Income Taxes (Summary of Valuation Allowance) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
May 31, 2014	May 31, 2013
Movement in Valuation Allowance [Roll Forward]
Balance at beginning of period	$ (12,789)	$ (9,054)
Additions	(1,701)	(7,391)
Subtractions	1,132	3,656
Balance at end of period	$ (13,358)	$ (12,789)

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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