Income taxes (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Income taxes | ||
| Income tax expense | $ 128 | $ 199 |
| Effective tax rate (as a percent) | 4.80% | 3.00% |
| X | ||||||||||
- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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