Stock Based Compensation (Restricted Stock Units Activity) (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, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Shares, Outstanding at Beginning of Year	214,981
Shares, Granted	219,749
Shares, Vested	(203,032)
Shares, Canceled	(8,800)
Shares, Outstanding at End of Year	222,898	214,981
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Shares, Outstanding at Beginning of Year, Weighted Average Grant Date Fair Value	$ 50.41
Shares, Granted, Weighted Average Grant Date Fair Value	58.85	$ 56.24	$ 49.34
Shares, Vested, Weighted Average Grant Date Fair Value	55.20
Shares, Canceled, Weighted Average Grant Date Fair Value	54.13
Shares, Outstanding at End of Year, Weighted Average Grant Date Fair Value	$ 54.21	$ 50.41
Shares, Outstanding at End of Year, Weighted Average Remaining Years Contractual Term	10 months 24 days
Shares, Outstanding at End of Year, Aggregate Intrinsic Value	$ 12,994,953