Segments and Related Information (Reconciliation of Consolidated Income before Income Taxes to EBITDA) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
EBITDA Reconciliation:
Income before income taxes	$ 425,164	$ 510,939	$ 365,303
Interest expense, net	59,629	77,026	82,571
Depreciation	258,841	212,485	192,332
Amortization of intangible assets	38,910	22,997	20,598
EBITDA	$ 782,500	$ 823,400	$ 660,800