Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares |
Jun. 30, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Statement Of Financial Position [Abstract] | ||
| Preferred stock, par value | $ 0.01 | $ 0.01 |
| Preferred stock, shares authorized | 10,000,000 | 10,000,000 |
| Preferred stock, shares outstanding | 0 | 0 |
| Common stock, par value | $ 0.01 | $ 0.01 |
| Common stock, shares authorized | 180,000,000 | 180,000,000 |
| Common stock, issued | 94,470,636 | 94,533,246 |
| Common stock, outstanding | 94,470,636 | 94,533,246 |
| X | ||||||||||
- Definition Face amount or stated value per share of common stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- References No definition available.
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