Equity impact of common stock cash dividends declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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

Dividends and Stock Repurchase Program - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended		1 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010	May 20, 2011 Sixth Repurchase Program	Dec. 31, 2011 Sixth Repurchase Program	Nov. 02, 2011 Seventh Repurchase Program	Dec. 31, 2011 Seventh Repurchase Program	Jun. 30, 2012 May 14, 2012
Share Repurchases [Line Items]
Dividend paid, recorded as reduction to retained earnings	$ 19,878,000	$ 16,701,000	$ 14,250,000					$ 9,794,000
Authorized amount for repurchase				$ 100,000,000		$ 100,000,000
Stock repurchase program, expiry date					2013-06-30		2013-12-31