Inventory (Narrative) (Details) - USD ($)	12 Months Ended			24 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Inventory [Line Items]
Percentage of LIFO Inventory	89.00%	90.00%		90.00%
Excess of Replacement or Current Costs over Stated LIFO Value	$ 227,200,000	$ 186,500,000		$ 186,500,000
Inventory, LIFO Reserve, Effect on Income, Net	4,100,000			0
Inventory Valuation Reserves	8,600,000	9,200,000		$ 9,200,000
Inventory Valuation Reserve
Inventory [Line Items]
Reserves for Obsolete Inventories, Period Increase (Decrease)	$ (600,000)	$ 1,400,000	$ (1,400,000)