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Equity Incentive Plans and Stock-Based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017 | Apr. 23, 2015
Stock-Based Compensation |  |  |  |
Entity Closing Stock Price | $ 13.43 |  |  |
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense | $ 0.2 | $ 0.3 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate | 0.00% |  |  |
Minimum [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 0.00% |  |  |
Maximum [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 200.00% |  |  |
Stock Compensation Plan [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Shares available for issuance | 1,387,911 |  | 5,051,147 |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 35,400,000 |  |  | 4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures | 551,479 |  |  |
Employee Stock Option [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | 4,552,901 |  | 4,310,361 |
Share Based Compensation Arrangement by Share Based Payment Award Options, In The Money Outstanding, Number | 4,195,277 |  |  |
Share Based Compensation Arrangement By Share Based Payment Award, Options in the Money Exercisable, Number | 2,962,040 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures | 551,479 | 458,426 |  |
Share Based Compensation Arrangement by Share Based Payment Award Options, Grants in Period, Total Fair Value | $ 2.3 | $ 1.9 |  |
Stock-based compensation | 0.6 | 0.8 |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ 5.0 |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | 3 years 4 days |  |  |
Total fair value of options vested | $ 15.6 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | 1.0 | 2.0 |  |
Proceeds from Stock Options Exercised | $ 1.1 |  |  |
Employee Stock [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Shares available for issuance | 836,273 |  |  |
Share Based Compensation Arrangement by Share Based Payment Award Discount from Market Price Specific Date | 15.00% |  |  |
Stock-based compensation | $ 0.5 | $ 0.5 |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ 0.2 |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | 1 month |  |  |
Restricted Stock and Stock Units [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Granted (in shares) | 2,076,197 | 2,039,808 |  |
Stock-based compensation | $ 6.5 | $ 5.3 |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ 57.2 |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | 2 years 8 months 1 day |  |  |
Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Nonvested Requisite Service Period | 4 years |  |  |
Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Nonvested Grants in Period Total Fair Value | $ 26.8 | 26.2 |  |
Performance Shares [Member] | Restricted Stock and Stock Units [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Stock-based compensation | $ 1.3 | $ 0.9 |  |
Director [Member] | Restricted Stock and Stock Units [Member] |  |  |  |
Stock-Based Compensation |  |  |  |
Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Nonvested Requisite Service Period | 1 year |  |  |

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- Definition Represents the total fair value of vested stock options. + References No definition available. + Details
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- Definition Represents the total fair value of nonvested equity stock units granted during the period. + References No definition available. + Details
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- Definition Represents the total fair value of options for granted during the period. + References No definition available. + Details
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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 S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, 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 (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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 Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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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=96867065&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=96867065&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=96867065&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=96867065&loc=d3e5070-113901 + Details
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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) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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