Fair Value of Financial Instruments - Additional Information (Detail)	Dec. 31, 2014 USD ($)	Dec. 31, 2014 INR	Dec. 31, 2013 USD ($)	Dec. 31, 2013 GBP (£)
Fair Value Disclosures [Abstract]
Transfers of financial instruments between levels	$ 0		$ 0
Transfers of financial instruments between level 2 to level 1	0		0
Transfers of financial instruments out of level 3	0		0
Notional value of foreign currency forward	$ 10,900,000invest_DerivativeNotionalAmount	700,000,000invest_DerivativeNotionalAmount		£ 80,000,000invest_DerivativeNotionalAmount

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

Fair Value, Assets, Level 3 Transfers, Amount

+ References

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

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