portfolio is comprised of various types of equipment, generally technology related, including computer systems and satellite equipment, medical equipment, material handling and general manufacturing equipment.
	Lease investments by categories follow (in thousands):
		December 31,
		2013			2012
	Direct finance leases:
	Minimum lease payments	$	155,945		$	96,834
	Estimated unguaranteed residual values	31,272			32,013
	Less: unearned income	(14,473		)	(6,995		)
	Direct finance leases (1)	$	172,744		$	121,852
	Leveraged leases:
	Minimum lease payments	$	24,320		$	28,831
	Estimated unguaranteed residual values	2,508			2,714
	Less: unearned income	(1,644		)	(2,376		)
	Less: related non-recourse debt	(23,243		)	(27,319		)
	Leveraged leases (1)	$	1,941		$	1,850
	Operating leases:
	Equipment, at cost	$	218,473		$	222,083
	Less accumulated depreciation	(87,384		)	(92,260		)
	Lease investments, net	$	131,089		$	129,823
	(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 leverage 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 $17.5 million at December 31, 2013 and $21.1 million at December 31, 2012.
	The minimum lease payments receivable for the various categories of leases are due as follows (in thousands) for the years ending December 31,
		Direct			Leveraged			Operating
		Finance
	Year	Leases			Leases			Leases			Total
	2014	$	62,310		$	13,622		$	34,839		$	110,771
	2015	45,899			7,395			23,263			76,557
	2016	26,814			2,482			13,981			43,277
	2017	13,247			642			5,232			19,121
	2018	5,838			179			2,011			8,028
	Thereafter	1,837			—			421			2,258
		$	155,945		$	24,320		$	79,747		$	260,012
	At December 31, 2013, 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			Leveraged			Operating
	December 31,	Leases			Leases			Leases			Total
	2014	$	12,417		$	802		$	13,239		$	26,458
	2015	7,427			974			8,310			16,711
	2016	6,203			609			9,793			16,605
	2017	2,975			105			6,680			9,760
	2018	1,420			18			3,533			4,971
	Thereafter	830			—			1,433			2,263
		$	31,272		$	2,508		$	42,988		$	76,768
	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 quarterly, and any write-downs or charge-offs deemed necessary are recorded in the period in which they become known. To mitigate this risk of loss, we usually limit individual leased equipment residuals to approximately $500 thousand per transaction and seek to diversify both the type of equipment leased and the industries in which the lessees participate.  Often times, there are several individual lease schedules under one master lease.  There were 3,590 leases at December 31, 2013 compared to 3,464 at December 31, 2012.  The average residual value per lease schedule was approximately $21 thousand at December 31, 2013 and $22 thousand at December 31, 2012.  The average residual value per master lease schedule was approximately $82 thousand at December 31, 2013 and $79 thousand at December 31, 2012.
	Income from lease financing, net was composed of (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Rental income	$	62,629		$	49,473		$	54,859
	Equipment maintenance contracts revenue, net of cost of sales	11,071			14,129			7,713
	Vendor promotional income	7,587			4,051			3,191
	Other lease related revenue	1,796			167			408
	Gain on sale of lease payments and leased equipment, net of residual write downs	12,002			4,708			3,158
	Income on lease investments, gross	95,085			72,528			69,329
	Less:
	Depreciation on operating leases	(33,842		)	(36,146		)	(42,390		)
	Lease financing, net	$	61,243		$	36,382		$	26,939
	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, 2013
Property, Plant and Equipment [Abstract]	'
Premises and Equipment	'
	Premises and Equipment
	Premises and equipment consisted of (in thousands):
		December 31,
		2013			2012
	Land and land improvements	$	67,389		$	69,832
	Buildings	98,675			97,365
	Furniture and equipment	97,766			88,425
	Buildings and leasehold improvements	55,639			49,813
		319,469			305,435
	Accumulated depreciation	(98,404		)	(83,902		)
	Premises and equipment, net	$	221,065		$	221,533
	Depreciation on premises and equipment totaled $18.1 million, $16.3 million, and $13.6 million for the years ended December 31, 2013, 2012, and 2011, respectively.

Goodwill_and_Intangibles

Goodwill and Intangibles	12 Months Ended
	Dec. 31, 2013
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. As of December 31, 2013, the Company had two reporting units: banking and leasing. Based on the Company's 2013 goodwill impairment testing, the fair values of the two reporting units were in excess of their carrying value. No impairment losses were recognized during the years ended December 31, 2013, 2012, or 2011. The carrying amount of goodwill was $423.4 million at December 31, 2013 and 2012.
	The Company has other intangible assets consisting of core deposit and client relationship intangibles that had a remaining weighted average amortization period of approximately four years as of December 31, 2013.
	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, 2013 and 2012 (in thousands):
			December 31,
			2013			2012
	Balance at beginning of period		$	29,512		$	29,494
	Amortization expense		(6,084		)	(5,010		)
	Other intangibles from business combinations		—			5,028
	Balance at end of period		$	23,428		$	29,512
	Gross carrying amount		$	60,292		$	61,429
	Accumulated amortization		(36,864		)	(31,917		)
	Net book value		$	23,428		$	29,512
	The following presents the estimated amortization expense of other intangible assets (in thousands):
	Years ending December 31,	Amount
	2014	$	4,748
	2015	4,030
	2016	3,418
	2017	3,071
	2018	2,812
	Thereafter	5,349
		$	23,428

Deposits

Deposits	12 Months Ended
	Dec. 31, 2013
Deposits [Abstract]	'
Deposits	'
	Deposits
	The composition of deposits was as follows (in thousands):
			December 31,
			2013		2012
	Demand deposit accounts, noninterest bearing		$	2,375,863	$	2,164,547
	NOW and money market accounts		2,682,419		2,747,273
	Savings accounts		855,394		811,333
	Certificates of deposit, $100,000 or more		827,413		1,020,033
	Other certificates of deposit		640,170		799,511
	Total		$	7,381,259	$	7,542,697
	Certificates of deposit of $100,000 or more included $224.2 million and $294.2 million of brokered deposits at December 31, 2013 and 2012, respectively.  Brokered deposits typically consist of smaller individual time certificates that have the same liquidity characteristics and yields consistent with time certificates of $100,000 or more.
	At December 31, 2013, the scheduled maturities of certificates of deposit were as follows (in thousands):
	2014	$	1,064,248
	2015	205,921
	2016	64,423
	2017	49,420
	2018	18,739
	Thereafter	64,832
		$	1,467,583

ShortTerm_Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2013
Short-term Debt [Abstract]	'
Short-Term Borrowings	'
	Short-Term Borrowings
	Short-term borrowings were as follows as of December 31, 2013 and 2012 (dollars in thousands):
		December 31,
		2013				2012
		Weighted				Weighted
		Average				Average
		Cost		Amount		Cost		Amount
	Customer repurchase agreements	0.2	%	$	193,389	0.23	%	$	208,242
	Federal Home Loan Bank advances	0.17	%	300,000		3.58	%	12,360
		0.18	%	$	493,389	0.42	%	$	220,602
	The Company had a fixed rate $300.0 million Federal Home Loan Bank ("FHLB") advance with a maturity date less than one year at December 31, 2013 and $12.4 million in fixed rate FHLB advances with a maturity date less than one year at December 31, 2012.  At December 31, 2013, the interest rate on the advance outstanding on that date was 0.17% and the advance matured on January 2, 2014. The Company has investment securities available for sale and loans pledged as collateral on these FHLB advances. See Note 4. Investment Securities and Note 5. Loans of the notes to the consolidated financial statements.
	Securities sold under agreements to repurchase 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.
	On March 9, 2012, the Company entered into a $35.0 million unsecured line of credit with a correspondent bank. Interest is payable at a rate of one month LIBOR + 2.00%. As of December 31, 2013, no amount was outstanding. The line originally matured on March 8, 2013, was renewed and is scheduled to mature on March 7, 2014.

Longterm_Borrowings

Long-term Borrowings	12 Months Ended
	Dec. 31, 2013
Long-term Debt, Unclassified [Abstract]	'
Long-term Borrowings	'
	Long-term Borrowings
	The Company had FHLB advances with original contractual maturities greater than one year of $4.3 million and $4.4 million at December 31, 2013 and 2012, respectively. As of December 31, 2013, the advances had fixed terms with effective interest rates, net of discounts, ranging from 3.23% to 5.87% and maturities ranging from April 2021 to April 2035. The Company has investment securities available for sale and loans pledged as collateral on these FHLB advances. See Note 4. Investment Securities and Note 5. Loans of the notes to the consolidated financial statements.
	The Company had notes payable to banks totaling $17.5 million and $21.1 million at December 31, 2013 and 2012, respectively, which as of December 31, 2013, were accruing interest at rates ranging from 2.50% to 12.00%.  Lease investments includes equipment with an amortized cost of $25.7 million and $29.7 million at December 31, 2013 and 2012, respectively, that is pledged as collateral on these notes.
	The Company had a $40.0 million 10-year structured repurchase agreement as of December 31, 2013 and 2012, which bears interest at a fixed rate borrowing of 4.75% and expires in 2016.
	During the first quarter of 2013, MB Financial Bank pre-paid a $50.0 million subordinated debt facility.  Interest was payable at a rate of 3-month LIBOR +1.70%.
	The principal payments on long-term borrowings are due as follows (in thousands):
		Amount
	Years ending December 31,
	2014	$	8,974
	2015	5,743
	2016	42,915
	2017	751
	2018	180
	Thereafter	3,596
		$	62,159

Junior_Subordinated_Notes_Issu

Junior Subordinated Notes Issued to Capital Trusts	12 Months Ended
	Dec. 31, 2013
JUNIOR SUBORDINATED NOTES ISSUED TO CAPITAL TRUSTS	'
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 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, 2013 (in thousands):
			Coal City		MB Financial		MB Financial		MB Financial
			Capital Trust I		Capital Trust II		Capital Trust III		Capital Trust IV
	Junior Subordinated Notes:
	Principal balance		$	25,774	$	36,083	$	10,310	$	20,619
	Annual interest rate		3-mo LIBOR + 1.80%		3-mo LIBOR + 1.40%		3-mo LIBOR + 1.50%		3-mo LIBOR + 1.52%
	Stated maturity date		September 1, 2028		September 15, 2035		September 23, 2036		September 15, 2036
	Call date		September 1, 2008		December 15, 2010		September 23, 2011		September 15, 2011
	Trust Preferred Securities:
	Face Value		$	25,000	$	35,000	$	10,000	$	20,000
	Annual distribution rate		3-mo LIBOR + 1.80%		3-mo LIBOR + 1.40%		3-mo LIBOR + 1.50%		3-mo LIBOR + 1.52%
	Issuance date		July 1998		August 2005		July 2006		August 2006
	Distribution dates (1)		Quarterly		Quarterly		Quarterly		Quarterly
			MB Financial		MB Financial		FOBB
			Capital Trust V		Capital Trust VI		Statutory Trust III (2)
	Junior Subordinated Notes:
	Principal balance		$	30,928	$	23,196	$	5,155
	Annual interest rate		3-mo LIBOR + 1.30%		3-mo LIBOR + 1.30%		3-mo LIBOR + 2.80%
	Stated maturity date		December 15, 2037		October 30, 2037		January 23, 2034
	Call date		December 15, 2012		October 30, 2012		January 23, 2009
	Trust Preferred Securities:
	Face Value		$	30,000	$	22,500	$	5,000
	Annual distribution rate		3-mo LIBOR + 1.30%		3-mo LIBOR + 1.30%		3-mo LIBOR + 2.80%
	Issuance date		September 2007		October 2007		December 2003
	Distribution dates (1)		Quarterly		Quarterly		Quarterly
	-1	All distributions are cumulative and paid in cash.
	-2	FOBB Statutory Trust III was established by First Oak Brook Bancshares, Inc. (“FOBB”) prior to the Company's acquisition of FOBB, and the junior subordinated note issued by FOBB to FOBB Statutory Trust III was assumed by the Company upon completion of the acquisition.
	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.

Lease_Commitments_and_Rental_E

Lease Commitments and Rental Expense	12 Months Ended
	Dec. 31, 2013
Lease Commitments and Rental Expense	'
Lease Commitments and Rental Expense	'
		Lease Commitments and Rental Expense
	The Company leases office space for certain branch offices.  At December 31, 2013, the future minimum annual rental commitments for these noncancelable leases and subleases of such space were as follows (in thousands):
			Gross		Sublease		Net
	Years ending December 31,		Rents		Rents		Rents
	2014		$	5,408	$	926	$	4,482
	2015		4,801		697		4,104
	2016		3,810		444		3,366
	2017		2,929		422		2,507
	2018		2,202		414		1,788
	Thereafter		16,580		1,005		15,575
			$	35,730	$	3,908	$	31,822
	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, 2013, 2012, and 2011 amounted to $4.7 million, $5.4 million, and $5.3 million, respectively.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2013
Employee Benefit Plans	'
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 2013, 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, 2013 was estimated to be $7.0 million and was $6.9 million and $6.1 million for the years ended December 31, 2012 and 2011, 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.  Discretionary Company contributions to these plans for the year ended December 31, 2013 were estimated to be approximately $643 thousand.  Contributions to these plans were $464 thousand and $492 thousand for the years ended December 31, 2012 and 2011, respectively.  In addition, pursuant to the Company’s agreement entered into with the Company’s 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, 2013, the fair value of the assets held in other publicly traded funds totaled $10.7 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 increase in fair market value of the assets and the obligation related to the deferred compensation plan was $1.6 million for the year ended December 31, 2013.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Taxes	'
Income Taxes	'
	Income Taxes
	The deferred taxes consist of (in thousands):
		December 31,
		2013			2012
	Deferred tax asset:
	Allowance for credit losses	$	44,418		$	50,336
	Federal net operating loss carryforwards	—			1,926
	State net operating loss carryforwards	24,354			23,677
	Other real estate owned	7,878			22,153
	Stock options and restricted stock	5,816			5,808
	Loans	6,833			8,628
	Deferred compensation	8,423			6,129
	Tax credit carryforwards	13,233			15,491
	Bonus accrual	4,739			4,438
	Merger and non-compete accrual	623			865
	Other items	1,222			1,343
	Total deferred tax asset	117,539			140,794
	Valuation allowance	—			—
	Total deferred tax asset, net of valuation allowance	117,539			140,794
	Deferred tax liability:
	Premises and equipment	(118,000		)	(116,780		)
	Deferred income from FDIC-assisted transactions	(48,272		)	(50,565		)
	Investment securities	(5,030		)	(5,573		)
	FHLB stock dividends	(2,441		)	(2,774		)
	Core deposit intangible	(2,918		)	(2,669		)
	Other items	(3,799		)	(3,673		)
	Total deferred tax liability	(180,460		)	(182,034		)
	Net deferred tax liability	(62,921		)	(41,240		)
	Net unrealized holding gain on investment securities available for sale	(5,354		)	(23,431		)
	Net deferred tax liability	$	(68,275	)	$	(64,671	)
	The Company’s state net operating loss carryforwards totaled $450.7 million at December 31, 2013 and begin to expire in 2015 through 2027.  In January of 2011, the State of Illinois enacted legislation suspending the utilization of net operating loss carryforwards. For Illinois purposes, no carryover deduction is allowed for any taxable year ending after December 31, 2010 and prior to December 31, 2012, and no carryover deduction can exceed $100,000 for any taxable year ending on or after December 31, 2012 and prior to December 31, 2014. Further, the legislation extended the carryover period for Illinois net operating losses by the number of taxable years in which carryover deductions are disallowed or limited.  The Company's tax credit carryforwards include federal alternative minimum tax credits of $12.4 million with an indefinite carryforward period and general business credits of $700 thousand with expiration dates occurring in 2028 through 2033. Management has determined that is more likely than not that the deferred tax assets, including the net operating loss carryforwards, as of December 31, 2013, will be realized and that no valuation allowance is required.
	Income taxes attributable to continuing operations consist of (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Current expense (benefit):
	Federal	$	12,234		$	15,075		$	713
	State	5,576			6,225			(611		)
	Foreign	—			—			—
		17,810			21,300			102
	Deferred expense	21,681			15,177			5,166
		$	39,491		$	36,477		$	5,268
	The reconciliation between the statutory federal income tax rate of 35% and the effective tax rate on income from continuing operations follows (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Federal income tax expense at expected statutory rate	$	48,281		$	44,398		$	15,398
	Increase (decrease) due to:
	Tax exempt income, net	(14,200		)	(12,539		)	(8,162		)
	State tax benefit resulting from change in tax rate	—			—			(2,100		)
	State tax expense net of federal impact	6,508			5,014			1,703
	Nonincludable increase in cash surrender value of life insurance	(1,111		)	(1,177		)	(1,529		)
	Nondeductible merger expense	591			—			—
	Adjustment of tax contingency reserves	(24		)	14			35
	Other items, net	(554		)	767			(77		)
	Income tax expense	$	39,491		$	36,477		$	5,268
	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, 2013 to December 31, 2013 is as follows (in thousands):
		Unrecognized Tax Benefit			Interest on unrecognized			Total Unrecognized Tax
		Without Interest			Tax Benefit			Benefit Including Interest
	Balance at January 1, 2013	$	95		$	9		$	104
	Increases for tax positions of prior years	15			5			20
	Benefits recognized	(37		)	(7		)	(44		)
	Balance at December 31, 2013	$	73		$	7		$	80
	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 2010 tax return year and forward.  The Company’s various state income tax returns are generally open for the 2010 tax return year and forward based on individual state statutes of limitation.  The Company is not currently under examination by any taxing authority.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
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, 2013 and 2012, the following financial instruments were outstanding, the contractual amounts of which represent off-balance sheet credit risk (in thousands):
		Contractual Amount
		2013		2012
	Commitments to extend credit:
	Home equity lines	$	208,581	$	239,771
	Other commitments	1,214,391		911,166
	Letters of credit:
	Standby	69,556		66,247
	Commercial	708		465
	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, 2013, the maximum remaining term for any standby letters of credit matures on December 31, 2021.  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, 2013, 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 $3.6 million to $70.3 million from $66.7 million at December 31, 2012.  Of the $70.3 million in commitments outstanding at December 31, 2013, approximately $63.8 million of the letters of credit have been issued or renewed since December 31, 2012.
	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.
	As of December 31, 2013, the Company had approximately $2.0 million in capital expenditure commitments outstanding which relate to various projects to renovate existing branches.
	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, 2013, approximately 27% 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, 2013. The distribution of commitments to extend credit approximates the distribution of loans outstanding.  Standby letters of credit are granted primarily to commercial borrowers. 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.
	On July 26, 2013, an action captioned James Sullivan v. Taylor Capital Group, Inc., et al., Case No. 2013-CH17751 (the “Sullivan Action”) was commenced against Taylor Capital, the board of directors of Taylor Capital (the “Taylor Capital Board”), and MB Financial (collectively, the “Defendants”) in the Circuit Court of Cook County, Illinois (the “Court”), alleging that the Taylor Capital Board breached its fiduciary duties in connection with the pending MB Financial/Taylor Capital merger (the “Merger”) and that MB Financial aided and abetted those breaches of fiduciary duty. On August 8, 2013, a stockholder class action captioned Dennis Panozzo v. Taylor Capital Group, Inc., et. al., Case No. 2013-CH-18546 (the “Panozzo Action”) was commenced against the Defendants in the Court making similar allegations in connection with the Merger. Subsequently, on September 10, 2013, the Sullivan Action and the Panozzo Action were consolidated pursuant to Court order under the first-filed Sullivan Action, Case No. 2013-CH17751 (as so consolidated, the “Action”). On October 24, 2013, the plaintiffs in the Action (the “Plaintiffs”) filed a consolidated amended class action complaint, alleging that the Taylor Capital Board breached its fiduciary duties in connection with the Merger, including by making incomplete and misleading disclosures concerning the Merger, and that MB Financial aided and abetted those breaches of fiduciary duty.
	On February 17, 2014, solely to eliminate the costs, risks, burden, distraction and expense of further litigation and to put the claims that were or could have been asserted to rest, the Defendants entered into a memorandum of understanding (the “MOU”) with the Plaintiffs regarding the settlement of the Action pursuant to which Taylor Capital and MB Financial agreed to make certain supplemental disclosures concerning the Merger, which each of Taylor Capital and MB Financial did in a Current Report on Form 8-K filed by each company on February 18, 2014 (the “Form 8-Ks”). The MOU also provides that, solely for purposes of settlement, the Court will certify a class consisting of all persons who were record or beneficial stockholders of Taylor Capital when the Merger was approved by the Taylor Capital Board or any time thereafter (the “Class”). In addition, the MOU provides that, subject to approval by the Court after notice to the members of the Class (the “Class Members”), the Action will be dismissed with prejudice and all claims that the Class Members may possess with regard to the Merger, with the exception of claims for statutory appraisal, will be released. In connection with the settlement, the Plaintiffs’ counsel have expressed their intention to seek an award by the Court of attorneys’ fees and expenses. The amount of the award to the Plaintiffs’ counsel will ultimately be determined by the Court. This payment will not affect the amount of merger consideration to be paid by MB Financial or that any Taylor Capital stockholder will receive in the Merger. There can be no assurance that the parties will ultimately enter into a definitive settlement agreement or that the Court will approve the settlement even if the parties enter into such an agreement. In the absence of either event, the proposed settlement as contemplated by the MOU may be terminated.
	The Defendants continue to believe that the Action is without merit, have vigorously denied, and continue to vigorously deny, all of the allegations of wrongful or actionable conduct asserted in the Action, and the Taylor Capital Board vigorously maintains that it diligently and scrupulously complied with its fiduciary duties, that the joint proxy statement/prospectus dated January 14, 2014 mailed to the stockholders of Taylor Capital and MB Financial is complete and accurate in all material respects and that no further disclosure is required under applicable law. The Defendants are entering into the MOU and the contemplated settlement solely to eliminate the costs, risks, burden, distraction and expense of further litigation and to put the claims that were or could have been asserted to rest. Nothing in the MOU, any settlement agreement or any public filing, including the Form 8-Ks, shall be deemed an admission of the legal necessity of filing or the materiality under applicable laws of any of the additional information contained therein or in any public filing associated with the proposed settlement of the Action.
	Based on information currently available, consultations with counsel and established reserves, management believes that the eventual outcome of this litigation will not have a material adverse effect on the Company's consolidated financial position or results of operations.

Regulatory_Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2013
Regulatory Matters	'
Regulatory Matters	'
	Regulatory Matters
	The Company’s primary source of cash is dividends from its bank subsidiary.  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 are subject as of December 31, 2013 and 2012.
	As of December 31, 2013, the most recent regulatory notification categorized the bank subsidiary as “well capitalized” under the regulatory framework for prompt corrective action.  To be categorized as “well capitalized,” the bank subsidiary must maintain the total risk-based, Tier 1 risk-based, 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 (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, 2013
	Total capital (to risk-weighted assets):
	Consolidated	$	1,106,541	16.53	%	$	535,430	8	%	N/A		N/A
	MB Financial Bank	974,189		14.59		534,004		8		$	667,505	10	%
	Tier 1 capital (to risk-weighted assets):
	Consolidated	1,022,512		15.28	%	267,715		4	%	N/A		N/A
	MB Financial Bank	890,380		13.34		267,002		4		400,503		6	%
	Tier 1 capital (to average assets):
	Consolidated	1,022,512		11.22	%	364,587		4	%	N/A		N/A
	MB Financial Bank	890,380		9.79		363,904		4		454,880		5	%
	As of December 31, 2012
	Total capital (to risk-weighted assets):
	Consolidated	$	1,059,357	16.62	%	$	509,885	8	%	N/A		N/A
	MB Financial Bank	983,817		15.49		508,016		8		$	635,021	10	%
	Tier 1 capital (to risk-weighted assets):
	Consolidated	939,087		14.73	%	254,942		4	%	N/A		N/A
	MB Financial Bank	863,836		13.6		254,008		4		381,012		6	%
	Tier 1 capital (to average assets):
	Consolidated	939,087		10.5	%	357,906		4	%	N/A		N/A
	MB Financial Bank	863,836		9.68		356,984		4		446,230		5	%
	N/A — not applicable

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
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 a 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 inputs.
	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.
	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.
	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. We also obtain dealer quotations for these derivatives for comparative purposes to assess the reasonableness of the model valuations. We also offer 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.
	The following table summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of December 31, 2013 and 2012, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (in thousands):
			Total				Quoted Prices in				Significant Other				Significant
							Active Markets for				Observable Inputs				Unobservable Inputs
							Identical Assets				(Level 2)				(Level 3)
							(Level 1)
	2013
	Financial assets
	Securities available for sale:
	U.S. Government sponsored agencies and enterprises		$	52,068			$	—			$	52,068			$	—
	States and political subdivisions		19,143				—				19,143				—
	Residential mortgage-backed securities		701,233				—				700,542				691
	Commercial mortgage-backed securities		52,941				—				52,941				—
	Corporate bonds		283,070				—				277,905				5,165
	Equity securities		10,457				10,457				—				—
	Loans held for sale		629				—				629				—
	Assets held in trust for deferred compensation		10,679				10,679				—				—
	Derivative financial instruments		18,645				—				18,645				—
	Financial liabilities
	Other liabilities (1)		10,569				10,569				—				—
	Derivative financial instruments		18,632				—				18,632				—
	2012
	Financial assets
	Securities available for sale:
	U.S. Government sponsored agencies and enterprises		$	41,315			$	—			$	41,315			$	—
	States and political subdivisions		725,019				—				725,019				—
	Residential mortgage-backed securities		939,202				—				938,354				848
	Commercial mortgage-backed securities		54,126				—				54,126				—
	Corporate bonds		96,674				—				91,451				5,223
	Equity securities		11,835				11,835				—				—
	Loans held for sale		7,492				—				7,492				—
	Assets held in trust for deferred compensation		7,746				7,746				—				—
	Derivative financial instruments		29,096				—				29,096				—
	Financial liabilities
	Other liabilities (1)		7,746				7,746				—				—
	Derivative financial instruments		29,055				—				29,055				—
	(1) Liabilities associated with assets held in trust for deferred compensation
	The following table presents 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			Valuation	Unobservable
		December 31, 2013			Technique	Input	Range
	Residential mortgage-backed securities	$	691		Discounted cash flows	Constant pre-payment rates
						(CPR) assumption	1% - 3% CPR
	Corporate bonds	5,165			Discounted cash flows	Credit assumption	20% Loss
	The Company did not have any transfers between Level 1 and Level 2 of the fair value hierarchy during the year ended December 31, 2013. 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
			2013				2012
	Balance, beginning of period		$	6,071			$	6,992
	Other comprehensive income		(44		)		81
	Principal payments		(157		)		(885		)
Impairment charge		(14		)		(117		)
Balance, ending of period		$	5,856			$	6,071
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 (approximately 85%), 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 possible loan 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.  During the year ended December 31, 2012, the Company recognized branch impairment charges of $2.2 million caused by the decision to close branches in that year.  The fair value of the branch was estimated using Level 3 inputs based on internal appraisals.
Assets measured at fair value on a nonrecurring basis as of December 31, 2013 and 2012 are included in the table below (in thousands):
		Total				Quoted Prices in Active				Significant Other				Significant
						Markets for Identical				Observable Inputs				Unobservable Inputs
						Assets (Level 1)				(Level 2)				(Level 3)
2013
Financial assets:
Impaired loans		$	77,497			$	—			$	—			$	77,497
Non-financial assets:
Foreclosed assets		44,601				—				—				44,601
2012
Financial assets:
Impaired loans		$	62,258			$	—			$	—			$	62,258
Non-financial assets:
Foreclosed assets		60,228				—				—				60,228
Long-lived assets		2,314				—				—				2,314
The following table presents additional information about the unobservable inputs used in the fair value measurement of 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	Unobservable
	December 31, 2013			Technique	Input	Range
Impaired loans	$	77,497		Appraisal of collateral	Appraisal adjustments - sales costs	5% - 10%
Foreclosed assets	44,601			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, interest bearing deposits with banks and federal funds sold: 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 a 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.
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, 2013
		Carrying Amount				Estimated Fair Value			Quoted Prices in Active			Significant Other			Significant
									Markets for Identical			Observable Inputs			Unobservable Inputs
									Assets (Level 1)			(Level 2)			(Level 3)
Financial Assets:
Cash and due from banks		$	205,193			$	205,193		$	205,193		$	—		$	—
Interest bearing deposits with banks		268,266				268,266			268,266			—			—
Federal funds sold		42,950				42,950			42,950			—			—
Investment securities available for sale		1,118,912				1,118,912			10,457			1,102,599			5,856
Investment securities held to maturity		1,182,533				1,198,929			—			1,198,929			—
Non-marketable securities - FHLB and FRB stock		51,417				51,417			—			—			51,417
Loans held for sale		629				629			—			629			—
Loans, net		5,600,805				5,583,759			—			—			5,583,759
Accrued interest receivable		36,593				36,593			36,593			—			—
Derivative financial instruments		18,645				18,645			—			18,645			—
Financial Liabilities:
Non-interest bearing deposits		$	2,375,863			$	2,375,863		$	2,375,863		$	—		$	—
Interest bearing deposits		5,005,396				5,012,928			—			—			5,012,928
Short-term borrowings		493,389				493,384			—			—			493,384
Long-term borrowings		62,159				66,301			—			—			66,301
Junior subordinated notes issued to capital trusts		152,065				101,247			—			—			101,247
Accrued interest payable		2,042				2,042			2,042			—			—
Derivative financial instruments		18,632				18,632			—			18,632			—
		December 31, 2012
		Carrying Amount				Estimated Fair Value			Quoted Prices in Active			Significant Other			Significant
									Markets for Identical			Observable Inputs			Unobservable Inputs
									Assets (Level 1)			(Level 2)			(Level 3)
Financial Assets:
Cash and due from banks		$	176,010			$	176,010		$	176,010		$	—		$	—
Interest bearing deposits with banks		111,533				111,533			111,533			—			—
Investment securities available for sale		1,868,171				1,868,171			11,835			1,850,265			6,071
Investment securities held to maturity		493,421				535,681			—			535,681			—
Non-marketable securities - FHLB and FRB stock		55,385				55,385			—			—			55,385
Loans held for sale		7,492				7,492			—			7,492			—
Loans, net		5,642,726				5,659,598			—			—			5,659,598
Accrued interest receivable		36,040				36,040			36,040			—			—
Derivative financial instruments		29,096				29,096			—			29,096			—
Financial Liabilities:
Non-interest bearing deposits		$	2,164,547			$	2,164,547		$	2,164,547		$	—		$	—
Interest bearing deposits		5,378,150				5,399,709			—			—			5,399,709
Short-term borrowings		220,602				220,683			—			—			220,683
Long-term borrowings		116,050				117,809			—			—			117,809
Junior subordinated notes issued to capital trusts		152,065				104,009			—			—			104,009
Accrued interest payable		2,828				2,828			2,828			—			—
Derivative financial instruments		29,055				29,055			—			29,055			—

Stock_Incentive_Plans

Stock Incentive Plans	12 Months Ended
	Dec. 31, 2013
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,
		2013				2012				2011
	Total cost of share-based payment plans during the year	$	5,456			$	4,806			$	4,836
	Amount of related income tax benefit recognized in income	$	2,159			$	1,918			$	1,972
	The Company adopted the Omnibus Incentive Plan (the “Omnibus Plan”) in 1997.  In June 2011, the Company’s stockholders approved an amendment and restatement of the Omnibus Plan to add 2,300,000 authorized shares for a total of 8,300,000 shares of common stock for issuance to directors, officers, and employees of the Company or any of its subsidiaries.  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.  As of December 31, 2013, there were 1,615,377 shares available for future grants.
	Annual equity-based incentive awards are typically granted to selected officers and employees mid-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, 2013:
		Number of			Weighted				Weighted		Aggregate
		Options			Average				Average		Intrinsic
					Exercise				Remaining		Value
					Price				Contractual		(in thousands)
									Term
									(in years)
	Options outstanding as of December 31, 2012	2,739,753			$	27.34
	Granted	225,269			27.34
	Exercised	(381,417	)		25.11
	Expired or cancelled	(118,690	)		31.13
	Forfeited	(21,163	)		20.04
	Options outstanding as of December 31, 2013	2,443,752			$	27.57			4.71		$	14,980
	Options exercisable as of December 31, 2013	1,766,966			$	29.93			3.43		$	7,761
	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, 2013, 2012, and 2011:
		For the Years Ended December 31,
		2013				2012				2011
	Risk-free interest rate	1.92		%		1.02		%		1.95		%
	Expected volatility of Company’s stock	25.18		%		27.17		%		43.72		%
	Expected dividend yield	1.73		%		2		%		1.48		%
	Expected life of options (years)	5.6				5.7				5.8
	Weighted average fair value per option of options granted during the year	$	5.88			$	4.23			$	7.57
	The total intrinsic value of options exercised during the years ended December 31, 2013, 2012, and 2011 was $1.3 million, $203 thousand, and $314 thousand, respectively.
	The following is a summary of changes in restricted shares and units for the year ended December 31, 2013:
		Number of			Weighted
		Shares			Average
					Grant Date
					Fair Value
	Shares and Units Outstanding at December 31, 2012	634,211			$	18.82
	Granted	272,152			26.92
	Vested	(203,495	)		16.78
	Forfeited	(17,149	)		20.86
	Shares and Units Outstanding at December 31, 2013	685,719			$	22.59
	The total intrinsic value of restricted shares that vested during the years ended December 31, 2013, 2012, and 2011 was $5.8 million, $6.2 million, and $2.2 million, respectively.
	The Company issued 56,752 and 65,333 market-based restricted stock units in 2013 and 2012, 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 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 of issuance.
	The Company issued 92,717 shares and 66,193 shares of market-based restricted stock in 2011 and 2010, respectively.  The market component of the vesting terms for each award requires that, for ten consecutive trading days, the closing price of the Company’s stock be at least $27.00 for awards issued in 2011 and $25.80 for awards issued in 2010.  The market components for awards issued in 2011 and 2010 have been satisfied as of December 31, 2013. Awards issued in 2011 will vest in full in 2014, on the third anniversary of the grant date. Awards issued in 2010 vested in full in 2013. A Monte Carlo simulation model was used to value the market-based restricted stock awards at the time of issuance.
	Effective January 1, 2010, the Company began issuing shares of common stock under the Omnibus Plan as Salary Stock, classified as other stock-based awards, to certain executive officers. This stock is fully vested as of the grant date and the related expense is included in salaries and employee benefits on the Consolidated Statements of Operations. Holders of Salary Stock have all of the rights of a stockholder, including the right to vote the shares and the right to receive any dividends that may be paid thereon. As a condition of receiving the Salary Stock, the holders entered into agreements with the Company providing that they may not sell or otherwise transfer the shares of Salary Stock for two years, except in the event of disability or death.  During the three months ended March 31, 2013, the Company issued 876 shares of Salary Stock at a weighted average issuance price of $22.39 and subsequently ended the issuance of new shares of Salary Stock. During the year ended December 31, 2012, the Company issued 14,855 shares of Salary Stock at a weighted average issuance price of $20.10.
	As of December 31, 2013, there was $12.6 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, 2013, the weighted-average period over which the unrecognized compensation expense is expected to be recognized was approximately 2.7 years.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2013
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 our 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 income statement.
	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 net amount payable for December 31, 2013 was approximately $25 thousand, and the net amount payable for December 31, 2012 was approximately $30 thousand.  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, 2013, the Company’s credit exposure relating to interest rate swaps was approximately $17.4 million, which is secured by the underlying collateral on customer loans.
	The Company also enters into mortgage banking derivatives which are designated as non-designated 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 $238 thousand at December 31, 2013.  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.
	The Company’s derivative financial instruments are summarized below as of December 31, 2013 and 2012 (in thousands):
		Asset Derivatives											Liability Derivatives
		December 31, 2013						December 31, 2012					December 31, 2013					December 31, 2012
		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)	$	—		$	—		$	—		$	—	$	238	$	(23	)	$	3,707		$	(94	)
	Stand-alone derivative instruments: (2)
	Interest rate swap contracts	550,883			17,298			460,956			27,740		551,798		(17,350		)	462,012			(27,832		)
	Interest rate options contracts	83,907			323			70,346			157		84,953		(323		)	70,346			(157		)
	Foreign exchange contracts	31,361			1,006			20,033			1,062		47,760		(935		)	19,337			(961		)
	Mortgage banking derivatives	1,783			18			11,400			137		250		(1		)	4,000			(11		)
	Total non-hedging derivative instruments	667,934			18,645			562,735			29,096		684,761		(18,609		)	555,695			(28,961		)
	Total	$	667,934		$	18,645		$	562,735		$	29,096	$	684,999	$	(18,632	)	$	559,402		$	(29,055	)
	(1) Hedged fixed-rate commercial real estate loans
	(2) These portfolio swaps are not designated as hedging instruments under ASC Topic 815.
	Amounts included in the other income in the consolidated statements of operations related to derivative financial instruments were as follows (in thousands):
		Years Ended
		December 31,
		2013			2012			2011
	Derivative instruments designated as hedges of fair value:
	Interest rate swap contracts	$	9		$	(15	)	$	(166	)
	Stand-alone derivative instruments:
	Interest rate swap contracts	40			30			163
	Interest rate options contracts	—			—			—
	Foreign exchange contracts	(30		)	67			8
	Mortgage banking derivatives	(109		)	96			31
	Total non-hedging derivative instruments	(99		)	193			202
	Total	$	(90	)	$	178		$	36
	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, 2013 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	$	5,792		$	—		$	5,792		$	11,904	$	—	$	11,904
	Foreign currency forward contracts	80			—			80			848		—		848
	Mortgage banking derivatives	3			—			3			1		—		1
	Total derivatives	5,875			—			5,875			12,753		—		12,753
	Repurchase agreements	—			—			—			193,389		—		193,389
	Total	$	5,875		$	—		$	5,875		$	206,142	$	—	$	206,142
		Financial Assets											Financial Liabilities
		Net Amount Recognized			Financial Instruments			Collateral			Net Amount		Net Amount Recognized		Financial Instruments			Collateral			Net Amount
	Derivatives:
	Counterparty A	$	883		$	(883	)	$	—		$	—	$	10,669	$	(883	)	$	(9,786	)	$	—
	Counterparty B	1,836			(412		)	—			1,424		412		(412		)	—			—
	Counterparty C	2,380			(1,612		)	—			768		1,612		(1,612		)	—			—
	Other counterparties	776			(5		)	—			771		60		(5		)	—			55
	Total derivatives	5,875			(2,912		)	—			2,963		12,753		(2,912		)	(9,786		)	55
	Repurchase agreements	—			—			—			—		193,389		—			(193,389		)	—
	Total	$	5,875		$	(2,912	)	$	—		$	2,963	$	206,142	$	(2,912	)	$	(203,175	)	$	55
	Information about the Company's financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2012 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	$	192		$	—		$	192		$	27,890	$	—	$	27,890
	Foreign currency forward contracts	43			—			43			929		—		929
	Mortgage banking derivatives	1			—			1			11		—		11
Total derivatives	236			—			236			28,830		—		28,830
Repurchase agreements	—			—			—			208,242		—		208,242
Total	$	236		$	—		$	236		$	237,072	$	—	$	237,072
	Financial Assets											Financial Liabilities
	Net Amount Recognized			Financial Instruments			Collateral			Net Amount		Net Amount Recognized		Financial Instruments			Collateral			Net Amount
Derivatives:
Counterparty A	$	68		$	(68	)	$	—		$	—	$	25,497	$	(68	)	$	(25,429	)	$	—
Counterparty B	84			(84		)	—			—		633		(84		)	(549		)	—
Counterparty C	36			(36		)	—			—		2,305		(36		)	(2,269		)	—
Other counterparties	48			(42		)	—			6		395		(42		)	(298		)	55
Total derivatives	236			(230		)	—			6		28,830		(230		)	(28,545		)	55
Repurchase agreements	—			—			—			—		208,242		—			(208,242		)	—
Total	$	236		$	(230	)	$	—		$	6	$	237,072	$	(230	)	$	(236,787	)	$	55

Operating_Segments_Notes

Operating Segments (Notes)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Operating Segments	'
	Operating Segments
	The Company's operations consist of two reportable operating segments: banking and leasing. The Company offers different products and services through its two segments, and the regulatory environment is significantly different for banking compared to leasing. The accounting policies of the segments are generally the same as those described in Note 1. Significant Accounting Policies.
	The banking segment generates its revenues primarily from its lending and deposit gathering 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 dependent on changes in its 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 customers and depositors.  These laws and regulations govern such areas as capital, permissible activities, allowance for loan 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 offered through the Company's leasing subsidiaries, LaSalle Systems Leasing, Inc. and Celtic Leasing Corp. The leasing subsidiaries invest directly in equipment that we lease (referred to as direct finance, leveraged or operating leases) to "Fortune 1000," large middle-market companies and healthcare 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 equipment. The leasing subsidiaries also specialize in selling third party equipment maintenance contracts to large companies.
	Net interest income for the leasing segment includes adjustments based on the Company's internal funds transfer pricing model as well as interest on loans originated for the sole purpose of funding equipment purchases related to leases at the Company's lease subsidiaries. The provision for credit losses and non-interest expense for the leasing segment includes adjustments for internal allocations of certain expenses.
	The following table presents summary financial information for the reportable segments (in thousands):
		Banking			Leasing			Consolidated
	Year ended December 31,
	2013
	Net interest income	$	267,131		$	5,205		$	272,336
	Provision for credit losses	(6,167		)	363			(5,804		)
	Non-interest income	94,600			59,794			154,394
	Non-interest expense	259,753			34,835			294,588
	Income tax expense	28,201			11,290			39,491
	Net income	$	79,944		$	18,511		$	98,455
	Total assets	$	9,225,610		$	415,817		$	9,641,427
	Year ended December 31,
	2012
	Net interest income	$	290,881		$	1,907		$	292,788
	Provision for credit losses	(9,035		)	135			(8,900		)
	Non-interest income	95,449			33,744			129,193
	Non-interest expense	284,452			19,578			304,030
	Income tax expense	30,780			5,697			36,477
	Net income	$	80,133		$	10,241		$	90,374
	Total assets	$	9,203,837		$	367,968		$	9,571,805
	Year ended December 31,
	2011
	Net interest income	$	324,356		$	917		$	325,273
	Provision for credit losses	120,808			(58		)	120,750
	Non-interest income	95,936			26,783			122,719
	Non-interest expense	267,455			15,791			283,246
	Income tax expense	1,182			4,086			5,268
	Net income	$	30,847		$	7,881		$	38,728
	Total assets	$	9,623,039		$	210,033		$	9,833,072

Condensed_Parent_Company_Finan

Condensed Parent Company Financial Information	12 Months Ended
	Dec. 31, 2013
Condensed Financial Information of Parent Company Only 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,
		2013			2012
	Assets
	Cash	$	122,001		$	57,303
	Loans	—			6,960
	Investments in subsidiaries	1,340,641			1,346,590
	Other assets	24,505			21,796
	Total assets	$	1,487,147		$	1,432,649
	Liabilities and Stockholders’ Equity
	Junior subordinated notes issued to capital trusts	$	152,065		$	152,065
	Other liabilities	8,400			4,814
	Stockholders’ equity	1,326,682			1,275,770
	Total liabilities and stockholders’ equity	$	1,487,147		$	1,432,649
	Statements of Operations
	(In thousands)
		Years Ended December 31,
		2013			2012			2011
	Dividends from subsidiaries	$	80,500		$	146,000		$	—
	Interest and other income	4,215			1,682			3,410
	Interest and other expense	7,143			7,117			6,248
	Income (loss) before income tax benefit and equity in undistributed net income (loss) of subsidiaries	77,572			140,565			(2,838		)
	Income tax benefit	(1,223		)	(2,192		)	(1,151		)
	Income (loss) before equity in undistributed net income of subsidiaries	78,795			142,757			(1,687		)
	Equity in undistributed net income (loss) of subsidiaries	19,660			(52,383		)	40,415
	Net income	98,455			90,374			38,728
	Dividends and discount accretion on preferred shares	—			3,269			10,414
	Net income available to common stockholders	$	98,455		$	87,105		$	28,314
	Statements of Cash Flows
	(In thousands)
		Years Ended December 31,
		2013			2012			2011
	Cash Flows From Operating Activities
	Net income	$	98,455		$	90,374		$	38,728
	Adjustments to reconcile net income to net cash provided by operating activities:
	Amortization of restricted stock awards	4,280			3,544			3,277
	Compensation expense for stock option grants	1,176			1,262			1,559
	Equity in undistributed net income of subsidiaries	(19,660		)	52,383			(40,415		)
	Change in other assets and other liabilities	(1,460		)	(5,064		)	8,275
	Net cash provided by operating activities	82,791			142,499			11,424
	Cash Flows From Investing Activities
	Net decrease in loans	6,960			21,010			18,009
	Net cash provided by investing activities	6,960			21,010			18,009
	Cash Flows From Financing Activities
	Treasury stock transactions, net	(1,672		)	(249		)	(1,149		)
	Stock options exercised	1,014			154			1,903
	Excess tax benefits from share-based payment arrangements	(325		)	(390		)	(53		)
	Dividends paid on common stock	(24,070		)	(7,101		)	(2,164		)
	Dividends paid on preferred stock	—			(3,239		)	(9,799		)
	Repurchase of preferred stock and warrant	—			(197,518		)	—
	Redemption of on junior subordinated notes issued to capital trusts	—			(6,186		)	—
	Net cash used in financing activities	(25,053		)	(214,529		)	(11,262		)
	Net increase (decrease) in cash	64,698			(51,020		)	18,171
	Cash:
	Beginning of year	57,303			108,323			90,152
	End of year	$	122,001		$	57,303		$	108,323

Preferred_Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Preferred Stock	'
	Preferred Stock
	The Series A Preferred Stock was issued as part of the Troubled Asset Relief Program (“TARP”) Capital Purchase Program of the United States Department of the Treasury (“Treasury”).  The Series A Preferred Stock qualified as Tier 1 capital and provided for cumulative dividends on the liquidation preference amount on a quarterly basis at a rate of 5% per annum for the first five years, and 9% per annum thereafter.  Concurrent with issuing the Series A Preferred Stock, the Company issued to the Treasury a 10 year warrant (the “Warrant”) to purchase 1,012,048 shares (subsequently reduced to 506,024 shares, as described below) of the Company’s Common Stock at an exercise price of $29.05 per share.
	On September 17, 2009, the Company completed a public offering of its common stock by issuing 12,578,125 shares of common stock for aggregate gross proceeds of $201.3 million.  The net proceeds to the Company after deducting underwriting discounts and commissions and offering expenses were approximately $190.9 million.  With the proceeds from this offering and the proceeds received by the Company from issuances pursuant to its Dividend Reinvestment and Stock Purchase Plan, the Company has received aggregate gross proceeds from “Qualified Equity Offerings” in excess of the $196.0 million aggregate liquidation preference amount of the Series A Preferred Stock.  As a result, the number of shares of the Company’s common stock underlying the Warrant was reduced by 50%, from 1,012,048 shares to 506,024 shares.
	On March 14, 2012, the Company repurchased all $196.0 million of the Series A Preferred Stock. On May 2, 2012, the Company repurchased the Warrant in full for approximately $1.5 million.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
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 losses; residual value of direct finance, leveraged, and operating leases; 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 available for sale	'
	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.  Gains and losses recognized on mortgage loans held for sale include the value of the mortgage servicing rights if the loan is sold with servicing retained by the Company.  Mortgage servicing rights are stratified based on the predominant risk characteristics of rates, terms, and the underlying loan types to measure its fair value.  The amount of impairment recognized is the amount by which the capitalized mortgage servicing rights for a stratum exceed their fair value.
Loans and leases	'
	Loans and leases: Loans are stated at the amount of unpaid principal reduced by the allowance for loan 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 at the sum of remaining minimum lease payments from lessees (less nonrecourse debt payments) plus estimated residual values less unearned lease income.  On a quarterly 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 nonaccrual loans and loans classified as a troubled debt restructuring. 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 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.
	Periodically, the Company will restructure a note into two separate notes (A/B structure), charging off the entire B portion of the note. The A note is structured with appropriate loan-to-value and cash flow coverage ratios that provide for a high likelihood of repayment. The A note is classified as a non-performing note until the borrower has displayed a historical payment performance for a reasonable time prior to and subsequent to the restructuring. A period of sustained repayment for at least six months generally is required to return the note to accrual status provided that management has determined that the performance is reasonably expected to continue. The A note will be classified as a restructured note (either performing or nonperforming) through the calendar year of the restructuring that the historical payment performance has been established.
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, and prevailing economic conditions that may affect the borrower’s ability to pay.  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 any loan committee.  Loans rated "one" represent those loans least likely to default and 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 the migration of loan risk ratings and historical default data over a multi-year period to develop our estimated default factors (EDFs).  The model tracks annual loan rating migrations by loan type and currently uses loan risk rating migrations for 13 years.  The migration data is adjusted by using average losses for an economic cycle (approximately 12 years) to develop EDFs by loan type, risk rating and maturity.  EDFs are updated annually in December.
	Estimated loan default factors are multiplied by individual loan balances in each risk-rating category and again multiplied by an historical loss given default estimate for each loan type (which incorporates estimated 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 adjustments for macroeconomic factors.  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 has shown to be a statistically reliable predictor of our credit losses relative to our long term average credit losses. We tested over 20 economic variables (U.S. manufacturing index, unemployment rate, U.S. GDP growth, etc.). We annually review this data to determine that such a relationship continues to exist. We currently use the following macroeconomic indicators in our macroeconomic factor computation:
	Commercial loans and lease loans:  Japanese bilateral dollar exchange, our prior period charge-off rates and the consumer confidence index.
	Commercial real estate loans and construction loans:  Prime rate, our prior period charge-off rates and the annual change in the U.S. commercial real estate index.
	Using the indicators noted above, a predicted charge-off percentage is calculated.  The predicted charge-off percentage is then compared to the cycle average charge-off percentage used in our EDF computation discussed above, and a macroeconomic adjustment factor is calculated.  The macroeconomic adjustment factor is applied to each commercial loan type.  Each year, we review the predictive nature of the macroeconomic factors by comparing actual charge-offs to the predicted model charge-offs, re-run our regression analysis and re-calibrate the macroeconomic factors as appropriate.
	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, most recently updated in December 2010. 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 by internally applying accepted appraisal methodologies to an older appraisal.  Accepted appraisal methodologies include:  income capitalization approach adjusting for changes in underlying leases, adjustments related to condominium projects with units sales, adjustments for loan fundings, and “As is” compared to “As Stabilized” valuations.
	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.
Loans acquired through transfer	'
	Acquired loans: Purchased loans acquired in a business combination 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 310-20 “Nonrefundable Fees and Other Costs” as these loans do not have evidence of credit deterioration since origination.
	•	Non-impaired loans (typically past-due loans, special mention loans and performing substandard loans) are accounted for in accordance with ASC 310-30 “Receivables - Loans and Debt Securities Acquired with Deteriorated Credit Quality” as 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 310-30 as they display significant credit deterioration since origination.
	In accordance with ASC 310-30, for both purchased non-impaired loans and purchased impaired loans, the difference between contractually required payments at acquisition and the cash flows expected to be collected is referred to as the non-accretable difference. This amount is not recognized as a yield adjustment or as a loss accrual or a valuation allowance. 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 when there is a reasonable expectation about the amount and timing of such cash flows.
	Increases in expected cash flows subsequent to the initial investment are recognized prospectively through adjustment of the yield net of any impact of the loss share agreement with the FDIC, if applicable, on the loan over its remaining estimated life. Decreases in expected cash flows are recognized immediately as impairment. If the Company does not have the information necessary to reasonably estimate cash flows to be expected, it may use the cost recovery method or cash basis method of income recognition. Valuation allowances on these impaired loans reflect only losses incurred after the acquisition (meaning the present value of all cash flows expected at acquisition that ultimately are not to be received).
	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 range from 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.
Other real estate owned (OREO)	'
	Other real estate owned (OREO): OREO includes real estate assets that have been received in satisfaction of debt.  OREO is initially recorded at fair value less estimated selling costs, which establishes the cost basis.  Subsequently, OREO 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 losses.  Subsequently, unrealized losses and realized gains and losses on sale are included in net loss recognized on other real estate owned.  Operating results from OREO are recorded separately on the income statement within other real estate expense, net.
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 at the unit level. As of December 31, 2013, the annual assessment date, the Company had two reporting units: banking and leasing. The Company did not recognize impairment losses during the year ended December 31, 2013.
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 the declining balance method over four to 15 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.
FDIC indemnification asset	'
	FDIC indemnification asset: As part of the Heritage, Benchmark, Broadway, and New Century transactions, MB Financial Bank entered into loss-share agreements with the FDIC. These agreements cover realized losses on loans and foreclosed real estate. 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 separately on the balance sheet.  The corresponding accretion is recorded separately on the income statement.  Although these assets are contractual receivables from the FDIC, there are no contractual interest rates.
	When cash flow estimates are adjusted downward for a particular loan pool, the FDIC indemnification asset is increased.  An allowance for loan losses is established for the impairment of the loans.  A provision for loan losses is recognized for the difference between the increase in the FDIC indemnification asset and the decrease in cash flows.
	When cash flow estimates are adjusted upward for a particular loan pool, the FDIC indemnification asset is decreased.  The difference between the decrease in the FDIC indemnification asset and the increase in cash flows is accreted over the estimated life of the loan pool.
	When cash flow estimates are adjusted downward for covered foreclosed real estate, the FDIC indemnification asset is increased.  A charge is recognized for the difference between the increase in the FDIC indemnification asset and the decrease in cash flows.
	When cash flow estimates are adjusted upward for covered foreclosed real estate, the FDIC indemnification asset is decreased.  Any write-down after the transfer to covered foreclosed real estate is reversed.
	In both scenarios, the claw-back liability will increase or decrease accordingly.
Preferred stock	'
	Preferred stock: Preferred stock callable at the option of the Company is initially recorded at the amount of proceeds received.  Any discount from the liquidation value is accreted to the expected call date and charged to retained earnings.  This accretion is recorded using the level-yield method.  Preferred dividends paid (declared and accrued) and any accretion is deducted from net income for computing income available to common stockholders and earnings per 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 income statement, and requires that a company must 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 income statement 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 Business Solutions, LLC (LBS), a subsidiary of LaSalle Systems Leasing, Inc., sells third party maintenance contracts to customers.  The maintenance is serviced by third party providers, with LBS maintaining no legal obligation under the contract to perform additional services.  Revenues are recorded net of cost of sales, as LBS is viewed as an agent under ASC Topic 605, 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.  ASC Topic 718 requires public companies to recognize compensation expense related to stock-based equity awards in their income statements.  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.
	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,
			2013		2012		2011
	Distributed earnings allocated to common stock		$	24,290	$	7,149	$	2,185
	Undistributed earnings		74,165		83,225		36,543
	Net income		98,455		90,374		38,728
	Less: preferred stock dividends and discount accretion		—		3,269		10,414
	Net income available to common stockholders		98,455		87,105		28,314
	Less: earnings and dividends allocated to participating securities		2		3		33
	Earnings allocated to common stockholders		$	98,453	$	87,102	$	28,281
	Weighted average shares outstanding for basic earnings per common share		54,509,612		54,270,297		54,057,158
	Dilutive effect of equity awards		484,253		235,679		280,122
	Weighted average shares outstanding for diluted earnings per common share		54,993,865		54,505,976		54,337,280
	Basic earnings per common share		$	1.81	$	1.61	$	0.52
	Diluted earnings per common share		1.79		1.6		0.52
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: (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. As of December 31, 2013, the Company had two reportable operating segments: banking and leasing.
New authoritative accounting guidance	'
	New authoritative accounting guidance:
	ASC Topic 805 “Business Combinations.” New authoritative accounting guidance under ASC Topic 805, “Business Combinations” amended prior guidance on the subsequent accounting for an indemnification asset recognized at the acquisition date as a result of a government-assisted (Federal Deposit Insurance Corporation) acquisition of a financial institution that includes a loss-sharing agreement. The new authoritative guidance requires that at each subsequent reporting date, an acquirer measure an indemnification asset on the same basis as the indemnified liability or asset, subject to any contractual limitations on its amount, and, for an indemnification asset that is not subsequently measured at fair value, management's assessment of the collectability of the indemnification asset. Any amortization of changes in value should be limited to the contractual term of the indemnification agreement (that is, the lesser of the term of the indemnification agreement and the remaining life of the indemnified assets). The Company adopted this new authoritative guidance on January 1, 2013, and it did not have an impact on the Company's statements of operations and financial condition.
	ASC Topic 210 “Disclosures about Offsetting Assets and Liabilities.” New authoritative accounting guidance under ASC Topic 210, “Disclosures about Offsetting Assets and Liabilities” amended prior guidance to require an entity to disclose both gross and net information about both instruments and transactions eligible for offset in the statement of financial position and instruments and transactions subject to an agreement similar to a master netting arrangement. The instruments and transactions would include derivatives, sale and repurchase agreements and reverse sale and repurchase agreements, and securities borrowing and securities lending arrangements. This new authoritative guidance was further amended to clarify the scope of offsetting disclosures. The Company adopted the new authoritative guidance on January 1, 2013, and it did not have an impact on the Company's statements of operations and financial condition. See disclosures in Note 20.
	ASC Topic 220 “Comprehensive Income.” New authoritative accounting guidance under ASC Topic 220, “Comprehensive Income” amended prior guidance to improve the reporting of reclassifications out of accumulated other comprehensive income by requiring an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present, either on the face of the statement or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income if the amount reclassified is required under U.S. GAAP. The Company adopted this new authoritative guidance on January 1, 2013, and it did not have an impact on the Company's statements of operations and financial condition.
	ASC Topic 815 “Derivatives and Hedging.” New authoritative accounting guidance under ASC Topic 815, “Derivatives and Hedging” amended prior guidance to permit the Fed Funds Effective Swap Rate (OIS) to be used as a U.S. benchmark interest rate for hedge accounting purposes, in addition to U.S. government treasury obligation rates and London Interbank Offered Rate swap rate. The amendments also remove the restriction on using different benchmark rates for similar hedges. The new authoritative guidance was effective prospectively for new and redesignated hedging relationships entered into on or after July 17, 2013 and it did not have an impact on the Company's statements of operations and financial condition.
	ASC Topic 740 “Income Taxes.” New authoritative accounting guidance under ASC Topic 740, “Income Taxes” amended prior guidance to include explicit guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. An unrecognized tax benefit, or a portion of an unrecognized tax benefit, should be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The new authoritative guidance will be for reporting periods after January 1, 2014 and is not expected to have an impact on the Company's statements of operations and financial condition.
	ASC Topic 310 "Receivables." New authoritative accounting guidance under ASC Topic 310, “Receivables” amended prior guidance to clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical
	possession of residential real estate property collateralizing a consumer mortgage loan, upon either (1) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure or (2) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additionally, the amendments require interim and annual disclosures. The new authoritative guidance will be for reporting periods after January 1, 2015 and is not expected to have an impact on the Company's statements of operations and financial condition.
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_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Reconciliation of the number of shares used in the calculation of basic and diluted earnings (loss) per common share, net income available to common stockholders, and earnings per 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,
		2013		2012		2011
	Distributed earnings allocated to common stock	$	24,290	$	7,149	$	2,185
	Undistributed earnings	74,165		83,225		36,543
	Net income	98,455		90,374		38,728
	Less: preferred stock dividends and discount accretion	—		3,269		10,414
	Net income available to common stockholders	98,455		87,105		28,314
	Less: earnings and dividends allocated to participating securities	2		3		33
	Earnings allocated to common stockholders	$	98,453	$	87,102	$	28,281
	Weighted average shares outstanding for basic earnings per common share	54,509,612		54,270,297		54,057,158
	Dilutive effect of equity awards	484,253		235,679		280,122
	Weighted average shares outstanding for diluted earnings per common share	54,993,865		54,505,976		54,337,280
	Basic earnings per common share	$	1.81	$	1.61	$	0.52
	Diluted earnings per common share	1.79		1.6		0.52

Business_Combinations_Tables

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Assets Acquired and Liabilities Assumed	'
	Estimated fair values of the assets acquired and liabilities assumed in the Celtic transaction, as of the closing date of the transaction were as follows (in thousands):
	Assets Acquired and Liabilities Assumed
	(Dollar Amounts in Thousands)
		Celtic
		December 28,
		2012
	ASSETS
	Cash and cash equivalents	$	31,647
	Investment securities available for sale	635
	Loans and leases	32,933
	Premises and equipment	81
	Goodwill	36,300
	Other intangibles	5,028
	Other assets	27,323
	Total assets	$	133,947
	LIABILITIES
	Accrued expenses and other liabilities	$	75,290
	Total liabilities	$	75,290
	Cash paid (received) on acquisition	$	58,657
	Net gain recorded on acquisition	$	—

Investment_Securities_Tables

Investment Securities (Tables)	12 Months Ended
	Dec. 31, 2013
Investments Securities [Abstract]	'
Summary investment holdings	'
	Carrying amounts and fair values of investment securities were as follows (in thousands):
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Gains			Losses
	December 31, 2013
	Available for Sale
	U.S. Government sponsored agencies and enterprises	$	50,486		$	1,704		$	(122	)	$	52,068
	States and political subdivisions	19,398			22			(277		)	19,143
	Residential mortgage-backed securities	696,415			8,555			(3,737		)	701,233
	Commercial mortgage-backed securities	50,891			2,050			—			52,941
	Corporate bonds	284,083			1,597			(2,610		)	283,070
	Equity securities	10,649			—			(192		)	10,457
		1,111,922			13,928			(6,938		)	1,118,912
	Held to Maturity
	States and political subdivisions	932,955			7,584			(4,366		)	936,173
	Residential mortgage-backed securities	249,578			13,178			—			262,756
		1,182,533			20,762			(4,366		)	1,198,929
	Total	$	2,294,455		$	34,690		$	(11,304	)	$	2,317,841
	December 31, 2012
	Available for Sale
	U.S. Government sponsored agencies and enterprises	$	38,605		$	2,710		$	—		$	41,315
	States and political subdivisions	679,991			45,571			(543		)	725,019
	Residential mortgage-backed securities	930,413			14,038			(5,249		)	939,202
	Commercial mortgage-backed securities	51,100			3,026			—			54,126
	Corporate bonds	97,014			213			(553		)	96,674
	Equity securities	11,398			447			(10		)	11,835
		1,808,521			66,005			(6,355		)	1,868,171
	Held to Maturity
	States and political subdivisions	237,563			21,039			—			258,602
	Residential mortgage-backed securities	255,858			21,221			—			277,079
		493,421			42,260			—			535,681
	Total	$	2,301,942		$	108,265		$	(6,355	)	$	2,403,852
Unrealized losses on investment securities and the fair value of the related securities	'
	Unrealized losses on investment securities and the fair value of the related securities at December 31, 2013 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	$	18,598		$	(122	)	$	—		$	—		$	18,598	$	(122	)
	States and political subdivisions	2,275			(166		)	4,748			(111		)	7,023		(277		)
	Residential mortgage-backed securities	232,807			(2,905		)	44,182			(832		)	276,989		(3,737		)
	Corporate bonds	122,344			(2,606		)	705			(4		)	123,049		(2,610		)
	Equity securities	10,457			(192		)	—			—			10,457		(192		)
		386,481			(5,991		)	49,635			(947		)	436,116		(6,938		)
	Held to Maturity
	States and political subdivisions	235,016			(4,330		)	1,301			(36		)	236,317		(4,366		)
	Totals	$	621,497		$	(10,321	)	$	50,936		$	(983	)	$	672,433	$	(11,304	)
	Unrealized losses on investment securities and the fair value of the related securities at December 31, 2012 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
	States and political subdivisions	$	57,540		$	(543	)	$	—		$	—		$	57,540	$	(543	)
	Residential mortgage-backed securities	270,539			(5,083		)	16,434			(166		)	286,973		(5,249		)
	Corporate bonds	58,241			(553		)	—			—			58,241		(553		)
	Equity securities	30			(10		)	—			—			30		(10		)
	Totals	$	386,350		$	(6,189	)	$	16,434		$	(166	)	$	402,784	$	(6,355	)
Summary of realized gains on the sale of investment securities available for sale	'
		For the Years Ended December 31,
		2013			2012			2011
	Realized gains	$	15		$	787		$	647
	Realized losses	(2		)	(8		)	(7		)
	Impairment charges	(14		)	(224		)	—
	Net (losses) gains	$	(1	)	$	555		$	640
Schedule of remaining contractual maturities of securities included in the securities portfolio	'
		Amortized			Fair
	(In thousands)	Cost			Value
	Available for sale:
	Due in one year or less	$	504		$	505
	Due after one year through five years	337,107			337,675
	Due after five years through ten years	7,676			7,582
	Due after ten years	8,680			8,519
	Equity securities	10,649			10,457
	Residential and commercial mortgage-backed securities	747,306			754,174
		1,111,922			1,118,912
	Held to maturity:
	Due in one year or less	27,708			27,715
	Due after one year through five years	252,967			254,608
	Due after five years through ten years	121,269			121,128
	Due after ten years	531,011			532,722
	Residential mortgage-backed securities	249,578			262,756
		1,182,533			1,198,929
	Total	$	2,294,455		$	2,317,841

Loans_Tables

Loans (Tables)	12 Months Ended
	Dec. 31, 2013
Receivables [Abstract]	'
Schedule of composition of loans	'
	Loans consist of the following at (in thousands):
			December 31,
			2013				2012
	Commercial		$	1,281,377			$	1,220,472
	Commercial collateralized by assignment of lease payments		1,494,188				1,303,020
	Commercial real estate		1,647,700				1,761,832
	Residential real estate		314,440				314,359
	Construction real estate		141,253				110,261
	Indirect vehicle		262,632				208,633
	Home equity		268,289				305,186
	Other consumer		66,952				93,317
	Gross loans, excluding covered loans		5,476,831				5,317,080
	Covered loans		235,720				449,850
	Total loans(1)		$	5,712,551			$	5,766,930
	(1)          Gross loan balances at December 31, 2013 and 2012 are net of unearned income, including net deferred loan fees of $1.9 million and $1.1 million, respectively.
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, 2013 and 2012 (in thousands):
			Current				30-59 Days				60-89 Days				Loans Past Due			Total				Total
							Past Due				Past Due				90 Days or More			Past Due
	31-Dec-13
	Commercial		$	1,273,302			$	5,952			$	626			$	1,497		$	8,075			$	1,281,377
	Commercial collateralized by assignment of lease payments		1,489,391				3,841				656				300			4,797				1,494,188
	Commercial real estate:
	Healthcare		213,665				—				—				3,064			3,064				216,729
	Industrial		372,975				5,465				—				1,404			6,869				379,844
	Multifamily		302,456				3,078				181				2,226			5,485				307,941
	Retail		334,198				328				2,816				7,258			10,402				344,600
	Office		155,936				—				—				2,066			2,066				158,002
	Other		233,464				4,898				259				1,963			7,120				240,584
	Residential real estate		302,362				1,422				1,030				9,626			12,078				314,440
	Construction real estate		138,563				391				—				2,299			2,690				141,253
	Indirect vehicle		259,488				2,210				657				277			3,144				262,632
	Home equity		257,219				1,725				2,165				7,180			11,070				268,289
	Other consumer		66,866				81				1				4			86				66,952
	Gross loans, excluding covered loans		5,399,885				29,391				8,391				39,164			76,946				5,476,831
	Covered loans		135,717				902				3,346				95,755			100,003				235,720
	Total loans (1)		$	5,535,602			$	30,293			$	11,737			$	134,919		$	176,949			$	5,712,551
	Nonperforming loan aging		$	56,339			$	14,325			$	3,283			$	32,614		$	50,222			$	106,561
	Non-covered loans related to FDIC transactions (2)		$	13,541			$	163			$	391			$	6,550		$	7,104			$	20,645
	December 31, 2012
	Commercial		$	1,215,957			$	639			$	754			$	3,122		$	4,515			$	1,220,472
	Commercial collateralized by assignment of lease payments		1,288,341				11,252				2,847				580			14,679				1,303,020
	Commercial real estate:
	Healthcare		192,039				—				—				3,238			3,238				195,277
	Industrial		402,813				548				424				7,700			8,672				411,485
	Multifamily		353,966				1,282				—				3,103			4,385				358,351
	Retail		375,900				6,933				518				9,331			16,782				392,682
	Office		186,665				742				280				1,125			2,147				188,812
	Other		210,456				851				1,837				2,081			4,769				215,225
	Residential real estate		306,927				382				1,248				5,802			7,432				314,359
	Construction real estate		106,158				1,139				97				2,867			4,103				110,261
	Indirect vehicle		206,126				1,588				498				421			2,507				208,633
	Home equity		291,737				3,557				1,888				8,004			13,449				305,186
	Other consumer		93,266				47				—				4			51				93,317
	Gross loans, excluding covered loans		5,230,351				28,960				10,391				47,378			86,729				5,317,080
	Covered loans		301,260				5,831				7,478				135,281			148,590				449,850
	Total loans (1)		$	5,531,611			$	34,791			$	17,869			$	182,659		$	235,319			$	5,766,930
	Nonperforming loan aging		$	69,836			$	3,171			$	3,718			$	40,261		$	47,150			$	116,986
	Non-covered loans related to FDIC transactions (2)		$	12,752			$	312			$	1,542			$	7,115		$	8,969			$	21,721
	(1)          Includes loans related to the InBank FDIC-assisted transaction completed by MB Financial Bank in 2009.
	(2)          Loans related to the InBank FDIC-assisted transaction completed by MB Financial Bank in 2009.
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 nonaccrual loans and loans past due ninety days or more and still accruing by class of loans as of December 31, 2013 and 2012 (in thousands):
			2013								2012
							Loans past due								Loans past due
			Nonaccrual				90 days or more				Nonaccrual				90 days or more
							and still accruing								and still accruing
	Commercial		$	17,781			$	—			$	23,886			$	229
	Commercial collateralized by assignment of lease payments		4,276				291				1,180				222
	Commercial real estate:
	Healthcare		3,064				—				3,238				—
	Industrial		15,265				155				19,179				147
	Multifamily		5,145				—				7,225				—
	Office		11,703				—				3,263				—
	Retail		2,969				—				17,019				—
	Other		19,991				—				9,437				—
	Residential real estate		13,009				—				10,943				—
	Construction real estate		475				—				1,028				—
	Indirect vehicle		1,459				—				1,494				—
	Home equity		10,969				—				17,486				1,000
	Other consumer		9				—				9				1
	Total		$	106,115			$	446			$	115,387			$	1,599
Risk category of loans by class of loans	'
	The following tables present the risk category of loans by class of loans based on the most recent analysis performed and the contractual aging as of December 31, 2013 and 2012 (in thousands):
			Pass				Special				Substandard				Doubtful			Total
							Mention
	31-Dec-13
	Commercial		$	1,193,114			$	26,637			$	61,000			$	626		$	1,281,377
	Commercial collateralized by assignment of lease payments		1,486,899				553				6,736				—			1,494,188
	Commercial real estate:
	Healthcare		189,705				21,186				2,774				3,064			216,729
	Industrial		345,236				5,328				29,280				—			379,844
	Multifamily		296,179				342				11,420				—			307,941
	Retail		316,420				10,660				17,520				—			344,600
	Office		151,393				2,682				3,927				—			158,002
	Other		217,188				349				23,047				—			240,584
	Construction real estate		139,847				540				866				—			141,253
	Total		$	4,335,981			$	68,277			$	156,570			$	3,690		$	4,564,518
	December 31, 2012
	Commercial		$	1,136,294			$	33,068			$	50,895			$	215		$	1,220,472
	Commercial collateralized by assignment of lease payments		1,292,241				3,322				7,457				—			1,303,020
	Commercial real estate:
	Healthcare		170,265				21,774				—				3,238			195,277
	Industrial		355,218				15,243				41,024				—			411,485
	Multifamily		318,991				25,297				14,063				—			358,351
	Retail		340,919				25,096				26,667				—			392,682
	Office		159,056				7,120				22,636				—			188,812
	Other		193,824				2,553				18,848				—			215,225
	Construction real estate		97,724				552				11,985				—			110,261
	Total		$	4,064,532			$	134,025			$	193,575			$	3,453		$	4,395,585
Recorded investment in loan classes based on payment activity	'
	and 2012 (in thousands):
			Performing				Non-performing				Total
	31-Dec-13
	Residential real estate		$	301,431			$	13,009			$	314,440
	Indirect vehicle		261,173				1,459				262,632
	Home equity		257,320				10,969				268,289
	Other consumer		66,943				9				66,952
	Total		$	886,867			$	25,446			$	912,313
	December 31, 2012
	Residential real estate		$	303,416			$	10,943			$	314,359
	Indirect vehicle		207,139				1,494				208,633
	Home equity		286,700				18,486				305,186
	Other consumer		93,307				10				93,317
	Total		$	890,562			$	30,933			$	921,495
Loans individually evaluated for impairment by class of loans	'
	The following tables present loans individually evaluated for impairment by class of loans as of December 31, 2013 and 2012 (in thousands):
			31-Dec-13
			Unpaid				Recorded				Partial				Allowance for			Average				Interest
			Principal				Investment				Charge-offs				Loan Losses			Recorded				Income
			Balance												Allocated			Investment				Recognized
	With no related allowance recorded:
	Commercial		$	8,903			$	8,903			$	—			$	—		$	8,259			$	—
	Commercial collateralized by assignment of lease payments		3,401				3,401				—				—			1,030				6
	Commercial real estate:
	Healthcare		—				—				—				—			2,698				—
	Industrial		7,560				7,560				—				—			8,900				—
	Multifamily		1,166				1,166				—				—			758				11
	Retail		4,466				4,466				—				—			3,628				—
	Office		559				527				32				—			922				—
	Other		2,963				2,963				—				—			4,380				—
	Residential real estate		4,234				4,234				—				—			3,260				—
	Construction real estate		—				—				—				—			—				—
	Indirect vehicle		—				—				—				—			—				—
	Home equity		577				577				—				—			797				—
	Other consumer		—				—				—				—			—				—
	With an allowance recorded:
	Commercial		8,923				8,919				4				4,284			13,476				4
	Commercial collateralized by assignment of lease payments		1,060				1,060				—				144			1,279				192
	Commercial real estate:
	Healthcare		3,186				3,064				122				382			8,189				—
	Industrial		7,707				7,705				2				3,038			3,699				—
	Multifamily		5,374				5,374				—				1,661			6,443				340
	Retail		14,169				12,428				1,741				1,511			12,885				280
	Office		2,442				2,442				—				791			4,045				—
	Other		20,367				17,029				3,338				796			12,868				20
	Residential real estate		13,496				12,710				786				3,119			12,966				245
	Construction real estate		475				475				—				227			1,603				—
	Indirect vehicle		173				123				50				57			86				—
	Home equity		23,840				23,395				445				1,358			24,283				772
	Other consumer		—				—				—				—			—				—
	Total		$	135,041			$	128,521			$	6,520			$	17,368		$	136,454			$	1,870
			December 31, 2012
			Unpaid				Recorded				Partial				Allowance for			Average				Interest
			Principal				Investment				Charge-offs				Loan Losses			Recorded				Income
			Balance												Allocated			Investment				Recognized
	With no related allowance recorded:
	Commercial		$	10,993			$	9,505			$	1,488			$	—		$	14,089			$	105
	Commercial collateralized by assignment of lease payments		390				390				—				—			278				9
	Commercial real estate:
	Healthcare		10,943				3,238				7,705				—			2,751				—
	Industrial		16,891				14,940				1,951				—			16,374				29
	Multifamily		800				800				—				—			1,340				14
	Retail		5,372				4,917				455				—			9,241				—
	Office		1,568				1,568				—				—			1,151				—
	Other		4,860				4,860				—				—			6,005				—
	Residential real estate		3,097				2,711				386				—			6,476				—
	Construction real estate		—				—				—				—			577				—
	Indirect vehicle		—				—				—				—			—				—
	Home equity		2,558				2,558				—				—			8,976				—
	Other consumer		—				—				—				—			182				—
	With an allowance recorded:
	Commercial		14,484				14,381				103				3,620			8,455				—
	Commercial collateralized by assignment of lease payments		885				885				—				188			1,130				95
	Commercial real estate:
	Healthcare		—				—				—				—			3,901				—
	Industrial		5,525				4,238				1,287				1,255			2,443				—
	Multifamily		8,233				7,249				984				2,284			5,847				180
	Retail		23,144				17,257				5,887				3,604			10,058				293
Office		1,706				1,695				11				522			1,904				—
Other		4,661				4,577				84				1,263			6,082				16
Residential real estate		10,565				10,565				—				2,858			3,417				227
Construction real estate		4,552				2,167				2,385				497			3,775				61
Indirect vehicle		—				—				—				—			—				—
Home equity		13,765				13,763				2				850			4,800				563
Other consumer		—				—				—				—			—				—
Total		$	144,992			$	122,264			$	22,728			$	16,941		$	119,252			$	1,592
Av
Schedule of loans that have been restructured classified as performing and non-performing	'
	The following table presents loans that have been restructured during the year ended December 31, 2013 (dollars in thousands):
			31-Dec-13
			Number of		Pre-Modification Recorded				Post-Modification Recorded				Charge-offs and
			Loans		Investment				Investment				Specific Reserves
	Performing:
	Commercial real estate:
	Multifamily		1		$	601			$	601			$	—
	Residential real estate		6		910				910				—
	Home equity		14		2,204				2,204				—
	Total		21		$	3,715			$	3,715			$	—
	Non-Performing:
	Commercial		2		$	1,251			$	1,251			$	673
	Commercial collateralized by assignment of lease payments		1		3,401				3,401				—
	Commercial real estate:
	Healthcare		1		3,164				3,164				496
	Industrial		4		2,570				2,570				1,425
	Multifamily		2		623				623				169
	Retail		3		862				862				235
	Other		1		84				84				23
	Residential real estate		9		1,803				1,682				121
	Indirect vehicle		26		171				129				42
	Home equity		26		3,430				3,430				—
	Total		75		$	17,359			$	17,196			$	3,184
	The following table presents loans that have been restructured during the year ended December 31, 2012 (dollars in thousands):
			December 31, 2012
			Number of			Pre-Modification Recorded				Post-Modification Recorded				Charge-offs and
			Loans			Investment				Investment				Specific Reserves
	Performing:
	Commercial real estate:
	Multifamily		2			$	262			$	262			$	—
	Retail		1			236				236				—
	Residential real estate		4			1,575				1,575				—
	Construction real estate		1			1,158				1,158				—
	Home equity		53			7,943				7,867				76
	Total		61			$	11,174			$	11,098			$	76
	Non-Performing:
	Commercial		4			$	3,305			$	3,305			$	73
	Commercial collateralized by assignment of lease payments		1			202				202				168
	Commercial real estate:
	Industrial		1			284				284				77
	Multifamily		2			333				333				220
	Retail		4			818				818				204
	Other		1			157				157				50
	Residential real estate		5			1,092				857				235
	Home equity		42			5,283				5,283				—
	Total		60			$	11,474			$	11,239			$	1,027
Troubled debt restructuring activity rollforward	'
	The following tables present the troubled debt restructurings activity during the year ended December 31, 2013 (dollars in thousands):
			Performing				Non-performing
	Beginning balance		$	21,256			$	28,418
	Additions		3,715				17,359
	Charge-offs		(71		)		(3,810		)
	Principal payments, net		(2,813		)		(8,901		)
	Removals		—				(565		)
	Transfer to other real estate owned		—				(206		)
	Transfer from non-performing/performing		8,603				1,260
	Transfer to non-performing/performing		(1,260		)		(8,603		)
	Ending balance		$	29,430			$	24,952
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, 2013 (dollars in thousands):
		December 31, 2013
		Extended				Extended				Extended				Extended
		Maturity,				Maturity, Delay				Maturity and				Maturity, Delay							Delay in
		Amortization				in Payments and				Delay in Payments				in Payments and							Payments or
		and Reduction				Reduction of				or Reduction of				Reduction of			Extended				Reduction of
		of Interest Rate				Interest Rate				Interest Rate				Amount			Maturity				Interest Rate			Total
	Commercial	$	42			$	—			$	1,209			$	—		$	—			$	—		$	1,251
	Commercial collateralized by assignment of lease payments	—				—				3,401				—			—				—			3,401
	Commercial real estate:
	Healthcare	—				—				—				3,164			—				—			3,164
	Industrial	—				—				—				—			2,570				—			2,570
	Multifamily	187				—				—				—			601				436			1,224
	Retail	256				205				401				—			—				—			862
	Office	—				—				—				—			—				—			—
	Other	84				—				—				—			—				—			84
	Residential real estate	1,917				—				—				—			178				618			2,713
	Construction real estate	—				—				—				—			—				—			—
	Indirect vehicle	—				—				—				—			44				127			171
	Home equity	2,875				—				708				—			440				1,611			5,634
	Other consumer	—				—				—				—			—				—			—
	Total	$	5,361			$	205			$	5,719			$	3,164		$	3,833			$	2,792		$	21,074
Activity in the allowance for loan losses	'
	Activity in the allowance for loan losses was as follows (in thousands):
			Year Ended December 31,
			2013				2012				2011
	Balance at beginning of year		$	128,279			$	135,975			$	192,217
	Provision for credit losses		(5,804		)		(8,900		)		120,750
	Charge-offs:
	Commercial		3,706				2,408				17,571
	Commercial collateralized by assignment of lease payments		—				1,721				1,466
	Commercial real estate		7,517				11,377				96,633
	Residential real estate		2,796				2,944				12,643
	Construction real estate		980				4,007				52,917
	Indirect vehicle		2,911				2,259				2,836
	Home equity		3,692				4,551				11,066
	Other consumer		2,073				1,349				1,648
	Total charge-offs		23,675				30,616				196,780
	Recoveries:
	Commercial		3,156				3,475				5,370
	Commercial collateralized by assignment of lease payments		1,131				6,720				225
	Commercial real estate		6,025				16,987				3,332
	Residential real estate		479				501				49
	Construction real estate		1,616				2,019				8,590
	Indirect vehicle		1,411				1,096				1,399
	Home equity		594				671				224
	Other consumer		250				351				599
	Total recoveries		14,662				31,820				19,788
	Net charge-offs (recoveries)		9,013				(1,204		)		176,992
	Allowance for credit losses		113,462				128,279				135,975
	Allowance for unfunded credit commitments		(1,716		)		(4,075		)		(9,177		)
	Balance at December 31,		$	111,746			$	124,204			$	126,798
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, 2013 and 2012 (in thousands):
			Commercial				Commercial				Commercial				Residential			Construction				Indirect			Home		Other Consumer		Unfunded			Total
							collateralized  by				real estate				real estate			real estate				vehicle			equity				Commitments
							assignment of
							lease payments
	December 31, 2013
	Allowance for credit losses:
	Beginning balance		$	24,943			$	7,755			$	61,056			$	6,941		$	11,222			$	1,324		$	9,401	$	1,562	$	4,075		$	128,279
	Transfer to (from) allowance for unfunded credit commitments		—				—				—				—			500				—			—		—		(500		)	—
	Charge-offs		3,706				—				7,517				2,796			980				2,911			3,692		2,073		—			23,675
	Recoveries		3,156				1,131				6,025				479			1,616				1,411			594		250		—			14,662
	Provision		(932		)		273				(7,936		)		4,248			(5,502		)		1,838			2,175		1,891		(1,859		)	(5,804		)
	Ending balance		$	23,461			$	9,159			$	51,628			$	8,872		$	6,856			$	1,662		$	8,478	$	1,630	$	1,716		$	113,462
	Ending allowance balance attributable to loans:
	Individually evaluated for impairment		$	4,284			$	144			$	8,179			$	3,119		$	227			$	57		$	1,358	$	—	$	689		$	18,057
	Collectively evaluated for impairment		18,693				9,015				41,763				5,753			6,567				1,605			7,120		1,630		1,027			93,173
	Acquired and accounted for under ASC 310-30 (1)		484				—				1,686				—			62				—			—		—		—			2,232
	Total ending allowance balance		$	23,461			$	9,159			$	51,628			$	8,872		$	6,856			$	1,662		$	8,478	$	1,630	$	1,716		$	113,462
	Loans:
	Individually evaluated for impairment		$	17,822			$	4,461			$	64,724			$	16,944		$	475			$	123		$	23,972	$	—	$	—		$	128,521
	Collectively evaluated for impairment		1,246,523				1,489,727				1,582,976				293,883			140,778				262,509			244,317		66,952		—			5,327,665
	Acquired and accounted for under ASC 310-30 (1)		35,673				—				140,504				5,448			48,313				—			107		26,320		—			256,365
	Total ending loans balance		$	1,300,018			$	1,494,188			$	1,788,204			$	316,275		$	189,566			$	262,632		$	268,396	$	93,272	$	—		$	5,712,551
	December 31, 2012
	Allowance for credit losses:
	Beginning balance		$	21,106			$	7,561			$	68,695			$	3,935		$	15,639			$	1,834		$	7,333	$	695	$	9,177		$	135,975
	Transfer to (from) allowance for unfunded credit commitments		—				—				—				—			1,132				—			—		—		(1,132		)	—
	Charge-offs		2,408				1,721				11,377				2,944			4,007				2,259			4,551		1,349		—			30,616
	Recoveries		3,475				6,720				16,987				501			2,019				1,096			671		351		—			31,820
	Provision		2,770				(4,805		)		(13,249		)		5,449			(3,561		)		653			5,948		1,865		(3,970		)	(8,900		)
	Ending balance		$	24,943			$	7,755			$	61,056			$	6,941		$	11,222			$	1,324		$	9,401	$	1,562	$	4,075		$	128,279
	Ending allowance balance attributable to loans:
	Individually evaluated for impairment		$	3,620			$	188			$	8,928			$	2,858		$	497			$	—		$	850	$	—	$	3,499		$	20,440
	Collectively evaluated for impairment		18,878				7,567				50,120				4,083			10,662				1,324			8,551		1,562		576			103,323
	Acquired and accounted for under ASC 310-30 (1)		2,445				—				2,008				—			63				—			—		—		—			4,516
	Total ending allowance balance		$	24,943			$	7,755			$	61,056			$	6,941		$	11,222			$	1,324		$	9,401	$	1,562	$	4,075		$	128,279
	Loans:
	Individually evaluated for impairment		$	23,886			$	1,275			$	65,339			$	13,276		$	2,167			$	—		$	16,321	$	—	$	—		$	122,264
	Collectively evaluated for impairment		1,178,804				1,301,745				1,696,493				297,144			108,094				208,633			288,865		93,317		—			5,173,095
	Acquired and accounted for under ASC 310-30 (1)		65,658				—				247,390				6,528			118,360				—			465		33,170		—			471,571
	Total ending loans balance		$	1,268,348			$	1,303,020			$	2,009,222			$	316,948		$	228,621			$	208,633		$	305,651	$	126,487	$	—		$	5,766,930
	(1)  Loans acquired in FDIC-assisted transactions and accounted for under ASC Subtopic 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 in FDIC-assisted transactions and accounted for under ASC 310-30 were as follows for the years ended December 31, 2013 and 2012 (in thousands):
			Year Ended December 31,
			2013				2012
	Balance at beginning of period		$	5,685			$	18,703
	Accretion		(4,456		)		(13,535		)
	Other		1,108				517
	Balance at end of period		$	2,337			$	5,685
Purchased loans disclosures	'
	The carrying amount of covered loans and other purchased non-covered loans at December 31, 2013 consisted of purchased credit-impaired loans and non-credit-impaired loans as shown in the following table (in thousands):
	31-Dec-13		Purchased				Purchased  Non-Impaired				Total
			Impaired				Loans
			Loans
	Covered loans:
	Commercial related (1)		$	9,445			$	5,629			$	15,074
	Commercial		803				2,764				3,567
	Commercial real estate		51,762				88,742				140,504
	Construction real estate		41,928				6,385				48,313
	Other		2,529				25,733				28,262
	Total covered loans		$	106,467			$	129,253			$	235,720
	Estimated receivable amount from the FDIC under the loss-share agreement (2)		$	570			$	9,974			$	10,544
	Non covered loans:
	Commercial related (3)		$	4,726			$	12,306			$	17,032
	Other		89				3,524				3,613
	Total non-covered loans		$	4,815			$	15,830			$	20,645
	-1	Covered commercial related loans include commercial, commercial real estate and construction real estate loans acquired in connection with the Heritage and Benchmark FDIC-assisted transactions.
	-2	Estimated reimbursable amounts from the FDIC under the loss-share agreement exclude $1.1 million in reimbursable amounts related to covered other real estate owned.
	-3	Non covered commercial related loans include commercial, commercial real estate and construction real estate for InBank.

Lease_Investments_Tables

Lease Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Lease Investments	'
Schedule of lease investments by categories	'
	Lease investments by categories follow (in thousands):
		December 31,
		2013			2012
	Direct finance leases:
	Minimum lease payments	$	155,945		$	96,834
	Estimated unguaranteed residual values	31,272			32,013
	Less: unearned income	(14,473		)	(6,995		)
	Direct finance leases (1)	$	172,744		$	121,852
	Leveraged leases:
	Minimum lease payments	$	24,320		$	28,831
	Estimated unguaranteed residual values	2,508			2,714
	Less: unearned income	(1,644		)	(2,376		)
	Less: related non-recourse debt	(23,243		)	(27,319		)
	Leveraged leases (1)	$	1,941		$	1,850
	Operating leases:
	Equipment, at cost	$	218,473		$	222,083
	Less accumulated depreciation	(87,384		)	(92,260		)
	Lease investments, net	$	131,089		$	129,823
	(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			Leveraged			Operating
		Finance
	Year	Leases			Leases			Leases			Total
	2014	$	62,310		$	13,622		$	34,839		$	110,771
	2015	45,899			7,395			23,263			76,557
	2016	26,814			2,482			13,981			43,277
	2017	13,247			642			5,232			19,121
	2018	5,838			179			2,011			8,028
	Thereafter	1,837			—			421			2,258
		$	155,945		$	24,320		$	79,747		$	260,012
Income from lease investments	'
	Income from lease financing, net was composed of (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Rental income	$	62,629		$	49,473		$	54,859
	Equipment maintenance contracts revenue, net of cost of sales	11,071			14,129			7,713
	Vendor promotional income	7,587			4,051			3,191
	Other lease related revenue	1,796			167			408
	Gain on sale of lease payments and leased equipment, net of residual write downs	12,002			4,708			3,158
	Income on lease investments, gross	95,085			72,528			69,329
	Less:
	Depreciation on operating leases	(33,842		)	(36,146		)	(42,390		)
	Lease financing, net	$	61,243		$	36,382		$	26,939
Schedule of residual values for leases by category in the year the initial lease term ends	'
	At December 31, 2013, 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			Leveraged			Operating
	December 31,	Leases			Leases			Leases			Total
	2014	$	12,417		$	802		$	13,239		$	26,458
	2015	7,427			974			8,310			16,711
	2016	6,203			609			9,793			16,605
	2017	2,975			105			6,680			9,760
	2018	1,420			18			3,533			4,971
	Thereafter	830			—			1,433			2,263
		$	31,272		$	2,508		$	42,988		$	76,768

Premises_and_Equipment_Tables

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property, Plant and Equipment [Abstract]	'
Schedule of premises and equipment	'
	Premises and equipment consisted of (in thousands):
		December 31,
		2013			2012
	Land and land improvements	$	67,389		$	69,832
	Buildings	98,675			97,365
	Furniture and equipment	97,766			88,425
	Buildings and leasehold improvements	55,639			49,813
		319,469			305,435
	Accumulated depreciation	(98,404		)	(83,902		)
	Premises and equipment, net	$	221,065		$	221,533

Goodwill_and_Intangibles_Table

Goodwill and Intangibles (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
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, 2013 and 2012 (in thousands):
			December 31,
			2013			2012
	Balance at beginning of period		$	29,512		$	29,494
	Amortization expense		(6,084		)	(5,010		)
	Other intangibles from business combinations		—			5,028
	Balance at end of period		$	23,428		$	29,512
	Gross carrying amount		$	60,292		$	61,429
	Accumulated amortization		(36,864		)	(31,917		)
	Net book value		$	23,428		$	29,512
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
	2014	$	4,748
	2015	4,030
	2016	3,418
	2017	3,071
	2018	2,812
	Thereafter	5,349
		$	23,428

Deposits_Tables

Deposits (Tables)	12 Months Ended
	Dec. 31, 2013
Deposits [Abstract]	'
Schedule of composition of deposits	'
	The composition of deposits was as follows (in thousands):
			December 31,
			2013		2012
	Demand deposit accounts, noninterest bearing		$	2,375,863	$	2,164,547
	NOW and money market accounts		2,682,419		2,747,273
	Savings accounts		855,394		811,333
	Certificates of deposit, $100,000 or more		827,413		1,020,033
	Other certificates of deposit		640,170		799,511
	Total		$	7,381,259	$	7,542,697
Schedule of maturities of time certificates	'
	At December 31, 2013, the scheduled maturities of certificates of deposit were as follows (in thousands):
	2014	$	1,064,248
	2015	205,921
	2016	64,423
	2017	49,420
	2018	18,739
	Thereafter	64,832
		$	1,467,583

ShortTerm_Borrowings_Tables

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2013
Short-term Debt [Abstract]	'
Summary of short-term borrowings	'
	Short-term borrowings were as follows as of December 31, 2013 and 2012 (dollars in thousands):
		December 31,
		2013				2012
		Weighted				Weighted
		Average				Average
		Cost		Amount		Cost		Amount
	Customer repurchase agreements	0.2	%	$	193,389	0.23	%	$	208,242
	Federal Home Loan Bank advances	0.17	%	300,000		3.58	%	12,360
		0.18	%	$	493,389	0.42	%	$	220,602

Longterm_Borrowings_Tables

Long-term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2013
Long-term Debt, Unclassified [Abstract]	'
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,
	2014	$	8,974
	2015	5,743
	2016	42,915
	2017	751
	2018	180
	Thereafter	3,596
		$	62,159

Junior_Subordinated_Notes_Issu1

Junior Subordinated Notes Issued to Capital Trusts (Tables)	12 Months Ended
	Dec. 31, 2013
JUNIOR SUBORDINATED NOTES ISSUED TO CAPITAL TRUSTS	'
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, 2013 (in thousands):
			Coal City		MB Financial		MB Financial		MB Financial
			Capital Trust I		Capital Trust II		Capital Trust III		Capital Trust IV
	Junior Subordinated Notes:
	Principal balance		$	25,774	$	36,083	$	10,310	$	20,619
	Annual interest rate		3-mo LIBOR + 1.80%		3-mo LIBOR + 1.40%		3-mo LIBOR + 1.50%		3-mo LIBOR + 1.52%
	Stated maturity date		September 1, 2028		September 15, 2035		September 23, 2036		September 15, 2036
	Call date		September 1, 2008		December 15, 2010		September 23, 2011		September 15, 2011
	Trust Preferred Securities:
	Face Value		$	25,000	$	35,000	$	10,000	$	20,000
	Annual distribution rate		3-mo LIBOR + 1.80%		3-mo LIBOR + 1.40%		3-mo LIBOR + 1.50%		3-mo LIBOR + 1.52%
	Issuance date		July 1998		August 2005		July 2006		August 2006
	Distribution dates (1)		Quarterly		Quarterly		Quarterly		Quarterly
			MB Financial		MB Financial		FOBB
			Capital Trust V		Capital Trust VI		Statutory Trust III (2)
	Junior Subordinated Notes:
	Principal balance		$	30,928	$	23,196	$	5,155
	Annual interest rate		3-mo LIBOR + 1.30%		3-mo LIBOR + 1.30%		3-mo LIBOR + 2.80%
	Stated maturity date		December 15, 2037		October 30, 2037		January 23, 2034
	Call date		December 15, 2012		October 30, 2012		January 23, 2009
	Trust Preferred Securities:
	Face Value		$	30,000	$	22,500	$	5,000
	Annual distribution rate		3-mo LIBOR + 1.30%		3-mo LIBOR + 1.30%		3-mo LIBOR + 2.80%
	Issuance date		September 2007		October 2007		December 2003
	Distribution dates (1)		Quarterly		Quarterly		Quarterly
	-1	All distributions are cumulative and paid in cash.
	-2	FOBB Statutory Trust III was established by First Oak Brook Bancshares, Inc. (“FOBB”) prior to the Company's acquisition of FOBB, and the junior subordinated note issued by FOBB to FOBB Statutory Trust III was assumed by the Company upon completion of the acquisition.

Lease_Commitments_and_Rental_E1

Lease Commitments and Rental Expense (Tables)	12 Months Ended
	Dec. 31, 2013
Lease Commitments and Rental Expense	'
Future minimum annual rental commitments for noncancelable leases and subleases	'
	The Company leases office space for certain branch offices.  At December 31, 2013, the future minimum annual rental commitments for these noncancelable leases and subleases of such space were as follows (in thousands):
		Gross		Sublease		Net
	Years ending December 31,	Rents		Rents		Rents
	2014	$	5,408	$	926	$	4,482
	2015	4,801		697		4,104
	2016	3,810		444		3,366
	2017	2,929		422		2,507
	2018	2,202		414		1,788
	Thereafter	16,580		1,005		15,575
		$	35,730	$	3,908	$	31,822

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Taxes	'
Schedule of deferred tax assets and liabilities	'
	The deferred taxes consist of (in thousands):
		December 31,
		2013			2012
	Deferred tax asset:
	Allowance for credit losses	$	44,418		$	50,336
	Federal net operating loss carryforwards	—			1,926
	State net operating loss carryforwards	24,354			23,677
	Other real estate owned	7,878			22,153
	Stock options and restricted stock	5,816			5,808
	Loans	6,833			8,628
	Deferred compensation	8,423			6,129
	Tax credit carryforwards	13,233			15,491
	Bonus accrual	4,739			4,438
	Merger and non-compete accrual	623			865
	Other items	1,222			1,343
	Total deferred tax asset	117,539			140,794
	Valuation allowance	—			—
	Total deferred tax asset, net of valuation allowance	117,539			140,794
	Deferred tax liability:
	Premises and equipment	(118,000		)	(116,780		)
	Deferred income from FDIC-assisted transactions	(48,272		)	(50,565		)
	Investment securities	(5,030		)	(5,573		)
	FHLB stock dividends	(2,441		)	(2,774		)
	Core deposit intangible	(2,918		)	(2,669		)
	Other items	(3,799		)	(3,673		)
	Total deferred tax liability	(180,460		)	(182,034		)
	Net deferred tax liability	(62,921		)	(41,240		)
	Net unrealized holding gain on investment securities available for sale	(5,354		)	(23,431		)
	Net deferred tax liability	$	(68,275	)	$	(64,671	)
Schedule of income taxes attributable to continuing operations	'
	Income taxes attributable to continuing operations consist of (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Current expense (benefit):
	Federal	$	12,234		$	15,075		$	713
	State	5,576			6,225			(611		)
	Foreign	—			—			—
		17,810			21,300			102
	Deferred expense	21,681			15,177			5,166
		$	39,491		$	36,477		$	5,268
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 35% and the effective tax rate on income from continuing operations follows (in thousands):
		Years Ended December 31,
		2013			2012			2011
	Federal income tax expense at expected statutory rate	$	48,281		$	44,398		$	15,398
	Increase (decrease) due to:
	Tax exempt income, net	(14,200		)	(12,539		)	(8,162		)
	State tax benefit resulting from change in tax rate	—			—			(2,100		)
	State tax expense net of federal impact	6,508			5,014			1,703
	Nonincludable increase in cash surrender value of life insurance	(1,111		)	(1,177		)	(1,529		)
	Nondeductible merger expense	591			—			—
	Adjustment of tax contingency reserves	(24		)	14			35
	Other items, net	(554		)	767			(77		)
	Income tax expense	$	39,491		$	36,477		$	5,268
Schedule of reconciliation of the change in unrecognized tax benefits	'
	A reconciliation of the change in unrecognized tax benefits from January 1, 2013 to December 31, 2013 is as follows (in thousands):
		Unrecognized Tax Benefit			Interest on unrecognized			Total Unrecognized Tax
		Without Interest			Tax Benefit			Benefit Including Interest
	Balance at January 1, 2013	$	95		$	9		$	104
	Increases for tax positions of prior years	15			5			20
	Benefits recognized	(37		)	(7		)	(44		)
	Balance at December 31, 2013	$	73		$	7		$	80

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Schedule of outstanding financial instruments, contractual amounts of off-balance sheet credit risk	'
	At December 31, 2013 and 2012, the following financial instruments were outstanding, the contractual amounts of which represent off-balance sheet credit risk (in thousands):
		Contractual Amount
		2013		2012
	Commitments to extend credit:
	Home equity lines	$	208,581	$	239,771
	Other commitments	1,214,391		911,166
	Letters of credit:
	Standby	69,556		66,247
	Commercial	708		465

Regulatory_Matters_Tables

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2013
Regulatory Matters	'
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 (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, 2013
	Total capital (to risk-weighted assets):
	Consolidated	$	1,106,541	16.53	%	$	535,430	8	%	N/A		N/A
	MB Financial Bank	974,189		14.59		534,004		8		$	667,505	10	%
	Tier 1 capital (to risk-weighted assets):
	Consolidated	1,022,512		15.28	%	267,715		4	%	N/A		N/A
	MB Financial Bank	890,380		13.34		267,002		4		400,503		6	%
	Tier 1 capital (to average assets):
	Consolidated	1,022,512		11.22	%	364,587		4	%	N/A		N/A
	MB Financial Bank	890,380		9.79		363,904		4		454,880		5	%
	As of December 31, 2012
	Total capital (to risk-weighted assets):
	Consolidated	$	1,059,357	16.62	%	$	509,885	8	%	N/A		N/A
	MB Financial Bank	983,817		15.49		508,016		8		$	635,021	10	%
	Tier 1 capital (to risk-weighted assets):
	Consolidated	939,087		14.73	%	254,942		4	%	N/A		N/A
	MB Financial Bank	863,836		13.6		254,008		4		381,012		6	%
	Tier 1 capital (to average assets):
	Consolidated	939,087		10.5	%	357,906		4	%	N/A		N/A
	MB Financial Bank	863,836		9.68		356,984		4		446,230		5	%
	N/A — not applicable

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
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, 2013 and 2012, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value (in thousands):
			Total				Quoted Prices in				Significant Other				Significant
							Active Markets for				Observable Inputs				Unobservable Inputs
							Identical Assets				(Level 2)				(Level 3)
							(Level 1)
	2013
	Financial assets
	Securities available for sale:
	U.S. Government sponsored agencies and enterprises		$	52,068			$	—			$	52,068			$	—
	States and political subdivisions		19,143				—				19,143				—
	Residential mortgage-backed securities		701,233				—				700,542				691
	Commercial mortgage-backed securities		52,941				—				52,941				—
	Corporate bonds		283,070				—				277,905				5,165
	Equity securities		10,457				10,457				—				—
	Loans held for sale		629				—				629				—
	Assets held in trust for deferred compensation		10,679				10,679				—				—
	Derivative financial instruments		18,645				—				18,645				—
	Financial liabilities
	Other liabilities (1)		10,569				10,569				—				—
	Derivative financial instruments		18,632				—				18,632				—
	2012
	Financial assets
	Securities available for sale:
	U.S. Government sponsored agencies and enterprises		$	41,315			$	—			$	41,315			$	—
	States and political subdivisions		725,019				—				725,019				—
	Residential mortgage-backed securities		939,202				—				938,354				848
	Commercial mortgage-backed securities		54,126				—				54,126				—
	Corporate bonds		96,674				—				91,451				5,223
	Equity securities		11,835				11,835				—				—
	Loans held for sale		7,492				—				7,492				—
	Assets held in trust for deferred compensation		7,746				7,746				—				—
	Derivative financial instruments		29,096				—				29,096				—
	Financial liabilities
	Other liabilities (1)		7,746				7,746				—				—
	Derivative financial instruments		29,055				—				29,055				—
	(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 table presents additional information about the unobservable inputs used in the fair value measurement of 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	Unobservable
		December 31, 2013			Technique	Input	Range
	Impaired loans	$	77,497		Appraisal of collateral	Appraisal adjustments - sales costs	5% - 10%
	Foreclosed assets	44,601			Appraisal of collateral	Appraisal adjustments - sales costs	5% - 10%
	The following table presents 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			Valuation	Unobservable
		December 31, 2013			Technique	Input	Range
	Residential mortgage-backed securities	$	691		Discounted cash flows	Constant pre-payment rates
						(CPR) assumption	1% - 3% CPR
	Corporate bonds	5,165			Discounted cash flows	Credit assumption	20% Loss
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
			2013				2012
	Balance, beginning of period		$	6,071			$	6,992
	Other comprehensive income		(44		)		81
	Principal payments		(157		)		(885		)
	Impairment charge		(14		)		(117		)
	Balance, ending of period		$	5,856			$	6,071
Assets measured at fair value on a nonrecurring basis	'
	Assets measured at fair value on a nonrecurring basis as of December 31, 2013 and 2012 are included in the table below (in thousands):
			Total				Quoted Prices in Active				Significant Other				Significant
							Markets for Identical				Observable Inputs				Unobservable Inputs
							Assets (Level 1)				(Level 2)				(Level 3)
	2013
	Financial assets:
	Impaired loans		$	77,497			$	—			$	—			$	77,497
	Non-financial assets:
	Foreclosed assets		44,601				—				—				44,601
	2012
	Financial assets:
	Impaired loans		$	62,258			$	—			$	—			$	62,258
	Non-financial assets:
	Foreclosed assets		60,228				—				—				60,228
	Long-lived assets		2,314				—				—				2,314
Estimated fair values of financial instruments	'
	The estimated fair values of financial instruments are as follows (in thousands):
			December 31, 2013
			Carrying Amount				Estimated Fair Value			Quoted Prices in Active			Significant Other			Significant
										Markets for Identical			Observable Inputs			Unobservable Inputs
										Assets (Level 1)			(Level 2)			(Level 3)
	Financial Assets:
	Cash and due from banks		$	205,193			$	205,193		$	205,193		$	—		$	—
	Interest bearing deposits with banks		268,266				268,266			268,266			—			—
	Federal funds sold		42,950				42,950			42,950			—			—
	Investment securities available for sale		1,118,912				1,118,912			10,457			1,102,599			5,856
	Investment securities held to maturity		1,182,533				1,198,929			—			1,198,929			—
	Non-marketable securities - FHLB and FRB stock		51,417				51,417			—			—			51,417
	Loans held for sale		629				629			—			629			—
	Loans, net		5,600,805				5,583,759			—			—			5,583,759
	Accrued interest receivable		36,593				36,593			36,593			—			—
	Derivative financial instruments		18,645				18,645			—			18,645			—
	Financial Liabilities:
	Non-interest bearing deposits		$	2,375,863			$	2,375,863		$	2,375,863		$	—		$	—
	Interest bearing deposits		5,005,396				5,012,928			—			—			5,012,928
	Short-term borrowings		493,389				493,384			—			—			493,384
	Long-term borrowings		62,159				66,301			—			—			66,301
	Junior subordinated notes issued to capital trusts		152,065				101,247			—			—			101,247
	Accrued interest payable		2,042				2,042			2,042			—			—
	Derivative financial instruments		18,632				18,632			—			18,632			—
			December 31, 2012
			Carrying Amount				Estimated Fair Value			Quoted Prices in Active			Significant Other			Significant
										Markets for Identical			Observable Inputs			Unobservable Inputs
										Assets (Level 1)			(Level 2)			(Level 3)
	Financial Assets:
	Cash and due from banks		$	176,010			$	176,010		$	176,010		$	—		$	—
	Interest bearing deposits with banks		111,533				111,533			111,533			—			—
	Investment securities available for sale		1,868,171				1,868,171			11,835			1,850,265			6,071
	Investment securities held to maturity		493,421				535,681			—			535,681			—
	Non-marketable securities - FHLB and FRB stock		55,385				55,385			—			—			55,385
	Loans held for sale		7,492				7,492			—			7,492			—
	Loans, net		5,642,726				5,659,598			—			—			5,659,598
	Accrued interest receivable		36,040				36,040			36,040			—			—
	Derivative financial instruments		29,096				29,096			—			29,096			—
	Financial Liabilities:
	Non-interest bearing deposits		$	2,164,547			$	2,164,547		$	2,164,547		$	—		$	—
	Interest bearing deposits		5,378,150				5,399,709			—			—			5,399,709
	Short-term borrowings		220,602				220,683			—			—			220,683
	Long-term borrowings		116,050				117,809			—			—			117,809
	Junior subordinated notes issued to capital trusts		152,065				104,009			—			—			104,009
	Accrued interest payable		2,828				2,828			2,828			—			—
	Derivative financial instruments		29,055				29,055			—			29,055			—

Stock_Incentive_Plans_Tables

Stock Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Summary of the impact of share-based payment plans in the financial statements	'
	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,
		2013				2012				2011
	Total cost of share-based payment plans during the year	$	5,456			$	4,806			$	4,836
	Amount of related income tax benefit recognized in income	$	2,159			$	1,918			$	1,972
Additional information related to options outstanding	'
	The following table summarizes stock options outstanding for the year ended December 31, 2013:
		Number of			Weighted				Weighted		Aggregate
		Options			Average				Average		Intrinsic
					Exercise				Remaining		Value
					Price				Contractual		(in thousands)
									Term
									(in years)
	Options outstanding as of December 31, 2012	2,739,753			$	27.34
	Granted	225,269			27.34
	Exercised	(381,417	)		25.11
	Expired or cancelled	(118,690	)		31.13
	Forfeited	(21,163	)		20.04
	Options outstanding as of December 31, 2013	2,443,752			$	27.57			4.71		$	14,980
	Options exercisable as of December 31, 2013	1,766,966			$	29.93			3.43		$	7,761
Assumptions used for options granted	'
	The following assumptions were used for options granted during the years ended December 31, 2013, 2012, and 2011:
		For the Years Ended December 31,
		2013				2012				2011
	Risk-free interest rate	1.92		%		1.02		%		1.95		%
	Expected volatility of Company’s stock	25.18		%		27.17		%		43.72		%
	Expected dividend yield	1.73		%		2		%		1.48		%
	Expected life of options (years)	5.6				5.7				5.8
	Weighted average fair value per option of options granted during the year	$	5.88			$	4.23			$	7.57
Summary of changes in restricted shares	'
	The following is a summary of changes in restricted shares and units for the year ended December 31, 2013:
		Number of			Weighted
		Shares			Average
					Grant Date
					Fair Value
	Shares and Units Outstanding at December 31, 2012	634,211			$	18.82
	Granted	272,152			26.92
	Vested	(203,495	)		16.78
	Forfeited	(17,149	)		20.86
	Shares and Units Outstanding at December 31, 2013	685,719			$	22.59

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
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, 2013 and 2012 (in thousands):
		Asset Derivatives											Liability Derivatives
		December 31, 2013						December 31, 2012					December 31, 2013					December 31, 2012
		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)	$	—		$	—		$	—		$	—	$	238	$	(23	)	$	3,707		$	(94	)
	Stand-alone derivative instruments: (2)
	Interest rate swap contracts	550,883			17,298			460,956			27,740		551,798		(17,350		)	462,012			(27,832		)
	Interest rate options contracts	83,907			323			70,346			157		84,953		(323		)	70,346			(157		)
	Foreign exchange contracts	31,361			1,006			20,033			1,062		47,760		(935		)	19,337			(961		)
	Mortgage banking derivatives	1,783			18			11,400			137		250		(1		)	4,000			(11		)
	Total non-hedging derivative instruments	667,934			18,645			562,735			29,096		684,761		(18,609		)	555,695			(28,961		)
	Total	$	667,934		$	18,645		$	562,735		$	29,096	$	684,999	$	(18,632	)	$	559,402		$	(29,055	)
	(1) Hedged 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 the other income in the consolidated statements of operations related to derivative financial instruments were as follows (in thousands):
		Years Ended
		December 31,
		2013			2012			2011
	Derivative instruments designated as hedges of fair value:
	Interest rate swap contracts	$	9		$	(15	)	$	(166	)
	Stand-alone derivative instruments:
	Interest rate swap contracts	40			30			163
	Interest rate options contracts	—			—			—
	Foreign exchange contracts	(30		)	67			8
	Mortgage banking derivatives	(109		)	96			31
	Total non-hedging derivative instruments	(99		)	193			202
	Total	$	(90	)	$	178		$	36
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, 2013 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	$	5,792		$	—		$	5,792		$	11,904	$	—	$	11,904
	Foreign currency forward contracts	80			—			80			848		—		848
	Mortgage banking derivatives	3			—			3			1		—		1
	Total derivatives	5,875			—			5,875			12,753		—		12,753
	Repurchase agreements	—			—			—			193,389		—		193,389
	Total	$	5,875		$	—		$	5,875		$	206,142	$	—	$	206,142
		Financial Assets											Financial Liabilities
		Net Amount Recognized			Financial Instruments			Collateral			Net Amount		Net Amount Recognized		Financial Instruments			Collateral			Net Amount
	Derivatives:
	Counterparty A	$	883		$	(883	)	$	—		$	—	$	10,669	$	(883	)	$	(9,786	)	$	—
	Counterparty B	1,836			(412		)	—			1,424		412		(412		)	—			—
	Counterparty C	2,380			(1,612		)	—			768		1,612		(1,612		)	—			—
	Other counterparties	776			(5		)	—			771		60		(5		)	—			55
	Total derivatives	5,875			(2,912		)	—			2,963		12,753		(2,912		)	(9,786		)	55
	Repurchase agreements	—			—			—			—		193,389		—			(193,389		)	—
	Total	$	5,875		$	(2,912	)	$	—		$	2,963	$	206,142	$	(2,912	)	$	(203,175	)	$	55
		Financial Assets											Financial Liabilities
		Net Amount Recognized			Financial Instruments			Collateral			Net Amount		Net Amount Recognized		Financial Instruments			Collateral			Net Amount
	Derivatives:
	Counterparty A	$	68		$	(68	)	$	—		$	—	$	25,497	$	(68	)	$	(25,429	)	$	—
	Counterparty B	84			(84		)	—			—		633		(84		)	(549		)	—
	Counterparty C	36			(36		)	—			—		2,305		(36		)	(2,269		)	—
	Other counterparties	48			(42		)	—			6		395		(42		)	(298		)	55
	Total derivatives	236			(230		)	—			6		28,830		(230		)	(28,545		)	55
	Repurchase agreements	—			—			—			—		208,242		—			(208,242		)	—
	Total	$	236		$	(230	)	$	—		$	6	$	237,072	$	(230	)	$	(236,787	)	$	55
	Information about the Company's financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 2012 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	$	192		$	—		$	192		$	27,890	$	—	$	27,890
	Foreign currency forward contracts	43			—			43			929		—		929
	Mortgage banking derivatives	1			—			1			11		—		11
	Total derivatives	236			—			236			28,830		—		28,830
	Repurchase agreements	—			—			—			208,242		—		208,242
	Total	$	236		$	—		$	236		$	237,072	$	—	$	237,072

Operating_Segments_Tables

Operating Segments (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Schedule of segment reporting information, by segment	'
	The following table presents summary financial information for the reportable segments (in thousands):
		Banking			Leasing			Consolidated
	Year ended December 31,
	2013
	Net interest income	$	267,131		$	5,205		$	272,336
	Provision for credit losses	(6,167		)	363			(5,804		)
	Non-interest income	94,600			59,794			154,394
	Non-interest expense	259,753			34,835			294,588
	Income tax expense	28,201			11,290			39,491
	Net income	$	79,944		$	18,511		$	98,455
	Total assets	$	9,225,610		$	415,817		$	9,641,427
	Year ended December 31,
	2012
	Net interest income	$	290,881		$	1,907		$	292,788
	Provision for credit losses	(9,035		)	135			(8,900		)
	Non-interest income	95,449			33,744			129,193
	Non-interest expense	284,452			19,578			304,030
	Income tax expense	30,780			5,697			36,477
	Net income	$	80,133		$	10,241		$	90,374
	Total assets	$	9,203,837		$	367,968		$	9,571,805
	Year ended December 31,
	2011
	Net interest income	$	324,356		$	917		$	325,273
	Provision for credit losses	120,808			(58		)	120,750
	Non-interest income	95,936			26,783			122,719
	Non-interest expense	267,455			15,791			283,246
	Income tax expense	1,182			4,086			5,268
	Net income	$	30,847		$	7,881		$	38,728
	Total assets	$	9,623,039		$	210,033		$	9,833,072

Condensed_Parent_Company_Finan1

Condensed Parent Company Financial Information (Tables)	12 Months Ended
	Dec. 31, 2013
Condensed Financial Information of Parent Company Only Disclosure [Abstract]	'
Condensed balance sheets	'
	Balance Sheets
	(In thousands)
		December 31,
		2013			2012
	Assets
	Cash	$	122,001		$	57,303
	Loans	—			6,960
	Investments in subsidiaries	1,340,641			1,346,590
	Other assets	24,505			21,796
	Total assets	$	1,487,147		$	1,432,649
	Liabilities and Stockholders’ Equity
	Junior subordinated notes issued to capital trusts	$	152,065		$	152,065
	Other liabilities	8,400			4,814
	Stockholders’ equity	1,326,682			1,275,770
	Total liabilities and stockholders’ equity	$	1,487,147		$	1,432,649
Condensed statements of income	'
	Statements of Operations
	(In thousands)
		Years Ended December 31,
		2013			2012			2011
	Dividends from subsidiaries	$	80,500		$	146,000		$	—
	Interest and other income	4,215			1,682			3,410
	Interest and other expense	7,143			7,117			6,248
	Income (loss) before income tax benefit and equity in undistributed net income (loss) of subsidiaries	77,572			140,565			(2,838		)
	Income tax benefit	(1,223		)	(2,192		)	(1,151		)
	Income (loss) before equity in undistributed net income of subsidiaries	78,795			142,757			(1,687		)
	Equity in undistributed net income (loss) of subsidiaries	19,660			(52,383		)	40,415
	Net income	98,455			90,374			38,728
	Dividends and discount accretion on preferred shares	—			3,269			10,414
	Net income available to common stockholders	$	98,455		$	87,105		$	28,314
Condensed statements of cash flows	'
	Statements of Cash Flows
	(In thousands)
		Years Ended December 31,
		2013			2012			2011
	Cash Flows From Operating Activities
	Net income	$	98,455		$	90,374		$	38,728
	Adjustments to reconcile net income to net cash provided by operating activities:
	Amortization of restricted stock awards	4,280			3,544			3,277
	Compensation expense for stock option grants	1,176			1,262			1,559
	Equity in undistributed net income of subsidiaries	(19,660		)	52,383			(40,415		)
	Change in other assets and other liabilities	(1,460		)	(5,064		)	8,275
	Net cash provided by operating activities	82,791			142,499			11,424
	Cash Flows From Investing Activities
	Net decrease in loans	6,960			21,010			18,009
	Net cash provided by investing activities	6,960			21,010			18,009
	Cash Flows From Financing Activities
	Treasury stock transactions, net	(1,672		)	(249		)	(1,149		)
	Stock options exercised	1,014			154			1,903
	Excess tax benefits from share-based payment arrangements	(325		)	(390		)	(53		)
	Dividends paid on common stock	(24,070		)	(7,101		)	(2,164		)
	Dividends paid on preferred stock	—			(3,239		)	(9,799		)
	Repurchase of preferred stock and warrant	—			(197,518		)	—
	Redemption of on junior subordinated notes issued to capital trusts	—			(6,186		)	—
	Net cash used in financing activities	(25,053		)	(214,529		)	(11,262		)
	Net increase (decrease) in cash	64,698			(51,020		)	18,171
	Cash:
	Beginning of year	57,303			108,323			90,152
	End of year	$	122,001		$	57,303		$	108,323

Significant_Accounting_Policie3

Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2013
	category
	element
	rating
	indicator
	instrument
Troubled debt restructurings:	'
Number of notes into which a note is restructured (in instruments)	2
Allowance for loan and lease losses:	'
Number of elements in allowance for loan losses	3
Number of categories of commercial related loans for which a general loan loss reserve	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)	'13 years
Period for computing average losses (in years)	'12 years
Number of indicators for which correlation to charge-offs is tested	20
Time horizon over which forecast is applied (in years)	'1 year
Maximum	'
Cash and cash equivalents:	'
Term of original maturity to classify instrument as cash equivalent (in days)	'90 days
Allowance for loan and lease losses:	'
Period in which external appraisal on real estate secured impaired loan was obtained (in months)	'12 months
Lease investments:	'
Life of leased equipment under operating leases (in years)	'5 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
MB Financial Bank	'
Significant Accounting Policies	'
Number of wholly owned subsidiaries	2
MB Financial Bank | Chicago, Illinois	'
Significant Accounting Policies	'
Number of banking offices	84

Significant_Accounting_Policie4

Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Premises and Equipment	'	'	'
Impairment charge	'	$2,190	$1,594
Land improvements	'	'	'
Premises and Equipment	'	'	'
Estimated useful life, minimum (in years)	'15 years	'	'
Minimum	'	'	'
Finite-Lived Intangible Assets, Net [Abstract]	'	'	'
Amortization period, minimum (in years)	'4 years	'	'
Minimum | Furniture and equipment	'	'	'
Premises and Equipment	'	'	'
Estimated useful life, minimum (in years)	'5 years	'	'
Minimum | Buildings and building improvements	'	'	'
Premises and Equipment	'	'	'
Estimated useful life, minimum (in years)	'5 years	'	'
Maximum	'	'	'
Finite-Lived Intangible Assets, Net [Abstract]	'	'	'
Amortization period, minimum (in years)	'15 years	'	'
Maximum | Furniture and equipment	'	'	'
Premises and Equipment	'	'	'
Estimated useful life, minimum (in years)	'10 years	'	'
Maximum | Buildings and building improvements	'	'	'
Premises and Equipment	'	'	'
Estimated useful life, minimum (in years)	'39 years	'	'

Significant_Accounting_Policie5

Significant Accounting Policies (Details 3) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	segment
Basic and diluted earnings per common share:	'	'	'
Net income	$98,455	$90,374	$38,728
Less: preferred stock dividends and discount accretion	'	3,269	10,414
Net income available to common stockholders	98,455	87,105	28,314
Earnings allocated to common stockholders	98,453	87,102	28,281
Weighted average shares outstanding for diluted earnings per common share	54,993,865	54,505,976	54,337,280
Basic earnings per common share	$1.81	$1.61	$0.52
Diluted earnings per common share	$1.79	$1.60	$0.52
Segment Reporting	'	'	'
Number of reportable segments	2	'	'
Common Stock	'	'	'
Basic and diluted earnings per common share:	'	'	'
Distributed earnings allocated to common stock	24,290	7,149	2,185
Undistributed earnings	74,165	83,225	36,543
Net income	98,455	90,374	38,728
Net income available to common stockholders	98,455	87,105	28,314
Weighted average shares outstanding for basic earnings per common share	54,509,612	54,270,297	54,057,158
Dilutive effect of equity awards	484,253	235,679	280,122
Weighted average shares outstanding for diluted earnings per common share	54,993,865	54,505,976	54,337,280
Participating Securities	'	'	'
Basic and diluted earnings per common share:	'	'	'
Less: earnings and dividends allocated to participating securities	$2	$3	$33

Business_Combinations_Details

Business Combinations (Details) (USD $)	0 Months Ended				0 Months Ended
	Jul. 14, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 28, 2012
					Celtic [Member]
Assets	'	'	'	'	'
Cash and cash equivalents	'	'	$27,010,000	'	$31,647,000
Investment securities available for sale	'	'	'	'	635,000
Loans, net of discount	'	'	'	'	32,933,000
Premises and equipment	'	'	'	'	81,000
Goodwill	'	0	36,300,000	'	36,300,000
Other intangible	'	'	'	'	5,028,000
Other assets	'	'	'	'	27,323,000
Total assets	'	'	'	'	133,947,000
LIABILITIES	'	'	'	'	'
Accrued expenses and other liabilities	'	'	'	'	75,290,000
Total liabilities	'	'	'	'	75,290,000
Cash paid (received) on acquisition	'	'	'	'	-58,657,000
Net gain recorded on acquisition	'	'	'	'	0
Business Combination, Announced identifiable Assets To Be Acquired and Liabilities To Be Assumed, Assets	'	5,700,000,000	'	'	'
Business Combination, Announced Identifiable Assets To Be Acquired and Liabilities To Be Assumed, Loans	'	3,600,000,000	'	'	'
Business Combination, Announced Identifiable Assets To Be Acquired and Liabilities To Be Assumed, Deposits	'	$3,700,000,000	'	'	'
Business Combination, Consideration To Be Transferred, Share Conversion	0.64318	'	'	'	'
Business Combination, Consideration To Be Transferred, Amount Per Share	$4.08	'	'	'	'

Restrictions_on_Cash_and_Due_F1

Restrictions on Cash and Due From Banks (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Restrictions on Cash and Due from Banks [Abstract]	'	'
Required reserve balances in cash or on deposits with Federal Reserve Bank	$75.10	$64.40

Investment_Securities_Details

Investment Securities (Details) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Available for Sale	'	'	'	'
Amortized Cost	'	$1,111,922	$1,808,521	'
Gross Unrealized Gains	'	13,928	66,005	'
Gross Unrealized Losses	'	-6,938	-6,355	'
Fair Value	'	1,118,912	1,868,171	'
Held to Maturity	'	'	'	'
Investment securities held to maturity	'	1,182,533	493,421	'
Gross Unrealized Gains	'	20,762	42,260	'
Gross Unrealized Losses	'	-4,366	0	'
Investment Securities held to maturity	'	1,198,929	535,681	'
Total Available for Sale and Held to Maturity Investment Securities	'	'	'	'
Amortized Cost	'	2,294,455	2,301,942	'
Gross Unrealized Gains	'	34,690	108,265	'
Gross Unrealized Losses	'	-11,304	-6,355	'
Fair Value	'	2,317,841	2,403,852	'
Transfer of investment securities available for sale to investment securities held to maturity	656,600	656,617	0	0
U.S. Government sponsored agencies and enterprises	'	'	'	'
Available for Sale	'	'	'	'
Amortized Cost	'	50,486	38,605	'
Gross Unrealized Gains	'	1,704	2,710	'
Gross Unrealized Losses	'	-122	0	'
Fair Value	'	52,068	41,315	'
States and political subdivisions	'	'	'	'
Available for Sale	'	'	'	'
Amortized Cost	'	19,398	679,991	'
Gross Unrealized Gains	'	22	45,571	'
Gross Unrealized Losses	'	-277	-543	'
Fair Value	'	19,143	725,019	'
Held to Maturity	'	'	'	'
Investment securities held to maturity	'	932,955	237,563	'
Gross Unrealized Gains	'	7,584	21,039	'
Gross Unrealized Losses	'	-4,366	0	'
Investment Securities held to maturity	'	936,173	258,602	'
Total Available for Sale and Held to Maturity Investment Securities	'	'	'	'
Percentage of securities consisting general obligation issues	'	90.00%	'	'
States and political subdivisions | State of Illinois	'	'	'	'
Total Available for Sale and Held to Maturity Investment Securities	'	'	'	'
Percentage of investments issued by states and political subdivisions that were within the state of Illinois	'	27.00%	'	'
Residential mortgage-backed securities	'	'	'	'
Available for Sale	'	'	'	'
Amortized Cost	'	696,415	930,413	'
Gross Unrealized Gains	'	8,555	14,038	'
Gross Unrealized Losses	'	-3,737	-5,249	'
Fair Value	'	701,233	939,202	'
Held to Maturity	'	'	'	'
Investment securities held to maturity	'	249,578	255,858	'
Gross Unrealized Gains	'	13,178	21,221	'
Gross Unrealized Losses	'	0	0	'
Investment Securities held to maturity	'	262,756	277,079	'
Commercial mortgage-backed securities	'	'	'	'
Available for Sale	'	'	'	'
Amortized Cost	'	50,891	51,100	'
Gross Unrealized Gains	'	2,050	3,026	'
Gross Unrealized Losses	'	0	0	'
Fair Value	'	52,941	54,126	'
Corporate bonds	'	'	'	'
Available for Sale	'	'	'	'
Amortized Cost	'	284,083	97,014	'
Gross Unrealized Gains	'	1,597	213	'
Gross Unrealized Losses	'	-2,610	-553	'
Fair Value	'	283,070	96,674	'
Equity securities	'	'	'	'
Available for Sale	'	'	'	'
Amortized Cost	'	10,649	11,398	'
Gross Unrealized Gains	'	0	447	'
Gross Unrealized Losses	'	-192	-10	'
Fair Value	'	$10,457	$11,835	'

Investment_Securities_Details_

Investment Securities (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
	securitypositions	securitypositions
Available for Sale	'	'
Less Than 12 Months, Fair Value	$386,481,000	'
Less Than 12 Months, Unrealized Losses	-5,991,000	'
12 Months or More, Fair Value	49,635,000	'
12 Months or More, Unrealized Losses	-947,000	'
Total Fair Value	436,116,000	'
Total Unrealized Losses	-6,938,000	'
Total	'	'
Less Than 12 Months, Fair Value	621,497,000	386,350,000
Less Than 12 Months, Unrealized Losses	-10,321,000	6,189,000
12 Months or More, Fair Value	50,936,000	16,434,000
12 Months or More, Unrealized Losses	983,000	-166,000
Total Fair Value	672,433,000	402,784,000
Total Unrealized Losses	-11,304,000	6,355,000
Number of security positions in the investment portfolio in an unrealized loss position	345	117
U.S. Government sponsored agencies and enterprises	'	'
Available for Sale	'	'
Less Than 12 Months, Fair Value	18,598,000	'
Less Than 12 Months, Unrealized Losses	-122,000	'
12 Months or More, Fair Value	0	'
12 Months or More, Unrealized Losses	0	'
Total Fair Value	18,598,000	'
Total Unrealized Losses	-122,000	'
States and political subdivisions	'	'
Available for Sale	'	'
Less Than 12 Months, Fair Value	2,275,000	57,540,000
Less Than 12 Months, Unrealized Losses	-166,000	-543,000
12 Months or More, Fair Value	4,748,000	0
12 Months or More, Unrealized Losses	-111,000	0
Total Fair Value	7,023,000	57,540,000
Total Unrealized Losses	-277,000	-543,000
Held to maturity	'	'
Less Than 12 Months, Fair Value	235,016,000	'
Less Than 12 Months, Unrealized Losses	-4,330,000	'
12 Months or More, Fair Value	1,301,000	'
12 Months or More, Unrealized Losses	-36,000	'
Total Fair Value	236,317,000	'
Total Unrealized Losses	-4,366,000	'
Residential mortgage-backed securities	'	'
Available for Sale	'	'
Less Than 12 Months, Fair Value	232,807,000	270,539,000
Less Than 12 Months, Unrealized Losses	-2,905,000	-5,083,000
12 Months or More, Fair Value	44,182,000	16,434,000
12 Months or More, Unrealized Losses	-832,000	-166,000
Total Fair Value	276,989,000	286,973,000
Total Unrealized Losses	-3,737,000	-5,249,000
Corporate bonds	'	'
Available for Sale	'	'
Less Than 12 Months, Fair Value	122,344,000	58,241,000
Less Than 12 Months, Unrealized Losses	-2,606,000	-553,000
12 Months or More, Fair Value	705,000	'
12 Months or More, Unrealized Losses	-4,000	'
Total Fair Value	123,049,000	58,241,000
Total Unrealized Losses	-2,610,000	-553,000
Equity securities	'	'
Available for Sale	'	'
Less Than 12 Months, Fair Value	10,457,000	30,000
Less Than 12 Months, Unrealized Losses	-192,000	-10,000
12 Months or More, Fair Value	0	'
12 Months or More, Unrealized Losses	0	'
Total Fair Value	10,457,000	30,000
Total Unrealized Losses	($192,000)	($10,000)

Investment_Securities_Details_1

Investment Securities (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Realized net gains on the sale of investment securities available for sale	'	'	'
Realized gains	$15,000	$787,000	$647,000
Realized losses	-2,000	-8,000	-7,000
Impairment charges	-14,000	-224,000	0
Net (losses) gains	-1,000	555,000	640,000
Amortized Cost, Available for sale	'	'	'
Due in one year or less	504,000	'	'
Due after one year through five years	337,107,000	'	'
Due after five years through ten years	7,676,000	'	'
Due after ten years	8,680,000	'	'
Amortized Cost	1,111,922,000	1,808,521,000	'
Fair Value, Available for sale	'	'	'
Due in one year or less	505,000	'	'
Due after one year through five years	337,675,000	'	'
Due after five years through ten years	7,582,000	'	'
Due after ten years	8,519,000	'	'
Fair Value	1,118,912,000	1,868,171,000	'
Amortized Cost, Held to maturity	'	'	'
Due in one year or less	27,708,000	'	'
Due in after one year through five years	252,967,000	'	'
Due after five years through ten years	121,269,000	'	'
Due after ten years	531,011,000	'	'
Investment securities held to maturity	1,182,533,000	493,421,000	'
Fair value, Held to maturity	'	'	'
Due in one year or less	27,715,000	'	'
Due in after one year through five years	254,608,000	'	'
Due after five years through ten years	121,128,000	'	'
Due after ten years	532,722,000	'	'
Investment Securities held to maturity	1,198,929,000	535,681,000	'
Total Available for Sale and Held to Maturity Investment Securities	'	'	'
Amortized Cost	2,294,455,000	2,301,942,000	'
Fair Value	2,317,841,000	2,403,852,000	'
Carrying amounts of investment securities available for sale pledged as collateral	908,400,000	989,600,000	'
Investment securities pledged as collateral for Federal Home Loan Bank advances	29,000,000	32,100,000	'
Equity securities	'	'	'
Amortized Cost, Available for sale	'	'	'
Amortized Cost	10,649,000	11,398,000	'
Fair Value, Available for sale	'	'	'
Fair Value	10,457,000	11,835,000	'
Residential and commercial mortgage-backed securities	'	'	'
Amortized Cost, Available for sale	'	'	'
Amortized Cost	747,306,000	'	'
Fair Value, Available for sale	'	'	'
Fair Value	754,174,000	'	'
Residential mortgage-backed securities	'	'	'
Amortized Cost, Available for sale	'	'	'
Amortized Cost	696,415,000	930,413,000	'
Fair Value, Available for sale	'	'	'
Fair Value	701,233,000	939,202,000	'
Amortized Cost, Held to maturity	'	'	'
Investment securities held to maturity	249,578,000	255,858,000	'
Fair value, Held to maturity	'	'	'
Investment Securities held to maturity	$262,756,000	$277,079,000	'

Loans_Details

Loans (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
	investmentrating
Loans	'		'
Total loans, excluding covered loans	$5,476,831,000		$5,317,080,000
Covered loans	235,720,000		449,850,000
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	5,712,551,000	[1]	5,766,930,000	[1]
Net unearned income, including net deferred loan fees	1,900,000		1,100,000
Number of highest rating categories by rating services company	1		'
Number of highest rating categories to be achieved for classification as investment grade companies	4		'
Loans and Leases Receivable, Related Parties	24,000,000		'
Loans and Leases Receivable, Related Parties, Additions	2,700,000		'
Loans and Leases Receivable, Related Parties, Collections	-2,700,000		'
Loans pledged as collateral for Federal Home Loan Bank advances	518,400,000		28,400,000
Minimum	'		'
Loans	'		'
Percentage of collateral pledge of first mortgage loans as per agreement	133.00%		'
Percentage of collateral pledge of home equity loans as per agreement	250.00%		'
Commercial	'		'
Loans	'		'
Total loans, excluding covered loans	1,281,377,000		1,220,472,000
Covered loans	3,567,000		'
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	1,300,018,000		1,268,348,000
Commercial collateralized by assignment of lease payments	'		'
Loans	'		'
Total loans, excluding covered loans	1,494,188,000		1,303,020,000
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	1,494,188,000		1,303,020,000
Commercial real estate	'		'
Loans	'		'
Total loans, excluding covered loans	1,647,700,000		1,761,832,000
Covered loans	140,504,000		'
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	1,788,204,000		2,009,222,000
Residential real estate	'		'
Loans	'		'
Total loans, excluding covered loans	314,440,000		314,359,000
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	316,275,000		316,948,000
Construction real estate	'		'
Loans	'		'
Total loans, excluding covered loans	141,253,000		110,261,000
Covered loans	48,313,000		'
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	189,566,000		228,621,000
Indirect vehicle	'		'
Loans	'		'
Total loans, excluding covered loans	262,632,000		208,633,000
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	262,632,000		208,633,000
Home equity lines	'		'
Loans	'		'
Total loans, excluding covered loans	268,289,000		305,186,000
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	268,396,000		305,651,000
Other consumer	'		'
Loans	'		'
Total loans, excluding covered loans	66,952,000		93,317,000
Loans and Leases Receivable, Net of Deferred Income Including Covered Loans	$93,272,000		$126,487,000
[1]	Gross loan balances at December 31, 2013 and 2012 are net of unearned income, including net deferred loan fees of $1.9 million and $1.1 million, respectively.

