Accumulated Other Comprehensive Income (AOCI) (Schedule of Items Reclassified to Statement of Income) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Expense/(income) related to interest rate swaps included in Income before taxes		$ 4,424	$ 5,016
Total pretax amount reclassified		20,048	36,884
Income tax effect		12,454	7,476
Effect on net income due to items reclassified from Accumulated Other Comprehensive Income		(9,109)	(29,190)
Prior service credit		(1,114)	(1,105)
Net actuarial loss		1,244	1,121
Reclassification out of Accumulated Other Comprehensive Income [Member] | Derivative valuation adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Expense/(income) related to interest rate swaps included in Income before taxes	[1]	407	(452)
Income tax effect		(104)	115
Effect on net income due to items reclassified from Accumulated Other Comprehensive Income		303	(337)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension and postretirement liability adjustments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total pretax amount reclassified	[2]	130	16
Income tax effect		(32)	(5)
Effect on net income due to items reclassified from Accumulated Other Comprehensive Income		$ 98	$ 11

[1] Included in Interest expense, net are payments related to the interest rate swap agreements and amortization of swap buyouts (see Notes 15 and 16).

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 4).