Information on Business Segments (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) customer	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments	3
Concentration risk, number of customers | customer	5
Sales Revenue, Net | Top five customers
Segment Reporting Information [Line Items]
Concentration risk, sales	$ 615.1	$ 663.5	$ 637.7
Sales Revenue, Net | Staples
Segment Reporting Information [Line Items]
Concentration risk, sales		$ 210.5	$ 204.1
Concentration risk, percentage		14.00%	14.00%
Sales Revenue, Net | Wal-Mart
Segment Reporting Information [Line Items]
Concentration risk, sales		$ 161.7
Concentration risk, percentage		10.00%
Sales Revenue, Net | Office Depot
Segment Reporting Information [Line Items]
Concentration risk, sales			$ 152.5
Concentration risk, percentage			10.00%
Accounts Receivable | Top five customers
Segment Reporting Information [Line Items]
Concentration risk, trade account receivable	$ 148.4	$ 162.2