Net Income (Loss) Per Share (Additional Information) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income	$ 16,662		$ 9,259	$ 45,341	$ 105,681
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	16,662	$ (20,006)	(687)	51,533	(15,203)
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ 0	$ (20,006)	$ 9,946	$ (6,192)	$ 120,884
Weighted Average Number of Shares Outstanding, Basic	281,281		285,942	282,674	285,064
Dilutive Securities, Effect on Basic Earnings Per Share	6,571		0	5,422	0
Weighted Average Number of Shares Outstanding, Diluted	287,852		285,942	288,096	285,064
Earnings Per Share, Basic	$ 0.06	$ (0.07)	$ 0.03	$ 0.16	$ 0.37
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0		0.03	(0.02)	0.42
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.06	(0.07)	$ 0	$ 0.18	$ (0.05)
Weighted Average Number of Shares, Contingently Issuable	15		2,555	1,841	2,542
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.06	(0.07)	$ 0	$ 0.18	$ (0.05)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	0		0.03	(0.02)	0.42
Earnings Per Share, Diluted	$ 0.06	$ (0.07)	$ 0.03	$ 0.16	$ 0.37
Anti-dilutive common equivalent shares excluded from computation of diluted net income (loss) per share	158		527	93	673