Leases - Additional Information (Detail)	9 Months Ended
	Jun. 30, 2020
Lessee Lease Description [Line Items]
Weighted-average remaining lease term - operating leases	7 years 3 months 18 days
Weighted-average discount rate - operating leases	4.90%
Minimum
Lessee Lease Description [Line Items]
Operating lease expiration year	2020
Operating lease, term of contract	1 year
Maximum
Lessee Lease Description [Line Items]
Operating lease expiration year	2039
Operating lease, term of contract	20 years
Operating lease, option to extend, term	5 years