Securities Amortized costs and fair values of securities available for sale (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 322,693	$ 328,027
Gross Unrealized Gains	6,407	5,815
Gross Unrealized Losses	(3,580)	(5,419)
Fair Value	325,520	328,423
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,378	21,367
Gross Unrealized Gains	179	304
Gross Unrealized Losses	(282)	(332)
Fair Value	22,275	21,339
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	65,389	68,904
Gross Unrealized Gains	1,507	1,083
Gross Unrealized Losses	(1,580)	(2,749)
Fair Value	65,316	67,238
Mortgage-backed securities, Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	169,425	166,095
Gross Unrealized Gains	3,970	3,539
Gross Unrealized Losses	(1,251)	(1,624)
Fair Value	172,144	168,010
Mortgage-backed securities, Non-agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,012	22,029
Gross Unrealized Gains	151	116
Gross Unrealized Losses	(126)	(211)
Fair Value	23,037	21,934
Other asset backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,007	33,883
Gross Unrealized Gains	540	710
Gross Unrealized Losses	(82)	(175)
Fair Value	27,465	34,418
Corporate preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68	69
Gross Unrealized Gains	10	5
Gross Unrealized Losses	0	0
Fair Value	78	74
Corporate securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,414	15,680
Gross Unrealized Gains	50	58
Gross Unrealized Losses	(259)	(328)
Fair Value	$ 15,205	$ 15,410