Income Taxes - Income tax (benefit) expense (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Current:      
Federal $ (958) $ 932 $ 0
State 113 (10) 7
Foreign 5,865 1,424 0
Total current income tax expense 5,020 2,346 7
Deferred:      
Federal (7,550) (34,589) 2,005
State (31) (2,506) 177
Foreign (439) (1,340) 0
Deferred Income Tax Expense (Benefit) (8,020) (38,435) 2,182
Income tax (benefit) expense $ (3,000) $ (36,089) $ 2,189