Shareholders' Equity And Earnings Per Share (Narrative) (Details) (USD $)	0 Months Ended		1 Months Ended		3 Months Ended	9 Months Ended		12 Months Ended	9 Months Ended	3 Months Ended	12 Months Ended					12 Months Ended				1 Months Ended
	Mar. 15, 2011	Dec. 19, 2008	Aug. 31, 2011	Aug. 31, 2008	Dec. 31, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Sep. 30, 2011 Equity Component [Member]	Mar. 31, 2010 Common Stock [Member]	Dec. 31, 2010 Common Stock Offering Additional Series [Member]	Sep. 30, 2011 Series A Preferred Stock [Member]	Dec. 31, 2010 Series A Preferred Stock [Member]	Sep. 30, 2010 Series A Preferred Stock [Member]	Aug. 31, 2008 Series A Preferred Stock [Member]	Dec. 31, 2010 Series B Preferred Stock [Member]	Sep. 30, 2011 Series B Preferred Stock [Member]	Sep. 30, 2010 Series B Preferred Stock [Member]	Dec. 19, 2008 Series B Preferred Stock [Member]	Jul. 31, 2011 Great Lakes Advisors, Inc [Member]	Jul. 31, 2011 Elgin State Bancorp, Inc [Member]
Common stock, shares issued					$ 34,864,000	$ 35,926,000	$ 31,145,000	$ 34,864,000		$ 6,700,000	$ 3,700,000
Sale of stock, price per share										$ 33.25	$ 30.00
Net proceeds from issuance of common stock							210,417,000			210,300,000	104,800,000
Tangible equity units sold					4,600,000			4,600,000
Percentage of tangible equity units sold					7.50%			7.50%
Tangible equity unit public offering price per unit					50.00			50.00
Tangible equity unit, quarterly cash payments								222,700,000
Percentage of fair value of debt component quarterly cash payments						7.50%
Debt component maturity date						Dec. 15, 2013
Discount rate on debt component						9.50%
Risk-free rate			1.10%			1.20%	2.70%		0.95%
Expected stock price volatility minimum									35.00%
Expected stock price volatility maximum									(45.00%)
Percent of dividend yield plus stock borrow cost									0.85%
Equity term, years			4.4			6.1	6.2		3.02
Junior subordinated amortizing note, initial principal amount						9.728182
Junior subordinated amortizing note, bearing interest						9.50%
Junior subordinated amortizing note, scheduled final installment payment date						Dec. 15, 2013
Quarterly Installments on Amortizing Note	(0.989583)					0.9375
Extended installment period on amortizing note						Dec. 15, 2015
Non-cumulative perpetual convertible preferred stock, issued				50,000
Preferred stock, liquidation value												$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 1,000	$ 1,000
Liquidation of preference shares, private transactions				50,000,000
Preferred stock, dividend rate, percentage				8.00%
Preferred Stock is convertible into common stock, option of holder at a conversion rate				$ 38.88
Treasury issued under capital purchase program		250,000,000
Preferred stock repurchase price, including accrued and unpaid dividends																251,300,000
Accrued and unpaid dividends																1,300,000
Reduction in non-cash deemed preferred stock dividend					$ 11,400,000
Cumulative perpetual convertible preferred stocks, issued		250,000
Warrant to purchase of shares		1,643,295
Exercise price of common stock, per share		$ 22.82
Warrant termination period, years		10
Preferred stock, cumulative dividend coupon rate		5.00%
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares																				529,087	353,650
Warrants holders common stock purchase price per share						$ 30.50
Warrants outstanding					19,000	19,000		19,000
Warrants expiration date						Feb. 01, 2013