Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Additional Information (Details)

v3.6.0.2
Commitments and Contingencies - Additional Information (Details)
$ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Oct. 31, 2012
Dec. 31, 2014
Sep. 30, 2014
Mar. 31, 2015
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Jun. 30, 2014
GBP (£)
Loss Contingencies [Line Items]                
Operating leases, rent expense         $ 6,147 $ 6,070 $ 5,667  
EEX                
Loss Contingencies [Line Items]                
Commitments as a result of acquisitions (up to)         $ 5,551     £ 4,500,000
Unfavorable Regulatory Action                
Loss Contingencies [Line Items]                
Anti-dumping duty rate 249.96%              
Countervailing duty rate, prior to increase 3.61% 3.61% 3.61%          
Countervailing duty rate 15.24%     31.18%