Schedule II - Condensed Financial Information of Registrant (Parent Company) - Balance Sheet Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 15, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Balance Sheet Statements Captions [Line Items]
Available-for-sale, amortized cost		$ 3,391,159	$ 3,054,391
Available-for-sale, allowance for credit losses		197	306	$ 339
Property and equipment, accumulated depreciation		$ 76,330	$ 74,279
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)		400,000,000	400,000,000
Common stock, shares issued (in shares)		137,598,560	137,140,522
Common stock, shares outstanding (in shares)		91,738,132	91,280,094
Treasury stock, shares (in shares)		45,860,428	45,860,428
Parent Company
Condensed Balance Sheet Statements Captions [Line Items]
Available-for-sale, amortized cost		$ 47,655	$ 78,431
Available-for-sale, allowance for credit losses		0	0
Property and equipment, accumulated depreciation		$ 913	$ 1,375
Common stock, par value (in dollars per share)		$ 0.01	$ 0.01
Common stock, shares authorized (in shares)		400,000,000	400,000,000
Common stock, shares issued (in shares)		137,598,560	137,140,522
Common stock, shares outstanding (in shares)		91,738,132	91,280,094
Treasury stock, shares (in shares)		45,860,428	45,860,428