Leases - Additional balance sheet information (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021
ASSETS
Operating lease assets	$ 584,993	$ 607,076
Balance Sheet classification of operating lease assets	Operating lease assets	Operating lease assets
Finance lease assets	$ 48,000	$ 44,400
Balance Sheet classification of finance lease assets	PROPERTY AND EQUIPMENT-NET	PROPERTY AND EQUIPMENT-NET
Total lease assets	$ 633,000	$ 651,500
Current:
Operating lease liabilities	$ 154,200	$ 157,300
Balance Sheet classification of operating lease liabilities	Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Finance lease liabilities	$ 16,200	$ 13,400
Balance Sheet classification of finance lease liabilities	Current portion of long-term debt	Current portion of long-term debt
Total current lease liabilities	$ 170,400	$ 170,700
Operating lease liabilities	$ 653,785	$ 679,059
Balance Sheet classification of operating lease liabilities	Operating lease liabilities	Operating lease liabilities
Finance lease liabilities	$ 33,700	$ 32,100
Balance Sheet classification of finance lease liabilities	LONG-TERM DEBT	LONG-TERM DEBT
Total non-current lease liabilities	$ 687,500	$ 711,200
Weighted average remaining lease term (in years):
Operating leases	6 years 9 months 18 days	6 years 10 months 24 days
Finance leases	3 years 4 months 24 days	3 years 6 months
Weighted average discount rates:
Operating leases	4.20%	4.30%
Finance leases	4.10%	4.30%