Segment Data (Schedule Of Operating Segment Results) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Revenue	$ 761,326	$ 789,208	$ 1,412,609	$ 1,439,422
Direct operating expenses (excludes depreciation and amortization)	406,895	415,472	800,948	806,852
Selling, general and admin expenses (excludes depreciation and amortization)	132,285	142,937	285,434	266,117
Depreciation and amortization	99,668	105,600	192,005	207,930
Corporate expenses (excludes depreciation and amortization)	27,838	23,038	52,148	45,021
Other operating income - net	2,746	4,300	6,749	9,102
Operating income (loss)	97,386	106,461	88,823	122,604
Capital expenditures	74,806	59,413	130,796	105,774
Share-based compensation expense	2,154	2,408	5,356	5,521
Americas [Member]
Segment Reporting Information [Line Items]
Revenue	320,678	318,217	600,829	587,918
Direct operating expenses (excludes depreciation and amortization)	143,185	141,010	287,595	276,960
Selling, general and admin expenses (excludes depreciation and amortization)	44,699	49,035	97,278	98,593
Depreciation and amortization	48,567	50,322	91,525	98,944
Operating income (loss)	84,227	77,850	124,431	113,421
Capital expenditures	33,780	34,562	59,116	65,477
Share-based compensation expense	1,240	1,674	3,172	3,842
International [Member]
Segment Reporting Information [Line Items]
Revenue	440,648	470,991	811,780	851,504
Direct operating expenses (excludes depreciation and amortization)	263,710	274,462	513,353	529,892
Selling, general and admin expenses (excludes depreciation and amortization)	87,586	93,902	188,156	167,524
Depreciation and amortization	50,710	55,278	99,745	108,986
Operating income (loss)	38,642	47,349	10,526	45,102
Capital expenditures	39,247	23,979	66,909	39,102
Share-based compensation expense	874	701	2,083	1,604
Corporate and Other Reconciling Items [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	391		735
Corporate expenses (excludes depreciation and amortization)	27,838	23,038	52,148	45,021
Other operating income - net	2,746	4,300	6,749	9,102
Operating income (loss)	(25,483)	(18,738)	(46,134)	(35,919)
Capital expenditures		872		1,195
Share-based compensation expense	$ 40	$ 33	$ 101	$ 75