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, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	$ 1,129		$ (68,183)		$ 23,431	$ (194,440)
Total other comprehensive income (loss), tax expense (benefit)	266		(17,354)		5,855	(49,485)
Other comprehensive income (loss), net of tax	863	$ 16,713	(50,829)	$ (94,126)	17,576	(144,955)
Securities available for sale:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	(21,283)		(76,405)		(569)	(211,161)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(5,353)		(19,447)		(170)	(53,741)
Other comprehensive income (loss), before reclassifications, net of tax	(15,930)		(56,958)		(399)	(157,420)
Reclassification from AOCI, pre-tax	22,438		(220)		22,438
Reclassification from AOCI, tax expense (benefit)	5,622		(56)		5,622
Reclassification from AOCI, net of tax	16,816		(164)		16,816
Total other comprehensive income (loss), pre-tax	4,181		(76,625)		28,023	(211,480)
Total other comprehensive income (loss), tax expense (benefit)	1,043		(19,503)		7,026	(53,822)
Other comprehensive income (loss), net of tax	3,138		(57,122)		20,997	(157,658)
Amortization of unrealized holding losses on securities transferred to the held to maturity category
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	3,026				6,154	(319)
Reclassification from AOCI, tax expense (benefit)	774				1,574	(81)
Reclassification from AOCI, net of tax	2,252				4,580	(238)
Derivative instruments:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	(3,167)		8,401		(4,823)	16,957
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(806)		2,139		(1,230)	4,316
Other comprehensive income (loss), before reclassifications, net of tax	(2,361)		6,262		(3,593)	12,641
Total other comprehensive income (loss), pre-tax	(3,167)		8,401		(4,823)	16,957
Total other comprehensive income (loss), tax expense (benefit)	(806)		2,139		(1,230)	4,316
Other comprehensive income (loss), net of tax	(2,361)		6,262		(3,593)	12,641
Amortization of net actuarial loss recognized in net periodic pension cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	115		41		231	83
Reclassification from AOCI, tax expense (benefit)	29		10		59	21
Reclassification from AOCI, net of tax	86		31		172	62
Total defined benefit pension and post-retirement benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	115		41		231	83
Total other comprehensive income (loss), tax expense (benefit)	29		10		59	21
Other comprehensive income (loss), net of tax	$ 86		$ 31		$ 172	$ 62