Securities Amortized costs and fair values of securities available for sale (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 342,233	$ 328,027
Gross Unrealized Gains	8,068	5,815
Gross Unrealized Losses	(2,038)	(5,419)
Fair Value	348,263	328,423
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	41,317	21,367
Gross Unrealized Gains	283	304
Gross Unrealized Losses	(203)	(332)
Fair Value	41,397	21,339
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	55,541	68,904
Gross Unrealized Gains	2,408	1,083
Gross Unrealized Losses	(209)	(2,749)
Fair Value	57,740	67,238
Mortgage-backed securities, Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	169,257	166,095
Gross Unrealized Gains	4,698	3,539
Gross Unrealized Losses	(742)	(1,624)
Fair Value	173,213	168,010
Mortgage-backed securities, Non-agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,235	22,029
Gross Unrealized Gains	115	116
Gross Unrealized Losses	(227)	(211)
Fair Value	28,123	21,934
Other Asset Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	31,338	33,883
Gross Unrealized Gains	433	710
Gross Unrealized Losses	(58)	(175)
Fair Value	31,713	34,418
Corporate preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		69
Gross Unrealized Gains		5
Gross Unrealized Losses		0
Fair Value		74
Corporate securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,545	15,680
Gross Unrealized Gains	131	58
Gross Unrealized Losses	(599)	(328)
Fair Value	$ 16,077	$ 15,410