Acquisitions (Narrative) (Details) € in Millions, $ in Millions, $ in Millions						1 Months Ended	6 Months Ended	12 Months Ended
	Jul. 02, 2018 USD ($)	Jul. 02, 2018 MXN ($)	Jan. 31, 2017 USD ($)	Jan. 31, 2017 EUR (€)	May 02, 2016 USD ($)	Jan. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Combinations [Abstract]
Goodwill							$ 708.9	$ 708.9	$ 670.3	$ 587.1
Business Acquisition [Line Items]
Cost of acquisitions, net of cash acquired								$ (38.0)	(292.3)	(88.8)
GOBA Acquisition
Business Combinations [Abstract]
Goodwill	$ 2.4
Business Acquisition [Line Items]
Payments to acquire business	39.9	$ 796.8
Business acquisition, consideration held in escrow	5.8	$ 115.0
Escrow period (up to)								5 years
Cash acquired	1.9
Purchase price, net of working capital adjustment	39.9
Cost of acquisitions, net of cash acquired	$ (38.0)
Net sales							$ 19.7
Esselte Acquisition
Business Combinations [Abstract]
Goodwill			$ 106.5
Business Acquisition [Line Items]
Payments to acquire business			326.8	€ 302.9
Cash acquired			34.2
Purchase price, net of working capital adjustment			326.5
Cost of acquisitions, net of cash acquired			$ (292.3)
Net sales						$ 44.2
PA Acquisition
Business Combinations [Abstract]
Goodwill					$ 80.5
Business Acquisition [Line Items]
Payments to acquire business					$ 103.7
Percentage of voting interest acquired					50.00%
Purchase price, net of working capital adjustment					$ 103.7
Consideration transferred					$ 88.8
Percent acquired					100.00%
Revaluation gain/loss on previously held joint-venture equity interest										28.9
Transaction costs										1.3
Australia Stationary Industries | PA Acquisition
Business Acquisition [Line Items]
Percentage of voting interest acquired					50.00%
PA Acquisition | PA Acquisition
Business Acquisition [Line Items]
Minority interest, ownership percentage					19.83%
SG&A Expenses | GOBA Acquisition
Business Acquisition [Line Items]
Transaction costs								$ 1.1
SG&A Expenses | Esselte Acquisition
Business Acquisition [Line Items]
Transaction costs									$ 5.0	$ 9.2