Accounting for Certain Loans Acquired in a Purchase - Accretable Yield or Income Expected to be Collected (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	$ 17,154		$ 19,299
Accretion	(3,484)		(7,426)
Reclassification from nonaccretable	2,930		5,100
Disposals	(1,708)		(2,081)
Ending balance	14,892		14,892
Merger with CFS Bancorp, Inc. (Citizens)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	12,085		13,435
Accretion	(2,791)		(5,677)
Reclassification from nonaccretable	2,601		4,382
Disposals	(1,345)		(1,590)
Ending balance	10,550		10,550
SCB Bank
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	5,069	3,959	5,864	5,142
Additions
Accretion	(693)	(413)	(1,749)	(1,596)
Reclassification from nonaccretable	329		718
Disposals	(363)		(491)
Ending balance	$ 4,342	$ 3,546	$ 4,342	$ 3,546