Investment Securities - Gross Unrealized Losses and Fair Value Aggregated by Investment Category and Length of Time in Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investment Securities
Less than 12 months Fair Value	$ 18,186	$ 20,188
Less than 12 months Unrealized Loss	(340)	(198)
12 months or more Fair Value	50,327	40,641
12 months or more Unrealized Loss	(1,741)	(1,084)
Total Fair Value	68,513	60,829
Total Unrealized Loss	(2,081)	(1,282)
Collateralized mortgage obligations
Investment Securities
Less than 12 months Fair Value	1,625	6,531
Less than 12 months Unrealized Loss	(22)	(63)
12 months or more Fair Value	17,546	15,678
12 months or more Unrealized Loss	(640)	(507)
Total Fair Value	19,171	22,209
Total Unrealized Loss	(662)	(570)
Agency mortgage-backed securities.
Investment Securities
Less than 12 months Fair Value	3,399	6,802
Less than 12 months Unrealized Loss	(74)	(80)
12 months or more Fair Value	21,417	18,218
12 months or more Unrealized Loss	(840)	(420)
Total Fair Value	24,816	25,020
Total Unrealized Loss	(914)	(500)
Municipal securities
Investment Securities
Less than 12 months Fair Value	13,162	2,396
Less than 12 months Unrealized Loss	(244)	(11)
12 months or more Fair Value	8,415	6,230
12 months or more Unrealized Loss	(210)	(148)
Total Fair Value	21,577	8,626
Total Unrealized Loss	(454)	(159)
U.S. Government agency securities
Investment Securities
Less than 12 months Fair Value		2,965
Less than 12 months Unrealized Loss		(37)
12 months or more Fair Value	1,959	515
12 months or more Unrealized Loss	(40)	(9)
Total Fair Value	1,959	3,480
Total Unrealized Loss	(40)	(46)
U.S. Treasury securities
Investment Securities
Less than 12 months Fair Value		1,494
Less than 12 months Unrealized Loss		(7)
12 months or more Fair Value	990
12 months or more Unrealized Loss	(11)
Total Fair Value	990	1,494
Total Unrealized Loss	$ (11)	$ (7)