Other Comprehensive Income (Loss) - Changes in the Components of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	$ (11,476)			$ 2,160			$ (19,282)	$ 23,052
Total other comprehensive income (loss), tax expense (benefit)	(2,920)			549			(4,908)	5,866
Other comprehensive (loss) income, net of tax	(8,556)	$ (889)	$ (4,929)	1,611	$ 1,838	$ 13,737	(14,374)	17,186
Securities available for sale:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	(12,408)			519			(27,487)	26,404
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(3,158)			131			(6,996)	6,719
Other comprehensive income (loss), before reclassifications, net of tax	(9,250)			388			(20,491)	19,685
Reclassification from AOCI, pre-tax	(764)						(2,121)	(31)
Reclassification from AOCI, tax expense (benefit)	(194)						(539)	(8)
Reclassification from AOCI, net of tax	(570)						(1,582)	(23)
Total other comprehensive income (loss), pre-tax	(13,172)			519			(29,608)	26,373
Total other comprehensive income (loss), tax expense (benefit)	(3,352)			131			(7,535)	6,711
Other comprehensive (loss) income, net of tax	(9,820)			388			(22,073)	19,662
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	1,629						10,129	(3,516)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	414						2,578	(895)
Other comprehensive income (loss), before reclassifications, net of tax	1,215						7,551	(2,621)
Total other comprehensive income (loss), pre-tax	1,629						10,129	(3,516)
Total other comprehensive income (loss), tax expense (benefit)	414						2,578	(895)
Other comprehensive (loss) income, net of tax	1,215						7,551	(2,621)
Amortization of net actuarial loss recognized in net periodic pension cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	67			65			197	195
Reclassification from AOCI, tax expense (benefit)	18			17			49	50
Reclassification from AOCI, net of tax	49			48			148	145
Total defined benefit pension and post-retirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	67			65			197	195
Total other comprehensive income (loss), tax expense (benefit)	18			17			49	50
Other comprehensive (loss) income, net of tax	$ 49			48			$ 148	$ 145
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax				1,576
Other comprehensive income (loss) before reclassifications, tax expense (benefit)				401
Other comprehensive income (loss), before reclassifications, net of tax				1,175
Total other comprehensive income (loss), pre-tax				1,576
Total other comprehensive income (loss), tax expense (benefit)				401
Other comprehensive (loss) income, net of tax				$ 1,175