Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Compensation	$ 19,844	$ 13,732
Non-income taxes	6,520	7,383
Royalty tax withholdings	7,587	6,921
Other expenses	18,038	13,070
Total accrued expenses	$ 51,989	$ 41,106