Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.3-04)

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

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-Name Accounting Standards Codification

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-Name Accounting Principles Board Opinion (APB)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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-Name Accounting Standards Codification

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

Shareholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended			3 Months Ended
	Jun. 14, 2012	May 09, 2012	Sep. 15, 2011	Jun. 30, 2012	Jun. 30, 2011
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, maximum authorized amount			$ 100,000,000
Number of shares purchased pursuant to tender offer	122,578	61,000,000
Stock repurchase program, number of shares purchased	2,913,464
Stock repurchase program, price per share of shares purchased	$ 21.75			$ 21.70	$ 22.29
Stock repurchase program, value of shares purchased	$ 63,367,842
Percentage of outstanding ordinary shares offered	2.00%