Mortgage Servicing Rights and Mortgage Servicing Activity-Changes in the carrying amount of mortgage servicing rights (Details) (USD $)	3 Months Ended			9 Months Ended			12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013		Sep. 30, 2014 Fair Value, Inputs, Level 3	Dec. 31, 2013 Fair Value, Inputs, Level 3	Sep. 30, 2013 Fair Value, Inputs, Level 3	Sep. 30, 2014 Citizens Republic Bancorp	Sep. 30, 2014 Mortgage Servicing Rights [Member] Citizens Republic Bancorp	Apr. 12, 2013 Mortgage Servicing Rights [Member] Citizens Republic Bancorp	Sep. 30, 2014 Residential Mortgages	Sep. 30, 2013 Residential Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor Servicing Assets or Liabilities Impact of Twenty Five Percent Adverse Change in Prepayment Speed	$ 1,813,000			$ 1,813,000
Servicing Asset															2,600,000,000	2,700,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets														1,065,000
Mortage Servicing Rights Amortized Value [Roll Forward]
Mortgage Servicing Rights Beginning of Period	22,150,000		22,604,000	22,760,000		21,316,000	21,316,000					0	0	0
Mortgage Servicing Rights Additions	1,035,000		1,450,000	2,242,000		4,151,000
Amortization of Mortgage Servicing Rights (MSRs)	996,000		(1,131,000)	2,813,000		(3,609,000)
Mortgage Servicing Rights, End of Period	22,189,000		22,923,000	22,189,000		22,923,000	22,760,000					0	0	0
Mortage Servicing Rights Valuation Rollforward [Roll Forward]
Mortgage Servicing rights Valuation Allowance Beginning of Period	562,000		482,000	282,000		(2,564,000)	(2,564,000)
Mortgage Servicing Rights (MSR) Impairment (Recovery)	57,000		(90,000)	(223,000)		(1,992,000)	2,300,000
Mortgage Servicing rights Valuation Allowance, End of Period	505,000		(572,000)	505,000		(572,000)	282,000
Mortgage Servicing Rights Net Carrying balance	21,684,000		22,351,000	21,684,000		22,351,000	22,500,000
Fair Value of Mortgage Servicing Rights	$ 22,229,000	[1]	$ 22,616,000	$ 22,229,000	[1]	$ 22,616,000	$ 23,041,000	[1]	$ 22,229,000	$ 23,041,000	$ 22,616,000

[1] (b) - MSRs with a recorded investment of $22.2 million were reduced by a specific valuation allowance totaling $0.5 million to a reported carrying value of $21.7 million resulting in recognition of $0.1 million in recoveries included in loans sales and servicing income in the three months ended September 30, 2014.