Shareholders' Equity (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended				1 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended	1 Months Ended	0 Months Ended			1 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Jul. 19, 2013	Aug. 31, 2008	Mar. 31, 2012	May 01, 2013	Dec. 31, 2012	Jul. 02, 2011	Aug. 30, 2012	Mar. 15, 2011	Dec. 15, 2013	Dec. 19, 2008	Feb. 28, 2013	Feb. 28, 2013	Feb. 28, 2015	Jan. 31, 2015	Dec. 07, 2010
Shareholders' Equity [Line Items]
Tangible equity units sold (in shares)																											4,600,000
Percentage of tangible equity units sold																											7.50%
Tangible equity unit public offering price per unit (in usd per share)																											$ 50.00
Tangible equity unit, net proceeds												$ 222,700,000
Debt Instrument, Frequency of Periodic Payment											annual
Preferred Stock, Shares Issued	126,467				126,477				126,467	126,477
Preferred stock, liquidation value (in usd per share)	$ 1,000				$ 1,000				$ 1,000	$ 1,000
Preferred Stock, Value, Issued	126,467,000				126,477,000				126,467,000	126,477,000
Common Stock, No Par Value	$ 0				$ 0				$ 0	$ 0			0
Cash dividends declared per common share	$ 0.10	$ 0.10	$ 0.10	$ 0.10	$ 0	$ 0.09	$ 0	$ 0.09	$ 0.40	$ 0.18	$ 0.18
Series A Preferred Stock [Member]
Shareholders' Equity [Line Items]
Preferred Stock, Shares Issued														50,000
Preferred stock, liquidation value (in usd per share)														$ 1,000
Preferred Stock, Value, Issued														50,000,000
Preferred Stock, Dividend Payment Terms														quarterly
Preferred stock, dividend rate, percentage														8.00%
Convertible Preferred Stock, Terms of Conversion														38.88
Preferred Stock, Shares Converted													50,000
Convertible Preferred Stock, Shares Issued upon Conversion													1,944,000
Series C Preferred Stock [Member]
Shareholders' Equity [Line Items]
Preferred Stock, Shares Issued	126,467				126,477				126,467	126,477					126,500
Preferred stock, liquidation value (in usd per share)															$ 1,000
Preferred Stock, Value, Issued															126,500,000
Preferred Stock, Dividend Payment Terms															quarterly
Preferred stock, dividend rate, percentage															5.00%
Convertible Preferred Stock, Terms of Conversion															24.3132
Preferred Stock, Shares Converted									10	23
Convertible Preferred Stock, Shares Issued upon Conversion	244				558				244	558
First Lansing Bancorp, Inc. [Member]
Shareholders' Equity [Line Items]
Shares issued in acquisitions																648,286
Hyde Park Bank and Trust [Member] [Member]
Shareholders' Equity [Line Items]
Shares issued in acquisitions																	372,530
Great Lakes Advisors [Member]
Shareholders' Equity [Line Items]
Shares issued in acquisitions																		529,087	25,493
Junior Subordinated Amortizing Notes [Member]
Shareholders' Equity [Line Items]
Debt Instrument, Maturity Date										Dec. 15, 2013		Dec. 15, 2013
Debt Instrument, Frequency of Periodic Payment										quarterly
Debt Instrument, Interest Rate, Stated Percentage																					9.50%
Debt [Member] | Junior Subordinated Amortizing Notes [Member]
Shareholders' Equity [Line Items]
Debt Instrument, Maturity Date												Dec. 15, 2013
Debt Instrument, Frequency of Periodic Payment												quarterly
Percentage of fair value of debt component quarterly cash payments												7.50%
Discount rate on debt component																											9.50%
Junior subordinated amortizing note, initial principal amount																											9.728182
Debt Instrument, Interest Rate, Stated Percentage																											9.50%
Quarterly installments on amortizing note												$ 0.9375								$ 0.989583
Equity [Member]
Shareholders' Equity [Line Items]
Debt Instrument, Maturity Date												Dec. 15, 2013
Fair Value Assumptions, Risk Free Interest Rate												0.95%
Percent of dividend yield plus stock borrow cost												0.85%
Fair Value Assumptions, Expected Term												3 years 0 months 7 days
Settlement rate																					1.3333
Number of consecutive trading days																					20 days
Amount Per Share Reclassified From Surplus To Common Stock																					$ 1.00
Minimum [Member] | Equity [Member]
Shareholders' Equity [Line Items]
Fair Value Assumptions, Expected Volatility Rate												35.00%
Maximum [Member] | Equity [Member]
Shareholders' Equity [Line Items]
Fair Value Assumptions, Expected Volatility Rate												45.00%
US Treasury [Member]
Shareholders' Equity [Line Items]
Warrants outstanding (in shares)	937,417								937,417													1,643,295
Exercise price of common stock (in usd per share)																						$ 22.82
Warrant termination period																						10 years
Warrants exercised (in shares)									705,878
Common Stock, Shares, Issued from Exercise of Warrant Shares									363,155
Other Warrants [Member]
Shareholders' Equity [Line Items]
Warrants outstanding (in shares)	0				0				0	0					19,000
Exercise price of common stock (in usd per share)																								$ 30.50
Warrants exercised (in shares)															18,000								1,000
Subsequent Event [Member]
Shareholders' Equity [Line Items]
Cash dividends declared per common share																										$ 0.11
Common Stock Dividends Per Share Declared Annualized (in usd per share)																										$ 0.44
Dividends Payable, Date to be Paid																									Feb. 19, 2015
Dividends Payable, Date of Record																									Feb. 05, 2015