Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30, 31

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Name:	us-gaap_StockRepurchasedDuringPeriodValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Stockholders' Equity - Additional Information (Detail) - May 2014 Authorized Amount - USD ($)	6 Months Ended	12 Months Ended
	Sep. 30, 2015	Mar. 31, 2015	May. 31, 2014
Stockholders Equity Note [Line Items]
Amount remaining authorized to repurchase shares	$ 100,000,000
Number of Shares Repurchased	0
Shares repurchased, value		$ 100,000,000
Maximum
Stockholders Equity Note [Line Items]
Amount authorized to repurchase shares			$ 200,000,000