Income Taxes (Effective Income Tax Rate Reconciliation) (Details)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	21.00%
State taxes, net of federal tax benefit	3.10%	2.60%
Foreign tax expense and tax rate differential	(0.10%)	(0.10%)
Tax benefit from stock option exercises	(2.20%)	(1.10%)
Other, net	(0.30%)	(0.30%)
Effective income tax rate	21.50%	22.10%