Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment
Gross property, plant and equipment	$ 3,380,623	$ 2,246,397
Accumulated depreciation	(529,068)	(417,457)
Net property, plant and equipment	2,851,555	1,828,940
Depreciation expense	132,791	101,515	$ 99,954
Capitalized interest expense	650	482	182
(Gain) loss on sales and write-downs of certain assets	22,497	7,549	5,620
Crude oil logistics
Property, Plant and Equipment
(Gain) loss on sales and write-downs of certain assets	36	3,489	(3,144)
Water solutions
Property, Plant and Equipment
(Gain) loss on sales and write-downs of certain assets	22,491	3,067	8,117
Liquids and refined products
Property, Plant and Equipment
(Gain) loss on sales and write-downs of certain assets	(30)	993	639
Corporate and Other
Property, Plant and Equipment
(Gain) loss on sales and write-downs of certain assets	0	0	$ 8
Natural gas liquids terminal and storage assets
Property, Plant and Equipment
Gross property, plant and equipment	$ 314,694	280,106
Natural gas liquids terminal and storage assets | Minimum
Property, Plant and Equipment
Useful life	2 years
Natural gas liquids terminal and storage assets | Maximum
Property, Plant and Equipment
Useful life	30 years
Pipeline and related facilities
Property, Plant and Equipment
Gross property, plant and equipment	$ 244,751	243,799
Pipeline and related facilities | Minimum
Property, Plant and Equipment
Useful life	30 years
Pipeline and related facilities | Maximum
Property, Plant and Equipment
Useful life	40 years
Vehicles and railcars
Property, Plant and Equipment
Gross property, plant and equipment	$ 123,937	124,948
Vehicles and railcars | Minimum
Property, Plant and Equipment
Useful life	3 years
Vehicles and railcars | Maximum
Property, Plant and Equipment
Useful life	25 years
Water treatment facilities and equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 1,525,859	704,666
Water treatment facilities and equipment | Minimum
Property, Plant and Equipment
Useful life	3 years
Water treatment facilities and equipment | Maximum
Property, Plant and Equipment
Useful life	30 years
Crude oil tanks and related equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 234,143	225,476
Crude oil tanks and related equipment | Minimum
Property, Plant and Equipment
Useful life	2 years
Crude oil tanks and related equipment | Maximum
Property, Plant and Equipment
Useful life	30 years
Barges and towboats
Property, Plant and Equipment
Gross property, plant and equipment	$ 125,162	103,735
Barges and towboats | Minimum
Property, Plant and Equipment
Useful life	5 years
Barges and towboats | Maximum
Property, Plant and Equipment
Useful life	30 years
Information technology equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 34,261	31,831
Information technology equipment | Minimum
Property, Plant and Equipment
Useful life	3 years
Information technology equipment | Maximum
Property, Plant and Equipment
Useful life	7 years
Buildings and leasehold improvements
Property, Plant and Equipment
Gross property, plant and equipment	$ 151,690	143,711
Buildings and leasehold improvements | Minimum
Property, Plant and Equipment
Useful life	3 years
Buildings and leasehold improvements | Maximum
Property, Plant and Equipment
Useful life	40 years
Land
Property, Plant and Equipment
Gross property, plant and equipment	$ 91,446	62,379
Tank bottoms and line fill
Property, Plant and Equipment
Gross property, plant and equipment	20,346	20,071
Other
Property, Plant and Equipment
Gross property, plant and equipment	$ 14,627	14,870
Other | Minimum
Property, Plant and Equipment
Useful life	3 years
Other | Maximum
Property, Plant and Equipment
Useful life	20 years
Construction in progress
Property, Plant and Equipment
Gross property, plant and equipment	$ 499,707	$ 290,805