Accumulated other comprehensive income table (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment	[1]		$ 1,553
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		$ 40,695	18,169	$ (1,173)
Total other comprehensive income (loss)		(38,512)	22,526	19,342
Ending Balance		2,183	40,695	18,169
Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		13,255	4,398	(5,947)
Total other comprehensive income (loss)		(22,922)	8,857	10,345
Ending Balance		(9,667)	13,255	4,398
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Total other comprehensive income (loss)		(19,139)
Unrealized Gain (Loss) on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		33,276	16,479	6,148
Total other comprehensive income (loss)			16,797	10,331
Ending Balance		14,137	33,276	16,479
Defined Benefit Postretirement Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		(5,836)	(2,708)	(1,374)
Total other comprehensive income (loss)		3,549	(3,128)	(1,334)
Ending Balance		(2,287)	(5,836)	(2,708)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Total other comprehensive income (loss)		$ (38,512)	$ 22,526	$ 19,342

[1] Represents adjustment needed to reflect the cumulative impact on retained earnings pursuant to the Company's adoption of Accounting Standards Update 2016-13. The adjustment presented includes $1.1 million ($817,000, net of tax) attributable to the change in accounting methodology for estimating the allowance for credit losses and $1.0 million ($736,000, net of tax) related to the reserve for unfunded commitments resulting from the Company's adoption of the standard. Amount shown in the table above is presented net of tax.