Derivative Instruments - Additional Information (Detail) (Foreign Exchange Forward, USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Derivative outstanding	0	$ 0
Maximum
Derivative [Line Items]
Term of derivative contracts	90 days

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Name:	us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant