Compensation Plans (Details) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 6,024,000	$ 6,344,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Represented by Each RSU	1
Unrecognized stock based compensation expense	19,300,000
Stock-based compensation expense	2,900,000	2,800,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Awards Other Than Options, Performance Measurement Period	3
Unrecognized stock based compensation expense	18,100,000
Stock-based compensation expense	$ 2,300,000	$ 3,200,000
Performance Shares [Member] \| Minimum PSU Multiplier [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Low End of Range	0.00%
Performance Shares [Member] \| Maximum PSU Multiplier [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Low End of Range	200.00%

Number of Shares Represented by Each RSU

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- Definition

Period over which company performance is measured in order to compute the multiplier to apply to PSU awards

+ References

No definition available.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, 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 Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

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-Topic 718

-SubTopic 10

-Section S99

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-Subparagraph (SAB TOPIC 14.F)

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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- Definition

Percentage of vesting of share-based compensation awards.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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