Accumulated Other Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net	$ 0	$ 249
Total before tax	64,401	17,858
Income tax provision	(12,548)	(3,230)
Net Income	51,853	14,628
Compensation and employee benefits	51,736	54,842
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains and Losses on Available-for-Sale Debt Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains, net	0	249
Total before tax	0	249
Income tax provision	0	(58)
Net Income	0	191
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains and Losses on Pension Plan Liability [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(150)	(104)
Income tax provision	35	24
Net Income	(115)	(80)
Compensation and employee benefits	(150)	(104)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized gains and losses from hedging instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	2,576	940
Income tax provision	(599)	(218)
Net Income	1,977	722
Interest income, Loans	$ 2,576	$ 940