Premiums and Reinsurance Related Information - Premiums and Reinsurance, Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 28,236	$ 32,353	$ 30,660	$ 25,218
Cumulative effect adjustment resulting from changes in accounting principles	32,770	30,557	32,770	30,557
Change in expected credit losses	417	2,321	2,110	5,339
Allowance for expected credit losses, end of period	32,770	30,557	32,770	30,557
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	8,703	7,655	8,064	7,713
Cumulative effect adjustment resulting from changes in accounting principles	9,365	7,744	9,365	7,744
Reinsurance Recoverable, Credit Loss Expense (Reversal)	662	89	1,301	31
Allowance for expected credit losses, end of period	$ 9,365	$ 7,744	$ 9,365	$ 7,744