Accrued and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Payables and Accruals [Abstract]

Schedule of Accrued Liabilities

Accrued and other current liabilities as of December 31 consisted of the following:

	2017		2016
	(Thousands of dollars)
Salaries & wages	$	6,240	$	5,949
Incentive compensation	8,991		1,576
Income taxes	930		587
Interest	8,108		8,057
Vacation payable	7,619		5,700
Group medical	1,344		1,892
Transportations tax	971		427
Operating lease	710		769
Workers compensation	959		865
Other	5,978		2,524
Total accrued liabilities	$	41,850	$	28,346