Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Liability for Unpaid Claims and Claims Adjustment Expense
Unpaid losses and loss adjustment expenses	$ 577,349	$ 432,431	$ 661,203	$ 482,232
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	379,402	266,265	477,870	305,673
Liability for Unpaid Claims and Claims Adjustment Expense, Net	197,947	166,166	$ 183,333	$ 176,559
Current Year Claims and Claims Adjustment Expense	199,832	167,392
Prior Year Claims and Claims Adjustment Expense	20,967	(1,551)
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	220,799	165,841
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	108,042	83,297
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	98,143	92,937
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	206,185	176,234
Liability for Unpaid Claims and Claims Adjustment Expense, Reported Claims, Amount	257,873	230,926
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 319,476	$ 201,505