Securities - Securities in Continuous Unrealized Loss Position (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Available-for-sale, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months	$ 93,369	$ 169,166
Gross Unrealized Losses, Less than 12 Months	(177)	(584)
Fair Value, Less than 12 Months	93,192	168,582
Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months	9,688	13,165
Gross Unrealized Losses, Less than 12 Months	(32)	(121)
Fair Value, Less than 12 Months	9,656	13,044
Amortized Cost, More than 12 Months	12,587	15,442
Gross Unrealized Losses, More than 12 Months	(267)	(387)
Fair Value, More than 12 Months	$ 12,320	$ 15,055
Investment Securities Continuous Unrealized Loss Position Qualitative Disclosure Abstract
Securities in Unrealized Loss Position, Continuour Unrealized Loss as percent of Amortized Cost	10	10
US Treasury and Government [Member]
Available-for-sale, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months	$ 50,007	$ 85,028
Gross Unrealized Losses, Less than 12 Months	(1)	(85)
Fair Value, Less than 12 Months	50,006	84,943
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months	4,689	48,830
Gross Unrealized Losses, Less than 12 Months	(15)	(184)
Fair Value, Less than 12 Months	4,674	48,646
Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months		3,220
Gross Unrealized Losses, Less than 12 Months		(48)
Fair Value, Less than 12 Months		3,172
Amortized Cost, More than 12 Months	3,744	2,571
Gross Unrealized Losses, More than 12 Months	(64)	(95)
Fair Value, More than 12 Months	3,680	2,476
Collateralized Mortgage Backed Securities [Member]
Available-for-sale, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months	38,673	33,299
Gross Unrealized Losses, Less than 12 Months	(161)	(314)
Fair Value, Less than 12 Months	38,512	32,985
Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months	9,688	9,945
Gross Unrealized Losses, Less than 12 Months	(32)	(73)
Fair Value, Less than 12 Months	9,656	9,872
Amortized Cost, More than 12 Months	8,843	12,871
Gross Unrealized Losses, More than 12 Months	(203)	(292)
Fair Value, More than 12 Months	$ 8,640	12,579
Corporate debt securities
Available-for-sale, Continuous Unrealized Loss Position [Abstract]
Amortized Cost, Less than 12 Months		2,009
Gross Unrealized Losses, Less than 12 Months		(1)
Fair Value, Less than 12 Months		$ 2,008