Revenue from Contracts with Clients (Details)	3 Months Ended		6 Months Ended
	Mar. 31, 2020 Rate	Mar. 31, 2019 Rate	Mar. 31, 2020 Rate	Mar. 31, 2019 Rate
Revenues from Contracts With Clients [Abstract]
Revenues from contracts with clients as a % of total revenues	0.70%	1.40%	0.80%	1.60%
Revenues from contracts with clients as a % of operating revenues	37.90%	38.40%	38.50%	41.60%