EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2013		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Weighted average number diluted shares outstanding adjustment [Abstract]
Restricted stock awards that contain non-forfeitable rights to dividends (in shares)																	0
Unexercised stock options (in shares)	0								0								0	0
Basic and diluted common shares outstanding [Abstract]
Weighted average common shares outstanding - basic (in shares)																	7,256,000	7,318,000	7,927,000
Effect of dilutive shares (in shares)																	88,000	75,000	72,000
Weighted average shares common outstanding-diluted (in shares)																	7,344,000	7,393,000	7,999,000
Calculation of earnings per common share - basic [Abstract]
Net earnings	$ 9,957		$ 10,297		$ 15,679		$ 8,814		$ 8,910		$ 15,501		$ 11,952		$ 9,477		$ 44,747	$ 45,840	$ 35,273
Net earnings attributable to participating securities																	0	59	307
Net earnings attributable to common share holders																	$ 44,747	$ 45,781	$ 34,966
Earnings per common share - basic (in dollars per share)	$ 1.37	[1]	$ 1.41	[1]	$ 2.16	[1]	$ 1.22	[1]	$ 1.23	[1]	$ 2.14	[1]	$ 1.63	[1]	$ 1.26	[1]	$ 6.17	$ 6.26	$ 4.41
Calculation of earnings per common share - diluted [Abstract]
Net earnings attributable to common shareholders- basic																	$ 44,747	$ 45,781	$ 34,966
Add: undistributed earnings attributable to participating securities																	0	1	3
Net earnings attributable to common shareholders- diluted																	$ 44,747	$ 45,782	$ 34,969
Earnings per share - diluted (in dollars per share)	$ 1.36	[1]	$ 1.40	[1]	$ 2.15	[1]	$ 1.21	[1]	$ 1.22	[1]	$ 2.13	[1]	$ 1.63	[1]	$ 1.25	[1]	$ 6.09	$ 6.19	$ 4.37

[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.