REVENUE (Details) $ in Thousands	3 Months Ended				9 Months Ended
	Mar. 31, 2020 USD ($) segment	Sep. 30, 2019 region	Mar. 31, 2019 USD ($)	Sep. 30, 2018 region	Sep. 30, 2019 region	Sep. 30, 2018 region
REVENUE
Number of Reportable Segments | segment	3
Revenue	$ 278,285		$ 362,646
Permian Basin
REVENUE
Revenue	137,998		162,665
MidCon
REVENUE
Revenue	24,873		58,463
Eagle Ford
REVENUE
Revenue	35,664		38,726
Bakken
REVENUE
Revenue	22,560		25,782
Marcellus/Utica
REVENUE
Revenue	19,839		30,159
Rockies
REVENUE
Revenue	18,869		22,442
Haynesville/E. Texas
REVENUE
Revenue	19,015		17,282
All other
REVENUE
Revenue	$ (533)		$ 7,127
Permian Basin, MidCon and Eagle Ford | Water services
REVENUE
Number of revenue producing regions | region		3		3	3	3
Percentage of revenue	74.00%		71.00%
Permian Basin and Bakken | Water infrastructure
REVENUE
Number of revenue producing regions | region		2		2	2	2
Percentage of revenue	87.00%		82.00%
Permian Basin and MidCon | Oilfield chemicals
REVENUE
Number of revenue producing regions | region		2		2	2	2
Percentage of revenue	70.00%		76.00%