Supplemental Guarantor Information Supplemental Guarantor Information (Level 4 Textuals) (Details)	Apr. 30, 2012
Subsidiary of Common Parent [Member]
Entity Information [Line Items]
Subsidiary of Company, Ownership Percentage by Parent	100.00%
Guarantor Subsidiaries [Member]
Entity Information [Line Items]
Subsidiary of Company, Ownership Percentage by Parent	100.00%

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant