Basis of Presentation and Principles of Consolidation Basis of Presentation and Principles of Consolidation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 30, 2012	Apr. 30, 2011
Organization, Consolidation and Presentation of Financial Statements Line Items [Line Items]
Net income (loss) attributable to noncontrolling interest	$ (20)	$ 0
Aerostar Integrated Systems [Member]
Organization, Consolidation and Presentation of Financial Statements Line Items [Line Items]
Joint venture, ownership percentage	75.00%
Net income (loss) attributable to noncontrolling interest	(20)
Capital contribution, amount	$ 0

The portion of net Income or Loss attributable to the noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=6921930&loc=SL4573702-111684

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4J

-URI http://asc.fasb.org/extlink&oid=6922042&loc=SL4591551-111686

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 38

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 38

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph A1, A4, A5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 55

-Paragraph 4K

-URI http://asc.fasb.org/extlink&oid=6922042&loc=SL4591552-111686

+ Details

- Definition

The cash inflow contributed by noncontrolled interest that purchase additional shares or otherwise increase their ownership stake in a subsidiary of the entity.

+ References+ Details