Loans_Details_2

Loans (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	$5,476,831,000		$5,317,080,000		'
Total loans	5,712,551,000	[1]	5,766,930,000	[1]	'
Period past due of recorded investment in loans (in days)	'90 days		'		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Reduction in interest income associated with loans on nonaccrual status	4,700,000		5,600,000		11,900,000
Non-performing substandard and doubtful loans	80,700,000		85,500,000		'
Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	4,335,981,000		4,064,532,000		'
Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	68,277,000		134,025,000		'
Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	156,570,000		193,575,000		'
Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	3,690,000		3,453,000		'
Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	4,564,518,000		4,395,585,000		'
Performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	886,867,000		890,562,000		'
Non-performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	56,339,000		69,836,000		'
30-59 days, past due	14,325,000		3,171,000		'
60-89 days, past due	3,283,000		3,718,000		'
Loans past due, 90 days or more	32,614,000		40,261,000		'
Total, past due	50,222,000		47,150,000		'
Total loans, excluding covered loans	25,446,000		30,933,000		'
Total loans	106,561,000		116,986,000		'
Commercial	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	1,273,302,000		1,215,957,000		'
30-59 days, past due	5,952,000		639,000		'
60-89 days, past due	626,000		754,000		'
Loans past due, 90 days or more	1,497,000		3,122,000		'
Total, past due	8,075,000		4,515,000		'
Total loans, excluding covered loans	1,281,377,000		1,220,472,000		'
Total loans	1,300,018,000		1,268,348,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	17,781,000		23,886,000		'
Loans past due 90 days or more and still accruing	0		229,000		'
Commercial | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	1,193,114,000		1,136,294,000		'
Commercial | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	26,637,000		33,068,000		'
Commercial | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	61,000,000		50,895,000		'
Commercial | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	626,000		215,000		'
Commercial | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	1,281,377,000		1,220,472,000		'
Commercial collateralized by assignment of lease payments	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	1,489,391,000		1,288,341,000		'
30-59 days, past due	3,841,000		11,252,000		'
60-89 days, past due	656,000		2,847,000		'
Loans past due, 90 days or more	300,000		580,000		'
Total, past due	4,797,000		14,679,000		'
Total loans, excluding covered loans	1,494,188,000		1,303,020,000		'
Total loans	1,494,188,000		1,303,020,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	4,276,000		1,180,000		'
Loans past due 90 days or more and still accruing	291,000		222,000		'
Commercial collateralized by assignment of lease payments | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	1,486,899,000		1,292,241,000		'
Commercial collateralized by assignment of lease payments | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	553,000		3,322,000		'
Commercial collateralized by assignment of lease payments | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	6,736,000		7,457,000		'
Commercial collateralized by assignment of lease payments | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Commercial collateralized by assignment of lease payments | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	1,494,188,000		1,303,020,000		'
Commercial real estate	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	1,647,700,000		1,761,832,000		'
Total loans	1,788,204,000		2,009,222,000		'
Healthcare	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	213,665,000		192,039,000		'
30-59 days, past due	0		0		'
60-89 days, past due	0		0		'
Loans past due, 90 days or more	3,064,000		3,238,000		'
Total, past due	3,064,000		3,238,000		'
Total loans, excluding covered loans	216,729,000		195,277,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	3,064,000		3,238,000		'
Loans past due 90 days or more and still accruing	0		0		'
Healthcare | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	189,705,000		170,265,000		'
Healthcare | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	21,186,000		21,774,000		'
Healthcare | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	2,774,000		0		'
Healthcare | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	3,064,000		3,238,000		'
Healthcare | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	216,729,000		195,277,000		'
Industrial	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	372,975,000		402,813,000		'
30-59 days, past due	5,465,000		548,000		'
60-89 days, past due	0		424,000		'
Loans past due, 90 days or more	1,404,000		7,700,000		'
Total, past due	6,869,000		8,672,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	15,265,000		19,179,000		'
Loans past due 90 days or more and still accruing	155,000		147,000		'
Industrial | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	345,236,000		355,218,000		'
Industrial | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	5,328,000		15,243,000		'
Industrial | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	29,280,000		41,024,000		'
Industrial | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Industrial | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	379,844,000		411,485,000		'
Multifamily	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	302,456,000		353,966,000		'
30-59 days, past due	3,078,000		1,282,000		'
60-89 days, past due	181,000		0		'
Loans past due, 90 days or more	2,226,000		3,103,000		'
Total, past due	5,485,000		4,385,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	5,145,000		7,225,000		'
Loans past due 90 days or more and still accruing	0		0		'
Multifamily | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	296,179,000		318,991,000		'
Multifamily | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	342,000		25,297,000		'
Multifamily | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	11,420,000		14,063,000		'
Multifamily | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Multifamily | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	307,941,000		358,351,000		'
Retail	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	334,198,000		375,900,000		'
30-59 days, past due	328,000		6,933,000		'
60-89 days, past due	2,816,000		518,000		'
Loans past due, 90 days or more	7,258,000		9,331,000		'
Total, past due	10,402,000		16,782,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	2,969,000		17,019,000		'
Loans past due 90 days or more and still accruing	0		0		'
Retail | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	316,420,000		340,919,000		'
Retail | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	10,660,000		25,096,000		'
Retail | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	17,520,000		26,667,000		'
Retail | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Retail | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	344,600,000		392,682,000		'
Office	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	155,936,000		186,665,000		'
30-59 days, past due	0		742,000		'
60-89 days, past due	0		280,000		'
Loans past due, 90 days or more	2,066,000		1,125,000		'
Total, past due	2,066,000		2,147,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	11,703,000		3,263,000		'
Loans past due 90 days or more and still accruing	0		0		'
Office | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	151,393,000		159,056,000		'
Office | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	2,682,000		7,120,000		'
Office | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	3,927,000		22,636,000		'
Office | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Office | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	158,002,000		188,812,000		'
Other	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	233,464,000		210,456,000		'
30-59 days, past due	4,898,000		851,000		'
60-89 days, past due	259,000		1,837,000		'
Loans past due, 90 days or more	1,963,000		2,081,000		'
Total, past due	7,120,000		4,769,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	19,991,000		9,437,000		'
Loans past due 90 days or more and still accruing	0		0		'
Other | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	217,188,000		193,824,000		'
Other | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	349,000		2,553,000		'
Other | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	23,047,000		18,848,000		'
Other | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Other | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	240,584,000		215,225,000		'
Residential real estate	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	302,362,000		306,927,000		'
30-59 days, past due	1,422,000		382,000		'
60-89 days, past due	1,030,000		1,248,000		'
Loans past due, 90 days or more	9,626,000		5,802,000		'
Total, past due	12,078,000		7,432,000		'
Total loans, excluding covered loans	314,440,000		314,359,000		'
Total loans	316,275,000		316,948,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	13,009,000		10,943,000		'
Loans past due 90 days or more and still accruing	0		0		'
Residential real estate | Performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	301,431,000		303,416,000		'
Residential real estate | Non-performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	13,009,000		10,943,000		'
Construction real estate	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	138,563,000		106,158,000		'
30-59 days, past due	391,000		1,139,000		'
60-89 days, past due	0		97,000		'
Loans past due, 90 days or more	2,299,000		2,867,000		'
Total, past due	2,690,000		4,103,000		'
Total loans, excluding covered loans	141,253,000		110,261,000		'
Total loans	189,566,000		228,621,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	475,000		1,028,000		'
Loans past due 90 days or more and still accruing	0		0		'
Construction real estate | Pass	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	139,847,000		97,724,000		'
Construction real estate | Special Mention	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	540,000		552,000		'
Construction real estate | Substandard	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	866,000		11,985,000		'
Construction real estate | Doubtful	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	0		0		'
Construction real estate | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	141,253,000		110,261,000		'
Indirect vehicle	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	259,488,000		206,126,000		'
30-59 days, past due	2,210,000		1,588,000		'
60-89 days, past due	657,000		498,000		'
Loans past due, 90 days or more	277,000		421,000		'
Total, past due	3,144,000		2,507,000		'
Total loans, excluding covered loans	262,632,000		208,633,000		'
Total loans	262,632,000		208,633,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	1,459,000		1,494,000		'
Loans past due 90 days or more and still accruing	0		0		'
Indirect vehicle | Total risk rated category	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	262,632,000		208,633,000		'
Indirect vehicle | Performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	261,173,000		207,139,000		'
Indirect vehicle | Non-performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	1,459,000		1,494,000		'
Home equity lines	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	257,219,000		291,737,000		'
30-59 days, past due	1,725,000		3,557,000		'
60-89 days, past due	2,165,000		1,888,000		'
Loans past due, 90 days or more	7,180,000		8,004,000		'
Total, past due	11,070,000		13,449,000		'
Total loans, excluding covered loans	268,289,000		305,186,000		'
Total loans	268,396,000		305,651,000		'
Home equity lines | Performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	257,320,000		286,700,000		'
Home equity lines | Non-performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	10,969,000		18,486,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	10,969,000		17,486,000		'
Loans past due 90 days or more and still accruing	0		1,000,000		'
Other consumer	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	66,866,000		93,266,000		'
30-59 days, past due	81,000		47,000		'
60-89 days, past due	1,000		0		'
Loans past due, 90 days or more	4,000		4,000		'
Total, past due	86,000		51,000		'
Total loans, excluding covered loans	66,952,000		93,317,000		'
Total loans	93,272,000		126,487,000		'
Other consumer | Performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	66,943,000		93,307,000		'
Other consumer | Non-performing	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	9,000		10,000		'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	9,000		9,000		'
Loans past due 90 days or more and still accruing	0		1,000		'
Other Loans [Member]	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Total loans, excluding covered loans	912,313,000		921,495,000		'
Gross loans, excluding covered loans	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	5,399,885,000		5,230,351,000		'
30-59 days, past due	29,391,000		28,960,000		'
60-89 days, past due	8,391,000		10,391,000		'
Loans past due, 90 days or more	39,164,000		47,378,000		'
Total, past due	76,946,000		86,729,000		'
Total loans, excluding covered loans	5,476,831,000		5,317,080,000		'
Covered loans	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	135,717,000		301,260,000		'
30-59 days, past due	902,000		5,831,000		'
60-89 days, past due	3,346,000		7,478,000		'
Loans past due, 90 days or more	95,755,000		135,281,000		'
Total, past due	100,003,000		148,590,000		'
Total loans	235,720,000		449,850,000		'
Loans	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	5,535,602,000	[2]	5,531,611,000	[2]	'
30-59 days, past due	30,293,000	[2]	34,791,000	[2]	'
60-89 days, past due	11,737,000	[2]	17,869,000	[2]	'
Loans past due, 90 days or more	134,919,000	[2]	182,659,000	[2]	'
Total, past due	176,949,000	[2]	235,319,000	[2]	'
Total loans	5,712,551,000	[2]	5,766,930,000	[2]	'
Recorded investment in nonaccrual loans and loans past due ninety days or more and still accruing	'		'		'
Nonaccrual	106,115,000		115,387,000		'
Loans past due 90 days or more and still accruing	446,000		1,599,000		'
Non-covered loans related to FDIC transactions	'		'		'
Contractual aging of the recorded investment in loans	'		'		'
Current	13,541,000	[3]	12,752,000	[3]	'
30-59 days, past due	163,000	[3]	312,000	[3]	'
60-89 days, past due	391,000	[3]	1,542,000	[3]	'
Loans past due, 90 days or more	6,550,000	[3]	7,115,000	[3]	'
Total, past due	7,104,000	[3]	8,969,000	[3]	'
Total loans	$20,645,000	[3]	$21,721,000	[3]	'
[1]	Gross loan balances at December 31, 2013 and 2012 are net of unearned income, including net deferred loan fees of $1.9 million and $1.1 million, respectively.
[2]	Includes loans related to the InBank FDIC-assisted transaction completed by MB Financial Bank in 2009.
[3]	Loans related to the InBank FDIC-assisted transaction completed by MB Financial Bank in 2009.

Loans_Details_3

Loans (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	$135,041	$144,992	'
Recorded Investment	128,521	122,264	'
Partial Charge-Offs	6,520	22,728	'
Allowance for Loan Losses Allocated	17,368	16,941	'
Average Recorded Investment	136,454	119,252	267,800
Interest Income Recognized	1,870	1,592	'
Interest income recognized on cash basis	1,870	1,592	2,959
Restructured loans	21,074	'	'
Performing	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	29,400	21,300	'
Non-performing	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	25,000	28,400	'
Commercial	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	1,251	'	'
Commercial collateralized by assignment of lease payments	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	3,401	'	'
Healthcare	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	3,164	'	'
Industrial	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	2,570	'	'
Multifamily	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	1,224	'	'
Retail	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	862	'	'
Office	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	0	'	'
Other	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	84	'	'
Residential real estate	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	2,713	'	'
Construction real estate	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	0	'	'
Indirect vehicle	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	171	'	'
Home equity lines	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	5,634	'	'
Other consumer	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Restructured loans	0	'	'
Impaired financing receivable with no allowance | Commercial	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	8,903	10,993	'
Recorded Investment	8,903	9,505	'
Partial Charge-Offs	0	1,488	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	8,259	14,089	'
Interest Income Recognized	0	105	'
Impaired financing receivable with no allowance | Commercial collateralized by assignment of lease payments	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	3,401	390	'
Recorded Investment	3,401	390	'
Partial Charge-Offs	0	0	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	1,030	278	'
Interest Income Recognized	6	9	'
Impaired financing receivable with no allowance | Healthcare	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	0	10,943	'
Recorded Investment	0	3,238	'
Partial Charge-Offs	0	7,705	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	2,698	2,751	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Industrial	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	7,560	16,891	'
Recorded Investment	7,560	14,940	'
Partial Charge-Offs	0	1,951	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	8,900	16,374	'
Interest Income Recognized	0	29	'
Impaired financing receivable with no allowance | Multifamily	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	1,166	800	'
Recorded Investment	1,166	800	'
Partial Charge-Offs	0	0	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	758	1,340	'
Interest Income Recognized	11	14	'
Impaired financing receivable with no allowance | Retail	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	4,466	5,372	'
Recorded Investment	4,466	4,917	'
Partial Charge-Offs	0	455	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	3,628	9,241	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Office	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	559	1,568	'
Recorded Investment	527	1,568	'
Partial Charge-Offs	32	0	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	922	1,151	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Other	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	2,963	4,860	'
Recorded Investment	2,963	4,860	'
Partial Charge-Offs	0	0	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	4,380	6,005	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Residential real estate	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	4,234	3,097	'
Recorded Investment	4,234	2,711	'
Partial Charge-Offs	0	386	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	3,260	6,476	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Construction real estate	'	'	'
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 Losses Allocated	0	0	'
Average Recorded Investment	0	577	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Indirect vehicle	'	'	'
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 Losses Allocated	0	0	'
Average Recorded Investment	0	0	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Home equity lines	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	577	2,558	'
Recorded Investment	577	2,558	'
Partial Charge-Offs	0	0	'
Allowance for Loan Losses Allocated	0	0	'
Average Recorded Investment	797	8,976	'
Interest Income Recognized	0	0	'
Impaired financing receivable with no allowance | Other consumer	'	'	'
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 Losses Allocated	0	0	'
Average Recorded Investment	0	182	'
Interest Income Recognized	0	0	'
Impaired financing receivable with allowance | Commercial	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	8,923	14,484	'
Recorded Investment	8,919	14,381	'
Partial Charge-Offs	4	103	'
Allowance for Loan Losses Allocated	4,284	3,620	'
Average Recorded Investment	13,476	8,455	'
Interest Income Recognized	4	0	'
Impaired financing receivable with allowance | Commercial collateralized by assignment of lease payments	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	1,060	885	'
Recorded Investment	1,060	885	'
Partial Charge-Offs	0	0	'
Allowance for Loan Losses Allocated	144	188	'
Average Recorded Investment	1,279	1,130	'
Interest Income Recognized	192	95	'
Impaired financing receivable with allowance | Healthcare	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	3,186	0	'
Recorded Investment	3,064	0	'
Partial Charge-Offs	122	0	'
Allowance for Loan Losses Allocated	382	0	'
Average Recorded Investment	8,189	3,901	'
Interest Income Recognized	0	0	'
Impaired financing receivable with allowance | Industrial	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	7,707	5,525	'
Recorded Investment	7,705	4,238	'
Partial Charge-Offs	2	1,287	'
Allowance for Loan Losses Allocated	3,038	1,255	'
Average Recorded Investment	3,699	2,443	'
Interest Income Recognized	0	0	'
Impaired financing receivable with allowance | Multifamily	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	5,374	8,233	'
Recorded Investment	5,374	7,249	'
Partial Charge-Offs	0	984	'
Allowance for Loan Losses Allocated	1,661	2,284	'
Average Recorded Investment	6,443	5,847	'
Interest Income Recognized	340	180	'
Impaired financing receivable with allowance | Retail	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	14,169	23,144	'
Recorded Investment	12,428	17,257	'
Partial Charge-Offs	1,741	5,887	'
Allowance for Loan Losses Allocated	1,511	3,604	'
Average Recorded Investment	12,885	10,058	'
Interest Income Recognized	280	293	'
Impaired financing receivable with allowance | Office	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	2,442	1,706	'
Recorded Investment	2,442	1,695	'
Partial Charge-Offs	0	11	'
Allowance for Loan Losses Allocated	791	522	'
Average Recorded Investment	4,045	1,904	'
Interest Income Recognized	0	0	'
Impaired financing receivable with allowance | Other	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	20,367	4,661	'
Recorded Investment	17,029	4,577	'
Partial Charge-Offs	3,338	84	'
Allowance for Loan Losses Allocated	796	1,263	'
Average Recorded Investment	12,868	6,082	'
Interest Income Recognized	20	16	'
Impaired financing receivable with allowance | Residential real estate	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	13,496	10,565	'
Recorded Investment	12,710	10,565	'
Partial Charge-Offs	786	0	'
Allowance for Loan Losses Allocated	3,119	2,858	'
Average Recorded Investment	12,966	3,417	'
Interest Income Recognized	245	227	'
Impaired financing receivable with allowance | Construction real estate	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	475	4,552	'
Recorded Investment	475	2,167	'
Partial Charge-Offs	0	2,385	'
Allowance for Loan Losses Allocated	227	497	'
Average Recorded Investment	1,603	3,775	'
Interest Income Recognized	0	61	'
Impaired financing receivable with allowance | Indirect vehicle	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	173	0	'
Recorded Investment	123	0	'
Partial Charge-Offs	50	0	'
Allowance for Loan Losses Allocated	57	0	'
Average Recorded Investment	86	0	'
Interest Income Recognized	0	0	'
Impaired financing receivable with allowance | Home equity lines	'	'	'
Loans individually evaluated for impairment by class of loans	'	'	'
Unpaid Principal Balance	23,840	13,765	'
Recorded Investment	23,395	13,763	'
Partial Charge-Offs	445	2	'
Allowance for Loan Losses Allocated	1,358	850	'
Average Recorded Investment	24,283	4,800	'
Interest Income Recognized	772	563	'
Impaired financing receivable with allowance | Other consumer	'	'	'
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 Losses Allocated	0	0	'
Average Recorded Investment	0	0	'
Interest Income Recognized	$0	$0	'

Loans_Details_4

Loans (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
	loan	loan
Restructured loans	'	'
Number of separate notes restructured into A/B by the company	2	'
Minimum period of sustained repayment required to return the note to accrual status (in months)	'6 months	'
Restructured loans representing A/B structures	$1,100,000	$3,100,000
Number of A/B structures represented by restructured loans	1	1
Redefaulted loans	843,000	'
Period past due of recorded redefaulted loans (in days)	'90 days	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	21,074,000	'
Performing	'	'
Restructured loans	'	'
Number of loans	21	61
Pre-Modification Recorded Investment	3,715,000	11,174,000
Post-Modification Recorded Investment	3,715,000	11,098,000
Charge-offs and Specific Reserves	0	76,000
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Beginning balance	21,256,000	'
Additions	3,715,000	'
Charge-offs	-71,000	'
Principal payments, net	-2,813,000	'
Removals	0	'
Transfer to other real estate owned	0	'
Transfer from non-performing/performing	8,603,000	'
Transfer to non-performing/performing	-1,260,000	'
Ending balance	29,430,000	21,256,000
Non-performing	'	'
Restructured loans	'	'
Number of loans	75	60
Pre-Modification Recorded Investment	17,359,000	11,474,000
Post-Modification Recorded Investment	17,196,000	11,239,000
Charge-offs and Specific Reserves	3,184,000	1,027,000
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Beginning balance	28,418,000	'
Additions	17,359,000	'
Charge-offs	-3,810,000	'
Principal payments, net	-8,901,000	'
Removals	-565,000	'
Transfer to other real estate owned	-206,000	'
Transfer from non-performing/performing	1,260,000	'
Transfer to non-performing/performing	-8,603,000	'
Ending balance	24,952,000	28,418,000
Commercial	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	1,251,000	'
Commercial | Non-performing	'	'
Restructured loans	'	'
Number of loans	2	4
Pre-Modification Recorded Investment	1,251,000	3,305,000
Post-Modification Recorded Investment	1,251,000	3,305,000
Charge-offs and Specific Reserves	673,000	73,000
Commercial collateralized by assignment of lease payments	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	3,401,000	'
Commercial collateralized by assignment of lease payments | Non-performing	'	'
Restructured loans	'	'
Number of loans	1	1
Pre-Modification Recorded Investment	3,401,000	202,000
Post-Modification Recorded Investment	3,401,000	202,000
Charge-offs and Specific Reserves	0	168,000
Multifamily	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	1,224,000	'
Multifamily | Performing	'	'
Restructured loans	'	'
Number of loans	1	2
Pre-Modification Recorded Investment	601,000	262,000
Post-Modification Recorded Investment	601,000	262,000
Charge-offs and Specific Reserves	0	0
Multifamily | Non-performing	'	'
Restructured loans	'	'
Number of loans	2	2
Pre-Modification Recorded Investment	623,000	333,000
Post-Modification Recorded Investment	623,000	333,000
Charge-offs and Specific Reserves	169,000	220,000
Healthcare	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	3,164,000	'
Healthcare | Non-performing	'	'
Restructured loans	'	'
Number of loans	1	'
Pre-Modification Recorded Investment	3,164,000	'
Post-Modification Recorded Investment	3,164,000	'
Charge-offs and Specific Reserves	496,000	'
Industrial	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	2,570,000	'
Industrial | Non-performing	'	'
Restructured loans	'	'
Number of loans	4	1
Pre-Modification Recorded Investment	2,570,000	284,000
Post-Modification Recorded Investment	2,570,000	284,000
Charge-offs and Specific Reserves	1,425,000	77,000
Retail	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	862,000	'
Retail | Performing	'	'
Restructured loans	'	'
Number of loans	'	1
Pre-Modification Recorded Investment	'	236,000
Post-Modification Recorded Investment	'	236,000
Charge-offs and Specific Reserves	'	0
Retail | Non-performing	'	'
Restructured loans	'	'
Number of loans	3	4
Pre-Modification Recorded Investment	862,000	818,000
Post-Modification Recorded Investment	862,000	818,000
Charge-offs and Specific Reserves	235,000	204,000
Other	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	84,000	'
Other | Non-performing	'	'
Restructured loans	'	'
Number of loans	1	1
Pre-Modification Recorded Investment	84,000	157,000
Post-Modification Recorded Investment	84,000	157,000
Charge-offs and Specific Reserves	23,000	50,000
Residential real estate	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	2,713,000	'
Residential real estate | Performing	'	'
Restructured loans	'	'
Number of loans	6	4
Pre-Modification Recorded Investment	910,000	1,575,000
Post-Modification Recorded Investment	910,000	1,575,000
Charge-offs and Specific Reserves	0	0
Residential real estate | Non-performing	'	'
Restructured loans	'	'
Number of loans	9	5
Pre-Modification Recorded Investment	1,803,000	1,092,000
Post-Modification Recorded Investment	1,682,000	857,000
Charge-offs and Specific Reserves	121,000	235,000
Construction real estate	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	0	'
Construction real estate | Performing	'	'
Restructured loans	'	'
Number of loans	'	1
Pre-Modification Recorded Investment	'	1,158,000
Post-Modification Recorded Investment	'	1,158,000
Charge-offs and Specific Reserves	'	0
Indirect vehicle	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	171,000	'
Indirect vehicle | Non-performing	'	'
Restructured loans	'	'
Number of loans	26	'
Pre-Modification Recorded Investment	171,000	'
Post-Modification Recorded Investment	129,000	'
Charge-offs and Specific Reserves	42,000	'
Home equity lines	'	'
Troubled Debt Restructuring Activity [Roll Forward]	'	'
Ending balance	5,634,000	'
Home equity lines | Performing	'	'
Restructured loans	'	'
Number of loans	14	53
Pre-Modification Recorded Investment	2,204,000	7,943,000
Post-Modification Recorded Investment	2,204,000	7,867,000
Charge-offs and Specific Reserves	0	76,000
Home equity lines | Non-performing	'	'
Restructured loans	'	'
Number of loans	26	42
Pre-Modification Recorded Investment	3,430,000	5,283,000
Post-Modification Recorded Investment	3,430,000	5,283,000
Charge-offs and Specific Reserves	$0	$0

Loans_Details_5

Loans (Details 5) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	$5,361
Extended Maturity, Delay in Payments and Reduction of Interest Rate	205
Extended Maturity and Delay in Payments or Reduction of Interest Rate	5,719
Extended Maturity, Delay in Payments and Reduction of Amount	3,164
Extended Maturity	3,833
Delay in Payments or Reduction of Interest Rate	2,792
Total	21,074
Commercial	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	42
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	1,209
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	1,251
Commercial collateralized by assignment of lease payments	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	3,401
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	3,401
Healthcare	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	3,164
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	3,164
Industrial	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	2,570
Delay in Payments or Reduction of Interest Rate	0
Total	2,570
Multifamily	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	187
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	601
Delay in Payments or Reduction of Interest Rate	436
Total	1,224
Retail	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	256
Extended Maturity, Delay in Payments and Reduction of Interest Rate	205
Extended Maturity and Delay in Payments or Reduction of Interest Rate	401
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	862
Office	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	0
Other	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	84
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	84
Residential real estate	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	1,917
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	178
Delay in Payments or Reduction of Interest Rate	618
Total	2,713
Construction real estate	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	0
Indirect vehicle	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	44
Delay in Payments or Reduction of Interest Rate	127
Total	171
Home equity lines	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	2,875
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	708
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	440
Delay in Payments or Reduction of Interest Rate	1,611
Total	5,634
Other consumer	'
Activity in the allowance for loan losses, balance in allowance for loan losses and recorded investment in loans by portfolio segment and based on impairment method	'
Extended Maturity, Amortization and Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Interest Rate	0
Extended Maturity and Delay in Payments or Reduction of Interest Rate	0
Extended Maturity, Delay in Payments and Reduction of Amount	0
Extended Maturity	0
Delay in Payments or Reduction of Interest Rate	0
Total	$0

Loans_Details_6

Loans (Details 6) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	$124,204,000		$126,798,000		'
Allowance for unfunded credit commitments, beginning balance	4,075,000		9,177,000		'
Provision for credit losses	-5,804,000		-8,900,000		120,750,000
Allowance for credit losses, beginning balance	128,279,000		135,975,000		192,217,000
Transfer to (from) allowance for unfunded credit commitments	-500,000		-1,132,000		'
Net charge-offs	9,013,000		-1,204,000		176,992,000
Allowance for unfunded credit commitments, ending balance	1,716,000		4,075,000		9,177,000
Allowance for credit losses, ending balance	113,462,000		128,279,000		135,975,000
Ending Balance	111,746,000		124,204,000		126,798,000
Ending allowance balance attributable to loans:	'		'		'
Acquired and accounted for under ASC 310-30	2,232,000		4,516,000		'
Loans:	'		'		'
Individually evaluated for impairment	128,521,000		122,264,000		'
Collectively evaluated for impairment	5,327,665,000		5,173,095,000		'
Acquired and accounted for under ASC 310-30	256,365,000		471,571,000		'
Unfunded Commitments	'		'		'
Allowance for unfunded credit commitments, beginning balance	-4,075,000		-9,177,000		'
Transfer to (from) allowance for unfunded credit commitments	-500,000		-1,132,000		'
Allowance for unfunded commitments, Provision	-1,859,000		-3,970,000		'
Unfunded commitments collectively evaluated for impairment	1,027,000		576,000		'
Individually evaluated for impairment for unfunded commitments	689,000		3,499,000		'
Allowance for unfunded credit commitments, ending balance	-1,716,000		-4,075,000		-9,177,000
Allowance for credit losses	'		'		'
Allowance for credit losses, beginning balance	128,279,000		135,975,000		192,217,000
Allowance for credit losses, Charge-offs	23,675,000		30,616,000		196,780,000
Allowance for credit losses, Recoveries	14,662,000		31,820,000		19,788,000
Allowance for credit losses, Provision	-5,804,000		-8,900,000		'
Allowance for credit losses, ending balance	113,462,000		128,279,000		135,975,000
Allowance for credit losses, individually evaluated for impairment	18,057,000		20,440,000		'
Allowance for credit losses, collectively evaluated for impairment	93,173,000		103,323,000		'
Total loans	5,712,551,000	[1]	5,766,930,000	[1]	'
Commercial	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	24,943,000		21,106,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	3,706,000		2,408,000		17,571,000
Recoveries	3,156,000		3,475,000		5,370,000
Provision	-932,000		2,770,000		'
Ending Balance	23,461,000		24,943,000		21,106,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	4,284,000		3,620,000		'
Collectively evaluated for impairment	18,693,000		18,878,000		'
Acquired and accounted for under ASC 310-30	484,000		2,445,000		'
Loans:	'		'		'
Individually evaluated for impairment	17,822,000		23,886,000		'
Collectively evaluated for impairment	1,246,523,000		1,178,804,000		'
Acquired and accounted for under ASC 310-30	35,673,000	[2]	65,658,000	[2]	'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Total loans	1,300,018,000		1,268,348,000		'
Commercial collateralized by assignment of lease payments	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	7,755,000		7,561,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	0		1,721,000		1,466,000
Recoveries	1,131,000		6,720,000		225,000
Provision	273,000		-4,805,000		'
Ending Balance	9,159,000		7,755,000		7,561,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	144,000		188,000		'
Collectively evaluated for impairment	9,015,000		7,567,000		'
Acquired and accounted for under ASC 310-30	'		'		'
Loans:	'		'		'
Individually evaluated for impairment	4,461,000		1,275,000		'
Collectively evaluated for impairment	1,489,727,000		1,301,745,000		'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Total loans	1,494,188,000		1,303,020,000		'
Commercial real estate	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	61,056,000		68,695,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	7,517,000		11,377,000		96,633,000
Recoveries	6,025,000		16,987,000		3,332,000
Provision	-7,936,000		-13,249,000		'
Ending Balance	51,628,000		61,056,000		68,695,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	8,179,000		8,928,000		'
Collectively evaluated for impairment	41,763,000		50,120,000		'
Acquired and accounted for under ASC 310-30	1,686,000	[2]	2,008,000	[2]	'
Loans:	'		'		'
Individually evaluated for impairment	64,724,000		65,339,000		'
Collectively evaluated for impairment	1,582,976,000		1,696,493,000		'
Acquired and accounted for under ASC 310-30	140,504,000	[2]	247,390,000	[2]	'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Allowance for Loan Losses and Unfunded Commitments Acquired with Deteriorated Credit Quality	2,200,000		4,500,000		'
Total loans	1,788,204,000		2,009,222,000		'
Residential real estate	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	6,941,000		3,935,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	2,796,000		2,944,000		12,643,000
Recoveries	479,000		501,000		49,000
Provision	4,248,000		5,449,000		'
Ending Balance	8,872,000		6,941,000		3,935,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	3,119,000		2,858,000		'
Collectively evaluated for impairment	5,753,000		4,083,000		'
Acquired and accounted for under ASC 310-30	'	[2]	'	[2]	'
Loans:	'		'		'
Individually evaluated for impairment	16,944,000		13,276,000		'
Collectively evaluated for impairment	293,883,000		297,144,000		'
Acquired and accounted for under ASC 310-30	5,448,000	[2]	6,528,000		'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Total loans	316,275,000		316,948,000		'
Construction real estate	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	11,222,000		15,639,000		'
Transfer to (from) allowance for unfunded credit commitments	500,000		1,132,000		'
Charge-offs	980,000		4,007,000		52,917,000
Recoveries	1,616,000		2,019,000		8,590,000
Provision	-5,502,000		-3,561,000		'
Ending Balance	6,856,000		11,222,000		15,639,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	227,000		497,000		'
Collectively evaluated for impairment	6,567,000		10,662,000		'
Acquired and accounted for under ASC 310-30	62,000		63,000		'
Loans:	'		'		'
Individually evaluated for impairment	475,000		2,167,000		'
Collectively evaluated for impairment	140,778,000		108,094,000		'
Acquired and accounted for under ASC 310-30	48,313,000	[2]	118,360,000	[2]	'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	500,000		1,132,000		'
Allowance for credit losses	'		'		'
Total loans	189,566,000		228,621,000		'
Indirect vehicle	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	1,324,000		1,834,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	2,911,000		2,259,000		2,836,000
Recoveries	1,411,000		1,096,000		1,399,000
Provision	1,838,000		653,000		'
Ending Balance	1,662,000		1,324,000		1,834,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	57,000		'		'
Collectively evaluated for impairment	1,605,000		1,324,000		'
Acquired and accounted for under ASC 310-30	'		'		'
Loans:	'		'		'
Individually evaluated for impairment	123,000		'		'
Collectively evaluated for impairment	262,509,000		208,633,000		'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Total loans	262,632,000		208,633,000		'
Home equity lines	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	9,401,000		7,333,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	3,692,000		4,551,000		11,066,000
Recoveries	594,000		671,000		224,000
Provision	2,175,000		5,948,000		'
Ending Balance	8,478,000		9,401,000		7,333,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	1,358,000		850,000		'
Collectively evaluated for impairment	7,120,000		8,551,000		'
Acquired and accounted for under ASC 310-30	'		'		'
Loans:	'		'		'
Individually evaluated for impairment	23,972,000		16,321,000		'
Collectively evaluated for impairment	244,317,000		288,865,000		'
Acquired and accounted for under ASC 310-30	107,000	[2]	465,000		'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Total loans	268,396,000		305,651,000		'
Other consumer	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Beginning balance	1,562,000		695,000		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Charge-offs	2,073,000		1,349,000		1,648,000
Recoveries	250,000		351,000		599,000
Provision	1,891,000		1,865,000		'
Ending Balance	1,630,000		1,562,000		695,000
Ending allowance balance attributable to loans:	'		'		'
Individually evaluated for impairment	'		'		'
Collectively evaluated for impairment	1,630,000		1,562,000		'
Acquired and accounted for under ASC 310-30	'		'		'
Loans:	'		'		'
Individually evaluated for impairment	0		0		'
Collectively evaluated for impairment	66,952,000		93,317,000		'
Acquired and accounted for under ASC 310-30	26,320,000	[2]	33,170,000	[2]	'
Unfunded Commitments	'		'		'
Transfer to (from) allowance for unfunded credit commitments	'		'		'
Allowance for credit losses	'		'		'
Total loans	93,272,000		126,487,000		'
Purchased loans	'		'		'
Allowance for credit losses [Roll Forward]	'		'		'
Provision	2,500,000		-8,100,000		'
Net charge-offs	-218,000		4,400,000		'
Allowance for credit losses	'		'		'
Provision and charge-offs related to the number of pools	15		14		'
Total loans	$195,500,000		$261,900,000		'
[1]	Gross loan balances at December 31, 2013 and 2012 are net of unearned income, including net deferred loan fees of $1.9 million and $1.1 million, respectively.
[2]	Loans acquired in FDIC-assisted transactions and accounted for under ASC Subtopic 310-30 “Receivables — Loans and Debt Securities Acquired with Deteriorated Credit Quality.”

