Revenue by Significant Geographical Location, Determined by the End Customer (Detail) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 371,327	$ 332,497	$ 1,138,850	$ 950,928
UNITED STATES
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	205,579	182,732	598,236	503,193
Europe
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	87,647	71,737	279,341	220,740
Other International
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 78,101	$ 78,028	$ 261,273	$ 226,995

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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