Derivative Financial Instruments and Hedging Activities Gains (Losses) Included in Other Comprehensive Income on Derivatives Accounted for as Hedging Instruments, Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate derivatives	$ 389	$ 0	$ (3,907)	$ (10,580)