Other Comprehensive Loss - Summary of Accumulated Other Comprehensive loss ("AOCL") (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Available for sale securities, before tax amount
Unrealized holding losses, before tax amount	$ (11,016)	$ (3,923)
Interest rate swaps designated as cash flow hedges, before tax amount
Unrealized holding losses, before tax amount	(1,700)	(447)
Reclassification adjustment for losses recognized in net income, before tax amount	(614)	(630)
Defined benefit retirement plans, before tax amount
Net change in retirement liability, before tax amount		11
Total other comprehensive income/(loss), before tax amount	(13,330)	(4,989)
Available for sale securities, tax (expense) or benefit
Unrealized holding losses, tax (expense) or benefit	2,789	1,036
Interest rate swaps designated as cash flow hedges, tax (expense) or benefit
Unrealized holding losses, tax (expense) or benefit	474	125
Reclassification adjustment for (losses) gains recognized in net income, tax (expense) or benefit	173	176
Defined benefit retirement plans, tax (expense) or benefit
Net change in retirement liability, tax (expense) or benefit		(3)
Total other comprehensive income/(loss), tax (expense) or benefit	3,436	1,334
Available for sale securities
Unrealized holding losses, net-of-tax amount	(8,227)	(2,887)
Interest rate swaps designated as cash flow hedges
Unrealized holding losses, net-of-tax amount	(1,226)	(322)
Reclassification adjustment for (losses) gains realized in net income	(441)	(454)
Defined benefit retirement plans
Change in retirement liabilities		8
Other comprehensive loss	$ (9,894)	$ (3,655)