Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Mar. 31, 2025
Property, Plant and Equipment
Gross property, plant and equipment	$ 3,219,462		$ 3,219,462		$ 3,171,429
Accumulated depreciation	(1,185,359)		(1,185,359)		(1,104,582)
Net property, plant and equipment	2,034,103		2,034,103		2,066,847
Depreciation expense	50,699	$ 48,021	104,116	$ 95,940
Capitalized interest expense	146	$ 963	230	$ 1,506
Gain (loss) on sales and write-downs of certain assets	6,366		7,843
Corporate and other
Property, Plant and Equipment
Gain (loss) on sales and write-downs of certain assets	(1)		(2)
Water Solutions
Property, Plant and Equipment
Gain (loss) on sales and write-downs of certain assets	6,377		7,871
Crude Oil Logistics
Property, Plant and Equipment
Gain (loss) on sales and write-downs of certain assets	(10)		(13)
Liquids Logistics
Property, Plant and Equipment
Gain (loss) on sales and write-downs of certain assets	0		(13)
Water treatment facilities and equipment (1)
Property, Plant and Equipment
Gross property, plant and equipment	2,266,185		2,266,185		2,240,919
Finance lease, right-of-use asset	$ 5,800		$ 5,800
Water treatment facilities and equipment (1) | Minimum
Property, Plant and Equipment
Useful life	3 years		3 years
Water treatment facilities and equipment (1) | Maximum
Property, Plant and Equipment
Useful life	30 years		30 years
Pipeline and related facilities
Property, Plant and Equipment
Gross property, plant and equipment	$ 266,324		$ 266,324		266,324
Pipeline and related facilities | Minimum
Property, Plant and Equipment
Useful life	30 years		30 years
Pipeline and related facilities | Maximum
Property, Plant and Equipment
Useful life	40 years		40 years
Crude oil tanks and related equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 230,784		$ 230,784		230,174
Crude oil tanks and related equipment | Minimum
Property, Plant and Equipment
Useful life	2 years		2 years
Crude oil tanks and related equipment | Maximum
Property, Plant and Equipment
Useful life	30 years		30 years
Buildings and leasehold improvements
Property, Plant and Equipment
Gross property, plant and equipment	$ 124,562		$ 124,562		124,388
Buildings and leasehold improvements | Minimum
Property, Plant and Equipment
Useful life	3 years		3 years
Buildings and leasehold improvements | Maximum
Property, Plant and Equipment
Useful life	40 years		40 years
Natural gas liquids terminal and storage assets
Property, Plant and Equipment
Gross property, plant and equipment	$ 100,137		$ 100,137		99,805
Natural gas liquids terminal and storage assets | Minimum
Property, Plant and Equipment
Useful life	2 years		2 years
Natural gas liquids terminal and storage assets | Maximum
Property, Plant and Equipment
Useful life	30 years		30 years
Land
Property, Plant and Equipment
Gross property, plant and equipment	$ 64,603		$ 64,603		64,733
Tank bottoms and linefill (2)
Property, Plant and Equipment
Gross property, plant and equipment	31,555		31,555		30,623
Information technology equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 30,970		$ 30,970		31,319
Information technology equipment | Minimum
Property, Plant and Equipment
Useful life	3 years		3 years
Information technology equipment | Maximum
Property, Plant and Equipment
Useful life	7 years		7 years
Vehicles and railcars (3)
Property, Plant and Equipment
Gross property, plant and equipment	$ 22,763		$ 22,763		33,629
Finance lease, right-of-use asset	$ 100		$ 100		100
Vehicles and railcars (3) | Minimum
Property, Plant and Equipment
Useful life	3 years		3 years
Vehicles and railcars (3) | Maximum
Property, Plant and Equipment
Useful life	25 years		25 years
Other
Property, Plant and Equipment
Gross property, plant and equipment	$ 19,269		$ 19,269		19,161
Other | Minimum
Property, Plant and Equipment
Useful life	3 years		3 years
Other | Maximum
Property, Plant and Equipment
Useful life	20 years		20 years
Construction in progress
Property, Plant and Equipment
Gross property, plant and equipment	$ 62,310		$ 62,310		$ 30,354