Investment Securities - Schedule of Maturities of Investment Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Available-for-sale, amortized cost, one year or less	$ 10,889
Available-for-sale, amortized cost, after one through five years	104,625
Available-for-sale, amortized cost, after five through ten years	138,009
Available-for-sale, amortized cost, after ten years	1,023,532
Available-for-sale, amortized cost, securities not due on a single maturity date	2,446,711
Available-for-sale, amortized cost, other securities (no maturity)	208
Amortized Cost	3,723,974	$ 2,852,774
Available-for-sale, fair value, one year or less	10,792
Available-for-sale, fair value, after one through five years	104,255
Available-for-sale, fair value, after five through ten years	130,883
Available-for-sale, fair value, after ten years	823,546
Available-for-sale, fair value, securities not due on a single maturity date	2,249,593
Available-for-sale, fair value, other securities (no maturity)	208
Available-for-sale, fair value, total	$ 3,319,277	$ 2,529,426