EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income, as reported	$ 117,890	$ 163,007	$ 123,935
Basic earnings per share
Weighted average shares of common stock outstanding-basic (in shares)	96,227,000	94,798,000	89,242,000
Basic earnings per common share (in dollars per share)	$ 1.23	$ 1.72	$ 1.39
Diluted earnings per share
Weighted average shares of common stock outstanding-basic (in shares)	96,227,000	94,798,000	89,242,000
Incremental shares (in shares)	333,000	305,000	354,000
Diluted (in shares)	96,560,000	95,103,000	89,596,000
Diluted earnings per common share (in dollars per share)	$ 1.22	$ 1.71	$ 1.38
Anti-dilutive securities excluded from the calculation of diluted earnings per share (in shares)	0	74,000	0