XML 72 R60.htm IDEA: XBRL DOCUMENT v3.21.2
Stock-Based Compensation Expense - Option Granted Fair Value Calculation Assumptions (Details) - Stock Options
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate, minimum 0.50% 0.30%
Risk-free interest rate, maximum 0.70% 1.70%
Expected option term / Performance Period 4 years  
Expected price volatility, minimum   38.70%
Expected price volatility, maximum   45.10%
Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected option term / Performance Period   4 years
Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Expected option term / Performance Period   5 years