Earnings Per Share - Summary of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted Average Number of Shares Outstanding, Diluted	201,632	196,997
Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants	1,303
Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends	2,822
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	$ (35.6)	$ 17.0
Net income (loss) attributable to common and participating preferred stockholders	(33.9)	(109.8)
Income (Loss) from Continuing Operations Attributable to Parent	$ 11.1	$ (123.5)
Dilutive adjustments to income (loss) attributable to common shares from assumed conversion of preferred shares, net of tax:
Weighted-average common shares outstanding - basic	197,507	196,997
Net loss per common share attributable to controlling interest:
Basic (in dollars per share)	$ (0.17)	$ (0.56)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	(0.23)	0.07
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.06	$ (0.63)