Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Contractual maturities of investments in debt securities available-for-sale, Amortized Cost
Due in one year or less	$ 96,181
Due after one year through five years	1,040,653
Due after five years through ten years	17,843
Due after ten years	23,827
Mortgage-backed securities	702,499
Total debt securities available-for-sale	1,881,003	$ 1,969,171
Contractual maturities of investments in debt securities available-for-sale, Fair Value
Due in one year or less	94,493
Due after one year through five years	960,875
Due after five years through ten years	15,396
Due after ten years	24,104
Mortgage-backed securities	618,612
Total debt securities available-for-sale	1,713,480	1,775,128
Accrued interest receivable on investment securities available-for-sale	4,880	5,980
U.S. Treasury and Federal agencies securities
Contractual maturities of investments in debt securities available-for-sale, Amortized Cost
Total debt securities available-for-sale	1,052,191	1,090,743
Contractual maturities of investments in debt securities available-for-sale, Fair Value
Total debt securities available-for-sale	975,221	998,598
U.S. States and political subdivisions securities
Contractual maturities of investments in debt securities available-for-sale, Amortized Cost
Total debt securities available-for-sale	114,237	130,670
Contractual maturities of investments in debt securities available-for-sale, Fair Value
Total debt securities available-for-sale	107,875	122,762
Mortgage-backed securities - Federal agencies
Contractual maturities of investments in debt securities available-for-sale, Amortized Cost
Total debt securities available-for-sale	702,499	730,672
Contractual maturities of investments in debt securities available-for-sale, Fair Value
Total debt securities available-for-sale	618,612	637,058
Corporate debt securities
Contractual maturities of investments in debt securities available-for-sale, Amortized Cost
Total debt securities available-for-sale	11,476	16,486
Contractual maturities of investments in debt securities available-for-sale, Fair Value
Total debt securities available-for-sale	11,195	16,131
Foreign government and other securities
Contractual maturities of investments in debt securities available-for-sale, Amortized Cost
Total debt securities available-for-sale	600	600
Contractual maturities of investments in debt securities available-for-sale, Fair Value
Total debt securities available-for-sale	$ 577	$ 579