Reserves for Losses and Loss Adjustment Expenses (Activity in the Reserves for Unpaid Losses and Loss Adjustment Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reserves for Losses and Loss Adjustment Expenses [Abstract]
Balance at January 1	$ 789,768	$ 620,355
Less reinsurance recoverable	357,200	274,275
Net balance at January 1	432,568	346,080
Incurred related to:
Current year	269,204	326,919
Retroactive loss portfolio transfer	0	21,700
Prior years	6,040	58,288
Total incurred	275,244	406,907
Paid related to:
Current year	101,475	113,312
Retroactive loss portfolio transfer	0	21,700
Prior years	177,571	185,407
Total paid	279,046	320,419
Net balance at December 31	428,766	432,568
Plus reinsurance recoverable	387,915	357,200
Balance at December 31	$ 816,681	$ 789,768