Fair Value Of Financial Instruments (Financial Assets Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2013	Aug. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 19,976	$ 7,784
Restricted cash (current)	8,899	10,200
Restricted cash (noncurrent)	7,760	7,903
Total	36,635	25,887
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	19,976	7,784
Restricted cash (current)	8,899	10,200
Restricted cash (noncurrent)	7,760	7,903
Total	36,635	25,887
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