Fair Value of Financial Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Jun. 30, 2011
Fair Value of Financial Instruments [Line Items]
Fair value transfer from Level 2 to level 1	$ 0	$ 0
Fair value transfer from Level 3 to level 2	$ 0.6

Amount of transfers of financial instruments classified in shareholders' equity measured on a recurring basis out of level 2 of the fair value hierarchy into level 1.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Name:	us-gaap_FairValueEquityLevel2ToLevel1TransfersAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant