Accumulated Other Comprehensive Loss - Reclassification from Each Component of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Reclassification Out Of Accumulated Other Comprehensive Loss
Gains (losses) on securities transactions, net	$ 323			$ 787			$ (1,058)	$ 1,263
Tax effect	(68,405)			(42,424)			(144,271)	(124,626)
Net income	178,119	$ 96,413	$ 116,728	122,580	$ 120,512	$ 115,710	391,260	358,802
Interest expense	(82,736)			(27,775)			(140,312)	(99,647)
Amortization of actuarial net loss	22,683			14,469			60,329	38,213
Amounts Reclassified from Accumulated Other Comprehensive Loss
Reclassification Out Of Accumulated Other Comprehensive Loss
Net income	(107)			(409)			(668)	(2,272)
Interest expense	21			(1,044)			(405)	(2,708)
Amounts Reclassified from Accumulated Other Comprehensive Loss | Unrealized gains on AFS securities before tax
Reclassification Out Of Accumulated Other Comprehensive Loss
Gains (losses) on securities transactions, net	16			825			30	663
Tax effect	(4)			(212)			(8)	(170)
Net income	12			613			22	493
Amounts Reclassified from Accumulated Other Comprehensive Loss | Unrealized gains (losses) on derivatives (cash flow hedges) before tax
Reclassification Out Of Accumulated Other Comprehensive Loss
Tax effect	(8)			301			112	780
Net income	13			(743)			(293)	(1,928)
Interest expense	21			(1,044)			(405)	(2,708)
Amounts Reclassified from Accumulated Other Comprehensive Loss | Defined benefit pension plan
Reclassification Out Of Accumulated Other Comprehensive Loss
Tax effect	51			109			153	326
Net income	(132)			(279)			(397)	(837)
Amortization of actuarial net loss	$ (183)			$ (388)			$ (550)	$ (1,163)