Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021
Assets:
Cash and cash equivalents	$ 77,905	$ 114,314
Short-term investments	23,622	19,667
Other assets	9,452	9,100
Liabilities:
Deferred compensation	9,675	8,527
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	77,905	114,314
Short-term investments	23,622	19,667
Other assets	0	0
Liabilities:
Deferred compensation	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Other assets	9,452	9,100
Liabilities:
Deferred compensation	9,675	8,527
Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Other assets	0	0
Liabilities:
Deferred compensation	$ 0	$ 0