Unaudited Condensed Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Series A Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	(Accumulated Deficit) Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning Balance (Predecessor) at Dec. 31, 2016	$ 181.5	$ 0.0	$ 0.2	$ 2,422.0	$ (371.8)	$ (1,399.5)	$ (477.0)	$ 7.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) | Predecessor	(211.7)					(216.5)		4.8
Net realized losses on cash flow hedges (net of $9.1 net tax provision) | Predecessor	18.6						18.6
Postretirement plans and workers’ compensation obligations (net of $2.5 net tax provision) | Predecessor	4.4						4.4
Foreign currency translation adjustment | Predecessor	5.5						5.5
Share-based compensation for equity-classified awards | Predecessor	1.9			1.9
Repurchase of employee common stock relinquished for tax withholding | Predecessor	(0.1)				(0.1)
Distributions to noncontrolling interests | Predecessor	(0.1)							(0.1)
Elimination of Predecessor equity | Predecessor	0.0		(0.2)	(2,423.9)	371.9	1,616.0	448.5	(12.3)
Ending Balance (Predecessor) at Apr. 01, 2017	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Successor equity | Successor	3,131.9	1,305.4	0.7	1,774.9	0.0	0.0	0.0	50.9
Ending Balance (Successor) at Apr. 02, 2017	3,131.9	1,305.4	0.7	1,774.9	0.0	0.0	0.0	50.9
Beginning Balance (Predecessor) at Apr. 01, 2017	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) | Successor	98.7
Foreign currency translation adjustment | Successor	0.5
Ending Balance (Successor) at Jun. 30, 2017	3,231.7	800.7	1.0	2,286.3	0.0	94.9	0.5	48.3
Beginning Balance (Successor) at Apr. 02, 2017	3,131.9	1,305.4	0.7	1,774.9	0.0	0.0	0.0	50.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) | Successor	98.7	0.0	0.0	0.0	0.0	94.9	0.0	3.8
Foreign currency translation adjustment | Successor	0.5						0.5
Warrant conversions | Successor	0.0		0.1	(0.1)
Series A Convertible Preferred Stock conversions | Successor	0.0	(507.7)	0.2	507.5
Series A Convertible Preferred Stock dividends | Successor	0.0	3.0	0.0	(3.0)
Share-based compensation for equity-classified awards | Successor	7.0			7.0
Distributions to noncontrolling interests | Successor	(6.4)							(6.4)
Ending Balance (Successor) at Jun. 30, 2017	$ 3,231.7	$ 800.7	$ 1.0	$ 2,286.3	$ 0.0	$ 94.9	$ 0.5	$ 48.3