Stock-Based Compensation (Summary of Options Outstanding and Options Exerciseable) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock options, Outstanding at January 1, Number of options	3,649,520	4,741,732	4,769,122
Stock options, Granted, Number of options	571,166	613,120	853,478
Stock options, Exercised, Number of options	(833,132)	(1,607,784)	(850,659)
Stock options, Forfeited or expired, Number of options	(74,861)	(97,548)	(30,209)
Stock options, Outstanding at December 31, Number of options	3,312,693	3,649,520	4,741,732
Stock options, Outstanding at January 1, Weighted average exercise price	$ 29.84	$ 21.24	$ 16.13
Stock options, Granted, Weighted average exercise price	$ 38.95	$ 34.34	$ 36.64
Stock options, Exercised, Weighted average exercise price	$ 12.12	$ 5.71	$ 7.54
Stock options, Forfeited or expired, Weighted average exercise price	$ 37.31	$ 37.76	$ 35.46
Stock options, Outstanding at December 31, Weighted average exercise price	$ 35.70	$ 29.84	$ 21.24
Stock Options [Member]
Stock options, Outstanding at December 31, Number of options	3,312,693
Stock options, Outstanding at December 31, Weighted average exercise price	$ 35.70
Options Outstanding - Weighted Average Remaining Contractual Life (Years)	4 years 4 months 24 days
Options Outstanding - Aggregate Intrinsic Value (thousands)	$ 12,882
Stock options, Exercisable at December 31,	2,103,828
Stock options Exercisable at December 31, Weighted average exercise price	$ 34.96
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 10 months 24 days
Options Exercisable - Weighted Average Remaining Contractual Life (Years)	2 years 10 months 24 days
Options Exercisable - Aggregate Intrinsic Value (thousands)	$ 10,022
Range of Exercise Prices $20.34-$29.69 [Member] \| Stock Options [Member]
Stock options, Outstanding at December 31, Number of options	273,134
Stock options, Outstanding at December 31, Weighted average exercise price	$ 27.31
Options Outstanding - Weighted Average Remaining Contractual Life (Years)	1 year 2 months 12 days
Stock options, Exercisable at December 31,	265,025
Stock options Exercisable at December 31, Weighted average exercise price	$ 27.29
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	1 year 1 month 6 days
Options Exercisable - Weighted Average Remaining Contractual Life (Years)	1 year 1 month 6 days
Range of Exercise Prices $30.23-$35.91 [Member] \| Stock Options [Member]
Stock options, Outstanding at December 31, Number of options	1,087,218
Stock options, Outstanding at December 31, Weighted average exercise price	$ 33.09
Options Outstanding - Weighted Average Remaining Contractual Life (Years)	4 years 3 months 18 days
Stock options, Exercisable at December 31,	677,387
Stock options Exercisable at December 31, Weighted average exercise price	$ 32.32
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	3 years 4 months 24 days
Options Exercisable - Weighted Average Remaining Contractual Life (Years)	3 years 4 months 24 days
Range of Exercise Prices $36.22-$39.91 [Member] \| Stock Options [Member]
Stock options, Outstanding at December 31, Number of options	1,587,066
Stock options, Outstanding at December 31, Weighted average exercise price	$ 37.56
Options Outstanding - Weighted Average Remaining Contractual Life (Years)	5 years 4 months 24 days
Stock options, Exercisable at December 31,	803,412
Stock options Exercisable at December 31, Weighted average exercise price	$ 36.74
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 4 months 24 days
Options Exercisable - Weighted Average Remaining Contractual Life (Years)	4 years 4 months 24 days
Range of Exercise Prices $40.15-$51.47 [Member] \| Stock Options [Member]
Stock options, Outstanding at December 31, Number of options	365,275
Stock options, Outstanding at December 31, Weighted average exercise price	$ 41.64
Options Outstanding - Weighted Average Remaining Contractual Life (Years)	3 years
Stock options, Exercisable at December 31,	358,004
Stock options Exercisable at December 31, Weighted average exercise price	$ 41.62
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 10 months 24 days
Options Exercisable - Weighted Average Remaining Contractual Life (Years)	2 years 10 months 24 days

Number of stock options exercised in the current period.

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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the 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)(iii)

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

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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- Definition

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

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ 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)(iv)(3)-(4)

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- Definition

Weighted average price of options that were either forfeited or expired.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)-(4)

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

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- Definition

Net number of share options (or share units) granted during the period.

+ 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)(iv)(1)

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

+ 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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-Publisher FASB

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-Topic 718

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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

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

-Publisher FASB

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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