Loss and Loss Adjustment Expense Reserves (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Loss and Loss Adjustment Expense Reserves
Reserves for losses and LAE at beginning of year	$ 610,566	$ 584,719
Less receivable from reinsurers related to unpaid losses and LAE	(122,372)	(108,398)
Net reserves for losses and LAE at beginning of year	488,194	476,321
Incurred losses and LAE, related to:
Current year	343,393	408,927
Prior years	(34,619)	(25,541)
Total incurred losses and LAE	308,774	383,386
Paid losses and LAE related to:
Current year	180,649	226,660
Prior years	137,613	149,472
Total paid losses and LAE	318,262	376,132
Net reserves for losses and LAE at end of period	478,706	483,575
Plus receivable from reinsurers related to unpaid losses and LAE	107,783	117,884	$ 122,372
Reserves for losses and LAE at end of period	586,489	601,459
Prior years	$ 34,619	$ 25,541