Consolidated Statements of Income (USD $)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
Revenues	$ 492,625,000	$ 478,816,000	$ 429,310,000
Cost of revenues	392,656,000	370,335,000	337,650,000
Gross profit	99,969,000	108,481,000	91,660,000
General and administrative	54,405,000	51,974,000	47,765,000
Income before income taxes	45,564,000	56,507,000	43,895,000
Income tax provision	16,974,000	22,115,000	17,165,000
Net income	$ 28,590,000	$ 34,392,000	$ 26,730,000
Net income per share:
Basic	$ 1.38	$ 1.63	$ 1.20
Diluted	$ 1.37	$ 1.61	$ 1.19
Weighted average shares outstanding:
Basic	20,669,000	21,104,000	22,256,000
Diluted	20,890,000	21,372,000	22,458,000