Accumulated other comprehensive income table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ (114,827)	$ (163,084)	$ 2,183
Total other comprehensive income (loss)	24,820	48,257	(165,267)
Ending Balance	(90,007)	(114,827)	(163,084)
Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(96,231)	(128,657)	(9,667)
Total other comprehensive income (loss)	16,743	32,426	(118,990)
Ending Balance	(79,488)	(96,231)	(128,657)
Unrealized Gain (Loss) on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(20,575)	(36,630)	14,137
Total other comprehensive income (loss)	6,713	16,055	(50,767)
Ending Balance	(13,862)	(20,575)	(36,630)
Defined Benefit Postretirement Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	1,979	2,203	(2,287)
Total other comprehensive income (loss)	1,364	(224)	4,490
Ending Balance	3,343	1,979	2,203
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Total other comprehensive income (loss)	$ 24,820	$ 48,257	$ (165,267)