Allowance for Expected Credit Losses - Balances of Premiums Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Balance, beginning of period	$ 182,835	$ 183,222	$ 170,953	$ 179,147
Balance, end of period	187,973	183,774	187,973	183,774
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	1,677	2,192	1,808	1,754
Current period change for expected credit losses	312	370	1,026	2,469
Writeoffs of uncollectable accounts receivable	(400)	(153)	(1,245)	(1,814)
Balance, end of period	$ 1,589	$ 2,409	$ 1,589	$ 2,409