Annual report pursuant to Section 13 and 15(d)

Stock Plans and Management Compensation (Details 3)

v3.3.1.900
Stock Plans and Management Compensation (Details 3) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]      
Excess Tax Benefit from Share-based Compensation, Financing Activities $ 7.0 $ 8.4 $ 37.2
Percentage of premium paid out in deferred company common stock 20.00%    
Non-Vested Stock Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense $ 13.6 $ 10.5 $ 10.1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]      
Outstanding at January 1 880,000 815,000 798,000
Granted 258,000 322,000 298,000
Released (293,000) (220,000) (266,000)
Forfeited (11,000) (37,000) (15,000)
Outstanding at December 31 834,000 880,000 815,000
Unrecognized compensation cost $ 5.3    
Unrecognized compensation cost, period for recognition 1 year 1 month 16 days    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 53.77 $ 40.41 $ 34.64
Performance Shares [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense $ 8.0 $ 6.5 $ 5.0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]      
Outstanding at January 1 376,000 249,000 96,000
Granted 167,000 152,000 153,000
Released (116,000) 0 0
Forfeited (3,000) (25,000) 0
Outstanding at December 31 424,000 376,000 249,000
Unrecognized compensation cost $ 1.6    
Unrecognized compensation cost, period for recognition 1 year 7 months 6 days    
Certain officers and certain senior managers [Member] | Performance Shares [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average price at grant date (in dollars per share) $ 52.39 $ 40.44 $ 34.65
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]      
Granted 22,990 24,600 26,000
Certain senior executives [Member] | Performance Shares [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average price at grant date (in dollars per share) $ 56.17 $ 41.38 $ 35.93
Risk-free interest rate 1.00% 0.60% 0.40%
Dividend yield 0.90% 1.00% 0.10%
Volatility factor 39.20% 43.70% 53.00%
Weighted average expected life (in years) 2 years 10 months 24 days 2 years 10 months 24 days 2 years 10 months 24 days