Fair Value Of Financial Instruments (Financial Assets Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2012	Aug. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 10,669	$ 11,338
Restricted cash (current)	10,351	12,850
Restricted cash (noncurrent)	7,963	8,108
Total	28,983	32,296
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	10,669	11,338
Restricted cash (current)	10,351	12,850
Restricted cash (noncurrent)	7,963	8,108
Total	28,983	32,296
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents
Restricted cash (current)
Restricted cash (noncurrent)
Total
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents
Restricted cash (current)
Restricted cash (noncurrent)
Total