Other Comprehensive Income - Summary of Reclassifications out of Accumulated Other Comprehensive Income ("AOCI") (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains and losses on available for sale securities	$ 6	$ 2	$ (81)	$ 2
Tax benefit or (expense)	(1,540)	(1,901)	(3,280)	(3,517)
Net income	4,272	6,111	10,470	11,916
Reclassifications out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Unrealized gains and losses on available for sale securities	6	2	(81)	2
Tax benefit or (expense)	(2)		19
Net income	$ 4	$ 2	$ (62)	$ 2