Segment Information - Balance Sheet Information by Segment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 19,606,583	$ 17,240,239
Total assets	22,516,968	22,192,989
Operating Segments | Distribution
Segment Reporting Information [Line Items]
Property, plant and equipment, net	14,402,578	12,723,532
Total assets	21,716,467	21,424,586
Operating Segments | Pipeline and Storage
Segment Reporting Information [Line Items]
Property, plant and equipment, net	5,204,005	4,516,707
Total assets	5,504,972	4,797,206
Eliminations
Segment Reporting Information [Line Items]
Property, plant and equipment, net	0	0
Total assets	$ (4,704,471)	$ (4,028,803)