Supplemental Disclosure of Cash Flow Information (Parenthetical) (Detail)	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
8.875% Senior Notes
Supplemental Cash Flow Information [Abstract]
Interest on senior notes	8.875%	8.875%	8.875%

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant