Stock-Based Compensation Stock Option Awards Outstanding (Details) (USD $)	12 Months Ended
Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding	1,819,444
Outstanding Options, Weighted Average Remaining Contractual Term	1 year 10 months 23 days
Outstanding Options, Weighted Average Exercise Price	$ 20.28
Options Exercisable	1,788,774
Exercisable Options, Weighted Average Exercise Price	$ 20.34
Option Range 1 Of Exercise Prices [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 15.17
Exercise Price Range, Upper Range Limit	$ 17.63
Options Outstanding	436,600
Outstanding Options, Weighted Average Remaining Contractual Term	3 years 9 months 6 days
Outstanding Options, Weighted Average Exercise Price	$ 16.72
Options Exercisable	407,597
Exercisable Options, Weighted Average Exercise Price	$ 16.71
Option Range 2 Of Exercise Prices [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 17.64
Exercise Price Range, Upper Range Limit	$ 19.36
Options Outstanding	397,167
Outstanding Options, Weighted Average Remaining Contractual Term	1 year 3 months 16 days
Outstanding Options, Weighted Average Exercise Price	$ 18.43
Options Exercisable	395,500
Exercisable Options, Weighted Average Exercise Price	$ 18.43
Option Range 3 Of Exercise Prices [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 19.37
Exercise Price Range, Upper Range Limit	$ 21.78
Options Outstanding	240,000
Outstanding Options, Weighted Average Remaining Contractual Term	0 years 6 months 19 days
Outstanding Options, Weighted Average Exercise Price	$ 20.63
Options Exercisable	240,000
Exercisable Options, Weighted Average Exercise Price	$ 20.63
Option Range 4 Of Exercise Prices [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 21.79
Exercise Price Range, Upper Range Limit	$ 22.54
Options Outstanding	360,377
Outstanding Options, Weighted Average Remaining Contractual Term	1 year 9 months 24 days
Outstanding Options, Weighted Average Exercise Price	$ 21.91
Options Exercisable	360,377
Exercisable Options, Weighted Average Exercise Price	$ 21.91
Option Range 5 Of Exercise Prices [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Range, Lower Range Limit	$ 22.55
Exercise Price Range, Upper Range Limit	$ 25.00
Options Outstanding	385,300
Outstanding Options, Weighted Average Remaining Contractual Term	1 year 5 months 29 days
Outstanding Options, Weighted Average Exercise Price	$ 24.48
Options Exercisable	385,300
Exercisable Options, Weighted Average Exercise Price	$ 24.48

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

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)(iii)

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

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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 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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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 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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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

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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

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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- Definition

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

+ 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 (e)(1)

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

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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.

+ 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 (g)

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

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