Distributions of Available Cash - Additional Information (Details)	9 Months Ended
	Jun. 30, 2018 $ / shares
Distributions Made To Members Or Limited Partners [Abstract]
Distributions to its partners	45 days
Declaration date of quarterly distribution	Jul. 26, 2018
Distributions paid (in dollars per unit)	$ 0.60
Common Unit distribution on an annualized basis (in dollars per unit)	$ 2.40
Distribution date of quarterly distribution	Aug. 14, 2018
Date of record of quarterly distribution	Aug. 07, 2018