Securities - Securities in Unrealized Loss Position (Details) $ in Thousands	Mar. 31, 2017 USD ($) security	Dec. 31, 2016 USD ($) security
Available for sale at fair value:
Available for sale, Total number in a loss position | security	31	24
Available for sale, Less than 12 months Estimated fair value	$ 27,588	$ 14,430
Available for sale, Less than 12 months Unrealized loss	(446)	(298)
Available for sale, 12 months and greater, Estimated fair value	4,538	8,359
Available for sale, 12 months and greater, Unrealized loss	(306)	(333)
Available for sale, Total Estimated fair value	32,126	22,789
Available for sale, Total Unrealized loss	$ (752)	$ (631)
Held to maturity at cost:
Held to maturity, Total number in a loss position | security	9	7
Held to maturity, Less than 12 months Estimated fair value	$ 9,418	$ 8,038
Held to maturity, Less than 12 months Unrealized loss	(331)	(292)
Held to maturity, 12 months and greater, Estimated fair value	426	441
Held to maturity, 12 months and greater, Unrealized loss	(14)	(10)
Held to maturity, Total Estimated fair value	9,844	8,479
Held to maturity, Total Unrealized loss	$ (345)	$ (302)
U.S. Government sponsored entities
Available for sale at fair value:
Available for sale, Total number in a loss position | security	1	1
Available for sale, Less than 12 months Estimated fair value	$ 1,966	$ 1,962
Available for sale, Less than 12 months Unrealized loss	(26)	(30)
Available for sale, 12 months and greater, Estimated fair value	0	0
Available for sale, 12 months and greater, Unrealized loss	0	0
Available for sale, Total Estimated fair value	1,966	1,962
Available for sale, Total Unrealized loss	$ (26)	$ (30)
Held to maturity at cost:
Held to maturity, Total number in a loss position | security	2	2
Held to maturity, Less than 12 months Estimated fair value	$ 3,413	$ 3,402
Held to maturity, Less than 12 months Unrealized loss	(116)	(128)
Held to maturity, 12 months and greater, Estimated fair value	0	0
Held to maturity, 12 months and greater, Unrealized loss	0	0
Held to maturity, Total Estimated fair value	3,413	3,402
Held to maturity, Total Unrealized loss	$ (116)	$ (128)
State and political subdivisions
Available for sale at fair value:
Available for sale, Total number in a loss position | security	4	4
Available for sale, Less than 12 months Estimated fair value	$ 3,797	$ 3,833
Available for sale, Less than 12 months Unrealized loss	(77)	(62)
Available for sale, 12 months and greater, Estimated fair value	0	0
Available for sale, 12 months and greater, Unrealized loss	0	0
Available for sale, Total Estimated fair value	3,797	3,833
Available for sale, Total Unrealized loss	$ (77)	$ (62)
Held to maturity at cost:
Held to maturity, Total number in a loss position | security		1
Held to maturity, Less than 12 months Estimated fair value		$ 212
Held to maturity, Less than 12 months Unrealized loss		(1)
Held to maturity, 12 months and greater, Estimated fair value		0
Held to maturity, 12 months and greater, Unrealized loss		0
Held to maturity, Total Estimated fair value		212
Held to maturity, Total Unrealized loss		$ (1)
Residential mortgage-backed securities
Available for sale at fair value:
Available for sale, Total number in a loss position | security	20	13
Available for sale, Less than 12 months Estimated fair value	$ 18,727	$ 7,813
Available for sale, Less than 12 months Unrealized loss	(261)	(139)
Available for sale, 12 months and greater, Estimated fair value	2,675	2,983
Available for sale, 12 months and greater, Unrealized loss	(120)	(116)
Available for sale, Total Estimated fair value	21,402	10,796
Available for sale, Total Unrealized loss	$ (381)	$ (255)
Held to maturity at cost:
Held to maturity, Total number in a loss position | security	4	2
Held to maturity, Less than 12 months Estimated fair value	$ 897	$ 776
Held to maturity, Less than 12 months Unrealized loss	(22)	(15)
Held to maturity, 12 months and greater, Estimated fair value	426	441
Held to maturity, 12 months and greater, Unrealized loss	(14)	(10)
Held to maturity, Total Estimated fair value	1,323	1,217
Held to maturity, Total Unrealized loss	$ (36)	$ (25)
Commercial mortgage-backed securities
Held to maturity at cost:
Held to maturity, Total number in a loss position | security	2	2
Held to maturity, Less than 12 months Estimated fair value	$ 3,589	$ 3,648
Held to maturity, Less than 12 months Unrealized loss	(179)	(148)
Held to maturity, 12 months and greater, Estimated fair value	0	0
Held to maturity, 12 months and greater, Unrealized loss	0	0
Held to maturity, Total Estimated fair value	3,589	3,648
Held to maturity, Total Unrealized loss	$ (179)	$ (148)
Corporate and other securities
Available for sale at fair value:
Available for sale, Total number in a loss position | security	6	6
Available for sale, Less than 12 months Estimated fair value	$ 3,098	$ 822
Available for sale, Less than 12 months Unrealized loss	(82)	(67)
Available for sale, 12 months and greater, Estimated fair value	1,863	5,376
Available for sale, 12 months and greater, Unrealized loss	(186)	(217)
Available for sale, Total Estimated fair value	4,961	6,198
Available for sale, Total Unrealized loss	$ (268)	$ (284)
Held to maturity at cost:
Held to maturity, Total number in a loss position | security	1
Held to maturity, Less than 12 months Estimated fair value	$ 1,519
Held to maturity, Less than 12 months Unrealized loss	(14)
Held to maturity, 12 months and greater, Estimated fair value	0
Held to maturity, 12 months and greater, Unrealized loss	0
Held to maturity, Total Estimated fair value	1,519
Held to maturity, Total Unrealized loss	$ (14)