Consolidated Statements Of Condition (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and due from banks	$ 225,136us-gaap_CashAndDueFromBanks	$ 253,408us-gaap_CashAndDueFromBanks
Federal funds sold and securities purchased under resale agreements	5,571	10,456
Interest bearing deposits with banks	998,437us-gaap_InterestBearingDepositsInBanks	495,574us-gaap_InterestBearingDepositsInBanks
Available-for-sale securities, at fair value	1,792,078us-gaap_AvailableForSaleSecurities	2,176,290us-gaap_AvailableForSaleSecurities
Trading account securities	1,206us-gaap_TradingSecurities	497us-gaap_TradingSecurities
Federal Home Loan Bank and Federal Reserve Bank stock	91,582	79,261
Brokerage customer receivables	24,221	30,953
Mortgage loans held-for-sale	351,290	334,327
Loans, net of unearned income, excluding covered loans	14,409,398	12,896,602
Covered loans	226,709	346,431
Total loans	14,636,107	13,243,033
Less: Allowance for loan losses	91,705	96,922
Less: Allowance for covered loan losses	2,131	10,092
Net loans	14,542,271	13,136,019
Premises and equipment, net	555,228us-gaap_PropertyPlantAndEquipmentNet	531,947us-gaap_PropertyPlantAndEquipmentNet
FDIC indemnification asset	11,846us-gaap_FDICIndemnificationAsset	85,672us-gaap_FDICIndemnificationAsset
Accrued interest receivable and other assets	501,882	569,619
Trade date securities receivable	485,534wtfc_TradeDateSecuritiesReceivable	0wtfc_TradeDateSecuritiesReceivable
Goodwill	405,634us-gaap_Goodwill	374,547us-gaap_Goodwill
Other intangible assets	18,811	19,213
Total assets	20,010,727us-gaap_Assets	18,097,783us-gaap_Assets
Deposits:
Non-interest bearing	3,518,685	2,721,771
Interest bearing	12,763,159	11,947,018
Total deposits	16,281,844us-gaap_Deposits	14,668,789us-gaap_Deposits
Federal Home Loan Bank advances	733,050	417,762
Other borrowings	196,465us-gaap_OtherBorrowings	255,104us-gaap_OtherBorrowings
Subordinated notes	140,000us-gaap_SubordinatedDebt	0us-gaap_SubordinatedDebt
Junior subordinated debentures	249,493	249,493
Trade date securities payable	3,828wtfc_TradeDateSecuritiesPayable	303,088wtfc_TradeDateSecuritiesPayable
Accrued interest payable and other liabilities	336,225	302,958
Total liabilities	17,940,905us-gaap_Liabilities	16,197,194us-gaap_Liabilities
Preferred stock, no par value; 20,000,000 shares authorized:
Series C - $1,000 liquidation value; 126,467 and 126,477 shares issued and outstanding at December 31, 2014 and 2013, respectively	126,467us-gaap_PreferredStockValue	126,477us-gaap_PreferredStockValue
Common stock, no par value; $1.00 stated value; 100,000,000 shares authorized at December 31, 2014 and 2013; 46,881,108 shares issued at December 31, 2014 and 46,181,588 shares issued at December 31, 2013	46,881us-gaap_CommonStockValue	46,181us-gaap_CommonStockValue
Surplus	1,133,955us-gaap_AdditionalPaidInCapital	1,117,032us-gaap_AdditionalPaidInCapital
Treasury stock, at cost, 76,053 shares issued at December 31, 2014 and 65,005 shares at December 31, 2013	(3,549)us-gaap_TreasuryStockValue	(3,000)us-gaap_TreasuryStockValue
Retained earnings	803,400	676,935
Accumulated other comprehensive loss	(37,332)	(63,036)
Total shareholders' equity	2,069,822us-gaap_StockholdersEquity	1,900,589us-gaap_StockholdersEquity
Total liabilities and shareholders' equity	$ 20,010,727	$ 18,097,783

Sum of the carrying values as of the balance sheet date of liabilities incurred and payable to vendors for goods and services received, and other costs not separately disclosed in the balance sheet that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered.

No definition available.