Schedule VI - Supplemental Information Concerning Insurance Operations - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Claim and claim adjustment expenses incurred related to current year	$ 262,118	$ 231,133	$ 245,545
Claim and claim adjustment expenses incurred related to prior year	10,971	(2,717)	2,012
Property and Casualty Insurance [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred acquisition costs	56,136	39,436	40,893
Loss and loss adjustment expense reserves	324,362	296,230	230,515
Unearned premiums	360,870	281,992	294,423
Earned premiums	363,652	355,257	333,481
Net investment income	15,901	12,460	10,254
Claim and claim adjustment expenses incurred related to current year	262,109	231,133	245,545
Claim and claim adjustment expenses incurred related to prior year	10,971	(2,717)	2,012
Supplemental Information for Property, Casualty Insurance Underwriters, Amortization of Deferred Policy Acquisition Costs	96,885	97,873	87,310
Paid claims and claims adjustment expense	254,806	230,752	233,085
Supplemental Information for Property, Casualty Insurance Underwriters, Premiums Written	$ 377,879	$ 365,032	$ 342,893