Allowance for Expected Credit Losses - Balances of Premiums Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Balance, beginning of period	$ 238,563	$ 182,835	$ 192,542	$ 170,953
Balance, end of period	258,267	187,973	258,267	187,973
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	996	1,677	1,446	1,808
Current period change for expected credit losses	713	312	1,480	1,026
Writeoffs of uncollectable accounts receivable	(842)	(400)	(2,059)	(1,245)
Balance, end of period	$ 867	$ 1,589	$ 867	$ 1,589