Allowance for Expected Credit Losses - Balances of Premiums Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accounts Receivable, after Allowance for Credit Loss [Abstract]
Balance, beginning of period	$ 167,096	$ 170,915	$ 170,953	$ 179,147
Balance, end of period	182,835	183,222	182,835	183,222
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	1,733	2,184	1,808	1,754
Current period change for expected credit losses	313	331	714	2,099
Writeoffs of uncollectable accounts receivable	(369)	(323)	(845)	(1,661)
Balance, end of period	$ 1,677	$ 2,192	$ 1,677	$ 2,192