Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Goodwill	$ 739,819	$ 460,044	$ 460,044
Commercial
Goodwill [Line Items]
Goodwill	527,406	384,721	384,721
Goodwill, Acquired During Period	142,685
Retail
Goodwill [Line Items]
Goodwill	192,040	66,141	66,141
Goodwill, Acquired During Period	125,899
Wealth
Goodwill [Line Items]
Goodwill	20,373	9,182	9,182
Goodwill, Acquired During Period	11,191
Citizens Republic Bancorp
Goodwill [Line Items]
Goodwill, Acquired During Period	$ 279,775