Goodwill and Other Intangible Assets Intangible Assets Schedule (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2013 Core Deposits	Dec. 31, 2012 Core Deposits	Sep. 30, 2012 Core Deposits	Sep. 30, 2013 Noncompete Agreement	Dec. 31, 2012 Noncompete Agreement	Sep. 30, 2012 Noncompete Agreement	Sep. 30, 2013 Lease Agreements	Dec. 31, 2012 Lease Agreements	Sep. 30, 2012 Lease Agreements	Apr. 12, 2013 Citizens Republic Bancorp		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]
Finite-Lived Intangible Assets, Net	$ 85,447	$ 6,373	$ 6,817	$ 73,208	$ 6,213	$ 6,642	$ 6	$ 26	$ 32	$ 107	$ 134	$ 143					$ 12,126
Intangible assets													84,774	[1]	70,800	[1]	14,000	[1]	14,000	[1]
Finite-Lived Intangible Assets, Gross	102,253	17,479	17,479	87,533	16,759	16,759	102	102	102	618	618	618
Finite-Lived Intangible Assets, Accumulated Amortization	$ (16,806)	$ (11,106)	$ (10,662)	$ (14,325)	$ (10,546)	$ (10,117)	$ (96)	$ (76)	$ (70)	$ (511)	$ (484)	$ (475)					$ (1,874)

[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.