Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized (losses) gains arising during the period, before income taxes	$ (2,472)	$ 2,552	$ (9,665)	$ 7,539
Income taxes	519	(893)	2,030	(2,638)
Unrealized (losses) gains arising during the period, net of income tax	(1,953)	1,659	(7,635)	4,901
Less reclassification adjustment [Abstract]
Net realized investment gains on fixed-maturity securities, before income taxes	0	31	240	23
Income taxes	0	(11)	(50)	(8)
Reclassification adjustment included in net income	0	20	190	15
Other comprehensive (loss) income	(1,953)	1,639	(7,825)	4,886
Fixed maturities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized (losses) gains arising during the period, before income taxes	(2,472)	1,416	(9,665)	4,905
Equity securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized (losses) gains arising during the period, before income taxes	$ 0	$ 1,136	$ 0	$ 2,634