Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Net Income Per Share Data - Additional Information (Detail) - USD ($) shares in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Nov. 05, 2014
Earnings Loss Per Share [Line Items]
Anti-dilutive outstanding stock options	0.1	0.1
Accelerated Share Repurchase Program [Member]
Earnings Loss Per Share [Line Items]
Maximum payments for repurchase of common stock			$ 25,300,000