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
	Mar. 31, 2014	Mar. 31, 2013
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	$ 19,299
Accretion	(1,769)
Reclassification from nonaccretable	491
Disposals	(195)
Ending balance	17,826
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	13,435
Accretion	(1,155)
Reclassification from nonaccretable	238
Disposals	(107)
Ending balance	12,411
SCB Bank
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	5,864
Additions		5,142
Accretion	(614)	(771)
Reclassification from nonaccretable	253
Disposals	(88)
Ending balance	$ 5,415	$ 4,371