Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation (Schedule of Weighted Average Assumptions for Restricted Stock Units) (Details)

v3.20.4
Stock-Based Compensation (Schedule of Weighted Average Assumptions for Restricted Stock Units) (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period 3 years 9 months 14 days 3 years 9 months 3 days 3 years 9 months 7 days
Expected dividend yield 1.18% 0.97% 1.15%
Estimated average fair value per restricted stock unit granted $ 78.90 $ 94.58 $ 73.74