Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from AOCI (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and fees on loans and leases	$ 557,195			$ 356,371			$ 1,189,707	$ 1,040,421
Provision (benefit) for income taxes	2,210			35,796			19,757	97,321
Amounts reclassified from AOCI	(539,038)	$ (56,665)	$ (16,472)	(113,943)	$ (113,742)	$ (103,405)	(612,175)	(331,090)
All other expense	68,131			61,238			160,971	150,720
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	1,395			3,091			4,176	9,100
Reclassification out of Accumulated Other Comprehensive Income | Securities AFS
Accumulated Other Comprehensive Income (Loss) [Line Items]
Securities gains (losses), net	1,323			0			1,323	267
Provision (benefit) for income taxes	(320)			0			(320)	(66)
Amounts reclassified from AOCI	1,003			0			1,003	201
Reclassification out of Accumulated Other Comprehensive Income | Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and fees on loans and leases	(2,807)			1,313			(5,084)	5,012
Provision (benefit) for income taxes	679			(324)			1,231	(1,239)
Amounts reclassified from AOCI	(2,128)			989			(3,853)	3,773
Reclassification out of Accumulated Other Comprehensive Income | Pension and Post-retirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision (benefit) for income taxes	(805)			(690)			(2,244)	(1,683)
Amounts reclassified from AOCI	2,520			2,102			7,026	5,126
All other expense	$ 3,325			$ 2,792			$ 9,270	$ 6,809