Premiums and Reinsurance Related Information - Premiums and Reinsurance, Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Premium Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 35,110	$ 30,660
Cumulative effect adjustment resulting from changes in accounting principles	35,039	32,353
Change in expected credit losses	(71)	1,693
Allowance for expected credit losses, end of period	35,039	32,353
Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	8,404	8,064
Cumulative effect adjustment resulting from changes in accounting principles	9,185	8,703
Reinsurance Recoverable, Credit Loss Expense (Reversal)	781	639
Allowance for expected credit losses, end of period	$ 9,185	$ 8,703