Premiums and Reinsurance Related Information - Premiums and Reinsurance, Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 37,279	$ 32,770	$ 35,110	$ 30,660
Cumulative effect adjustment resulting from changes in accounting principles	38,071	33,602	38,071	33,602
Change in expected credit losses	792	832	2,961	2,942
Allowance for expected credit losses, end of period	38,071	33,602	38,071	33,602
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	10,255	9,365	8,404	8,064
Cumulative effect adjustment resulting from changes in accounting principles	8,332	9,443	8,332	9,443
Reinsurance Recoverable, Credit Loss Expense (Reversal)	(1,923)	78	(72)	1,379
Allowance for expected credit losses, end of period	$ 8,332	$ 9,443	$ 8,332	$ 9,443