Bank Credit Arrangements - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	May 24, 2019	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Feb. 19, 2020
Debt Instrument [Line Items]
Line of credit facility borrowing Capacity						$ 160,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Expiration of credit facility	May 2024
Revolving credit facility interest rate percentage		2.52%	2.63%	2.55%	3.45%