Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) Segment	Mar. 31, 2018 USD ($)
Segment Information [Abstract]
Number of reportable segments | Segment	1
Summary of Segment Revenue [Abstract]
Net premiums earned	$ 110,013	$ 105,462
Net investment income	6,232	4,636
Net realized and unrealized gains (losses) on investments	6,028	(4,533)
Commissions and other income	2,064	1,814
Total revenues	124,337	107,379
Property and Casualty Insurance [Member]
Summary of Segment Revenue [Abstract]
Net premiums earned	110,013	105,462
Net investment income	6,232	4,636
Net realized and unrealized gains (losses) on investments	6,028	(4,533)
Commissions and other income	2,064	1,814
Total revenues	$ 124,337	$ 107,379