Details of Selected Consolidated Balance Sheet Captions - Goodwill Detail Table (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2019 USD ($)
Goodwill [Roll Forward]
Goodwill beginning balance	$ 730,419
Deferred tax adjustments on prior acquisitions	287
Goodwill ending balance	730,706
Goodwill, Period Increase (Decrease)	300
Distribution
Goodwill [Roll Forward]
Goodwill beginning balance	587,342
Deferred tax adjustments on prior acquisitions	262
Goodwill ending balance	587,604
Pipeline and Storage
Goodwill [Roll Forward]
Goodwill beginning balance	143,077
Deferred tax adjustments on prior acquisitions	25
Goodwill ending balance	$ 143,102