Income taxes (Summary of valuation allowance) (Details) - USD ($) $ in Thousands |
12 Months Ended | |
|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Deferred Tax Assets, Valuation Allowance [Roll Forward] | ||
| Valuation allowance at beginning of period | $ 92,298 | $ 104,858 |
| Decrease of allowance to income tax provision | (17,937) | (12,560) |
| Valuation allowance at end of period | $ 74,361 | $ 92,298 |
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- Definition Deferred Tax Assets, Valuation Allowance No definition available.
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- Definition Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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