v3.8.0.1
Commitments and Contingencies - Capital Leases (Details)
$ in Thousands
Dec. 31, 2017
USD ($)
Capital Leased Assets [Line Items]  
2018 $ 200
2019 200
2020 200
2021 33
2022 0
Thereafter 0
MASSACHUSETTS | Superior  
Capital Leased Assets [Line Items]  
Capital lease obligations 600
Development Authority of Columbus, GA | Maximum  
Capital Leased Assets [Line Items]  
Tax-exempt bond $ 18,000