Consolidated Statements of Income - USD ($)	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenues	$ 646,230,000	$ 552,644,000	$ 592,225,000
Cost of revenues	494,116,000	429,020,000	466,304,000
Gross profit	152,114,000	123,624,000	125,921,000
General and administrative	67,602,000	64,449,000	65,210,000
Income before income taxes	84,512,000	59,175,000	60,711,000
Income tax provision	18,102,000	12,819,000	13,334,000
Net income	$ 66,410,000	$ 46,356,000	$ 47,377,000
Net income per share:
Basic	$ 3.74	$ 2.59	$ 2.59
Diluted	$ 3.66	$ 2.55	$ 2.55
Weighted average shares outstanding:
Basic	17,753,000	17,930,000	18,326,000
Diluted	18,127,000	18,166,000	18,602,000