Securities - Securities with Unrealized Losses at Year End - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Held-to-maturity, Fair Value
Less Than 12 Months	$ 9,348	$ 17,072
12 Months or More	22,348	28,821
Total	31,696	45,893
Held-to-maturity, Unrealized Losses
Less Than 12 Months	(38)	(167)
12 Months or More	(467)	(864)
Total	(505)	(1,031)
Municipals - tax exempt
Held-to-maturity, Fair Value
Less Than 12 Months	2,051	9,920
12 Months or More	18,643	24,412
Total	20,694	34,332
Held-to-maturity, Unrealized Losses
Less Than 12 Months	(24)	(78)
12 Months or More	(434)	(785)
Total	(458)	(863)
Agency mortgage-backed securities
Held-to-maturity, Fair Value
Less Than 12 Months	7,297	7,152
12 Months or More	3,705	4,409
Total	11,002	11,561
Held-to-maturity, Unrealized Losses
Less Than 12 Months	(14)	(89)
12 Months or More	(33)	(79)
Total	$ (47)	$ (168)