Leases - Supplemental Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 300,680	$ 0
Operating lease liabilities, current	46,010	0
Operating lease liabilities, long-term	338,715	$ 0
Total lease liabilities	$ 384,725
Weighted average remaining lease term (in years)	10 years 2 months 12 days
Weighted average discount rate	2.58%