Premiums and Reinsurance Related Information - Premiums and Reinsurance, Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 28,236	$ 24,264	$ 25,218	$ 22,883
Cumulative effect adjustment resulting from changes in accounting principles	30,557	24,808	30,557	24,808
Provision for expected credit losses	2,321	544	5,339	1,925
Allowance for expected credit losses, end of period	30,557	24,808	30,557	24,808
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	7,655	7,373	7,713	7,801
Cumulative effect adjustment resulting from changes in accounting principles	7,744	7,283	7,744	7,283
Reinsurance Recoverable, Credit Loss Expense (Reversal)	89	(90)	31	(518)
Allowance for expected credit losses, end of period	$ 7,744	$ 7,283	$ 7,744	$ 7,283