Securities - Investments in continuous unrealized loss position (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Held to Maturity, Fair Value, Less than Twelve Months	$ 1,375	$ 1,397
Held to Maturity, Gross Unrealized Losses, Less than Twelve Months	(125)	(103)
Held to Maturity, Fair Value, Twelve Months or Greater	0	0
Held to Maturity, Gross Unrealized Losses, Twelve Months or Greater	0	0
Held to Maturity, Fair Value	1,375	1,397
Held to Maturity, Gross Unrealized Losses, Total	(125)	(103)
Fair Value, Less than Twelve Months	93,692	77,450
Gross Unrealized Losses, Less than Twelve Months	(1,158)	(1,009)
Fair Value, Twelve Months or Greater	29,683	26,915
Gross Unrealized Losses, Twelve Months or Greater	(1,006)	(1,029)
Fair Value, Total	123,375	104,365
Gross Unrealized Losses, Total	(2,164)	(2,038)
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	12,515	15,331
Gross Unrealized Losses, Less than Twelve Months	(24)	(65)
Fair Value, Twelve Months or Greater	2,481	5,833
Gross Unrealized Losses, Twelve Months or Greater	(34)	(138)
Fair Value, Total	14,996	21,164
Gross Unrealized Losses, Total	(58)	(203)
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Held to Maturity, Fair Value, Less than Twelve Months	1,375	1,397
Held to Maturity, Gross Unrealized Losses, Less than Twelve Months	(125)	(103)
Held to Maturity, Fair Value, Twelve Months or Greater	0	0
Held to Maturity, Gross Unrealized Losses, Twelve Months or Greater	0	0
Held to Maturity, Fair Value	1,375	1,397
Held to Maturity, Gross Unrealized Losses, Total	(125)	(103)
Fair Value, Less than Twelve Months	18,340	2,780
Gross Unrealized Losses, Less than Twelve Months	(306)	(14)
Fair Value, Twelve Months or Greater	978	3,456
Gross Unrealized Losses, Twelve Months or Greater	(164)	(195)
Fair Value, Total	19,318	6,236
Gross Unrealized Losses, Total	(470)	(209)
Mortgage-backed securities, Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	18,710	28,065
Gross Unrealized Losses, Less than Twelve Months	(148)	(327)
Fair Value, Twelve Months or Greater	9,372	11,027
Gross Unrealized Losses, Twelve Months or Greater	(286)	(415)
Fair Value, Total	28,082	39,092
Gross Unrealized Losses, Total	(434)	(742)
Mortgage-backed securities, Non-agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	9,370	15,488
Gross Unrealized Losses, Less than Twelve Months	(46)	(167)
Fair Value, Twelve Months or Greater	1,861	4,730
Gross Unrealized Losses, Twelve Months or Greater	(14)	(60)
Fair Value, Total	11,231	20,218
Gross Unrealized Losses, Total	(60)	(227)
Other asset backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	21,564	6,594
Gross Unrealized Losses, Less than Twelve Months	(220)	(45)
Fair Value, Twelve Months or Greater	12,244	1,077
Gross Unrealized Losses, Twelve Months or Greater	(255)	(13)
Fair Value, Total	33,808	7,671
Gross Unrealized Losses, Total	(475)	(58)
Corporate securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	13,193	9,192
Gross Unrealized Losses, Less than Twelve Months	(414)	(391)
Fair Value, Twelve Months or Greater	2,747	792
Gross Unrealized Losses, Twelve Months or Greater	(253)	(208)
Fair Value, Total	15,940	9,984
Gross Unrealized Losses, Total	$ (667)	$ (599)