Accumulated Other Comprehensive Loss - Reclassification from Each Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reclassification Out Of Accumulated Other Comprehensive Loss
(Losses) gains on securities transactions, net	$ (1,072)	$ 101
Tax effect	(39,314)	(39,321)
Net income	116,728	115,710
Interest expense	(22,789)	(39,131)
Amortization of actuarial net loss	23,290	18,393
Amounts Reclassified from Accumulated Other Comprehensive Loss
Reclassification Out Of Accumulated Other Comprehensive Loss
Net income	(508)	(975)
Interest expense	(542)	(915)
Amounts Reclassified from Accumulated Other Comprehensive Loss | Unrealized gains (losses) on AFS securities before tax
Reclassification Out Of Accumulated Other Comprehensive Loss
(Losses) gains on securities transactions, net	14	(59)
Tax effect	(4)	15
Net income	10	(44)
Amounts Reclassified from Accumulated Other Comprehensive Loss | Unrealized losses on derivatives (cash flow hedges) before tax
Reclassification Out Of Accumulated Other Comprehensive Loss
Tax effect	156	264
Net income	(386)	(651)
Interest expense	(542)	(915)
Amounts Reclassified from Accumulated Other Comprehensive Loss | Defined benefit pension plan
Reclassification Out Of Accumulated Other Comprehensive Loss
Tax effect	51	108
Net income	(132)	(280)
Amortization of actuarial net loss	$ (183)	$ (388)