EARNINGS (LOSSES) PER COMMON SHARE - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Income (loss) from continuing operations	$ (77,924)	$ 30,729
Income (loss) from discontinued operations	7,493	(124)
Net income (loss)	(70,431)	30,605
Adjustment for basic earnings (loss) per share
Earnings allocated to unvested shareholders	(361)	(991)
Numerator for basic earnings (loss) per share:
From continuing operations	(78,285)	29,738
From discontinued operations	7,493	(124)
Net income (loss) attributable to parent, basic	(70,792)	29,614
Adjustment for diluted earnings (loss) per share:
Effect of reallocating undistributed earnings of unvested shareholders	0	0
Numerator for diluted earnings (loss) per share:
From continuing operations	(78,285)	29,738
From discontinued operations	7,493	(124)
Net income (loss) attributable to parent, diluted	$ (70,792)	$ 29,614
Denominator:
Denominator for basic earnings (loss) per share – weighted-average shares (in shares)	107,617	108,555
Effect of dilutive shares from stock options, restricted stock and performance share units (in shares)	0	169
Denominator for diluted earnings (loss) per share – adjusted weighted-average shares (in shares)	107,617	108,724
Basic income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	$ (0.73)	$ 0.27
Income from discontinued operations (in dollars per share)	0.07	0
Net income (loss) (in dollars per share)	(0.66)	0.27
Diluted income (loss) per common share:
Income (loss) from continuing operations (in dollars per share)	(0.73)	0.27
Income from discontinued operations (in dollars per share)	0.07	0
Net income (loss) (in dollars per share)	$ (0.66)	$ 0.27