Supplemental Data - Advertising and Research and Development, Accounts Receivable, Inventory, Prepaid and Other Current Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Advertising and Research Development Expenses
Advertising expense	$ 6.0	$ 6.2	$ 6.8
Research and development expense	8.9	9.4	$ 6.8
Accounts Receivable - net
From customers	117.0	98.0
Less allowance for doubtful accounts and sales discounts	(1.3)	(1.5)
Total	115.7	96.5
Inventories by Major Class:
Raw materials	36.2	31.6
Work in progress	35.0	26.8
Finished goods	79.2	63.0
Supplies and other	3.6	3.1
Inventories, gross	154.0	124.5
Excess of FIFO over LIFO cost	(10.5)	(8.2)
Total	143.5	116.3
FIFO values of inventories valued on the LIFO method	120.1	106.8
Decrease in LIFO inventory	0.5	0.1
Prepaid and Other Current Assets
Prepaid and other current assets	11.3	10.5
Spare parts	6.9	5.8
Receivable for income taxes	3.3	4.1
Total	$ 21.5	$ 20.4