EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 24,395	$ 21,074	$ 19,372	$ 17,841	$ 16,010	$ 14,610	$ 13,154	$ 12,182	$ 82,682	$ 55,956	$ 40,291
Preferred stock dividends									(309)	(309)	(835)
Net income attributable to common shareholders	$ 24,318	$ 20,997	$ 19,294	$ 17,764	$ 15,933	$ 14,533	$ 13,077	$ 12,104	$ 82,373	$ 55,647	$ 39,456
Average common shares issued and outstanding									14,984,961	14,039,809	12,758,381
Average unvested restricted stock grant and RSU shares									309,516	328,015	398,265
Total qualifying shares									15,294,477	14,367,824	13,156,646
Earnings per common share (dollars per share)	$ 1.55	$ 1.35	$ 1.27	$ 1.20	$ 1.09	$ 1.00	$ 0.92	$ 0.85	$ 5.39	$ 3.87	$ 3.00
Preferred stock dividends to dilutive convertible preferred									$ 0	$ 0	$ 533
Dilutive net income attributable to common shareholders									$ 82,373	$ 55,647	$ 39,989
Average common shares issued and outstanding									15,294,477	14,367,824	13,156,646
Dilutive effect of stock options									56,614	74,868	88,519
Dilutive effect of convertible preferred stock									0	0	574,247
Total dilutive common shares issued and outstanding									15,351,091	14,442,692	13,819,412
Diluted earnings per share (dollars per share)	$ 1.54	$ 1.35	$ 1.26	$ 1.20	$ 1.09	$ 1.00	$ 0.91	$ 0.85	$ 5.37	$ 3.85	$ 2.89