Annual report pursuant to Section 13 and 15(d)

Stock Plans and Management Compensation (Details 3)

v3.19.3.a.u2
Stock Plans and Management Compensation (Details 3) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Excess Tax Benefit from Share-Based Compensation, Financing Activities $ 2.8 $ 3.1 $ 7.4
Percentage of Premium Paid Out in Deferred Company Common Stock 20.00%    
Performance Shares [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected Life of Award 2 years 10 months 24 days 2 years 10 months 24 days 2 years 10 months 24 days
Share-Based Compensation Expense $ 6.4 $ 5.6 $ 6.2
Share-Based Compensation Expense, Tax Benefit 1.6 1.4 2.4
Fair Value of Shares Vested During the Period $ 4.9 $ 7.8 $ 5.5
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding at January 1 91,000    
Awarded Grants in Period 137,000    
Forfeited (59,000)    
Vested (81,000)    
Outstanding at December 31 88,000 91,000  
Weighted Average Grant Date Fair Value $ 53.55 $ 61.32  
Awarded - Weighted Average Grant Date Fair Value 48.92    
Forfeited - Weighted Average Grant Date Fair Value 49.30    
Vested - Weighted Average Grant Date Fair Value $ 57.49    
Unrecognized Compensation Cost $ 2.3    
Unrecognized Compensation Cost, Period for Recognition 1 year 7 months 6 days    
Share-based Payment Arrangement, Tranche Two [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) $ 47.61 $ 57.19 $ 58.77
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Awarded Grants in Period 24,605 24,490 26,300
Share-based Payment Arrangement, Tranche One [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) $ 49.64 $ 61.59 $ 64.82
Risk-Free Interest Rate 2.90% 2.40% 1.50%
Dividend Yield 1.70% 1.30% 1.10%
Volatility Factor 41.00% 38.90% 38.30%