Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Sep. 30, 2020		35,513	6,353
Beginning balance at Sep. 30, 2020	$ 371,500	$ 355	$ (55,109)	$ 279,741	$ 170,330	$ (23,817)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,778				5,778
Other comprehensive (loss) income	2,068					2,068
Issuance of common stock, net of offering expenses	73,830	$ 40		73,790
Issuance of common stock, net of offering expenses (in shares)		4,025
Other	8				8
Employee stock purchase plan issuances (in shares)			(61)
Employee stock purchase plan issuances	916		$ 540	376
Taxes paid for net share settlement of share-based payment awards (in shares)			109
Taxes paid for net share settlement of share-based payment awards	(1,985)		$ (1,985)
Issuance of stock under stock award plans (in shares)		974
Issuance of stock under stock award plans	7,025	$ 10		7,015
Stock-based compensation expense	6,331			6,331
Ending balance (in shares) at Jun. 30, 2021		40,512	6,401
Ending balance at Jun. 30, 2021	465,471	$ 405	$ (56,554)	367,253	176,116	(21,749)
Beginning balance (in shares) at Mar. 31, 2021		40,442	6,413
Beginning balance at Mar. 31, 2021	459,152	$ 404	$ (56,595)	364,604	172,951	(22,212)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,157				3,157
Other comprehensive (loss) income	463					463
Other	8				8
Employee stock purchase plan issuances (in shares)			(18)
Employee stock purchase plan issuances	297		$ 160	137
Taxes paid for net share settlement of share-based payment awards (in shares)			6
Taxes paid for net share settlement of share-based payment awards	(119)		$ (119)
Issuance of stock under stock award plans (in shares)		70
Issuance of stock under stock award plans	403	$ 1		402
Stock-based compensation expense	2,110			2,110
Ending balance (in shares) at Jun. 30, 2021		40,512	6,401
Ending balance at Jun. 30, 2021	465,471	$ 405	$ (56,554)	367,253	176,116	(21,749)
Beginning balance (in shares) at Sep. 30, 2021		40,653	6,391
Beginning balance at Sep. 30, 2021	472,517	$ 407	$ (56,535)	370,699	180,692	(22,746)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,160				8,160
Other comprehensive (loss) income	(1,519)					(1,519)
Employee stock purchase plan issuances (in shares)			(60)
Employee stock purchase plan issuances	1,101		$ 547	554
Taxes paid for net share settlement of share-based payment awards (in shares)			96
Taxes paid for net share settlement of share-based payment awards	(6,476)		$ (2,177)	(4,299)
Issuance of stock under stock award plans (in shares)		1,024
Issuance of stock under stock award plans	6,737	$ 10		6,727
Stock-based compensation expense	6,402			6,402
Ending balance (in shares) at Jun. 30, 2022		41,677	6,427
Ending balance at Jun. 30, 2022	486,922	$ 417	$ (58,165)	380,083	188,852	(24,265)
Beginning balance (in shares) at Mar. 31, 2022		41,525	6,447
Beginning balance at Mar. 31, 2022	480,504	$ 415	$ (58,310)	376,579	184,726	(22,906)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,126				4,126
Other comprehensive (loss) income	(1,359)					(1,359)
Employee stock purchase plan issuances (in shares)			(23)
Employee stock purchase plan issuances	430		$ 213	217
Taxes paid for net share settlement of share-based payment awards (in shares)			3
Taxes paid for net share settlement of share-based payment awards	(68)		$ (68)	0
Issuance of stock under stock award plans (in shares)		152
Issuance of stock under stock award plans	1,146	$ 2		1,144
Stock-based compensation expense	2,143			2,143
Ending balance (in shares) at Jun. 30, 2022		41,677	6,427
Ending balance at Jun. 30, 2022	$ 486,922	$ 417	$ (58,165)	$ 380,083	$ 188,852	$ (24,265)