Subsequent Event - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Sep. 19, 2012	Apr. 30, 2012	Oct. 27, 2011	Aug. 02, 2011	Oct. 29, 2010	Oct. 08, 2009	Aug. 31, 2013 Subsequent Event
Subsequent Event [Line Items]
Loan agreement maximum borrowing capacity	$ 80.0	$ 80.0	$ 60.0	$ 40.0	$ 20.0	$ 10.0	$ 3.0	$ 100.0

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant