Securities - Contractual maturities of debt securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized Cost
Due in one year or less	$ 14,709
Due after one but within five years	45,896
Due after five but within ten years	88,156
Due after ten years	412,092
Total of securities having specified maturity period	560,853
Mortgage-backed securities and collateralized mortgage obligations	967,085
TOTAL	1,527,938	$ 1,344,790
Fair Value
Due in one year or less	14,645
Due after one but within five years	44,462
Due after five but within ten years	81,746
Due after ten years	354,494
Total of securities having specified maturities period	495,347
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	836,638
Fair Value	$ 1,331,985	$ 1,364,734