Other Assets - Components of Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Other Assets [Abstract]
Prepaid reinsurance premiums	$ 166,652	$ 201,674
Company-owned life insurance	105,169	113,386
Loaned securities (Note 5)	79,073	103,996
Right-of-use assets	28,973	31,878
Other	34,545	32,246
Total other assets	$ 414,412	$ 483,180