Derivative Financial Instruments and Hedging Activities - Pretax Gains (Losses) Recorded in Other Comprehensive Income Relating to Cash Flow Hedges (Details) - USD ($) $ in Thousands	12 Months Ended
Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest rate derivatives	$ 178	$ 0	$ (10,070)

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration