Summary of Significant Accounting Policies - Summary of Deferred Policy Acquisition Cost Amortization and Net Advertising Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Deferred policy acquisition cost amortization	$ 633,385	$ 627,788	$ 602,085
Net advertising expense	$ 50,100	$ 37,700	$ 42,200