Schedule VI - Supplemental Information Concerning Insurance Operations - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Earned premiums		$ 333,481	$ 261
Net investment income		10,254	9,063
Claim and claim adjustment expenses incurred related to current year	$ 231,133	245,545	201,704
Claim and claim adjustment expenses incurred related to prior year	(2,717)	2,012	(3,894)
Property and Casualty Insurance [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Deferred acquisition costs	39,436	40,893	41,892
Loss and loss adjustment expense reserves	296,230	230,515	158,110
Unearned premiums	281,992	294,423	294,022
Earned premiums	355,257
Net investment income	12,460
Claim and claim adjustment expenses incurred related to current year	231,133	245,545	201,704
Claim and claim adjustment expenses incurred related to prior year	(2,717)	2,012	(3,894)
Supplemental Information for Property, Casualty Insurance Underwriters, Amortization of Deferred Policy Acquisition Costs	97,873	87,310	57,452
Paid claims and claims adjustment expense	230,752	233,085	170,322
Supplemental Information for Property, Casualty Insurance Underwriters, Premiums Written	$ 365,032	$ 342,893	$ 319,499