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 (Loss) Income
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	4,034				4,034
Other comprehensive (loss) income	(160)					(160)
Employee stock purchase plan issuances (in shares)			(37)
Employee stock purchase plan issuances	671		$ 334	337
Taxes paid for net share settlement of share-based payment awards (in shares)			93
Taxes paid for net share settlement of share-based payment awards	(6,408)		$ (2,109)	4,299
Issuance of stock under stock award plans (in shares)		872
Issuance of stock under stock award plans	5,591	$ 8		5,583
Stock-based compensation expense	4,259			4,259
Ending balance (in shares) at Mar. 31, 2022		41,525	6,447
Ending balance at Mar. 31, 2022	480,504	$ 415	$ (58,310)	376,579	184,726	(22,906)
Beginning balance (in shares) at Dec. 31, 2021		41,413	6,447
Beginning balance at Dec. 31, 2021	474,032	$ 414	$ (58,100)	372,797	181,879	(22,958)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,847				2,847
Other comprehensive (loss) income	52					52
Employee stock purchase plan issuances (in shares)			(19)
Employee stock purchase plan issuances	350		$ 173	177
Taxes paid for net share settlement of share-based payment awards (in shares)			19
Taxes paid for net share settlement of share-based payment awards	(383)		$ (383)
Issuance of stock under stock award plans (in shares)		112
Issuance of stock under stock award plans	1,364	$ 1		1,363
Stock-based compensation expense	2,242			2,242
Ending balance (in shares) at Mar. 31, 2022		41,525	6,447
Ending balance at Mar. 31, 2022	480,504	$ 415	$ (58,310)	376,579	184,726	(22,906)
Beginning balance (in shares) at Sep. 30, 2022		41,950	6,413
Beginning balance at Sep. 30, 2022	501,513	$ 420	$ (58,172)	385,244	200,075	(26,054)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,678				11,678
Other comprehensive (loss) income	1,467					1,467
Employee stock purchase plan issuances (in shares)			(40)
Employee stock purchase plan issuances	1,170		$ 380	790
Taxes paid for net share settlement of share-based payment awards (in shares)			91
Taxes paid for net share settlement of share-based payment awards	(3,654)		$ (3,654)	0
Issuance of stock under stock award plans (in shares)		375
Issuance of stock under stock award plans	1,672	$ 3		1,669
Stock-based compensation expense	6,333			6,333
Ending balance (in shares) at Mar. 31, 2023		42,325	6,464
Ending balance at Mar. 31, 2023	520,179	$ 423	$ (61,446)	394,036	211,753	(24,587)
Beginning balance (in shares) at Dec. 31, 2022		42,199	6,465
Beginning balance at Dec. 31, 2022	509,928	$ 422	$ (60,973)	389,390	205,854	(24,765)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,899				5,899
Other comprehensive (loss) income	178					178
Employee stock purchase plan issuances (in shares)			(20)
Employee stock purchase plan issuances	576		$ 194	382
Taxes paid for net share settlement of share-based payment awards (in shares)			19
Taxes paid for net share settlement of share-based payment awards	(667)		$ (667)
Issuance of stock under stock award plans (in shares)		126
Issuance of stock under stock award plans	800	$ 1		799
Stock-based compensation expense	3,465			3,465
Ending balance (in shares) at Mar. 31, 2023		42,325	6,464
Ending balance at Mar. 31, 2023	$ 520,179	$ 423	$ (61,446)	$ 394,036	$ 211,753	$ (24,587)