Goodwill and Other Intangible Assets (Details Textual) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended	0 Months Ended		3 Months Ended	9 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Core Deposits	Apr. 12, 2013 Citizens Republic Bancorp		Sep. 30, 2013 Citizens Republic Bancorp	Sep. 30, 2013 Citizens Republic Bancorp Core Deposits	Apr. 12, 2013 Citizens Republic Bancorp Core Deposits		Sep. 30, 2013 Citizens Republic Bancorp Customer Relationships		Apr. 12, 2013 Citizens Republic Bancorp Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets							$ 84,774,000	[1]			$ 70,800,000	[1]	$ 14,000,000	[1]	$ 14,000,000	[1]
Goodwill	734,883,000	460,044,000	734,883,000	460,044,000	460,044,000
Finite-Lived Intangible Asset, Useful Life						10 years				15 years			12 years
Amortization of Intangible Assets	2,972,000	456,000	5,700,000	1,422,000
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	2,700,000		2,700,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	11,700,000		11,700,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	10,400,000		10,400,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	9,200,000		9,200,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	8,200,000		8,200,000
Goodwill							$ 274,838,000		$ 500,000

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