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Stock-Based Compensation (Stock Options) (Details) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | Jan. 31, 2017 | Mar. 01, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] |  |  |  |  |  |
Expected dividend rate (percentage) |  | 0.00% | 0.00% | 0.00% |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |  |  |  |  |  |
Exercised, shares |  | (300,000) | (1,300,000) | (1,700,000) |  |
Exercised, weighted-average exercise price (in dollars per share) |  | $ 31.21 | $ 23.33 | $ 20.50 |  |
Stock Options [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Exercise price of options to purchase common stock granted |  |  |  |  |  | $ 52.53
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |  |  |  |  |  |
Options outstanding, beginning balance (in shares) |  | 4,600,000 |  |  |  |
Options outstanding, weighted-average exercise price, beginning balance (in dollars per share) |  | $ 45.07 |  |  |  |
Granted, shares | [1] | 900,000 |  |  |  |
Granted, weighted-average exercise price (in dollars per share) | [1] | $ 52.53 |  |  |  |
Exercised, shares |  | (300,000) |  |  |  |
Exercised, weighted-average exercise price (in dollars per share) |  | $ 31.21 |  |  |  |
Forfeited, shares |  | 0 |  |  |  |
Forfeited, weighted-average exercise price (in dollars per share) |  | $ 0.00 |  |  |  |
Expired, shares |  | 0 |  |  |  |
Expired, weighted-average exercise price (in dollars per share) |  | $ 0.00 |  |  |  |
Options outstanding, beginning balance (in shares) |  | 5,200,000 | 4,600,000 |  |  |
Options outstanding, weighted-average exercise price, ending balance (in dollars per share) |  | $ 46.99 | $ 45.07 |  |  |
Options outstanding, weighted-average remaining contractual term (years) |  | 6 years 6 months 15 days |  |  |  |
Options outstanding, aggregate intrinsic value |  | $ 31.8 |  |  |  |
Options exercisable (in shares) |  | 2,900,000 |  |  |  |
Options exercisable, weighted-average exercise price (in dollars per share) |  | $ 40.33 |  |  |  |
Options exercisable, weighted-average remaining contractual term (years) |  | 5 years 3 months 7 days |  |  |  |
Options exercisable, aggregate intrinsic value |  | $ 31.4 |  |  |  |
Options exercisable and expected to vest thereafter (in shares) |  | 5,200,000 |  |  |  |
Options exercisable and expected to vest thereafter, weighted-average exercise price (in dollars per share) |  | $ 46.92 |  |  |  |
Options exercisable and expected to vest thereafter, weighted-average remaining contractual term (years) |  | 6 years 6 months 11 days |  |  |  |
Options exercisable and expected to vest thereafter, aggregate intrinsic value |  | $ 31.8 |  |  |  |
Options available for future grants (in shares) | [2] | 3,300,000 |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] |  |  |  |  |  |
Weighted average grant-date fair value of stock options granted (in dollars per share) |  | $ 17.96 | $ 19.38 | $ 20.56 |  |
Total intrinsic value of stock options exercised |  | $ 5.3 | $ 51.9 | $ 56.2 |  |
Restricted Stock [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Granted, shares | [3] | 143,424 |  |  |  |
Minimum [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] |  |  |  |  |  |
Risk-free interest rate (percentage) |  | 1.16% | 0.76% | 1.11% |  |
Expected term (in years) |  | 4 years | 2 years | 4 years |  |
Expected volatility rate (percentage) |  | 29.00% | 24.00% | 25.00% |  |
Maximum [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract] |  |  |  |  |  |
Risk-free interest rate (percentage) |  | 1.55% | 1.86% | 2.04% |  |
Expected term (in years) |  | 7 years | 7 years | 7 years |  |
Expected volatility rate (percentage) |  | 31.00% | 34.00% | 36.00% |  |
Employee [Member] | 2008 Equity and Incentive Plan |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Number of shares authorized |  | 12,000,000 |  |  |  |
Employee [Member] | 2008 Equity and Incentive Plan | Stock Options [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |  |  |  |  |  |
Options available for future grants (in shares) |  | 2,500,000 |  |  |  |
Director [Member] | Non-Employee Director Equity Plan 2014 [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Number of shares authorized |  | 1,000,000 |  |  |  |
Director [Member] | Non-Employee Director Equity Plan 2014 [Member] | Stock Options [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |  |  |  |  |  |
Options available for future grants (in shares) |  | 900,000 |  |  |  |
Subsequent Event [Member] | Employee [Member] | 2008 Equity and Incentive Plan | Stock Options [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] |  |  |  |  |  |
Options available for future grants (in shares) |  |  |  |  | 0 |
Subsequent Event [Member] | Employee [Member] | Equity and Incentive Plan, 2017 [Member] | Stock Options [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Number of shares authorized |  |  |  |  | 5,500,000 |
Subsequent Event [Member] | Director [Member] | Non-Employee Director Equity Plan 2014 [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Number of shares authorized |  |  |  |  | 600,000 |
Subsequent Event [Member] | Director [Member] | Non-Employee Director Equity Plan 2014 [Member] | Stock Options [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] |  |  |  |  |  |
Reduction in Shares Available Issuance |  |  |  |  | 400,000 |
AwardsGranted2016 [Member] | Equity Option [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Expiration period (in years) |  | 10 years |  |  |  |
Vesting period (in years) |  | 4 years |  |  |  |
AwardsGranted2016 [Member] | Restricted Stock [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Vesting period (in years) |  | 4 years |  |  |  |
Awards Granted 2015 and 2014 [Member] | Equity Option [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Expiration period (in years) |  | 10 years |  |  |  |
Vesting period (in years) |  | 4 years |  |  |  |
Awards Granted 2015 and 2014 [Member] | Restricted Stock [Member] |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |
Vesting period (in years) |  | 4 years |  |  |  |
[1] | The options granted during 2016 are related to our annual employee stock option award grant on March 1, 2016
[2] | Includes 2.5 million shares available under the 2008 Plan and 0.9 million shares available under the 2014 Director Plan. As noted above, the number of shares available under the 2014 Director Plan was reduced by 0.4 million shares in January 2017. If our stockholders approve the 2017 Plan, under which 5.5 million shares would be available for issuance, then no additional awards will be granted under the 2008 Plan, and the 2.5 million shares available under the 2008 Plan will no longer be available for issuance.
[3] | The restricted stock awards granted during 2016 are primarily related to our employee annual restricted stock award grant in March 2016.

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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target 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)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. + 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 (f)(2)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over 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 (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + 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 (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + 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 (a)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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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 + Details
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- Definition 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 + Details
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- Definition 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. + 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 + Details
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- Definition Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements. + 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)(4) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition 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. + 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) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + 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 (d)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding. + 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 + Details
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- Definition 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 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)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average price at which grantees can acquire the shares reserved for issuance under the stock 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)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest. + 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)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired. + References No definition available. + Details
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