Securities - Investments in continuous unrealized loss position (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Held to Maturity, Fair Value, Less than Twelve Months	$ 1,422	$ 3,389
Held to Maturity, Gross Unrealized Losses, Less than Twelve Months	(35)	(68)
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	1,422	3,389
Held to Maturity, Gross Unrealized Losses, Total	(35)	(68)
Fair Value, Less than Twelve Months	67,781	134,167
Gross Unrealized Losses, Less than Twelve Months	(971)	(1,721)
Fair Value, Twelve Months or Greater	46,356	32,790
Gross Unrealized Losses, Twelve Months or Greater	(1,852)	(1,239)
Fair Value, Total	114,137	166,957
Gross Unrealized Losses, Total	(2,823)	(2,960)
U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	11,671	46,000
Gross Unrealized Losses, Less than Twelve Months	(68)	(304)
Fair Value, Twelve Months or Greater	2,840	4,223
Gross Unrealized Losses, Twelve Months or Greater	(25)	(76)
Fair Value, Total	14,511	50,223
Gross Unrealized Losses, Total	(93)	(380)
Obligations of states and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Held to Maturity, Fair Value, Less than Twelve Months	1,422	1,419
Held to Maturity, Gross Unrealized Losses, Less than Twelve Months	(35)	(38)
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	1,422	1,419
Held to Maturity, Gross Unrealized Losses, Total	(35)	(38)
Fair Value, Less than Twelve Months	4,641	16,559
Gross Unrealized Losses, Less than Twelve Months	(50)	(324)
Fair Value, Twelve Months or Greater	6,589	1,082
Gross Unrealized Losses, Twelve Months or Greater	(305)	(110)
Fair Value, Total	11,230	17,641
Gross Unrealized Losses, Total	(355)	(434)
Mortgage-backed securities, Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	17,296	27,627
Gross Unrealized Losses, Less than Twelve Months	(186)	(402)
Fair Value, Twelve Months or Greater	10,814	9,911
Gross Unrealized Losses, Twelve Months or Greater	(435)	(343)
Fair Value, Total	28,110	37,538
Gross Unrealized Losses, Total	(621)	(745)
Mortgage-backed securities, Non-agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	2,069	7,842
Gross Unrealized Losses, Less than Twelve Months	(26)	(37)
Fair Value, Twelve Months or Greater	999	671
Gross Unrealized Losses, Twelve Months or Greater	(33)	(1)
Fair Value, Total	3,068	8,513
Gross Unrealized Losses, Total	(59)	(38)
Other asset backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value, Less than Twelve Months	30,654	25,399
Gross Unrealized Losses, Less than Twelve Months	(541)	(276)
Fair Value, Twelve Months or Greater	14,004	12,037
Gross Unrealized Losses, Twelve Months or Greater	(352)	(327)
Fair Value, Total	44,658	37,436
Gross Unrealized Losses, Total	(893)	(603)
Corporate securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Held to Maturity, Fair Value, Less than Twelve Months		1,970
Held to Maturity, Gross Unrealized Losses, Less than Twelve Months		(30)
Held to Maturity, Fair Value, Twelve Months or Greater		0
Held to Maturity, Gross Unrealized Losses, Twelve Months or Greater		0
Held to Maturity, Fair Value		1,970
Held to Maturity, Gross Unrealized Losses, Total		(30)
Fair Value, Less than Twelve Months	1,450	10,740
Gross Unrealized Losses, Less than Twelve Months	(100)	(378)
Fair Value, Twelve Months or Greater	11,110	4,866
Gross Unrealized Losses, Twelve Months or Greater	(702)	(382)
Fair Value, Total	12,560	15,606
Gross Unrealized Losses, Total	$ (802)	$ (760)