Income taxes (Details) - USD ($) |
3 Months Ended | 6 Months Ended | ||||
|---|---|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
Dec. 31, 2016 |
|
| Income Tax Disclosure [Abstract] | ||||||
| Deferred tax assets, valuation allowance | $ 12,000,000 | |||||
| Valuation allowance, change in amount | $ 0 | |||||
| Provision for income tax | $ 203,203 | $ 545,613 | $ 186,457 | $ 479,662 | ||
| Effective income tax rate | 14.90% | (60.80%) | 16.13% | (6.60%) | ||
| X | ||||||||||
- 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://www.xbrl.org/2003/role/presentationRef
|
| 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
|
| X | ||||||||||
- References No definition available.
|
| 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
|
| X | ||||||||||
- Definition Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|