Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accrued Liabilities, Current [Abstract]
Accrued salaries, wages and benefits	$ 6,898	$ 9,632
Accrual for insurance liabilities	5,492	5,233
Property taxes	1,747	513
Capital lease liability	1,310	0
Sales taxes	1,881	1,836
Interest	34	46
Other accrued expenses	337	613
Total accrued liabilities	$ 17,699	$ 17,873