Contingencies (Detail) (Threatened Litigation [Member], Proposed Foreign Corrupt Practices Act Settlement [Member], USD $) In Millions, unless otherwise specified			9 Months Ended
Oct. 31, 2013	Apr. 30, 2013	Oct. 31, 2013 Minimum [Member] Scenario, Forecast [Member]	Oct. 31, 2013 Maximum [Member] Scenario, Forecast [Member]
Loss Contingencies [Line Items]
Loss contingency liability accrued, representing the initial estimate of the amount that may be required to disgorge to the SEC and interest		$ 4.8
Estimated Settlement Cost			10.4	16.0
Reserve for the settlement	$ 10.4	$ 4.8

Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.25)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_LitigationReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant