Consolidated Statements of Income - USD ($)	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Statement [Abstract]
Revenues	$ 503,584,000	$ 492,625,000	$ 478,816,000
Cost of revenues	399,040,000	392,656,000	370,335,000
Gross profit	104,544,000	99,969,000	108,481,000
General and administrative	58,484,000	54,405,000	51,974,000
Income before income taxes	46,060,000	45,564,000	56,507,000
Income tax provision	17,535,000	16,974,000	22,115,000
Net income	$ 28,525,000	$ 28,590,000	$ 34,392,000
Net income per share:
Basic	$ 1.44	$ 1.38	$ 1.63
Diluted	$ 1.43	$ 1.37	$ 1.61
Weighted average shares outstanding:
Basic	19,826,000	20,669,000	21,104,000
Diluted	20,004,000	20,890,000	21,372,000