Cash Flows (Summary Of Non-Cash Activities And Other Supplemental Data) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Increase in capital lease obligations	$ 0	$ 10,982	$ 6,191
Treasury stock not yet settled	995	10,454	0
Exercise of RLJE Warrants	5,001	0	0
Capital expenditures incurred but not yet paid	5,889	6,988	6,423
Cash interest paid—continuing operations	110,650	128,319	120,394
Income taxes paid, net—continuing operations	$ 219,425	$ 106,476	$ 186,725