REVENUE (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	100.00%	100.00%	100.00%	100.00%
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue	100.00%	100.00%	100.00%	100.00%
Government Customer [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	17.00%	14.00%	16.00%	13.00%
Heavy Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	15.00%	17.00%	16.00%	18.00%
Light Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	10.00%	11.00%	10.00%	11.00%
Transportation [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	5.00%	5.00%	5.00%	5.00%
Healthcare Customer [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	8.00%	5.00%	7.00%	5.00%
Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	6.00%	8.00%	7.00%	8.00%
Retail/Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	8.00%	7.00%	8.00%	7.00%
Contractors [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	7.00%	8.00%	7.00%	8.00%
Natural Resources [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	3.00%	4.00%	3.00%	4.00%
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	21.00%	21.00%	21.00%	21.00%
Other Segments [Member]
Disaggregation of Revenue [Line Items]
Percent of Total Company Revenue	24.00%	23.00%	24.00%	23.00%
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	100.00%	100.00%	100.00%	100.00%
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue	72.00%	72.00%	72.00%	72.00%
United States [Member] | Government Customer [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	24.00%	19.00%	21.00%	18.00%
United States [Member] | Heavy Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	15.00%	19.00%	17.00%	19.00%
United States [Member] | Light Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	13.00%	13.00%	13.00%	13.00%
United States [Member] | Transportation [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	5.00%	5.00%	5.00%	6.00%
United States [Member] | Healthcare Customer [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	11.00%	7.00%	10.00%	7.00%
United States [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	7.00%	10.00%	8.00%	10.00%
United States [Member] | Retail/Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	10.00%	8.00%	10.00%	8.00%
United States [Member] | Contractors [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	9.00%	10.00%	9.00%	10.00%
United States [Member] | Natural Resources [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	2.00%	3.00%	2.00%	3.00%
United States [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	4.00%	6.00%	5.00%	6.00%
Canada [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	100.00%	100.00%	100.00%	100.00%
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue	4.00%	5.00%	4.00%	5.00%
Canada [Member] | Government Customer [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	10.00%	6.00%	10.00%	6.00%
Canada [Member] | Heavy Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	16.00%	20.00%	17.00%	21.00%
Canada [Member] | Light Manufacturing [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	7.00%	6.00%	6.00%	6.00%
Canada [Member] | Transportation [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	10.00%	8.00%	10.00%	8.00%
Canada [Member] | Healthcare Customer [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	0.00%	0.00%	0.00%	0.00%
Canada [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	10.00%	9.00%	9.00%	9.00%
Canada [Member] | Retail/Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	3.00%	4.00%	4.00%	4.00%
Canada [Member] | Contractors [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	10.00%	11.00%	9.00%	10.00%
Canada [Member] | Natural Resources [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	29.00%	32.00%	29.00%	32.00%
Canada [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage	5.00%	4.00%	6.00%	4.00%