UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Total
Balance at Mar. 31, 2020	$ 144	$ 145,197	$ (68,424)	$ 410,219	$ (991)	$ 486,145
Balance (in shares) at Mar. 31, 2020	13,500
Issuance of restricted stock awards	$ 1	0	0	0	0	1
Issuance of restricted stock awards (in shares)	91
Share-based compensation	$ 0	1,885	0	0	0	1,885
Share-based compensation (in shares)	0
Repurchase of common stock	$ 0	0	$ (2,703)	0	0	(2,703)
Repurchase of common stock (in shares)			(38)
Net earnings	0	0	$ 0	17,360	0	17,360
Foreign currency translation adjustment	0	0	0	0	37	37
Balance at Jun. 30, 2020	$ 145	147,082	(71,127)	427,579	(954)	502,725
Balance (in shares) at Jun. 30, 2020	13,553
Balance at Mar. 31, 2020	$ 144	145,197	(68,424)	410,219	(991)	486,145
Balance (in shares) at Mar. 31, 2020	13,500
Net earnings						37,206
Balance at Sep. 30, 2020	$ 145	148,845	(72,911)	447,425	(434)	523,070
Balance (in shares) at Sep. 30, 2020	13,537
Balance at Jun. 30, 2020	$ 145	147,082	(71,127)	427,579	(954)	502,725
Balance (in shares) at Jun. 30, 2020	13,553
Issuance of restricted stock awards	$ 0	0	0	0	0	0
Issuance of restricted stock awards (in shares)	8
Share-based compensation	$ 0	1,763	0	0	0	1,763
Share-based compensation (in shares)	0
Repurchase of common stock	$ 0	0	$ (1,784)	0	0	(1,784)
Repurchase of common stock (in shares)			(24)
Net earnings	0	0	$ 0	19,846	0	19,846
Foreign currency translation adjustment	0	0	0	0	520	520
Balance at Sep. 30, 2020	$ 145	148,845	(72,911)	447,425	(434)	523,070
Balance (in shares) at Sep. 30, 2020	13,537
Balance at Mar. 31, 2021	$ 145	152,366	(75,372)	484,616	655	$ 562,410
Balance (in shares) at Mar. 31, 2021	13,503					13,503
Issuance of restricted stock awards	$ 1	0	0	0	0	$ 1
Issuance of restricted stock awards (in shares)	78
Share-based compensation	$ 0	1,735	0	0	0	1,735
Share-based compensation (in shares)	0
Repurchase of common stock	$ 0	0	$ (4,111)	0	0	(4,111)
Repurchase of common stock (in shares)			(45)
Net earnings	0	0	$ 0	23,518	0	23,518
Foreign currency translation adjustment	0	0	0	0	66	66
Balance at Jun. 30, 2021	$ 146	154,101	(79,483)	508,134	721	583,619
Balance (in shares) at Jun. 30, 2021	13,536
Balance at Mar. 31, 2021	$ 145	152,366	(75,372)	484,616	655	$ 562,410
Balance (in shares) at Mar. 31, 2021	13,503					13,503
Net earnings						$ 54,931
Balance at Sep. 30, 2021	$ 146	155,941	(82,246)	539,547	215	$ 613,603
Balance (in shares) at Sep. 30, 2021	13,510					13,510
Balance at Jun. 30, 2021	$ 146	154,101	(79,483)	508,134	721	$ 583,619
Balance (in shares) at Jun. 30, 2021	13,536
Issuance of restricted stock awards	$ 0	0	0	0	0	0
Issuance of restricted stock awards (in shares)	6
Share-based compensation	$ 0	1,840	0	0	0	1,840
Share-based compensation (in shares)	0
Repurchase of common stock	$ 0	0	$ (2,763)	0	0	(2,763)
Repurchase of common stock (in shares)			(32)
Net earnings	0	0	$ 0	31,413	0	31,413
Foreign currency translation adjustment	0	0	0	0	(506)	(506)
Balance at Sep. 30, 2021	$ 146	$ 155,941	$ (82,246)	$ 539,547	$ 215	$ 613,603
Balance (in shares) at Sep. 30, 2021	13,510					13,510