Derivative Financial Instruments - Summary of Effects of Derivatives not Designated as Hedging Instuments on Condensed Consolidated Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jan. 31, 2018	Jan. 31, 2018
Derivative Instruments Gain Loss [Line Items]
Effects of derivative instruments	$ 3,024	$ 3,873
Derivative Instruments – Interest Rate Swaps \| Derivative Fair Vale Gain \| Not Designated As Hedging Instruments
Derivative Instruments Gain Loss [Line Items]
Effects of derivative instruments	$ 3,024	$ 3,873

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959

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