Summary of Significant Accounting Policies, Shipping Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Shipping Costs [Abstract]
Shipping costs	$ 4.4	$ 3.8	$ 13.6	$ 10.5