Income Taxes - Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Taxes
Statutory federal tax rate (as a percent)	21.00%	21.00%	21.00%
Income (loss) before income taxes:
U.S.	$ 37,538	$ 38,864	$ (11,417)
Foreign	14,364	18,750	1,634
Income (loss) before income taxes	51,902	57,614	(9,783)
Current:
U.S. Federal	7,366	2,031	741
Foreign	2,741	3,302	349
State	490	639	228
Total	10,597	5,972	1,318
Deferred:
U.S. Federal	(1,509)	5,931	(2,986)
Foreign	459	120	470
State	25	(300)	(317)
Valuation allowance	355	804	415
Total	(670)	6,555	(2,418)
Total provision for (benefit from) income taxes	$ 9,927	$ 12,527	$ (1,100)