Goodwill and Intangible Assets (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment losses in connection with the goodwill	$ 0	$ 0
Impairment losses in connection with the intangible assets	0	0
Amortization expense related to other intangible assets	$ 2,900,000	$ 2,700,000	$ 5,700,000	$ 5,600,000
Other intangible assets recorded in asset acquisitions			1,900,000
Goodwill, changes in foreign currency exchange rates			2,600,000
Other intangible assets, changes in foreign currency exchange rates			$ 600,000