Business Combinations - Business Acquisition, Pro Forma Adjustments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Adjustments to net revenues
Exalenz pre-acquisition net revenues	$ 0	$ 286	$ 0	$ 7,464
Adjustments to net earnings
Exalenz pre-acquisition net loss	0	(4,919)	0	(6,423)
Pro forma adjustments:
Meridian acquisition-related costs	0	1,641	0	3,428
Exalenz transaction-related costs	0	4,104	0	4,550
Gain on Exalenz purchase price currency contracts	0	(845)	0	(845)
Remove net impact of non-continuing personnel, locations or activities	0	(446)	0	(301)
Incremental depreciation and amortization	0	(240)	0	(2,064)
Interest, net	0	444	0	(328)
Tax effects of pro forma adjustments and recognizing benefit on resulting Exalenz losses	0	157	0	723
Total adjustments to net earnings	$ 0	$ (104)	$ 0	$ (1,260)