Loans_Details_7

Loans (Details 7) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Changes in the accretable yield for purchased credit-impaired loans	'	'
Balance at beginning of period	$5,685	$18,703
Accretion	-4,456	-13,535
Other	1,108	517
Balance at end of period	$2,337	$5,685

Loans_Details_8

Loans (Details 8) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	$235,720,000		$449,850,000
Estimated receivable amount from the FDIC under the loss-share agreement	10,544,000		'
Non covered loans	20,645,000		'
Outstanding balances on purchased loans from the FDIC	248,600,000		515,700,000
Carrying amount on loans purchased from the FDIC	235,700,000		471,600,000
Purchased Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	106,467,000		'
Estimated receivable amount from the FDIC under the loss-share agreement	570,000	[1]	'
Non covered loans	4,815,000		'
Purchased Non-Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	129,253,000		'
Estimated receivable amount from the FDIC under the loss-share agreement	9,974,000	[1]	'
Non covered loans	15,830,000		'
Commercial related	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	15,074,000		'
Non covered loans	17,032,000		'
Commercial related | Purchased Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	9,445,000	[2]	'
Non covered loans	4,726,000	[3]	'
Reimbursable Amount Covered Other Real Estate Owned	1,100,000		'
Commercial related | Purchased Non-Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	5,629,000	[2]	'
Non covered loans	12,306,000	[3]	'
Commercial	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	3,567,000		'
Commercial | Purchased Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	803,000		'
Commercial | Purchased Non-Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	2,764,000		'
Commercial real estate	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	140,504,000		'
Commercial real estate | Purchased Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	51,762,000		'
Commercial real estate | Purchased Non-Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	88,742,000		'
Construction real estate	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	48,313,000		'
Construction real estate | Purchased Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	41,928,000		'
Construction real estate | Purchased Non-Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	6,385,000		'
Other	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	28,262,000		'
Non covered loans	3,613,000		'
Other | Purchased Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	2,529,000		'
Non covered loans	89,000		'
Other | Purchased Non-Credit Impaired Loans Receivable	'		'
Purchased credit-impaired loans and non-credit-impaired loans	'		'
Covered loans	25,733,000		'
Non covered loans	$3,524,000		'
[1]	Estimated reimbursable amounts from the FDIC under the loss-share agreement exclude $1.1 million in reimbursable amounts related to covered other real estate owned.
[2]	Covered commercial related loans include commercial, commercial real estate and construction real estate loans acquired in connection with the Heritage and Benchmark FDIC-assisted transactions.
[3]	Non covered commercial related loans include commercial, commercial real estate and construction real estate for InBank.

Lease_Investments_Details

Lease Investments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Direct finance leases:	'		'
Minimum lease payments	$155,945,000		$96,834,000
Estimated unguaranteed residual values	31,272,000		32,013,000
Less: unearned income	-14,473,000		-6,995,000
Direct finance leases	172,744,000	[1]	121,852,000	[1]
Leveraged leases:	'		'
Minimum lease payments	24,320,000		28,831,000
Estimated unguaranteed residual values	2,508,000		2,714,000
Less: unearned income	-1,644,000		-2,376,000
Less: related non-recourse debt	-23,243,000		-27,319,000
Leveraged leases	1,941,000	[1]	1,850,000	[1]
Operating leases:	'		'
Equipment, at cost	218,473,000		222,083,000
Less accumulated depreciation	-87,384,000		-92,260,000
Lease investments, net	131,089,000		129,823,000
Minimum percentage of residual component in total equipment investment	10.00%		'
Loans at other banks for lease equipment purchases	$17,500,000		$21,100,000
[1]	Direct finance and leveraged leases are included as commercial loans collateralized by assignment of lease payments for financial statement purposes.

Lease_Investments_Details_2

Lease Investments (Details 2) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Minimum lease payments receivable for direct finance leases	'
2014	$62,310
2015	45,899
2016	26,814
2017	13,247
2018	5,838
Thereafter	1,837
Total	155,945
Minimum lease payments receivable for leveraged leases	'
2014	13,622
2015	7,395
2016	2,482
2017	642
2018	179
Thereafter	0
Total	24,320
Minimum lease payments receivable for operating leases	'
2014	34,839
2015	23,263
2016	13,981
2017	5,232
2018	2,011
Thereafter	421
Total	79,747
Minimum lease payments receivable for, total	'
2014	110,771
2015	76,557
2016	43,277
2017	19,121
2018	8,028
Thereafter	2,258
Total	$260,012

Lease_Investments_Details_3

Lease Investments (Details 3) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Residual values for leases by category in the year the initial lease term ends	'
2014	$26,458
2015	16,711
2016	16,605
2017	9,760
2018	4,971
Thereafter	2,263
Total	76,768
Direct Finance Leases	'
Residual values for leases by category in the year the initial lease term ends	'
2014	12,417
2015	7,427
2016	6,203
2017	2,975
2018	1,420
Thereafter	830
Total	31,272
Leveraged Leases	'
Residual values for leases by category in the year the initial lease term ends	'
2014	802
2015	974
2016	609
2017	105
2018	18
Thereafter	0
Total	2,508
Operating Leases	'
Residual values for leases by category in the year the initial lease term ends	'
2014	13,239
2015	8,310
2016	9,793
2017	6,680
2018	3,533
Thereafter	1,433
Total	$42,988

Lease_Investments_Details_4

Lease Investments (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	lease	lease
Lease Investments	'	'	'
Rental income	$62,629	$49,473	$54,859
Equipment maintenance contracts revenue, net of cost of sales	11,071	14,129	7,713
Vendor promotional income	7,587	4,051	3,191
Other lease related revenue	1,796	167	408
Gain on sale of lease payments and leased equipment, net of residual write downs	12,002	4,708	3,158
Income on lease investments, gross	95,085	72,528	69,329
Depreciation on operating leases	-33,842	-36,146	-42,390
Lease financing, net	61,243	36,382	26,939
Limit on individual lease equipment residual value per transaction	500	'	'
Number of leases	3,590	3,464	'
Average residual value per lease	21	22	'
Average residual value per master lease	$82	$79	'

Premises_and_Equipment_Details

Premises and Equipment (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Premises and Equipment	'	'	'
Premises and equipment, gross	$319,469	$305,435	'
Accumulated depreciation	-98,404	-83,902	'
Premises and equipment, net	221,065	221,533	'
Depreciation of premises and equipment	18,051	16,273	13,577
Land and land improvements	'	'	'
Premises and Equipment	'	'	'
Premises and equipment, gross	67,389	69,832	'
Buildings	'	'	'
Premises and Equipment	'	'	'
Premises and equipment, gross	98,675	97,365	'
Furniture and equipment	'	'	'
Premises and Equipment	'	'	'
Premises and equipment, gross	97,766	88,425	'
Buildings and leasehold improvements	'	'	'
Premises and Equipment	'	'	'
Premises and equipment, gross	$55,639	$49,813	'

Goodwill_and_Intangibles_Detai

Goodwill and Intangibles (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'
Carrying amount of goodwill	$423,369	$423,369	'
Weighted average amortization period (in years)	'4	'	'
Changes in the carrying amount of core deposit and client relationship intangibles	'	'	'
Balance at beginning of period	29,512	29,494	'
Amortization expense	-6,084	-5,010	-5,665
Other intangibles from business combinations	0	5,028	'
Balance at end of period	23,428	29,512	29,494
Gross carrying amount	60,292	61,429	'
Accumulated amortization	-36,864	-31,917	'
Net book value	23,428	29,512	29,494
Estimated future amortization expense	'	'	'
2014	4,748	'	'
2015	4,030	'	'
2016	3,418	'	'
2017	3,071	'	'
2018	2,812	'	'
Thereafter	5,349	'	'
Total estimated future amortization expense	$23,428	'	'

Deposits_Details

Deposits (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Deposits, by Type [Abstract]	'	'
Demand deposit accounts, noninterest bearing	$2,375,863,000	$2,164,547,000
NOW and money market accounts	2,682,419,000	2,747,273,000
Savings accounts	855,394,000	811,333,000
Certificates of deposit, $100,000 or more	827,413,000	1,020,033,000
Other certificates of deposit	640,170,000	799,511,000
Total	7,381,259,000	7,542,697,000
Brokered deposits	224,200,000	294,200,000
Scheduled maturities of time certificates	'	'
2014	1,064,248,000	'
2015	205,921,000	'
2016	64,423,000	'
2017	49,420,000	'
2018	18,739,000	'
Thereafter	64,832,000	'
Total	$1,467,583,000	'

ShortTerm_Borrowings_Details

Short-Term Borrowings (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Mar. 09, 2012	Mar. 09, 2012
			Customer repurchase agreements	Customer repurchase agreements	Federal Home Loan Bank advances	Federal Home Loan Bank advances	Line of Credit [Member]	Line of Credit [Member]
								Libor [Member]
Short-term borrowings	'	'	'	'	'	'	'	'
Weighted Average Cost	0.18%	0.42%	0.20%	0.23%	0.17%	3.58%	'	'
Amount	$493,389,000	$220,602,000	$193,389,000	$208,242,000	$300,000,000	$12,360,000	'	'
Fixed interest rate Federal Home Loan Bank advances	300,000,000	12,400,000	'	'	'	'	'	'
Effective interest rate for fixed rate advance (as a percent)	0.17%	'	'	'	'	'	'	'
Unsecured Line of Credit	'	'	'	'	'	'	$35,000,000	'
Description of interest rate basis	'	'	'	'	'	'	'one month LIBOR	'
Debt Instrument, Basis Spread on Variable Rate	'	'	'	'	'	'	'	2.00%

Longterm_Borrowings_Details

Long-term Borrowings (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Mar. 31, 2013
			Notes payable to banks	Notes payable to banks	Structured repurchase agreement	Subordinated debt facility
Long-term Debt, Unclassified [Abstract]	'	'	'	'	'	'
Federal Home Loan Bank advances	$4,300,000	$4,400,000	'	'	'	'
Effective interest rates on Federal Home Loan Bank advances, low end of range (as a percent)	3.23%	'	'	'	'	'
Effective interest rates on Federal Home Loan Bank advances, high end of range (as a percent)	5.87%	'	'	'	'	'
Long-term borrowings	'	'	'	'	'	'
Long-term borrowings	62,159,000	116,050,000	17,500,000	21,100,000	40,000,000	50,000,000
Minimum interest rates (as a percent)	'	'	2.50%	'	'	'
Maximum interest rates (as a percent)	'	'	12.00%	'	'	'
Equipment pledged as collateral	'	'	25,700,000	29,700,000	'	'
Term of structured repurchase agreement (in years)	'	'	'	'	'10 years	'
Fixed interest rate, if option not exercised (as a percent)	'	'	'	'	4.75%	'
Description of interest rate basis	'	'	'	'	'	'3-month LIBOR
Interest rate, basis spread (as a percent)	'	'	'	'	'	1.70%
Principal payments due on long-term borrowings	'	'	'	'	'	'
2014	8,974,000	'	'	'	'	'
2015	5,743,000	'	'	'	'	'
2016	42,915,000	'	'	'	'	'
2017	751,000	'	'	'	'	'
2018	180,000	'	'	'	'	'
Thereafter	3,596,000	'	'	'	'	'
Total	$62,159,000	$116,050,000	$17,500,000	$21,100,000	$40,000,000	$50,000,000

Junior_Subordinated_Notes_Issu2

Junior Subordinated Notes Issued to Capital Trusts (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
In Thousands, unless otherwise specified			Junior Subordinated Notes	Coal City Capital Trust I	MB Financial Capital Trust II	MB Financial Capital Trust III	MB Financial Capital Trust IV	MB Financial Capital Trust V	MB Financial Capital Trust VI	FOBB Statutory Trust III
			Maximum	Junior Subordinated Notes	Junior Subordinated Notes	Junior Subordinated Notes	Junior Subordinated Notes	Junior Subordinated Notes	Junior Subordinated Notes	Junior Subordinated Notes
Outstanding junior subordinated notes	'	'	'	'	'	'	'	'	'	'
Principal balance	$152,065	$152,065	'	$25,774	$36,083	$10,310	$20,619	$30,928	$23,196	$5,155
Debt Instrument, Basis Spread on Variable Rate	'	'	'	1.80%	1.40%	1.50%	1.52%	1.30%	1.30%	2.80%
Description of annual interest rate basis	'	'	'	'3-mo LIBOR	'3-mo LIBOR	'3-mo LIBOR	'3-mo LIBOR	'3-mo LIBOR	'3-mo LIBOR	'3-mo LIBOR
Period for deferment of payment of interest on notes (in years)	'	'	'5 years	'	'	'	'	'	'	'

Junior_Subordinated_Notes_Issu3

Junior Subordinated Notes Issued to Capital Trusts (Details 2) (Trust preferred securities issued by each trust, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Coal City Capital Trust I	'
Trust preferred securities issued by each trust	'
Face Value	$25,000
Debt Instrument, Basis Spread on Variable Rate	1.80%
Description of annual interest rate basis	'3-mo LIBOR
MB Financial Capital Trust II	'
Trust preferred securities issued by each trust	'
Face Value	35,000
Debt Instrument, Basis Spread on Variable Rate	1.40%
Description of annual interest rate basis	'3-mo LIBOR
MB Financial Capital Trust III	'
Trust preferred securities issued by each trust	'
Face Value	10,000
Debt Instrument, Basis Spread on Variable Rate	1.50%
Description of annual interest rate basis	'3-mo LIBOR
MB Financial Capital Trust IV	'
Trust preferred securities issued by each trust	'
Face Value	20,000
Debt Instrument, Basis Spread on Variable Rate	1.52%
Description of annual interest rate basis	'3-mo LIBOR
MB Financial Capital Trust V	'
Trust preferred securities issued by each trust	'
Face Value	30,000
Debt Instrument, Basis Spread on Variable Rate	1.30%
Description of annual interest rate basis	'3-mo LIBOR
MB Financial Capital Trust VI	'
Trust preferred securities issued by each trust	'
Face Value	22,500
Debt Instrument, Basis Spread on Variable Rate	1.30%
Description of annual interest rate basis	'3-mo LIBOR
FOBB Statutory Trust III	'
Trust preferred securities issued by each trust	'
Face Value	$5,000
Debt Instrument, Basis Spread on Variable Rate	2.80%
Description of annual interest rate basis	'3-mo LIBOR

Lease_Commitments_and_Rental_E2

Lease Commitments and Rental Expense (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Rents	'	'	'
Net rental expense	$4,700,000	$5,400,000	$5,300,000
Office space	'	'	'
Gross Rents	'	'	'
2014	5,408,000	'	'
2015	4,801,000	'	'
2016	3,810,000	'	'
2017	2,929,000	'	'
2018	2,202,000	'	'
Thereafter	16,580,000	'	'
Total	35,730,000	'	'
Sublease Rents	'	'	'
2014	926,000	'	'
2015	697,000	'	'
2016	444,000	'	'
2017	422,000	'	'
2018	414,000	'	'
Thereafter	1,005,000	'	'
Total	3,908,000	'	'
Net Rents	'	'	'
2014	4,482,000	'	'
2015	4,104,000	'	'
2016	3,366,000	'	'
2017	2,507,000	'	'
2018	1,788,000	'	'
Thereafter	15,575,000	'	'
Total	$31,822,000	'	'

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Benefit Plans	'	'	'
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%	'	'
Discretionary profit sharing contributions by company (as a percent of eligible compensation)	'	'	3.00%
Company's expected contribution to plan during current fiscal year	$7,000,000	'	'
Company's total contribution to plan	'	6,900,000	6,100,000
Deferred compensation plans	'	'	'
Defer payment, participant limit per calendar year (as a percent of compensation)	100.00%	'	'
Estimated discretionary company contributions	643,000	'	'
Actual employer's contribution	'	464,000	492,000
Chief executive officer | Non-stock deferred compensation plan.	'	'	'
Deferred Compensation Arrangement with Individual, 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	10,700,000	'	'
Decreases in fair market value of assets and obligation	$1,551,000	'	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax asset:	'	'
Allowance for credit losses	$44,418	$50,336
Federal net operating loss carryforwards	0	1,926
State net operating loss carryforwards	24,354	23,677
Other real estate owned	7,878	22,153
Stock options and restricted stock	5,816	5,808
Loans	6,833	8,628
Deferred compensation	8,423	6,129
Tax credit carryforwards	13,233	15,491
Bonus accrual	4,739	4,438
Merger and non-compete accrual	623	865
Other items	1,222	1,343
Total deferred tax asset	117,539	140,794
Valuation allowance	0	'
Total deferred tax asset, net of valuation allowance	117,539	140,794
Deferred tax liability:	'	'
Premises and equipment	-118,000	-116,780
Deferred income from FDIC-assisted transactions	-48,272	-50,565
Investment securities	-5,030	-5,573
FHLB stock dividends	-2,441	-2,774
Core deposit intangible	-2,918	-2,669
Other items	-3,799	-3,673
Total deferred tax liability	-180,460	-182,034
Net deferred tax liability	-62,921	-41,240
Net unrealized holding gain on investment securities available for sale	-5,354	-23,431
Net deferred tax liability	($68,275)	($64,671)

Income_Taxes_Details_2

Income Taxes (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current expense (benefit):	'	'	'
Federal	$12,234,000	$15,075,000	$713,000
State	5,576,000	6,225,000	-611,000
Foreign	0	0	0
Current expense (benefit)	17,810,000	21,300,000	102,000
Deferred expense	21,681,000	15,177,000	5,166,000
Income tax expense	39,491,000	36,477,000	5,268,000
Statutory federal income tax rate (as a percent)	35.00%	'	'
Federal income tax expense at expected statutory rate	48,281,000	44,398,000	15,398,000
Increase (decrease) due to:	'	'	'
Tax exempt income, net	-14,200,000	-12,539,000	-8,162,000
State tax benefit resulting from change in tax rate	0	0	-2,100,000
State tax expense net of federal impact	6,508,000	5,014,000	1,703,000
Nonincludable increase in cash surrender value of life insurance	-1,111,000	-1,177,000	-1,529,000
Nondeductible merger expense	591,000	0	0
Adjustment of tax contingency reserves	-24,000	14,000	35,000
Other items, net	-554,000	767,000	-77,000
Income tax expense	39,491,000	36,477,000	5,268,000
Federal alternative minimum tax credit carryforward [Member]	'	'	'
Operating loss carryforwards	'	'	'
Tax Credit Carryforward, Amount	12,400,000	'	'
General Business Tax Credit Carryforward [Member]	'	'	'
Operating loss carryforwards	'	'	'
Tax Credit Carryforward, Amount	700,000	'	'
State	'	'	'
Operating loss carryforwards	'	'	'
Net operating loss carryforwards	$450,700,000	'	'

Income_Taxes_Details_3

Income Taxes (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
Unrecognized Tax Benefit Without Interest	'
Balance at the beginning of the period	$95
Increases for tax positions of prior years	15
Unrecognized tax benefits recognized	-37
Balance at the end of the period	73
Interest on unrecognized Tax Benefit	'
Balance at the beginning of the period	9
Increases for tax positions of prior years	5
Unrecognized tax benefits interest on income taxes for benefits recognized	-7
Balance at the end of the period	7
Total Unrecognized Tax Benefit Including Interest	'
Balance at the beginning of the period	104
Increases for tax positions of prior years	20
Unrecognized tax benefits including interest on taxes recognized	-44
Balance at the end of the period	$80

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Commitments [Abstract]	'	'
Maximum maturity period for letters of credit (in years)	'5 years	'
Increase in maximum potential amount of future payments under letters of credit	$3,600,000	'
Dollar amount of letters of credit outstanding	70,300,000	66,700,000
Letters of credit issued or renewed	63,800,000	'
Capital expenditure commitments outstanding	2,000,000	'
Home equity lines	'	'
Commitments and contingencies	'	'
Dollar amount of line of credit outstanding	208,581,000	239,771,000
Other commitments	'	'
Commitments and contingencies	'	'
Dollar amount of line of credit outstanding	1,214,391,000	911,166,000
Standby	'	'
Commitments and contingencies	'	'
Dollar amount of line of credit outstanding	69,556,000	66,247,000
Commercial	'	'
Commitments and contingencies	'	'
Dollar amount of line of credit outstanding	$708,000	$465,000

Commitments_and_Contingencies_2

Commitments and Contingencies (Details 2) (States and political subdivisions, State of Illinois)	12 Months Ended
	Dec. 31, 2013
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	27.00%

Regulatory_Matters_Details

Regulatory Matters (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Total capital (to risk-weighted assets):	'	'
Actual Amount	$1,106,541	$1,059,357
Actual Ratio (as a percent)	16.53%	16.62%
For Capital Adequacy Purposes Amount	535,430	509,885
For Capital Adequacy Purposes Ratio (as a percent)	8.00%	8.00%
Tier I capital (to risk-weighted assets):	'	'
Actual Amount	1,022,512	939,087
Actual Ratio (as a percent)	15.28%	14.73%
For Capital Adequacy Purposes Amount	267,715	254,942
For Capital Adequacy Purposes Ratio (as a percent)	4.00%	4.00%
Tier I capital (to average assets):	'	'
Actual Amount	1,022,512	939,087
Actual Ratio (as a percent)	11.22%	10.50%
For Capital Adequacy Purposes Amount	364,587	357,906
For Capital Adequacy Purposes Ratio (as a percent)	4.00%	4.00%
MB Financial Bank	'	'
Total capital (to risk-weighted assets):	'	'
Actual Amount	974,189	983,817
Actual Ratio (as a percent)	14.59%	15.49%
For Capital Adequacy Purposes Amount	534,004	508,016
For Capital Adequacy Purposes Ratio (as a percent)	8.00%	8.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	667,505	635,021
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	10.00%	10.00%
Tier I capital (to risk-weighted assets):	'	'
Actual Amount	890,380	863,836
Actual Ratio (as a percent)	13.34%	13.60%
For Capital Adequacy Purposes Amount	267,002	254,008
For Capital Adequacy Purposes Ratio (as a percent)	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	400,503	381,012
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	6.00%	6.00%
Tier I capital (to average assets):	'	'
Actual Amount	890,380	863,836
Actual Ratio (as a percent)	9.79%	9.68%
For Capital Adequacy Purposes Amount	363,904	356,984
For Capital Adequacy Purposes Ratio (as a percent)	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$454,880	$446,230
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio (as a percent)	5.00%	5.00%

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Thousands, unless otherwise specified
Financial assets	'		'
Loans held for sale	$629		$7,492
Derivative financial instruments, assets	5,875		236
Financial liabilities	'		'
Derivative financial instrument, liabilities	12,753		28,830
Recurring basis | Total Fair Value	'		'
Financial assets	'		'
Loans held for sale	629		7,492
Assets held in trust for deferred compensation	10,679		7,746
Derivative financial instruments, assets	18,645		29,096
Financial liabilities	'		'
Other liabilities	10,569	[1]	7,746	[1]
Derivative financial instrument, liabilities	18,632		29,055
Recurring basis | Total Fair Value | U.S. Government sponsored agencies and enterprises	'		'
Financial assets	'		'
Securities available for sale	52,068		41,315
Recurring basis | Total Fair Value | States and political subdivisions	'		'
Financial assets	'		'
Securities available for sale	19,143		725,019
Recurring basis | Total Fair Value | Residential mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	701,233		939,202
Recurring basis | Total Fair Value | Commercial mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	52,941		54,126
Recurring basis | Total Fair Value | Corporate bonds	'		'
Financial assets	'		'
Securities available for sale	283,070		96,674
Recurring basis | Total Fair Value | Equity securities	'		'
Financial assets	'		'
Securities available for sale	10,457		11,835
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)	'		'
Financial assets	'		'
Securities available for sale	10,457		11,835
Loans held for sale	0		0
Assets held in trust for deferred compensation	10,679		7,746
Derivative financial instruments, assets	0		0
Financial liabilities	'		'
Other liabilities	10,569	[1]	7,746	[1]
Derivative financial instrument, liabilities	0		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Government sponsored agencies and enterprises	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | States and political subdivisions	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Residential mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Commercial mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity securities	'		'
Financial assets	'		'
Securities available for sale	10,457		11,835
Recurring basis | Significant Other Observable Inputs (Level 2)	'		'
Financial assets	'		'
Securities available for sale	1,102,599		1,850,265
Loans held for sale	629		7,492
Assets held in trust for deferred compensation	0		0
Derivative financial instruments, assets	18,645		29,096
Financial liabilities	'		'
Other liabilities	0	[1]	0	[1]
Derivative financial instrument, liabilities	18,632		29,055
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Government sponsored agencies and enterprises	'		'
Financial assets	'		'
Securities available for sale	52,068		41,315
Recurring basis | Significant Other Observable Inputs (Level 2) | States and political subdivisions	'		'
Financial assets	'		'
Securities available for sale	19,143		725,019
Recurring basis | Significant Other Observable Inputs (Level 2) | Residential mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	700,542		938,354
Recurring basis | Significant Other Observable Inputs (Level 2) | Commercial mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	52,941		54,126
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate bonds	'		'
Financial assets	'		'
Securities available for sale	277,905		91,451
Recurring basis | Significant Other Observable Inputs (Level 2) | Equity securities	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Significant Unobservable Inputs (Level 3)	'		'
Financial assets	'		'
Securities available for sale	5,856		6,071
Loans held for sale	0		0
Assets held in trust for deferred compensation	0		0
Derivative financial instruments, assets	0		0
Financial liabilities	'		'
Other liabilities	0	[1]	0	[1]
Derivative financial instrument, liabilities	0		0
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. Government sponsored agencies and enterprises	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Significant Unobservable Inputs (Level 3) | States and political subdivisions	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Significant Unobservable Inputs (Level 3) | Residential mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	691		848
Recurring basis | Significant Unobservable Inputs (Level 3) | Commercial mortgage-backed securities	'		'
Financial assets	'		'
Securities available for sale	0		0
Recurring basis | Significant Unobservable Inputs (Level 3) | Corporate bonds	'		'
Financial assets	'		'
Securities available for sale	5,165		5,223
Recurring basis | Significant Unobservable Inputs (Level 3) | Equity securities	'		'
Financial assets	'		'
Securities available for sale	$0		$0
[1]	Liabilities associated with assets held in trust for deferred compensation

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financial assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)	'	'
Balance at the beginning of the period	$6,071	$6,992
Other comprehensive income	-44	81
Principal payments	-157	-885
Balance at the end of the period	5,856	6,071
Significant Unobservable Inputs (Level 3) | Recurring basis	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Securities available for sale	5,856	6,071
Financial assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3)	'	'
Impairment charges	-14	-117
Significant Unobservable Inputs (Level 3) | Recurring basis | Residential mortgage-backed securities	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Securities available for sale	691	848
Significant Unobservable Inputs (Level 3) | Recurring basis | Corporate bonds	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Credit assumption (as a percent)	20.00%	'
Securities available for sale	$5,165	$5,223
Significant Unobservable Inputs (Level 3) | Recurring basis | Minimum | Residential mortgage-backed securities	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Constant prepayment rates (as a percent)	1.00%	'
Significant Unobservable Inputs (Level 3) | Recurring basis | Maximum | Residential mortgage-backed securities	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Constant prepayment rates (as a percent)	3.00%	'
Significant Unobservable Inputs (Level 3) | Nonrecurring basis | Minimum	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Appraisal adjustment impaired loans (as a percent)	5.00%	'
Appraisal adjustment foreclosed assets (as a percent)	5.00%	'
Significant Unobservable Inputs (Level 3) | Nonrecurring basis | Maximum	'	'
Assets measured at fair value on a nonrecurring basis	'	'
Appraisal adjustment impaired loans (as a percent)	10.00%	'
Appraisal adjustment foreclosed assets (as a percent)	10.00%	'

