Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2015	Nov. 30, 2014
Numerator:
Net income for basic and diluted earnings per common share	$ 23,547	$ 19,965	$ 60,714	$ 48,659
Denominator:
Denominator for basic earnings per common share-weighted average shares (shares)	25,823	25,700	25,787	25,660
Effect of dilutive securities:
Employee and Director stock awards (shares)	154	94	133	104
Denominator for diluted earnings per common share (shares)	25,977	25,794	25,920	25,764
Earnings per share basic and diluted:
Basic earnings per Common share (usd per share)	$ 0.91	$ 0.78	$ 2.35	$ 1.90
Diluted earnings per common share (usd per share)	$ 0.91	$ 0.77	$ 2.34	$ 1.89