Goodwill and Other Intangible Assets (Schedule of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Jan. 03, 2019	Dec. 31, 2018	Mar. 14, 2018	Feb. 21, 2018
Goodwill [Line Items]
Goodwill				$ 911.3		$ 852.8
Accumulated goodwill impairment loss				(808.3)		(808.3)
Goodwill, net of accumulated goodwill impairment loss	$ 44.5	$ 44.5	$ 0.0	103.0		44.5
Goodwill [Roll Forward]
Goodwill, beginning balance	44.5	0.0
Acquisitions	58.5	54.6	0.0
Goodwill, ending balance	103.0	44.5	0.0
Ivie and Associates
Goodwill [Line Items]
Goodwill, net of accumulated goodwill impairment loss								$ 28.3
Goodwill [Roll Forward]
Acquisitions	28.3
Rise Interactive
Goodwill [Line Items]
Goodwill, net of accumulated goodwill impairment loss							$ 26.3
Goodwill [Roll Forward]
Acquisitions	26.3
Periscope Acquisition
Goodwill [Line Items]
Goodwill, net of accumulated goodwill impairment loss					$ 58.5
Goodwill [Roll Forward]
Acquisitions	58.5
United States Print and Related Services
Goodwill [Line Items]
Goodwill				881.3		822.8
Accumulated goodwill impairment loss				(778.3)		(778.3)
Goodwill, net of accumulated goodwill impairment loss	44.5	0.0	0.0	103.0		44.5
Goodwill [Roll Forward]
Goodwill, beginning balance	44.5	0.0
Goodwill, ending balance	103.0	44.5	0.0
United States Print and Related Services | Ivie and Associates
Goodwill [Roll Forward]
Acquisitions	28.3
United States Print and Related Services | Rise Interactive
Goodwill [Roll Forward]
Acquisitions	26.3
United States Print and Related Services | Periscope Acquisition
Goodwill [Roll Forward]
Acquisitions	58.5
International
Goodwill [Line Items]
Goodwill				30.0		30.0
Accumulated goodwill impairment loss				(30.0)		(30.0)
Goodwill, net of accumulated goodwill impairment loss	0.0	0.0	0.0	$ 0.0		$ 0.0
Goodwill [Roll Forward]
Goodwill, beginning balance	0.0	0.0
Goodwill, ending balance	0.0	0.0	$ 0.0
International | Ivie and Associates
Goodwill [Roll Forward]
Acquisitions	0.0
International | Rise Interactive
Goodwill [Roll Forward]
Acquisitions	0.0
International | Periscope Acquisition
Goodwill [Roll Forward]
Acquisitions	$ 0.0
United States Book Business | Discontinued Operations, Held-for-sale
Goodwill [Roll Forward]
Reclassification of Book business goodwill to discontinued operations (see Note 4)		(10.1)
United States Book Business | Discontinued Operations, Held-for-sale | United States Print and Related Services
Goodwill [Roll Forward]
Reclassification of Book business goodwill to discontinued operations (see Note 4)		(10.1)
United States Book Business | Discontinued Operations, Held-for-sale | International
Goodwill [Roll Forward]
Reclassification of Book business goodwill to discontinued operations (see Note 4)		$ 0.0