Leases - Summary of Other Lease Information (Details) $ in Thousands	9 Months Ended
	Jun. 30, 2020 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows – operating leases	$ 147,959
Operating cash flows – finance leases	33
Financing cash flows – finance leases	3
Supplemental non-cash information on lease liabilities:
Lease assets obtained in exchange for new operating lease liabilities	151,528
Lease assets obtained in exchange for new finance lease liabilities	$ 4
Weighted-average remaining lease term (in years):
Operating leases	4 years 10 months 24 days
Finance leases	4 years
Weighted-average discount rate:
Operating leases	4.30%
Finance leases	5.00%