XML 104 R90.htm IDEA: XBRL DOCUMENT v3.10.0.1
Capital Stock and Share Based Compensation Plans - Restricted stock and restricted stock unit activity (Details) - Restricted Stock Units (RSUs)
12 Months Ended
Dec. 31, 2018
$ / shares
shares
Dec. 31, 2017
$ / shares
shares
Dec. 31, 2016
$ / shares
shares
Dec. 31, 2015
$ / shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]        
Unvested shares at beginning of period, number of shares | shares 1,187,923 1,425,177 910,041  
Shares and units awarded in period, number of shares | shares 816,771 653,522 996,839  
Shares and units vested in period, number of shares | shares (771,904) (581,920) (444,267)  
Shares and units forfeited in period, number of shares | shares (57,348) (308,856) (37,436)  
Unvested shares at end of period, number of shares | shares 1,175,442 1,187,923 1,425,177  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]        
Unvested shares at beginning of period, weighted-average value (USD per share) $ 15.86 $ 19.99 $ 17.05 $ 18.22
Shares and units awarded in period, weighted-average value (USD per share) 13.28 22.51 15.76  
Shares and units vested in period, weighted-average value (USD per share) 14.16 20.78 17.78  
Shares and units forfeited in period, weighted-average value (USD per share) 16.68 17.20 16.82  
Unvested shares at end of period, weighted-average value (USD per share) $ 15.86 $ 19.99 $ 17.05  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Exercise Price Range [Roll Forward]        
Unvested shares and units, range of exercise prices, beginning of period, lower range (USD per share) 14 12 10  
Unvested shares and units, range of exercise prices, beginning of period, upper range (USD per share) 24 24 24  
Shares and units awarded in period, range of exercise prices, lower range (USD per share) 11 17 13  
Shares and units awarded in period, range of exercise prices, upper range (USD per share) 17 24 18  
Shares and units vested in period, range of exercise prices, lower range (USD per share) 11 14 13  
Shares and units vested in period, range of exercise prices, upper range (USD per share) 18 24 19  
Shares and units forfeited in period, range of exercise prices, lower range (USD per share) 13 14 12  
Shares and units forfeited in period, range of exercise prices, upper range (USD per share) 23 24 24  
Unvested shares and units, range of exercise prices, end of period, lower range (USD per share) 11 14 12  
Unvested shares and units, range of exercise prices, end of period, upper range (USD per share) 24 24 24