Accounting for Certain Loans Acquired in a Purchase - Accretable Yield or Income Expected to be Collected (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	$ 5,612	$ 5,390	$ 5,552
Additions		2,305	2,234
Accretion	(6,577)	(5,850)	(5,439)
Reclassification from nonaccretable	5,172	3,925	3,249
Disposals	(257)	(158)	(206)
Ending balance	3,950	5,612	5,390
Ameriana
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	2,160
Additions		2,160
Accretion	(311)
Reclassification from nonaccretable	12
Disposals	(232)
Ending balance	1,629	2,160
C Financial
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	114
Additions		145
Accretion	(123)	(31)
Reclassification from nonaccretable	82
Ending balance	73	114
Community
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	1,508	2,122
Accretion	(1,119)	(723)	(231)
Reclassification from nonaccretable	858	249	119
Disposals	(14)	(140)
Ending balance	1,233	1,508	2,122
CFS
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	1,188	2,400	4,164
Accretion	(4,268)	(4,050)	(4,146)
Reclassification from nonaccretable	3,827	2,854	2,553
Disposals	(11)	(16)	(171)
Ending balance	736	1,188	2,400
SCB
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Beginning balance	642	868	1,388
Accretion	(756)	(1,046)	(1,062)
Reclassification from nonaccretable	393	822	577
Disposals		(2)	(35)
Ending balance	$ 279	$ 642	$ 868