Segments and Related Information (Reconciliation of Consolidated Income before Income Taxes to EBITDA) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
EBITDA Reconciliation:
Income before income taxes	$ 173,385	$ 145,633	$ 388,484	$ 299,405
Interest expense, net	19,297	22,330	58,178	60,183
Depreciation and amortization	55,196	54,863	174,171	156,478
EBITDA	$ 247,900	$ 222,800	$ 620,800	$ 516,100