Accumulated Other Comprehensive Income (AOCI) (Schedule of Items Reclassified to Statement of Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service credit	$ (1,122)	$ (1,118)	$ (2,245)	$ (2,237)
Net actuarial loss	967	1,108	1,938	2,217
Income before income taxes	53,827	44,886	92,900	82,536
Income tax effect	(14,458)	(13,446)	(25,456)	(23,486)
Net income attributable to the Company	39,201	31,397	66,938	58,980
Reclassification out of Accumulated Other Comprehensive Income | Derivative valuation adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Expense/(income) related to interest rate swaps included in Income before taxes	1,168	1,770	2,864	3,246
Income tax effect	(295)	(457)	(725)	(838)
Net income attributable to the Company	873	1,313	2,139	2,408
Reclassification out of Accumulated Other Comprehensive Income | Pension and postretirement liability adjustments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service credit	(1,122)	(1,118)	(2,245)	(2,237)
Net actuarial loss	967	1,108	1,938	2,217
Income before income taxes	(155)	(10)	(307)	(20)
Income tax effect	47	3	94	6
Net income attributable to the Company	$ (108)	$ (7)	$ (213)	$ (14)