v3.8.0.1
Intangible assets - Future Amortization (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Amortization expense for fiscal years 2018 through 2022 and thereafter      
2018 $ 2,674    
2019 1,937    
2020 1,832    
2021 1,455    
2022 1,261    
Thereafter 1,104    
Total $ 10,263 $ 13,783 $ 16,055