Accounting Policies - Joint Ventures (Details 10) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Revenues	$ 5,680,733	$ 5,532,750	$ 5,336,776
Operating income	534,219	544,925	$ 481,220
Receivables	946,741	873,986
Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	1,300	425
Income (Loss) from Equity Method Investments	892	(32)
Joint Venture, Proportionate Consolidation
Schedule of Equity Method Investments [Line Items]
Revenues	14,700	69,700
Operating income	4,700	20,600
Receivables	$ 1,200	$ 1,800
Minimum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	33.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	50.00%