Stock-Based Compensation and Shares Repurchases - Recognized Stock-Based Compensation Expense within Selling, General and Administrative Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2018	May 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted stock and stock appreciation rights	$ 13,457	$ 16,829	$ 69,916	$ 28,539
Employee stock purchase plan	1,581	1,521	5,368	4,838
Other	0	0	7,538	0
Total	$ 15,038	$ 18,350	$ 82,822	$ 33,377