Reserves for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Net reserves for unpaid losses and loss adjustment expenses, beginning of year	$ 313,763	$ 267,493
Incurred losses and loss adjustment expenses:
Current year	40,128	30,183
Prior years	(6,396)	(1,284)
Total net losses and loss adjustment expenses incurred	33,732	28,899
Payments:
Current year	2,042	340
Prior years	17,955	17,516
Total payments	19,997	17,856
Net reserves for unpaid losses and loss adjustment expenses, end of period	327,498	278,536
Reinsurance recoverable on unpaid losses	57,627	49,673
Gross reserves for unpaid losses and loss adjustment expenses, end of period	$ 385,125	$ 328,209