Financial Derivatives - Summary of Amounts of Gain (Loss) on Interest Rate Derivative Instruments Recognized in Interest Expense, Financing costs and Other (Detail) $ in Thousands	12 Months Ended
Sep. 30, 2017 USD ($)
Not Designated as Hedging Instrument [Member] \| Interest Rate Swaps [Member]
Derivative [Line Items]
Gain (loss) on interest rate derivative instruments	$ (388)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

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