Consolidated Income Statements - Unaudited - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
REVENUES	$ 146,970,000	$ 148,176,000	$ 297,109,000	$ 298,574,000
Cost of revenues	114,127,000	116,686,000	231,132,000	235,731,000
Gross profit	32,843,000	31,490,000	65,977,000	62,843,000
General and administrative expenses	16,593,000	15,094,000	32,345,000	31,031,000
Income before income tax provision	16,250,000	16,396,000	33,632,000	31,812,000
Income tax provision	3,379,000	3,607,000	7,354,000	7,245,000
NET INCOME	$ 12,871,000	$ 12,789,000	$ 26,278,000	$ 24,567,000
Net income per common and common equivalent share
Basic	$ 0.70	$ 0.68	$ 1.42	$ 1.30
Diluted	$ 0.69	$ 0.67	$ 1.40	$ 1.29
Weighted average common and common equivalent shares
Basic	18,452,000	18,877,000	18,488,000	18,899,000
Diluted	18,771,000	19,089,000	18,779,000	19,095,000