Securities Available-for-Sale (Details) - Unrealized gains on investment securities - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investment securities available-for-sale
Investment Securities, Amortized Cost	$ 430,810	$ 436,868
Investment Securities, Gross Unrealized Gains	1,644	2,886
Investment Securities, Gross Unrealized Losses	(8,132)	(4,470)
Investment Securities, Fair Value	424,322	435,284
Investment securities available-for-sale, Fair Value	11,607
Federal Agency Obligations [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	53,318	56,297
Investment Securities, Gross Unrealized Gains	29	141
Investment Securities, Gross Unrealized Losses	(876)	(416)
Investment Securities, Fair Value	52,471	56,022
Residential mortgage pass-through securities [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	192,537	183,509
Investment Securities, Gross Unrealized Gains	180	330
Investment Securities, Gross Unrealized Losses	(3,960)	(1,948)
Investment Securities, Fair Value	188,757	181,891
Commercial mortgage pass-through securities [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	4,020	4,054
Investment Securities, Gross Unrealized Gains		3
Investment Securities, Gross Unrealized Losses	(61)	(3)
Investment Securities, Fair Value	3,959	4,054
Obligations of U.S. states and political subdivisions [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	128,941	130,723
Investment Securities, Gross Unrealized Gains	1,167	1,739
Investment Securities, Gross Unrealized Losses	(2,738)	(1,334)
Investment Securities, Fair Value	127,370	131,128
Trust Preferred Securities [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	4,577	4,577
Investment Securities, Gross Unrealized Gains	120	205
Investment Securities, Gross Unrealized Losses	(83)	(111)
Investment Securities, Fair Value	4,614	4,671
Corporate Bonds And Notes [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	29,302	29,801
Investment Securities, Gross Unrealized Gains	93	163
Investment Securities, Gross Unrealized Losses	(392)	(271)
Investment Securities, Fair Value	29,003	29,693
Asset-backed Securities [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	11,463	12,021
Investment Securities, Gross Unrealized Gains	53	66
Investment Securities, Gross Unrealized Losses	(22)	(37)
Investment Securities, Fair Value	11,494	12,050
Certificates of Deposit [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	621	621
Investment Securities, Gross Unrealized Gains	2	4
Investment Securities, Gross Unrealized Losses
Investment Securities, Fair Value	623	625
Equity Securities [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost		11,843
Investment Securities, Gross Unrealized Gains		235
Investment Securities, Gross Unrealized Losses		(350)
Investment Securities, Fair Value		11,728
Other Securities [Member]
Investment securities available-for-sale
Investment Securities, Amortized Cost	6,031	3,422
Investment Securities, Gross Unrealized Gains
Investment Securities, Gross Unrealized Losses
Investment Securities, Fair Value	$ 6,031	$ 3,422