EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Basic and diluted common shares outstanding [Abstract]
Weighted average common shares outstanding-basic (in shares)	7,274,000	7,320,000	7,249,000	7,412,000
Effect of dilutive shares (in shares)	23,000	25,000	61,000	49,000
Weighted average shares common outstanding-diluted (in shares)	7,297,000	7,345,000	7,310,000	7,461,000
Calculation of earnings per common share - basic [Abstract]
Net earnings	$ 15,679	$ 11,952	$ 24,493	$ 21,429
Net earnings attributable to participating securities	0	0	0	55
Net earnings attributable to common shareholders	$ 15,679	$ 11,952	$ 24,493	$ 21,374
Earnings per common share - basic (in dollars per share)	$ 2.16	$ 1.63	$ 3.38	$ 2.88
Calculation of earnings per common share - diluted [Abstract]
Net earnings attributable to common shareholders- basic	$ 15,679	$ 11,952	$ 24,493	$ 21,374
Add: undistributed earnings attributable to participating securities	0	0	0	1
Net earnings attributable to common shareholders- diluted	$ 15,679	$ 11,952	$ 24,493	$ 21,375
Earnings per common share - diluted (in dollars per share)	$ 2.15	$ 1.63	$ 3.35	$ 2.86
Unexercised stock options (in shares)	0	0	0	0