Annual report pursuant to Section 13 and 15(d)

Stock Plans and Management Compensation (Details 3)

v3.20.4
Stock Plans and Management Compensation (Details 3) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
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 $ 1.1 $ 2.8 $ 3.1
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]      
Share-Based Compensation Expense $ 13.8 6.4 5.6
Share-Based Compensation Expense, Tax Benefit 3.4 1.6 1.4
Fair Value of Shares Vested During the Period $ 3.4 $ 4.9 $ 7.8
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding at January 1 88,000    
Awarded Grants in Period 116,000    
Forfeited (37,000)    
Vested 45,000    
Outstanding at December 31 212,000 88,000  
Weighted Average Grant Date Fair Value $ 55.71 $ 53.55  
Awarded - Weighted Average Grant Date Fair Value 63.13    
Forfeited - Weighted Average Grant Date Fair Value 57.71    
Vested - Weighted Average Grant Date Fair Value $ 42.34    
Unrecognized Compensation Cost $ 4.0    
Unrecognized Compensation Cost, Period for Recognition 1 year 6 months    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term 2 years 10 months 24 days 2 years 10 months 24 days 2 years 10 months 24 days
Non-Vested Stock Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-Based Compensation Expense $ 13.3 $ 10.9 $ 11.1
Share-Based Compensation Expense, Tax Benefit 3.3 2.7 2.8
Fair Value of Shares Vested During the Period $ 6.6 $ 19.2 $ 4.4
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding at January 1 444,000    
Awarded Grants in Period 272,000    
Forfeited (58,000)    
Vested 87,000    
Outstanding at December 31 571,000 444,000  
Weighted Average Grant Date Fair Value $ 57.31 $ 53.42  
Awarded - Weighted Average Grant Date Fair Value 64.13 $ 49.12 $ 59.05
Forfeited - Weighted Average Grant Date Fair Value 57.72    
Vested - Weighted Average Grant Date Fair Value $ 58.58    
Unrecognized Compensation Cost $ 11.0    
Age of Grantee   62 years  
Unrecognized Compensation Cost, Period for Recognition 1 year 4 months 24 days    
Awards Vesting Period (in years) 3 years    
Stock Options and SAR's [Member]      
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Age of Grantee   62 years  
Period for Stock Options and SARs to be Exercisable (in years) 10 years    
Awards Vesting Period (in years) 4 years    
Outstanding on December 31 1 year 1 month 6 days    
Exercisable and Vested on December 31 1 year 1 month 6 days    
Vested and Expected to Vest on December 31 1 year 1 month 6 days    
Stock Options and SAR's [Member] | $23.79 [Member]      
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 1 year 1 month 6 days    
Stock Options and SAR's [Member] | Greater Than $14.68 [Member]      
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 1 month 6 days    
Stock Options and SAR's [Member] | $5.87 to $14.68 [Member]      
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 8 months 12 days    
Stock Options and SAR's [Member] | $5.86 [Member]      
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding Options, Weighted Average Remaining Years of Contractual Life (in years) 0 years    
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) $ 61.91 $ 47.61 $ 57.19
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Awarded Grants in Period 26,750 24,605 24,490
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) $ 64.72 $ 49.64 $ 61.59
Risk-Free Interest Rate 1.40% 2.90% 2.40%
Dividend Yield 1.50% 1.70% 1.30%
Volatility Factor 46.60% 41.00% 38.90%