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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	$ 17,826		$ 19,299
Accretion	(2,173)		(3,942)
Reclassification from nonaccretable	1,679		2,170
Disposals	(178)		(373)
Ending balance	17,154		17,154
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	12,411		13,435
Accretion	(1,731)		(2,886)
Reclassification from nonaccretable	1,543		1,781
Disposals	(138)		(245)
Ending balance	12,085		12,085
SCB Bank
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	5,415	4,371	5,864	5,142
Additions
Accretion	(442)	(412)	(1,056)	(1,183)
Reclassification from nonaccretable	136		389
Disposals	(40)		(128)
Ending balance	$ 5,069	$ 3,959	$ 5,069	$ 3,959