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Earnings (loss) per share (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2017 | Mar. 31, 2016
Earnings Per Share [Abstract] |  |
Net loss | $ (15,139) | $ (16,163)
Amount allocated to common stockholders (in hundredths) | 100.00% | 100.00%
Basic EPS: |  |
Net loss allocated to common stockholders | $ (15,139) | $ (16,163)
Net loss allocated to common stockholders (shares) | 87,254,000 | 87,040,000
Net loss allocated to common stockholders (in dollars per share) | $ (0.17) | $ (0.19)
Stock options [Member] |  |
Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Securities excluded from calculation of diluted EPS (shares) | 207,716 | 393,237
Service-based share awards [Member] |  |
Securities Excluded from Computation of Earnings Per Share [Line Items] |  |
Securities excluded from calculation of diluted EPS (shares) | 1,037,320 | 498,809

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- Definition The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. + References No definition available. + Details
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