Business Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) country	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Gain on sale of equity investment	$ 13,700
Impairment of non-customer note receivable		$ 0	$ 0	$ 30,000
Other | World Courier
Segment Reporting Information [Line Items]
Number of countries in which entity operates (over) | country		50
Other Nonoperating Income (Expense)
Segment Reporting Information [Line Items]
Gain on sale of equity investment			$ 13,700
Impairment of non-customer note receivable				$ 30,000