Litigation, Indemnities and Guarantees Litigation, Indemnities and Guarantees (Details) - Apr. 30, 2015	officer claim
Commitments and Contingencies Disclosure [Abstract]
Number of class action complaints	2
Number of former officers claims filed against \| officer	2

Number of pending claims pertaining to a loss contingency.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant