Earnings Per Share - Summary of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2016	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2015
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1,319
Document Fiscal Year Focus					2016
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share	$ (1.04)		$ 0.44		$ (1.34)	$ 0.55
Net Income (Loss) Available to Common Stockholders, Basic	$ (132.9)		$ (75.6)
Weighted Average Number of Shares Outstanding, Diluted	201,626		196,878		201,443	197,920
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent						$ 125.7
Net income (loss) attributable to common and participating preferred stockholders	$ (132.9)		$ (75.6)		$ (191.5)	(413.7)
Net Income (Loss) Attributable to Parent	(132.9)	$ (24.7)	(75.6)	$ (58.6)	(191.5)	(413.7)
Income (Loss) from Continuing Operations Attributable to Parent	$ 77.4		$ (161.9)		$ 78.7	$ (522.3)
Dilutive adjustments to income (loss) attributable to common shares from assumed conversion of preferred shares, net of tax:
Weighted-average common shares outstanding - basic	198,589		196,878		198,256	197,920
Net loss per common share attributable to controlling interest:
Basic (in dollars per share)	$ (0.67)	$ (0.12)	$ (0.38)	$ (0.30)	$ (0.97)	$ (2.09)
Income (Loss) from Continuing Operations, Per Diluted Share	0.38	(0.01)	(0.82)	0.04	0.39	(2.64)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	(1.06)		0.44		(1.37)	0.55
Earnings Per Share, Diluted	(0.66)	(0.12)	(0.38)	(0.30)	(0.95)	(2.09)
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.39	$ (0.01)	$ (0.82)	$ 0.04	$ 0.40	$ (2.64)
Stock option awards [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements					1,223
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		1,282		0	1,358
Restricted stock awards [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Incremental Common Shares Attributable To Conversion Of Restricted Stock Units	1,718				1,964
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		3,014		0	2,701
HGI [Member] | Warrant [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price					$ 13.13		$ 13.13