CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2013
CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
Net sales	$ 1,143,282		$ 1,057,536		$ 983,112
Cost of sales	898,735		840,623		778,339
Gross profit	244,547		216,913		204,773
Professional and other fees	6,508		9,041		13,098
Salaries and benefits	138,086		123,151		110,963
General and administrative expenses	26,864		22,675		20,099
Interest and financing costs	2,379		1,948		1,868
Operating expenses	173,837		156,815		146,028
Operating income	70,710		60,098		58,745
Other income	7,603		0		0
Earnings before tax	78,313		60,098		58,745
Provision for income taxes	32,473		24,825		23,915
Net earnings	$ 45,840		$ 35,273		$ 34,830
Net earnings per common share - basic (in dollars per share)	$ 6.26	[1]	$ 4.41	[1]	$ 4.37
Net earnings per common share - diluted (in dollars per share)	$ 6.19	[1]	$ 4.37	[1]	$ 4.32
Weighted average common shares outstanding - basic (in shares)	7,318		7,927		7,810
Weighted average common shares outstanding - diluted (in shares)	7,393		7,999		7,903

[1] Basic and diluted earnings per share are computed independently for each of the quarters presented. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted earnings per share.