Increase decrease in excess tax benefits realized net.

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- Definition

Maximum percentage to return on invested capital for annual performance period.

+ References

No definition available.

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- Definition

Percentage of purchase price of the stock on lesser of the fair market value during the first day or the last day of offering period.

+ References

No definition available.

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- Definition

Disclosure of the specified period of time that a stock option gives the holder the right, but not the obligation, either to purchase (to call) or to sell (to put) a certain number of shares at a predetermined price.

+ References

No definition available.

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- Definition

Aggregate number of common shares reserved for future issuance.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 4

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.29)

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- Definition

Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(ii)

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- Definition

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-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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-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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- Definition

The weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, using a decimal to express in number of years.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph h

-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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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

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- Definition

The date when the equity-based award expires as specified in the award agreement, which may be presented in a variety of ways (for example, year, month and year, day, month and year, quarter of a year).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Paragraph 2

-Subparagraph (a)(2)

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- Definition

Description of the period of time over which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, which may be expressed in a variety of ways (for example, in years, month and year).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph 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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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Paragraph 2

-Subparagraph (a)(1)

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- Definition

The total fair value of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(2)

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Paragraph 2

-Subparagraph (d)(2)

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: 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

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Share-Based Compensation (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit recognized for share-based compensation arrangements	$ 3.2	$ 2.5	$ 3.9
Capitalized share-based compensation cost	0	0	0
Increase (decrease) in net excess tax benefits realized	0.9	0.1	(1.8)
Weighted-average period for which cost is expected to be recognized, in years	1.93
2008 Equity Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for future grants	2,965,033
Expiration date of shares available for future grant	May 25, 2020
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation options awarded, vesting period	over a three-year period
Stock options term in years	10
Total unrecognized compensation cost related to grants	2.4
Weighted-average period for which cost is expected to be recognized, in years	1.9
Service Award Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation options awarded, vesting period	vest in four equal annual installments
Total unrecognized compensation cost related to grants	2.0
Total fair value of share awards vested	2.6	2.3	2.0
Performance Award Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation options awarded, vesting period	vest in four equal annual installments
Total unrecognized compensation cost related to grants	2.0
Weighted-average period for which cost is expected to be recognized, in years	3.04
Total fair value of share awards vested	0.8
Maximum percentage to return on invested capital for annual performance period	12.00%
DSU Service Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation options awarded, vesting period	over a four-year period
Total unrecognized compensation cost related to grants	0.1
Weighted-average period for which cost is expected to be recognized, in years	0.03
Total fair value of share awards vested	0.7
DSU Performance Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation options awarded, vesting period	vest in four equal annual installments
Total unrecognized compensation cost related to grants	0.5
Weighted-average period for which cost is expected to be recognized, in years	1.02
Total fair value of share awards vested	0.2
Maximum percentage to return on invested capital for annual performance period	12.00%
Nonvested Deferred Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to grants	1.2
Weighted-average period for which cost is expected to be recognized, in years	2.07
Total fair value of share awards vested	$ 0.7	$ 0.2	$ 1.4
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of lesser of fair market value the applicable three-month offering period	85.00%
Maximum New Limit [Member] \| Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of company common stock available for issuance	333,603