Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2012	May 31, 2011
Revenue Recognition
Unbilled accounts receivable related to a defense supply chain support agreement	$ 36,218	$ 28,867
Cost in excess of amount billed	$ 27,872	$ 19,404
Minimum
Principles of Consolidation
Common stock ownership for equity method accounting (as a percent)	20.00%
Maximum
Principles of Consolidation
Common stock ownership for equity method accounting (as a percent)	50.00%

Amount included in cost of uncompleted contracts in excess of related billings, or unbilled accounts receivable, which is expected to be collected after one year from the date of the balance sheet.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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- Definition

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

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