Share-Based Compensation Plans (Details 3) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Range of exercise price
Share options outstanding and share options exercisable
Share options, outstanding (in shares)	5,611
Share options exercisable (in shares)	5,117
Range of exercise price, $ 14.71 - $ 22.86
Share options outstanding and share options exercisable
Share options, range of exercise prices, low end of the range (in dollars per share)	$ 14.71
Share options, range of exercise prices, high end of the range (in dollars per share)	$ 22.86
Share options, outstanding (in shares)	1,747
Weighted average remaining contractual life of share options outstanding	2 years 25 days
Weighted average exercise price of share options outstanding (in dollars per share)	$ 21.72
Share options exercisable (in shares)	1,747
Weighted average remaining contractual life of share options exercisable (in years)	2 years 25 days
Weighted average exercise price of share options exercisable (in dollars per share)	$ 21.72
Range of exercise price, $ 22.87 - $ 25.51
Share options outstanding and share options exercisable
Share options, range of exercise prices, low end of the range (in dollars per share)	$ 22.87
Share options, range of exercise prices, high end of the range (in dollars per share)	$ 25.51
Share options, outstanding (in shares)	331
Weighted average remaining contractual life of share options outstanding	2 years 5 months 5 days
Weighted average exercise price of share options outstanding (in dollars per share)	$ 25.40
Share options exercisable (in shares)	331
Weighted average remaining contractual life of share options exercisable (in years)	2 years 5 months 5 days
Weighted average exercise price of share options exercisable (in dollars per share)	$ 25.40
Range of exercise price, $ 25.52 - $ 32.53
Share options outstanding and share options exercisable
Share options, range of exercise prices, low end of the range (in dollars per share)	$ 25.52
Share options, range of exercise prices, high end of the range (in dollars per share)	$ 32.53
Share options, outstanding (in shares)	675
Weighted average remaining contractual life of share options outstanding	1 year 8 months 26 days
Weighted average exercise price of share options outstanding (in dollars per share)	$ 27.30
Share options exercisable (in shares)	675
Weighted average remaining contractual life of share options exercisable (in years)	1 year 8 months 26 days
Weighted average exercise price of share options exercisable (in dollars per share)	$ 27.30
Range of exercise price, $ 32.54 - $ 36.88
Share options outstanding and share options exercisable
Share options, range of exercise prices, low end of the range (in dollars per share)	$ 32.54
Share options, range of exercise prices, high end of the range (in dollars per share)	$ 36.88
Share options, outstanding (in shares)	631
Weighted average remaining contractual life of share options outstanding	2 years 11 months 26 days
Weighted average exercise price of share options outstanding (in dollars per share)	$ 35.89
Share options exercisable (in shares)	482
Weighted average remaining contractual life of share options exercisable (in years)	2 years 6 months 25 days
Weighted average exercise price of share options exercisable (in dollars per share)	$ 35.73
Range of exercise price, $ 36.89 - $ 43.44
Share options outstanding and share options exercisable
Share options, range of exercise prices, low end of the range (in dollars per share)	$ 36.89
Share options, range of exercise prices, high end of the range (in dollars per share)	$ 43.44
Share options, outstanding (in shares)	1,393
Weighted average remaining contractual life of share options outstanding	2 years 9 months 22 days
Weighted average exercise price of share options outstanding (in dollars per share)	$ 39.50
Share options exercisable (in shares)	1,238
Weighted average remaining contractual life of share options exercisable (in years)	2 years 4 months 13 days
Weighted average exercise price of share options exercisable (in dollars per share)	$ 39.58
Range of exercise price, $ 43.45 - $ 52.93
Share options outstanding and share options exercisable
Share options, range of exercise prices, low end of the range (in dollars per share)	$ 43.45
Share options, range of exercise prices, high end of the range (in dollars per share)	$ 52.93
Share options, outstanding (in shares)	834
Weighted average remaining contractual life of share options outstanding	3 years 9 months 14 days
Weighted average exercise price of share options outstanding (in dollars per share)	$ 46.54
Share options exercisable (in shares)	644
Weighted average remaining contractual life of share options exercisable (in years)	3 years 3 months 25 days
Weighted average exercise price of share options exercisable (in dollars per share)	$ 45.64

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.

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- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

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- Definition

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

+ References

+ Details

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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 number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ 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)(c)

-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 (c)(iii)

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

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ 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)-(ii)

-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, 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.

+ Details

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

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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

+ Details

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