Other Comprehensive Income (Loss) - Changes in the Components of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	$ (1,193)		$ 2,469		$ (7,806)	$ 20,892
Total other comprehensive income (loss), tax expense (benefit)	(304)		631		(1,988)	5,317
Other comprehensive (loss) income, net of tax	(889)	$ (4,929)	1,838	$ 13,737	(5,818)	15,575
Securities available for sale:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	4,965		3,496		(15,079)	25,885
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	1,263		893		(3,838)	6,588
Other comprehensive income (loss), before reclassifications, net of tax	3,702		2,603		(11,241)	19,297
Reclassification from AOCI, pre-tax			(31)		(1,357)	(31)
Reclassification from AOCI, tax expense (benefit)			(8)		(345)	(8)
Reclassification from AOCI, net of tax			(23)		(1,012)	(23)
Total other comprehensive income (loss), pre-tax	4,965		3,465		(16,436)	25,854
Total other comprehensive income (loss), tax expense (benefit)	1,263		885		(4,183)	6,580
Other comprehensive (loss) income, net of tax	3,702		2,580		(12,253)	19,274
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	(6,234)				8,500	(5,092)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(1,586)				2,164	(1,296)
Other comprehensive income (loss), before reclassifications, net of tax	(4,648)				6,336	(3,796)
Total other comprehensive income (loss), pre-tax	(6,234)				8,500	(5,092)
Total other comprehensive income (loss), tax expense (benefit)	(1,586)				2,164	(1,296)
Other comprehensive (loss) income, net of tax	(4,648)				6,336	(3,796)
Amortization of net actuarial loss recognized in net periodic pension cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	76		68		130	130
Reclassification from AOCI, tax expense (benefit)	19		17		31	33
Reclassification from AOCI, net of tax	57		51		99	97
Total defined benefit pension and post-retirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	76		68		130	130
Total other comprehensive income (loss), tax expense (benefit)	19		17		31	33
Other comprehensive (loss) income, net of tax	$ 57		51		$ 99	$ 97
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax			(1,064)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)			(271)
Other comprehensive income (loss), before reclassifications, net of tax			(793)
Total other comprehensive income (loss), pre-tax			(1,064)
Total other comprehensive income (loss), tax expense (benefit)			(271)
Other comprehensive (loss) income, net of tax			$ (793)