SCHEDULE VI--SUPPLEMENTAL INFORMATION CONCERNING PROPERTY/CASUALTY INSURANCE OPERATIONS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Information, Property-Casualty Insurance [Abstract]
Deferred policy acquisition costs	$ 6,568	$ 5,608	$ 1,172
Reserves for unpaid claims and claim adjustment expenses	865,339	680,274	576,330
Discount if any deducted in Column C	0	0	0
Unearned premiums	71,625	53,085	21,694
Earned premiums	432,880	328,145	276,011
Net investment income	22,048	18,095	14,483
Claims and claim adjustment expenses incurred related to current year	329,078	228,303	172,645
Claims and claim adjustment expenses incurred related to prior years	16,786	19,215	13,836
Amortization of deferred policy acquisition costs	78,105	70,574	51,597
Paid claims and claim adjustment expenses	228,591	200,154	163,467
Net premiums written	$ 444,398	$ 353,389	$ 271,752
Loss reserve discounted present value cash flow pretax interest rate utilized			3.50%