Income Taxes (Schedule Of Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Components of Deferred Tax Assets [Abstract]
Allowance for doubtful accounts	$ 9,701	$ 9,054
Operating loss and tax credit carryforwards	18,020	24,101
Compensation and employee benefits	49,136	28,305
Decommissioning liabilities	28,246	39,638
Other	47,353	35,005
Deferred tax assets, gross	152,456	136,103
Net deferred tax assets	152,456	136,103
Components of Deferred Tax Liabilities [Abstract]
Property, plant and equipment	650,778	317,033
Notes receivable	14,085	25,599
Goodwill and other intangible assets	145,296	22,432
Deferred revenue on long-term contracts	4,329	47,341
Other	48,992	21,987
Deferred tax liabilities	863,480	434,392
Net deferred tax liability	$ 711,024	$ 298,289