Leases - Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Oct. 01, 2019
Cash paid for amounts included in the measurement of lease liabilities
Operating lease cash payments	$ 115,028
Right-of-use assets obtained in exchange for lease liabilities
New operating leases	$ 61,779
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member	us-gaap:AccountingStandardsUpdate201409Member
Leases recognized upon adoption of ASC 842	$ 443,522		$ 3,200	$ 526,281