Securities Amortized costs and fair values of securities available for sale (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 324,040	$ 328,027
Gross Unrealized Gains	8,013	5,815
Gross Unrealized Losses	(2,386)	(5,419)
Fair Value	329,667	328,423
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,512	21,367
Gross Unrealized Gains	222	304
Gross Unrealized Losses	(181)	(332)
Fair Value	27,553	21,339
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	60,126	68,904
Gross Unrealized Gains	1,960	1,083
Gross Unrealized Losses	(892)	(2,749)
Fair Value	61,194	67,238
Mortgage-backed securities, Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	172,315	166,095
Gross Unrealized Gains	4,933	3,539
Gross Unrealized Losses	(866)	(1,624)
Fair Value	176,382	168,010
Mortgage-backed securities, Non-agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,177	22,029
Gross Unrealized Gains	197	116
Gross Unrealized Losses	(74)	(211)
Fair Value	21,300	21,934
Other asset backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,248	33,883
Gross Unrealized Gains	512	710
Gross Unrealized Losses	(42)	(175)
Fair Value	25,718	34,418
Corporate preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68	69
Gross Unrealized Gains	18	5
Gross Unrealized Losses	0	0
Fair Value	86	74
Corporate securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,594	15,680
Gross Unrealized Gains	171	58
Gross Unrealized Losses	(331)	(328)
Fair Value	$ 17,434	$ 15,410