Significant Accounting Policies - Summary of Property and Equipment Balances and Estimated Useful Lives (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 978,913	$ 919,378
Accumulated depreciation and amortization	(659,285)	(611,021)
Total property and equipment, net	319,628	308,357	$ 313,717
Land
Property Plant And Equipment [Line Items]
Total property and equipment, gross	10,061	11,130
Buildings and building improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	53,132	64,251
Leasehold improvements
Property Plant And Equipment [Line Items]
Total property and equipment, gross	281,195	274,848
Furniture, fixtures and equipment
Property Plant And Equipment [Line Items]
Total property and equipment, gross	$ 634,525	$ 569,149
Minimum | Buildings and building improvements
Property Plant And Equipment [Line Items]
Estimated useful lives	5 years
Minimum | Leasehold improvements
Property Plant And Equipment [Line Items]
Estimated useful lives	2 years
Minimum | Furniture, fixtures and equipment
Property Plant And Equipment [Line Items]
Estimated useful lives	2 years
Maximum | Buildings and building improvements
Property Plant And Equipment [Line Items]
Estimated useful lives	40 years
Maximum | Leasehold improvements
Property Plant And Equipment [Line Items]
Estimated useful lives	10 years
Maximum | Furniture, fixtures and equipment
Property Plant And Equipment [Line Items]
Estimated useful lives	10 years