Annual report pursuant to Section 13 and 15(d)

EQUITY AND EARNINGS PER SHARE - Outstanding Options (Details)

v3.8.0.1
EQUITY AND EARNINGS PER SHARE - Outstanding Options (Details) - USD ($)
$ / shares in Units, $ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 5,010,576 5,126,906
Options exercisable (in shares) 3,858,081  
Weighted Average Strike Price (in dollars per share) $ 2.55 $ 2.79
Stock Option | Various    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 3,666  
Options exercisable (in shares) 333  
Weighted Average Strike Price (in dollars per share) $ 0.00  
Intrinsic value $ 0.0  
Stock Option | 2002 - 2007    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 587,277  
Options exercisable (in shares) 0  
Weighted Average Strike Price (in dollars per share) $ 0.00  
Fair value at date of grant $ 6.4  
Intrinsic value $ 0.0  
Stock Option | Mar-11    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 311,853  
Options exercisable (in shares) 144,511  
Weighted Average Strike Price (in dollars per share) $ 1.00  
Fair value at date of grant $ 7.0  
Intrinsic value $ 1.0  
Stock Option | Sep-11    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 524,212  
Options exercisable (in shares) 271,425  
Weighted Average Strike Price (in dollars per share) $ 1.00  
Fair value at date of grant $ 5.6  
Intrinsic value $ 1.7  
Stock Option | Apr-12    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 348,352  
Options exercisable (in shares) 209,782  
Weighted Average Strike Price (in dollars per share) $ 1.00  
Fair value at date of grant $ 5.6  
Intrinsic value $ 1.3  
Stock Option | May-12    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 396,316  
Options exercisable (in shares) 237,608  
Weighted Average Strike Price (in dollars per share) $ 1.00  
Fair value at date of grant $ 7.6  
Intrinsic value $ 1.5  
Stock Option | Jul-12    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 437,991  
Options exercisable (in shares) 266,076  
Weighted Average Strike Price (in dollars per share) $ 1.00  
Fair value at date of grant $ 8.3  
Intrinsic value $ 1.6  
Stock Option | Jan-13    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 958,331  
Options exercisable (in shares) 680,862  
Weighted Average Strike Price (in dollars per share) $ 2.32  
Fair value at date of grant $ 18.0  
Intrinsic value $ 3.2  
Stock Option | Feb-13    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 383,331  
Options exercisable (in shares) 272,345  
Weighted Average Strike Price (in dollars per share) $ 2.95  
Fair value at date of grant $ 8.4  
Intrinsic value $ 1.1  
Stock Option | Jun-13    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 670,829  
Options exercisable (in shares) 476,604  
Weighted Average Strike Price (in dollars per share) $ 3.23  
Fair value at date of grant $ 3.8  
Intrinsic value $ 1.9  
Stock Option | Nov-13    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 965,847  
Options exercisable (in shares) 686,202  
Weighted Average Strike Price (in dollars per share) $ 3.57  
Fair value at date of grant $ 6.0  
Intrinsic value $ 2.7  
Stock Option | Aug-14    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock options outstanding (in shares) 765,416  
Options exercisable (in shares) 612,333  
Weighted Average Strike Price (in dollars per share) $ 4.01  
Fair value at date of grant $ 1.7  
Intrinsic value $ 2.3  
Stock Option | Prior to 2008    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (173,853)  
Weighted Average Strike Price (in dollars per share) $ 14.09  
Stock Option | Oct-12    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (15,972)  
Weighted Average Strike Price (in dollars per share) $ 1.48  
Stock Option | Sep-13    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (51,306)  
Weighted Average Strike Price (in dollars per share) $ 1.67  
Stock Option | 2014    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (216,186)  
Weighted Average Strike Price (in dollars per share) $ 1.46  
Stock Option | 2015    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (202,446)  
Weighted Average Strike Price (in dollars per share) $ 1.00  
Stock Option | 2016    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (266,657)  
Weighted Average Strike Price (in dollars per share) $ 3.01  
Stock Option | 2002-2007    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of Options, (in shares) (416,425)