Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Employee benefits	$ 91,474	$ 231,386
Self-insurance accruals	23,042	32,336
Domestic operating-loss carryforwards	22,461	37,818
Foreign operating-loss carryforwards	16,832	11,307
Tax-credit carryforwards	10,019	9,138
Share-based compensation	16,551	15,558
Other	11,471	13,242
Valuation allowance	(25,358)	(19,120)
Total deferred income tax assets	166,492	331,665
Property, plant and equipment	348,728	331,325
Prepaid expenses	24,401	27,626
Revenue	9,013	6,808
Other	6,967	8,798
Total deferred income tax liabilities	389,109	374,557
Net deferred tax asset (liability)	$ (222,617)	$ (42,892)