Inventory (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Inventory Disclosure [Abstract]
Cost of goods sold, amortization of operating materials	$ 0.4	$ 0.6
Fixed Production Overhead To Cost of Inventory	2.6
Other Cost and Expense, Operating	1.8
Operating Expenses	$ 4.4