Securities Available-for-Sale (Details) - Unrealized gains on investment securities - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Securities available-for-sale
Securities, Amortized Cost	$ 421,147	$ 436,868
Securities, Gross Unrealized Gains	974	2,886
Securities, Gross Unrealized Losses	(12,082)	(4,470)
Securities, Fair Value	410,039	435,284
Federal agency obligations [Member]
Securities available-for-sale
Securities, Amortized Cost	48,963	56,297
Securities, Gross Unrealized Gains	14	141
Securities, Gross Unrealized Losses	(1,443)	(416)
Securities, Fair Value	47,534	56,022
Residential mortgage pass-through securities [Member]
Securities available-for-sale
Securities, Amortized Cost	196,650	183,509
Securities, Gross Unrealized Gains	75	330
Securities, Gross Unrealized Losses	(6,174)	(1,948)
Securities, Fair Value	190,551	181,891
Commercial mortgage pass-through securities [Member]
Securities available-for-sale
Securities, Amortized Cost	3,953	4,054
Securities, Gross Unrealized Gains		3
Securities, Gross Unrealized Losses	(110)	(3)
Securities, Fair Value	3,843	4,054
Obligations of U.S. states and political subdivisions [Member]
Securities available-for-sale
Securities, Amortized Cost	133,564	130,723
Securities, Gross Unrealized Gains	727	1,739
Securities, Gross Unrealized Losses	(3,903)	(1,334)
Securities, Fair Value	130,388	131,128
Corporate bonds and notes [Member]
Securities available-for-sale
Securities, Amortized Cost	26,305	29,801
Securities, Gross Unrealized Gains	96	163
Securities, Gross Unrealized Losses	(439)	(271)
Securities, Fair Value	25,962	29,693
Asset-backed securities [Member]
Securities available-for-sale
Securities, Amortized Cost	10,317	12,021
Securities, Gross Unrealized Gains	59	66
Securities, Gross Unrealized Losses	(13)	(37)
Securities, Fair Value	10,363	12,050
Certificates of deposit [Member]
Securities available-for-sale
Securities, Amortized Cost	420	621
Securities, Gross Unrealized Gains	3	4
Securities, Gross Unrealized Losses
Securities, Fair Value	423	625
Other securities [Member]
Securities available-for-sale
Securities, Amortized Cost	975	3,422
Securities, Gross Unrealized Gains
Securities, Gross Unrealized Losses
Securities, Fair Value	$ 975	3,422
Trust preferred securities [Member]
Securities available-for-sale
Securities, Amortized Cost		4,577
Securities, Gross Unrealized Gains		205
Securities, Gross Unrealized Losses		(111)
Securities, Fair Value		4,671
Equity securities [Member]
Securities available-for-sale
Securities, Amortized Cost		11,843
Securities, Gross Unrealized Gains		235
Securities, Gross Unrealized Losses		(350)
Securities, Fair Value		$ 11,728