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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.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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

Reference 3: 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

Reference 4: 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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- Definition

Weighted average price 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 Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)

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

Reference 2: 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

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

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- Definition

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.

+ References

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Summarize Information relating to Options Outstanding (Detail)														12 Months Ended						12 Months Ended
	Dec. 31, 2011 Stock Appreciation Rights ZAR	Dec. 31, 2010 Stock Appreciation Rights ZAR	Jun. 30, 2010 Stock Appreciation Rights ZAR	Dec. 31, 2012 2005 Share Plan USD ($)	Dec. 31, 2012 2005 Share Plan ZAR	Dec. 31, 2011 2005 Share Plan USD ($)	Dec. 31, 2011 2005 Share Plan ZAR	Dec. 31, 2010 2005 Share Plan USD ($)	Dec. 31, 2010 2005 Share Plan ZAR	Jun. 30, 2010 2005 Share Plan USD ($)	Jun. 30, 2010 2005 Share Plan ZAR	Jun. 30, 2009 2005 Share Plan USD ($)	Jun. 30, 2009 2005 Share Plan ZAR	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights USD ($)	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights ZAR	Dec. 31, 2011 2005 Share Plan Stock Appreciation Rights	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	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 1 USD ($)	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 1 ZAR	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 2 USD ($)	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 2 ZAR	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 3 USD ($)	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 3 ZAR	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 4 USD ($)	Dec. 31, 2012 2005 Share Plan Stock Appreciation Rights Range 4 ZAR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options, Price range, lower limit																				$ 7.00	60.00	$ 9.93	85.00	$ 12.84	110.00	$ 15.76	135.00
Outstanding options, Price range, upper limit																				$ 9.92	84.99	$ 12.83	109.99	$ 15.75	134.99	$ 18.67	159.99
Outstanding options, Number of options														4,318,909	4,318,909	5,030,143	5,270,597	5,660,272	4,609,626	3,400	3,400	2,625,234	2,625,234	1,652,471	1,652,471	37,804	37,804
Outstanding options, Weighted average exercise price	119.17	93.89	90.84	$ 12.53	107.37	$ 13.27	107.91	$ 15.63	105.53	$ 14.00	106.00	$ 13.83	111.50	$ 12.53	107.48					$ 8.11	69.48	$ 11.60	99.45	$ 13.96	119.65	$ 15.90	136.29
Outstanding options, Contractual life														3 years	3 years					1 year 11 months 12 days	1 year 11 months 12 days	2 years 6 months 7 days	2 years 6 months 7 days	3 years 8 months 19 days	3 years 8 months 19 days	5 years 4 days	5 years 4 days