CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Total
Balances at Jan. 31, 2023	$ 2,374	$ 162,208	$ 207,832	$ (88,641)	$ (2,876)	$ 280,897
Balances (in shares) at Jan. 31, 2023	13,441,590
Net income			14,876			14,876
Foreign currency translation gain (loss)					255	255
Net unrealized gains (losses) on available-for-sale securities					(720)	(720)
Stock compensation expense		2,218				2,218
Stock option exercises and restricted stock unit settlements, net		(2,103)		3,050		947
Stock option exercises and restricted stock unit settlements, net (in shares)	81,851
Common stock repurchases				(6,738)		$ (6,738)
Common stock repurchases (in shares)	(169,788)					(169,788)
Cash dividends			(6,699)			$ (6,699)
Balances at Jul. 31, 2023	$ 2,374	162,323	216,009	(92,329)	(3,341)	285,036
Balances (in shares) at Jul. 31, 2023	13,353,653
Balances at Apr. 30, 2023	$ 2,374	161,347	206,584	(89,883)	(2,473)	277,949
Balances (in shares) at Apr. 30, 2023	13,414,404
Net income			12,767			12,767
Foreign currency translation gain (loss)					(185)	(185)
Net unrealized gains (losses) on available-for-sale securities					(683)	(683)
Stock compensation expense		1,184				1,184
Stock option exercises and restricted stock unit settlements, net		(208)		611		403
Stock option exercises and restricted stock unit settlements, net (in shares)	16,381
Common stock repurchases				(3,057)		(3,057)
Common stock repurchases (in shares)	(77,132)
Cash dividends			(3,342)			(3,342)
Balances at Jul. 31, 2023	$ 2,374	162,323	216,009	(92,329)	(3,341)	285,036
Balances (in shares) at Jul. 31, 2023	13,353,653
Balances at Jan. 31, 2024	$ 2,374	164,183	225,507	(97,528)	(3,597)	290,939
Balances (in shares) at Jan. 31, 2024	13,242,520
Net income			26,080			26,080
Foreign currency translation gain (loss)					(976)	(976)
Net unrealized gains (losses) on available-for-sale securities					490	490
Stock compensation expense		2,215				$ 2,215
Stock option exercises and restricted stock unit settlements (in shares)						627,000
Stock option exercises and restricted stock unit settlements, net		(496)		(1,929)		$ (2,425)
Stock option exercises and restricted stock unit settlements, net (in shares)	260,630
Common stock repurchases				(187)		$ (187)
Common stock repurchases (in shares)	(5,600)					(5,600)
Cash dividends			(8,068)			$ (8,068)
Balances at Jul. 31, 2024	$ 2,374	165,902	243,519	(99,644)	(4,083)	308,068
Balances (in shares) at Jul. 31, 2024	13,497,550
Balances at Apr. 30, 2024	$ 2,374	164,501	229,364	(97,728)	(5,356)	293,155
Balances (in shares) at Apr. 30, 2024	13,350,180
Net income			18,198			18,198
Foreign currency translation gain (loss)					(186)	(186)
Net unrealized gains (losses) on available-for-sale securities					1,459	1,459
Stock compensation expense		1,004				1,004
Stock option exercises and restricted stock unit settlements, net		397		(1,916)		(1,519)
Stock option exercises and restricted stock unit settlements, net (in shares)	147,370
Cash dividends			(4,043)			(4,043)
Balances at Jul. 31, 2024	$ 2,374	$ 165,902	$ 243,519	$ (99,644)	$ (4,083)	$ 308,068
Balances (in shares) at Jul. 31, 2024	13,497,550