Stockholders' Equity (Key Assumptions Used in Determining Fair Value of Options Granted) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stockholders' Equity
Average overall forfeiture rate	6.00%	5.00%	5.00%
Average volatility	42.10%	43.10%	42.50%
Risk-free interest rate	1.20%	0.80%	2.40%
Weighted-average expected life in years	6 years 1 month 6 days	5 years 8 months 12 days	5 years 8 months 12 days