Securities - Contractual maturities of debt securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Amortized Cost
Due in one year or less	$ 8,545		$ 8,545
Due after one but within five years	44,994		44,994
Due after five but within ten years	108,667		108,667
Due after ten years	369,129		369,129
Total of securities having specified maturity period	531,335		531,335
Mortgage-backed securities and collateralized mortgage obligations	837,185		837,185
Amortized Cost	1,368,520		1,368,520		$ 1,412,498
Fair Value
Due in one year or less	8,472		8,472
Due after one but within five years	43,141		43,141
Due after five but within ten years	104,810		104,810
Due after ten years	327,821		327,821
Total of securities having specified maturities period	484,244		484,244
Mortgage-backed securities and collateralized mortgage obligations	721,507		721,507
TOTAL	1,205,751		1,205,751		$ 1,259,137
Gains and losses from investment sales/calls realized	$ 0	$ 0	$ 0	$ 0