Other Comprehensive Income (Loss) - Changes in the Components of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	$ (6,613)	$ 18,423
Total other comprehensive income (loss), tax expense (benefit)	(1,684)	4,686
Other comprehensive (loss) income, net of tax	(4,929)	13,737
Securities available for sale:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	(20,044)	22,389
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(5,101)	5,695
Other comprehensive income (loss), before reclassifications, net of tax	(14,943)	16,694
Reclassification from AOCI, pre-tax	(1,357)
Reclassification from AOCI, tax expense (benefit)	(345)
Reclassification from AOCI, net of tax	(1,012)
Total other comprehensive income (loss), pre-tax	(21,401)	22,389
Total other comprehensive income (loss), tax expense (benefit)	(5,446)	5,695
Other comprehensive (loss) income, net of tax	(15,955)	16,694
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	14,734
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	3,750
Other comprehensive income (loss), before reclassifications, net of tax	10,984
Total other comprehensive income (loss), pre-tax	14,734
Total other comprehensive income (loss), tax expense (benefit)	3,750
Other comprehensive (loss) income, net of tax	10,984
Amortization of net actuarial loss recognized in net periodic pension cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	54	62
Reclassification from AOCI, tax expense (benefit)	12	16
Reclassification from AOCI, net of tax	42	46
Total defined benefit pension and post-retirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	54	62
Total other comprehensive income (loss), tax expense (benefit)	12	16
Other comprehensive (loss) income, net of tax	$ 42	46
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax		(4,028)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)		(1,025)
Other comprehensive income (loss), before reclassifications, net of tax		(3,003)
Total other comprehensive income (loss), pre-tax		(4,028)
Total other comprehensive income (loss), tax expense (benefit)		(1,025)
Other comprehensive (loss) income, net of tax		$ (3,003)