Cash Flows (Summary Of Non-Cash Activities And Other Supplemental Data) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Increase in capital lease obligations	$ 10,982	$ 6,191	$ 18,747
Treasury stock not yet settled	10,454	0	0
Capital expenditures incurred but not yet paid	6,988	6,423	6,638
Promissory note payable	0	0	40,000
Cash interest paid—continuing operations	128,319	120,394	122,305
Income taxes paid, net—continuing operations	$ 106,476	$ 186,725	$ 99,772