UNAUDITED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Available-for-sale debt securities, amortized cost	$ 5,257,264	$ 7,825,435
Held-to-maturity debt securities, fair value	$ 387,654	$ 423,226
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock issued (in shares)	176,376,675	176,172,073
Common stock outstanding (in shares)	176,376,675	176,172,073