REVENUE (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) region	Sep. 30, 2018 USD ($) region	Sep. 30, 2019 USD ($) region	Sep. 30, 2018 USD ($) region
REVENUE
Revenue	$ 328,968	$ 396,970	$ 1,015,501	$ 1,166,612
Permian Basin
REVENUE
Revenue	158,609	166,330	469,391	449,113
MidCon
REVENUE
Revenue	45,522	58,275	152,500	187,300
Eagle Ford
REVENUE
Revenue	44,694	46,895	124,453	135,923
Bakken
REVENUE
Revenue	20,052	41,673	66,195	120,934
Marcellus/Utica
REVENUE
Revenue	21,330	37,110	79,781	106,129
Rockies
REVENUE
Revenue	21,045	23,228	64,981	85,908
Haynesville/E. Texas
REVENUE
Revenue	18,322	13,319	53,918	43,328
All other
REVENUE
Revenue	$ (606)	$ 10,140	$ 4,282	$ 37,977
Permian Basin, MidCon and Eagle Ford | Water services
REVENUE
Number of revenue producing regions | region	3	3	3	3
Percentage of revenue	75.00%	73.00%	75.00%	71.00%
Permian Basin and Bakken | Water infrastructure
REVENUE
Number of revenue producing regions | region	2	2	2	2
Percentage of revenue	84.00%	85.00%	83.00%	84.00%
Permian Basin and MidCon | Oilfield chemicals
REVENUE
Number of revenue producing regions | region	2	2	2	2
Percentage of revenue	79.00%	81.00%	77.00%	76.00%