EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Numerator:
Earnings available to common shares	$ 9,420	$ 5,530	$ 19,123	$ 15,945
Denominator:
Weighted average common shares (Denominator for basic calculation, in shares)	22,974,000	22,768,000	22,914,000	22,624,000
Weighted average effect of dilutive securities:
Share-based compensation (in shares)	897,000	1,012,000	841,000	754,000
Diluted weighted average common shares (Denominator for diluted calculation, in shares)	23,871,000	23,780,000	23,755,000	23,378,000
Earnings per share:
Basic (in dollars per share)	$ 0.41	$ 0.24	$ 0.84	$ 0.70
Diluted (in dollars per share)	$ 0.40	$ 0.23	$ 0.81	$ 0.68
Outstanding stock options excluded from diluted earnings (in shares)	1,500,000	400,000	2,000,000	1,300,000