Benefit Plans (Schedule of Assumptions Used) (Details)	12 Months Ended																								12 Months Ended						0 Months Ended	12 Months Ended																					12 Months Ended
	Dec. 31, 2013 Beginning of year [Member] Prescription Drugs	Dec. 31, 2012 Beginning of year [Member] Prescription Drugs	Dec. 31, 2011 Beginning of year [Member] Prescription Drugs	Dec. 31, 2013 Beginning of year [Member] Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent		Dec. 31, 2012 Beginning of year [Member] Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent		Dec. 31, 2011 Beginning of year [Member] Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent		Dec. 31, 2013 Beginning of year [Member] Pension Benefits		Dec. 31, 2012 Beginning of year [Member] Pension Benefits		Dec. 31, 2011 Beginning of year [Member] Pension Benefits		Dec. 31, 2013 Beginning of year [Member] Postretirement Benefits	Dec. 31, 2012 Beginning of year [Member] Postretirement Benefits	Dec. 31, 2011 Beginning of year [Member] Postretirement Benefits	Dec. 31, 2013 Beginning of year [Member] Defined Benefit Postretirement Life Insurance [Member]	Dec. 31, 2012 Beginning of year [Member] Defined Benefit Postretirement Life Insurance [Member]	Dec. 31, 2011 Beginning of year [Member] Defined Benefit Postretirement Life Insurance [Member]	Dec. 31, 2013 Beginning of year [Member] Supplemental Executive Retirement Nonqualified Pension Plan	Dec. 31, 2012 Beginning of year [Member] Supplemental Executive Retirement Nonqualified Pension Plan	Dec. 31, 2011 Beginning of year [Member] Supplemental Executive Retirement Nonqualified Pension Plan	Dec. 31, 2013 Beginning of year [Member] Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent		Dec. 31, 2012 Beginning of year [Member] Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent		Dec. 31, 2011 Beginning of year [Member] Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent		Apr. 12, 2013 Beginning of year [Member] Citizens Republic Bancorp Pension Benefits	Dec. 31, 2013 End of year [Member] Prescription Drugs	Dec. 31, 2012 End of year [Member] Prescription Drugs	Dec. 31, 2011 End of year [Member] Prescription Drugs	Dec. 31, 2013 End of year [Member] Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent		Dec. 31, 2012 End of year [Member] Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent		Dec. 31, 2011 End of year [Member] Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent		Dec. 31, 2013 End of year [Member] Pension Benefits	Dec. 31, 2012 End of year [Member] Pension Benefits	Dec. 31, 2011 End of year [Member] Pension Benefits	Dec. 31, 2013 End of year [Member] Postretirement Benefits	Dec. 31, 2012 End of year [Member] Postretirement Benefits	Dec. 31, 2011 End of year [Member] Postretirement Benefits	Dec. 31, 2013 End of year [Member] Defined Benefit Postretirement Life Insurance [Member]	Dec. 31, 2012 End of year [Member] Defined Benefit Postretirement Life Insurance [Member]	Dec. 31, 2011 End of year [Member] Defined Benefit Postretirement Life Insurance [Member]	Dec. 31, 2013 End of year [Member] Supplemental Executive Retirement Nonqualified Pension Plan	Dec. 31, 2012 End of year [Member] Supplemental Executive Retirement Nonqualified Pension Plan	Dec. 31, 2011 End of year [Member] Supplemental Executive Retirement Nonqualified Pension Plan	Dec. 31, 2013 End of year [Member] Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent		Dec. 31, 2012 End of year [Member] Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent		Dec. 31, 2011 End of year [Member] Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent		Dec. 31, 2013 End of year [Member] Citizens Republic Bancorp Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase												5.22%		5.22%																													5.22%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate										4.00%		5.00%		6.00%		3.00%	4.00%	4.00%	4.30%	5.00%	6.00%	4.00%	5.04%	6.00%							3.83%										5.00%	4.00%	5.00%	4.00%	3.00%	4.00%	5.00%	4.00%	5.00%	4.00%	4.00%	5.00%							4.00%
Medical trend rates	5.00%	5.00%	5.00%	5.00%	[1]	5.00%	[1]	5.00%	[1]																5.00%	[1]	5.00%	[1]	5.00%	[1]		5.00%	5.00%	5.00%	5.00%	[2]	5.00%	[2]	5.00%	[2]													5.00%	[2]	5.00%	[2]	5.00%	[2]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets										7.00%	[3]	7.25%	[3]	8.25%	[3]																6.75%										6.75%	7.00%	7.25%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase																						4.00%	4.00%	4.00%																										4.00%	4.00%	4.00%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	8.00%	8.50%	9.00%	12.00%	[1]	12.50%	[1]	13.00%	[1]																8.00%	[1]	8.50%	[1]	9.00%	[1]		8.00%	8.00%	9.00%	12.00%	[2]	12.00%	[2]	13.00%	[2]													8.00%	[2]	8.00%	[2]	9.00%	[2]
Defined Benefit Plan, Year that Rate Reaches Ultimate Trend Rate	2019	2019	2019	2027	[1]	2027	[1]	2027	[1]																2019	[1]	2019	[1]	2019	[1]		2019	2019	2019	2027	[2]	2027	[2]	2027	[2]													2019	[2]	2019	[2]	2019	[2]

[1] The health care cost trend assumptions relate only to the postretirement benefit plans. Increasing or decreasing the assumed health care cost trend rates by one percentage point each future year would not have a material impact on total service and interest cost or the year end benefit obligation

[2] The health care cost trend assumptions relate only to the postretirement benefit plans. Increasing or decreasing the assumed health care cost trend rates by one percentage point each future year would not have a material impact on total service and interest cost or the year end benefit obligation.

[3] The Citizens Pension and Postretirement Plans were remeasured at the Acquisition Date based on discount rate of 3.83% and an expected long-term rate of return of 6.75%.