The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph A240

-Subparagraph b(1)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

-Paragraph 2

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- Definition

The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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- Definition

The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 2

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-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.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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2005 Shares Plan Options Outstanding (Detail)																							12 Months Ended			12 Months Ended			12 Months Ended			12 Months Ended
2005 Shares Plan Options Outstanding (Detail)	Dec. 31, 2011 Stock Appreciation Rights ZAR	Dec. 31, 2010 Stock Appreciation Rights ZAR	Jun. 30, 2010 Stock Appreciation Rights ZAR	Jun. 30, 2009 Stock Appreciation Rights ZAR	Dec. 31, 2011 2005 Share Plan South Africa Rand ZAR	Dec. 31, 2010 2005 Share Plan South Africa Rand ZAR	Jun. 30, 2010 2005 Share Plan South Africa Rand ZAR	Jun. 30, 2009 2005 Share Plan South Africa Rand ZAR	Jun. 30, 2008 2005 Share Plan South Africa Rand ZAR	Dec. 31, 2011 2005 Share Plan U.S. Dollar USD ($)	Dec. 31, 2010 2005 Share Plan U.S. Dollar USD ($)	Jun. 30, 2010 2005 Share Plan U.S. Dollar USD ($)	Jun. 30, 2009 2005 Share Plan U.S. Dollar USD ($)	Jun. 30, 2008 2005 Share Plan U.S. Dollar USD ($)	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Year	Dec. 31, 2010 2005 Share Plan Stock Appreciation Rights	Jun. 30, 2010 2005 Share Plan Stock Appreciation Rights	Jun. 30, 2009 2005 Share Plan Stock Appreciation Rights	Jun. 30, 2008 2005 Share Plan Stock Appreciation Rights	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights South Africa Rand ZAR	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights U.S. Dollar USD ($)	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 1 Year	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 1 South Africa Rand ZAR	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 1 U.S. Dollar USD ($)	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 2 Year	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 2 South Africa Rand ZAR	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 2 U.S. Dollar USD ($)	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 3 Year	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 3 South Africa Rand ZAR	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 3 U.S. Dollar USD ($)	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 4 Year	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 4 South Africa Rand ZAR	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights Range 4 U.S. Dollar USD ($)
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding options, Price range, lower limit																							60.00	$ 7.38		85.00	$ 10.46		110.00	$ 13.53		135.00	$ 16.61
Outstanding options, Contractual life (in years)															3.83							2.95			3.50			4.28			6.01
Outstanding options, Price range, upper limit																							84.99	$ 10.45		109.99	$ 13.52		134.99	$ 16.60		159.99	$ 19.68
Outstanding options, Number of options															5,030,143	5,270,597	5,660,272	4,609,626	3,837,937			3,400			3,000,076			1,991,517			35,150
Outstanding options, Weighted average exercise price	119.17	93.89	90.84	108.90	107.91	105.53	106.00	111.50	112.73	$ 13.27	$ 15.63	$ 14.00	$ 13.83	$ 14.09						107.91	$ 13.27		69.48	$ 8.55		99.82	$ 12.28		120.20	$ 14.79		136.29	$ 16.76