Loans Changes in the Carrying Amount and Accretable Yield for Covered Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended						3 Months Ended		6 Months Ended
	Jun. 30, 2014 Covered impaired loan [Member]	Jun. 30, 2013 Covered impaired loan [Member]	Jun. 30, 2014 Covered impaired loan [Member]	Jun. 30, 2013 Covered impaired loan [Member]	Mar. 31, 2014 Covered impaired loan [Member]	Dec. 31, 2013 Covered impaired loan [Member]	Mar. 31, 2013 Covered impaired loan [Member]	Dec. 31, 2012 Covered impaired loan [Member]	Jun. 30, 2014 Acquired Impaired Loans	Jun. 30, 2013 Acquired Impaired Loans	Jun. 30, 2014 Acquired Impaired Loans	Jun. 30, 2013 Acquired Impaired Loans	Mar. 31, 2014 Acquired Impaired Loans	Dec. 31, 2013 Acquired Impaired Loans	Mar. 31, 2013 Acquired Impaired Loans	Dec. 31, 2012 Acquired Impaired Loans	Jun. 30, 2014 Citizens Republic Bancorp Acquired Impaired Loans	Apr. 12, 2013 Citizens Republic Bancorp Acquired Impaired Loans
Changes in the carrying amount of accretable yield for covered loans [Line Items]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield	$ 53,655	$ 81,758	$ 53,655	$ 81,758	$ 63,003	$ 67,282	$ 102,130	$ 113,288	$ 137,442	$ 120,067	$ 137,442	$ 120,067	$ 142,284	$ 136,646	$ 0	$ 0	$ 0	$ 131,558
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	316,481	537,257	316,481	537,257	364,488	403,692	656,670	762,386	519,250	752,682	519,250	752,682	557,199	601,000	0	0	0	819,715
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion	(12,139)	(17,757)	(24,755)	(37,271)					12,746	(9,090)	24,487	9,090
Certain Loans Acquired in Transfer not Accounted for as Debt Securities Carrying Amount Accretion	12,139	17,757	24,755	37,271					12,746	9,090	24,487	9,090
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications from Nonaccretable Difference	5,549	5,413	11,606	15,982					10,499	0	30,013	0
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities F D I C Payments Received under Loss Sharing Agreement	(60,146)	(137,170)	(111,966)	(262,400)					50,695	(76,123)	106,237	76,123
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans	$ (2,758)	$ (8,027)	$ (478)	$ (10,241)					$ 2,595	$ (2,401)	$ 4,730	$ 2,401