EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Net income	$ 9,886	$ 13,302	$ 43,613	$ 34,705
Less: income attributable to participating securities	(145)	(176)	(392)	(311)
Earnings available to common shares	$ 9,741	$ 13,126	$ 43,221	$ 34,394
Denominator:
Weighted average common shares (Denominator for basic calculation, in shares)	24,332,879	23,752,770	24,004,885	23,768,858
Weighted average effect of dilutive securities:
Share-based compensation (in shares)	480,583	860,722	649,968	935,511
Diluted weighted average common shares (Denominator for diluted calculation, in shares)	24,813,462	24,613,492	24,654,853	24,704,369
Earnings per share:
Basic (in dollars per share)	$ 0.40	$ 0.55	$ 1.80	$ 1.45
Diluted (in dollars per share)	$ 0.39	$ 0.53	$ 1.75	$ 1.39
Outstanding stock options excluded from diluted earnings (in shares)	700,000	500,000	700,000	500,000