Tax Benefits Related to Stock Compensation (Detail) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefit recognized in income Statement	$ 909	$ 1,533	$ 2,177	$ 3,061
Excess tax benefit realized	$ 6,457	$ 12,267	$ 14,549	$ 13,430

Reductions in the entity's income taxes that arise when compensation cost (from non-qualified equity-based compensation) recognized on the entity's tax return exceeds compensation cost from equity-based compensation recognized in financial statements. This element reduces net cash provided by operating activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A96
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=6576910&loc=d3e11374-113907

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