Premiums and Reinsurance Related Information - Premiums and Reinsurance, Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 30,557	$ 24,808	$ 25,218	$ 22,883
Cumulative effect adjustment resulting from changes in accounting principles	30,578	23,676	30,578	23,676
Change in expected credit losses	21	(1,132)	5,360	793
Allowance for expected credit losses, end of period	30,578	23,676	30,578	23,676
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	7,744	7,283	7,713	7,801
Cumulative effect adjustment resulting from changes in accounting principles	7,999	7,277	7,999	7,277
Reinsurance Recoverable, Credit Loss Expense (Reversal)	255	(6)	286	(524)
Allowance for expected credit losses, end of period	$ 7,999	$ 7,277	$ 7,999	$ 7,277