Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	9 Months Ended
	May. 13, 2015	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Shareholders Equity Narrative [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			800,000	900,000
Payments for Repurchase of Warrants	$ 12,200		$ 12,150	$ 0
Adjustments to Additional Paid in Capital, Other		$ (9,200)
5.875% Non-Cumulative Perpetual Preferred stock, Series A, authorized 115,000 shares		7,000,000	7,000,000
Non-cumulative Perpetual Preferred Stock, Series A, Shares Authorized		115,000	115,000	115,000	115,000
5.875% Non-Cumulative Perpetual Preferred stock, Series A, 100,000 outstanding		100,000	100,000	100,000	100,000
Citizens Republic Bancorp
Shareholders Equity Narrative [Line Items]
Interest rate of Non-Cumulative Perpetual Preferred Stock, Series A		5.875%	5.875%
Citizens Republic Bancorp | Citizens Republic Bancorp
Shareholders Equity Narrative [Line Items]
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 17.50	$ 17.50
FirstMerit | Citizens Republic Bancorp
Shareholders Equity Narrative [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		2,571,998.380	2,571,998.380