Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Income Taxes
Effective tax rate on income before provision for income taxes including income attributable to noncontrolling interests (as a percent)	29.00%	28.60%
Effective tax rate on income before provision for income taxes and noncontrolling interests (as a percent)	29.00%	29.00%
Federal statutory income tax rate (as a percent)	21.00%	21.00%
Minimum period of statute of limitations of state and foreign jurisdictions	3 years
Maximum period of statute of limitations of state and foreign jurisdictions	5 years
Deferred FICA tax payments reserve	$ 27.6