Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017
Property, Plant and Equipment
Gross property, plant and equipment	$ 2,170,475		$ 2,165,867
Accumulated depreciation	(400,857)		(375,594)
Net property, plant and equipment	1,769,618		1,790,273
Depreciation expense	32,344	$ 27,654
Capitalized interest expense	0	$ 3,735
Gain on sales and write-downs of certain assets	2,500
Natural gas liquids terminal and storage assets
Property, Plant and Equipment
Gross property, plant and equipment	$ 236,363		207,825
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	$ 253,022		248,582
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
Refined products terminal assets and equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 6,736		6,736
Refined products terminal assets and equipment | Minimum
Property, Plant and Equipment
Useful life	15 years
Refined products terminal assets and equipment | Maximum
Property, Plant and Equipment
Useful life	25 years
Retail propane equipment
Property, Plant and Equipment
Gross property, plant and equipment	$ 240,861		239,417
Retail propane equipment | Minimum
Property, Plant and Equipment
Useful life	2 years
Retail propane equipment | Maximum
Property, Plant and Equipment
Useful life	30 years
Vehicles and railcars
Property, Plant and Equipment
Gross property, plant and equipment	$ 196,576		198,480
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	$ 566,306		557,100
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	$ 220,732		203,003
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	$ 91,263		91,037
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	$ 44,009		43,880
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	$ 170,651		161,957
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	$ 59,261		56,545
Tank bottoms and line fill
Property, Plant and Equipment
Gross property, plant and equipment	24,462		24,462
Other
Property, Plant and Equipment
Gross property, plant and equipment	$ 23,630		39,132
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	$ 36,603		$ 87,711
Crude oil logistics
Property, Plant and Equipment
Gain on sales and write-downs of certain assets	$ 3,400