Accumulated Other Comprehensive Income - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains	$ 208	$ 315
Other-than-temporary impairment loss	(117)	(75)
(Loss) income before income tax expense (benefit)	(223)	2,476
Income tax expense (benefit)	170	(713)
Net (loss) income	(393)	3,189
Unrealized Gains (Losses) on Available-for-Sale Investments | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains	(61)	6
Other-than-temporary impairment loss	0	0
(Loss) income before income tax expense (benefit)	(61)	6
Income tax expense (benefit)	0	0
Net (loss) income	$ (61)	$ 6