Annual report pursuant to Section 13 and 15(d)

Stock Plans and Management Compensation (Details 3)

v3.22.0.1
Stock Plans and Management Compensation (Details 3) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
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 $ 1.8 $ 1.1 $ 2.8
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 $ 13.5 13.8 6.4
Share-Based Compensation Expense, Tax Benefit 3.3 3.4 1.6
Fair Value of Shares Vested During the Period $ 18.6 $ 3.4 $ 4.9
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding at January 1 212,000    
Awarded Grants in Period 166,000    
Forfeited (1,000)    
Vested (185,000)    
Outstanding at December 31 192,000 212,000  
Weighted Average Grant Date Fair Value $ 76.15 $ 55.71  
Awarded - Weighted Average Grant Date Fair Value 76.89    
Forfeited - Weighted Average Grant Date Fair Value 87.48    
Vested - Weighted Average Grant Date Fair Value $ 53.35    
Unrecognized Compensation Cost $ 6.4    
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 $ 16.3 $ 13.3 $ 10.9
Share-Based Compensation Expense, Tax Benefit 4.0 3.3 2.7
Fair Value of Shares Vested During the Period $ 11.3 $ 6.6 $ 19.2
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Outstanding at January 1 571,000    
Awarded Grants in Period 190,000    
Forfeited (14,000)    
Vested (112,000)    
Outstanding at December 31 635,000 571,000  
Weighted Average Grant Date Fair Value $ 66.81 $ 57.31  
Awarded - Weighted Average Grant Date Fair Value 91.14 $ 64.13 $ 49.12
Forfeited - Weighted Average Grant Date Fair Value 66.39    
Vested - Weighted Average Grant Date Fair Value $ 59.71    
Unrecognized Compensation Cost $ 12.0    
Age of Grantee   62 years  
Unrecognized Compensation Cost, Period for Recognition 1 year 2 months 12 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 month 6 days    
Exercisable and Vested on December 31 1 month 6 days    
Vested and Expected to Vest on December 31 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) $ 87.48 $ 61.91 $ 47.61
Share-Based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Awarded Grants in Period 24,560 26,750 24,605
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) $ 91.44 $ 64.72 $ 49.64
Risk-Free Interest Rate 0.20% 1.40% 2.90%
Dividend Yield 1.20% 1.50% 1.70%
Volatility Factor 65.60% 46.60% 41.00%