Business Combinations Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	6 Months Ended		3 Months Ended				6 Months Ended							6 Months Ended
	Apr. 12, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Citizens Republic Bancorp	Jun. 30, 2013 Citizens Republic Bancorp	Apr. 12, 2013 Citizens Republic Bancorp		Jun. 30, 2014 Core Deposits	Jun. 30, 2014 Core Deposits Citizens Republic Bancorp	Apr. 12, 2013 Core Deposits Citizens Republic Bancorp		Jun. 30, 2014 Customer Relationships	Dec. 31, 2013 Customer Relationships	Jun. 30, 2013 Customer Relationships	Jun. 30, 2014 Customer Relationships Citizens Republic Bancorp	Apr. 12, 2013 Customer Relationships Citizens Republic Bancorp
Business Acquisition [Line Items]
Stock issued for Citizens acquisition					55,468,283	55,468,283
Business Acquisition, Share Price						$ 16.68
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable		$ 925,211
Sale to the Treasury of Newly issued Non-Voting Preferred Shares Part of TARP						355,371
Cash paid in lieu of stock to Citizens stockholders at acquisition						61
Adjustments to Additional Paid in Capital, Warrant Issued	3,000	0	3,000
Business Combination, Consideration Transferred					1,283,643
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents						544,380
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Marketable Securities						3,202,575
Business Combination, Acquired Receivables, Fair Value						4,617,004
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment						138,536
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles						84,774	[1]			70,800	[1]	14,000	14,000	14,000		14,000	[1]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets						681,100
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets						9,268,369
Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Deposits						7,276,754
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Long-term Debt						908,824
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other						80,842
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities						8,266,420
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net						1,001,949
Goodwill				$ 281,694
Finite-Lived Intangible Asset, Useful Life								10 years	15 years						12 years

[1] Intangible assets consist of core deposit intangibles of $70.8 million and trust relationships of approximately $14.0 million. The useful lives for which the core deposit intangibles and the trust relationships are being amortized over is 15 years and 12 years, respectively.