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financial Assets:	'	'	'
Branch impairment charges	'	$2,190	$1,594
Nonrecurring basis | Total Fair Value	'	'	'
Financial Assets:	'	'	'
Impaired loans	77,497	62,258	'
Foreclosed assets	44,601	60,228	'
Non-financial long-lived assets	'	2,314	'
Nonrecurring basis | Significant Unobservable Inputs (Level 3)	'	'	'
Financial Assets:	'	'	'
Impaired loans	77,497	62,258	'
Foreclosed assets	44,601	60,228	'
Non-financial long-lived assets	'	$2,314	'

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
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	'
Financial Assets:	'	'
Cash and due from banks	$205,193	$176,010
Interest bearing deposits with banks	268,266	111,533
Federal funds sold	42,950	0
Investment securities held to maturity	1,198,929	535,681
Non-marketable securities - FHLB and FRB stock	51,417	55,385
Loans held for sale	629	7,492
Derivative financial instruments	5,875	236
Financial Liabilities:	'	'
Non-interest bearing deposits	2,375,863	2,164,547
Interest bearing deposits	5,005,396	5,378,150
Short-term borrowings	493,389	220,602
Junior subordinated notes issued to capital trusts	152,065	152,065
Derivative financial instruments	12,753	28,830
Carrying Amount	'	'
Financial Assets:	'	'
Cash and due from banks	205,193	176,010
Interest bearing deposits with banks	268,266	111,533
Federal funds sold	42,950	'
Securities available for sale	1,118,912	1,868,171
Investment securities held to maturity	1,182,533	493,421
Non-marketable securities - FHLB and FRB stock	51,417	55,385
Loans held for sale	629	7,492
Loans, net	5,600,805	5,642,726
Accrued interest receivable	36,593	36,040
Derivative financial instruments	18,645	29,096
Financial Liabilities:	'	'
Non-interest bearing deposits	2,375,863	2,164,547
Interest bearing deposits	5,005,396	5,378,150
Short-term borrowings	493,389	220,602
Long-term borrowings	62,159	116,050
Junior subordinated notes issued to capital trusts	152,065	152,065
Accrued interest payable	2,042	2,828
Derivative financial instruments	18,632	29,055
Total Fair Value	'	'
Financial Assets:	'	'
Cash and due from banks	205,193	176,010
Interest bearing deposits with banks	268,266	111,533
Federal funds sold	42,950	'
Securities available for sale	1,118,912	1,868,171
Investment securities held to maturity	1,198,929	535,681
Non-marketable securities - FHLB and FRB stock	51,417	55,385
Loans held for sale	629	7,492
Loans, net	5,583,759	5,659,598
Accrued interest receivable	36,593	36,040
Derivative financial instruments	18,645	29,096
Financial Liabilities:	'	'
Non-interest bearing deposits	2,375,863	2,164,547
Interest bearing deposits	5,012,928	5,399,709
Short-term borrowings	493,384	220,683
Long-term borrowings	66,301	117,809
Junior subordinated notes issued to capital trusts	101,247	104,009
Accrued interest payable	2,042	2,828
Derivative financial instruments	18,632	29,055
Recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)	'	'
Financial Assets:	'	'
Cash and due from banks	205,193	176,010
Interest bearing deposits with banks	268,266	111,533
Federal funds sold	42,950	'
Securities available for sale	10,457	11,835
Investment securities held to maturity	0	0
Non-marketable securities - FHLB and FRB stock	0	0
Loans held for sale	0	0
Loans, net	0	0
Accrued interest receivable	36,593	36,040
Derivative financial instruments	0	0
Financial Liabilities:	'	'
Non-interest bearing deposits	2,375,863	2,164,547
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	2,042	2,828
Derivative financial instruments	0	0
Recurring basis | Significant Other Observable Inputs (Level 2)	'	'
Financial Assets:	'	'
Cash and due from banks	0	0
Interest bearing deposits with banks	0	0
Federal funds sold	0	'
Securities available for sale	1,102,599	1,850,265
Investment securities held to maturity	1,198,929	535,681
Non-marketable securities - FHLB and FRB stock	0	0
Loans held for sale	629	7,492
Loans, net	0	0
Accrued interest receivable	0	0
Derivative financial instruments	18,645	29,096
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	18,632	29,055
Recurring basis | Significant Unobservable Inputs (Level 3)	'	'
Financial Assets:	'	'
Cash and due from banks	0	0
Interest bearing deposits with banks	0	0
Federal funds sold	0	'
Securities available for sale	5,856	6,071
Investment securities held to maturity	0	0
Non-marketable securities - FHLB and FRB stock	51,417	55,385
Loans held for sale	0	0
Loans, net	5,583,759	5,659,598
Accrued interest receivable	0	0
Derivative financial instruments	0	0
Financial Liabilities:	'	'
Non-interest bearing deposits	0	0
Interest bearing deposits	5,012,928	5,399,709
Short-term borrowings	493,384	220,683
Long-term borrowings	66,301	117,809
Junior subordinated notes issued to capital trusts	101,247	104,009
Accrued interest payable	0	0
Derivative financial instruments	$0	$0

Stock_Incentive_Plans_Details

Stock Incentive Plans (Details) (USD $)

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Jun. 30, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Omnibus Incentive Plan (the "Omnibus Plan")

Omnibus Incentive Plan (the "Omnibus Plan")

Stock options

Stock options

Stock options

Stock options

Restricted stock and restricted stock units

Restricted stock and restricted stock units

Restricted stock and restricted stock units

Restricted stock

Performance-based restricted stock units

Performance-based restricted stock units

Market-based restricted stock

Market-based restricted stock

Market-based restricted stock

Salary Stock

Salary Stock

Minimum

Minimum

Maximum

Maximum

Director

Director

Restricted stock and restricted stock units

Performance-based restricted stock units

Restricted stock and restricted stock units

Performance-based restricted stock units

Impact of the share-based payment plans in the financial statements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total cost of share-based payment plans during the year

$5,456,000

$4,806,000

$4,836,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Amount of related income tax benefit recognized in income

2,159,000

1,918,000

1,972,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based compensation

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Intrinsic Value

'

'

'

'

'

'

'

'

'

$5,800,000

$6,200,000

$2,200,000

'

'

'

'

'

'

'

'

'

'

'

'

Number of additional authorized shares

'

'

'

'

2,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of common shares authorized for issuance

'

'

'

'

8,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Numerator of shares granted beyond threshold limit

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Denominator of shares granted beyond threshold limit

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares available for future grants

'

'

'

1,615,377

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Continuous service period for vesting of option awards (in years)

'

'

'

'

'

'4 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contractual terms of option awards (in years)

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Minimum vesting period (in years)

'

'

'

'

'

'

'

'

'5 years

'

'

'

'1 year

'3 years

'

'

'

'

'

'

'2 years

'

'4 years

'

Maximum percentage of fees with an option to be received in equity-based incentive awards

'

'

'

'

'

'

'

'

70.00%

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

'

Period of restriction for sale of underlying shares (in months)

'

'

'

'

'

'

'

'

'6 months

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding activity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding at the beginning of the period (in shares)

'

'

'

'

'

2,739,753

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Granted (in shares)

'

'

'

'

'

225,269

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exercised (in shares)

'

'

'

'

'

-381,417

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expired or cancelled (in shares)

'

'

'

'

'

-118,690

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Forfeited (in shares)

'

'

'

'

'

-21,163

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding at the end of the period (in shares)

'

'

'

'

'

2,443,752

2,739,753

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options exercisable at end of the period (in shares)

'

'

'

'

'

1,766,966

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted Average Exercise Price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding at the beginning of the period (in dollars per share)

'

'

'

'

'

$27.34

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Granted (in dollars per share)

'

'

'

'

'

$27.34

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exercised (in dollars per share)

'

'

'

'

'

$25.11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expired or cancelled (in dollars per share)

'

'

'

'

'

$31.13

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Forfeited (in dollars per share)

'

'

'

'

'

$20.04

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding at the end of the period (in dollars per share)

'

'

'

'

'

$27.57

$27.34

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options exercisable at end of the period (in dollars per share)

'

'

'

'

'

$29.93

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted Average Remaining Contractual Term (In Years)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding at the end of the period

'

'

'

'

'

'4 years 8 months 16 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options exercisable at end of the period

'

'

'

'

'

'3 years 5 months 5 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate Intrinsic Value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options outstanding at the end of the period

'

'

'

'

'

14,980,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Options exercisable at end of the period

'

'

'

'

'

7,761,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value assumptions

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Risk free interest rate (as a percent)

'

'

'

'

'

1.92%

1.02%

1.95%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected volatility of Company's stock (as a percent)

'

'

'

'

'

25.18%

27.17%

43.72%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected dividend yield (as a percent)

'

'

'

'

'

1.73%

2.00%

1.48%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected life of options (in years)

'

'

'

'

'

'5 years 6 months 19 days

'5 years 8 months 12 days

'5 years 9 months 18 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average fair value per option of options granted during the year (in dollars per share)

'

'

'

'

'

$5.88

$4.23

$7.57

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total intrinsic value of options exercised

'

'

'

'

'

1,300,000

203,000

314,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Changes in restricted shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Nonvested shares of restricted stock and nonvested restricted stock units at the beginning of the period

'

'

'

'

'

'

'

'

'

634,211

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Granted (in shares)

'

'

'

'

'

'

'

'

'

272,152

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vested (in shares)

'

'

'

'

'

'

'

'

'

-203,495

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Forfeited (in shares)

'

'

'

'

'

'

'

'

'

-17,149

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Nonvested shares of restricted stock and nonvested restricted stock units at the end of the period

'

'

'

'

'

'

'

'

'

685,719

634,211

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted Average Grant Date Fair Value, restricted shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares Outstanding at the beginning of the period (in dollars per share)

'

'

'

'

'

'

'

'

'

$18.82

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Granted (in dollars per share)

'

'

'

'

'

'

'

'

'

$26.92

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vested (in dollars per share)

'

'

'

'

'

'

'

'

'

$16.78

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Forfeited (in dollars per share)

'

'

'

'

'

'

'

'

'

$20.86

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Nonvested shares of restricted stock and nonvested restricted stock units at the end of the period (in dollars per share)

'

'

'

'

'

'

'

'

'

$22.59

$18.82

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares issued

'

'

'

'

'

'

'

'

'

'

'

'

'

56,752

65,333

92,717

66,193

'

876

14,855

'

'

'

'

Share-Based Compensation Arrangement By Share Based Payment Award, Percentage Of Shares Earned To Number Of Units Issued

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.00%

'

175.00%

Performance based restricted units performance period (in years)

'

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

Share based compensation restricted stock units multiplier (in percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

'

'

Number of consecutive trading days over which a specified closing price of the entity's stock is maintained

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'10 days

'10 days

'10 years

'

'

'

'

'

'

Minimum closing price of the entity's stock (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$27

$25.80

'

'

'

'

'

'

'

Period of restriction for sale of shares of Salary Stock (in years)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2 years

'

'

'

'

'

Weighted average issuance price of Salary Stock (in dollars per share)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$22.39

$20.10

'

'

'

'

Unrecognized compensation cost

'

'

'

$12,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Expected weighted-average period for recognition of unrecognized compensation expense (in years)

'

'

'

'2 years 8 months 12 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Derivative [Line Items]	'		'		'
Net amount payable under interest rate swap	$25,000		$30,000		'
Interest rate swap credit risk exposure	17,400,000		'		'
Asset Derivatives, Notional Amount	667,934,000		562,735,000		'
Asset Derivatives, Estimated Fair Value	18,645,000		29,096,000		'
Liability Derivatives, Notional Amount	684,999,000		559,402,000		'
Liability Derivatives, Estimated Fair Value	-18,632,000		-29,055,000		'
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]	'		'		'
Amounts of gain or (loss) recognized in income on derivatives	-90,000		178,000		36,000
Stand-alone derivative instruments	'		'		'
Derivative [Line Items]	'		'		'
Asset Derivatives, Notional Amount	667,934,000	[1]	562,735,000	[1]	'
Asset Derivatives, Estimated Fair Value	18,645,000	[1]	29,096,000	[1]	'
Liability Derivatives, Notional Amount	684,761,000	[1]	555,695,000	[1]	'
Liability Derivatives, Estimated Fair Value	-18,609,000	[1]	-28,961,000	[1]	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]	'		'		'
Amounts of gain or (loss) recognized in income on derivatives	-99,000		193,000		202,000
Commercial loan interest rate swaps	'		'		'
Derivative [Line Items]	'		'		'
Liability Derivatives, Notional Amount	238,000		'		'
Interest rate swap contracts | Derivative instruments designated as hedges of fair value	'		'		'
Derivative [Line Items]	'		'		'
Liability Derivatives, Notional Amount	238,000	[2]	3,707,000	[2]	'
Liability Derivatives, Estimated Fair Value	-23,000	[2]	-94,000	[2]	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]	'		'		'
Amounts of gain or (loss) recognized in income on derivatives	9,000		-15,000		-166,000
Interest rate swap contracts | Stand-alone derivative instruments	'		'		'
Derivative [Line Items]	'		'		'
Asset Derivatives, Notional Amount	550,883,000	[1]	460,956,000	[1]	'
Asset Derivatives, Estimated Fair Value	17,298,000	[1]	27,740,000	[1]	'
Liability Derivatives, Notional Amount	551,798,000	[1]	462,012,000	[1]	'
Liability Derivatives, Estimated Fair Value	-17,350,000	[1]	-27,832,000	[1]	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]	'		'		'
Amounts of gain or (loss) recognized in income on derivatives	40,000		30,000		163,000
Interest rate options contracts | Stand-alone derivative instruments	'		'		'
Derivative [Line Items]	'		'		'
Asset Derivatives, Notional Amount	83,907,000	[1]	70,346,000	[1]	'
Asset Derivatives, Estimated Fair Value	323,000	[1]	157,000	[1]	'
Liability Derivatives, Notional Amount	84,953,000	[1]	70,346,000	[1]	'
Liability Derivatives, Estimated Fair Value	-323,000	[1]	-157,000	[1]	'
Foreign exchange contracts | Stand-alone derivative instruments	'		'		'
Derivative [Line Items]	'		'		'
Asset Derivatives, Notional Amount	31,361,000	[1]	20,033,000	[1]	'
Asset Derivatives, Estimated Fair Value	1,006,000	[1]	1,062,000	[1]	'
Liability Derivatives, Notional Amount	47,760,000	[1]	19,337,000	[1]	'
Liability Derivatives, Estimated Fair Value	-935,000	[1]	-961,000	[1]	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]	'		'		'
Amounts of gain or (loss) recognized in income on derivatives	-30,000		67,000		8,000
Mortgage banking derivatives | Stand-alone derivative instruments	'		'		'
Derivative [Line Items]	'		'		'
Asset Derivatives, Notional Amount	1,783,000	[1]	11,400,000	[1]	'
Asset Derivatives, Estimated Fair Value	18,000	[1]	137,000	[1]	'
Liability Derivatives, Notional Amount	250,000	[1]	4,000,000	[1]	'
Liability Derivatives, Estimated Fair Value	-1,000	[1]	-11,000	[1]	'
Derivative Instruments, Gain (Loss) Recognized in Income, Net [Abstract]	'		'		'
Amounts of gain or (loss) recognized in income on derivatives	($109,000)		$96,000		$31,000
[1]	These portfolio swaps are not designated as hedging instruments under ASC Topic 815.
[2]	Hedged fixed-rate commercial real estate loans

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Financial Assets, Gross Amount Recognized	$5,875	$236
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	5,875	236
Financial Liabilities, Gross Amount Recognized	12,753	28,830
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	12,753	28,830
Repurchase Agreements, Financial Assets, Gross Amount Recognized	0	0
Repurchase Agreements, Financial Liabilities, Gross Amount Offset	0	0
Repurchase Agreements, Financial Assets, Net Amount Recognized	0	0
Repurchase Agreements, Financial Liabilities, Gross Amount Recognized	193,389	208,242
Repurchase Agreements, Financial Liabilities, Gross Amount Offset	0	0
Repurchase Agreements, Financial Liabilities, Net Amount Recognized	193,389	208,242
Total Financial Assets, Gross Amount Recognized	5,875	236
Total Financial Assets, Gross Amount Offset	0	0
Total Financial Assets, Net Amount Recognized	5,875	236
Total Financial Liabilities, Gross Amount Recognized	206,142	237,072
Total Financial Liabilities, Gross Amount Offset	0	0
Total Financial Liabilities, Net Amount Recognized	206,142	237,072
Interest rate swaps, caps and floors	'	'
Derivative [Line Items]	'	'
Financial Assets, Gross Amount Recognized	5,792	192
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	5,792	192
Financial Liabilities, Gross Amount Recognized	11,904	27,890
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	11,904	27,890
Foreign currency forward contracts	'	'
Derivative [Line Items]	'	'
Financial Assets, Gross Amount Recognized	80	43
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	80	43
Financial Liabilities, Gross Amount Recognized	848	929
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	848	929
Mortgage banking derivatives	'	'
Derivative [Line Items]	'	'
Financial Assets, Gross Amount Recognized	3	1
Financial Assets, Gross Amount Offset	0	0
Financial Assets, Net Amount Recognized	3	1
Financial Liabilities, Gross Amount Recognized	1	11
Financial Liabilities, Gross Amount Offset	0	0
Financial Liabilities, Net Amount Recognized	$1	$11

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Details 3) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Financial Assets, Net Amount Recognized	$5,875	$236
Financial Assets, Financial Instruments	-2,912	-230
Financial Assets, Collateral	0	0
Financial Assets, Net Amount	2,963	6
Financial Liabilities, Net Amount Recognized	12,753	28,830
Financial Liabilities, Financial Instruments	-2,912	-230
Financial Liabilities, Collateral	-9,786	-28,545
Financial Liabilities, Net Amount	55	55
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	193,389	208,242
Repurchase Agreements, Financial Liabilities, Financial Instruments	0	0
Repurchase Agreements, Financial Liabilities, Collateral	-193,389	-208,242
Repurchase Agreements, Financial Liabilities, Net Amount	0	0
Total Financial Assets, Net Amount Recognized	5,875	236
Total Financial Assets, Financial Instruments	-2,912	-230
Total Financial Assets, Collateral	0	0
Total Financial Assets, Net Amount	2,963	6
Total Financial Liabilities, Net Amount Recognized	206,142	237,072
Total Financial Liabilities, Financial Instruments	-2,912	-230
Total Financial Liabilities, Collateral	-203,175	-236,787
Total Financial Liabilities, Net Amount	55	55
Counterparty A [Member]	'	'
Derivative [Line Items]	'	'
Financial Assets, Net Amount Recognized	883	68
Financial Assets, Financial Instruments	-883	-68
Financial Assets, Collateral	0	0
Financial Assets, Net Amount	0	0
Financial Liabilities, Net Amount Recognized	10,669	25,497
Financial Liabilities, Financial Instruments	-883	-68
Financial Liabilities, Collateral	-9,786	-25,429
Financial Liabilities, Net Amount	0	0
Counterparty B [Member]	'	'
Derivative [Line Items]	'	'
Financial Assets, Net Amount Recognized	1,836	84
Financial Assets, Financial Instruments	-412	-84
Financial Assets, Collateral	0	0
Financial Assets, Net Amount	1,424	0
Financial Liabilities, Net Amount Recognized	412	633
Financial Liabilities, Financial Instruments	-412	-84
Financial Liabilities, Collateral	0	-549
Financial Liabilities, Net Amount	0	0
Counterparty C [Member]	'	'
Derivative [Line Items]	'	'
Financial Assets, Net Amount Recognized	2,380	36
Financial Assets, Financial Instruments	-1,612	-36
Financial Assets, Collateral	0	0
Financial Assets, Net Amount	768	0
Financial Liabilities, Net Amount Recognized	1,612	2,305
Financial Liabilities, Financial Instruments	-1,612	-36
Financial Liabilities, Collateral	0	-2,269
Financial Liabilities, Net Amount	0	0
Other Counterparties [Member]	'	'
Derivative [Line Items]	'	'
Financial Assets, Net Amount Recognized	776	48
Financial Assets, Financial Instruments	-5	-42
Financial Assets, Collateral	0	0
Financial Assets, Net Amount	771	6
Financial Liabilities, Net Amount Recognized	60	395
Financial Liabilities, Financial Instruments	-5	-42
Financial Liabilities, Collateral	0	-298
Financial Liabilities, Net Amount	$55	$55

Operating_Segments_Details

Operating Segments (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]	'	'	'
Net interest income	$272,336	$292,788	$325,273
Provision for credit losses	-5,804	-8,900	120,750
Non-interest income	154,394	129,193	122,719
Non-interest expense	294,588	304,030	283,246
Income tax expense	39,491	36,477	5,268
Net income	98,455	90,374	38,728
Total assets	9,641,427	9,571,805	9,833,072
Banking	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income	267,131	290,881	324,356
Provision for credit losses	-6,167	-9,035	120,808
Non-interest income	94,600	95,449	95,936
Non-interest expense	259,753	284,452	267,455
Income tax expense	28,201	30,780	1,182
Net income	79,944	80,133	30,847
Total assets	9,225,610	9,203,837	9,623,039
Leasing	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net interest income	5,205	1,907	917
Provision for credit losses	363	135	-58
Non-interest income	59,794	33,744	26,783
Non-interest expense	34,835	19,578	15,791
Income tax expense	11,290	5,697	4,086
Net income	18,511	10,241	7,881
Total assets	$415,817	$367,968	$210,033

Condensed_Parent_Company_Finan2

Condensed Parent Company Financial Information (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
In Thousands, unless otherwise specified
Assets	'	'	'	'
Cash	$473,459	$287,543	$244,565	$844,159
Loans	5,600,805	5,642,726	'	'
Other assets	186,154	185,151	'	'
Total assets	9,641,427	9,571,805	9,833,072	'
LIABILITIES AND STOCKHOLDERS’ EQUITY	'	'	'	'
Junior subordinated notes issued to capital trusts	152,065	152,065	'	'
Other liabilities	225,873	264,621	'	'
Stockholders’ equity	1,326,682	1,275,770	1,393,027	1,344,786
Total liabilities and stockholders’ equity	9,641,427	9,571,805	'	'
MB Financial, Inc.	'	'	'	'
Assets	'	'	'	'
Cash	122,001	57,303	108,323	90,152
Loans	0	6,960	'	'
Investments in subsidiaries	1,340,641	1,346,590	'	'
Other assets	24,505	21,796	'	'
Total assets	1,487,147	1,432,649	'	'
LIABILITIES AND STOCKHOLDERS’ EQUITY	'	'	'	'
Junior subordinated notes issued to capital trusts	152,065	152,065	'	'
Other liabilities	8,400	4,814	'	'
Stockholders’ equity	1,326,682	1,275,770	'	'
Total liabilities and stockholders’ equity	$1,487,147	$1,432,649	'	'

Condensed_Parent_Company_Finan3

Condensed Parent Company Financial Information (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Parent Company Financial Information	'	'	'
Income before income taxes	$137,946	$126,851	$43,996
Income tax benefit	39,491	36,477	5,268
Net income	98,455	90,374	38,728
Dividends and discount accretion on preferred shares	'	3,269	10,414
Net income available to common stockholders	98,455	87,105	28,314
MB Financial, Inc.	'	'	'
Condensed Parent Company Financial Information	'	'	'
Dividends from subsidiaries	80,500	146,000	0
Interest and other income	4,215	1,682	3,410
Interest and other expense	7,143	7,117	6,248
Income before income taxes	77,572	140,565	-2,838
Income tax benefit	-1,223	-2,192	-1,151
Income (loss) before equity in undistributed net income of subsidiaries	78,795	142,757	-1,687
Equity in undistributed net income (loss) of subsidiaries	19,660	-52,383	40,415
Net income	98,455	90,374	38,728
Dividends and discount accretion on preferred shares	0	3,269	10,414
Net income available to common stockholders	$98,455	$87,105	$28,314

Condensed_Parent_Company_Finan4

Condensed Parent Company Financial Information (Details 3) (USD $)	0 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 14, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities	'	'	'	'
Net income	'	$98,455	$90,374	$38,728
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Amortization of restricted stock awards	'	4,280	3,544	3,277
Compensation expense for stock option grants	'	1,176	1,262	1,559
Cash Flows From Investing Activities	'	'	'	'
Net decrease in loans	'	38,725	219,125	189,630
Net cash (used in) provided by investing activities	'	-39,247	330,163	-287,863
Cash Flows From Financing Activities	'	'	'	'
Treasury stock transactions, net	'	-1,672	-249	-1,149
Stock options exercised	'	1,014	154	1,903
Excess tax benefits from share-based payment arrangements	'	-325	-390	-53
Dividends paid on common stock	'	-24,070	-7,101	-2,164
Dividends paid on preferred stock	'	'	-3,239	-9,799
Repurchase of preferred stock and warrant	-196,000	'	'	'
Net cash provided by (used in) financing activities	'	32,405	-469,005	-584,312
Net increase (decrease) in cash and cash equivalents	'	185,916	42,978	-599,594
Cash:	'	'	'	'
Beginning of year	'	287,543	244,565	844,159
End of year	'	473,459	287,543	244,565
MB Financial, Inc.	'	'	'	'
Cash Flows From Operating Activities	'	'	'	'
Net income	'	98,455	90,374	38,728
Adjustments to reconcile net income to net cash provided by operating activities:	'	'	'	'
Amortization of restricted stock awards	'	4,280	3,544	3,277
Compensation expense for stock option grants	'	1,176	1,262	1,559
Equity in undistributed net income of subsidiaries	'	-19,660	52,383	-40,415
Change in other assets and other liabilities	'	-1,460	-5,064	8,275
Net cash provided by operating activities	'	82,791	142,499	11,424
Cash Flows From Investing Activities	'	'	'	'
Net decrease in loans	'	6,960	21,010	18,009
Net cash (used in) provided by investing activities	'	6,960	21,010	18,009
Cash Flows From Financing Activities	'	'	'	'
Treasury stock transactions, net	'	-1,672	-249	-1,149
Stock options exercised	'	1,014	154	1,903
Excess tax benefits from share-based payment arrangements	'	-325	-390	-53
Dividends paid on common stock	'	-24,070	-7,101	-2,164
Dividends paid on preferred stock	'	0	-3,239	-9,799
Repurchase of preferred stock and warrant	'	0	-197,518	0
Redemption of on junior subordinated notes issued to capital trusts	'	0	-6,186	0
Net cash provided by (used in) financing activities	'	-25,053	-214,529	-11,262
Net increase (decrease) in cash and cash equivalents	'	64,698	-51,020	18,171
Cash:	'	'	'	'
Beginning of year	'	57,303	108,323	90,152
End of year	'	$122,001	$57,303	$108,323

Preferred_Stock_Details

Preferred Stock (Details) (USD $)	0 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	2-May-12	Mar. 14, 2012	Sep. 30, 2009	Dec. 31, 2013	Sep. 30, 2009	Dec. 31, 2013	Sep. 17, 2009
				Series A Preferred Stock	Common Stock	Common Stock	Common Stock
Common and preferred stock	'	'	'	'	'	'	'
Series A Preferred Stock, cumulative dividends rate for the first five years (as a percent)	'	'	'	5.00%	'	'	'
Series A Preferred Stock, cumulative dividends rate after five years (as a percent)	'	'	'	9.00%	'	'	'
Warrants, term (in years)	'	'	'	'	'	'10 years	'
Warrants to purchase the Company's common stock, initially authorized (in shares)	'	'	'	'	'	'	1,012,048
Warrants to purchase the Company's common stock, as adjusted (in shares)	'	'	'	'	'	'	506,024
Warrants, exercise price (in dollars per share)	'	'	'	'	'	'	29.05
Common stock issued (in shares)	'	'	'	'	12,578,125	'	'
Gross proceeds from public offering of common stock	'	'	'	'	$201,300,000	'	'
Proceeds from public offering of common stock, net of underwriting discounts, commissions and offering expenses	'	'	'	'	190,900,000	'	'
Aggregate gross proceeds from "Qualified Equity Offerings"	'	'	196,000,000	'	'	'	'
Percentage of reduction in number of common shares to be purchased under the warrant	'	'	'	'	'	'	50.00%
Payments for repurchase of preferred stock and preference stock	'	196,000,000	'	'	'	'	'
Payments for repurchase of warrants	$1,500,000	'	'	'	'	'	'