10. Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Effective tax rate	21.90%	22.80%	22.50%	22.80%
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 4.7		$ 4.7
Unrecognized Tax Benefits	$ 54.4		54.4		$ 39.2
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions			$ 13.3