Net Income (Loss) Per Share (Additional Information) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income from continuing operations	$ 12,734	$ (26,483)	$ 19,688	$ 17,141
Net (loss) income from discontinued operations	(16,368)	6,477	(8,427)	11,538
Net income (loss) from continuing operations	$ (3,634)	$ (20,006)	$ 11,261	$ 28,679
Denominator:
Weighted average common shares outstanding — basic (in shares)	285,284	282,576	284,545	283,366
Dilutive effect of convertible instruments (in shares)	27,041	0	24,339	0
Dilutive effect of employee stock compensation plans (in shares)	7,787	0	8,276	4,848
Weighted average common shares outstanding — diluted (in shares)	320,112	282,576	317,160	288,214
Net income (loss) per common share - basic:
Continuing operations (in dollars per share)	$ 0.04	$ (0.09)	$ 0.07	$ 0.06
Discontinued operations (in dollars per share)	(0.05)	0.02	(0.03)	0.04
Total net (loss) income per basic common share (in dollars per share)	(0.01)	(0.07)	0.04	0.10
Net income (loss) per common share - diluted:
Continuing operations (in dollars per share)	0.04	(0.09)	0.06	0.06
Discontinued operations (in dollars per share)	(0.05)	0.02	(0.03)	0.04
Total net (loss) income per diluted common share (in dollars per share)	$ (0.01)	$ (0.07)	$ 0.03	$ 0.10
Anti-dilutive equity instruments excluded from the calculation (in shares)	38	73	19	39
Contingently issuable awards excluded from the calculation (in shares)	0	2,113	0	1,706