Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) Segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Information [Abstract]
Number of reportable segments | Segment									1
Revenues [Abstract]
Net premiums earned	$ 111,357	$ 110,288	$ 115,631	$ 110,012	$ 118,671	$ 96,807	$ 111,940	$ 105,462	$ 447,288	$ 432,880	$ 328,145
Net investment income	6,815	6,703	6,500	6,231	6,038	5,578	5,796	4,636	26,249	22,048	18,095
Net realized and unrealized gains (losses) on investments	$ 3,848	$ 125	$ 2,889	$ 6,027	$ (20,096)	$ 2,373	$ (3,435)	$ (4,533)	12,889	(25,691)	19,686
Commissions and other income									9,171	9,932	5,308
Total revenues									495,597	439,169	371,234
Property and Casualty Insurance [Member]
Revenues [Abstract]
Net premiums earned									447,288	432,880	328,145
Net investment income									26,249	22,048	18,095
Net realized and unrealized gains (losses) on investments									12,889	(25,691)	19,686
Commissions and other income									9,171	9,932	5,308
Total revenues									$ 495,597	$ 439,169	$ 371,234