Statutory Information - Statutory financial information of insurance subsidiaries (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statutory Capital [Abstract]
Statutory net income	$ 295,811	$ 65,201	$ 305,857
Statutory policyholders' surplus	1,220,714	1,339,509	1,619,069
Contingency reserve	$ 4,126,604	$ 3,585,864	$ 3,021,055