Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Successor
Current assets
Allowance for doubtful accounts	$ 4.6
Stockholders' equity
Treasury stock, shares (in shares)	2.5
Successor | Convertible Preferred Stock
Stockholders' equity
Preferred stock, par value per share (in dollars per share)	$ 0.01
Preferred stock, shares authorized (in shares)	50.0
Preferred stock, shares issued (in shares)	30.0
Preferred stock, shares outstanding (in shares)	15.9
Successor | Preferred Stock
Stockholders' equity
Preferred stock, par value per share (in dollars per share)	$ 0.01
Preferred stock, shares authorized (in shares)	50.0
Preferred stock, shares issued (in shares)	0.0
Preferred stock, shares outstanding (in shares)	0.0
Successor | Series Common Stock
Stockholders' equity
Common stock, par value per share (in dollars per share)	$ 0.01
Common stock, shares authorized (in shares)	50.0
Common stock, shares issued (in shares)	0.0
Common stock, shares outstanding (in shares)	0.0
Successor | Common Stock
Stockholders' equity
Common stock, par value per share (in dollars per share)	$ 0.01
Common stock, shares authorized (in shares)	450.0
Common stock, shares issued (in shares)	106.0
Common stock, shares outstanding (in shares)	102.7
Predecessor
Current assets
Allowance for doubtful accounts		$ 13.1
Stockholders' equity
Treasury stock, shares (in shares)		0.8
Predecessor | Preferred Stock
Stockholders' equity
Preferred stock, par value per share (in dollars per share)		$ 0.01
Preferred stock, shares authorized (in shares)		10.0
Preferred stock, shares issued (in shares)		0.0
Preferred stock, shares outstanding (in shares)		0.0
Predecessor | Perpetual Preferred Stock
Stockholders' equity
Preferred stock, shares authorized (in shares)		0.8
Preferred stock, shares issued (in shares)		0.0
Preferred stock, shares outstanding (in shares)		0.0
Predecessor | Series Common Stock
Stockholders' equity
Common stock, par value per share (in dollars per share)		$ 0.01
Common stock, shares authorized (in shares)		40.0
Common stock, shares issued (in shares)		0.0
Common stock, shares outstanding (in shares)		0.0
Predecessor | Common Stock
Stockholders' equity
Common stock, par value per share (in dollars per share)		$ 0.01
Common stock, shares authorized (in shares)		53.3
Common stock, shares issued (in shares)		19.3
Common stock, shares outstanding (in shares)		18.5