Cost Method Investment - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Sep. 30, 2011	Dec. 31, 2000
Schedule of Cost-method Investments [Line Items]
Cost Method Investment, Shares acquired		1.7
Cost Method Investment, Percent of interest acquired		5.00%
Proceeds from sale of equity interest	$ 3.4
Sanju K. Bansal
Schedule of Cost-method Investments [Line Items]
Percentage of equity interest held by third party	10.00%

For investments in debt and equity securities accounted for at cost, the excess of net sale proceeds over the carrying amount of investments disposed of during the period.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph c, d

-Article 5

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 210.5-03.7(c))

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

Name:	us-gaap_CostMethodInvestmentsRealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration