Leases - Operating Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Leases [Abstract]
Operating lease expense	$ 13,431	$ 37,724
Short-term lease expense	878	2,505
Variable lease expense	6,062	16,163
Total lease expense	$ 20,371	$ 56,392