Components of Other Comprehensive Income/(loss) - Schedule of Reclassification from AOCI (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Debt securities gains/(losses), net	$ 0	$ 0	$ (267)	$ 52
Provision/(benefit) for income taxes	35,796	83,925	97,321	133,553
Amounts reclassified from AOCI	3,091	2,906	9,100	6,521
Interest and fees on loans	356,371	331,000	1,040,421	954,467
All other expense (Note 8)	39,677	25,701	88,674	112,032
Securities AFS
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0	0	201	(39)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	989	771	3,773	1,079
Pension and Post-retirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	2,102	2,135	5,126	5,481
Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	3,091	2,906	9,100	6,521
Reclassification out of Accumulated Other Comprehensive Income \| Securities AFS
Accumulated Other Comprehensive Income (Loss) [Line Items]
Debt securities gains/(losses), net	0	0	267	(52)
Provision/(benefit) for income taxes	0	0	(66)	13
Amounts reclassified from AOCI	0	0	201	(39)
Reclassification out of Accumulated Other Comprehensive Income \| Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Provision/(benefit) for income taxes	(324)	(253)	(1,239)	(354)
Amounts reclassified from AOCI	989	771	3,773	1,079
Interest and fees on loans	1,313	1,024	5,012	1,433
Reclassification out of Accumulated Other Comprehensive Income \| Pension and Post-retirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	2,102	2,135	5,126	5,481
All other expense (Note 8)	2,792	2,836	6,809	7,280
Reclassification from AOCI, current period, tax	$ (690)	$ (701)	$ (1,683)	$ (1,799)

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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