Accumulated Other Comprehensive Income (AOCI) (Schedule of Items Reclassified to Statement of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Expense related to interest rate swaps included in Income before taxes	$ 17,391	$ 16,332	$ 19,650
Income tax effect	(47,163)	(41,831)	(44,829)
Effect on net income due to items reclassified from Accumulated Other Comprehensive Income	118,478	98,589	132,398
Pension settlements and curtailments	0	411	450
Prior service credit	(4,475)	(4,474)	(4,420)
Amortization of actuarial (loss)	4,625	5,004	4,480
Total pretax amount reclassified	165,931	139,074	178,212
Reclassification out of Accumulated Other Comprehensive Income | Derivative Valuation Adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Expense related to interest rate swaps included in Income before taxes	6,852	3,982	(1,011)
Income tax effect	(1,734)	(1,028)	259
Effect on net income due to items reclassified from Accumulated Other Comprehensive Income	5,118	2,954	(752)
Reclassification out of Accumulated Other Comprehensive Income | Pension and postretirement liability adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax effect	52	276	87
Effect on net income due to items reclassified from Accumulated Other Comprehensive Income	98	665	423
Pension settlements and curtailments	0	411	450
Prior service credit	(4,475)	(4,474)	(4,420)
Amortization of actuarial (loss)	4,625	5,004	4,480
Total pretax amount reclassified	$ 150	$ 941	$ 510