Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts payable and other accrued liabilities:
Accounts payable	$ 20,571	$ 18,793
Accrued liabilities	11,580	13,749
Total Accounts payable and other accrued liabilities	32,151	32,542
Accrued payroll costs:
Payroll and benefits	34,525	34,768
Health insurance liabilities	3,873	2,680
Payroll taxes	898	920
Workers’ compensation liabilities	1,015	1,016
Total Accrued payroll costs	$ 40,311	$ 39,384