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Capital Structure - Narrative (Details) - USD ($) | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017 | Feb. 08, 2017
Class of Stock [Line Items] |  |  |
Additional paid-in capital | $ 959,500,000 | $ 954,700,000 |
Aggregate liquidation preferences | 525,000,000 | 525,000,000 |
Issuance costs | $ 13,100,000 | $ 13,100,000 |
Repurchase Program 2017 |  |  |
Class of Stock [Line Items] |  |  |
Existing share repurchase authorization amount |  |  | $ 250,000,000

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- Definition Aggregate liquidation preferences. + References No definition available. + Details
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- Definition Preferred stock issuance cost. + References No definition available. + Details
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- Definition Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(30)(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of stock repurchase plan authorized. + References No definition available. + Details
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- Details
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