Segments (Details) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Selected financial information by reportable operating segment
Revenues	$ 640,013	$ 560,235	$ 1,743,742	$ 1,616,235
Adjusted EBITDA	154,273	125,077	406,770	371,974
Capital Expenditures	40,881	31,297	126,183	88,256
U.S. [Member]
Selected financial information by reportable operating segment
Revenues	441,334	400,277	1,216,679	1,199,856
Adjusted EBITDA	110,285	87,778	289,091	273,731
Capital Expenditures	17,871	11,564	57,316	47,571
International [Member]
Selected financial information by reportable operating segment
Revenues	201,637	161,492	534,828	420,404
Adjusted EBITDA	43,988	37,299	117,679	98,243
Capital Expenditures	23,010	19,733	68,867	40,685
Eliminations [Member]
Selected financial information by reportable operating segment
Revenues	$ (2,958)	$ (1,534)	$ (7,765)	$ (4,025)

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 17

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration